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Article

Martin Zwick and Michael S. Johnson

Reconstructability analysis (RA) is a method for detecting and analyzing the structure of multivariate categorical data. While Jones and his colleagues extended the…

Abstract

Reconstructability analysis (RA) is a method for detecting and analyzing the structure of multivariate categorical data. While Jones and his colleagues extended the original variable‐based formulation of RA to encompass models defined in terms of system states, their focus was the analysis and approximation of real‐valued functions. In this paper, we separate two ideas that Jones had merged together: the “g to k” transformation and state‐based modeling. We relate the idea of state‐based modeling to established variable‐based RA concepts and methods, including structure lattices, search strategies, metrics of model quality, and the statistical evaluation of model fit for analyses based on sample data. We also discuss the interpretation of state‐based modeling results for both neutral and directed systems, and address the practical question of how state‐based approaches can be used in conjunction with established variable‐based methods.

Details

Kybernetes, vol. 33 no. 5/6
Type: Research Article
ISSN: 0368-492X

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Article

Edilson M. Assis, Ernesto P. Borges, Silvio A.B. Vieira de Melo and Leizer Schnitman

The purpose of this paper is to compare four life data models, namely the exponential and the Weibull models, and their corresponding generalized versions, q-exponential…

Abstract

Purpose

The purpose of this paper is to compare four life data models, namely the exponential and the Weibull models, and their corresponding generalized versions, q-exponential and q-Weibull models, by means of one practical application.

Design/methodology/approach

Application of the models to a practical example (a welding station), with estimation of parameters by the use of the least squares method, and the Akaike Information Criterion (AIC).

Findings

The data of the example considered in this paper is divided into three regimes, decreasing, constant and increasing failure rate, and the q-Weibull model describes the bathtub curve displayed by the data with a single set of parameters.

Practical implications

The simplicity and flexibility of the q-Weibull model may be very useful for practitioners of reliability analysis, and its benefits surpasses the inconvenience of the additional parameter, as AIC shows.

Originality/value

The q-Weibull model is compared in detail with other three models, through the analysis of one example that clearly exhibits a bathtub curve, and it is shown that it can describe the whole time range with a single set of parameters.

Details

International Journal of Quality & Reliability Management, vol. 32 no. 2
Type: Research Article
ISSN: 0265-671X

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Article

Ray Perry

Automating warehouse operations can be a very alluring proposition. However, it is vital that a decision to progress with such substantial investment is taken only after…

Abstract

Automating warehouse operations can be a very alluring proposition. However, it is vital that a decision to progress with such substantial investment is taken only after the deliverable benefits are thoroughly understood. This is especially important when the business environment is changing rapidly. Describes the approach taken by B&Q to decide on the appropriate level of automation; explains how, through a process of establishing good performance through manual processes, it has created a sound base against which it can evaluate automation, and how its new supply chain strategy has exposed further opportunities to improve business performance. Also describes how B&Q Distribution has renewed its focus on serving the customer (the B&Q retail store), and how this experience has affected the automation project. Finally, covers B&Q’s approach to supplier selection.

Details

Logistics Information Management, vol. 9 no. 2
Type: Research Article
ISSN: 0957-6053

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Article

Martin Zwick

Fourier methods used in two‐ and three‐dimensional image reconstruction can be used also in reconstructability analysis (RA). These methods maximize a variance‐type…

Abstract

Fourier methods used in two‐ and three‐dimensional image reconstruction can be used also in reconstructability analysis (RA). These methods maximize a variance‐type measure instead of information‐theoretic uncertainty, but the two measures are roughly collinear and the Fourier approach yields results close to that of standard RA. The Fourier method, however, does not require iterative calculations for models with loops. Moreover, the error in Fourier RA models can be assessed without actually generating the full probability distributions of the models; calculations scale with the size of the data rather than the state space. State‐based modeling using the Fourier approach is also readily implemented. Fourier methods may thus enhance the power of RA for data analysis and data mining.

Details

Kybernetes, vol. 33 no. 5/6
Type: Research Article
ISSN: 0368-492X

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Article

S. Spitans and A. Jakovičs

The purpose of this paper is to compare k‐ω shear‐stress transport (SST) and large eddy simulation (LES) turbulence model application effect on numerical computation of…

Abstract

Purpose

The purpose of this paper is to compare k‐ω shear‐stress transport (SST) and large eddy simulation (LES) turbulence model application effect on numerical computation of flow pattern and heat exchange characteristics through the neutron beam window region for European spallation source setup model.

Design/methodology/approach

Transient hydrodynamic and thermal calculations with appropriate heat sources are performed using both turbulence models and typical discrepancies in flow and thermal patterns are discussed, as well as, simulation results are qualitatively compared with experimental data for heat transfer coefficient distribution α at the window surface.

Findings

Contribution of greater k‐energy field obtained with LES calculation leads to prediction of more intensive heat transfer in comparison to k‐ω SST.

