Efficient Management of Short-Lived Data (2005)
Schmidt, Albrecht, Jensen, Christian S.
Motivated by the increasing prominence of loosely-coupled systems, such as mobile and sensor networks, which are characterised by intermittent connectivity and volatile data, we study the tagging of...
Query and Update Efficient B -Tree Based Indexing of (2004)
Christian S. Jensen, Dan Lin, Beng Chin Ooi
A number of emerging applications of data management technology involve the monitoring and querying of large quantities of continuous variables, e.g., the positions of mobile service users, termed...
Indexing the Past, Present and Anticipated (2004)
Mindaugas Pelanis Simonas, Mindaugas Pelanis, Simonas Saltenis, Christian S. Jensen, ...
With the proliferation of wireless communications and geo-positioning, e-services are envisioned that exploit the positions of a set of continuously moving users to provide context-aware...
Curtis E. Dyreson, Michael H. Bohlen, Christian S. Jensen
This paper presents the METAXPath data model and query language. METAXPath extends XPath with support for XML metadata. XPath is a specification language for locations in an XML document. It serves...
Light-Weight Indexing of General Bitemporal (2004)
Saltenis Giedrius Slivinskas, Author(s Rasa Bliujute, Christian S. Jensen, ...
Most data managed by existing, real-world database applications is time referenced. Data warehouses are good examples. Often, two temporal aspects of data are of interest, namely valid time, when...
Research Issues in Clinical Data Warehousing (2004)
Torben Bach Pedersen, Christian S. Jensen
Medical informatics has been an important area for the application of computing and database technology for at least four decades. This area may benefit from the functionality offered by data...
The VLDBJou7wE (2001) / Digital Object Identifier (DOI) 10.1007/s007780100058 (2004)
Simonas Saltenis, Christian S. Jensen
Real-world entities are inherently spatially and temporally referenced, and database applications increasingly exploit databases that record the past, present, and anticipatedfu tu locations of...
Querying the Trajectories of On-Line Mobile (2004)
Christian S. Jensen, Michael H. Bohlen, Heidi Gregersen, Dieter Pfoser, Janne Skyt, ...
Position data is expected to play a central role in a wide range of mobile computing applications, including advertising, leisure, safety, security, tourist, and traffic applications. Applications...
Mapping Temporal ER Diagrams to Relational (2004)
Author(s Heidi Gregersen, Leo Mark, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, ...
Many database applications manage information that varies over time, and most of the database schemas for these applications were designed using one of the several versions of the Entity-Relationship...
Systematic Change Management in (2004)
Rasa Bliujute, Author(s Rasa Bliujute, Simonas Saltenis, Giedrius Slivinskas, Christian S. Jensen, ...
With the widespread and increasing use of data warehousing in industry, the design of effective data warehouses and their maintenance has become a focus of attention. Independently of this, the area...
Replication Gives High Performance Query Processing in Relational (2004)
euristic techniques (e.g. the A # algorithm). Our framework is the first to integrate pointer/data storage and incremental/decremental/recomputation. Our replicated data management problems can be...
Temporal Data Management (2004)
Christian S. Jensen, Richard T. Snodgrass, Senior Member
A wide range of database applications manage time-varying information. Existing database technology currently provides little support for managing such data. The research area of temporal databases...
Spatio-Temporal Data Exchange Standards (2004)
Albrecht Schmidt, Christian S. Jensen
We believe that research that concerns aspects of spatio-temporal data management may benefit from taking into account the various standards for spatio-temporal data formats. For example, this may...
On the Ontological Expressiveness of Temporal (2004)
Heidi Gregersen, Christian S. Jensen
It is widely recognized that temporal aspects of database schemas are prevalent, but also difficult to capture using the ER model. The database research community's response has been to develop...
Three Proposals for a Third-Generation Temporal Data Model (2004)
Christian S. Jensen, Richard Snodgrass
We present three general proposals for a nextgeneration temporal data model. Each of these proposals express a synthesis of a variety of contributions from diverse sources within temporal databases....
