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Article
Publication date: 1 September 2000

Tsao‐Tsung Ma, Kwok Lun Lo and Mehmet Tumay

This paper proposes an ANN based adaptive damping control scheme for the unified power flow controller (UPFC) to damp the low frequency electromechanical power…

Abstract

This paper proposes an ANN based adaptive damping control scheme for the unified power flow controller (UPFC) to damp the low frequency electromechanical power oscillations. In this paper a novel damping control strategy based on the time‐domain analysis of system transient energy function (TEF) is proposed and implemented by using well tuned conventional PI controllers to obtain the preliminary training data for the design of the proposed controllers. The multi‐layered feed forward neural network with error back‐propagation training algorithm is employed in this study. Models of UPFC and ANN controllers suitable for incorporating with the transient simulation programs are derived and tested on a revised IEEE nine‐bus test system. Comprehensive simulation results demonstrate the great potential of using UPFC in damping control and the excellent performance of the proposed control scheme.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 19 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2002

K.L. Lo, W.P. Luan, M. Given, M. Bradley and H.B. Wan

Automatic contingency selection aims to quickly predict the impact of a set of next contingencies on an electric power system without actually performing a full ac load…

Abstract

Automatic contingency selection aims to quickly predict the impact of a set of next contingencies on an electric power system without actually performing a full ac load flow. Artificial neural network methods have been employed to overcome the masking effects or slow execution associated with existing methods. However, the large number of input features for the ANN limits its applications to large power systems. In this paper, a novel feature selection method, named the Weak Nodes method, based on a heuristic approach is proposed for an ANN‐based automatic contingency selection for electric power system, especially for the voltage ranking problem. Pre‐contingency state variables of weak nodes in the power system are adopted as input features for the ANN. The method is tested on the 77 busbar NGC derived network by Counter‐propagation Method and it is proved that it reduces the input features for ANN dramatically without losing ranking accuracy.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 21 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Book part
Publication date: 13 September 2018

Chin How (Norman) Goh, Michael D. Short, Nanthi S. Bolan and Christopher P. Saint

Biosolids, the residual solids from wastewater treatment operations and once considered a waste product by the industry, are now becoming increasingly recognised as a…

Abstract

Biosolids, the residual solids from wastewater treatment operations and once considered a waste product by the industry, are now becoming increasingly recognised as a multifunctional resource with growing opportunities for marketable use. This shift in attitude towards biosolids management is spurred on by increasing volatility in energy, fertilizer and commodity markets as well as moves by the global community towards mitigating global warming and the effects of climate change. This chapter will provide an overview of current global biosolids practices (paired with a number of Australian examples) as well as discuss potential future uses of biosolids. Additionally, present and future risks and opportunities of biosolids use are highlighted, including potential policy implications.

Details

Unmaking Waste in Production and Consumption: Towards the Circular Economy
Type: Book
ISBN: 978-1-78714-620-4

Keywords

Article
Publication date: 16 January 2017

Louise Stoll and Marco Kools

Schools today have to prepare students for life and work in a fast-changing world, for jobs and for using technologies some of which have not yet been created. But the…

1923

Abstract

Purpose

Schools today have to prepare students for life and work in a fast-changing world, for jobs and for using technologies some of which have not yet been created. But the schools and school systems are not keeping up and all too often, teachers are not developing the practices and skills required to meet today’s learners’ diverse needs. Changes indicate a greater imperative but also some cautions. This review is part of the attempt to work towards a common understanding of schools as learning organisations (SLOs) today which is both solidly founded in the literature and recognisable currently by researchers, practitioners and policy makers in many countries. But this is not just a theoretical exercise. If it is to be truly relevant and have the necessary impact, the concept also needs to support those who are interested in transforming or further developing their school(s) into learning organisations (LO) at this point in time. In this paper, the authors first summarise different perspectives on the concept of the LO as used more generally across disciplines. Next, the authors describe the methodology for exploring the SLO and discuss definitional issues, before presenting a summary of the integrated model with accompanying rationale, Finally the authors discuss plans to bring the model to life, with associated issues for researchers, educators and policy makers. The paper aims to discuss these issues.

