Dynamic policy-based management in open distributed environments

This chapter introduces a programming environment for SCI clusters that takes advantage of both parallel and distributed programming paradigms. It aims at helping programmers to design high performance applications based on the assembling of generic software components. This environment is based on CORBA (Common Object Request Broker Architecture), with our own extensions to support parallelism across several cluster nodes within a distributed system. Our contribution concerns extensions to support a new kind of object, which we call a parallel CORBA object (or parallel object), as well as the integration of message-passing paradigms, mainly MPI, within a parallel object. These extensions exploit as much as possible the functionality offered by CORBA and require few modifications to an available CORBA implementation. This paper reports on these extensions and the description of a runtime system, called Cobra, which provides resource allocation services for the execution of parallel objects.

To develop a conventional CORBA(Common Object Request Broker Architecture)-based distributed object system, first the system’s requirements must be analyzed in requirements analysis step and system’s overall interface and details must be specified and built using IDL(Interface Definition Language) in design step. However, there are not too many models available that can be used as a benchmark in specifying the requirements and details of the CDO(CORBA-based distributed object) system. Conversion to IDL from requirements analysis step or preliminary design stage is a difficult task and an effective method for verification of IDL is not currently available. In the light of unique features of distributed object system, IDL errors that occur in the beginning of software development become the main causes of errors for the system as a whole. This paper suggests SACC (Software Architecture-based CORBA Component) model as a solution to the problems mentioned above m specifying details and verifying CDO system. SACC model uses SCI (SACC Converted IDL) algorithms to be converted to IDL. SACC model utilizes software architecture approach. SACC modeling method uses CTL (Computational Tree Logic) to verify CORBA system that is specified by SACC model. In conclusion, SACC modeling method is proven effective in specifying details and verifying the CDO system. Furthermore, it helps programmers to effectively convert to IDL, which is highly reliable.

In the search for competitive advantage, network management systems are becoming increasingly important to public network operators. In an attempt to reduce the cost of management systems, the telecommunications community have, for many years, been working on the standardisation of interfaces between systems to encourage a multi-vendor environment. As the computing and telecommunications domains converge, there is now a possibility to use distributed object technology to increase the cost-effectiveness of management systems. This paper discusses experiences of using the Common Object Request Broker Architecture (CORBA) as a basis for a public telecommunications network management system platform.Keyword CodesC.2.4D.1.5D.1.1KeywordsDistributed SystemsObject-oriented ProgrammingApplicative (Functional) Programming

A mobile service robot is a complex distributed system integrating various technologies and having large heterogeneity. In order to facilitate component development and system integration of the mobile service robots, a middleware-based simulation and control framework for system integration and application development, as well as the robotic functional component (RFC) framework with a simplified structure and an efficient transmission scheme, is proposed for mobile service robot systems. Designed to implement a distributed modular mechanism for a mobile service robot, the middleware-based framework for simulation and control is comprised of four layers: low-level abstraction layer, communication layer, high-level abstraction layer, and application layer. Common Object Request Broker Architecture (CORBA) and Robot Technology Middleware (RTM) are employed as middleware for the development of RFCs and for system integration. Communication between the components and the graphical programming tool is done by the communication layer (CORBA ORB). The conducted experiments validated the proposed framework in terms of ideal performance of reusability, interoperability, and extensibility, as well as indicated that the proposed RFC framework is simplified and easy enough to perform well in data transmission, which will reduce the costs and the threshold of robot development.

