Abstract: Enterprise roles define the duties and responsibilities of the individuals which are assigned to them. This paper introduces a framework for the management of large distributed systems which makes use of the concepts developed in role theory. Our concept of a role groups the specifications of management policies which define the rights and duties corresponding to that role. Individuals may then be assigned to or withdrawn from a role, to enable rapid and flexible organisational change, without altering the specification of the policies. We extend this role concept to include relationships as means of specifying required interactions, duties and rights between related roles. Organisations may contain large numbers of similar roles with multiple relationships between them, so there is a need for reuse of specifications. Role and relationship classes permit multiple instantiation and inheritance used for incremental extension of the organisational structure with minimal specification effort. We also briefly examine consistency and auditing issues related to this role framework.

Abstract: A new framework is required for the consistent and coordinated construction and configuration of multimedia components across heterogeneous distributed object environments. The paper presents a distributed multimedia component architecture which extends beyond the current well developed distributed object models, such as the Common Object Request Broker Architecture (CORBA) and the Microsoft Distributed Component Object Model (DCOM) models, to support additional mechanisms and abstractions for continuous media stream interactions aimed particularly at distributed multimedia applications. This framework additionally includes distributed resource management and dynamic Quality of Service (QoS) monitoring and adaptation in order to support the implementation of complex distributed multimedia applications over heterogeneous networks and end-systems. The multimedia component architecture (MCA) presented is being used as the middleware component of a comprehensive resource management architecture for distributed applications (Waddington, 1997).

Abstract: Issues of workflow systems adaptability and evolution capability are discussed from two perspectives, namely design and evolution of workflow systems from a continuous software engineering perspective as well as redesign and runtime on-the-fly modifications of workflow models from an application perspective. Special attention is paid to a suitable infrastructure support for designing more configurable and adaptive workflow systems. A new workflow language, called Higher-Order Object Nets (HOON), is introduced. The intended uses of HOON are, on one side, to directly describe real-world business processes, and on the other side, to serve as a build-time composition model and a run-time overall control skeleton of the underlying software components that support individual business activities. On the basis of HOON and CORBA, a layered, framework-based and generic system architecture is presented.

Abstract: The paper describes an environment for interactive configuration management of the software components comprising a distributed enterprise application. The environment permits one or more managers to view and modify the structure of components in terms of component instances, their allocation to hardware nodes and the bindings between their interfaces. The graphical management is based upon the Darwin configuration language which can be used to create the initial system. It supports hierarchical composition of CORBA components to form a composite distributed application or service. When this structure has been modified interactively, a persistent specification of the configuration can be saved to backing store. This can be used to determine unreachable or failed components and, if necessary, to recreate them. The configuration management environment is integrated into an overall domain-oriented platform for enterprise management. The paper illustrates the use of the management system in terms of a simple banking example, and outlines the implementation based on a CORBA platform.

Abstract: Reuse of software components available in open distributed systems is a promising approach for efficient development of complex distributed applications. In open distributed systems, type mechanisms are used both to find appropriate external software components and also to guarantee that their respective interfaces match. Furthermore, a type manager allows application developers to interactively browse existing functionality and enables the automatic mediation of compatible software components at run-time. This paper presents a uniform view for handling the functionality offered by software components regardless of context-specific aspects and a framework that allows for the automatic deduction of different flavors of compatibility relations. Finally, we describe our current type management prototype implementation.

Abstract: Much of today's software development involves reengineering legacy applications, but the bulk of research and tools address new software development. The Distributed Object Management Integration System (DOMIS, 1993-96) project investigated how legacy applications can be incrementally modified, or migrated, by using distributed object management (DOM) technology. The paper describes a methodology for such migration using DOM technology.

Abstract: Traditional systems development methodologies are not focused on the development of distributed systems. However, efforts to address these problems are going on within OMG, with the focus to standardise a meta-model for analysis and design methodologies. The initial submissions converged into a meta-model of Unified Modeling Language (UML), which is emerging as the standard from OMG. This meta-model defines a set of modelling elements that can be used by different methodologies supporting different domains. The authors investigate, in the context of open distributed processing (ODP), the support for the modelling of Quality of Service (QoS) in UML when modelling distributed multimedia applications. In the context of OMG's architecture, they propose some extensions based on the current version of UML to support QoS and multimedia applications. They use a car computer system with Global Positioning System (GPS) support as an example.

