InstantDB: Enforcing Timely Degradation of Sensitive Data (2008)
Anciaux, N.L.G., Bouganim, L., Pucheral, P., Apers, P.M.G.
People cannot prevent personal information from being collected by various actors. Several security measures are implemented on servers to minimize the possibility of a privacy violation....
Sound ranking algorithms for XML search (2008)
Hiemstra, D., Klinger, S., Rode, H., Flokstra, J., Apers, P.M.G.
Ranking algorithms for XML should reflect the actual combined content and structure constraints of queries, while at the same time producing equal rankings for queries that are semantically equal....
Probabilistic Processing of Interval-valued Sensor Data (2008)
Evers, S., Fokkinga, M.M., Apers, P.M.G.
When dealing with sensors with different time resolutions, it is desirable to model a sensor reading as pertaining to a time interval rather than a unit of time. We introduce two variants on the...
Data Degradation: Making Private Data Less Sensitive Over Time (2008)
Anciaux, N.L.G., Bouganim, L., Pucheral, P., Apers, P.M.G.
Trail disclosure is the leakage of privacy sensitive data, resulting from negligence, attack or abusive scrutinization or usage of personal digital trails. To prevent trail disclosure, data...
Serdyukov, P., Feng, L., Van Bunningen, A.H., Evers, S., Apers, P.M.G., ...
We propose a unified and complete solution for expert finding in organizations, including not only expertise identification, but also expertise selection functionality. The latter two include the use...
The Life-Cycle Policy model (2008)
Anciaux, N.L.G., Bouganim, L., Pucheral, P., Apers, P.M.G.
Our daily life activity leaves digital trails in an increasing number of databases (commercial web sites, internet service providers, search engines, location tracking systems, etc). Personal digital...
Composable Markov Building Blocks (2007)
Evers, S., Fokkinga, M.M., Apers, P.M.G.
In situations where disjunct parts of the same process are described by their own first-order Markov models and only one model applies at a time (activity in one model coincides with non-activity in...
Ranking Query Results using Context-Aware Preferences (2007)
Van Bunningen, A.H., Fokkinga, M.M., Apers, P.M.G., Feng, L.
To better serve users’ information needs without requiring comprehensive queries from users, a simple yet effective technique is to explore the preferences of users. Since these preferences can...
An Answer Explanation Model for Probabilistic Database Queries (2007)
Van Bunningen, A.H., Feng, L., Fokkinga, M.M., Apers, P.M.G.
Following the availability of huge amounts of uncertain data, coming from diverse ranges of applications such as sensors, machine learning or mining approaches, information extraction and...
Exploring personalized life cycle policies (2007)
Anciaux, N.L.G., Fokkinga, M.M., Apers, P.M.G.
Ambient Intelligence imposes many challenges in protecting people's privacy. Storing privacy-sensitive data permanently will inevitably result in privacy violations. Limited retention techniques...
Modeling Uncertain Context Information via Event Probabilities (2006)
Van Bunningen, A.H., Feng, L., Apers, P.M.G.
To be able to support context-awareness in an Ambient Intelligent (AmI) environment, one needs a way to model context. Previous research shows that a good way to model context is using Description...
Using Description Logics to Model Context Aware Query Preferences (2006)
Van Bunningen, A.H., Feng, L., Apers, P.M.G.
Users’ preferences have traditionally been exploited in query personalization to better serve their information needs. With the emerging ubiquitous computing technologies, users will be situated in...
A context-aware preference model for database querying in an Ambient Intelligent environment (2006)
Van Bunningen, A.H., Feng, L., Apers, P.M.G.
Users' preferences have traditionally been exploited in query personalization to better serve their information needs. With the emerging ubiquitous computing technologies, users will be situated in...
Exploiting Query Structure and Document Structure to Improve Document Retrieval Effectiveness (2006)
Mihajlovic, V., Hiemstra, D., Blok, H.E., Apers, P.M.G.
In this paper we present a systematic analysis of document retrieval using unstructured and structured queries within the score region algebra (SRA) structured retrieval framework. The behavior of...
Balancing smartness and privacy for the Ambient Intelligence (2006)
Anciaux, N.L.G., Feng, L., Apers, P.M.G.
Ambient Intelligence (AmI) will introduce large privacy risks. Stored context histories are vulnerable for unauthorized disclosure, thus unlimited storing of privacy-sensitive context data is not...
An XML-IR-DB-Sandwich: Is it Better with an Algebra in Between? (2004)
Mihajlovic, V., Hiemstra, D., Blok, H.E., Apers, P.M.G.
In this paper we address the problem of immediate translation of XPath+IR queries to relational database expressions and exert the benefits of using an intermediate algebra. Adding an intermediate...
