378 research outputs found
Customer enquiry management and product customization: an empirical multi-case study analysis in the Italian capital goods sector
No full textPurpose – The customer enquiry management (CEM) process is of strategic importance in engineer-to-order contexts but existing literature does not adequately describe how firms support delivery date setting and order acceptance decisions in practice. This paper seeks to explore how and why the CEM process varies between companies in the capital goods sector, thereby taking a contingency theory approach. Design/methodology/approach – Multi-case study research involving 18 Italian capital goods manufacturers in four industrial sectors. Face-to-face interviews with senior representatives have been conducted. Companies have been grouped into five clusters, based on similarities in their CEM decision-making modes, to aid analysis. Findings – Three contingency factors were found to be particularly relevant in determining CEM modes: degree of product customization, flexibility of the production system, and uncertainty of the context. These factors affect the choice of specific CEM decision-making modes. However, a high level of cross-functional coordination and formalization of the process were found to constitute best practices whatever the contingency factors. Research limitations/implications – The research focuses on companies belonging to the Italian capital goods sector – findings may differ in other countries and sectors. Practical implications – The results indicate that all firms, including small and medium-sized companies, should implement high levels of cross-functional coordination and formalization in their CEM practices, in order to improve their performance. For other aspects of the CEM process, including supplier and subcontractor monitoring, the company context will indicate whether these aspects are required, according to a need of matching the approach to CEM with specific sets of contingency factors. Originality/value – This paper provides a rare insight into the CEM processes found in practice
Efficiency of Exciton and Charge Carrier Photogeneration in a Semiconducting Polymer
No full textEuan Hendry, Juleon M. Schins, L. P. Candeias, L. D. A. Siebbeles, and Mischa Bonn, Physical Review Letters, Vol. 92, article 196601 (2004). "Copyright © 2004 by the American Physical Society."We determine the efficiencies for the formation of excitons and charge carriers following ultrafast photoexcitation of a semiconducting polymer (MEH-PPV). The simultaneous, quantitative determination of exciton and charge photoyields is achieved through subpicosecond studies of both the real and the imaginary components of the complex conductivity over a wide frequency range. Predominantly excitons, with near-unity quantum efficiency, are generated on excitation, while only a very small fraction (<10-2) of free charges are initially excited, consistent with rapid (∼100 fs) hot exciton dissociation. These initial charges are very short lived, decaying on subpicosecond time scales
Ultrafast charge generation in a semiconducting polymer studied with THz emission spectroscopy
No full textEuan Hendry, Mattijs Koeberg, Juleon M. Schins, L. D. A. Siebbeles, and Mischa Bonn, Physical Review B, Vol. 70, article 033202 (2004). "Copyright © 2004 by the American Physical Society."We study the ultrafast charge generation in a semiconducting polymer (MEH-PPV) by measuring the radiated THz field after photoexciting the biased polymer with a femtosecond visible pulse. The subpicosecond temporal characteristics of the emitted wave reflects the ultrafast photoconductivity dynamics and sets an upper limit for charge generation of 200 fs following photoexcitation, and reveals the dispersive nature of charge transport in MEH-PPV. A comparison of the fields radiated from MEH-PPV and the well-characterized model semiconductor system (GaAs) allows for an accurate estimate of the quantum efficiency for charge generation in the polymer, found to be less than 1% . Both observations are consistent with ultrafast charge generation in semiconducting polymers through hot exciton dissociation
Understanding economic forecasts
No full textNine articles, originally presented at the Annual Festival of Science at the University of Sheffield in September 1999, explain new developments in economic forecasting. Papers examine how economists forecast (David F. Hendry); economic modeling for fun and profit (Paul Turner); making sense of published economic forecasts (Diane Coyle); forecast uncertainty in economic modeling (Neil R. Ericsson); evaluation of forecasts (Clive W. J. Granger); forecasting and the UK business cycle (Denise R. Osborn, Marianne Sensier, and Paul W. Simpson); modeling and forecasting at the Bank of England (Neal Hatch); forecasting the world economy (Ray Barrell); and the costs of forecast errors (Terence Burns). Hendry is Professor of Economics at Nuffield College, Oxford University. Ericsson is a staff economist at the Division of International Finance, Federal Reserve Board. Author and subject indexes
Understanding economic forecasts
