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Functional Structure and Approximation in Econometrics
Type: Book
ISBN: 978-0-44450-861-4

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Article
Publication date: 7 May 2021

Sachin Kumar, Rajesh Kumar Gupta and Pinki Kumari

This study aims to find the symmetries and conservation laws of a new Painlevé integrable Broer-Kaup (BK) system with variable coefficients. This system is an extension of…

Abstract

Purpose

This study aims to find the symmetries and conservation laws of a new Painlevé integrable Broer-Kaup (BK) system with variable coefficients. This system is an extension of dispersive long wave equations. As the system is generalized and new, it is essential to explore some of its possible aspects such as conservation laws, symmetries, Painleve integrability, etc.

Design/methodology/approach

This paper opted for an exploratory study of a new Painleve integrable BK system with variable coefficients. Some analytic solutions are obtained by Lie classical method. Then the conservation laws are derived by multiplier method.

Findings

This paper presents a complete set of point symmetries without any restrictions on choices of coefficients, which subsequently yield analytic solutions of the series and solitary waves. Next, the authors derive every admitted non-trivial conservation law that emerges from multipliers.

Research limitations/implications

The authors have found that the considered system is likely to be integrable. So some other aspects such as Lax pair integrability, solitonic behavior and Backlund transformation can be analyzed to check the complete integrability further.

Practical implications

The authors develop a time-dependent Painleve integrable long water wave system. The model represents more specific data than the constant system. The authors presented analytic solutions and conservation laws.

Originality/value

The new time-dependent Painleve integrable long water wave system features some interesting results on symmetries and conservation laws.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 19 July 2021

Mohd Ann Amirul Zulffiqal Md Sahar, Zainuriah Hassan, Sha Shiong Ng, Way Foong Lim, Khai Shenn Lau, Ezzah Azimah Alias, Mohd Anas Ahmad, Nur Atiqah Hamzah and Rahil Izzati Mohd Asri

The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical…

Abstract

Purpose

The aims of this paper is to study the effects of the V/III ratio of indium gallium nitride (InGaN) quantum wells (QWs) on the structural, optical and electrical properties of near-ultraviolet light-emitting diode (NUV-LED).

Design/methodology/approach

InGaN-based NUV-LED is successfully grown on the c-plane patterned sapphire substrate at atmospheric pressure using metal organic chemical vapor deposition.

Findings

The indium composition and thickness of InGaN QWs increased as the V/III ratio increased from 20871 to 11824, according to high-resolution X-ray diffraction. The V/III ratio was also found to have an important effect on the surface morphology of the InGaN QWs and thus the surface morphology of the subsequent layers. Apart from that, the electroluminescence measurement revealed that the V/III ratio had a major impact on the light output power (LOP) and the emission peak wavelength of the NUV-LED. The LOP increased by up to 53% at 100 mA, and the emission peak wavelength of the NUV-LED changed to a longer wavelength as the V/III ratio decreased from 20871 to 11824.

Originality/value

This study discovered a relation between the V/III ratio and the properties of QWs, which resulted in the LOP enhancement of the NUV-LED. High TMIn flow rates, which produced a low V/III ratio, contribute to the increased LOP of NUV-LED.

Details

Microelectronics International, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1356-5362

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Article
Publication date: 27 July 2021

Shuwen Guo, Junwu Wang and Han Wu

This paper examines the profit distribution of engineering projects in the integrated project delivery (IPD) mode. IPD is a new delivery method that can ameliorate many of…

Abstract

Purpose

This paper examines the profit distribution of engineering projects in the integrated project delivery (IPD) mode. IPD is a new delivery method that can ameliorate many of the disadvantages of traditional delivery methods and improve project results. In the implementation of IPD, the profit distribution is key for ensuring the success of IPD projects.

Design/methodology/approach

This paper described a new method for characterizing profit distribution in the IPD mode. The payment function and Shapley value of the cooperative fuzzy game of fuzzy alliance were defined by considering the Choquet integral of the fuzzy measure. The participation of each player was considered, and the influence of participation on the profit distribution was discussed. Lastly, changes in the profit distribution of core participants under different alliance combinations were studied.

Findings

A case from a report of The American Institute of Architects (AIA) was used to verify the fuzzy alliance model. There was a significant correlation between the degree of participation of the owner, architect and builder and the profit distribution among these three participants.

Research limitations/implications

The theoretical research in this paper has some limitations. Initially, this paper selects a case with only three key participants in order to simplify the research. When there are many core participants, how to establish the alliance in the IPD mode and how to establish the corresponding profit distribution model, further work is certainly required to disentangle these complexities in models. Second, in this case, BIM technology has little impact on the income of the whole project. Therefore, this paper does not consider the impact of BIM technology on the marginal effect of the IPD project. Third, the contract type in the case is a custom tri-party based on IFOA. There is no classified discussion of the impact of different contracts on the profit distribute in the paper.

