DAIS 2001
DAIS 2001 Conference, Krakow, Poland, September 17-19, 2001 International Federation for Information Processing

    Abstracts of Contributed Papers

Liba Svobodova, IBM Research, Zurich

The Intelligent Infrastructure for e-Business


As e-business continues to gain momentum, it also develops into more complex and more dynamic forms, both in the B2C (Business to Consumer) sector, and even more so in the B2B (Business to Business) arena. These trends need to be enabled by increased intelligence and capabilities in the network infrastructure and services, which will evolve into an intelligent infrastructure for e-business. Dynamic e-business will enable very rapid establishment of business partnerships and contracts over the global network, without any prior business relation developed in the traditional way. Online business directories, e-markets, and other kinds of e-intermediaries will be deployed to locate suitable partners who can provide desired products, parts, consulting on a specific issue, or financial investment. Trusted e-intermediaries will also offer services to verify the trustworthiness of potential partners and facilitate the negotiation and closure of a contract. These an other issues will be covered during the talk.

Hani Naguib, George Coulouris, Scott Mitchell

Middleware Support for Context-Aware Multimedia Applications


We describe QoSDREAM, a middleware framework for the construction and management of context-aware multimedia applications. he contributions of QoSDREAM include (1) an novel approach to the handling of location data derived from sensors in the physical world which integrates sensor data from a variety of sources into streams of applicartion-relevant events and (2) a component-based architecture for the construction of real- time multimedia and other context-aware applications. The component architecture supports the construction of application models that are used for quality of service analysis and management purposes. Working distributed applications are derived from the models.

Michael Samulowitz, Florian Michahelles, Claudia Linnhoff-Popien

CAPEUS: An Architecture for Context-Aware Selection and Execution of Services


This paper introduces a comprehensive framework that allows mobile users to access a variety of services provided by their current environment (e.g. print services). Novel to our approach is that selection and execution of services takes into account the user`s current context. Instead of being harassed by useless activities as service browsing or configuration issues, environmental services get seamlessly aligned to the user`s present task. Thus, the challenge is to develop a new service framework that fulfils these demands. The paper proposes a document-based approach; so called Context-Aware Packets (CAPs) contain context constraints and data for describing an entire service request. The core framework, Context-Aware Packets Enabling Ubiquitous Services (CAPEUS), reverts to CAPs for realising context-aware selection and execution of services.

Diego Lopez de Ipina

Sentient Computing for Everyone


Sentient Computing is about giving perception to computing systems, i.e. to enable them to detect, interpret and respond to changing aspects of the user`s context. Inputs from distributed sensors in the environment are collected to maintain a model of the real world and so permit final applications to be reactive to contextual changes. The location attribute of an object`s context is of special interest because it facilitates and makes more natural the interactions between entities and their ubiquitously computerised physical spaces. This interest has resulted in the appearance of several ad hoc hardware-based indoor location technologies offering different levels of location data granularity. However, these indoor positioning systems are costly and difficult to deploy, configure and operate. TRIP is a novel downloadable vision-based software location system that overcomes these limitations. TRIP determines the ID, position and orientation of printable ringcode tags, attached to objects, when placed in the field of view of a camera. Its off-the-shelf hardware requirements, i.e. video cameras and PC processing power, makes the creation of location-aware reactive environments affordable for everyone and everywhere, even at our homes. Nevertheless, to facilitate the creation of smart digitally augmented physical spaces, bringing services to users wherever they are or move to, it is not only necessary to cater for a location system to track user whereabouts but also it is required a middleware infrastructure for user-bound software services activation, movement and destruction. LocALE is a CORBA-based framework that addresses heterogeneous object lifecycle and location control in a network. Some distributed applications combining TRIP sensing capabilities with LocALE`s object activation and migration support are presented to demonstrate our thesis that it is possible to make inexpensive and off-the-shelf Sentient Computing readily available for everyone.