No full textNine articles, originally presented at the Annual Festival of Science at the University of Sheffield in September 1999, explain new developments in economic forecasting. Papers examine how economists forecast (David F. Hendry); economic modeling for fun and profit (Paul Turner); making sense of published economic forecasts (Diane Coyle); forecast uncertainty in economic modeling (Neil R. Ericsson); evaluation of forecasts (Clive W. J. Granger); forecasting and the UK business cycle (Denise R. Osborn, Marianne Sensier, and Paul W. Simpson); modeling and forecasting at the Bank of England (Neal Hatch); forecasting the world economy (Ray Barrell); and the costs of forecast errors (Terence Burns). Hendry is Professor of Economics at Nuffield College, Oxford University. Ericsson is a staff economist at the Division of International Finance, Federal Reserve Board. Author and subject indexes
Customer enquiry management in global supply chains : a comparative multi-case study analysis
No full textThe Customer Enquiry Management (CEM) process is of strategic importance to non-Make-To-Stock companies but few empirical studies have explored the CEM practices adopted by firms in practice. A study on the Italian capital goods sector by Zorzini, Hendry, Stevenson, and Pozzetti (2008) provides the most comprehensive contingency-based framework to date. This paper builds on Zorzini et al. (2008) by conducting multi-case study research with seven global capital goods companies managing CEM in the UK. The evidence suggests that both high levels of coordination and formalization of the CEM process are linked to improved performance. In particular, cross-functional coordination and formalization impact jointly on the performance of companies characterized by a large-sized control problem. Two moderating factors are also identified: the proportion of slightly/highly customized orders and the availability of integrated information systems. Analysis of the impact of supply chain coordination and other globalization factors on CEM shows that CEM practices are: directly influenced by the complexity of the supply chain configuration; and, indirectly influenced by the types of relationships with supply chain partners. Two sources of complexity that result from operating in a global context are also identified: coordinating the activities of sales structures distributed around the world; and, managing global customers with different languages and cultures. In terms of managerial implications, the results indicate that coordination with partners along the supply chain is needed at the customer enquiry stage and constraints linked to global customers should be considered when structuring CEM
Interchain effects in the ultrafast photophysics of a semiconducting polymer: THz time-domain spectroscopy of thin films and isolated chains in solution
No full textEuan Hendry, Mattijs Koeberg, Juleon M. Schins, H. K. Nienhuys, V. Sundström, L. D. A. Siebbeles, and Mischa Bonn, Physical Review B, Vol. 71, article 125201 (2005). Copyright © 2005 by the American Physical Society.We compare the generation and decay dynamics of charges and excitons in a model polymer semiconductor (MEH-PPV) in solution and drop-cast thin films, by recording the sub-ps transient complex conductivity using THz time-domain spectroscopy. The results show that the quantum efficiency of charge generation is two orders of magnitude smaller in solution (~10–5) than in the solid film (~10–3). The proximity of neighboring chains in the films apparently facilitates (hot) exciton dissociation, presumably by allowing the electron and hole to separate on different polymer strands. For both samples, photoexcitation leads to the predominant formation of bound charge pairs (excitons) that can be detected through their polarizability. Surprisingly, the polarizability per absorbed photon is a factor of 3 larger in solution than in the film, suggesting that interchain interactions in the film do not result in a substantial delocalization of the exciton wave function
In-plane failure of brickwork
No full textThis thesis presents the results of an experimental investigation into the strength of brickwork under biaxial tension-compression. Since there is insufficient experimental evidence available on the strength of brickwork under biaxial stress to explain the behaviour of brick masonry walls under in-plane loads, experiments were carried out on one-sixth scale model brickwork panels under uniform stress conditions. An idealized failure surface is suggested based on experimental results, and the effect of shear bond strength and tensile bond strength on the results is discussed. An iterative plane stress finite element computer programme incorporating the above information is used to simulate the in-plane behaviour of brickwork. Brickwork is treated as an elastic, isotropic material with limited capacity when stressed in a state of biaxial tension-compression. The model reproduces the non-linear behaviour of masonry produced by progressive cracking. Shear wall tests have been used to test the validity of the analytical model. Sensitivity analysis of the elastic constants used in the model are performed to illustrate their influence on the calculated stresses. The influence of the stress distribution on shear wall behaviour, and the derivation of a failure criterion for local failure in masonry shear walls, are described. This criterion, in terms of the vertical stress and shear stress at a point, has been derived for particular values of horizontal stress from the three dimensional surface mentioned above. The effect of the shape of the specimen, testing technique, and boundary conditions on the shear strength of masonry panels is discussed