Practical implications

Based on the in-depth study of cooperative game with alliance structure, this paper promotes the classic cooperative game with alliance structure. The authors define the payoff function of fuzzy cooperative games by Choquet integral of fuzzy measure, and introduce the idea into the field of IPD. It aims at extending the solution to a cooperative game without a core. It can be obtained through a simple calculation. In the IPD alliance, the fuzziness and uncertainty of the participation degree of each participant will affect the profit of the whole project. The authors find that the higher the participation rate of players, the more profit each participant has. The greater the influence weight of the designer on the alliance, the lower the influence weight of the contractor on the alliance, the lower the participation of the contractor and the designer, and the lower the income distribution value of the three core participants. It shows a monotonous decline status.

Social implications

For any construction enterprise, it can make more profits if it joins the grand alliance. In the IPD alliance, each participant can maximize their own interests, which can also promote the enthusiasm of construction enterprises to participate in the alliance and increase the application of IPD mode in AEC industry. This research method provides a new fast, effective, and more realistic solution method for cooperative countermeasures. It can be further extended to other cooperative game fields and advance a new research perspective and solution for the distribution of cooperative interests.

Originality/value

The contribution of this paper is the development of a fuzzy alliance model that provides a tool for measuring the profit distribution in IPD. This is the first quantitative model to connect the degree of participation with the profit distribution in IPD using fuzzy alliance.

Details

Engineering, Construction and Architectural Management, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 22 July 2021

Elliot Smith, Richard Stevenson, Leah Dudley and Heather Francis

Greater fruit and vegetable (F&V) intake has been linked to more positive mood. Here, the purpose of this paper is to examine if this relationship is mediated by…

Abstract

Purpose

Greater fruit and vegetable (F&V) intake has been linked to more positive mood. Here, the purpose of this paper is to examine if this relationship is mediated by expectancies about their benefit to health/mental health.

Design/methodology/approach

Participants completed a new questionnaire to assess expectancies related to F&V intake. This was administered alongside a validated food-frequency measure of F&V intake, an assessment of positive and negative mood state and other measures.

Findings

Participants held strongly positive expectations about the physical and mental health benefits of consuming F&V. The authors observed a significant relationship between self-reported F&V intake and positive mood (d = 0.52). Importantly, this effect was largely (but not completely) independent of expectancies. The authors also observed that expectancies about F&V intake were independently predictive of positive mood (d = 0.47).

Originality/value

This is the first study to explore expectancy effects in the mental health benefits of F&V intake. These data suggest that positive expectancies about F&V intake, and F&V intake itself, are both predictive of positive mood. The former finding is probably a placebo effect, whereby people believe they are consuming sufficient F&V (even if they are not) and so experience mood-related benefits due to their positive expectations. The latter finding is consistent with F&V exerting a biologically beneficial effect on the brain.

Details

British Food Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0007-070X

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Article
Publication date: 22 July 2021

Bernd Engelmann

The purpose of this article is to derive formulas for lifetime expected credit loss of loans that are required for the calculation of loan loss reserves under IFRS 9. This…

Abstract

Purpose

The purpose of this article is to derive formulas for lifetime expected credit loss of loans that are required for the calculation of loan loss reserves under IFRS 9. This is done both for fixed-rate and floating rate loans under different assumptions on LGD modeling, prepayment, and discount rates.

Design/methodology/approach

This study provides exact formulas for lifetime expected credit loss derived analytically together with the mathematical proofs of each expression.

Findings

This articles shows that the formula most commonly applied in the literature for calculating lifetime expected credit loss is inconsistent with measuring expected loss based on expected discounted cash flows. Formulas based on discounted cash flows always lead to more conservative numbers.

Practical implications

For banks reporting under IFRS 9, the implication of this research is a better understanding of the different approaches used for computing lifetime expected loss, how they are connected, and what assumptions are underlying each approach. This may lead to corrections in existing frameworks to make applications of risk management systems more consistent.

Originality/value

While there is a lot of literature explaining IFRS 9 and evaluating its impact, none of the existing research has systematically analyzed the calculation of lifetime expected credit loss for this purpose and how the formula changes under different modeling assumptions. This gap is filled by this study.

Details

The Journal of Risk Finance, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1526-5943

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Article
Publication date: 29 July 2021

A. A. Alanazi, Sultan Z. Alamri, S. Shafie and Shazirawati Mohd Puzi

The purpose of this paper is to obtain the nonlinear Schrodinger equation (NLSE) numerical solutions in the presence of the first-order chromatic dispersion using a…

Abstract

Purpose

The purpose of this paper is to obtain the nonlinear Schrodinger equation (NLSE) numerical solutions in the presence of the first-order chromatic dispersion using a second-order, unconditionally stable, implicit finite difference method. In addition, stability and accuracy are proved for the resulting scheme.

