Search results

1 – 10 of 17
To view the access options for this content please click here
Article

Akhtar Rasool, Esref Emre Ozsoy, Fiaz Ahmad, Asif Sabanoviç and Sanjeevikumar Padmanaban

This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions.

Abstract

Purpose

This paper aims to propose a novel grid current control strategy for grid-connected voltage source converters (VSCs) under unbalanced grid voltage conditions.

Design/methodology/approach

A grid voltage dynamic model is represented in symmetrical positive and negative sequence reference frames. A proportional controller structure with a first-order low-pass filter disturbance observer (DOB) is designed for power control in unbalanced voltage conditions. This controller is capable of meeting the positive sequence power requirements, and it also eliminates negative sequence power components which cause double-frequency oscillations on power. The symmetrical components are calculated by using the second-order generalized integrator-based observer, which accurately estimates the symmetrical components.

Findings

Proportional current controllers are sufficient in this study in a wide range of operating conditions, as DOB accurately estimates and feed-forwards nonlinear terms which may be deteriorated by physical and operating conditions. This is the first reported scheme which estimates the VSC disturbances in terms of symmetrical component decomposition and the DOB concept.

Originality/value

The proposed method does not require any grid parameter to be known, as it estimates nonlinear terms with a first-order low-pass filter DOB. The proposed control system is implemented on a dSPACE ds1103 digital controller by using a three-phase, three-wire VSC.

Details

World Journal of Engineering, vol. 14 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article

Fiaz Ahmad, Akhtar Rasool, Esref Emre Ozsoy, Asif Sabanoviç and Meltem Elitas

This paper aims to propose a robust cascaded controller based on proportional-integral (PI) and continuous sliding mode control.

Abstract

Purpose

This paper aims to propose a robust cascaded controller based on proportional-integral (PI) and continuous sliding mode control.

Design/methodology/approach

Cascaded control structure is an attractive control scheme for DC-DC power converters. It has a two-loop structure where the outer loop contains PI controller and the inner loop uses sliding mode control (SMC). This structure thus combines the merits of both the control schemes. However, there are some issues that have prohibited its adoption in industry, the discontinuous nature of SMC which leads to variable switching frequency operation and is hard to realize practically. This paper attempts to overcome this issue by changing the discontinuous functionality of SMC to continuous by utilizing the concept of equivalent control.

Findings

The robustness of the controller designed is verified by considering various cases, namely, ideal case with no uncertainties, sudden variation of input supply voltage, load resistance, reference voltage, circuit-parameters and for noise disturbance. The controller effectiveness is validated by simulating the DC-DC boost and Cuk converters in SimPowerSystems toolbox of MATLAB/Simulink. It is shown that the performance of the proposed controller is satisfactory, and both reference output voltage and inductor current are tracked with little or no sensitivity to disturbances.

Originality/value

The results for various scenarios are interesting and show that the controller works quite satisfactorily for all the simulated uncertainties.

Details

World Journal of Engineering, vol. 14 no. 5
Type: Research Article
ISSN: 1708-5284

Keywords

To view the access options for this content please click here
Article

Fiaz Ahmad, Kabir Muhammad Abdul Rashid, Akhtar Rasool, Esref Emre Ozsoy, Asif Sabanoviç and Meltem Elitas

To propose an improved algorithm for the state estimation of distribution networks based on the unscented Kalman filter (IUKF). The performance comparison of unscented…

Abstract

Purpose

To propose an improved algorithm for the state estimation of distribution networks based on the unscented Kalman filter (IUKF). The performance comparison of unscented Kalman filter (UKF) and newly developed algorithm, termed Improved unscented Kalman Filter (IUKF) for IEEE-30, 33 and 69-bus radial distribution networks for load variations and bad data for two measurement noise scenarios, i.e. 30 and 50 per cent are shown.

Design/methodology/approach

State estimation (SE) plays an instrumental role in realizing smart grid features like distribution automation (DA), enhanced distribution generation (DG) penetration and demand response (DR). Implementation of DA requires robust, accurate and computationally efficient dynamic SE techniques that can capture the fast changing dynamics of distribution systems more effectively. In this paper, the UKF is improved by changing the way the state covariance matrix is calculated, to enhance its robustness and accuracy under noisy measurement conditions. UKF and proposed IUKF are compared under the cummulative effect of load variations and bad data based on various statistical metrics such as Maximum Absolute Deviation (MAD), Maximum Absolute Per cent Error (MAPE), Root Mean Square Error (RMSE) and Overall Performance Index (J) for three radial distribution networks. All the simulations are performed in MATLAB 2014b environment running on an hp core i5 laptop with 4GB memory and 2.6 GHz processor.

