Both object orientation and parallelism are modern programming paradigms which have gained much popularity in the last 10-15 years. Object orientation raises hopes for increased productivity of software generation and maintenance methods. Parallelism can serve to structure a problem but also promises faster program execution. The two areas of computing science in which these paradigms play the most prominent role are programming languages and databases. In programming languages, one can take an academic approach with a primary focus on the generality of the semantics of the language constructs which support the respective paradigm. In databases, one is willing to restrict the power of the constructs in the interest of increased efficiency. Inter- and intra-object parallelism have received an increasing amount of attention in the last few years by researchers in the area of object- oriented programming. At first glance, an object is very similar to a process which offers services to other processes and demands services from them. It has, however, transpired that object-oriented concepts cause problems when combined with parallelism. In programming languages, the introduction of parallelism and the synchronization constraints it brings with it can get in the way of code reusability. In databases, the combination of object orientation and parallelism requires, for example, a generalization of the transaction model, new approaches to the specification of information systems, an implementation model of object communication, and the design of an overall system architecture. There has been insufficient communication between researchers in programming languages and in databases on these issues. Object Orientation with Parallelism and Persistence grew out of a Dagstuhl Seminar of the same title in April 1995 whose goal it was to put the new research area object orientation with parallelism' on an interdisciplinary basis. Object Orientation with Parallelism and Persistence will be of interest to researchers and professionals working in software engineering, programming languages, and database systems.

Newer computingareas like peer-to-peer,grid, and service-orientedcomputing provide a number of opportunities and challenges for architectures of future digital libraries. Peer-to-peer data management allows for loosely coupled integration of information services and sharing of information such as recommendations and annotations. Grid computing middleware is needed because certain services within digital libraries are complex and computationally intensive, e.g., extraction of features in multimedia d- uments to support content-based similarity search or for information mining in b- medical data. The service-orientation provides mechanisms to describe the semantics and usage of information services and to combine services into work?ow processes for sophisticated search and maintenance of dependencies. Elements of all three directions should be combined in a synthesis for future digital libraries architectures. This volume contains selected and revised papers from the Sixth Thematic Wo- shop of the EU Network of ExcellenceDELOS on Digital Library Architectures,which washeldin S. MargheritadiPula (Cagliari),Italy,24-25June2004.Thisworkshopwas co-located with the 12th Italian Symposium on Advanced Database Systems (SEBD 2004) and organizedjointly by the DELOS Network of Excellence and the Department ofInformationEngineeringoftheUniversityofPadua,Italy. DELOS(http://www.delos.

Recently, we have seen a steep increase in the popularity and adoption of XML, in areas such as traditional databases, e-business, the scientific environment, and on the web. Querying XML documents and data efficiently is a challenging issue; this book approaches search on XML data by combining content-based methods from information retrieval and structure-based XML query methods and presents the following parts: applications, query languages, retrieval models, implementing intelligent XML systems, and evaluation.

To appreciate the book, basic knowledge of traditional database technology, information retrieval, and XML is needed. The book is ideally suited for courses or seminars at the graduate level as well as for education of research and development professionals working on Web applications, digital libraries, database systems, and information retrieval.

These proceedings collect the papers selected for the 2nd International Conf- ence on Interoperating GeographicInformationSystems held in Zur .. ich, Switz- land, 10-12 March, 1999. Interoperabilityhasbecomeanissueinmanyareasofinformationtechnology in the last decade. Computers are used everywhere, and there is an increasing need to share various types of resources such as data and services. This is es- ciallytrueinthecontextofspatialinformation.Spatialdatahavebeencollected, digitized and stored in many di?erent and di?ering repositories. Computer so- ware has been developed to manage, analyse and visualize spatial information. Producing such data and software has become an important business oppor- nity. In everydayspatialinformation handling in manyorganisationsand o?ces, however, interoperability is far from being a matter of fact. Incompatibilities in data formats, software products, spatial conceptions, quality standards, and models of the world continue to create as synchronicity among constituent parts of operating spatial systems. As a follow-upto the ?rst InternationalConference on Interoperating Geographic Information Systems held 1997 in Santa Barbara, California, the Interop'99 tries to provide a scienti? c platform for researchers in this area. Theinternationalprogramcommitteecarefullyselected22papersforpres- tation at the conference and publication in this volume. Additionally, this v- ume contains three invited contributions by Gio Wiederhold, Adrian Cuthbert and Gun .. ther Landgraf. Every paper was sent to three members of the program committee and other experts for review. The reviews resulted in a three-day single-track conference program that left some room for a few half-day tutorials on various topics regarding GIS interoperability.