Design/methodology/approach

The search for this literature in the English language was carried out through: focussed searches of nine electronic databases – ERIC, SAGE, Google Scholar, Taylor & Francis, Emerald, JSTOR, SpringerLink, Google, Science Direct – using the search terms “SLO” and “learning school”; and contacts with leading experts in this area of work which led to identification of additional literature. The first approach led to selection of 25 most frequently found publications on the SLO and/or learning school. Through the second approach, the authors used an additional seven publications to further enrich the analysis. The interdisciplinary review was extended to include investigation of related organisational change, learning, school improvement and effectiveness literatures.

Findings

The starting hypothesis is that the seven action-oriented dimensions of the model together add up to a sustainable LO; that is, successfully realising all seven dimensions is greater than the sum of the parts. But, it is not clear how the individual dimensions relate to each other, and whether some are more important than others. Elements within dimensions are also likely to vary across country contexts. Over the next few years the authors will explore and amend the model, together with practitioners, policy makers and researchers from around the globe.

Practical implications

Despite differences in interpretation, common features emerge. First, there is general agreement that the SLO is a necessity for dealing with the rapidly changing external environment by any school organisation, regardless of context. This is exemplified by application of the concept in many countries including, for example, Australia, Canada, England and Wales, Iran, Israel, Korea, Malaysia, South-Africa and the USA. Second, the SLO is defined as “organic” and closely connected to its external environment. Third, the SLO literature strongly emphasises the importance of individual, group and organisational learning with inquiry, problem solving and experimentation as key drivers of change and innovation. Last, the literature highlights the importance of beliefs, values and norms of employees for continuous and collaborative learning, and processes, strategies and structures to create the conditions for such learning, experimentation and innovation to flourish. The review led to the design of a new action-oriented model. In its current form, the model is intended to offer a stimulus and provide practical guidance on how schools might support and use learning at all levels to improve and transform themselves into a LO and ultimately enhance outcomes. The language is deliberately action-oriented, and elements highlight both what a school aspires to and the processes it goes through in its journey of developing itself as a LO.

Originality/value

While the concept of a school LO is not new, at a time of constant and complex change, this multi-disciplinary international literature review has given it a new lease of life: drawing on previous studies, but connecting these to a wider relevant knowledge base and the current context. It offers a way forward while arguing that deeper understanding is needed on how schools can develop as LOs. It is now informing the OECD’s work on SLOs with policy makers and practitioners in different countries and the findings are being used to help assess impact at a range of levels.

Details

Journal of Professional Capital and Community, vol. 2 no. 1
Type: Research Article
ISSN: 2056-9548

Keywords

Article
Publication date: 10 August 2020

Efrosini Siougle and Sophia Dimelis

This is a longitudinal study exploring the effect of ISO 9000 certification on firm's financial performance in the pre-crisis period and the 2008 financial crisis period.

Abstract

Purpose

This is a longitudinal study exploring the effect of ISO 9000 certification on firm's financial performance in the pre-crisis period and the 2008 financial crisis period.

Design/methodology/approach

The empirical analysis is based on a 22-year dataset with balance sheet data from 136 Greek listed firms covering the period 1992–2013. A matching technique is applied to properly estimate potential differences in the impact of ISO 9000 on firm's financial performance between the groups of certified and matched non-certified (control) firms in the entire period but, most importantly, in pre-crisis vs crisis periods, using the difference-in-differences econometric approach.

Findings

The findings indicate that certified firms exhibit significantly higher financial performance relative to the matched non-certified group in both the pre-crisis and crisis periods, which tends to persist for several years post-certification. The financial crisis has a negative and statistically significant effect on firm performance in both the certified and matched non-certified groups, which nevertheless did not differ significantly between them. Controlling for sectoral and technological differences did not harm the higher performance of certified firms relative to the matched control peers. The results remain in the same direction when the authors test the ISO 9000 effect in the sub-group of certified firms that obtained the certification at the firm-level.

Originality/value

The study is original in its sample design and hypothesis testing. The matched sample created from a sufficiently long and continuous time dataset enabled the authors to properly estimate firm performance differences of ISO 9000 between pre-crisis and crisis periods. Of additional value is the testing of sectoral/technological differences and the distinction between firm-level and plant-level certification.