Findings

An Improved Unscented Kalman Filter Algorithm (IUKF) is developed for distribution network state estimation. The developed IUKF is used to predict network states (voltage magnitude and angle at all buses) and measurements (source voltage magnitude, line power flows and bus injections) in the presence of load variations and bad data. The statistical performance of the coventional UKF and the proposed IUKF is carried out for a variety of simulation scenarios for IEEE-30, 33 and 69 bus radial distribution systems. The IUKF demonstrated superiority in terms of: RMSE; MAD; MAPE; and overall performance index J for two measurement noise scenarios (30 and 50 per cent). Moreover, it is shown that for a measurement noise of 50 per cent and above, UKF fails while IUKF performs.

Originality/value

UKF shows degraded performance under high measurement noise and fails in some cases. The proposed IUKF is shown to outperform the UKF in all the simulated scenarios. Moreover, this work is novel and has justified improvement in the robustness of the conventional UKF algorithm.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article

Fiaz Ahmad, Akhtar Rasool, Esref Emre Ozsoy, Asif Sabanoviç and Meltem Elitas

The purpose of this paper is to propose successive-over-relaxation (SOR) based recursive Bayesian approach (RBA) for the configuration identification of a Power System…

Abstract

Purpose

The purpose of this paper is to propose successive-over-relaxation (SOR) based recursive Bayesian approach (RBA) for the configuration identification of a Power System. Moreover, to present a comparison between the proposed method and existing RBA approaches regarding convergence speed and robustness.

Design/methodology/approach

Swift power network configuration identification is important for adopting the smart grid features like power system automation. In this work, a new SOR-based numerical approach is adopted to increase the convergence speed of the existing RBA algorithm and at the same time maintaining robustness against noise. Existing RBA and SOR-RBA are tested on IEEE 6 bus, IEEE 14 bus networks and 48 bus Danish Medium Voltage distribution network in the MATLAB R2014b environment and a comparative analysis is presented.

Findings

The comparison of existing RBA and proposed SOR-RBA is performed, which reveals that the latter has good convergence speed compared to the former RBA algorithms. Moreover, it is robust against bad data and noise.

Originality value

Existing RBA techniques have slow convergence and are also prone to measurement noise. Their convergence speed is effected by noisy measurements. In this paper, an attempt has been made to enhance convergence speed of the new identification algorithm while keeping its numerical stability and robustness during noisy measurement conditions. This work is novel and has drastic improvement in the convergence speed and robustness of the former RBA algorithms.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

To view the access options for this content please click here
Article

Fiaz Ahmad, Arshad Munir, Zafar‐uz‐Zaman and Naveed Zafar Ali

The purpose of this paper is to establish some acceptable trends in the contamination of roadside vegetation and to define a safety limit regarding the effects of metal…

Abstract

Purpose

The purpose of this paper is to establish some acceptable trends in the contamination of roadside vegetation and to define a safety limit regarding the effects of metal contamination arising from various toxic metals deposited on leaves of the plants and in the bulk of the fruits.

Design/methodology/approach

Distribution of essential and non‐essential elements on the surface of leaves and in bulk of fruits of specific areas of Multan (Pakistan) was estimated and correlated with World Health Organization (WHO) standards. The metal concentrations are expressed as X ± SD for triplicate sub samples with the SD of ± 1.0‐1.5 per cent. The maximum metal levels in bulk of various fruits were calculated for FE, followed by Cu, Zn and Co.

Findings

In samples from roadside leaves Fe (823 mg/kg) was found to be the dominant metal, whereas the observed threshold level was found for Co (17.25 mg/kg). The non‐essential elements in various fruits, the Cr was found to be the dominate (16 mg/kg) on mean basis as compared with other metals in fruits. The increasing order of non‐essential metals on the surface of roadside leaves was Li < Ni < Sr < Pb < Cr. The results revealed that metal concentration decreases with increase in distance from roadside (10, 30 and 50 m) with negative correlation coefficient.

Originality/value

This paper shows that the metals concentration in case of all fruit samples fall within the permissible safe limit, whereas the metal concentrations on the surface of roadside leaves were found to surpass the safe limits laid down by the WHO. It is consequently suggested that edible portions of vegetation and fruits near highways should be consumed cautiously.

Details

Nutrition & Food Science, vol. 39 no. 2
Type: Research Article
ISSN: 0034-6659

Keywords

To view the access options for this content please click here
Article

Abdul Aziz Khan Niazi, Tehmina Fiaz Qazi, Irfan Ali and Rashid Ahmad

In current vista of corporate governance (CG), whistleblowing (WB) has become critical for practitioners, researchers and other stakeholders. This study aims to identify…

Abstract

Purpose

In current vista of corporate governance (CG), whistleblowing (WB) has become critical for practitioners, researchers and other stakeholders. This study aims to identify, prioritize and analyze the interrelationships of determinants of effective WB on the basis of opinion of a medium-sized panel of experts.

