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Article
Publication date: 1 February 1994

TRANSITION MATRIX COMPUTATION FOR A PERIODICALLY TIME‐VARYING SYSTEM

A.O.M. SALEH and M.A. LAUGHTON

A quantitative method for the estimation of the discrete transition matrix is developed for the periodic time‐varying system of state differential equations governing…

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Abstract

A quantitative method for the estimation of the discrete transition matrix is developed for the periodic time‐varying system of state differential equations governing electrical synchronous machine behaviour. The approach allows the eigensystem of this transition matrix to be calculated to an arbitrary accuracy without significant added computational burden by using modal structural properties of the state‐space equations.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 13 no. 2
Type: Research Article
DOI: https://doi.org/10.1108/eb010126
ISSN: 0332-1649

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Book part
Publication date: 3 December 2018

Bibliography

Jan Keane

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National Identity and Education in Early Twentieth Century Australia
Type: Book
DOI: https://doi.org/10.1108/978-1-78769-245-920181009
ISBN: 978-1-78769-246-6

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Article
Publication date: 1 January 1990

PERFORMANCE EVALUATION OF THE SECOND‐ORDER LOADFLOW CONTINGENCY METHODS

A.O. Ekwue

The superiority of the fast‐decoupled loadflow [FDLF] method is attributable to the underlying decoupling assumptions which, however, may not be valid for all modes of…

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The superiority of the fast‐decoupled loadflow [FDLF] method is attributable to the underlying decoupling assumptions which, however, may not be valid for all modes of system operation. For example, during a restoration period following an emergency or in circumstances of unusual plant outages the assumptions of near nominal voltages and small phase angle differences may not be valid. Also for equivalencing methods, if large values of shunt admittance are contributed by the equivalent external networks, or if tap‐changing transformers are included, the FDLF method has shortcomings.

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COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 9 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/eb010323
ISSN: 0332-1649

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Article
Publication date: 29 July 2020

Current-source 1-Ph inverter design for aircraft applications

Eralp Sener and Gurhan Ertasgin

This paper aims to present an inverter with a current-source input for 400 Hz avionic systems to have a system which removes DC-link capacitors and presents a high efficiency.

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Abstract

Purpose

This paper aims to present an inverter with a current-source input for 400 Hz avionic systems to have a system which removes DC-link capacitors and presents a high efficiency.

Design/methodology/approach

A battery-powered DC link inductor generates a constant-current source. A single high-frequency switch is used to provide a sinusoidally modulated current before the inverter. The output of the switch is “unfolded” by a thyristor-based H-bridge inverter to generate an AC output current. The system uses a CL low-pass filter to obtain a 400 Hz pure sine wave by removing pulse width modulation components.

Findings

Simulations and Typhoon HIL real-time experiments were performed with closed-loop control to validate the proposed inverter concept while meeting the critical standards of MIL-STD-704F.

Originality/value

This current source inverter topology is suitable for avionic systems that require 400 Hz output frequency. The topology uses small DC-link inductor and eliminates bulky capacitor which determines the inverter lifetime.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 8
Type: Research Article
DOI: https://doi.org/10.1108/AEAT-10-2019-0194
ISSN: 1748-8842

Keywords

  • Aircraft
  • Power electronics
  • Avionics
  • Current source inverter

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Article
Publication date: 1 January 1989

EFFICIENCY OF HIERARCHIC AGGLOMERATIVE CLUSTERING USING THE ICL DISTRIBUTED ARRAY PROCESSOR

EDIE M. RASMUSSEN and PETER WILLETT

The implementation of hierarchic agglomerative methods of cluster anlaysis for large datasets is very demanding of computational resources when implemented on conventional…

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The implementation of hierarchic agglomerative methods of cluster anlaysis for large datasets is very demanding of computational resources when implemented on conventional computers. The ICL Distributed Array Processor (DAP) allows many of the scanning and matching operations required in clustering to be carried out in parallel. Experiments are described using the single linkage and Ward's hierarchical agglomerative clustering methods on both real and simulated datasets. Clustering runs on the DAP are compared with the most efficient algorithms currently available implemented on an IBM 3083 BX. The DAP is found to be 2.9–7.9 times as fast as the IBM, the exact degree of speed‐up depending on the size of the dataset, the clustering method, and the serial clustering algorithm that is used. An analysis of the cycle times of the two machines is presented which suggests that further, very substantial speed‐ups could be obtained from array processors of this type if they were to be based on more powerful processing elements.

Details

Journal of Documentation, vol. 45 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/eb026836
ISSN: 0022-0418

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Article
Publication date: 1 March 1911

The Library World Volume 13 Issue 9

THE earliest catalogue of Cambridge University documents was compiled by Mr. William Rysley, in 1420. Most of the documents enumerated in this list are still extant. An…

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THE earliest catalogue of Cambridge University documents was compiled by Mr. William Rysley, in 1420. Most of the documents enumerated in this list are still extant. An interesting List of the Documents in the University Registry, from the year 1266 to the year 1544, was communicated to the Cambridge Antiquarian Society by the Rev. H. R. Luard, B.D., then University Registrar, on March 6th, 1876. From this, it appears that “The earliest document which the University possesses is so late as the year 1266. The earliest in the Record office is dated 16th July, 13 Hen. III., i.e. 1229. This is a permission to scholars of the University of Paris to come to England, and remain for purposes of study.”

