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1 – 10 of over 15000
Article
Publication date: 6 February 2017

Yi-Chung Hu

Energy demand is an important economic index, and demand forecasting has a significant role when devising energy development plans for cities or countries. GM(1,1) model has…

Abstract

Purpose

Energy demand is an important economic index, and demand forecasting has a significant role when devising energy development plans for cities or countries. GM(1,1) model has become popular because it needs only a few data points to construct a time-series model without statistical assumptions. Several methods have been developed to improve prediction accuracy of the original GM(1,1) model by only estimating the sign of each residual. This study aims to address that this is too tight a restriction for the modification range.

Design/methodology/approach

Based on the predicted residual, this study uses the functional-link net (FLN) with genetic-algorithm-based learning to estimate the modification range for its corresponding predicted value obtained from the original GM(1,1) model.

Findings

The forecasting ability of the proposed grey prediction model is verified using real energy demand cases from China. Experimental results show that the proposed prediction model performs well compared to other grey residual modification models with sign estimation.

Originality/value

The proposed FLNGM(1,1) model can improve prediction accuracy of the original GM(1,1) model using residual modification. The distinctive feature of the proposed model is to use an FLN to estimate sign and modification range simultaneously for the predicted value based on its corresponding predicted residual obtained from the residual GM(1,1) model.

Details

Kybernetes, vol. 46 no. 2
Type: Research Article
ISSN: 0368-492X

Keywords

Article
Publication date: 28 August 2009

Marie‐Paule Laurent, Mathias Schmit and Suk Chun Van Belle

The purpose of this paper is to examine residual value risk modelling issues with a focus on automotive lease portfolios. Residual value risk is approached through a re‐sampling…

1082

Abstract

Purpose

The purpose of this paper is to examine residual value risk modelling issues with a focus on automotive lease portfolios. Residual value risk is approached through a re‐sampling technique that provides the probability density function of losses and VaR measures for credit portfolios.

Design/methodology/approach

The methodology is applied to a portfolio of 37,523 operating leases issued between 1989 and 2001 by a major European financial institution.

Findings

The results show that residual value losses are low and sometimes non‐existent. Moreover, the major part of residual value risk is idiosyncratic and can thus be eliminated through adequate diversification. Additionally, this internal model seems to prove that capital requirements stemming from the Basel Committee's proposed new framework are somehow overestimated.

Originality/value

This paper advocates determining a more accurate risk weight for residual value risk in order to better reflect this relatively low‐risk part of leasing activities.

Details

Managerial Finance, vol. 35 no. 10
Type: Research Article
ISSN: 0307-4358

Keywords

Article
Publication date: 24 August 2012

Gulshan Singh, Juan Ocampo, Harry Millwater and Allan Clauer

The purpose of this paper is to develop an approach to optimize the cycles‐to‐failure of a peened component with respect to laser peening (LP) variables: pressure magnitude…

Abstract

Purpose

The purpose of this paper is to develop an approach to optimize the cycles‐to‐failure of a peened component with respect to laser peening (LP) variables: pressure magnitude, mid‐span, and spot size when the component is subject to a variable amplitude loading.

Design/methodology/approach

To optimally design an LP process, an experimentally validated 3D finite element simulation of the LP process, a cycles‐to‐failure estimation capability incorporating residual stress, and a particle swarm optimization strategy were developed and employed to maximize the cycles‐to‐failure of a component of a titanium turbine disk.

Findings

The most critical finding of this research is that a minor difference in the residual stress profile can lead to a large difference in the cycles‐to‐failure. This finding implies that selecting the optimization objective to be the cycles‐to‐failure is a better option as compared to the residual stress profile.

Research limitations/implications

The LP‐induced residual stresses are assumed static and do not change as number of load cycles increase.

Originality/value

The paper develops a framework that relates the LP variables and the cycles‐to‐failure of a peened component. A modified particle swarm optimization approach is developed to optimize the fatigue life of a turbine disk.

Article
Publication date: 20 September 2011

Rufus Ayodeji Olowe

This paper aims to investigate the impact of the introduction of the 2004 bank capital requirements on the quoted stock prices on the Nigerian stock market.

Abstract

Purpose

This paper aims to investigate the impact of the introduction of the 2004 bank capital requirements on the quoted stock prices on the Nigerian stock market.

Design/methodology/approach

Using monthly data over the period January 1986 to December 2006, residual analysis methodology was used to investigate stock price reaction to the 2004 bank capital requirements on the Nigerian stock market.

Findings

The results show that the introduction of the 2004 bank capital requirements has a positive impact on quoted securities on the Nigerian stock market. This is reflected in positive abnormal returns from the Nigerian stock market when trading is based on the information from the 2004 bank capital requirements. The results are unaffected by the choice of model. This lends support for the work of Olowe that the Nigerian stock market is inefficient in the semi‐strong form.