Abstract: Current approaches for service mediation, such as trading, do not provide means for a long-term binding of services. They do not ensure that certain services are provided and that the desired service properties are fulfilled. Moreover, a server may withdraw a service offer at any time. For the integration of external services into an enterprise internal service market, it is necessary to guarantee the permanent availability of the services with desired properties and to sustain these properties. This requires that the technical relationship between the service provider and the customer has to be extended by commercial and legal ones. In this paper, we introduce the concept of virtual private resources to enable long-term relationships between the customer and the provider of a service. Virtual private resources are services that can be bound by contract for a longer period of time. They can be considered as private ones, although the physical resources that provide the service may change or be shared with other customers. We introduce the basics of the approach and present a possible architecture for implementing virtual private resources. Finally, we give an example for the application of virtual private resources to implement a traffic information system.

Abstract: A network management system (NMS) has been built using distributed object technology and a four-layered architecture with device model objects. This NetKeeper NMS, which is built on a distributed object platform, has improved scalability and fault tolerance, and can be customized easily. It can thus be used to manage enterprise networks, which consist of a huge number of multi-vendor network devices and have original management policies. NetKeeper is being used in a commercial Internet service provider's network and in several LANs.

Abstract: This paper reports on applying the ODP enterprise viewpoint in the domain of tele-education. The work is conducted as part of a research activity that aims at designing a tele-education system to support planning, execution and evaluation of dynamic distributed educational processes. We explore the ODP enterprise viewpoint as a basis for communication and co-operation between educational scientists and ODP systems designers involved in the design process. Our application of the enterprise viewpoint involves four main steps. First, an educational language is proposed to describe educational processes in generic terms. Second, a set of appropriate enterprise language concepts is selected. Third, a relationship is established between the educational language and enterprise language concepts. Fourth, an educational process is modelled in terms of an entity-oriented model and a behaviour-oriented model. It is hoped that the experience gained in this exercise will provide useful feedback to both the educational and ODP communities.

Abstract: The Compact Muon Solenoid (CMS) high energy physics experiment will comprise several large high resolution detectors each of which will be constructed out of over a million precision parts and will be produced and assembled during the next decade by specialised centres distributed world-wide. Each constituent part of each detector must be accurately measured and tested locally prior to its ultimate assembly and integration in the experimental area at CERN. The CRISTAL (Concurrent Repositories and Information System for Tracking Assembly and production Lifecycles) system is a prototype being developed to monitor and control the production and assembly process of 110000 lead tungstate (PbWO/sub 4/) mono-crystals, and their associated fast electronics, to be installed in the CMS Electromagnetic Calorimeter (ECAL). The software will be generic in design and hence reusable for other CMS detector groups. The paper discusses the distributed computing problems and design issues posed by this project.

Abstract: This paper analyses the information brokerage service business environment and proposes a suitable enterprise model. The model definition was made according to the ODP enterprise viewpoint syntax and semantics and provides a modular framework within which the various components of the system are functioning for supporting its potential users in identifying and performing their tasks. The enterprise specification of the brokerage service starts from the definition of the actors involved in the service provisioning scenarios (End-Users, Brokerage Service Provider Retailer, Content Providers, Information Service Providers, Network Providers), their respective domains, their roles and relationships. A set of Brokerage Service scenarios is presented using the concepts defined in the proposed model.

Abstract: Online transaction processing (OLTP) applications have special requirements in the areas of scalability and performance. Mincom currently markets a successful product, MIMS (Mincom Information Management System), which is a large, integrated OLTP system consisting of about 16,000 KLOC (kilo-lines of code), mostly COBOL. Our research group is developing prototypes in preparation for migrating MIMS into a distributed architecture. CORBA is our current research focus. This paper examines the limitations of CORBA for current use in enterprise OLTP development. Major concerns include: the lack of a standardised persistence interface for use with major database vendors; the immaturity of the Object Transaction Service and Concurrency Service; the lack of integrated workflow solutions; scalability and robustness; the lack of performance monitoring tools; and poor enterprise development environments. We are optimistic that vendors and the OMG will eventually solve these problems, but feel that it may be a few years before workable commercial solutions are in place.