Trevor D Boyd, Peter Robinson

The Active Guide Book


The active guide book is a context-aware information management system that uses a combination of spatial and keyword indexing to retrieve data. The system has three principal components:

  • A new document description language includes facilities for tagging with spatial locations.
  • Retrieval uses two separate indexes ? a segment tree is used for spatial indexing and an inverted file is used for keyword indexing.
  • A user interface allows queries involving keywords and location data to be expressed, and presents their results.

The system has been evaluated with the implementation of an interactive guidebook. The test data was drawn from existing Web pages describing the City of Cambridge in England, which were augmented with spatial information. A GPS system is used to provide the default location information for retrieval, but can be overridden with explicit coordinates.

Dusan Balek, Frantisek Plasil

Software Connectors and their Role in Component Deployment


To support rapid software evolution, it is desirable to construct software systems from reusable components. In this approach, the architecture of a system is described as a collection of components along with the interactions among the se components. Whereas the main system functional blocks are components, the properties of the system also strongly depend on the character of the component interactions. This fact gave birth to the "connector" concept which is an abstraction capturing the nature of these interactions. The problem tackled in this paper is that even though the notion of connectors originates in the earliest papers on software architectures [24, 18], connectors are currently far from being a typical first class entity in the contemporary component-based systems. The authors address the problem by (1) bringing an additional argument in favor of considering connectors as first class entities representing component interactions and by (2) introducing a connector model reflected at all the key stages of an application`s development: ADL specification, deployment, and implementation. By articulating the "deployment anomaly", the paper identifies the role connectors should play when the distribution and deployment of a component-based application is considered. Based on basic connector elements (both predefined and user-defined), a connector can be (at least) partially generated from its ADL generic description and from the information on deployment of the components it connects. This way, the underlying code of a component-based application is advantageously factored into the deployment-neutral part (comprising the "real" application functionality located in components) and deployment- sensitive part (embodied in connectors) which can be regenerated anytime the deployment of the application is modified. As a proof of the concept, a case study is provided, illustrating how the connector model can be integrated into the SOFA/DCUP component model.

Twittie Senivongse, Wuttichai Nanekrangsan

An Extension to a CORBA Trader to Support XML Service Descriptions


Today, access to service descriptions in a CORBA trader is limited to CORBA-based users only. This paper presents a model that facilitates access to CORBA service descriptions from other environments such as World Wide Web. Our work is to extend the functionality of a CORBA trader so that it supports transformation of service type descriptions and service offer descriptions into XML documents, and vice versa. Such transformation is based on our predefined Document Type Descriptions (DTD s) for service types and service offers. XML service descriptions can be used in many ways, e.g. to view details of CORBA services from Web browsers, to do XML search for required services, and to exchange service descriptions between traders.

Xavier Blanc, Marie-Pierre Gervais

On the Construction of Distributed RM-ODP Specifications


LIP6, is association with EDF R&D , proposes a framework that deals with the construction of heterogeneous and distributed specifications. This paper focuses on the part of work devoted to the distribution aspects of a specification, especially the distributed specifications consistency and management. It describes our approach to deal with these two aspects. Regarding the distributed specif ications consistency, we advocate that the modeling language must enable the partitioning of the specification into several pieces and provide means to express the dependencies between them. For this reason, we make use of RM-ODP language as it includes s ome concepts that fit these requirements. However, RM-ODP is not prescriptive enough to be really helpful when elaborating distributed specifications. Thus we propose distributed specifications construction rules in identifying the needed concepts and in defining their usage rules. Concerning the distributed specifications management, we provide a so-called Distributed Specifications Management System (DSMS), that is an RM-ODP specifications repository built in conformance with the MOF and CORBA standards . Such a repository provides facilities to distribute specifications, to link pieces of specifications and to handle them.

Franz J. Hauck, Ulrich Becker, Martin Geier, Erich Meier, Uwe Rastofer, Martin Steckermeier

AspectIX: A Quality-Aware, Object-Based Middleware Architecture


Quality of service is becoming more and more important in distributed systems. Current middleware systems lack of quality-of-service support on the application and on the system level. AspectIX is a CORBA-compliant middleware platform t hat defines a generic application-level quality-of-service interface and an infrastructure for quality implementations. AspectIX is based on a fragmented object model that can provide transparent client-side quality implementations. Quality implementation s can be weaved into functional fragments using a hierarchy of Weavelets which are modular, code-transforming software components.

