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1 – 10 of over 24000Ratree Kummong and Siriporn Supratid
An accurate long-term multi-step forecast provides crucial basic information for planning and reinforcing managerial decision-support. However, nonstationarity and nonlinearity…
Abstract
Purpose
An accurate long-term multi-step forecast provides crucial basic information for planning and reinforcing managerial decision-support. However, nonstationarity and nonlinearity, normally consisted of several types of managerial data can seriously ruin the forecasting computation. This paper aims to propose an effective long-term multi-step forecasting conjunction model, namely, wavelet–nonlinear autoregressive neural network (WNAR) conjunction model. The WNAR combines discrete wavelet transform (DWT) and nonlinear autoregressive neural network (NAR) to cope with such nonstationarity and nonlinearity within the managerial data; as a consequence, provides insight information that enhances accuracy and reliability of long-term multi-step perspective, leading to effective management decision-making.
Design/methodology/approach
Based on WNAR conjunction model, wavelet decomposition is executed for efficiently extracting hidden significant, temporal features contained in each of six benchmark nonstationary data sets from different managerial domains. Then, each extracted feature set at a particular resolution level is fed into NAR for the further forecast. Finally, NAR forecasting results are reconstructed. Forecasting performance measures throughout 1 to 30-time lags rely on mean absolute percentage error (MAPE), root mean square error (RMSE), Nash-Sutcliffe efficiency index or the coefficient of efficiency (Ef) and Diebold–Mariano (DM) test. An effect of data characteristic in terms of autocorrelation on forecasting performances of each data set are observed.
Findings
Long-term multi-step forecasting results show the best accuracy and high-reliability performance of the proposed WNAR conjunction model over some other efficient forecasting models including a single NAR model. This is confirmed by DM test, especially for the short-forecasting horizon. In addition, rather steady, effective long-term multi-step forecasting performances are yielded with slight effect from time lag changes especially for the data sets having particular high autocorrelation, relative against 95 per cent degree of confidence normal distribution bounds.
Research limitations/implications
The WNAR, which combines DWT with NAR can be accounted as a bridge for the gap between machine learning, engineering signal processing and management decision-support systems. Thus, WNAR is referred to as a forecasting tool that provides insight long-term information for managerial practices. However, in practice, suitable exogenous input forecast factors are required on the managerial domain-by-domain basis to correctly foresee and effectively prepare necessary reasonable management activities.
Originality/value
Few works have been implemented to handle the nonstationarity, consisted of nonlinear managerial data to attain high-accurate long-term multi-step forecast. Combining DWT and NAR capabilities would comprehensively and specifically deal with the nonstationarity and nonlinearity difficulties at once. In addition, it is found that the proposed WNAR yields rather steady, effective long-term multi-step forecasting performance throughout specific long time lags regarding the data, having certainly high autocorrelation levels across such long time lags.
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The vehicle sideslip angle is an important state of vehicle lateral dynamics and its knowledge is crucial for the successful implementation of advanced driver-assistance systems…
Abstract
Purpose
The vehicle sideslip angle is an important state of vehicle lateral dynamics and its knowledge is crucial for the successful implementation of advanced driver-assistance systems. Measuring the vehicle sideslip angle on a production vehicle is challenging because of the exorbitant price of a physical sensor. This paper aims to present a novel framework for virtually sensing/estimating the vehicle sideslip angle. The desired level of accuracy for the estimator is to be within +/− 0.2 degree of the actual sideslip angle of the vehicle. This will make the precision of the proposed estimator at par with expensive commercially available sensors used for physically measuring the vehicle sideslip angle.
Design/methodology/approach
The proposed estimator uses an adaptive tire model in conjunction with a model-based observer. The performance of the estimator is evaluated through experimental tests on a rear-wheel drive vehicle.
Findings
Detailed experimental results show that the developed system can reliably estimate the vehicle sideslip angle during both steady state and transient maneuvers, within the desired accuracy levels.