This book constitutes the refereed proceedings of the 6th International Conference on Extending Database Technology, EDBT '98, held in Valencia, Spain, in March 1998. The 32 revised full papers presented together with one invited keynote were selected from a total of 191 submissions. The book is divided in sections on similarity search and indexing, query optimization on the Web, Algorithms for data mining, modelling in OLAP, query processing and storage management, aggregation and summary data, object-oriented and active databases, view maintenance and integrity, databases and the Web, workflow and scientific databases.

Both object orientation and parallelism are modern programming paradigms which have gained much popularity in the last 10-15 years. Object orientation raises hopes for increased productivity of software generation and maintenance methods. Parallelism can serve to structure a problem but also promises faster program execution. The two areas of computing science in which these paradigms play the most prominent role are programming languages and databases. In programming languages, one can take an academic approach with a primary focus on the generality of the semantics of the language constructs which support the respective paradigm. In databases, one is willing to restrict the power of the constructs in the interest of increased efficiency. Inter- and intra-object parallelism have received an increasing amount of attention in the last few years by researchers in the area of object- oriented programming. At first glance, an object is very similar to a process which offers services to other processes and demands services from them. It has, however, transpired that object-oriented concepts cause problems when combined with parallelism. In programming languages, the introduction of parallelism and the synchronization constraints it brings with it can get in the way of code reusability. In databases, the combination of object orientation and parallelism requires, for example, a generalization of the transaction model, new approaches to the specification of information systems, an implementation model of object communication, and the design of an overall system architecture. There has been insufficient communication between researchers in programming languages and in databases on these issues. Object Orientation with Parallelism and Persistence grew out of a Dagstuhl Seminar of the same title in April 1995 whose goal it was to put the new research area object orientation with parallelism' on an interdisciplinary basis. Object Orientation with Parallelism and Persistence will be of interest to researchers and professionals working in software engineering, programming languages, and database systems.

This volume constitutes the proceedings of the International Workshop on Advanced Research in Geographic Information Systems, IGIS '94, held in Ascona, Switzerland in February/March 1994.
The 28 carefully refereed and revised papers address all current aspects of GIS research and their advanced applications to spatial and environmental data engineering. Among the topics covered are GIS theory, spatial databases, spatial data structures, environmental modelling and control, data modelling, object-orientation, pattern recognition, and optimization. In addition, software and non-commercial as well as commercial GIS are analysed.

Spatial database management has become an important subarea of current database research. Research in this area is often characterized by interdisciplinary cooperation: computer scientists work with geographers andenvironmental scientists to provide better access to spatial databases of steadily increasing size. After the First Symposium on Large Spatial Databases (SSD '89) was held in Santa Barbara, California, in 1989 (and its proceedings published as Volume 409 of this series), a second symposium (SSD'91) was held in Zurich, Switzerland. This proceedings volume contains the papers presented at SSD '91. Topics include spatial data models and access methods, performance studies, geometric algorithms, spatial query languages and user interfaces, geographic information systems, and object-oriented techniques.

This volume was primarily intended to present selected papers from the workshop on Theory and Applications of Nested Relations and Complex Objects, held in Darmstadt, FRG, from April 6-8, 1987. Other papers were solicited in order to provide a picture of the field as general as possible. Research on nested relations and complex objects originates in the late seventies. The motivation was to obtain data models and systems which would provide support for so-called complex objects or molecular structures, i.e., for hierarchically organized data, thereby overcoming severe shortcomings of the relational model. This theme of research is now maturing. Systems based on those ideas are beginning to be available. Languages of various natures (algebras, calculi, graphical, logic-oriented) have been designed and a theory is slowly emerging. Finally, new developments in database technology and research are incorporating features of models involving complex objects. A variety of approaches is represented in this volume. The first three papers give overviews of major pioneering implementation efforts. The fourth paper is devoted to the important issue of implementation of storage structures. The next three papers propose excursions in the foundations of nested relations and complex objects. The following six contributions are all devoted to modeling of complex objects. The area of database design is represented by the last four papers.