Abstract: Telecooperation receives increasing importance in a globalized information and work infrastructure. Among others, teleconferencing and workflow management are technological areas being studied and developed to support telecooperation scenarios. i.e. real-time collaboration tasks are being supported by teleconferencing systems, asynchronous tasks are being supported by workflow management systems. An integrated telecooperation framework for both approaches is described, which uses a conference broker to couple both system types. The close coupling, however, is not transparent with respect to the actual instances of used systems. This lack of service selection transparency also results in a lack of location transparency. Thus, the authors extend their framework by a trading service. Workflow modules act as the importers of teleconferencing services being exported by conference modules. A distributed trading service mediates between service offers and service requests. The trader is self-sufficient as it does not require any distributed platform, such as CORBA or DCE. It may be deployed in a standard Internet infrastructure.

Abstract: Enterprise level QoS issues are discussed, from which QoS evolution paths are derived. Service level QoS issues are identified and they have been studied as apart of service quality issues in TINA service architecture. TINA stream binding and its role in the TINA QoS framework are presented. A soft guarantee of stream quality is proposed, which does not require strict resource reservation. Soft guarantee concept combined with TINA stream binding architecture supports progressive evolution of service quality.

Abstract: The Internet and the World Wide Web (WWW) have elicited the explosion of accessible data repositories. Because high connectivity is now a reality, the challenge has been to take advantage of it to enable data sharing in a cost-effective way. Any proposed architecture would have to allow dynamic couplings of heterogeneous databases based on their content and interest. The authors propose an implementation using CORBA and Web technologies as a distributed infrastructure and platform to support the dynamic interconnection of heterogeneous and autonomous databases on the Web.

Abstract: IT systems play an ever increasing role in business, commerce, government and services, and can be involved in making decisions that carry enormous implications. This implies that these machines carry responsibility for those decisions and for their outcomes. This paper considers the implications of such "machine responsibility" both for the enterprise concerned and for the IT system, and how the issues involved can be addressed through enterprise modelling using the Enterprise Language of the Reference Model for Open Distributed Processing (RM-ODP) as part of an overall system specification approach.

Abstract: The Component Object Model (COM) (and by definition, DCOM) is the only component system where there is a significant market for commercially available components. This paper discusses the elements of COM's design that have all contributed to making COM such a viable commercial reality: black box-encapsulation, interfaces, interface immutability, multiple interfaces, and location transparency.

Abstract: Presents experiences made during the development of an application framework supporting the design, implementation and deployment of telecommunication services. This paper introduces the concepts of a TINA-C (Telecommunications Information Networking Architecture Consortium) compliant environment as an example for a framework in an enterprise-specific vertical application domain. The paper shows the necessity to define a supporting engineering framework including a set of related design patterns that allow one to design application frameworks in a technology-independent way. It presents the major concepts of a related middleware that has been designed as an ODP (Open Distributed Processing) compliant distributed processing environment and that has been implemented in a heterogeneous CORBA 2 (Common Object Request Broker Architecture) environment. The presented work is a part of the research and development program of GMD FOKUS and builds the core of the Y middleware.

Abstract: In this article we propose workflow techniques such as FUNSOFT for the specification of ODP Enterprise Models. Workflow-orientation as one of the most popular management paradigms and object-orientation as the state of the art software development paradigm are integrated in the ODP framework. Our example is related to our experience in the air traffic control application domain and will demonstrate how a workflow related development perspective embedded in the ODP framework can improve the system integration on one hand and will guarantee user participation at the same time. The properties of FUNSOFT nets are compared to the elements of the ODP enterprise language and an interpretation of FUNSOFT nets in the ODP framework is proposed. We demonstrate how workflow-orientation can be used for the harmonisation of business processes in the air traffic control domain.

Abstract: Current approaches for service mediation, such as trading, do not provide means for a long-term binding of services. They do not ensure that certain services are provided and that the desired service properties are fulfilled. Moreover, a server may withdraw a service offer at any time. For the integration of external services into an enterprise internal service market, it is necessary to guarantee the permanent availability of the services with desired properties and to sustain these properties. This requires that the technical relationship between service provider and customer has to be extended by commercial and legal ones. In this paper, we introduce the concept of Virtual Private Resources to enable long-term relationships between the customer and the provider of a service. Virtual Private Resources are services that can be bound by contract for a longer period of time. They can be considered as private ones, although the physical resources that provide the service may change or be shared with other customers. We introduce the basics of the approach and present a possible architecture for implementing Virtual Private Resources. Finally, we give an example for the application of Virtual Private Resources to implement a traffic information system.

