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Byeong U. Park Enno Mammen Young K. Lee Eun Ryung Lee 《Revue internationale de statistique》2015,83(1):36-64
Varying coefficient regression models are known to be very useful tools for analysing the relation between a response and a group of covariates. Their structure and interpretability are similar to those for the traditional linear regression model, but they are more flexible because of the infinite dimensionality of the corresponding parameter spaces. The aims of this paper are to give an overview on the existing methodological and theoretical developments for varying coefficient models and to discuss their extensions with some new developments. The new developments enable us to use different amount of smoothing for estimating different component functions in the models. They are for a flexible form of varying coefficient models that requires smoothing across different covariates' spaces and are based on the smooth backfitting technique that is admitted as a powerful technique for fitting structural regression models and is also known to free us from the curse of dimensionality. 相似文献
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Our study of professional services firms clearly revealed that firms change over the course of their life cycles. During the first three stages, diversification in sales, the differentiation in labor force, and the level of labor productivity increase. In the last stage, diversification in sales, the differentiation in labor force, and the level of labor productivity decrease. Development effects can be treated as interdependent. Our findings show that the effects of growth can be predicted to a certain extent. In efforts towards development, these predictions are important to business strategy, as well as to consultation with and education of SME entrepreneurs. 相似文献
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Jörg-Volker Schrader Walter KrÄmer Paulgeorg Juhl Walter A. S. Koch Harmen Lehment Kurt W. Rothschild Peter Nunnenkamp Paulgeorg Juhl H. Peter Gray Enno Langfeldt Ulrich Fehl 《Review of World Economics》1982,118(4):779-803
Ohne Zusammenfassung 相似文献
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To assess the attainable greenhouse gas (GHG) mitigation potential from crop production in China's most important grain production region, the North China Plain (NCP), single farm environmental and economic performances of 65 winter wheat–summer maize (WW–SM) producing households were determined. The results revealed a huge heterogeneity among farms, with up to five times higher environmental impact of worst compared to best performing farms. Astonishingly no trade-off between productivity and sustainability could be identified in the region, with high-yield farms emitting no different amounts of GHGs per hectare compared to low-yield farms. Building on cluster analysis, with farms grouped according to their economic and environmental performance into ‘poor’, ‘fair' and ‘good’ producers, the regional GHG mitigation potential was estimated. Under the scenario assumption that all grain in the NCP is produced under ‘good’ production conditions, 21% and 7% of GHG could be mitigated in wheat and maize production, respectively. The study shows that in the NCP, exemplary for China's rapidly developing agricultural sector, the crop management skills of a substantial share of farmers could obviously not keep pace with the massive input intensification. Among others, farmer–farmer trainings are recommended to close the gap in crop production performance among producers. 相似文献
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Enno Masurel Peter Nijkamp Gabriella Vindigni 《Entrepreneurship & Regional Development》2013,25(1):77-86
This paper aims to examine the performance conditions of ethnic (migrant) entrepreneurs in a modern economy. After a broad overview of key issues, an analytical tool from marketing theory is proposed, based on the five Ps (Product, Price, Place, Personnel and Promotion). Next, an empirical application is presented, in which results from an in-depth interview study on Moroccan entrepreneurs in Amsterdam are discussed. Given the linguistic and qualitative information in our data base, two recently developed pattern recognition methods for categorized information, namely Apriori and rough set methods, are deployed in order to derive meaningful association and classification rules that are helpful to identify conditional success or performance rules. 相似文献
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The relation between planning behaviour and performance is analyzed for a large number of small real estate firms in the Netherlands. A firm's planning behaviour appears to be influenced by the way it perceives its environment (in terms of complexity and dynamics) as well as its own characteristics (size, age and activities). The explanation of performance is dominated by a firm's size and the nature of its activities. Hardly and effect of planning on a firm's performance is found, though it appears that in an environment perceived as highly dynamic, planning is merely counter-productive.The authors wish to thank Jan Eppink and Ingrid van Rijn, and are especially grateful to Roy Thurik and two anonymous referees for valuable comments on earlier drafts. It goes without saying that errors and omissions remain the full responsibility of the authors. 相似文献
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We consider a semiparametric distributed lag model in which the “news impact curve” m is nonparametric but the response is dynamic through some linear filters. A special case of this is a nonparametric regression with serially correlated errors. We propose an estimator of the news impact curve based on a dynamic transformation that produces white noise errors. This yields an estimating equation for m that is a type two linear integral equation. We investigate both the stationary case and the case where the error has a unit root. In the stationary case we establish the pointwise asymptotic normality. In the special case of a nonparametric regression subject to time series errors our estimator achieves efficiency improvements over the usual estimators, see Xiao et al. [2003. More efficient local polynomial estimation in nonparametric regression with autocorrelated errors. Journal of the American Statistical Association 98, 980–992]. In the unit root case our procedure is consistent and asymptotically normal unlike the standard regression smoother. We also present the distribution theory for the parameter estimates, which is nonstandard in the unit root case. We also investigate its finite sample performance through simulation experiments. 相似文献
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Enno Masurel 《Business Strategy and the Environment》2007,16(3):190-201
Why do SMEs invest in environmental measures? From the literature we know that most SMEs are rather slow in adopting these sustainable measures, but then the following question arises: why are other SMEs fast in this respect? From our research, it becomes clear that improving the working conditions is the most important reason why these fast‐going SMEs invest in environmental measures, as this probably improves their employees' motivation and performance. This explanation connects ‘planet’ and ‘people’ with each other, and does not exclude ‘profit’, which completes the traditional sustainability circle. Copyright © 2006 John Wiley & Sons, Ltd and ERP Environment. 相似文献
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Fengler Matthias R.; Hardle Wolfgang K.; Mammen Enno 《The Journal of Financial Econometrics》2007,5(2):189-218
We propose a semiparametric factor model, which approximatesthe implied volatility surface (IVS) in a finite dimensionalfunction space. Unlike standard principal component approachestypically used to reduce complexity, our approach is tailoredto the degenerated design of IVS data. In particular, we onlyfit in the local neighborhood of the design points by exploitingthe expiry effect present in option data. Using DAX index optiondata, we estimate the nonparametric components and a low-dimensionaltime series of latent factors. The modeling approach is completedby studying vector autoregressive models fitted to the latentfactors. 相似文献