Heikki Helin, Stefano Campadello

Providing Messaging Interoperability in FIPA Communication Architecture


We describe an on-going technical work done by FIPA standardization organization in the field of agent communication between heterogeneous FIPA agent platforms. The goal of this work is enabling flexible agent communication while provid ing sufficient interoperability. The flexibility is achieved by introducing several options for different layers of communication. Interoperability is assured by messaging gateways translating between incompatible options.

Alexander Schill, Olaf Neumann, Christoph Pohl, Thomas Müller

Architectural Design and Performance Aspects of Developing Applications Based on Middleware


For quite some time now, applications have been designed and developed in various projects of our research group by using middleware. In addition, various middleware products have been evaluated. While one of the projects has dealt with teleteaching/telelearning, the other projects cover the insurance sector. In the teleteaching/telelearning project, an existing client/server system has been converted to EJB. The experiences related to designing the architecture made in that project are a subject of this paper. The various forms of learning (self-learning, cooperation, evaluation) allow to study different characteristics (on-line behavior, asynchronous communication, batch processes) of a middleware platform. The other projects focused on studying the performance of the analyzed servers. Therefore, another subject of this paper will be the results of these studies, along with the characteristics of the analyzed servers other concepts and related work.

G. Koutsoukos, J. Gouveia, L. Andrade, J.L. Fiadeiro

Managing Evolution in Telecommunication Systems


The recent advances in telecommunication technology, namely the wireless networks and the Internet, along with the competition of network operators for offering advanced and different services, are putting increasing pressure for buildi ng telecommunication software systems that are adaptive to new requirements and easily reconfigurable, even in run time. We show how a new modelling primitive ? coordination contract ? that we have developed and applied to other applications domains, can provide an effective solution to this problem. We describe coordination contracts and demonstrate, through several examples, how they can support the evolution of requirements of a telecommunications transaction processing system and of the specifications of the Wireless Application Protocol (WAP) Datagram layer. We also outline a development strategy based on coordination contracts that leads to systems that are more agile in reacting to change.

J. Antonio Garcia-Macias, Franck Rousseau, Gilles Berger-Sabbatel, Leyla Toumi, Andrzej Duda

Mobility Management for Providing QoS in Local Area Wireless Networks


The purpose of this paper is to present our current work on mobility support integrated with QoS mechanisms in a wireless local area network.

Adam Wolisz

The Dual Approach to Internet Charging


José A. Pérez, Rafael Corchuelo, David Ruiz, Miguel Toro

A Framework for Aspect-Oriented Multiparty Coordination


Separation of concerns has been presented as a promising tool to tackle the design of complex systems in which cross--cutting properties that do no fit into the scope of a class must be satisfied. In this paper, we show that interaction amongst a number of objects can also be described separately from functionality by means of the CAL language, and present a framework that provides the infrastructure needed to implement its interaction model.

J. Indulska, S.W. Loke, A. Rakotonirainy, V. Witana, A. Zaslavsky

An Open Architecture for Pervasive Systems


Recent advances in mobile devices create a need for computing architectures and applications which are able to react to environmental changes in order to adapt to the changing context of computation. To date insufficient attention has b een paid to the issues of defining an open component-based architecture which is able to describe complex computational context and handle different types of adaptation for a variety of new and existing pervasive enterprise applications. In this paper an architecture for pervasive enterprise systems is proposed.The architecture uses a component based modelling paradigm and an event-based mechanism which provides significant flexibility in dynamic system configuration and adaptation. The architecture inclu des context management which captures descriptions of complex user, device and application context including enterprise roles and role policies, and allows easy extension by new types of context. The architecture provides an open approach to adaptation wh ich allows easy extension with adaptation mechanisms. In addition, the coordination language used to coordinate system events provides the flexibility needed in pervasive computing applications to support dynamic reconfiguration and a variety of communica tion paradigms.