Incremental Join of Time-Oriented Data (2004)
Author(s Dieter Pfoser, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, ...
Data warehouses as well as a wide range of other databases exhibit a strong temporal orientation: it is important to track the temporal variation of data over several months or, often, years. In...
Indexing the Positions of Continuously Moving (2004)
Mario A. Lopez, Simonas Saltenis, Scott T, Author(s Simonas Saltenis, Christian S. Jensen, Scott T. Leutenegger, ...
The coming years will witness dramatic advances in wireless communications as well as positioning technologies. As a result, tracking the changing positions of objects capable of continuous movement...
Michael H. Bohlen, Christian S. Jensen, Richard T. Snodgrass
The question of what is a well-designed temporal data model and query language is a di#cult, but also an important one. The consensus temporal query language TSQL2 attempts to take advantage of the...
Adaptable Query Optimization and Evaluation in Temporal Middleware (2004)
Christian S. Jensen, Richard T. Snodgrass, Michael H. Bohlen, Heidi Gregersen, Dieter Pfoser, ...
Time-referenced data are pervasive in most real-world databases. Recent advances in temporal query languages show that such database applications may benefit substantially from built-in temporal...
Nearest Neighbor and Reverse Nearest Neighbor Queries for Moving Objects (2004)
Rimantas Benetis, Christian S. Jensen, Gytis Karciauskas Simonas
With the proliferation of wireless communications and the rapid advances in technologies for tracking the positions of continuously moving objects, algorithms for efficiently answering queries about...
Transaction Timestamping in (Temporal) Databases (2004)
Christian S. Jensen, David B. Lomet
Many database applications need accountability and trace-ability that necessitate retaining previous database states. For a transaction-time database supporting this, the choice of times used to...
Novel Approaches to the Indexing of (2004)
Dieter Pfoser, Christian S. Jensen, Yannis Theodoridis
The domain of spatiotemporal applications is a treasure trove of new types of data and queries. However, work in this area is guided by related research from the spatial and temporal domains, so far,...
Capturing the Uncertainty of Moving-Object (2004)
Dieter Pfoser, Christian S. Jensen
Spatiotemporal applications, such as fleet management and air tra#c control, involving continuously moving objects are increasingly at the focus of research e#orts. The representation of the...
A Conceptual Modeling Language for Spatiotemporal Applications (2004)
Rosanne Price, Nectaria Tryfona, Christian S. Jensen
This paper presents a conceptual modeling language for spatiotemporal applications that offers built-in support for capturing geo-referenced, time-varying information. More specifically, the...
Curtis E. Dyreson Michael H. Bohlen Christian S. Jensen (2004)
Curtis E. Dyreson, Michael H. Bohlen, Christian S. Jensen
This paper presents the METAXPath data model and query language. METAXPath extends XPath with support for XML metadata. XPath is a specification language for locations in an XML document. It serves...
Nectaria Tryfona, Christian S. Jensen
Many exciting potential application areas for database technology manage time-varying, spatial information. In contrast, existing database techniques, languages, and associated tools provide little...
Supporting Imprecision in Multidimensional Databases Using Granularities (2004)
Torben Bach Pedersen, Christian S. Jensen, Curtis E. Dyreson
On-Line Analytical Processing (OLAP) technologies are being used widely, but the lack of effective means of handling data imprecision, which occurs when exact values are not known precisely or are...
R-Tree Based Indexing of General (2004)
Author(s Simonas Saltenis, Christian S. Jensen, Michael H. Bohlen, Curtis E. Dyreson, Heidi Gregersen, ...
Real-world objects are inherently spatially and temporally referenced, and many database applications rely on databases that record the past, present, and anticipated future locations of, e.g.,...
Research Challenges in Location-Enabled M-Services (2004)
Rapid, sustained advances in key computing hardware technologies combine to enable a new class of computing services that aim to meet needs of mobile users. These ubiquitous and intelligent services...
