Distributed Object Computing Research Articles

Foundational MDA Patterns for Service-Oriented Computing .

As the foundation of EDI, B2C and B2B, distributed comput- ing is a key enabler for today's enterprises and will become even more important with the advent of cloud computing on the one hand and an ever more agile work organization on the other hand. Whilst the rapid evolution of distributed computing technologies in the last three decades has delivered a rich set of platforms and paradigms for building robust enterprise systems, it has also left a legacy of unresolved problems includ- ing fundamental inconsistencies between the concepts of the two leading distributed computing paradigms, i.e., distributed object computing and service-oriented architecture. Equally important, there is a growing need to lower the complexities and barriers involved in developing client appli- cations, which range from large scale business applications and business processes to laptop programs and small apps on mobile devices. In this article, we present a unified conceptual framework for service-oriented computing based on the proven MDA (Model Driven Architecture) ter- minology stack. With the conceptual framework we consolidate, and give semantics to, core concepts of service-oriented computing and provide a set of foundational model transformation patterns that map between the presented concepts and further clarify practical service-oriented comput- ing scenarios. Finally, we show how the developed framework perfectly fits to the OSM (Orthographical Software Modeling) approach.

Analytical Comparison of Aspectized Service Oriented and Distributed Objects

Distributed Object Computing is a paradigm that allows objects to be distributed across a heterogeneous network and allows each of the components to interoperate as a unified whole. The evolution of a revolutionary programming paradigm that promises to have a profound effect on the way we interact with computers, people and places is well known as Aspect Oriented Programming. Middleware platforms, such as RMI, CORBA, DCOM, J2EE and .NET platform, offer abstractions for the complex distributed environment. Distributed middleware are difficult to build and implement because the distributed frameworks impose a large code overhead due to the specific distributed systems programming conventions. In this paper we implement Aspects with distributed objects technologies and web services and compare the implementation behavior of distributed systems’ programming concepts in comparison to the design of web services based distributed middleware framework. The research challenge involves firstly removing crosscutting concerns by modularizing into separate units named Aspects and secondly implementation and comparison of the three major technologies in the field of distributed systems RMI, CORBA and Web Services.

Ontology-based process model for business architecture of a virtual enterprise

As new collaborative business models emerge, considerable research is being carried out on Virtual Enterprise (VE) as an alternative to secure competition. To operate a VE, a common framework that must be shared between participants is needed to implement a seamless business process. This paper focuses on an ontology-based process model that provides a common semantic and communication protocol. The suggested process model has a single integrated meta-model that describes the internal and intra business process of a VE. The internal process is the formal process of each business partner and is described using the Collaborative Component Architecture (CCA) of Enterprise Distributed Object Computing (EDOC). On the other hand, the intra process is a collaborative process that can be modified by the business scenario and is described using a Role Activity Diagram (RAD). The suggested process model is applied for the collaborative design chain process of the automotive-part industry as a case study.

A collaborative design framework for the Korean automotive parts industry

In the automotive industry, although small enterprises that supply car parts participate in the design phase of new car development, they do not communicate with each other for developing parts or modules because of the lack of a common communication protocol. In order to provide solutions to such problems, there has been an emergence of collaboration solutions among participants. Moreover, collaborative product lifecycle management (CPLM) is suggested as an alternative for providing such collaboration solutions. In order to develop CPLM, a framework that supports the understanding and sharing of business processes across business boundaries is necessary. Such a framework includes a reference model, business process model, and business process. The reference model explains the business domain, and it must be shared among participants for a common communication purpose. The business process model describes the collaborative design process, which can be defined by common principles in a meta-model. This paper suggests a new reference model for the design chain in the Korean automotive parts industry. Under a collaborative environment, the design process of the reference model may be classified into the mechanical and human-driven processes. In order to define both process types, a new integrated process model that combines the Component Collaboration Architecture (CCA) model of Enterprise Distributed Object Computing (EDOC) and Role Activity Diagram (RAD) models is suggested. We also introduce model driven approach (MDA) of Object Modelling Group (OMG) in order to describe an abstract level for common communication among business partners.