A.T. van Halteren, G. Fabian, E. Groeneveld

Design and Evaluation of a QoS Provisioning Service


Middleware provides distributed objects with a software infrastructure that offers a set of well-known distribution transparencies. These transparencies enable the rapid introduction of applications for heterogeneous, distributed system s. However, to support guaranteed Quality of Service (QoS) system-specific QoS mechanisms need to be controlled. Accessing the low-level mechanisms directly by applications crosscuts the transparency offered by the middleware and limits portability and in teroperability. The challenge for next-generation middleware is to support application-level QoS requirements, while maintaining the advantages of the distribution transparencies. This paper presents three contributions:

  1. An architecture for a QoS-aware software infrastructure for distributed objects
  2. A framework for a QoS provisioning service (QPS) and
  3. An evaluation of the QPS framework by means of a prototype that supports performance requirements.

Klaus Herrmann, Kurt Geihs

Integrating Mobile Agents and Neural Networks for Proactive Management


The management of modern computer networks and distributed systems comprises big challenges due to the complexity of nowadays network environments. It requires a decentralized approach in order to be efficient, effective, scalable, and flexible. Moreover, it has to be proactive since identifying and preventing problems before they affect users becomes increasingly important. Several research projects have identified mobile agents as a possible solution for decentralized management, whil e others have used neural networks to make predictions and achieve proactiveness. We propose a management system which integrates both technologies to achieve proactiveness in a decentralized fashion. The result is a distributed system that employs mobile and intelligent components. This paper discusses our approach and presents the design and implementation of a prototype application that puts the proposed ideas to practice.

Bart De Decker, Gregory Neven, Frank Piessens, Erik Van Hoeymissen

Second Price Auctions, A Case Study of Secure Distributed Computating


Secure distributed computing addresses the problem of performing a computation with a number of mutually distrustful participants, in such a way that each of the participants has only limited access to the information needed for doing t he computation. Over the past two decades, a number of solutions have been developed. The disadvantage of these cryptographic solutions is the excessive communication overhead they incur. In this paper, we use one of the SDC protocols for one particular a pplication: second price auctions. The case study serves two purposes: we show that SDC protocols can be used for these kind of applications, and secondly, we assess the network overhead and how well these applications scale. To overcome the communication overhead, we use mobile agents and semi-trusted hosts.

Manuel Aguilar Cornejo, Hubert Garavel, Radu Mateescu, Noel de Palma

Specification and Verification of a Dynamic Reconfiguration Protocol for Agent-Based Applications


Dynamic reconfiguration increases the availability of distributed applications, by allowing them to evolve at run- time. This paper deals with the formal specification and model-checking verification of a dynamic reconfiguration protoco l used in industrial, agent-based applications (such as the distributed management of network firewalls available in Bull`s NetWall product). Starting from a reference implementation in JAVA, we produced a specification of the protocol using the Formal De scription Technique LOTOS. We specified a set of temporal logic formulas characterizing the correct behaviour of the protocol, namely safety and liveness requirements for each protocol primitive. Finally, we studied various finite space configurations of the protocol, on which we verified these requirements using the CADP protocol engineering tool set.

Markus Debusmann, Reinhold Kröger

Widening Traditional Management Platforms for Managing CORBA Applications


During the past years, enterprises became more and more dependent on the business processes that are often implemented using CORBA middleware. Todays management platforms ignore the dependency between applications and their middleware, and thus give up valuable information sources that are required for proactive management. In this paper an Integration System is presented by which traditional management platforms are widened for managing CORBA applications. Thus, the investments for an existing management platform are protected. The Integration System consist of an flexible and high available Integration Agent and the Generic Management Interface for querying management-relevant information from CORBA applications.