Layered Implementation of Temporal DBMSs---Concepts and Techniques (2004)
Kristian Torp, Christian S. Jensen, Copyright Kristian, Torp Christian, S. Jensen, Michael Bohlen
A wide range of database applications manage time-varying data. Examples include, e.g., accounting, personnel, schedule, and data warehousing applications. At the same time, it is well-known that...
Capturing and Querying Multiple (2004)
Copyright Curtis, E. Dyreson, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, ...
Motivated to a large extentby the substantial and growing prominence of the World-Wide Web and the potential benefits that may be obtained by applying database concepts and techniques to web data...
Ecient Dierential Timeslice Computation (2004)
Kristian Torp, Leo Mark, Christian S. Jensen
Transaction-time databases record all previous database states and are ever-growing, leading to potentially huge quantities of data. For that reason, e#cient query processing and the utilization of...
R-tree Based Indexing of Now-Relative (2004)
Rasa Bliujute, Author(s Rasa Bliujute, Christian S. Jensen, Simonas Saltenis, Giedrius Slivinskas, ...
The databases of a wide range of applications, e.g., in data warehousing, store multiple states of time-evolving data. These databases contain a substantial part of now-relative data: data that...
Tsql2 Language Specification (2004)
Ilsoo Ahn, Gad Ariav, Don Batory, James Cliord, Curtis E. Dyreson, Ramez Elmasri, ...
This document speci#es a temporal extension to the SQL-92 language standard. The language is designated TSQL2
Kristian Torp, Leo Mark, Christian S. Jensen, Senior Member
Transaction-time databases support access to not only the current database state, but also previous database states.
Capturing and Querying Multiple Aspects of Semistructured Data Curtis E. Dyreson (2004)
Curtis E. Dyreson, Michael H. Bohlen, Christian S. Jensen
Motivated to a large extent by the substantial and growing prominence of the World-Wide Web and the potential benefits that may be obtained by applying database concepts and techniques to web data...
A Foundation for Conventional and Temporal Query Optimization Addressing Duplicates (2004)
Christian S. Jensen, Richard T. Snodgrass, Michael H. Bohlen, Heidi Gregersen, ...
Most real-world databases contain substantial amounts of time-referenced, or temporal, data. Recent advances in temporal query languages show that such database applications may benefit substantially...
Transitioning Temporal Support in TSQL2 to (2004)
Richard T. Snodgrass, Copyright Richard, T. Snodgrass, Christian S. Jensen, Andreas Steiner, ...
This document summarizes the proposals before the SQL3 committees to allow the addition of tables with valid-time and transaction-time support into SQL/Temporal, and explains how to use these...
On the Ontological Expressiveness of Temporal (2004)
Christian S. Jensen, Michael H. Bohlen, Heidi Gregersen, Dieter Pfoser, Janne Skyt, ...
It is widely recognized that temporal aspects of database schemas are prevalent, but also difficult to capture using the ER model. The database research community's response has been to develop...
Enhancing an Extensible Query Optimizer with Support for Multiple Equivalence Types (2004)
Giedrius Slivinskas, Christian S. Jensen
Database management systems are continuously being extended with support for new types of data and advanced querying capabilities. In large part because of this, query optimization has remained a...
Object-Relational Management of Multiply Represented Geographic Entities (2004)
Anders Friis-christensen, Christian S. Jensen
Multiple representation occurs when information about the same geographic entity is represented electronically more than once. This occurs frequently in practice, and it invariably results in the...
Stratum Approaches to Temporal DBMS Implementation (2004)
Kristian Torp, Christian S. Jensen, Richard T. Snodgrass
Previous approaches to implementing temporal DBMSs have assumed that a temporal DBMS must be built from scratch, employing an integrated architecture and using new temporal implementation techniques...
Query Plans for Conventional and Temporal Queries Involving Duplicates and Ordering (2004)
Giedrius Slivinskas, Christian S. Jensen, Richard T. Snodgrass
Most real-world database applications contain a substantial portion of time-referenced, or temporal, data. Recent advances in temporal query languages show that such database applications could...
Conceptual Modeling of Time-Varying (2004)
Author(s Heidi Gregersen, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, Curtis E. Dyreson, ...