The integration of heterogeneous networks and systems is one of the more urgent requirements expressed by networks and computer users. ISO and ITU-T normalisation bodies have contributed in a significant manner to the definition of a global management framework called TMN (Telecommunication Management Network). TMN is an agreed framework that permitted to a number of public and private network operators to build their management system. However, these existing systems are confronted to the heterogeneity of emerging technologies. In fact, new equipment is built with specific management interfaces, which are not conforming, to the TMN one. The heterogeneity considered in this paper is the one that emerges from the OMG (Object Management Group) CORBA (Common Object Request Broker Architecture). In fact, a lot of CORBA based systems are emerging in the field of management. In this context, telecommunication operators are willing in the short term to use their existing management systems to control them in a uniform way. The aim of this paper is to propose solutions to these problems through the use of Q Adapter that permits to integrate CORBA based equipment into the global management framework based on TMN.KeywordsManagementCORBAOSIAdaptationObjectProtocolService

Traditionally, most definitions seeking to characterize middleware suggest that it is the software that facilitates remote database access and systems transactions. More recently, the term has come to be associated-somewhat limitingly-with distributed platforms such as the Open Software Foundation's Distributed Computing Environment (DCE) and the Object Management Group's Common Object Request Broker Architecture (CORBA). And some have loosely applied it to systems as diverse as workflow support environments and even to the Web itself. We believe the essential role of middleware is to manage the complexity and heterogeneity of distributed infrastructures and thereby provide a simpler programming environment for distributed-application developers. It is therefore most useful to define middleware as any software layer that is placed above the distributed system's infrastructure-the network OS and APIs-and below the application layer.

The common security policies of access control and resource management are based upon a central managing authority, called the system administration, that is ultimately responsible for the management of a usage policy. This management is usually done with some combination of mandatory access control and discretionary access control methods, where each user is granted (or denied) privileges and resources depending on the usage policies enforced at that particular system. System administration includes the management of system resources, user accounts, and user privileges. This security policy is typified by an operating system such as UNIX, and it introduces several dificulties when working in a distributed computing environment. This paper addresses distributed resource management and access control. It proposes a new version of the “Distributed Compartment Model” (DChf), first developed by Greenwald in his 1994 doctoral dissertation. DCM consists of two major components: Handles, a method for role based access control, and Distributed Compartments, a method allowing users to manage resources within a distributed system across administrative domain boundaries. This new version of DCM discussed in this paper is a refinement of the original formal security policy model. This paper concentrates on the history and background of the problems motivating the creation of DCM, describes the informal security policy, proposes some ezample scenan’os as to how DCM could be used, and concludes with a discussion of the results of this research.

Exploiting distributed object technology to achieve networked inventory management

Describes the initial design work of the New Zealand Distributed Information Systems (NZDIS) research project, which seeks to develop an architecture for building distributed information systems from existing information resources, based on software agent and distributed object technologies. An agent-based architecture is used, with messages exchanged via the FIPA (Foundation for Intelligent Physical Agents) agent communication language (ACL). Novel features of this system include the use of standards from the object-oriented programming community, such as the Common Object Request Broker Architecture (CORBA) as a communications infrastructure, the Unified Modeling Language (UML), which is used as an ontology representation language, the Object Data Management Group's Object Query Language (OQL), which is used for queries, and the Object Management Group's Meta Object Facility (MOF), which is used as the basis for an ontology repository agent. 'Stringified' object references may be returned as the content of ACL messages, allowing query results to be made available via a variety of CORBA interfaces.

The paper describes our SoftDock system, which is a distributed model management system to support collaborative software development. SoftDock leverages the team development, tool interoperability, and model continuity across development lifecycle. It supports Unified Modeling Language (UML) to specify software models, and maintains the model information with UML eXchange Format (UXF), which is a XML-based model interchange format. UXF-encoded model descriptions are shared and managed through the Document Object Model (DOM) interface implemented on top of CORBA (Common Object Request Broker Architecture) middleware. The paper describes the SoftDock architecture, system organization, and design considerations in managing UXF descriptions in the distributed environment.