CIRQuL: Complex Information Retrieval Query Language (2003)
Mihajlovic, V., Hiemstra, D., Apers, P.M.G.
In this paper we will present a new framework for the retrieval of XML documents. We will describe the extension for existing query languages (XPath and XQuery) geared toward ranked information...
On Region Algebras, XML Databases, and Information Retrieval (2003)
Mihajlovic, V., Hiemstra, D., Apers, P.M.G.
This paper describes some new ideas on developing a logical algebra for databases that manage textual data and support information retrieval functionality. We describe a first prototype of such a...
Content-based video indexing for the support of digital library search (2002)
Petkovic, M., Zwol Van, R., Blok, H.E., Jonker, W., Apers, P.M.G., Windhouwer, M., ...
Presents a digital library search engine that combines efforts of the AMIS and DMW research projects, each covering significant parts of the problem of finding the required information in an enormous...
Data exchange over web-based applications (2002)
Van Zwol, R., Fokkinga, M.M., Jeronimus, V., Apers, P.M.G.
With large volumes of data being exchanged on the Internet, query languages are needed to bridge the gap between databases and the web. Furthermore, the differentiation in data types used by webbased...
Retrieval performance experiment with the webspace method (2002)
Finding relevant information using search engines that index large portions of the World-Wide Web is often a frustrating task. Due to the diversity of the information available, those search engines...
DXL: Data eXchange Language (2001)
Van Zwol, R., Jeronimus, V., Fokkinga, M.M., Apers, P.M.G.
With large volumes of data being exchanged over the Internet query languages are needed to bridge the gap between databases and the web. DXL provides an extendible framework, designed to exchange...
In this paper, we present an approach to global transaction management in workflow environments. The transaction mechanism is based on the well-known notion of compensation, but extended to deal with...
Blok, H.E., De Vries, A.P., Blanken, H.M., Apers, P.M.G.
Data abstraction and query processing techniques are usually studied in the domain of administrative applications. We present a case-study in the non-standard domain of (multimedia) information...
Flexible and scalable digital library search (2001)
Blok, H.E., Windhouwer, M.A., Van Zwol, R., Petkovic, M., Apers, P.M.G., Kersten, M.L., ...
Blok, H.E., Hiemstra, D., Choenni, R.S., Blanken, H.M., Apers, P.M.G.
Efficient, flexible, and scalable integration of full text information retrieval (IR) in a DBMS is not a trivial case. This holds in particular for query optimization in such a context. To facilitate...
Information Access in Multimedia Databases based on Feature Models (2000)
De Vries, A.P., Windhouwer, M.A., Apers, P.M.G., Kersten, M.L.
With the increasing popularity of the WWW, the main challenge in computer science has become content-based retrieval of multimedia objects. Access to multimedia objects in databases has long been...
Using Webspaces to Model Document Collections on the Web (2000)
Due to the unstructured character of data on the web it is hard to find specific information when surfing over the web. Search engines can only rely their results on IR techniques available, and most...
The webspace method: on the integration of database technology with multimedia retrieval (2000)
Large collections of documents containing various types of multimedia, are made available to theWWW. Unfortunately, due to the un-structuredness of Internet environments it is hard to find specific...
Distributed Global Transaction Support for Workflow Management Applications (1999)
Vonk, J., Boertjes, E.M., Apers, P.M.G.
Workflow management systems require advanced transaction support to cope with their inherently long-running processes. The recent trend to distribute workflow executions requires an even more...
The Mirror MMDBMS architecture (1999)
De Vries, A.P., Blanken, H.M., Apers, P.M.G.
Handling large collections of digitized multimedia data, usually referred to as multimedia digital libraries, is a major challenge for information technology. The Mirror DBMS is a research database...
An Architecture for Nested Transaction Support on Standard Database Systems (1998)
Boertjes, E.M., Vonk, J., Apers, P.M.G.
Many applications dealing with complex processes require database support for nested transactions. Current commercial database systems lack this kind of support, offering flat, non-nested...
Integrating organisational and transactional aspects of cooperative activities (1998)
Faase, F.J., Even, S.J., De By, R.A., Apers, P.M.G.
This paper introduces the specification language CoCaA. The features of COCGA are designed for the specification of both organisational and transactional aspects of cooperative activities, based on...
Specifying global behaviour in database federations (1998)
Vermeer, W.W.M., Apers, P.M.G.
We discuss the impact of locally implemented behaviour on global behaviour specification in a federation of object-oriented databases. In particular, given a specification of an integrated view of a...
A Specification Language for the WIDE Workflow Model (1998)
Chan, D.K.C., Vonk, J., Sánchez, G., Apers, P.M.G.