A wide range of database applications manage information that varies over time. Many of the underlying database schemas of these were designed using one of the several versions, with varying syntax...
Notions of Upward Compatibility of Temporal (2004)
John Bair, Christian S. Jensen, Richard T. Snodgrass, Renato Busatto, ...
Migrating applications from conventional to temporal database management technology has received scant mention in the research literature. This paper formally defines three increasingly restrictive...
Supporting Frequent Updates in R-Trees: A Bottom-Up Approach Mong Li Lee (2004)
Mong Li Lee, Wynne Hsu, Christian S. Jensen, Bin Cui
Advances in hardware-related technologies promise to enable new data management applications that monitor continuous processes. In these applications, enormous amounts of state samples are obtained...
Organisation Internationale, De Normalisation, T. Snodgrass, Michael H. Bohlen, Christian S. Jensen, Andreas Steiner
This change proposal speci#es the addition of tables with valid-time support into SQL#Temporal, and explains how to use these facilities to migrate smoothly from a conventional relational system to a...
Correct and Efficient Timestamping of (2004)
Author(s Kristian Torp, Richard Snodgrass, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, Heidi Gregersen, ...
Previous approaches to timestamping temporal data have implicitly assumed that transactions have no duration. In this paper we identify several situations where a sequence of operations over time...
Temporal Entity-Relationship (2004)
Heidi Gregersen, Christian S. Jensen, Senior Member
The Entity-Relationship (ER) model, using varying notations and with some semantic variations, is enjoying a remarkable, and increasing, popularity in both the research community#the computer science...
Semantics of Time-Varying Attributes and Their Use for (2004)
Christian S. Jensen, Richard T. Snodgrass
This paper concerns the design of temporal relational database schemas.
Extending Existing Dependency Theory (2004)
Christian S. Jensen, Richard T. Snodgrass, Michael D. Soo
Normal forms play a central role in the design of relational databases. Several normal forms for temporal relational databases have been proposed. These definitions are particular to specific...
Towards a Data Consistency Modeling and Testing (2004)
Jan Pettersen Nytun, Christian S. Jensen, Vladimir A. Oleshchuk
The number of online data sources is continuously increasing, and related data are often available from several sources. However accessing data from multiple sources is hindered by the use of...
Mobile E-Services and Their Challenges to Data Warehousing (2004)
Christian S. Jensen, Torben Bach Pedersen
Continued advances in hardware technologies combine to create a new class of information services, termed mobile e-services, or simply m-services, which exploits the advances in, among others,...
Organisation Internationale, De Normalisation, T. Snodgrass, Michael H. Bohlen, Christian S. Jensen, Andreas Steiner
Transaction time identi#es when data was asserted in the database. If transaction time is supported, the states of the database at all previous points of time are retained.
Stratum Approaches to Temporal DBMS (2004)
Author(s Kristian Torp, Christian S. Jensen, Richard T. Snodgrass, Michael H. Bohlen, Renato Busatto, Heidi Gregersen, ...
Previous approaches to temporal databases have assumed that a temporal database management system (temporal DBMS) must be implemented from scratch, as an integrated architecture to yield adequate...
Towards Increasingly Update Efficient Moving-Object Indexing (2004)
Current moving-object indexing concentrates on point-objects capable of continuous movement in one-, two-, and three-dimensional Euclidean spaces, and most approaches are based on well-known,...
The VLDB Journal (2004) 13: 1--21 / Digital Object Identifier (DOI) 10.1007/s00778-003-0091-3 (2004)
Christian S. Jensen, Augustas Kligys, Torben Bach Pedersen, Igor Timko
With the recent and continuing advances in areas such as wireless communications and positioning technologies, mobile, location-based services are becoming possible.
Spatio-Temporal Database Support for (2004)
Michael B Ohlen, All Rights Reserved, Author(s Michael Bohlen, Christian S. Jensen, Bjrn Skjellaug, ...
In areas such as finance, marketing, and property and resource management, many database applications manage spatio-temporal data. These applications typically run on top of a relational DBMS and...