Policy-based management can guide the behavior of a network or distributed system through high-level declarative directives that are dynamically introduced, checked for consistency, refined, and evaluated, resulting typically in a series of low-level actions. We actually view policies as a means of extending the functionality of management systems dynamically, in conjunction with preexisting hard-wired management logic. We first discuss the policy management aspects of architecture for managing quality of service in IP DiffServ networks as presented by Trimintzios et al. (see IEEE Commun. Mag., Special Issue in IP Operations and Management, vol.39, no.5, p.80-88, 2001), and focus on the functionality of the dimensioning and resource management aspects. We then present an analysis of the policies that can influence the dimensioning behavior as well as the inconsistencies that may be caused by the introduction of such policies. Finally, we describe the design and implementation of the generic policy consumer component and present the current implementation status.

The Telecommunications Management Network (TMN) has been developed as the framework to support administrations in managing telecommunications networks. It suggests the use of OSI Systems Management (OSI-SM) as the technology for management information exchanges. Distributed object technologies, such as the Common Object Request Broker architecture (CORBA), address the use of software application program interfaces (APIs) in addition to interoperable protocols. Their use in TMN has been the subject of intensive research in previous years, with most approaches focusing on interoperability aspects with OSI-SM. We examine the issues behind using distributed object technologies in TMN via a native fashion, with network elements supporting distributed objects directly, e.g., a CORBA to the switch approach. The proposed solution tries to maintain the full OSI-SM expressive power in a way that other solutions have not attempted before. Performance and scalability issues are considered, while the approach has been validated through implementation.

Component-based software development would allow application software to be largely constructed rather than programmed. This approach would dramatically improve the productivity of software development. Although there are many reusable software packages available, the integration of the chosen parts remains a very difficult problem because there are many barriers of integration, including programming languages, operating systems, communication mechanism, interface, etc. In this paper, an approach to developing real-time application software based on a distributed component architecture and cross-platform and cross-language integration of these software components is presented. The Common Object Request Broker Architecture (CORBA) is used in the implementation. The distributed components will satisfy easy retrieval and integration over a heterogeneous distributed system environment. A component replication mechanism is used for providing fault-tolerance. Using object adapters with a real-time request monitor and scheduler that are transparently generated by a distributed component integration tool, real-time and fault-tolerance features can be easily incorporated in the application software.

<p>For decades the primary focus of language policy research has been activities by states and their agencies, while language policy activities in workplaces have attracted little attention. Addressing this gap, explicit and implicit dimensions of language policies are investigated in financial institutions operating in the globalised context of international banking in multilingual Luxembourg. Three complementary theoretical frameworks are used to extend language policy research to include not just explicit aspects of language policy (language policy statements), but also implicit aspects (the language practices and beliefs of a community). Spolsky's (2004) theory is used to identify and analyse three components of language policy (management, practices and beliefs); Language Management Theory (LMT) (Jernudd and Neustupny, 1987) is used to explore one specific component of language policy (management), and Shohamy's (2006) framework is used to explore the complex interaction between management, practices and beliefs. The data base for the study comprised two phases: the first phase involved interviews with managers in ten Luxembourg banks regarding language policy, followed in the second phase by questionnaires and focus-group discussions with employees from three case study banks regarding language use and beliefs. This empirical data suggests that even in banks where English has been formalised as the working language, multilingual mechanisms (recruitment and language courses) contribute to employees' practices effectively creating, a top-down multilingual implicit (de facto) policy. The data from international banks in Luxembourg suggests that a flexible approach to language management is useful in workplaces where communication is complex, multi-faceted and dynamic. The bottom-up perspective indicates that employees at international banks use English as a lingua franca (ELF) alongside other languages, negotiating language choice across speech communities and linguistic repertoires, for transactional and relational purposes. These multilingual employees highly value English as the most common language in banks for including and involving all, highlighting its vital role in banks. Because the data provides a strong argument for the consideration of both top down and bottom up perspectives, the results have theoretical significance for our understanding of language policy. Overall, this thesis provides insights into the complex nature of language policy in multilingual workplaces, including the importance of both top-down and bottom-up pressures on language practices, the crucial role of ELF and the relevance of attitudes towards ELF and other languages at local and global levels of management.</p>

Resolve Security Policies Conflicts Through Semantics Matching Alignment