7,565 research outputs found
Object-oriented Tools for Distributed Computing
Distributed computing systems are proliferating, owing to the availability of powerful, affordable microcomputers and inexpensive communication networks. A critical problem in developing such systems is getting application programs to interact with one another across a computer network. Remote interprogram connectivity is particularly challenging across heterogeneous environments, where applications run on different kinds of computers and operating systems. NetWorks! (trademark) is an innovative software product that provides an object-oriented messaging solution to these problems. This paper describes the design and functionality of NetWorks! and illustrates how it is being used to build complex distributed applications for NASA and in the commercial sector
Improving the Scalability of DPWS-Based Networked Infrastructures
The Devices Profile for Web Services (DPWS) specification enables seamless
discovery, configuration, and interoperability of networked devices in various
settings, ranging from home automation and multimedia to manufacturing
equipment and data centers. Unfortunately, the sheer simplicity of event
notification mechanisms that makes it fit for resource-constrained devices,
makes it hard to scale to large infrastructures with more stringent
dependability requirements, ironically, where self-configuration would be most
useful. In this report, we address this challenge with a proposal to integrate
gossip-based dissemination in DPWS, thus maintaining compatibility with
original assumptions of the specification, and avoiding a centralized
configuration server or custom black-box middleware components. In detail, we
show how our approach provides an evolutionary and non-intrusive solution to
the scalability limitations of DPWS and experimentally evaluate it with an
implementation based on the the Web Services for Devices (WS4D) Java Multi
Edition DPWS Stack (JMEDS).Comment: 28 pages, Technical Repor
Evaluating XMPP Communication in IEC 61499-based Distributed Energy Applications
The IEC 61499 reference model provides an international standard developed
specifically for supporting the creation of distributed event-based automation
systems. Functionality is abstracted into function blocks which can be coded
graphically as well as via a text-based method. As one of the design goals was
the ability to support distributed control applications, communication plays a
central role in the IEC 61499 specification. In order to enable the deployment
of functionality to distributed platforms, these platforms need to exchange
data in a variety of protocols. IEC 61499 realizes the support of these
protocols via "Service Interface Function Blocks" (SIFBs). In the context of
smart grids and energy applications, IEC 61499 could play an important role, as
these applications require coordinating several distributed control logics.
Yet, the support of grid-related protocols is a pre-condition for a wide-spread
utilization of IEC 61499. The eXtensible Messaging and Presence Protocol (XMPP)
on the other hand is a well-established protocol for messaging, which has
recently been adopted for smart grid communication. Thus, SIFBs for XMPP
facilitate distributed control applications, which use XMPP for exchanging all
control relevant data, being realized with the help of IEC 61499. This paper
introduces the idea of integrating XMPP into SIFBs, demonstrates the
prototypical implementation in an open source IEC 61499 platform and provides
an evaluation of the feasibility of the result.Comment: 2016 IEEE 21st International Conference on Emerging Technologies and
Factory Automation (ETFA
Planning and Design Soa Architecture Blueprint
Service Oriented Architecture (SOA) is a framework for integrating business processes and supporting IT infrastructure as secure, standardized components-services-that can be reused and combined to address changing business priorities. Services are the building blocks of SOA and new applications can be constructed through consuming these services and orchestrating services within a business process. In SOA, services map to the business functions that are identified during business process analysis. Upon a successful implementation of SOA, the enterprise gain benefit by reducing development time, utilizing flexible and responsive application structure, and following dynamic connectivity of application logics between business partners. This paper presents SOA reference architecture blueprint as the building blocks of SOA which is services, service components and flows that together support enterprise business processes and the business goals
A conformance test framework for the DeviceNet fieldbus
The DeviceNet fieldbus technology is introduced and discussed. DeviceNet is an open standard fieldbus which uses the proven Controller Area Network technology. As an open standard fieldbus, the device conformance is extremely important to ensure smooth operation. The error management in DeviceNet protocol is highlighted and an error injection technique is devised to test the implementation under test for the correct error-recovery conformance. The designed Error Frame Generator prototype allows the error management and recovery of DeviceNet implementations to be conformance tested. The Error Frame Generator can also be used in other Controller Area Network based protocols.
In addition, an automated Conformance Test Engine framework has been defined for realising the conformance testing of DeviceNet implementations. Automated conformance test is used to achieve consistent and reliable test results, apart from the benefits in time and personnel savings. This involves the investigations and feasibility studies in adapting the ISO 9646 conformance test standards for use in DeviceNet fieldbus.
The Unique Input/Output sequences method is used for the generation of DeviceNet conformance tests. The Unique Input/Output method does not require a fully specified protocol specification and gives shorter test sequences, since only specific state information is needed. As conformance testing addresses only the protocol verification, it is foreseen that formal method validation of the DeviceNet protocol must be performed at some stage to validate the DeviceNet specification
Service-Oriented Architecture for Space Exploration Robotic Rover Systems
Currently, industrial sectors are transforming their business processes into
e-services and component-based architectures to build flexible, robust, and
scalable systems, and reduce integration-related maintenance and development
costs. Robotics is yet another promising and fast-growing industry that deals
with the creation of machines that operate in an autonomous fashion and serve
for various applications including space exploration, weaponry, laboratory
research, and manufacturing. It is in space exploration that the most common
type of robots is the planetary rover which moves across the surface of a
planet and conducts a thorough geological study of the celestial surface. This
type of rover system is still ad-hoc in that it incorporates its software into
its core hardware making the whole system cohesive, tightly-coupled, more
susceptible to shortcomings, less flexible, hard to be scaled and maintained,
and impossible to be adapted to other purposes. This paper proposes a
service-oriented architecture for space exploration robotic rover systems made
out of loosely-coupled and distributed web services. The proposed architecture
consists of three elementary tiers: the client tier that corresponds to the
actual rover; the server tier that corresponds to the web services; and the
middleware tier that corresponds to an Enterprise Service Bus which promotes
interoperability between the interconnected entities. The niche of this
architecture is that rover's software components are decoupled and isolated
from the rover's body and possibly deployed at a distant location. A
service-oriented architecture promotes integrate-ability, scalability,
reusability, maintainability, and interoperability for client-to-server
communication.Comment: LACSC - Lebanese Association for Computational Sciences,
http://www.lacsc.org/; International Journal of Science & Emerging
Technologies (IJSET), Vol. 3, No. 2, February 201
TechNews digests: Jan - Nov 2005
TechNews is a technology, news and analysis service aimed at anyone in the education sector keen to stay informed about technology developments, trends and issues. TechNews focuses on emerging technologies and other technology news. TechNews service : digests september 2004 till May 2010 Analysis pieces and News combined publish every 2 to 3 month
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