5,166 research outputs found
On-line transformer condition monitoring through diagnostics and anomaly detection
This paper describes the end-to-end components of an on-line system for diagnostics and anomaly detection. The system provides condition monitoring capabilities for two in- service transmission transformers in the UK. These transformers are nearing the end of their design life, and it is hoped that intensive monitoring will enable them to stay in service for longer. The paper discusses the requirements on a system for interpreting data from the sensors installed on site, as well as describing the operation of specific diagnostic and anomaly detection techniques employed. The system is deployed on a substation computer, collecting and interpreting site data on-line
Practical applications of multi-agent systems in electric power systems
The transformation of energy networks from passive to active systems requires the embedding of intelligence within the network. One suitable approach to integrating distributed intelligent systems is multi-agent systems technology, where components of functionality run as autonomous agents capable of interaction through messaging. This provides loose coupling between components that can benefit the complex systems envisioned for the smart grid. This paper reviews the key milestones of demonstrated agent systems in the power industry and considers which aspects of agent design must still be addressed for widespread application of agent technology to occur
An Integrated Methodology for Creating Composed Web/Grid Services
This thesis presents an approach to design, specify, validate, verify, implement, and evaluate composed web/grid services. Web and grid services can be composed to create new services
with complex behaviours. The BPEL (Business Process Execution Language) standard was created to enable the orchestration of web services, but there have also been investigation of
its use for grid services. BPEL specifies the implementation of service composition but has no formal semantics; implementations are in practice checked by testing. Formal methods are
used in general to define an abstract model of system behaviour that allows simulation and reasoning about properties. The approach can detect and reduce potentially costly errors at
design time.
CRESS (Communication Representation Employing Systematic Specification) is a domainindependent,
graphical, abstract notation, and integrated toolset for developing composite web service. The original version of CRESS had automated support for formal specification in
LOTOS (Language Of Temporal Ordering Specification), executing formal validation with MUSTARD (Multiple-Use Scenario Testing and Refusal Description), and implementing in
BPEL4WS as the early version of BPEL standard. This thesis work has extended CRESS and its integrated tools to design, specify, validate, verify, implement, and evaluate composed web/grid
services. The work has extended the CRESS notation to support a wider range of service compositions, and has applied it to grid services as a new domain. The thesis presents two new
tools, CLOVE (CRESS Language-Oriented Verification Environment) and MINT (MUSTARD Interpreter), to respectively support formal verification and implementation testing. New work
has also extended CRESS to automate implementation of composed services using the more recent BPEL standard WS-BPEL 2.0
Diagnosis of Errors in Stalled Inter-Organizational Workflow Processes
Fault-tolerant inter-organizational workflow processes help participant organizations efficiently complete their business activities and operations without extended delays. The stalling of inter-organizational workflow processes is a common hurdle that causes organizations immense losses and operational difficulties. The complexity of software requirements, incapability of workflow systems to properly handle exceptions, and inadequate process modeling are the leading causes of errors in the workflow processes.
The dissertation effort is essentially about diagnosing errors in stalled inter-organizational workflow processes. The goals and objectives of this dissertation were achieved by designing a fault-tolerant software architecture of workflow system’s components/modules (i.e., workflow process designer, workflow engine, workflow monitoring, workflow administrative panel, service integration, workflow client) relevant to exception handling and troubleshooting. The complexity and improper implementation of software requirements were handled by building a framework of guiding principles and the best practices for modeling and designing inter-organizational workflow processes.
Theoretical and empirical/experimental research methodologies were used to find the root causes of errors in stalled workflow processes. Error detection and diagnosis are critical steps that can be further used to design a strategy to resolve the stalled processes. Diagnosis of errors in stalled workflow processes was in scope, but the resolution of stalled workflow process was out of the scope in this dissertation. The software architecture facilitated automatic and semi-automatic diagnostics of errors in stalled workflow processes from real-time and historical perspectives. The empirical/experimental study was justified by creating state-of-the-art inter-organizational workflow processes using an API-based workflow system, a low code workflow automation platform, a supported high-level programming language, and a storage system. The empirical/experimental measurements and dissertation goals were explained by collecting, analyzing, and interpreting the workflow data. The methodology was evaluated based on its ability to diagnose errors successfully (i.e., identifying the root cause) in stalled processes caused by web service failures in the inter-organizational workflow processes.
Fourteen datasets were created to analyze, verify, and validate hypotheses and the software architecture. Amongst fourteen datasets, seven datasets were created for end-to-end IOWF process scenarios, including IOWF web service consumption, and seven datasets were for IOWF web service alone. The results of data analysis strongly supported and validated the software architecture and hypotheses. The guiding principles and the best practices of workflow process modeling and designing conclude opportunities to prevent processes from getting stalled. The outcome of the dissertation, i.e., diagnosis of errors in stalled inter-organization processes, can be utilized to resolve these stalled processes
Continuous maintenance and the future – Foundations and technological challenges
High value and long life products require continuous maintenance throughout their life cycle to achieve required performance with optimum through-life cost. This paper presents foundations and technologies required to offer the maintenance service. Component and system level degradation science, assessment and modelling along with life cycle ‘big data’ analytics are the two most important knowledge and skill base required for the continuous maintenance. Advanced computing and visualisation technologies will improve efficiency of the maintenance and reduce through-life cost of the product. Future of continuous maintenance within the Industry 4.0 context also identifies the role of IoT, standards and cyber security
NASA SBIR abstracts of 1991 phase 1 projects
The objectives of 301 projects placed under contract by the Small Business Innovation Research (SBIR) program of the National Aeronautics and Space Administration (NASA) are described. These projects were selected competitively from among proposals submitted to NASA in response to the 1991 SBIR Program Solicitation. The basic document consists of edited, non-proprietary abstracts of the winning proposals submitted by small businesses. The abstracts are presented under the 15 technical topics within which Phase 1 proposals were solicited. Each project was assigned a sequential identifying number from 001 to 301, in order of its appearance in the body of the report. Appendixes to provide additional information about the SBIR program and permit cross-reference of the 1991 Phase 1 projects by company name, location by state, principal investigator, NASA Field Center responsible for management of each project, and NASA contract number are included
A fault fuzzy-ontology for large scale fault-tolerant wireless sensor networks
International audienceFault tolerance is a key research area for many of applications such as those based on sensor network technologies. In a large scale wireless sensor network (WSN), it becomes important to find new methods for fault-tolerance that can meet new application requirements like Internet of things, urbane intelligence and observation systems. The challenge is beyond the limit of a single wireless sensor network and concerns multiple widely interconnected sub networks. The domain of fault grows considerably because of this new configuration. In this context, the paper proposes a fault fuzzy-ontology (FFO) for large scale WSNs to be used within a Web service architecture for diagnosis and testing
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