Architectural support for quality of service for CORBA objects
01 Jan 1997-Theory and Practice of Object Systems (John Wiley & Sons, Inc.)-Vol. 3, Iss: 1, pp 55-73
TL;DR: The architecture, Quality of Service for CORBA Objects (QuO), is described, which is developed to overcome limitations and integrate their solution by providing QoS abstractions to CORBA objects.
Abstract: CORBA is a commercial standard for distributed object computing which shows great promise in the development of distributed programs. Its interface description language (IDL) enables objects to be developed independently of the underlying programming language, operating system, or computer architecture on which they will execute. While this is sufficient in many environments, programs deployed in a wide-area distributed system encounter conditions which are much more hostile and varying than those operating in a single address space or within a single local area network. In this paper we discuss four major problems we have observed in our developing and deploying wide-area distributed object applications and middleware. First, most programs are developed ignoring the variable wide area conditions. Second, when application programmers do try to handle these conditions, they have great difficulty because these harsh conditions are different from those of the local objects they are used to dealing with. Third, IDL hides information about the tradeoffs any implementation of an object must make. Fourth, there is presently no way to systematically reuse current technology components which deal with these conditions, so code sharing becomes impractical. In this paper we also describe our architecture, Quality of Service for CORBA Objects (QuO), which we have developed to overcome these limitations and integrate their solution by providing QoS abstractions to CORBA objects. First, it makes these conditions first class entities and integrates knowledge of them over time, space, and source. Second, it reduces their variance by masking. Third, it exposes key design decisions of an object's implementation and how it will be used. Fourth, it supports reuse of various architectural components and automatically generates others. © 1997 John Wiley & Sons, Inc.
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Book•
14 Sep 2000
TL;DR: The patterns catalogued in this second volume of Pattern-Oriented Software Architectures (POSA) form the basis of a pattern language that addresses issues associated with concurrency and networking.
Abstract: From the Publisher:
Designing application and middleware software to run in concurrent and networked environments is a significant challenge to software developers The patterns catalogued in this second volume of Pattern-Oriented Software Architectures (POSA) form the basis of a pattern language that addresses issues associated with concurrency and networking
The book presents 17 interrelated patterns ranging from idioms through architectural designs They cover core elements of building concurrent and network systems: service access and configuration, event handling, synchronization,
and concurrency All patterns present extensive examples and known uses in multiple programming languages, including C++, C, and Java
The book can be used to tackle specific software development problems or read from cover to cover to provide a fundamental understanding of the best practices for constructing concurrent and networked applications and middleware
About the Authors
This book has been written by the award winning team responsible for the first POSA volume "A System of Patterns", joined in this volume by Douglas C Schmidt from University of California, Irvine (UCI), USA
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1,012 citations
01 Jan 2002
TL;DR: This paper presents a predictive QoS model that makes it possible to compute the quality of service for workflows automatically based on atomic task QoS attributes, and presents the implementation of the model for the METEOR workflow system.
Abstract: Workflow management systems (WfMSs) have been used to support various types of business processes for more than a decade now. In workflows for e-commerce and Web service applications, suppliers and customers define a binding agreement or contract between the two parties, specifying Quality of Service (QoS) items such as products or services to be delivered, deadlines, quality of products, and cost of services. The management of QoS metrics directly impacts the success of organizations participating in e-commerce. Therefore, when services or products are created or managed using workflows, the underlying workflow system must accept the specifications and be able to estimate, monitor, and control the QoS rendered to customers. In this paper, we present a predictive QoS model that makes it possible to compute the quality of service for workflows automatically based on atomic task QoS attributes. To this end, we present a model that specifies QoS and describe an algorithm and a simulation system in order to compute, analyze and monitor workflow QoS metrics.
980 citations
Cites background from "Architectural support for quality o..."
...…is associated with a fidelity function F(t), which represents the local normalized fidelity: F(t) = |f1(F(t).ai)| wi1 + | f2(F(t).aj)| wi2 + | f3(F(t).ak)| wi3 + … + | fn(F(t).al)| win The formula weights the fidelity attributes, which can be transformed to more appropriate values using a…...
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TL;DR: In this article, the authors present a predictive QoS model that makes it possible to compute the quality of service (QoS) for workflows automatically based on atomic task QoS attributes.
807 citations
Book•
23 Nov 2007TL;DR: This work defines the set-theoretic operators on an instance of a neutrosophic set, and calls it an Interval Neutrosophics Set (INS), and introduces a new logic system based on interval neutrosophile sets and proposed data model based on the extension of fuzzy data model and paraconsistent data model.
