Andreas Behrend

Andreas Behrend
Technical University of Cologne · Institute for Communications Engineering

About

68
Publications
10,170
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
364
Citations

Publications

Publications (68)
Conference Paper
Linking multiple entities to a real-world object is a time-consuming and error-prone task. Entity Resolution (ER) includes techniques for vectorizing entities (signature), grouping similar entities into partitions (blocking), and matching entity pairs based on specified similarity thresholds (filtering). This paper introduces scoping as a new and i...
Conference Paper
The growth of unstructured, unclean, and incomplete data poses quite a problem on attempts to integrate information from various disparate repositories. This paper describes Inteplato, a scalable web-based framework for domainindependent schema mappings between numerous heterogeneous databases. Starting with schema XML exports, the local schemas ar...
Chapter
Many knowledge graphs (KG) contain spatial and temporal information. Most KG embedding models follow triple-based representation and often neglect the simultaneous consideration of the spatial and temporal aspects. Encoding such higher dimensional knowledge necessitates the consideration of true algebraic and geometric aspects. Hypercomplex algebra...
Article
Full-text available
The publish or perish culture of scholarly communication results in quality and relevance to be are subordinate to quantity. Scientific events such as conferences play an important role in scholarly communication and knowledge exchange. Researchers in many fields, such as computer science, often need to search for events to publish their research r...
Article
Full-text available
Systematic assessment of scientific events has become increasingly important for research communities. A range of metrics (e.g., citations, h-index) have been developed by different research communities to make such assessments effectual. However, most of the metrics for assessing the quality of less formal publication venues and events have not ye...
Conference Paper
Today, most commercial database systems provide some support for the management of temporal data, but the index support for efficiently accessing such data is rather limited. Existing access paths neglect the fact that time intervals are located on the timeline and have a duration, two important pieces of information for querying temporal data. In...
Chapter
Full-text available
Database schema elements such as tables, views, triggers and functions are typically defined with many interrelations. In order to support database users in understanding a given schema, a rule-based approach for analyzing the respective dependencies is proposed using Datalog expressions. We show that many interesting properties of schema elements...
Article
Full-text available
Software developers adapt to the fast-moving nature of software systems with agile development techniques. However, database developers lack the tools and concepts to keep the pace. Whenever the current database schema is evolved, the already existing data needs to be evolved as well. This is usually realized with manually written SQL scripts, whic...
Chapter
Full-text available
We propose the new cloud-based service OpenResearch for managing and analyzing data about scientific events such as conferences and workshops in a persistent and reliable way. This includes data about scientific articles, participants, acceptance rates, submission numbers, impact values as well as organizational details such as program committees,...
Article
Full-text available
We propose the new cloud-based service OpenResearch for managing and analyzing data about scientific events such as conferences and workshops in a persistent and reliable way. This includes data about scientific articles, participants, acceptance rates, submission numbers, impact values as well as organizational details such as program committees,...
Article
Full-text available
Database schema elements such as tables, views, triggers and functions are typically defined with many interrelationships. In order to support database users in understanding a given schema, a rule-based approach for analyzing the respective dependencies is proposed using Datalog expressions. We show that many interesting properties of schema eleme...
Conference Paper
In the last few years, research on database and information system technologies has been rapidly evolving thanks to the new paradigms of software and hardware adopted by modern scientific and more invasive applications. A huge and heterogeneous amount of data should be efficiently stored, managed, and analyzed exploiting proper technologies for suc...
Conference Paper
Full-text available
Database schema elements such as tables, views, triggers and functions are typically defined with many interrelationships. In order to support database users in understanding a given schema, a rule-based approach for analyzing the respective dependencies is proposed using Datalog expressions. We show that many interesting properties of schema eleme...
Conference Paper
Full-text available
We introduce end-to-end support of co-existing schema versions within one database. While it is state of the art to run multiple versions of a continuously developed application concurrently, it is hard to do the same for databases. In order to keep multiple co-existing schema versions alive -- which are all accessing the same data set -- developer...
Article
