By the events in the past years, the integration of data protection mechanisms into information systems becomes a central research problem again. In this technical report for our poster, we show how query rewriting can be used to maintain privacy of users in smart (or assistive) environments. We developed a privacy respecting query processing and a vertical fragmentation of queries, processing maximal parts of the query as close to the sources of the data (e.g. sensors) as possible.

The need for personal information management using distributed, user-friendly, and personalized document management systems is obvious. State of the art document management systems such as digital libraries provide support for the whole document lifecycle. To enhance such document management systems to get a personalized, distributed and user-friendly information system we present techniques for a simple import of collections, documents, and data, for generic and concrete data modeling, replication, and, personalization. These techniques were employed for the implementation of a personal conference assistant, which was used for the first time at the VLDB conference 2003 in Berlin, Germany. Our client-server architecture provides an information server with different services and different kinds of clients. These services comprise a distribution and replication service, a collection integration service, a data management unit, and, a query processing service.

The integrated management of standard structured data and time-dependent data is still too complex to be covered by a single system. So, there will be distinct systems such as multimedia DBMS and media servers for e.g., video data, each doing only what it can do best. However, some functions desired by users and applications necessarily involve both systems. A prime candidate for this is the use of hypermedia link anchors in continuous media. The idea behind this approach is to enhance the client software to improve the interplay between structured data in the database (hypermedia structures and metadata) and the video stream. On initiating the playout of the video, the client receives a list of anchors from the MMDBS and organizes them in local structures. It also receives a handle for the video to be played out and uses it to contact the media server. The overall architecture and the role of the different kinds of systems are shown. Query and update processing are distributed over the different kinds of servers.

We introduce an evaluation technique for a declarative object-oriented database (OODB) query language. The query language is rule-based and can be evaluated and optimized using an appropriate object algebra. We introduce a new framework which uses concepts of the object-oriented data model to define adequate accesses to the database. Additionally, problems according to the evaluation of recursive queries are discussed.

The metalevel concepts for an object-oriented database model are presented. Usually, systems that include a metaclass concept are either only implicitly supporting the management of meta information, which restricts the application of this concept, or explicitly giving unrestricted access to manipulate metaclasses, which results in inconsistent states of the system. To make the explicit support more system-controlled, the metascheme is partitioned into two parts: the system view and the application view. Possible scheme level operations, the representation of methods and their implementation as a special kind of meta information, and a simple extension to the query algebra of the underlying object-oriented database system that allow users to query objects and metaobjects within a single algebra expression are described.>

LIVING IN A LATTICE is presented as a rule-based query language for an object-oriented database model. The model supports complex objects, object identity, and is-a-relationships. The instances are described by object relations, which are functions from a set of objects to value sets and other object sets. The rule language is based on object-terms which provide an access to objects via is-a-relationships. Rules are divided into two classes: object-preserving rules manipulating existing objects and object-generating ones creating objects with properties derived from existing objects. The derived object sets are included in a lattice of object types. Some conditions are given under which the instances of the rule's heads are consistent, i.e., where the properties of the derived objects are functionally determined by the objects.>