89,603 research outputs found
Software engineering and middleware: a roadmap (Invited talk)
The construction of a large class of distributed systems can be simplified by leveraging middleware, which is layered between network operating systems and application components. Middleware resolves heterogeneity and facilitates communication and coordination of distributed components. Existing middleware products enable software engineers to build systems that are distributed across a local-area network. State-of-the-art middleware research aims to push this boundary towards Internet-scale distribution, adaptive and reconfigurable middleware and middleware for dependable and wireless systems. The challenge for software engineering research is to devise notations, techniques, methods and tools for distributed system construction that systematically build and exploit the capabilities that middleware deliver
A logic programming framework for modeling temporal objects
Published versio
Design Features for the Social Web: The Architecture of Deme
We characterize the "social Web" and argue for several features that are
desirable for users of socially oriented web applications. We describe the
architecture of Deme, a web content management system (WCMS) and extensible
framework, and show how it implements these desired features. We then compare
Deme on our desiderata with other web technologies: traditional HTML, previous
open source WCMSs (illustrated by Drupal), commercial Web 2.0 applications, and
open-source, object-oriented web application frameworks. The analysis suggests
that a WCMS can be well suited to building social websites if it makes more of
the features of object-oriented programming, such as polymorphism, and class
inheritance, available to non-programmers in an accessible vocabulary.Comment: Appeared in Luis Olsina, Oscar Pastor, Daniel Schwabe, Gustavo Rossi,
and Marco Winckler (Editors), Proceedings of the 8th International Workshop
on Web-Oriented Software Technologies (IWWOST 2009), CEUR Workshop
Proceedings, Volume 493, August 2009, pp. 40-51; 12 pages, 2 figures, 1 tabl
Query processing of geometric objects with free form boundarie sin spatial databases
The increasing demand for the use of database systems as an integrating
factor in CAD/CAM applications has necessitated the development of database
systems with appropriate modelling and retrieval capabilities. One essential
problem is the treatment of geometric data which has led to the development of
spatial databases. Unfortunately, most proposals only deal with simple geometric
objects like multidimensional points and rectangles. On the other hand, there has
been a rapid development in the field of representing geometric objects with free
form curves or surfaces, initiated by engineering applications such as mechanical
engineering, aviation or astronautics. Therefore, we propose a concept for the realization
of spatial retrieval operations on geometric objects with free form
boundaries, such as B-spline or Bezier curves, which can easily be integrated in
a database management system. The key concept is the encapsulation of geometric
operations in a so-called query processor. First, this enables the definition of
an interface allowing the integration into the data model and the definition of the
query language of a database system for complex objects. Second, the approach
allows the use of an arbitrary representation of the geometric objects. After a
short description of the query processor, we propose some representations for free
form objects determined by B-spline or Bezier curves. The goal of efficient query
processing in a database environment is achieved using a combination of decomposition
techniques and spatial access methods. Finally, we present some experimental
results indicating that the performance of decomposition techniques is
clearly superior to traditional query processing strategies for geometric objects
with free form boundaries
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