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1 – 10 of over 196000Masatoshi Muramatsu and Takeo Kato
The purpose of this paper is to propose the selection guide of the multi-objective optimization methods for the ergonomic design. The proposed guide enables designers to select an…
Abstract
Purpose
The purpose of this paper is to propose the selection guide of the multi-objective optimization methods for the ergonomic design. The proposed guide enables designers to select an appropriate method for optimizing the human characteristics composed of the engineering characteristics (e.g. users’ height, weight and muscular strength) and the physiological characteristics (e.g. brain wave, pulse-beat and myoelectric signal) in the trade-off relationships.
Design/methodology/approach
This paper focuses on the types of the relationships between engineering or physiological characteristics and their psychological characteristics (e.g. comfort and usability). Using these relationships and the characteristics of the multi-objective optimization methods, this paper classified them and constructed a flow chart for selecting them.
Findings
This paper applied the proposed selection guide to a geometric design of a comfortable seat and confirmed its applicability. The selected multi-objective optimization method optimized the contact area of seat back (engineering characteristic associated with the comfortable fit of the seat backrest) and the blood flow volume (physiological characteristic associated with the numbness in the lower limb) on the basis of each design intent such as a deep-vein thrombosis after long flight.
Originality/value
Because of the lack of the selection guide of the multi-objective optimization methods, an inappropriate method is often applied in industry. This paper proposed the selection guide applied in the ergonomic design having a lot of the multi-objective optimization problem.
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Jonathan S. Greipel, Regina M. Frank, Meike Huber, Ansgar Steland and Robert H. Schmitt
To ensure product quality within a manufacturing process, inspection processes are indispensable. One task of inspection planning is the selection of inspection characteristics…
Abstract
Purpose
To ensure product quality within a manufacturing process, inspection processes are indispensable. One task of inspection planning is the selection of inspection characteristics. For optimization of costs and benefits, key characteristics can be defined by which the product quality can be checked with sufficient accuracy. The manual selection of key characteristics requires substantial planning effort and becomes uneconomic if many product variants prevail. This paper, therefore, aims to show a method for the efficient determination of key characteristics.
Design/methodology/approach
The authors present a novel Algorithm for the Selection of Key Characteristics (ASKC) based on an auto-encoder and a risk analysis. Given historical measurement data and tolerances, the algorithm clusters characteristics with redundant information and selects key characteristics based on a risk assessment. The authors compare ASKC with the algorithm Principal Feature Analysis (PFA) using artificial and historical measurement data.
Findings
The authors find that ASKC delivers superior results than PFA. Findings show that the algorithms enable the cost-efficient selection of key characteristics while maintaining the informative value of the inspection concerning the quality.
Originality/value
This paper fills an identified gap for simplified inspection planning with the method for the efficient selection of key features via ASKC.
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Yongshuai Wang, Md. Abdullah Al Mahbub and Haibiao Zheng
This paper aims to propose a characteristic stabilized finite element method for non-stationary conduction-convection problems.
Abstract
Purpose
This paper aims to propose a characteristic stabilized finite element method for non-stationary conduction-convection problems.
Design/methodology/approach
To avoid difficulty caused by the trilinear term, the authors use the characteristic method to deal with the time derivative term and the advection term. The space discretization adopts the low-order triples (i.e. P1-P1-P1 and P1-P0-P1 triples). As low-order triples do not satisfy inf-sup condition, the authors use the stability technique to overcome this flaw.
Findings
The stability and the convergence analysis shows that the method is stable and has optimal-order error estimates.
Originality/value
Numerical experiments confirm the theoretical analysis and illustrate that the authors’ method is highly effective and reliable, and consumes less CPU time.
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A new algorithm for the inhomogeneous Boltzmann equation in one spatial and velocity dimension, based on the method of characteristics, is presented. Using the analytic solution…
Abstract
A new algorithm for the inhomogeneous Boltzmann equation in one spatial and velocity dimension, based on the method of characteristics, is presented. Using the analytic solution to the Boltzmann equation along its characteristics, the solution to the classical transport problem in semiconducting structures within the relaxation time approximation for the collision integral is obtained iteratively. An n+nn+‐diode is studied numerically and the effects of ballastic electrons on low‐order moments are investigated.