Design/methodology/approach

The conserved quantities such as mass, momentum and energy are calculated for the system governed by the NLSE. Moreover, the robustness of the scheme is confirmed by conducting various numerical tests using the Crank-Nicolson method on different cases of solitons to discuss the effects of the factor considered on solitons properties and on conserved quantities.

Findings

The Crank-Nicolson scheme has been derived to solve the NLSE for optical fibers in the presence of the wave packet drift effects. It has been founded that the numerical scheme is second-order in time and space and unconditionally stable by using von-Neumann stability analysis. The effect of the parameters considered in the study is displayed in the case of one, two and three solitons. It was noted that the reliance of NLSE numeric solutions properties on coefficients of wave packets drift, dispersions and Kerr nonlinearity play an important control not only the stable and unstable regime but also the energy, momentum conservation laws. Accordingly, by comparing our numerical results in this study with the previous work, it was recognized that the obtained results are the generalized formularization of these work. Also, it was distinguished that our new data are regarding to the new communications modes that depend on the dispersion, wave packets drift and nonlinearity coefficients.

Originality/value

The present study uses the first-order chromatic. Also, it highlights the relationship between the parameters of dispersion, nonlinearity and optical wave properties. The study further reports the effect of wave packet drift, dispersions and Kerr nonlinearity play an important control not only the stable and unstable regime but also the energy, momentum conservation laws.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 26 July 2021

Vikash Gurugubelli and Arnab Ghosh

The share of renewable energy sources (RESs) in the power system is increasing day by day. The RESs are intermittent, therefore maintaining the grid stability and power…

Abstract

Purpose

The share of renewable energy sources (RESs) in the power system is increasing day by day. The RESs are intermittent, therefore maintaining the grid stability and power balance is very difficult. The purpose of this paper is to control the inverters in microgrid using different control strategies to maintain the system stability and power balance.

Design/methodology/approach

In this paper, different control strategies are implemented to the voltage source converter (VSC) to get the desired performance. The DQ control is a basic control strategy that is inherently present in the droop and virtual synchronous machine (VSM) control strategies. The droop and VSM control strategies are inspired by the conventional synchronous machine (SM). The main objective of this work is to design and implement the three aforementioned control strategies in microgrid.

Findings

The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy.

Research limitations/implications

In the power system, the power electronic-based power allowed by VSM is dominated by the conventional power which is generated from the traditional SM, and then the issues related to stability still need advance study. There are some differences between the SM and VSM characteristics, so the integration of VSM with the existing system still needs further study. Economical operation of VSM with hybrid storage is also one of the future scopes of this work.

Originality/value

The significant contributions of this work are: the detailed implementation of DQ control, droop control and VSM control strategies for VSC in both grid-connected mode and standalone mode is presented; the MATLAB/Simulink simulation results and comparative studies of the three aforementioned controllers are introduced first time in the proposed work; and the opal-RT digital real-time simulation results of the proposed VSM control show the superiority in transient response compared to the droop control strategy.

Details

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

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Article
Publication date: 31 December 2020

Kapil Bhardwaj and Mayank Srivastava

This paper aims to develop a mathematical model for four-lobe memristor (FLM) element. The four-lobe memristive behaviour can be used in realization of hyperchaotic…

Abstract

Purpose

This paper aims to develop a mathematical model for four-lobe memristor (FLM) element. The four-lobe memristive behaviour can be used in realization of hyperchaotic oscillators and implementation of multi-bit memories. For verification of the developed mathematical framework, two FLM circuit emulators have been presented using VDCC and IC LM13700, respectively.

Design/methodology/approach

A mathematical model for FLM has been developed in which, the condition for the existence of symmetrical four lobes, instances and coordinates of the end points of lobes has been derived and presented. Using this mathematical framework, a FLM emulator based on VDCC has been developed. To validate the possibility of practical implementation of FLM concept, an IC LM13700-based circuit has also been developed. The workability of VDCC based circuit has been verified by running simulations in PSPICE environment using CMOS VDCC model. Similarly, the behaviour of LM13700 IC-based circuit has been confirmed by SPICE model of LM13700 IC.

Findings

It has been shown mathematically that under certain conditions, third-order flux dependent equation of memductance can be used to generate four lobes on the transient v-i plane. Also, two FLM emulators without using any voltage multiplier circuit/IC have been reported.

Originality/value

From the best knowledge of the authors, there are no such FLM emulators that have been reported in literature so far, which operates at practical operating frequencies.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering , vol. 40 no. 1
Type: Research Article
ISSN: 0332-1649

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Abstract

Details

Functional Structure and Approximation in Econometrics
Type: Book
ISBN: 978-0-44450-861-4

1 – 10 of over 217000