Spatio-temporal databases deal with geometries changing over time. The goal of our work is to provide a DBMS data model and query language capable handling such time-dependent geometries, including those continuously that describe moving objects . Two fundamental abstractions are point region , describing for which only the position, or position extent, respectively, interest. We propose present as attribute types suitable operations, is, an abstract type extension language. This paper...

When integrating data from autonomous sources, exact matches of items that represent the same real-world object often fail due to a lack common keys. Yet in many cases structural information is available and can be used match such data. Typically matching must approximate since representations sources differ. We propose pq -grams approximately hierarchical define -gram distance between ordered labeled trees as an effective efficient approximation fanout weighted tree edit distance. prove...

During the past decades significant efforts have been made to propose data structures for answering connectivity queries on fully dynamic graphs, i.e., graphs with frequent insertions and deletions of edges. However, a comprehensive understanding how these perform in practice is missing, since not all them implemented, let alone evaluated experimentally. We provide reference implementations proposed experimentally evaluate wide range graphs. Our findings show that current solutions are ready...

During the past decades significant efforts have been made to propose data structures for answering connectivity queries on fully dynamic graphs, i.e., graphs with frequent insertions and deletions of edges. However, a comprehensive understanding how these perform in practice is missing, since not all them implemented, let alone evaluated experimentally. We provide reference implementations proposed experimentally evaluate wide range graphs. Our findings show that current solutions are ready...

A wide range of database applications manage time-varying data. Many temporal query languages have been proposed, each one the result many carefully made yet subtly interacting design decisions. In this article we advocate a different approach to articulating set requirements, or desiderata, that directly imply syntactic structure and core semantics extension an (arbitrary) nontemporal language. These desiderata facilitate transitioning from language data model, which has received only scant...

The association of timestamps with various data items such as tuples or attribute values is fundamental to the management time varying information. Using intervals in timestamps, do most models, leaves a model variety choices for giving meaning timestamps. Specifically, some models claim be point based while other interval based. chosen important it has pervasive effect on aspects model, including database design, query language properties, and processing techniques, e.g., availability...

When integrating data from autonomous sources, exact matches of items that represent the same real world object often fail due to a lack common keys. Yet in many cases structural information is available and can be used match such data. As running example we use residential address information. Addresses are hierarchical structures present databases. Often they best, if not only, relationship between sources. Typically matching has approximate since representations sources differ.We propose...

Each tuple in a valid-time relation includes an interval attribute T that represents the tuple's valid time. The overlap join between two relations determines all pairs of tuples with overlapping intervals. Although joins are common, existing partitioning and indexing schemes inefficient if data long-lived or intervals intersect partition boundaries.

In order to process interval timestamped data, the sequenced semantics has been proposed. This paper presents a relational algebra solution that provides native support for three properties of semantics: snapshot reducibility, extended and change preservation. We introduce two temporal primitives, splitter aligner, define rules use these primitives reduce operators their nontemporal counterparts. Our supports through adjustment timestamp propagation. have implemented reduction in kernel...

Although research on temporal database systems has been active for about 20 years, implementations have not appeared until recently. This is one reason why current commercial provide only limited functionality. paper summarizes extant state of the art implementations. Rather than being very specific each system we attempted to an indication functionality together with pointers additional information. It hoped that this leads more efforts pushing implementation in near future.

Many databases contain temporal, or time-referenced, data and use intervals to capture the temporal aspect. While SQL-based database management systems (DBMSs) are capable of supporting interval data, support they offer can be improved considerably. A range proposed models query languages ample evidence this effect. Natural queries that very difficult formulate in SQL easy these languages. The increased focus on analytics over historical where generally more complex exacerbates difficulties...

We establish a correspondence between temporal logic and subset of ATSQL, extension SQL-92. In addition, we provide an effective translation from to ATSQL that enables user write high-level queries which are then evaluated against space-efficient representation the database. A reverse translation, also provided in this paper, characterizes expressive power syntactically defined queries.

SummaryVarious studies have shown that honey may contain pyrrolizidine alkaloids (PAs) and thus can pose a potential health risk for consumers. It seems the level of contamination depends on geographical botanical origin honey. The geographically central location Switzerland within Europe accounts various different climate zones, therefore serve as model to study PA in honeys. We analysed 71 honeys between 2009 2011. Honeys from origins were collected regions north south Alps well alpine...

Article Free Access Share on Spatio-temporal database support for legacy applications Authors: Michael Böhlen Department of Computer Science, Aalborg University, Fredrik Bajers Vej 7E DK-9220 øst, Denmark DenmarkView Profile , Christian S. Jensen Bjørn Skjellaug SINTEF Telecom and Informatics, Oslo University Oslo, Gaustadalléen 23, N-0371 Norway NorwayView Authors Info & Claims SAC '98: Proceedings the 1998 ACM symposium Applied ComputingFebruary Pages...

Approximate queries on string data are important due to the prevalence of such in databases and various conventions errors data. We present VSol estimator, a novel technique for estimating selectivity approximate queries. The estimator is based inverse strings makes performance independent number strings. To get we decompose all database into overlapping substrings length q (q-grams) then associate each q-gram with its string: IDs that contain q-gram. use signatures compress strings,...

In data integration applications, a join matches elements that are common to two sources. Often, however, represented slightly different in each source, so an approximate must be used. For XML data, most strategies based on some ordered tree matching technique. But data-centric the order is irrelevant: should match even if their subelement varies. this paper we give solution for of unordered trees. Our windowed pq-grams. We develop efficient technique systematically generate pq-grams...