Patrik Jonsson and Stig-Arne Mattsson
The purpose of this paper is to explain the effects of inherent differentiation and system level performance assessment in inventory management. This is done by comparing the…
Abstract
Purpose
The purpose of this paper is to explain the effects of inherent differentiation and system level performance assessment in inventory management. This is done by comparing the performance of two common safety stock methods, by considering the methods’ inherent differentiation and item group-level performance effects.
Design/methodology/approach
Due to the lack of analytical relationships between the two methods, the analysis is based on event-driven simulations. Data are collected from eight different case companies. Findings explain the importance of assessing safety stock performance for groups of items and not for individual items, as is common in academic studies. It explains how the methods’ inherent differentiation and planning environment characteristics affect the relative performances of the two safety stock methods.
Findings
The study explains the importance of assessing performance of safety stock methods on a system-level, rather than on item-level measures. It explains why the demand fill-rate method has a negative impact on the performance for groups of items, while the number-of-days method has a positive impact. The study also explains how the group-level safety stock performance is affected by five demand data characteristics.
Research limitations/implications
The study explains the importance of assessing performance of safety stock methods on a system-level, rather than on item-level measures. It explains why the demand fill-rate method has a negative impact on the performance for groups of items, while the number-of-days method has a positive impact. The study also explains how the group-level safety stock performance is affected by five demand data characteristics.
Practical implications
Understanding the necessity of system level assessment of safety stock performance, how methods inherently differentiate service levels, and how demand characteristics affect methods’ performance can guide the choice of safety stock methods in companies.
Originality/value
No research on the characteristics of the number-of-days safety stock method, any assessment of differentiation characteristics of and comparison with the demand fill-rate method, has been published. The variable “inherent differentiation” is also introduced and defined.
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Xu Kang and Dechang Pi
The purpose of this paper is to detect the occurrence of anomaly and fault in a spacecraft, investigate various tendencies of telemetry parameters and evaluate the operation state…
Abstract
Purpose
The purpose of this paper is to detect the occurrence of anomaly and fault in a spacecraft, investigate various tendencies of telemetry parameters and evaluate the operation state of the spacecraft to monitor the health of the spacecraft.
Design/methodology/approach
This paper proposes a data-driven method (empirical mode decomposition-sample entropy-principal component analysis [EMD-SE-PCA]) for monitoring the health of the spacecraft, where EMD is used to decompose telemetry data and obtain the trend items, SE is utilised to calculate the sample entropies of trend items and extract the characteristic data and squared prediction error and statistic contribution rate are analysed using PCA to monitor the health of the spacecraft.
Findings
Experimental results indicate that the EMD-SE-PCA method could detect characteristic parameters that appear abnormally before the anomaly or fault occurring, could provide an abnormal early warning time before anomaly or fault appearing and summarise the contribution of each parameter more accurately than other fault detection methods.
Practical implications
The proposed EMD-SE-PCA method has high level of accuracy and efficiency. It can be used in monitoring the health of a spacecraft, detecting the anomaly and fault, avoiding them timely and efficiently. Also, the EMD-SE-PCA method could be further applied for monitoring the health of other equipment (e.g. attitude control and orbit control system) in spacecraft and satellites.
Originality/value
The paper provides a data-driven method EMD-SE-PCA to be applied in the field of practical health monitoring, which could discover the occurrence of anomaly or fault timely and efficiently and is very useful for spacecraft health diagnosis.
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This study aims to capture the effective behavior of double-diffusion problem, which arises from the combined heat and mass transfer in porous medium and develop the modified…
Abstract
Purpose
This study aims to capture the effective behavior of double-diffusion problem, which arises from the combined heat and mass transfer in porous medium and develop the modified characteristics finite element method.
Design/methodology/approach
The proposed finite element method deals with the nonlinear term temporal term by modified characteristics method. Then, the authors compute the velocity, pressure, temperature and concentration using the decoupled technique. Finally, to show the efficiency of the method, the authors give some numerical examples.
