A Possibilistic Valid-Time Model

Pons, José Enrique; Billiet, Christophe; Capote, Olga Pons; Tré, Guy De

doi:10.1007/978-3-642-31709-5_43

Cited by 8 publications

(19 citation statements)

References 23 publications

(23 reference statements)

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“…Also, the dates will be given in the format dd/mm/yyyy. Now it is possible to close the current version of an entity by using (38) and (35). This functionality is required to add or update new information about an existing entity in the relation.…”

Section: Definition 8 Valid-time Relation Consider the Following Dementioning

confidence: 99%

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A Relational Model for the Possibilistic Valid-time Approach

Pons¹,

Marín²,

Pons³

et al. 2012

IJCIS

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In real world, it is very common that some objects or concepts have properties with a time-variant or timerelated nature. Modelling this kind of objects or concepts in a (relational) database schema is possible, but time-variant and time-related attributes have an impact on the consistency of the entire database and must be appropriately managed. Therefore, temporal database models have been proposed to deal with this problem in the literature. Time can be affected by imprecision, vagueness and / or uncertainty, since existing time measuring devices are inherently imperfect. Additionally, human beings manage time using temporal indications and temporal notions, which may also be imprecise. However, the imperfection in human-used temporal indications is supported by human interpretation, whereas information systems need appropriate support in order to accomplish this task. Several proposals for dealing with such imperfections when modelling temporal data exist. Some of these proposals transform the temporal data into a compact representation but there is not a formal model for managing and handling uncertainty regarding temporal information. In this work we present a novel model to deal with imprecision in valid-time databases together with the definition and implementation of the data manipulation language, DML.

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Section: Definition 8 Valid-time Relation Consider the Following Dementioning

confidence: 99%

“…Since the time intervals are now possibilistic valid-time periods, PVPs, the auxiliary functions defined in equations (38) to (40) are the basis for the following auxiliary functions. Definition 36.…”

Section: Definition 29 Generalized Fuzzy Temporal Relationmentioning

confidence: 99%

A Relational Model for the Possibilistic Valid-time Approach

Pons¹,

Marín²,

Pons³

et al. 2012

IJCIS

Self Cite

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show abstract

“…These temporal values are usually either time intervals [1] or instants [1], which may informally be seen as infinitesimally short 'periods' or 'points' in time. Based on their interpretation and purpose, temporal values can be classified into several categories, but the presented work will only consider valid-time indications, which indicate when corresponding data is a valid or true representation of the reality modelled by its database [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

“…A lot of database data are produced by humans, but human-made data are prone to imperfections, as some of these data may be vague or imprecise [5], contradictory, incomplete or uncertain [3], [4], [6]. Of course, data representing temporal values may contain such imperfections too [2][3][4], [7].…”

Section: Introductionmentioning

confidence: 99%

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Bipolar Querying of Valid-Time Intervals Subject to Uncertainty

Billiet

Pons

et al. 2013

Flexible Query Answering Systems

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Abstract. Databases model parts of reality by containing data representing properties of real-world objects or concepts. Often, some of these properties are time-related. Thus, databases often contain data representing time-related information. However, as they may be produced by humans, such data or information may contain imperfections like uncertainties. An important purpose of databases is to allow their data to be queried, to allow access to the information these data represent. Users may do this using queries, in which they describe their preferences concerning the data they are (not) interested in. Because users may have both positive and negative such preferences, they may want to query databases in a bipolar way. Such preferences may also have a temporal nature, but, traditionally, temporal query conditions are handled specifically. In this paper, a novel technique is presented to query a valid-time relation containing uncertain valid-time data in a bipolar way, which allows the query to have a single bipolar temporal query condition.

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A Fuzzy Temporal Object-Relational Database: Model and Implementation

Medina

Pons

2014

Int. J. Intell. Syst.

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In real world, some data have a specific temporal validity that must be appropiately managed. To deal with this kind of data, several proposals of temporal databases have been introduced. Moreover, time can also be affected by imprecision, vagueness, and/or uncertainty, since human beings manage time using temporal indications and temporal notions, which may also be imprecise. For this reason, information systems require appropriate support to accomplish this task. In this work, we present a novel possibilistic valid time model for fuzzy databases including the data structures, the integrity constraints, and the DML. Together with this model, we also present its implementation by means of a fuzzy valid time support module on top of a fuzzy object‐relational database system. The integration of these modules allows to perform queries that combines fuzzy valid time constraints together with fuzzy predicates. Besides, the model and implementation proposed support the crisp valid time model as a particular case of the fuzzy valid time support provided.

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A Possibilistic Valid-Time Model

Cited by 8 publications

References 23 publications

A Relational Model for the Possibilistic Valid-time Approach

A Relational Model for the Possibilistic Valid-time Approach

Bipolar Querying of Valid-Time Intervals Subject to Uncertainty

A Fuzzy Temporal Object-Relational Database: Model and Implementation

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