Design/methodology/approach

It is a cross-sectional descriptive study conducted in the field setting. A self-administered structured questionnaire was used to collect primary data from the respondents. This study follows an interpretive structural modeling (ISM) approach.

Findings

This study found that the factor “specific law for WB” has maximum driving power but minimum dependence and occupies bottom level (the most critical level) in the ISM model. The Matrice d’Impacts Croisés Multiplication Appliquée á un Classement analysis revealed that there is no autonomous and dependent factor in the model. There are eight linking factors and only one independent factor.

Research limitations/implications

The study found that the factor “specific law for WB” has maximum driving power but minimum dependence and occupies bottom level (the most critical level) in the ISM model. The Matrice d'Impacts Croisés Multiplication Appliquée á un Classement analysis revealed that there is no autonomous and no clear-cut dependent factor in the model. There are eight linking factors out of which five have high dependence as well, and there is only one independent factor.

Practical implications

This study has ensued in identification of significant challenging issues in WB and in development of interrelationships to gain insights into priority of these issues. This study uses limited primary data in context of Pakistan; therefore, generalizability of the findings is limited.

Originality/value

This study presents a novel theoretical and conceptual model focused on effective WB. The value of the study on effective WB is highly relevant for today’s complex organizations but incipient in literature. The insights provided by the study have vital importance for corporations to embark on the regime of reforms in CG.

Details

International Journal of Law and Management, vol. 62 no. 3
Type: Research Article
ISSN: 1754-243X

Keywords

Content available
Article

Yasmeen Al Balushi, Stuart Locke and Zakaria Boulanouar

This paper aims to investigate small and medium enterprises’ (SMEs) owner–managers’ awareness, willingness and perceptions concerning Islamic financing instruments as an…

Abstract

Purpose

This paper aims to investigate small and medium enterprises’ (SMEs) owner–managers’ awareness, willingness and perceptions concerning Islamic financing instruments as an alternative sourcing decision in SMEs’ businesses.

Design/methodology/approach

The research employed mixed methods to gather data. A questionnaire survey was conducted via face-to-face interviews with 385 SME owner–managers operating in Muscat, Oman’s capital city, along with face-to-face discussion on Islamic finance with 86 SME owner–managers. Descriptive and thematic analysis were used to analyse the data.

Findings

The findings indicate that SME owner–managers are aware of Islamic banking principles and have knowledge of Islamic financial instruments, despite Islamic finance being new to Oman. Interestingly, although the majority of the participants indicated their intention to adopt this new finance method, they were motivated by special requirements other than finance. Their positive perception of Islamic financing methods could play a significant role in developing the Islamic banking industry.

Research limitations/implications

The research is limited in that its data came only from Omani SME owner–managers in Muscat. Future research could investigate wider samples. Secondly, the study’s findings lack generalisability to larger and public enterprises, because only SME owner–managers were surveyed.

Practical implications

This study will be important for policy makers concerned about SMEs’ financing, Islamic financial institutions and new entrants into the Islamic banking industry, as it provides empirically evidence of Omanis’ views, and more specifically those of Omani SME owner–managers, on the recent introduction of Islamic finance into the country. The insights this study offers should help them to develop the strategies required to attract SMEs and to construct policies and regulations to improve Oman’s Islamic banking industry.

Originality/value

The research is significant, as it is the first study to investigate the awareness, willingness and perceptions of Omani SMEs regarding Islamic banking in Oman. Even though all Omanis are Muslims, Oman was the last of the six-nation Gulf Cooperation Council countries to introduce Islamic finance. Thus, this emerging market provides an important basis from which to extend future research on Islamic finance to other potential Islamic finance markets.

Details

Qualitative Research in Financial Markets, vol. 11 no. 4
Type: Research Article
ISSN: 1755-4179

Keywords

To view the access options for this content please click here
Article

Hassanudin Mohd Thas Thaker, Mohamed Asmy Mohd Thas Thaker, Ahmad Khaliq, Anwar Allah Pitchay and Hafezali Iqbal Hussain

This study aims to investigate the behavioural intention and adoption of internet banking (IB) among clients of local and foreign Islamic banks in Malaysia.

Abstract

Purpose

This study aims to investigate the behavioural intention and adoption of internet banking (IB) among clients of local and foreign Islamic banks in Malaysia.

Design/methodology/approach

Survey questionnaires were distributed among the Islamic banks’ clients at two main states, namely, Kuala Lumpur and Selangor. The number of clients involved is 319 (n = 319). The data was analysed using the partial least square (PLS) and theoretically, the research framework in this study is guided by the unified theory of acceptance and use of technology 2 (UTAUT2).

