By supporting the valid and transaction time dimensions, bitemporal databases represent reality more accurately than conventional databases. In this paper, we examine the issues involved in designing efficient access methods for bitemporal databases, and propose the partial-persistence and the double-tree methodologies. The partial-persistence methodology reduces bitemporal queries to partial p...

The presented data model is a novel approach for integrating temporal concepts into a multimedia database system. Multimedia objects are extended with the traditional time dimensions valid time and transaction time. In addition a new time dimension specifically tailored for multimedia data types is presented with semantics that are completely orthogonal to the already established time dimension...

In this paper we consider a class of integrity constraints which describe admissible lifecycles of database objects, and which can be speciied by transition graphs. We present an algorithmic scheme for monitoring such constraints in temporal databases which eeciently support the concept of valid-time. The keys to eecient monitoring lie in storing lifecycle situations with respect to constraints...

The input data of the corporate data warehouse is provided by the data sources, that are integrated. In the temporal database research area, a bitemporal database is a database supporting valid time and transaction time. Valid time is the time when the fact is true in the modeled reality, while transaction time is the time when the fact is stored in the database. Defining a data warehouse as a ...

DEFINITION A valid-time index is a temporal index that enables fast access to valid-time datasets. In a traditional database, an index is used for selection queries. When accessing valid-time databases such selections also involve the valid-time dimension (the time when a fact becomes valid in reality). The characteristics of the valid-time dimension imply various properties that the temporal i...

A bitemporal database is a database explicitly supporting two temporal coordinates, namely the valid time and the transaction time. In this paper we introduce the concept of logical data partitioning in bitemporal databases, where data are partitioned into blocks according to their own natural (temporal) properties and independently on the particular application. In this framework we consider b...

Abstract DNA methylation is one of the best-known epigenetic modifications in mammals. The alteration of DNA methylation patterns has been found to be related to many diseases, including cancer. It is well-known that during carcinogenesis, a site-specific DNA hypermethylation and a global DNA hypomethylation take place. This overall loss of DNA methylation has been proposed as a valid biomarker...

We introduce the temporal component of the stRDF data model and the stSPARQL query language, which have been recently proposed for the representation and querying of linked geospatial data that changes over time. With this temporal component in place, stSPARQL becomes a very expressive query language for linked geospatial data, going beyond the recent OGC standard GeoSPARQL, which has no suppor...

Real-world changes are generally discovered delayed by computer systems. The typical update patterns for traditional data warehouses on an overnight or even weekly basis enlarge this propagation delay until the information is available to knowledge workers. Typically, traditional data warehouses focus on summarized data (at some level) rather than detail data. For active data warehouse environm...

Much research work has recently focused on the problem of representing historical information in XML. This paper describes a number of temporal XML data models and provides their comparison according to the following properties: time dimension (valid time, transaction time), support of temporal elements and attributes, querying possibilities, association to XML Schema/DTD, and influence on XML ...