Arne Koschel

Distributed events in active database systems: letting the genie out of the bottle

Abstract Similar to grouping autonomous DBMSs within large-scale distributed, heterogeneous and loosely coupled networks into DBMS federations, active information sources may be grouped into active DBMS federations. The paper claims that as a prerequisite for such federations, event handling must be separated from the members of the federation and concentrated within an independent network component. Two consequences of such a decision are explored in the paper. The construction of suitable wrappers that perform the task of event detection for a large variety of active and passive information sources, and the unbundling of event processing based on ECA rules into a number of individual functions which can then be distributed across the network and configured into event handlers that pursue specific strategies.

Implementation of a Service Oriented Architecture at Deutsche Post MAIL

This paper explains the background and some of our experiences in implementing an integration infrastructure. It describes representative problems of historically grown IT landscapes and shows experience how Deutsche Post MAIL solved this challenge. For that purpose we introduced a business-driven enterprise application architecture and point out its main features and benefits. Afterwards we give an overview on Service Backbone as the technical implementation of the corresponding integration infrastructure. We address IT managers, business architects as well as IT professionals, who want to understand which problems can be solved by establishing a service oriented architecture and how Service Backbone can be used as an integration infrastructure within a SOA [1].

WWW-UDK: a web-based environmental meta-information system

The environmental data catalogue Umweltdatenkatalog UDK is a standard meta-information system for environmental data for use by state authorities and the public. Technically, the UDK consists of a database together with a front-end tailored to the needs of environmental specialists. FZIs contribution has been to develop a front-end that makes the UDK database available using the tools and techniques of the World-Wide Web. Among the features of WWW-UDK are several query modes for the UDK objects and addresses, an environmental thesaurus, on-line access to some of the underlying data (e.g., databases and environmental reports), multilingual query and result forms, and an on-line help system. Currently, several installations of WWW-UDK are used in Austria and in Germany on the Internet and on Intranets. WWW-UDK can be easily integrated into a federation architecture which is based on CORBA, WWW, and Java.

Active information delivery in a CORBA-based distributed information system

Many application areas require the integration of heterogeneous information sources into a coherent distributed information system. With such systems, users frequently need not only be able to access information, but they also have to be notified automatically when new information that is relevant to their work becomes available. For example, an our environmental systems project, a civil servant needs to be informed when a measured air quality parameter exceeds a certain threshhold. Detection of such a critical situation requires subsequent monitoring of several data sources (e.g., a database recording measurement values and a database with limit values). The paper presents an approach for such situation monitoring which is based on CORBA, for the technical integration of heterogeneous systems and on active DBMS-style ECA-rules. In particular, it discusses how ECA-rules can be adopted in a CORBA environment, and describes a CORBA-based system for situation monitoring. The major implementation issues addressed are event detection within autonomous component systems and detection of complex distributed situations.

ECA Functionality in a Distributed Environment

The capabilities of active database systems remain meaningful for distributed applications. However, since the assumptions underlying a distributed active database system differ from those for a centralized active database system, the technical capabilities necessary for supporting active functionality must be revised and extended, and new challenges must be met. In addition, distributed active database systems and distributed rule processing offer new opportunities that make explicit use of the potential of distribution. The goal of this chapter is to provide a systematic overview of the design options for ECA functionality in distributed environments, highlighting the choices from a usage perspective.

High availability: Evaluating open source enterprise service buses

We evaluate three open source enterprise service buses (ESBs) Fuse, Mule and OpenESB, focusing on their support of high availability. Since high availability for the these ESBs relies on transactional Java messaging service (JMS) in a staged event driven architecture (SEDA), we review JMSs first. On this base, we evaluate and rate the ESBs on their support of both stateless and stateful services. We rated Fuse first, followed by Mule and OpenESB.

Applying event-driven architecture to mobile computing

Complex event processing (CEP) has been an area of intensive research in recent years. Similarly, mobile devices such as smartphones, tablets and laptops are widespread nowadays. Consequently, the integration of CEP into mobile computing is a natural idea. In this paper, we present MetaXA, an event-driven architecture (EDA) with CEP specifically designed for mobile devices, along with its application scenarios in mobile computing: notification distribution and theft detection. Among the main enhancements of MetaXA over previously published work are enabling CEP on mobile devices and leveraging a lightweight yet still platform-independent communication protocol (viz., XMPP). In addition, MetaXA features real-time communication patterns and a publish-subscribe mechanism. MetaXA is implemented on different mobile platforms: Android and Windows Phone.

Basistechnologien für die Entwicklung von Internet-Prtalen

Internet-Portale sind personalisierte Einstiegsseiten im Internet, die verschiedenartigste Ziele verfolgen. Wir stellen zunachst typische Arten von Internet-Portalen kurz vor. Das derzeit aktuelle Schlagwort Portal bezeichnet personalisierbare Internet-Zugange zu Informationsdiensten. Hierbei werden unterschiedliche Anwendungen mit diesem Schlagwort bedacht, die z.B. von Eingangspforten fur das Massenpublikum uber Informationskanale fur Spezialgebiete bis hin zu Business-to-Business Vertriebswegen reichen. Daraus ergeben sich charakteristische funktionale Anforderungen an solche Portale. Nicht-funktionale Anforderungen betreffen dann Qualitatseigenschaften, wie zum Beispiel Zugriffssicherheit, Netzwerksicherheit, Ausfuhrungsgeschwindigkeit, Ergsonomie und Konformitat mit Standards. Aus den funktionalen und nicht- funktionalen Anforderungen konnen typische Systemkomponenten von Internet- Portalen abgeleitet werden. Zwei kommerziell verfugbare Basisprodukte zur Entwicklung von Internet-Portalen werden vorgestellt und es wird skizziert, wie diese Produkte die Anforderungen erfullen sollen. Ein Schwerpunkt dieses Kurzbeitrags ist die Prasentation eines Uberblicks uber verschiedene Aspekte des Entwurfs und der Implementierung von Internet-Portalen.

Asynchronous messaging for OSGi

OSGi is a popular Java-based platform, which has its roots in the area of embedded systems. However, nowadays it is used more and more in enterprise systems. To fit this new application area, OSGi has recently been extended with the Remote Services specification. This specification enables distribution, which OSGi was previously lacking. However, the specification provides means for synchronous communication only and leaves out asynchronous communication. As an attempt to fill a gap in this field, we propose, implement and evaluate an approach for the integration of asynchronous messaging into OSGi.

Think Large, Act Small: An Approach to Web Services for Embedded Systems Based on the OSGi Framework

Traditionally, web services were used in large distributed systems. In this paper, we propose an approach to using web services in embedded systems, which have small memory footprints. At the heart of our approach lay: (1) the use of Apache CXF to extend the OSGi framework with distribution; and (2) the adaption of Apache CXF to embedded system platforms such as Java Standard Edition Embedded, JamVM and Java Micro Edition. We give examples of possible application of our approach in a car tracking system and an advertising system for car drivers.