This paper presents a workflow specification language developed in the WIDE project. The language provides a rich organisation model, an information model including presentation details, and a...
Two-Layer Transaction Management for Workflow Management Applications (1997)
Vonk, J., Boertjes, E.M., Apers, P.M.G.
Workflow management applications require advanced transaction management that is not offered by traditional database systems. For this reason, a number of extended transaction models has been...
Behaviour specification in database interoperation (1997)
Vermeer, W.W.M., Apers, P.M.G.
We discuss the impact of locally implemented behaviour in a federation of object-oriented databases. In particular, given a specification of an integrated view of a number of component databases, we...
On the applicability of schema integration techniques to database interoperation (1996)
Vermeer, W.W.M., Apers, P.M.G.
We discuss the applicability of schema integration techniques developed for tightly-coupled database interoperation to interoperation of databases stemming from different modelling contexts. We...
The role of integrity constraints in database interoperation (1996)
Vermeer, W.W.M., Apers, P.M.G.
We present an approach to database interoperation that exploits the semantic information provided by integrity constraints defined on the component databases. We identify two roles of integrity...
Parallel Evaluation of Multi-join Queries (1996)
Wilschut, A.N., Flokstra, J., Apers, P.M.G.
A number of execution strategies for parallel evaluation of multi-join queries have been proposed in the literature. In this paper we give a comparative performance evaluation of four execution...
Van Keulen, M., Skowronek, J., Apers, P.M.G., Balsters, H., Blanken, H.M., De By, R.A., ...
New application domains in data-processing environments pose new requirements on the methodologies, techniques and tools used to design them. The applications’ semantics should be fully represented...
Optimization of Spatial Joins Using Filters (1995)
Veenhof, H.M., Apers, P.M.G., Houtsma, M.A.W.
When viewing present-day technical applications that rely on the use of database systems, one notices that new techniques must be integrated in database management systems to be able to support these...
Reverse engineering of relational database applications (1995)
Vermeer, W.W.M., Apers, P.M.G.
This paper presents techniques for reverse engineering of relational database applications. The target of such an effort is the definition of a fully equipped object-oriented view of the relational...
Parallel evaluation of multi-join queries (1995)
Wilschut, A.N., Flokstra, J., Apers, P.M.G.
A number of execution strategies for parallel evaluation of multi-join queries have been proposed in the literature; their performance was evaluated by simulation. In this paper we give a comparative...
From Nested-Loop to Join Queries in OODB (1994)
Steenhagen, H.J., Apers, P.M.G., Blanken, H.M., De By, R.A.
Most declarative SQL-like query languages for object-oriented database systems are orthogonal languages allowing for arbitrary nesting of expressions in the select-, from-, and where-clause....
Integrity Control in Relational Database Systems - An Overview (1993)
This paper gives an overview of research regarding integrity control or integrity constraint handling in relational database management systems. The topic of constraint handling is discussed from two...
Dataflow Query Execution in a Parallel, Main-memory Environment (1993)
In this paper, the performance and characteristics of the execution of various join-trees on a parallel DBMS are studied. The results of this study are a step into the direction of the design of a...
Algebraic optimization of recursive queries (1992)
Houtsma, M.A.W., Apers, P.M.G.
Over the past few years, much attention has been paid to deductive databases. They offer a logic-based interface, and allow formulation of complex recursive queries. However, they do not offer...
Dynamic Action Scheduling in a Parallel Database System (1992)
This paper describes a scheduling technique for parallel database systems to obtain high performance, both in terms of response time and throughput. The technique enables both intra- and...
Parallelism in a Main-Memory System: The Performance of PRISMA/DB (1992)
Wilschut, A.N., Flokstra, J., Apers, P.M.G.
his paper evaluates the performance of the parallel, main-memory DBMS, PRISMA/DB. First, an abstract architecture for parallel query execution is presented. A performance model for the execution of...
Apers, P.M.G., Scheuermann, P.
We discuss the different types of schema architectures which could be supported by distributed database systems, making a clear distinction between logical, physical, and federated distribution. We...
Implementing PRISMA/DB in an OOPL (1989)
Wilschut, A.N., Apers, P.M.G., Kersten, M.L.
PRISMA/DB is implemented in a parallel object-oriented language to gain insight in the usage of parallelism. This environment allows us to experiment with parallelism by simply changing the...
Optimization Algorithms for Distributed Queries (1983)
Apers, P.M.G., Hevner, A.R., Yao, S.B.
The efficiency of processing strategies for queries in a distributed database is critical for system performance. Methods are studied to minimize the response time and the total time for distributed...