An immune inspired co-evolutionary affinity network for prefetching of distributed object

In distributed object computing (DOC) containers, cache strategy as a passive approach improves the performance by caching the recently accessed objects. By the advent of large-scale enterprise applications of DOC, caching methods fail to keep pace with the increasing importance of performance and the increasing scale of DOC system. Prefetching is an effective approach to improve the performance. It generates and stores pages or objects in caches in advance, by predicting the requests. In the current DOC container, prefetching strategy is not supported and seldom studied in the literature. The immune system with faster secondary response and its affinity network inspire applying the immune mechanisms to build holistic model of DOC for performance improvement. In this study, a co-evolutionary affinity network (CEA-Net) is proposed for prefetching distributed objects. In CEA-Net, objects are antibodies and computation tasks are antigens. Invocation relations among object classes are modeled by the immune network of antibody genotypes. Multiple affinity measures among antibody, antigen, genotypes of antibody and antigen, genotype set and antibody population are defined to model the complex relations among distributed objects. Especially in the antibody population, immune principles including clonal proliferation, immune memory, immune toleration and elimination are designed to add evolutionary features to the antibody population. Based on CEA-Net, the prefetching architecture for DOC is built including 5 main procedures, Network Abstractor, Access Recorder, Object Factory, Cache Engine and Prefetch Engine. Finally, the experimental study shows the promising access performance and the evolutionary features of CEA-Net. CEA-Net is instructive for the future design of high performance DOC containers, such as WebSphere Application Server and BEA WebLogic Application Server.

An antibody network inspired evolutionary framework for distributed object computing

In order to meet the increasing scale and users requirements for the distributed object computing (DOC) systems, their infrastructures are highly desirable to be redesigned. Based on the principles of immune system and the evolution mechanisms learned from an antibody network model, a novel evolutionary framework for DOC (E-DOC) is proposed. The antibody network model as well as the evolution process including clonal proliferation, immune elimination, and immune memory is studied. Then, E-DOC framework based on the antibody network is proposed, whose simulation platform is designed and implemented. On the platform, the evolutionary features are studied by: (1) diversity and stability of antibodies and genotypes, (2) detection and elimination of antigens, (3) effect of immune memory, and (4) tendency of eliminated and stimulated antigens. The experiment results show that the proposed framework can achieve the evolution ability and the promising performance, which are critical to DOC systems. E-DOC is extendable for the future design of distributed object middleware, such as WebSphere Application Server and BEA WebLogic Application Server.

Analytical study of object components for distributed and ubiquitous computing environment

The Distributed object computing is a paradigm that allows objects to be distributed across a heterogeneous network, and allows each of the components to interoperate as a unified whole. A new gene...

Embedded Component Technology for Complex Control Systems

The question of finding the best technology for software-based controller deployment is still open. One of the main problems is that computing infrastructures for controllers are composed by heterogeneous hardware and software platforms scattered over a set of heterogeneous networkig infrastructures. The standardised object-oriented efforts done around the the OMG specifications try to overcome some of the difficulties raised by this heterogeneity. Inside the Distributed Object Computing (DOC) landscape, CORBA is a well known framework for the construction of modularised, object oriented, distributed applications. The CORBA object model, however, is not enough when confronting the problems related to deplyment, configuration and evolutionary maintenance of systems. This paper describes the ECF component technology specifically built for the construction of component-based, distributed embedded systems.

Enterprise Modelling using Unified Framework supporting Distributed Object Computing

This paper provides a support for the analysis phase in the life cycle of the enterprise distributed computing systems. The major goal of our work is to provide a small but powerful set of enterprise modeling concepts. We will be extending the concept of Enterprise Modeling using EDOC inter-agent system using OPEN Framework.

A model-driven development framework for enterprise Web services

The growing scale and complexity of the enterprise computing systems under distributed and heterogeneous environments present new challenges to system development, integration, and maintenance. In this paper, we present a model driven Web service development framework to combat these challenges. The framework capitalizes on the unified modeling language (UML) profile for enterprise distributed object computing (EDOC), MDA (model-driven architecture) and Web services. Within the framework, firstly, a general PIM (platform independent models) is created using the EDOC CCA structural specification and CCA choreography specification which defines the general functions of a system. Secondly, the general PIM is broken down into sub-PIMs according to functional decomposition, each of which can provide service independently and will be implemented in a Web service. Thirdly, all of the PIMs are transformed to Web service interface models for publication and invoking. Afterward, transform each PIM to a BPEL specified Web service orchestration model. Finally, supported by model transform techniques, the sub EDOC PIMs are implemented into Web services on specific platforms. Automatic model transformation is the key to this framework, therefore, the transformation from EDOC CCA models to WSDL specified Web service interface models and the transformation from EDOC CCA models to BPEL specified Web service orchestration models are deeply discussed, and the detailed transformation rules are proposed. A case study is also provided to demonstrate the effectiveness of these rules and the merits of this framework.