Originality/value
This paper presents a novel framework for vehicle sideslip angle estimation. The presented framework combines an adaptive tire model, an unscented Kalman filter-based axle force observer and data from tire mounted sensors. Tire model adaptation is achieved by making extensions to the magic formula, by accounting for variations in the tire inflation pressure, load, tread-depth and temperature. Predictions with the adapted tire model were validated by running experiments on the Flat-Trac® machine. The benefits of using an adaptive tire model for sideslip angle estimation are demonstrated through experimental tests. The performance of the observer is satisfactory, in both transient and steady state maneuvers. Future work will focus on measuring tire slip angle and road friction information using tire mounted sensors and using that information to further enhance the robustness of the vehicle sideslip angle observer.
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John P. Spillane and Lukumon O. Oyedele
The purpose of this paper is to identify best practice relating to the effective management of materials in an urban, confined construction site, using structural equation…
Abstract
Purpose
The purpose of this paper is to identify best practice relating to the effective management of materials in an urban, confined construction site, using structural equation modelling.
Design/methodology/approach
A literature review, case study analysis and questionnaire survey are used, with the results scrutinised using confirmatory factor analysis in the form of structural equation modelling.
Findings
The following are the leading strategies in the management of materials in a confined urban site environment: consult and review the project programme, effective communication and delivery, implement site safety management plans and proactive spatial monitoring and control.
Research limitations/implication
With the relentless expansion of urban centres and the increasing high cost of materials, any potential savings made on-site would translate into significant monetary concessions on completion of a project.
Originality/value
As on-site project management professionals successfully identify and implement the various strategies in the management of plant and materials on a confined urban site, successful resource management in this restrictive environment is attainable.
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Many banks and financial institutions have resisted the opportunity to model customer profiles because of the cost of developing and maintaining customer profitability information…
Abstract
Many banks and financial institutions have resisted the opportunity to model customer profiles because of the cost of developing and maintaining customer profitability information based on the capture and storage of individual transactions. This paper describes the development of such a model to calculate customer profitability, by putting into place systems which allow the capture and analysis of accurate, up‐to‐date information regarding the transactions of individual customers. The implementation of the model within one regional Australian bank is detailed, together with an indication of its potential for operational and strategic decision making. We speculate that such a model might be more widely adopted to allow banks to focus effectively on the most profitable segments of their business.
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Ge Song, Tor Bjørge, Jens Holen and Bjørn F. Magnussen
Reports that major advances have been achieved on computational simulations of multidimensional fluid flow, heat and mass transfer during the last 20 years. Focuses on the…
Abstract
Reports that major advances have been achieved on computational simulations of multidimensional fluid flow, heat and mass transfer during the last 20 years. Focuses on the numerical prediction of fluid flow, combustion and gas radiation in a combustion chamber of a typical industrial glass‐melting furnace. Carries out the flow simulation in a three‐dimensional calculation domain by using computer models in conjunction with the standard k ‐ ε turbulence model. Tests the predictions of spectral intensity by solving the equation of radiative transfer. Employs the Goody statistical narrow band model with the Curtis‐Godson approximation to calculate radiative properties for inhomogeneous gas mixtures.
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The paper aims to address concerns that valuers' choice of depreciation models in their cost approach to value is not sustainable (is incapable of preserving patronage in present…
Abstract
Purpose
The paper aims to address concerns that valuers' choice of depreciation models in their cost approach to value is not sustainable (is incapable of preserving patronage in present and future generations).
Design/methodology/approach
The paper draws up conceptual expectations regarding how seven UK and US depreciation models pass or fail four identified sustainability indicators: reliability, consistency, usability and separate treatment of depreciation components. Valuation surveyors in Nigeria were offered as a case study of how valuers in one country respond to such conceptual investigations.
Findings
The study found that cross‐sectional models, the breakdown model and hedonic modeling are the depreciation models perceived as most sustainable. However, popular model use follows easiest models rather than most sustainable models.
Practical implications
The paper suggests that the pursuit of sustainability in valuation modeling should involve provision of institutionalized best practice guidance beyond that currently provided so as to assist valuers/appraisers in more sustainable choices.
Originality/value
The paper is probably the first to address both UK and US depreciation models and to assess each using defined sustainability criteria.