Originality/value

This study provides evidence on the stock price reaction to the introduction of the 2004 bank capital requirements on the Nigerian stock market. The result will have implications for the semi‐strong form efficiency of the Nigerian stock market.

Details

African Journal of Economic and Management Studies, vol. 2 no. 2
Type: Research Article
ISSN: 2040-0705

Keywords

Open Access
Article
Publication date: 4 August 2020

Akram Ramadan Budagaga

This study will examine the impact of cash dividends on the market value of banks listed in Middle East and North African (MENA) emerging countries during the period 2000–2015.

4624

Abstract

Purpose

This study will examine the impact of cash dividends on the market value of banks listed in Middle East and North African (MENA) emerging countries during the period 2000–2015.

Design/methodology/approach

The current study adopts residual income approach based on Ohlson's (1995) valuation model. By testing different statistical techniques, fixed effect is applied on panel data for (144) banks listed on 11 MENA stock markets over the period 2000–2015. Furthermore, additional tests are applied to confirm the primary results.

Findings

The analysis reveals that current dividend payouts and dividend yield do not provide information relevant to the establishment of market values in MENA emerging markets; thus, they have no material impact on MENA banks' market values. This lack of current dividend payment effect is consistent with Miller and Modigliani (1961) dividend irrelevance assumption: there is no evidence of either an informational or real cash inflow effect of current dividend payments. The findings of this study can be attributed to the fact that MENA banks may be forced to place more emphasis on allocating money for investment instead of paying dividends given them they are subject to liquidity requirements for investment, expansion, general operations and compliance with regulations. Only after all these financial needs are covered can the remaining surplus be distributed as cash dividends. Therefore, cash dividends represent earnings residual rather than an active decision variable that impacts a firm's market value. This is consistent with the residual dividend hypothesis, which is the crux of Miller and Modigliani (1996) irrelevance theory of dividends.

Research limitations/implications

The current study is restricted to a sample of one type of financial firms, banks, because of the problem of missing data and limited information related to other financial firms for the same period. Therefore, further research could be additional types of financial firms such as insurance firms that play a vital role in MENA emerging economies.

Practical implications

The results of this study have some important implications for banks' dividend policymakers. Dividend policymakers in MENA emerging markets seem to follow residual dividend policy, in which they distribute dividends according to what is left over after all acceptable investment opportunities have been undertaken. This makes for inconsistent and unstable dividend policy trends, making it difficult for investors to predict future dividend decisions. Further, this practice may deliver information to shareholders about a lack of positive future investment opportunities, and this may negatively affect the share value of banks.

Originality/value

This study is the first of its kind – up to the author's knowledge – that examines a large cross-country sample of MENA banks (144) to cover a long time period in the recent past, and, more importantly, after the banking sector in the region has experienced major transformations during last two decades. In addition, most of the MENA region countries included in this study, namely, banks, operate in tax-free environments (there are neither taxes on dividends nor on capital gains). This feature adds complexity to the ongoing dividend debate.

Details

Journal of Capital Markets Studies, vol. 4 no. 1
Type: Research Article
ISSN: 2514-4774

Keywords

Article
Publication date: 9 March 2015

Christophe Letot, Pierre Dehombreux, Edouard Rivière-Lorphèvre, Guillaume Fleurquin and Arnaud Lesage

The purpose of this paper is to highlight the need for degradation data in order to improve the reliability and the mean residual life estimation of a specific item of equipment…

Abstract

Purpose

The purpose of this paper is to highlight the need for degradation data in order to improve the reliability and the mean residual life estimation of a specific item of equipment and to adapt the preventive maintenance tasks accordingly.

Design/methodology/approach

An initial reliability model which uses a degradation-based reliability model that is built from the collection of hitting times of a failure threshold. The proposed maintenance model is based on the cost/availability criterion. The estimation of both reliability and optimum time for preventive maintenance are updated with all new degradation data that are collected during operating time.

Findings

An improvement for the occurrences of maintenance tasks which minimizes the mean cost per unit of time and increases the availability.

Practical implications

Inspection tasks to measure the degradation level should be realized at least one time for each item of equipment at a specific time determined by the proposed methodology.

Originality/value

The introduction of a criterion which helps the maintainer to decide to postpone or not the preventive replacement time depending on the measured degradation level of a specific item of equipment.

Details

Journal of Quality in Maintenance Engineering, vol. 21 no. 1
Type: Research Article
ISSN: 1355-2511

Keywords

Article
Publication date: 5 July 2011

Takaya Inamori, Nobutada Sako and Shinichi Nakasuka

This paper aims to present an attitude determination and control system for a nano‐astrometry satellite which requires precise angular rate control. Focus of the research is…

Abstract

Purpose

This paper aims to present an attitude determination and control system for a nano‐astrometry satellite which requires precise angular rate control. Focus of the research is methods to achieve the requirement.