Lauren A. Tewksbury, Louise Moser, Peter Michael Melliar-Smith

Live Upgrade Techniques for CORBA Applications


The ability to perform live software upgrades is essential to applications that provide critical services and are long- running. Program modifications become increasingly necessary over time as programmer errors and new user requirement s are uncovered. If software is to remain current, it must be upgradable. The Eternal Evolution Manager allows distributed CORBA applications to be upgraded while they continue to provide service. In addition to avoiding unplanned downtime, the Evolution Manager accomplishes the difficult tasks inherent to evolution with minimal help from the application programmer. With our live upgrade techniques, and the underlying fault tolerance of the Eternal System, we can allow applications to run forever.

Gerald Brose

Raccoon - an Infrastructure for Managing Access Control in CORBA


Object-level security management of CORBA applications is not sufficiently supported by current management architectures. This paper presents a language-based approach and an infrastructure for managing fine-grained access control polic ies for CORBA objects at an abstract level.

Peter Herrmann, Lars Wiebusch, Heiko Krumm

Tool-Assisted Security Assessment of Distributed Applications


Abstract Currently increasing distribution, interconnectivity, and mission-criticality of ap-plications entail a rapidly growing gravity of the security issue. In particular that development is also considered by the Object Management G roup which extended the Common Object Request Broker specification by the CORBA security serv-ices. The services support the flexible provision of security features and their em-ployment has to be tailored to the values and threats of a system in order to ensure its sufficient trustworthiness. We relate the corresponding analysis and design tasks of CORBA systems with traditional security analysis, risk assessment, and countermeasure planning as it is in the scope of information system security certi-fica tion standards. We propose a suitable application of the ISO/IEC Common Criteria standard. Since security analysis of complex systems tends to be difficult and error- prone, we combine that proposal with our object-oriented security analysis and modelling approach. It employs object-oriented modelling techniques and tool-assistance in order to facilitate the analysis and assure its quality even in case of extensive systems. After outlining the object-oriented analysis, the CORBA security services, and the Common Criteria we report on the security as-sessment of CORBA based systems and discuss an example application.

Rainer Hauck, Igor Radisic

Service Oriented Application Management - Do Current Techniques Meet the Requirements?


Besides the conclusion of agreements about quality of service (QoS), one of the major prerequisites for a global service market are means to monitor the fulfillment of those agreements. From a user`s perspective, the time needed to comp lete a service transaction represents one of the most critical QoS parameters. As most electronic services are usually based on distributed applications, obviously the same techniques can be used to measure the performance of electronic services as well a s the underlying applications. In recent years several techniques evolved to monitor the application performance. However, the new aspect of service orientation adds relevant new requirements that are to be posed on such solutions. This paper evaluates th e various techniques from a service oriented point of view and presents open research questions.

Dawid Kurzyniec, Vaidy Sunderam

Java Class Loading Techniques in the Harness Metacomputing Framework


Harness is an Java-centric metacomputing system based on a principle of dynamic reconfigurability not only in terms of participating computing resources, but also the capabilities of the virtual machine itself. The central feature of th e system is a plug-in mechanism built upon Java dynamic class loading services enabling integration of new functionality in the run time. In this paper we describe new flexible, framework based Java class loading techniques and their application in the Harness system.

Bodgan Czejdo, Johann Eder, Tadeusz Morzy, Robert Wrembel

Designing and Implementing an Object Relational Data Warehousing System


In this paper we present some of the results achieved while realizing an international research project aiming at the design and development of an Object Relational Data Warehousing System (ORDAWA ). Important goals of the project are t o develop techniques for the integration and consolidation of different external data sources in an object relational data warehouse,the construction and maintenance of materialized relational as well as object oriented views,index structures,query transf ormations and optimizations,and techniques of data mining.The achievements discussed in this paper concern the application of materialized object oriented views in the process of building an object relational data warehouse.

Damir Becarevic, Mark Roantree

Distributed Transactions for ODMG Federated Databases


Global transactions are still an issue for federated database systems. In the IOMPAR project, one of the goals is to develop a transaction protocol for ODMG databases which act as wrappers to information systems in a federation. In this short paper we describe an architecture for trans-porting secure data in a federated database system. Our on-going work involves providing the transaction service which can guarantee global transactions within our architecture.

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