Originality/value

The paper illustrates discrepancies of thermal patterns caused by application of k‐ω SST and LES turbulent models.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 30 no. 5
Type: Research Article
ISSN: 0332-1649

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Article

Y.K. Chan, P. Gaffney, K. Neailey and W.H. Ip

In today’s public transport market where competition is keener than ever, railway operators are in desperate need of a customised total quality management approach to…

Abstract

In today’s public transport market where competition is keener than ever, railway operators are in desperate need of a customised total quality management approach to enhance performance and outcompete their counterparts. This paper outlines the work related to the establishment and implementation of such a total management approach, an integrated management system evolved from the ISO 9000‐based quality management system, in the Mass Transit Railway Corporation (MTR Corporation), Hong Kong, and how this system serves to enhance the corporation’s competitiveness by successfully addressing its rapidly changing needs.

Details

The TQM Magazine, vol. 10 no. 6
Type: Research Article
ISSN: 0954-478X

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Article

Helen Xiaohui Bao, Helen Hui Huang, Yu-Lieh Huang and Pin-te Lin

– The purpose of this paper is to investigate the volatility clustering in the return of land markets through both theoretical and empirical approaches.

Abstract

Purpose

The purpose of this paper is to investigate the volatility clustering in the return of land markets through both theoretical and empirical approaches.

Design/methodology/approach

Using extensive monthly panel data at the provincial level from 1986 to 2013, the authors identify the existence of time-correlated and time-varying returns in Canadian land markets.

Findings

Consistent with the proposed theory, volatility clustering in land markets tends to be observed in more populated areas.

Originality/value

The result has significant implications for portfolio management, economic theory and government policy by revealing the systematic pattern of volatility clustering in land markets.

Details

Property Management, vol. 32 no. 5
Type: Research Article
ISSN: 0263-7472

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Book part

Mariangela Bonasia and Rosaria Rita Canale

The aim of this chapter is to show the limits of the European policy model and to support the existence, through straightforward empirical analysis, of an inverse…

Abstract

The aim of this chapter is to show the limits of the European policy model and to support the existence, through straightforward empirical analysis, of an inverse relationship both in the short run and in the long run between trust in institutions and unemployment. The empirical methodology relies on dynamic panel data techniques allowing measuring in a single equation both the long-run relationship and the short-run speed of adjustment among variables. This connection appears to be valid both in the Eurozone considered as a whole and in particular in peripheral countries, where the macroeconomic dynamics have been, under this respect, much more divergent from the average. This outcome allows proofing that to consolidate the European process of integration in the long run, institutions should have as main objective not only inflation but especially unemployment.

Details

Economic Imbalances and Institutional Changes to the Euro and the European Union
Type: Book
ISBN: 978-1-78714-510-8

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Book part

David P. Brown and Jens Carsten Jackwerth

The pricing kernel puzzle of Jackwerth (2000) concerns the fact that the empirical pricing kernel implied in S&P 500 index options and index returns is not monotonically…

Abstract

The pricing kernel puzzle of Jackwerth (2000) concerns the fact that the empirical pricing kernel implied in S&P 500 index options and index returns is not monotonically decreasing in wealth as standard economic theory would suggest. Thus, those options are currently priced in a way such that any risk-averse investor would increase his/her utility by trading in them. We provide a representative agent model where volatility is a function of a second momentum state variable. This model is capable of generating the empirical patterns in the pricing kernel, albeit only for parameter constellations that are not typically observed in the real world.

Details

Derivative Securities Pricing and Modelling
Type: Book
ISBN: 978-1-78052-616-4

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Article

Nouara Ouazraoui and Rachid Nait-Said

The purpose of this paper is to validate a fuzzy risk graph model through a case study results carried out on a safety instrumented system (SIS).

Abstract

Purpose

The purpose of this paper is to validate a fuzzy risk graph model through a case study results carried out on a safety instrumented system (SIS).

Design/methodology/approach

The proposed model is based on an inference fuzzy system and deals with uncertainty data used as inputs of the conventional risk graph method. The coherence and redundancy of the developed fuzzy rules base are first verified in the case study. A new fuzzy model is suggested for a multi-criteria characterization of the avoidance possibility parameter. The fuzzy safety integrity level (SIL) is determined for two potential accident scenarios.

Findings

The applicability of the proposed fuzzy model on SIS shows the importance and pertinence of the proposed fuzzy model as decision-making tools in preventing industrial hazards while taking into consideration uncertain aspects of the data used on the conventional risk graph method. The obtained results show that the use of continuous fuzzy scales solves the problem of interpreting results and provides a more flexible structure to combine risk graph parameters. Therefore, a decision is taken on the basis of precise integrity level values and protective actions in the real world are suggested.

Originality/value

Fuzzy logic-based safety integrity assessment allows assessment of the SIL in a more realistic way by using the notion of the linguistic variable for representing information that is qualitative and imprecise and, therefore, ensures better decision making on risk prevention.

Details

International Journal of Quality & Reliability Management, vol. 36 no. 10
Type: Research Article
ISSN: 0265-671X

Keywords

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