Situation awareness refers to the capability of systems to perceive an existing or predicted context that determines the values of variables in a changing environment. Despite the enhanced support for managing temporal data, current database systems still lack mechanisms for handling highly dynamic situations in which data may change frequently. We...
Article
Full-text available
We present InVerDa, a tool for end-to-end support of co-existing schema versions within one database. While it is state of the art to run multiple versions of a continuously developed application concurrently, the same is hard for databases. In order to keep multiple co-existing schema versions alive, that all access the same data set, developers u...
Conference Paper
Full-text available
Software developers adapt to the fast-moving nature of software systems with agile development techniques. However, database developers lack the tools and concepts to keep pace. Data, already existing in a running product, needs to be evolved accordingly, usually by manually written SQL scripts. A promising approach in database research is to use a...
Conference Paper
Full-text available
We investigate the possibility to use update propagation methods for optimizing the evaluation of continuous queries. Update propagation allows for the efficient determination of induced changes to derived relations resulting from an explicitly performed base table update. In order to simplify the computation process, we propose the propagation of...
Article
Full-text available
Database systems are more and more employed to analyze an ever increasing amount of temporal data by applying a continuously evolving knowledge and are expected to do this in a timely fashion. Examples are financial services, computer systems monitoring, air traffic monitoring, and patient care. In each of these cases data are processed in order to...
Conference Paper
Full-text available
Most scientific publications are easily accessible nowadays, but their accessibility alone does not yet provide researchers with all services they really need. Researchers investigating a new topic still spend a lot of time searching for the most relevant publications, persons or groups inside the respective community. Even experienced members of a...
Article
Full-text available
The dynamics of belief and knowledge is one of the major components of any autonomous system that should be able to incorporate new pieces of information. In order to apply the rationality result of belief dynamics theory to various practical problems, it should be generalized in two respects: first it should allow a certain part of belief to be de...
Article
While location-aware services, both in professional and private context, are widely used today, not all the available knowledge is exploited. The predicted path moving objects follow when being guided e.g. by a smartphone, is not used, instead only the current position is taken into account. In this article, we describe how the exploitation of not...
Article
Full-text available
The evaluation of continuous queries over data streams often becomes difficult as soon as static context data must be combined with dynamic stream data. This is especially the case if the context data is organized in form of view hierarchies and thus computed from some base facts. In this scenario, typical algebraic optimization strategies fail in...
Article
Full-text available
Scientific literature has become easily accessible by now but a comprehensive analysis of the contents and interrelationships between research papers is often missing. Therefore, a time consuming bibliographical analysis is usually performed by scientists before they can really start their research. This manual process includes the identification o...
Conference Paper
Full-text available
We are witnessing a tremendous increase in internet connected, geo-positioned mobile devices, e.g., smartphones and personal navigation devices. Therefore, location related services are becoming more and more important. This results in a very high load on both communication networks and server-side infrastructure. To avoid an overload we point out...
Conference Paper
Full-text available
In moving object databases, authors usually assume that number and position of objects to be processed are always known in advance. Detecting an unknown moving object and pursuing its movement, however, is usually left to tracking algorithms resting outside the database. Trackers are complex software systems which process sensor data and applicatio...
Article
Full-text available
Logic programs are now used as a representation of object-oriented source code in academic prototypes for about a decade. This representation allows a clear and concise implementation of analyses of the object-oriented source code. The full potential of this approach is far from being explored. In this paper, we report about an application of the w...
Conference Paper
Full-text available
The paradigm of reactive programming has attained more and more interest in recent time. In this paper, we show why reactive programming is a well-suited paradigm for sensor fusion algorithms. As a new contribution, we show how the efficiency of stream-oriented reactive programs can be enhanced by applying the magic update method that originally st...
Article
Full-text available
In modern patient monitoring systems a tremendous amount of data is gathered, stored, and analysed to support doctors in making important decisions in a timely manner. To this end, different types of data from different sources have to be processed such as sensor readings of patients vitals, meta-data like the age and weight of a patient, and histo...