Findings

The smart PLS analysis yielded three main outcomes, namely, the variables such as performance expectancy, effort expectancy, price value, facilitating conditions and habit have a positive influence over the behavioural intention and subsequently lead to the adoption of IB. The other two variables, namely, social influence and hedonic motivation were negatively-related and insignificant for behavioural intention. Third, this paper also noticed that facilitating conditions and habits have a direct relationship with the adoption of IB.

Practical implications

Based on the findings, Islamic banks can take necessary action to design a better policy to further accelerate the usage of IB among their client. By identifying those factors, this, perhaps, can allow Islamic banks to invest more ideas on those significant factors that influence their interest, and subsequently leads to good business to Islamic banks as the clients nowadays are looking for simplicity and convenience factors when using IB.

Originality/value

This research is expected to enhance existing literature on internet banking, especially in Islamic banking research on the technological edge. Limited research has been done in Malaysia, particularly on the intention and continuous adoption of IB in Islamic banks using the UTAUT2 framework. This would be breakthrough research in identifying factors that influence customers’ continuous adoption of IB.

Details

Journal of Islamic Marketing, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0833

Keywords

To view the access options for this content please click here
Article

Moufida Ben Saada

This paper aims to explore the extent to which the control quality impacts non performing loans (NPLs) of Tunisian listed banks by integrating the guidelines of Circular…

Abstract

Purpose

This paper aims to explore the extent to which the control quality impacts non performing loans (NPLs) of Tunisian listed banks by integrating the guidelines of Circular No. 2011-06 issued on 20 May 2011 by Tunisian Central Bank.

Design/methodology/approach

Regressions using panel data are applied on a sample of 11 listed banks during the period from 2010 to 2015.

Findings

The results show that the presence of foreign directors on the Tunisian bank board affects credit risk. These administrators, with knowledge, independence and technology transfer, exercise more control than institutional administrators or state representatives. The risk committee is more effective than the other committees (audit committee and credit committee) in reducing non-performing loans. The role played by this body is the most important.

Practical implications

Testing empirically the impact of control quality on NPL by integrating the guidelines of the Central Bank leads to a better evaluation of reforms’ application and effective measures to strengthen the banking governance practices.

Originality value

By exploring the application of the Central Bank’s guidelines for strengthening post-revolutionary banking governance practices, it becomes easy to assess the extent of the Circular No. 2011-06 by accounting practitioners, auditors and authority bodies to give the necessary recommendations for further reforms.

Details

Managerial Auditing Journal, vol. 33 no. 1
Type: Research Article
ISSN: 0268-6902

Keywords

To view the access options for this content please click here
Article

Sabraz Nawaz Samsudeen, Gunapalan Selvaratnam and Ahamed Hilmy Hayathu Mohamed

This paper aims to identify the determinants of the intention to use mobile banking services among Islamic Banking customers in Sri Lanka. The study was carried out based…

Abstract

Purpose

This paper aims to identify the determinants of the intention to use mobile banking services among Islamic Banking customers in Sri Lanka. The study was carried out based on the Unified Theory of Acceptance and Use of Technology (UTAUT 2). The predictor variables of performance expectancy, effort expectancy, social influence, facilitating conditions, hedonic motivation and habit were used to predict the variable of behavioural intention to use. The moderating variables entail age, gender and experience.

Design/methodology/approach

Quantitative method with questionnaire survey was used. Data collection relied on the questionnaire survey method of which items were derived and adapted from past literatures. The responses were captured using the seven-point Likert scale. The study population consisted of Islamic Banking customers in Sri Lanka. A total of 594 questionnaires were returned of which 582 were found usable for analysis. Data analysis was conducted using the partial least square structural equation modelling along with SmartPLS 3.

Findings

The analysis results demonstrated the significant effect of all the variables on the Islamic Banking customers’ intention to use m-banking services along with the significant effect of the moderating variables as initially hypothesized.

Practical implications

As the first study of its kind in the context of Islamic banking customers in Sri Lanka, this study offers decision makers valuable guidelines for when they intend to re-engineer their m-banking applications and promote them to the public.

Originality/value

Following a comprehensive literature review, this study is identified as the pioneering effort in the investigation of m-banking usage intention among Islamic Banking customers in Sri Lanka. Therefore, this study contributes new knowledge and insights to the existing body of literature by confirming the viability of the UTAUT2 model in driving m-banking usage adoption among Islamic Banking customers in Sri Lanka.

Details

Journal of Islamic Marketing, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1759-0833

Keywords

1 – 10 of 17