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Michael Peshkin and J. Edward Colgate
Collaborative robots – “cobots” – are intended for direct interaction with a human worker, handling a shared payload. They are a marked departure from autonomous industrial robots…
Abstract
Collaborative robots – “cobots” – are intended for direct interaction with a human worker, handling a shared payload. They are a marked departure from autonomous industrial robots which must be isolated from people for safety reasons. Cobots are also distinct from teleoperators, in which a human operator controls a robot and payload remotely. Cobots interact with people by producing software‐defined “virtual surfaces” which constrain and guide the motion of the shared payload, but add little or no power. Ergonomic as well as productivity benefits result from combining the strength and computer‐interface of the cobot with the sensing and dexterity of the human worker. This paper explains cobots as one approach to an emerging class of materials handling equipment called Intelligent Assist Devices (IADs). We describe two cobots of this class presently in industrial testbed settings. Future applications of cobots’ virtual surfaces are tool guidance in image guided surgery, and haptic display in which the surfaces of a CAD model can be felt.
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Jaekwon Chung and Dong Li
The purpose of this study is to compare the impact of multi‐period pricing, as an example of more dynamic pricing and discounting strategy with that of a present less dynamic…
Abstract
Purpose
The purpose of this study is to compare the impact of multi‐period pricing, as an example of more dynamic pricing and discounting strategy with that of a present less dynamic alternative on customer satisfaction and consumers' willingness to make trade‐offs between price and remaining shelf‐life.
Design/methodology/approach
The authors conducted interviews with three food retail managers in South Korea to gather practical information about the management of perishable foods, which informed the design of a survey in which consumers in South Korea were questioned about their perceptions of the two strategies, with respect to nine perishable food products in three categories. The data collected were analysed by one‐way ANOVA and the t‐test.
Findings
The findings of this research present an improved understanding of the impact of a multi‐period pricing strategy on consumer satisfaction and customer behaviour for perishable foods. The conclusions have the potential to significantly assist food retailers to understand the consumers' perspective on the benefits of a more dynamic pricing strategy.
Practical implications
The findings suggest that food retailers can enhance customer satisfaction by offering an earlier but lower discount, and increasing it as perishable food items approach their expiry date, rather than a higher discount when the expiry date is imminent.
Originality/value
The findings in this study are significant since they serve as the first step in measuring the value of dynamic pricing approaches that provide better trade‐off options between price and remaining shelf‐life from consumers' perspectives.
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Gu Xin, Xiao-Ri Liu, Dong-Kang Cheng, Qing-Ping Zheng, Meng-Han Li, Nan-Nan Sun and Chun-Hua Min
This paper aims to investigate the effect of lubricant viscosity model with improver on friction and lubrication of piston skirt-cylinder liner conjunction.
Abstract
Purpose
This paper aims to investigate the effect of lubricant viscosity model with improver on friction and lubrication of piston skirt-cylinder liner conjunction.
Design/methodology/approach
A dynamic calculation model is established for the piston skirt-cylinder liner conjunction of a heavy-duty commercial diesel engine, to explore the effects of two kinds of lube oil viscosity models named after polyalkyle-metacrylate-1 (PAMA1) and styrene-isoprene-copolymer (SICP) improvers on the maximum oil film viscosity, the minimum oil film thickness, the peak oil film pressure, the maximum shear rate, the friction force and the total friction power loss.
Findings
The variation trends with the crank angle of the above parameters are not changed with the difference of improvers, while obvious numerical differences are found except the maximum oil film pressure. The minimum oil film thickness and maximum shear rate of PAMA1 are larger than that of SICP, the maximum oil film viscosity of SICP is larger than that of PAMA1, which indicates that the shear-thinning effect of PAMA1 is greater, the maximum friction force on the piston of SICP is larger than that of PAMA1, and the total friction power consumption is also larger, the average friction power consumptions of SICP and PAMA1 are 385.4 and 262.8 W, respectively, with the relative difference of 31.8 per cent.
Originality/value
The influence of different lubricating oil additive models on the lubrication and friction of piston skirt-cylinder liner conjunction is simulated and analyzed.
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