Extending Practical Pre-Aggregation (2004)
Torben Bach Pedersen, Christian S. Jensen, Curtis E. Dyreson
On-Line Analytical Processing (OLAP) based on a dimensional view of data is being used increasingly for the purpose of analyzing very large amounts of data. To improve query performance, modern OLAP...
Management of Multiply Represented Geographic Entities (2004)
David Skogan, Christian S. Jensen, Gerhard Skagestein, Nectaria Tryfona
Multiple representation of geographic information occurs when a real-world entity is represented more than once in the same or different databases. In this paper, we propose a new approach to the...
Themes and Challenges in Temporal Databases (2004)
Introduction Since the early eighties, an active temporal database research community has sought new insight into the management of time-referenced, or temporal, data and has developed concepts,...
Christian S. Jensen, Richard T. Snodgrass, Michael D. Soo
this paper are independent of particular covering functions, it is still useful to consider some examples to illustrate the range of possibilities
Temporal Entity-Relationship Models---a Survey Heidi Gregersen and Christian S. Jensen TR-3 (2004)
Author(s Heidi Gregersen, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, Heidi Gregersen, ...
The Entity-Relationship (ER) Model, using varying notations and with some semantic variations, is enjoying a remarkable, and increasing, popularity in both the research community, the computer...
Developing a DataBlade for a New Index (2004)
Author(s Rasa Bliujute, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, ...
Many current and potential applications of database technology, e.g., geographical, medical, spatial, and multimedia applications, require efficient support for the management of data with new,...
Multidimensional Data Modeling (2004)
Torben Bach Pedersen, Bach Pedersen, Christian S. Jensen, Michael H. Bohlen, ...
Systems for On-Line Analytical Processing (OLAP) considerably ease the process of analyzing business data and have become widely used in industry. OLAP systems primarily employ multidimensional data...
Temporal Data Management (2004)
Christian S. Jensen, Copyright Christian, S. Jensen, Richard T. Snodgrass, Michael H. Bohlen, ...
A wide range of database applications manage time-varying information. Existing database technology currently provides little support for managing such data. The research area of temporal databases...
Multidimensional Data Modeling for Complex Data (2004)
Torben Bach Pedersen, Christian S. Jensen
On-Line Analytical Processing (OLAP) systems considerably ease the process of analyzing business data and have become widely used in industry. Such systems primarily employ multidimensional data...
Indexing of Moving Objects for (2004)
Simonas Saltenis, Christian S. Jensen, Michael H. Bohlen, Heidi Gregersen, Dieter Pfoser, ...
With the continued proliferation of wireless networks, e.g., based on such evolving standards as WAP and Bluetooth, visionaries predict that the Internet will soon extend to billions of wireless...
Valid-Time Selection and Projection in TSQL2 (2004)
Suchen Hsu, Christian S. Jensen, Richard T. Snodgrass
Temporal databases have now been studied for more than a decade. During that period of time, numerous query languages have been proposed for temporal databases. One of the essential components of a...
Incremental Join of Time-Oriented Data (2004)
Dieter Pfoser, Christian S. Jensen
Data warehouses as well as a wide range of other databases exhibit a strong temporal orientation: it is important to track the temporal variation of data over several months or years. In addition,...
Vacuuming Temporal Databases (2004)
Author(s Janne Skyt, Christian S. Jensen, Michael H. Bohlen, Renato Busatto, Curtis E. Dyreson, ...
A wide range of real-world database applications, including financial and medical applications, are faced with accountability and trace-ability requirements. These requirements lead to the...
Nectaria Tryfona, Christian S. Jensen
Conceptual data modeling for complex applications, such as multimedia and spatiotemporal applications, often results in large, complicated and difficult-to-comprehend diagrams. One reason for this is...
Persistent Views - A Mechanism for Managing Aging Data (2004)
Janne Skyt, Christian S. Jensen
Enabled by the continued advances in storage technologies, the amounts of on-line data grow at a rapidly increasing pace. This development is witnessed in, e.g., so-called data webhouses that...