Design/methodology/approach

In order to obtain astrometry data, the satellite attitude should be controlled to an accuracy of 0.05°. Furthermore, attitude spin rate must be controlled to an accuracy of 4×10−7 rad/s during observation. In this paper the following unique ideas to achieve these requirements are introduced: magnetic disturbance compensation and rate estimation using star blurred images.

Findings

This paper presents the feasibility of a high accurate attitude control system in nano‐ and micro‐satellite missions.

Practical implications

This paper presents a possibility of the application of nano‐satellites to remote‐sensing and astronomy mission, which requires accurate attitude control.

Originality/value

Originalities of the paper are the methods to achieve the high accurate attitude control: magnetic disturbance compensation and angular rate estimation using star images.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 4
Type: Research Article
ISSN: 0002-2667

Keywords

Article
Publication date: 19 July 2021

Mohammad Qasim Shaikh, Serena Graziosi and Sundar Vedanarayan Atre

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF3) of Ti-6Al-4V. Additionally, an empirical…

513

Abstract

Purpose

This paper aims to investigate the feasibility of supportless printing of lattice structures by metal fused filament fabrication (MF3) of Ti-6Al-4V. Additionally, an empirical method was presented for the estimation of extrudate deflection in unsupported regions of lattice cells for different geometric configurations.

Design/methodology/approach

Metal-polymer feedstock with a solids-loading of 59 Vol.% compounded and extruded into a filament was used for three-dimensional printing of lattice structures. A unit cell was used as a starting point, which was then extended to multi-stacked lattice structures. Feasible MF3 processing conditions were identified to fabricate defect-free lattice structures. The effects of lattice geometry parameters on part deflection and relative density were investigated at the unit cell level. Computational simulations were used to predict the part quality and results were verified by experimental printing. Finally, using the identified processing and geometry parameters, multi-stacked lattice structures were successfully printed and sintered.

Findings

Lattice geometry required considerable changes in MF3 printing parameters as compared to printing bulk parts. Lattice cell dimensions showed a considerable effect on dimensional variations and relative density due to varying aspect ratios. The experimental printing of lattice showed large deflection/sagging in unsupported regions due to gravity, whereas simulation was unable to estimate such deflection. Hence, an analytical model was presented to estimate extrudate deflections and verified with experimental results. Lack of diffusion between beads was observed in the bottom facing surface of unsupported geometry of sintered unit cells as an effect of extrudate sagging in the green part stage. This study proves that MF3 can fabricate fully dense Ti-6Al-4V lattice structures that appear to be a promising candidate for applications where mechanical performance, light-weighting and design customization are required.

Originality/value

Supportless printing of lattice structures having tiny cross-sectional areas and unsupported geometries is highly challenging for an extrusion-based additive manufacturing (AM) process. This study investigated the AM of Ti-6Al-4V supportless lattice structures using the MF3 process for the first time.

Article
Publication date: 19 November 2019

Pengcheng Wang, Dengfeng Zhang and Baochun Lu

This paper aims to address the collision problem between robot and the external environment (including human) in an unstructured situation. A new collision detection and torque…

Abstract

Purpose

This paper aims to address the collision problem between robot and the external environment (including human) in an unstructured situation. A new collision detection and torque optimization control method is proposed.

Design/methodology/approach

Firstly, when the collision appears, a second-order Taylor observer is proposed to estimate the residual value. Secondly, the band-pass filter is used to reduce the high-frequency torque modeling dynamic uncertainty. With the estimate information and the torque value, a variable impedance control approach is then synthesized to guarantee that the collision is avoided or the collision will be terminated with different contact models and positions. However, in terms of adaptive linear force error, the variation of the thickness of the boundary layer is controlled by the new proximity function.

Findings

Finally, the experimental results show the better performance of the proposed control method, realizing the force control during the collision process.

Originality/value

Origin approach and origin experiment.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 6
Type: Research Article
ISSN: 0143-991X

Keywords

Article
Publication date: 1 August 2001

Jaroslav Mackerle

Gives a bibliographical review of the error estimates and adaptive finite element methods from the theoretical as well as the application point of view. The bibliography at the…

1666

Abstract

Gives a bibliographical review of the error estimates and adaptive finite element methods from the theoretical as well as the application point of view. The bibliography at the end contains 2,177 references to papers, conference proceedings and theses/dissertations dealing with the subjects that were published in 1990‐2000.

Details

Engineering Computations, vol. 18 no. 5/6
Type: Research Article
ISSN: 0264-4401

Keywords

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