Article
Full-text available
Databases are able to store, manage, and retrieve large amounts and a broad variety of data. However, the task of understanding and reacting to the data is often left to tools or user applications outside the database. As a consequence, monitoring applications are often relying on problem-specific imperative code for data analysis, scattering the a...
Article
Signals are usually post-processed in order to enhance their accuracy and reliability. For instance, sensor data frommoving objects data are often processed by tracking systems which allows for enhancing the provided kinematic information. In high-level fusion systems, this kinematic information can be combined with additional domain-specific data...
Conference Paper
Full-text available
In modern streaming applications a tremendous amount of data is harvested, processed, and stored. Data stream or Complex Event Processing (CEP) engines are used to identify interesting, abnormal, or even dangerous patterns within these streams. In monitoring scenarios, however, often the temporal phases of the observed objects are interesting for t...
Article
Full-text available
Since navigation systems and tracking devices are becoming ubiquitous in our daily life, the development of efficient methods for processing massive sets of mobile objects are of utmost importance. Although future routes of mobile objects are often known in advance in many applications, this information is not fully utilized in most methods so far....
Conference Paper
Full-text available
The Airspace Monitoring System (AIMS) monitors and analyzes flight data streams with respect to the occurrence of arbitrary, freely definable complex events. In contrast to already existing tools which often focus on a single task like flight delay detection, AIMS represents a general approach to a comprehensive analysis of aircraft movements, serv...
Article
Full-text available
Database applications enable users to handle the ever-increasing amount and complexity of data, knowledge as well as the dissemination of information to ensure timely response to critical events. However, the very process of human problem solving, which requires understanding and tracking the evolution of data, knowledge, and events, is still handl...
Article
Full-text available
In this paper, we describe the requirements and benefits for integrating data stream processing with database management systems. Currently, these technologies focus on very different tasks; streams systems extract instances of patterns from streams of transient data, while database systems store, manage, provide access to, and analyze persistent d...
Conference Paper
Full-text available
In data stream systems, it is necessary to access the historical stream data. For example, in a CEP system historical data is necessary for deriving complex events where the underlying atomic events are distributed over a potentially long period of time. Historical stream data is also important in trend analysis systems where new or changed analysi...
Article
Full-text available
Within the research area of deductive databases three different database tasks have been deeply investigated: query evaluation, update propagation and view updating. Over the last thirty years various inference mechanisms have been proposed for realizing these main functionalities of a rule-based system. However, these inference mechanisms have bee...
Conference Paper
Full-text available
In this paper, we present the "Airspace Monitoring System" (AIMS) for monitoring and analyzing flight data streams with respect to the occurrence of arbitrary complex events. In contrast to already existing tools which often focus on a single task like flight delay detection, we want to provide a more general system that allows for a comprehensive...
Article
Zusammenfassung Trackingsysteme stellen Bewegungsinformationen über Objekte zur Verfügung. Diese Bewegungsinformationen können mit zusätzlichen Daten kombiniert werden, um Higher-Level-Fusionssysteme zu konstruieren, die zur Erkennung von Verhaltens- und Bedrohungsmustern dienen und somit zur Situation Awareness beitragen. Muster, die interessante...
Conference Paper
Full-text available
ETL jobs are used to integrate data from distributed and heterogeneous sources into a data warehouse. A well-known challenge in this context is the development of incremental ETL jobs for efficiently maintaining warehouse data in the presence of source data updates. In this paper, we present a new transformation-based approach to automatically deri...
Conference Paper
Full-text available
Being able to activate triggers at timepoints reached or af- ter time intervals elapsed has been acknowledged by many authors as a valuable functionality of a DBMS. Recently, the interest in time-based triggers has been renewed in the context of data stream monitoring. How- ever, up till now SQL triggers react to data changes only, even though rese...
Conference Paper
Full-text available
In moving object databases, many authors assume that num- ber and position of objects to be processed are always known in advance. Detecting an unknown moving object and pursuing its movement, how- ever, is usually left to tracking algorithms outside the database in which the sensor data needed is actually stored. In this paper we present a solutio...
Conference Paper
Full-text available
This paper is concerned with a transformation-based approach to update propagation in an extended version of Codd's relational algebra which allows for defining derived relations (even recursively). It is shown that the desired optimization effects of update propagation may be lost if no generalized selection pushing strategy is employed to the tra...