Details

New Library World, vol. 13 no. 9
Type: Research Article
DOI: https://doi.org/10.1108/eb008944
ISSN: 0307-4803

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Article
Publication date: 1 February 1991

MULTIOBJECTIVE PLANNING OF THE OPTIMAL VOLTAGE PROFILE IN ELECTRIC POWER DISTRIBUTION SYSTEMS

Ignacio J. RAMIREZ‐ROSADO and R.N. ADAMS

Multiobjective planning models for electric power distribution system planning can include multiple aspects such as community amenity values, geographical conditions of…

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Multiobjective planning models for electric power distribution system planning can include multiple aspects such as community amenity values, geographical conditions of the study area, reliability evaluations (mainly in terms of service continuity), or the optimal voltage profile in the network, as well as the basic planning aspects: power demand requirements, power capacity limits and the minimization of the total system expansion costs. On the other hand, classical single objective planning models have usually considered only the basic aspects. This paper describes a multiobjective model to find the optimal voltage profile and to look for the least cost system expansion simultaneously. Furthermore, two multiobjective techniques for the application of the model to distribution system expansion problems are outlined. The computer results have shown that multiobjective models are able to find solutions which include multiple planning objectives simultaneously, and that these solutions are advantageous compared with the ones from classical single objective models.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 10 no. 2
Type: Research Article
DOI: https://doi.org/10.1108/eb010085
ISSN: 0332-1649

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Article
Publication date: 5 January 2015

Electrical engineering reference resources: a survey from LibGuides

Nestor L Osorio

– The purpose of this survey is to find a significant sample of reference resources for electrical engineering as they are presented in subject-specific LibGuides.

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Abstract

Purpose

The purpose of this survey is to find a significant sample of reference resources for electrical engineering as they are presented in subject-specific LibGuides.

Design/methodology/approach

The survey is based on a detailed observation and collection of sources designated as Reference Resources in LibGuides, titles found were compiled and organized.

Findings

The results are substantial; they offered a body of specialized resources, which includes e-book collections, dictionaries, handbooks, encyclopedias and other resources that are important to electrical engineering students and researchers.

Research limitations/implications

A considerable amount of resources were found; nevertheless, they represent the resources found in a randomly selected sample of LibGuides; therefore, the result is limited to the group of libraries selected.

Practical implications

The results of this survey are valuable to subject librarians interested in comparing resources with a pool of libraries and to discover titles that can be of interest to their collections.

Originality/value

The work is original, as this is the first paper publishing the results of a survey of electrical engineering guides.

Details

Collection Building, vol. 34 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/CB-07-2014-0035
ISSN: 0160-4953

Keywords

  • Electrical engineering
  • LibGuides
  • E-book collections
  • Reference resources

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Article
Publication date: 25 January 2013

Different academics' characteristics, different perceptions on quality assessment?

Sónia Cardoso, Maria João Rosa and Cristina S. Santos

The purpose of this paper is to explore Portuguese academics' perceptions on higher education quality assessment objectives and purposes, in general, and on the recently…

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Abstract

Purpose

The purpose of this paper is to explore Portuguese academics' perceptions on higher education quality assessment objectives and purposes, in general, and on the recently implemented system for higher education quality assessment and accreditation, in particular. It aims to discuss the differences of those perceptions dependent on some academics' characteristics, such as: gender, disciplinary affiliation, type of higher education institution and experience in quality assurance activities.

Design/methodology/approach

An online questionnaire with Likert‐type answer scales was distributed to the Portuguese academic population (n=36,215). In total, 962 answers were collected from academics belonging to the public higher education system. Data were treated resorting to descriptive statistics, hypothesis tests and analysis of variance.

Findings

Portuguese academics tend to support the majority of goals and purposes quality assessment may have, as well as the main features of the newly designed quality assessment and accreditation system. Nevertheless they tend to support more quality assessment mechanisms privileging improvement over control. This support is slightly more evident among female academics, academics from public polytechnic institutions, from medical and health sciences and with former experience in quality assurance activities.

Originality/value

The study adds to the discussion on academics' perceptions on quality assurance, highlighting the influence played at this level by some of their characteristics. It is especially relevant for those working either in higher education institutions or governmental agencies, since it may contribute to the design of quality assurance systems academics are more likely to support.

Details

Quality Assurance in Education, vol. 21 no. 1
Type: Research Article
DOI: https://doi.org/10.1108/09684881311293089
ISSN: 0968-4883

Keywords

  • Higher education
  • Quality assessment
  • Academic staff
  • Portugal
  • Quality assurance

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Article
Publication date: 1 June 1937

The Library World Volume 39 Issue 11

SCARBOROUGH, as a conference town, will be remembered for a long time, because for a few days it provided perfect weather, after one of the dreariest Springs of which…

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SCARBOROUGH, as a conference town, will be remembered for a long time, because for a few days it provided perfect weather, after one of the dreariest Springs of which there is record. This was not unbroken, because for two days there was a good deal of rain, but, on the whole, the impression that remains is good. Weather has an important bearing on these meetings, for when weather breaks at them, tempers may also break—as they did at the Annual Business Meeting, which in some ways was the most unseemly we remember. The Mayor and Mayoress made capital hosts; the Chairman of the Libraries Committee, Councillor T. Laughton, was a young and worthy host in himself as well; and Mr. Smettem and his staff had given much work to arrangements for the comfort of the guests which were entirely successful. Added to this, as we anticipated would be the case, the Scarborough Public Library proved to be unusually attractive, and if the tribute that it was the best organized in England (which Mr. E. A. Savage paid to it at the Annual Dinner) was in a somewhat high key, few desired to find fault with it.

Details

New Library World, vol. 39 no. 11
Type: Research Article
DOI: https://doi.org/10.1108/eb009199
ISSN: 0307-4803

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