Abstract: A neutrosophic set is a part of neutrosophy that studies the origin, nature, and scope of neutralities, as well as their interactions with different ideational spectra. The neutrosophic set is a powerful general formal framework that has been recently proposed. However, the neutrosophic set needs to be specified from a technical point of view. Here, we define the set-theoretic operators on an instance of a neutrosophic set, and call it an Interval Neutrosophic Set (INS). We prove various properties of INS, which are connected to operations and relations over INS. We also introduce a new logic system based on interval neutrosophic sets.
We study the interval neutrosophic propositional calculus and interval neutrosophic predicate calculus. We also create a neutrosophic logic inference system based on interval neutrosophic logic. Under the framework of the interval neutrosophic set, we propose a data model based on the special case of the interval neutrosophic sets called Neutrosophic Data Model. This data model is the extension of fuzzy data model and paraconsistent data model. We generalize the set-theoretic operators and relation-theoretic operators of fuzzy relations and paraconsistent relations to neutrosophic relations. We propose the generalized SQL query constructs and tuple-relational calculus for Neutrosophic Data Model.
We also design an architecture of Semantic Web Services agent based on the interval neutrosophic logic and do the simulation study.
643 citations
TL;DR: The paper describes the design of TAO, which is the high-performance, real-time CORBA 2.0-compliant implementation that runs on a range of OS platforms with real- time features including VxWorks, Chorus, Solaris 2.x, and Windows NT, and presents TAO'sreal-time scheduling service that can provide QoS guarantees for deterministic real-Time CORBA applications.
588 citations
Cites background from "Architectural support for quality o..."
...For instance, admission control can be used for global resource managers [39, 40] that map applications onto computational, storage, and network resources in a large-scale distributed system, such as a ship-board computing environment....
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...Determining how to map the insights and mechanisms produced by QoS work at the network and OS layers onto an OO programming model is a key challenge when adding QoS support to ORB middleware [15, 40]....
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...The QuO project at BBN [40] has defined a model for communicating changes in QoS characteristics between applications, middleware, and the underlying endsystems and network....
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References
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PARC1
TL;DR: The resource reservation protocol (RSVP) as discussed by the authors is a receiver-oriented simplex protocol that provides receiver-initiated reservations to accommodate heterogeneity among receivers as well as dynamic membership changes.
Abstract: A resource reservation protocol (RSVP), a flexible and scalable receiver-oriented simplex protocol, is described. RSVP provides receiver-initiated reservations to accommodate heterogeneity among receivers as well as dynamic membership changes; separates the filters from the reservation, thus allowing channel changing behavior; supports a dynamic and robust multipoint-to-multipoint communication model by taking a soft-state approach in maintaining resource reservations; and decouples the reservation and routing functions. A simple network configuration with five hosts connected by seven point-to-point links and three switches is presented to illustrate how RSVP works. Related work and unresolved issues are discussed. >
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PARC1
TL;DR: A new approach to programming language design is presented, which resolves fundamental tensions between elegance and efficiency, and a metaobject protocol is presented that gives users the ability to incrementally modify the language's behavior and implementation.
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30 Jul 1991
TL;DR: In this article, the authors present a new approach to programming language design, which resolves fundamental tensions between elegance and efficiency, called metaobject protocols, which are interfaces to the lanaguage that give users the ability to incrementally modify the language's behavior and implementation, as well as to write programs within the language.
Abstract: From the Publisher:
This book presents a new approach to programming language design, which resolves fundamental tensions between elegance and efficiency. Metaobject protocols are interfaces to the lanaguage that gives users the ability to incrementally modify the language's behavior and implementation, as well as the ability to write programs within the language. In this way, a metaobject protocol allows users to adjust the lanaguage to better suit their needs.
1,100 citations
TL;DR: A resource reservation protocol (RSVP), a flexible and scalable receiver-oriented simplex protocol, that provides receiver-initiated reservations to accommodate heterogeneity among receivers as well as dynamic membership changes and supports a dynamic and robust multipoint-to-multipoint communication model.
Abstract: A resource reservation protocol (RSVP), a flexible and scalable receiver-oriented simplex protocol, is described. RSVP provides receiver-initiated reservations to accommodate heterogeneity among receivers as well as dynamic membership changes; separates the filters from the reservation, thus allowing channel changing behavior; supports a dynamic and robust multipoint-to-multipoint communication model by taking a soft-state approach in maintaining resource reservations; and decouples the reservation and routing functions. A simple network configuration with five hosts connected by seven point-to-point links and three switches is presented to illustrate how RSVP works. Related work and unresolved issues are discussed. >
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08 Jul 1996
TL;DR: In this paper, the authors look at a number of distributed systems that have attempted to paper over the distinction between local and remote objects, and show that such systems fail to support basic requirements of robustness and reliability.
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440 citations