A modeiing approach for designing a value chain of virtual enterprise

As the advent of digital economy changes business environment dramatically, virtual enterprise (VE), in general the interactions among business partners in a value chain, has become a key factor to survive under the competitive business environment. VE reveals that more complex and dynamic business processes should be considered as assembled service components in order to integrate the collaborative business processes. Therefore, a formal standard schema for describing and managing the business processes is required. In this paper, we propose a consistent modeling approach that combines enterprise modeling and simulation modeling to design a value chain of a VE. This methodology will provide designers with insight into the business processes of a VE and help identify and resolve unpredictable bottlenecks on the execution of virtual business processes. This paper also illustrates an implemented modeling tool which is based on the generalized model suggested by the working group of the international conference on enterprise integration and modeling technology (ICEIMT) and notations by the object management group (OMG)’s unified modeling language (UML) profile for enterprise distributed object computing (EDOC).

2005 EDOC: meeting the challenges of enterprise computing

An increasing demand for interoperable applications exists, sparking the real-time exchange of data across borders, applications, and IT platforms. To perform these tasks, enterprise computing now encompasses a new class of groundbreaking technologies such as Web services and service-oriented architecture (SOA); business process integration and management; and middleware support, like that for utility, grid, peer-to-peer, and autonomic computing. Enterprise computing also influences the processes for business modeling, consulting, and service delivery; it affects the design, development, and deployment of software architecture, as well as the monitoring and management of such architecture. As enterprises demand increasing levels of networked information and services to carry out business processes, IT professionals need conferences like EDOC to discuss emerging technologies and issues in enterprise computing. For these reasons, what started out as the Enterprise Distributed Object Computing (EDOC) conference has come to encompass much more than just distributed objects. So this event now used the name International EDOC Enterprise Computing Conference, to recognize this broader scope yet also retain the initial conference's name recognition.

THE USE OF CORBA IN PROCESS CONTROL

Present-day control systems in a process plant are composed by a heterogeneous collection of hardware and software entities scattered over a set of heterogeneous platforms. This HW/SW heterogeneity is a source of extreme complexity in the control system regarded as a whole. To implement the new complex control systems Distributed Object Computing (DOC) seems the adequate technology. In the global DOC landscape, CORBA is a well known framework for the construction of modularised, object oriented, distributed applications. The use of CORBA-based control systems (CCS) has been investigated recently with promising results demonstrating the use of CORBA for Process Control Systems.

Towards Real-Time Fault-Tolerant CORBA Middleware

An increasing number of applications are being developed using Distributed Object Computing (DOC) middleware, such as CORBA. Many of these applications require the underlying middleware, operating systems, and networks to provide dependable end-to-end Quality of Service (QoS) support to enhance their efficiency, predictability, scalability, and reliability. The Object Management Group (OMG), which standardizes CORBA, has addressed many of these application requirements individually in the Real-Time CORBA (RT-CORBA) and Fault-Tolerant CORBA (FT-CORBA) specifications. Though the implementations of RT-CORBA are suitable for mission-critical commercial or military distributed Real-Time and Embedded (DRE) systems, the usage of FT-CORBA with RT-CORBA implementations are not yet suitable for systems that have stringent simultaneous dependability and predictability requirements. This paper provides three contributions to the study and evaluation of dependable CORBA middleware for performance-sensitive DRE systems. First, we provide an overview of FT-CORBA and illustrate the sources of unpredictability associated with conventional FT-CORBA implementations. Second, we discuss the QoS requirements of an important class of mission-critical DRE systems to show how these requirements are not well served by FT-CORBA today. Finally, we empirically evaluate new dependability strategies for FT-CORBA that can help make the use of DOC middleware for mission-critical DRE systems a reality.

Application research and implementation of the CORBA-Based Web distributed network management system

The distributed management has become an important tendency of development for the NMS (Network Management System) with the development of Internet. Based on the analysis of CORBA (Conmon Object Request Broker Architecture) technique, we mainly discuss about the applicability of the approach by which CORBA combined with Java has been applied to the system model and Web architecture: and address the applied frame and the interface definitions that are the, key technologies for implementing the Distributed Object Computing (DOC). In addition, we also conduct the research on its advantages and disadvantages and further expected improvements.