Conference Paper
Full-text available
In this paper we present a new rule-based approach for consistency preserving view updating in deductive databases. Based on rule transformations performed during schema design, fixpoint evaluations of these rules at run time compute consistent realizations of view update requests. Alternative realizations are expressed using disjunctive Datalog in...
Conference Paper
Full-text available
In this paper we show the usefulness and feasibility of applying conventional SQL queries for analyzing a wide spectrum of data streams. As application area we have chosen the analysis of stock market data, mainly because this kind of application exhibits sufficiently many of those characteristics for which relational query technology can be consid...
Conference Paper
Full-text available
We propose a new approach for enhancing collaborative in- formation retrieval by means of incorporating positional data for a loca- tion-aware personalized retrieval process. In our framework, the col- laboration between users will be established by building communities based on matching user attributes in a uniform user model. This allows for inco...
Conference Paper
Full-text available
In this paper we present a new fixpoint-based approach to bottom-up state generation for stratifiable disjunctive deductive data- bases. To this end, a new consequence operator based on hyperesolution is introduced which extends Minker's operator for positive disjunctive Datalog rules. In contrast to already existing model generation methods our ap...
Conference Paper
Full-text available
TinTO is an experimental system aiming at demonstrating the usefulness and feasibility of applying conventional SQL queries for analyzing a wide spectrum of data streams. As application area we have chosen the analysis of streams of stock market data, mainly because this kind of application exhibits sufficiently many of those characteristics for wh...
Conference Paper
Full-text available
We reconsider query evaluation in stratifiable deductive databases using Magic Sets. On the basis of the soft stratification approach, a new solution to the problem of optimizing existential queries in a set-oriented database language like Datalog is presented. To this end, the query answering process is optimized in such a way that after the gener...
Conference Paper
Full-text available
Update propagation in deductive databases can be imple- mented by combining rule rewriting and fixpoint computation, analo- gous to the way how query answering is performed via Magic Sets. For eciency reasons, bottom-up propagation rules have to be subject to Magic rewriting, thus possibly loosing stratifiability. We propose to use the soft stratif...
Article
Full-text available
In this paper we propose a new bottom-up query evaluation method for stratified deductive databases based on the Magic Set approach. As the Magic Sets rewriting may lead to unstratifiable rules, we propose to use Kerisit's weak consequence operator to compute the well-founded model of magic rules (guaranteed to be two-valued). We show that its appl...
Article
Full-text available
The notion of a deductive database has emerged during the 1970s in order to describe database systems capable of inferring new knowledge using rules. Within this research area three kinds of rule-based extensions for traditional databases have been intensively studied: active, deductive and normative rules. Nowadays, even SQL databases use these ex...
Conference Paper
Full-text available
In this paper we present a bottom-up algorithm for computing the well-founded model of general normal logic programs by means of range-restricted Datalog ⌝ rules automatically generated from the source program. The drawback of repeated computation of facts from which Van Gelder’s alternating fixpoint procedure is sufiering is avoided by using updat...
Article
Full-text available
In this paper, a dynamic approach to deductive query evaluation is presented which combines the effects of different SIP strategies used for the magic set rewriting technique. Given a query execution plan obtained by a single magic set transformation, this plan is normally not reoptimized, and the actual number of facts generated during query proce...
Article
Full-text available
In this paper we survey the various forms of integrity con-straints provided in SQL. A critical discussion of the implications of SQL's approach to integrity follows, particularly identifying misconcep-tions to be found in some textbooks. The relationship between views and constraints in SQL is investigated and contrasted with the state-of-the-art...
Article
Full-text available
Introduction The magic sets rewriting technique (cf. [Ull89]) seems to be the most promising approach to evaluating queries bottom-up for database systems with a powerful view concept. This is in particular the case for systems which will implement the new SQL3 standard and hence will allow the definition of recursive views. It has been shown that...
Article
Full-text available
Tracking systems provide kinematical information of objects in a scenario. This kinematical information can be combined with additional data to build higher-level-fusion systems that allow the detection of behaviour and threat patterns and thus contribute to situation awareness. The patterns that characterize situations of interest may vary over ti...
Article
Full-text available
Bonn, University, Diss., 2004 (Nicht für den Austausch).

Network

Cited By