Findings
From the numerical results, one can see that the method has a good accuracy, which shows that the method can simulate this Darcy–Brinkman problem well.
Originality/value
The originality lies in the fact that the proposed scheme is the first time for solving the Darcy–Brinkman problem, which is a more complicated model, and includes the velocity, pressure, temperature and concentration.
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This study aims to trace methods that help to develop the reflective behaviour that is necessary for identifying and describing learning processes in organisations that focus on…
Abstract
Purpose
This study aims to trace methods that help to develop the reflective behaviour that is necessary for identifying and describing learning processes in organisations that focus on improvement and innovation.
Design/methodology/approach
An extensive literature review results in the characteristics of reflection when reflection is used to trace learning processes in innovation. This results in five characteristics. Literature on research methodology is reviewed in order to find methods that promote this reflective behaviour. These methods are analysed to find out to what extent they contain the characteristics for reflection in innovation processes.
Findings
The literature review leads to five elements that characterise reflective behaviour in innovation processes. It offers a description of several methods that can be used to identify learning processes. The main conclusion is that hardly any method contains all five characteristics for adequate reflective behaviour.
Research limitations/implications
The current study mainly reviewed research methodologies and no other methods that actively promote reflection.
Practical implications
The findings offer concrete guidance for practitioners how to encourage reflective behaviour and innovation processes.
Originality/value
The paper refers to the interest of both research and practice. From the research point of view it presents a variety of methods for analysing learning processes in order to deepen our knowledge with respect to these processes. From the practice point of view, it offers concrete methods that enable participants to develop reflective skills that help them to become more knowledge productive.
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The purpose of this paper is to advocate for a clearer and less fragmentary use of qualitative research in the increasingly interdisciplinary research setting of information…
Abstract
Purpose
The purpose of this paper is to advocate for a clearer and less fragmentary use of qualitative research in the increasingly interdisciplinary research setting of information science.
Design/methodology/approach
The paper performs a textual analysis of more than 500 peer‐reviewed articles to assess information science's involvement with qualitative research. The paper undertakes historical criticism to trace qualitative research in the reviews of information science for the last three decades.
Findings
Authors are unclear and lax in their uses of basic research terms. Authors do not account for qualitative research's characteristics, methods, and contributions to information science's bodies of knowledge. Only 4.3 percent of published articles mention their contributions to information science's literature whereas 5.6 percent mention qualitative method(s) in their abstracts. Publications do not show (intra‐)collaboration between areas of information science. Information science's contributions to the theoretical discussions of the wider scientific community are lacking.
Originality/value
The paper discusses afresh information science's qualitative research. The paper suggests a tighter and long‐term investment of information science in qualitative research and the formation of the information science's own theorists and theory‐illumined practitioners. The paper puts forth some practical recommendations.
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Marta Widłak and Emilia Tomczyk
The aim of this paper is to present estimation results of hedonic price models as well as housing price indices for the Warsaw secondary market.
Abstract
Purpose
The aim of this paper is to present estimation results of hedonic price models as well as housing price indices for the Warsaw secondary market.
Design/methodology/approach
Three direct methods of constructing a hedonic price index and four indices that allow for quality adjustment are presented. The paper also discusses theoretical issues related to the estimation and interpretation of hedonic models.
Findings
It is shown that the imputation and the time dummy variable indices are subject to less variation than the characteristic price index. It is also shown that in comparison to the mean and the median, hedonic indices are less variable, which can be interpreted as partial control for quality changes in dwellings sold.
Practical implications
As this research project represents one of the first attempts of hedonic modelling applied to the Polish housing market, its results may be employed by appraisers to gain insight into behaviour of the Warsaw housing market. Practical implications focus on reliable measurement of house price dynamics in Poland. This paper supplies an appropriate methodology for addressing this question and offers empirical solutions.
Originality/value
Employment of hedonic models for construction of quality‐adjusted housing price indices has not yet been explored in Poland. The theoretical and practical aspects of hedonic indices presented in the paper open promising directions for the development of Polish statistics of real estate prices.