On Load Balancing Approaches for Distributed Object Computing Systems

Distributed object computing systems are widely envisioned to be the desired distributed software development paradigm in the near future due to the higher modularity and the capability of handling machine and operating system heterogeneity. Indeed, enabled by the tremendous advancements in processor and networking technologies, complex operations such as object serialization and data marshalling become very efficient, and thus, distributed object systems are being built for many different applications. As the system scales up (e.g., with larger number of server and client objects, and more machines), a judicious load balancing system is required to efficiently distribute the workload (e.g., the queries, messages/objects passing) among different servers in the system. Several such load balancing schemes are proposed recently in the literature. However, while the rationales and mechanisms employed are dramatically different, the relative strengths and weaknesses of these approaches are unknown, making it difficult for a practitioner to choose an appropriate approach for the problem at hand. In this paper, we describe in detail three representative approaches, which are all practicable, and present a quantitative comparison using a real experimental distributed object computing platform. Among these three approaches, namely, JavaSpaces based, request redirection based, and fuzzy decision based, we find that the fuzzy decision-based algorithm outperforms the other two considerably under a wide range of different practical scenarios.

Towards a Balanced Specification Language for Distributed Object Computing Patterns

Despite the benefits offered by distributed object computing, there are a lot of key challenges that need to be addressed when developing distributed applications. Design patterns help alleviate those challenges by shifting the developer's focus towards high-level design concerns rather than platform-specific details. However, the inherent ambiguity of existing textual and graphical descriptions of design patterns does not help users understand and apply them easily. Formal specification of design patterns is not meant to replace existing means of pattern descriptions, but to complement them in order to achieve accuracy and allow rigorous reasoning about them. The main problem of existing formal specification languages for design patterns is lack of completeness. This is mainly because they tend to focus on specifying either the structural or behavioural aspect of design patterns, but not both of them. We propose a simple yet balanced pattern specification language (BPSL) that is intended to achieve equilibrium by specifying both aspects of design patterns. The language combines two subset of logic, one from first-order logic and one from temporal logic of actions.

Towards a Balanced Specification Language for Distributed Object Computing Patterns

Despite the benefits offered by distributed object computing, there are a lot of key challenges that need to be addressed when developing distributed applications. Design patterns help alleviate those challenges by shifting the developer's focus towards high-level design concerns rather than platform-specific details. However, the inherent ambiguity of existing textual and graphical descriptions of design patterns does not help users understand and apply them easily. Formal specification of design patterns is not meant to replace existing means of pattern descriptions, but to complement them in order to achieve accuracy and allow rigorous reasoning about them. The main problem of existing formal specification languages for design patterns is lack of completeness. This is mainly because they tend to focus on specifying either the structural or behavioural aspect of design patterns, but not both of them. We propose a simple yet balanced pattern specification language (BPSL) that is intended to achieve equilibrium by specifying both aspects of design patterns. The language combines two subset of logic, one from first-order logic and one from temporal logic of actions.

Workflow-enabled distributed component-based information architecture for digital medical imaging enterprises.

Few information systems today offer a flexible means to define and manage the automated part of radiology processes, which provide clinical imaging services for the entire healthcare organization. Even fewer of them provide a coherent architecture that can easily cope with heterogeneity and inevitable local adaptation of applications and can integrate clinical and administrative information to aid better clinical, operational, and business decisions. We describe an innovative enterprise architecture of image information management systems to fill the needs. Such a system is based on the interplay of production workflow management, distributed object computing, Java and Web techniques, and in-depth domain knowledge in radiology operations. Our design adapts the approach of "4+1" architectural view. In this new architecture, PACS and RIS become one while the user interaction can be automated by customized workflow process. Clinical service applications are implemented as active components. They can be reasonably substituted by applications of local adaptations and can be multiplied for fault tolerance and load balancing. Furthermore, the workflow-enabled digital radiology system would provide powerful query and statistical functions for managing resources and improving productivity. This paper will potentially lead to a new direction of image information management. We illustrate the innovative design with examples taken from an implemented system.

CORBA-Based Distributed Geographic Information Systems for Transportation for Emergency Medical Services

With the advancement of intelligent transportation systems, current and future emergency medical services systems are and will be characterized by real-time response, specialization, and decentralization. To provide a real-time response of medical services, several components are essential, such as dispatching, routing, emergency facilities, and patient’s medical history. A common object request broker architecture (CORBA)–based geographic information system for a transportation framework is proposed for the dispatching and assignment of medical vehicles for emergency services via wireless communication. The framework combines distributed object computing, geographic information systems for transportation, and transportation models in a single system, which provides flexibility and interoperability among existing medical service systems. The framework uses the concept of distributed systems and capabilities of CORBA to design objects and dynamically update medical facilities’ information to relay up-to-date information to ambulances. A real roadway network is used in the numerical experiments to illustrate dynamic aspects of the proposed system.