Abstract:
Integrating heterogeneous data sources, which are distributed over
highly dynamic computer networks, is one of the crucial challenges at
the current evolutionary stage of Information Technology
infrastructures. Large enterprises, business organizations,
e-government systems, and, in short, any kind of internetworking
community, need today an integrated and virtualized access to
distributed information resources, which grow in number, kind, and
complexity.
Several papers published in the last decades point out the need for a
formal approach to data integration. Most of them, however, refer to
an architecture based on a global schema and a set of sources. The
sources contain the real data, while the global schema provides a
reconciled, integrated, and virtual view of the underlying sources.
As observed in several contexts, this centralized achitecture is not
the best choice for supporting data integration, cooperation and
coordination in highly dynamic computer networks. A more appealing
architecture is the one based on peer-to-peer systems. In these
systems every peer acts as both client and server, and provides part
of the overall information available from a distributed environment,
without relying on a single global view.
In this talk, we review the work done for rigorously defining
centralized data integration systems, and then we focus on
peer-to-peer data integration, with the aim of singling out the
principles that should form the basis for data integration in this
architecture. Particular emphasis is given to the problem of
assigning formal semantics to peer-to-peer data integration systems.
We discuss two different methods for defining such a semantics, and we
compare them with respect to the above mentioned principles.
Walter Didimo:
Spine and Radial Drawings of Graphs
Abstract:
Graph drawing is devoted to the design of models and algorithms for the
visualization of graphs, with the purpose of computing pleasant and
readable drawings. This is typically done by taking into account the
optimization of important aesthetic requirements, like for example the
number of edge crossings, the number of bends on edges, and the area of
the drawing.
Among the wide set of graph drawing conventions, layered drawings have a
long tradition; they require that the vertices of the graph are placed on
geometric "layers". Spine and radial drawings of graphs are layered
drawings such that the layers are parallel straight lines and concentric
circles, respectively. They are relevant both in traditional and in
emerging application fields, which include computer and social networks
analysis, cybergeography, software engineering, and bioinformatics.
In this talk recent advances on crossing-free spine and radial drawings of
graphs are presented, and the relationships between the number of layers and
the number of bends in these drawings are discussed. From the investigation of
these relationships, several intriguing theoretical and practical open problems
arise.
Hans-Jörg Schek:
The Hyperdatabase Network New Middleware for
Searching and Maintaining the Information Space
Abstract:
The hyperdatabase network, a project at ETH Zurich since 1998, is a new
middleware for the information space and includes new multi-object
multi-feature search facilities for multimedia objects. It applies database
technology at the level of services and combines peer-to-peer, grid, and
service-oriented architectures.
Thomas Seidmann:
Architecture of a Business Framework for the .NET Platform and Open Source Environments
Abstract:
This paper contains a description of the architecture and
components of a software framework for building enterprise style
applications based on the .NET platform. The process and
achieved results of porting this business framework to an open
source platform based on GNU/Linux/Mono is described as well.
Laszlo Szekely:
Progress on Crossing Number Problems
Abstract:
Crossing numbers have drawn much attention in the last couple of years
and several surveys and bibliographies have been published.
The present survey tries to give pointers to some of the most significant
recent developments and identifies computational challenges.