Details

International Journal of Quality & Reliability Management, vol. 38 no. 3
Type: Research Article
ISSN: 0265-671X

Keywords

Article
Publication date: 1 December 1999

K.L. Lo, W.P. Luan, M. Given, J.F. Macqueen, A.O. Ekwue and A.M. Chebbo

Voltage ranking attempts to rank busbar voltage deviations from their normally accepted security margins based on a set of performance indices (PI), without performing a…

Abstract

Voltage ranking attempts to rank busbar voltage deviations from their normally accepted security margins based on a set of performance indices (PI), without performing a full load flow. Existing methods suffer from either masking effects or long computation time. In this paper, an artificial neural network method is proposed for voltage ranking. Counterpropagation network (CPN) has been employed to overcome the problems listed above. A variety of input features are used with the aim of lowering the dimension of the proposed ANN to make it applicable for large power systems. The method is tested on two example systems, a five‐bus system and a 71‐bus system with very encouraging results.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 18 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 March 2005

Mahmoud Oukati Sadegh and K.L. Lo

This paper seeks to propose a systematic method to design multi fuzzy FACTS based stabilizers in a multi‐machine power system.

1073

Abstract

Purpose

This paper seeks to propose a systematic method to design multi fuzzy FACTS based stabilizers in a multi‐machine power system.

Design/methodology/approach

Conventional FACTS based stabilizers are decentralized controllers that adopt local measurements and operate in closed loop. To improve overall system dynamic performance, a coordinating application of FACTS based stabilizer is essential. Although, numerous researches have indicated the effectiveness and superiority of fuzzy logic controllers in comparison with the conventional linear controllers in power system application but researchers have not adequately investigated coordination of multi fuzzy controllers in multi‐machine power systems to provide optimal performance. Genetic algorithm is used to determine optimum values of controllers' parameters.

Findings

The search space of the optimisation procedure is decreased to a smaller one, design and computation time can be reduced significantly and the design process becomes more systematic.

Originality/value

A systematic method is introduced to coordinate multi fuzzy FACTS based stabilizers in multi‐machine power systems.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2004

K.L. Lo and Haji Izham Haji Zainal Abidin

This paper describes voltage collapse in power system networks and how it could lead to a collapse of the whole system. Discusses the effect of machine learning and…

1193

Abstract

This paper describes voltage collapse in power system networks and how it could lead to a collapse of the whole system. Discusses the effect of machine learning and artificial intelligence, leading to new methods. Spotlight, the fuzzy decision tree (FDT) method and its application to voltage collapse assessments. Concludes that FDT can identify and group data sets, giving a new understanding of its application in voltage collapse analysis.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 June 2002

Y.J. Lin and K.L. Lo

This paper develops a proportional plus derivative (PD) control scheme for a thyristor controlled series compensator (TCSC) to reinforce power system damping performance…

Abstract

This paper develops a proportional plus derivative (PD) control scheme for a thyristor controlled series compensator (TCSC) to reinforce power system damping performance. This PD control scheme is aided by the use of genetic algorithms (GAs). The effectiveness of the proposed method is demonstrated through computer simulation using a multi‐machine power system associated with a single TCSC. Results show that the proposed PD controller can achieve good damping performance.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 21 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Book part
Publication date: 28 May 2019

Rinnelle Lee-Piggott

Often new principals approach their first appointments with a high expectation to make their mark by introducing changes that would lead to school improvement. However…

Abstract

Often new principals approach their first appointments with a high expectation to make their mark by introducing changes that would lead to school improvement. However, these expectations may be void of thoughts of how an inherited school culture may weigh on their emotions and upset their notions about principalship on a daily basis. Emerging from a multiple case study research design, in which a critical incident technique was the main source of data on new principals’ emotional experiences, the findings show that the new principals experienced predominantly negative emotions and wounding, often linked to pre-formed expectations of school members. Also, influenced by a need to protect their leadership authority, they selected which emotions to disclose versus which to suppress. These findings as drawn from a broader study conducted in Trinidad and Tobago imply a need for training and continuing professional development that would support aspirant and practising principals’ emotion regulation.

Details

Emotion Management and Feelings in Teaching and Educational Leadership
Type: Book
ISBN: 978-1-78756-011-6

Keywords

1 – 10 of over 9000