Abstract: This paper introduces an object-oriented approach to the integrated modeling of organizations, and their information systems in a distributed context. The approach is based on the OOram role modeling methodology concepts and tool. In the proposed approach organization modeling is done at the enterprise level of abstraction and both reverse and forward engineering are consistently supported. Distribution is modeled, at both the organization and information system levels of abstraction, in an integrated way. Traceability is supported between all models.

Abstract: The paper presents the development of a distributed architecture for the factory automation domain by applying the object-oriented domain engineering (OODE) method. The first part of the paper talks about extending formally defined object-oriented analysis and design (OOA&D) methods with domain engineering (DE) concepts. It defines the resulting OODE workflow, deliverables, and development cycle. The goal of the OODE workflow is to produce a generic object-oriented (OO) model, which spans a domain and from this model a domain framework for the rapid assembly of applications using a distributed object architecture. The second part of the paper presents case studies of OODE for two factory domain frameworks: machine monitoring system and data collection. The paper presents some findings on merging the two factory domain projects into an overall factory architecture. Then it concludes with a look at incorporating knowledge acquisition techniques to improve the OODE workflow.

Abstract: Presents an integrated approach (practices) to object-oriented distributed application development that covers all phases of software development: requirements capture, analysis, design (structural and behavioural), simulation and targeting to CORBA-based distributed processing environments. We focus on a code generation strategy that addresses and supports all phases of the practices. We highlight code generation objectives including support for multiple paths through the practices, reuse of existing tool-sets and support for traceability. We describe one path in more detail and present an example of design-OMT-to-SDL translation based on labelling in OMT. We describe two development environments used in the project and analyse them with respect to their support for our code generation objectives. Our tool adaptation work is addressing identified weaknesses. This includes an SDL-to-Java/CORBA code generator, the generation of CORBA-to-SDL-mapping C++ wrappers for C code generated by existing tools and the use of CORBA to integrate development tools and support traceability.

Abstract: A common problem in distributed systems is the selection of a particular service instance from a set of possible services. In this paper, we identify the kinds of information required to select services within enterprise distributed systems and present a flexible mechanism for selecting services. This mechanism enables clients to build complex queries that are able to utilise script-based interaction with service instances. The use of scripts allows the selection of particular services based on their internal state and permits services to tailor their responses based on the particular client.

Abstract: A communication infrastructure for enterprise information systems requires not only interoperability but also high reliability. An effective way to allow for differences in operation time and administrative policies is to provide a nonblocking communication interface. In the CORBA 2.0 specification, however, non-blocking communication is not defined as a delivery reliability aspect. The OMG is working on standards for a messaging service, and has taken up reliability as one QoS property. This does not mean, however, that reliability will always be defined as a function when ORB is implemented. It is therefore important to realize reliability on CORBA at the application level. The paper proposes and implements a communication method whereby the client is not blocked while communicating, and a method for realizing this as an application on CORBA. It then evaluates the implemented system and shows the effectiveness of the proposed method for enterprise information systems.

Abstract: One of the most important CORBA services defined by the OMG is the Object Transaction Service (OTS) which augments the CORBA object model with the notion of distributed transactions. The implementation design of the OTS is critical for the service to be really effective for applications. A good design suggests that the OTS should be part of the ORB (object request broker) itself rather than on top of it like normal CORBA objects. In this paper, we highlight the design implementation of the OTS within the Orbix product and describe how the interposition of transaction objects can be achieved by exploiting the hooks provided by the underlying ORB.

Abstract: Interworking traders allow their clients' requests and their servers' advertisements to go across the boundaries of trading communities. Interworking is accomplished via trader links. The OMG (Object Management Group) and the ISO ODP (Open Distributed Processing) Committee have published a paper (OMG RFP5 Submission, "Trading Object Service", OMG Document orbos/96-06-07) which specifies asymmetrical links for trader interworking. Symmetrical links, however, provide more quality of service than asymmetrical links, and thus facilitate trader interworking significantly. This paper discusses both symmetrical and asymmetrical links and presents a federation manager which solves most of the problems caused by asymmetrical links.

Abstract: Previous work on long-running transactions for multi-database environments relaxes the isolation requirement of conventional ACID transactions. However, most of that work does not provide mechanisms to explicitly enforce isolation. This paper proposes a framework in which long-running transactions can specify global predicate-based locks to enforce limited forms of isolation between selected transactions. The framework appears to be especially useful in contexts where there is a class of transactions with stringent deadlines, and another class of transactions making multi-database updates that do not have stringent deadlines. This report motivates and presents the framework, and illustrates its use in connection with maintaining inter-database constraints.