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Forecasting economic time series
No full textAnalyzes the models, procedures, and measures of economic forecasting with a view to improving forecasting practices. This volume sets the scene by focusing on forecasting when the underlying process can be described by a stationary representation. A companion volume, Zeuthen Lectures on Economic Forecasting will discuss forecasting in the presence of deterministic nonstationarities. Provides an introduction to forecasting. Discusses first principles; forecasting in univariate processes; Monte Carlo simulation techniques; forecasting in cointegrated systems; forecasting with large-scale macroeconometric models; the value of intercept corrections; forecasting using leading indicators; combining forecasts; multistep estimation; the value of imposing parsimony; and testing forecast accuracy. Sets out recommendations for forecasting practice. Clements is Research Fellow in Economics at the University of Warwick. Hendry is Leverhulme Personal Research Professor of Economics and Fellow of Nuffield College, Oxford University. Author and subject indexes
Encompassing
No full textWith the kind permission of the Editors of the Oxford Bulletin, this Special Issue onEncompassing is a volume in honour of Grayham E. Mizon, to celebrate his majorcontributions to econometrics, and in particular, to the development of the theory ofencompassing and testing non-nested hypotheses. Grayham’s publications on encom-passing by himself, and with various co-authors (including most contributors to thisSpecial Issue), have been cited more than 800 times, reflecting its widespread useacross a diverse range of empirical and theoretical studies.Grayham has advanced numerous other areas in econometrics, including modelselection and progressive research strategies, panel data and time-series analyses,simulation and Monte Carlo methods, forecast evaluation and economic policy anal-ysis, and exogeneity, as well as encompassing. In addition to the formulation andimplementation of new estimators and test statistics, he has contributed to the sub-stantive application of new econometric tools, developing empirical models andpolicy analyses for both developed and transition economies, investigating consump-tion, employment and output, wage and price inflation, and relative prices. A partialbibliography is provided below.Grayham was also a prolific ‘producer’ of doctoral students – several of whomhave contributed to this Special Issue – as well as a constructive referee and editor,both for specific projects and in general for the highly successful Advanced Texts inEconometrics, which he overviewed with Clive W.J. Granger on behalf of OxfordUniversity Press.We are delighted to have been able to collect together a set of papers whichfurther advance the coverage of encompassing, by investigating the principles ofencompassing; encompassing as a key part of a general empirical methodology;its role in both automatic and human-driven model selection; hypothesis testingfor linear and nonlinear, nested and non-nested, parametric and non-parametricmodels; as well as simulation, forecast, cross-data vintage, and Bayesianencompassing.Until he reads this Foreword, Grayham will have been unaware of this purposeof our Special Issue, despite being the main Guest Editor, and co-author of two ofthe papers. We are grateful to all the contributors for sustaining our secret, and hopeit is a pleasant surprise for Grayham. Most authors and co-authors have been able to offer their own felicitations toGrayham in another paper – one which was not written with him – except for ChiaraMonfardini, who therefore joins the two other Guest Editors in congratulating Gray-ham on a truly fecund career, and wishing him continuing success in unravelling thetheory and practice of econometrics.-- Foreword, David F. Hendry, Massimiliano Marcellino and Chiara Monfardini
-- Guest Editors’ Introduction to Special Issue on Encompassing, David F. Hendry, Massimiliano Marcellino and Grayham E. Mizon
-- Encompassing: Concepts and Implementation, Christophe Bontemps and Grayham E. Mizon
-- Encompassing Procedures, Christophe Bontemps, Jean-Pierre Florens and Jean-François Richard
-- Simulation Encompassing: Testing Non-nested Hypotheses, Maozu Lu, Grayham E. Mizon and Chiara Monfardini
-- Log Income vs. Linear Income: An Application of the Encompassing Principle, Luigi Ermini and David F. Hendry
-- Linear vs. Log-linear Unit-Root Specification: An Application of Mis-specification Encompassing, Aris Spanos, David F. Hendry and J. James Reade
-- Cross-data-vintage Encompassing (pages 849–865) Steve Cook
-- Model Selection for Nested and Overlapping Nonlinear, Dynamic and Possibly Mis-specified Models, Massimiliano Marcellino and Barbara Rossi
-- The Fragility of Sensitivity Analysis: An Encompassing Perspective, Neil R. Ericsson
-- Encompassing and Automatic Model Selection, Jurgen A. Doornik
-- An Omnibus Test for Univariate and Multivariate Normality, Jurgen A. Doornik and Henrik Hanse
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