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1.
The M4 competition is the continuation of three previous competitions started more than 45 years ago whose purpose was to learn how to improve forecasting accuracy, and how such learning can be applied to advance the theory and practice of forecasting. The purpose of M4 was to replicate the results of the previous ones and extend them into three directions: First significantly increase the number of series, second include Machine Learning (ML) forecasting methods, and third evaluate both point forecasts and prediction intervals. The five major findings of the M4 Competitions are: 1. Out Of the 17 most accurate methods, 12 were “combinations” of mostly statistical approaches. 2. The biggest surprise was a “hybrid” approach that utilized both statistical and ML features. This method’s average sMAPE was close to 10% more accurate than the combination benchmark used to compare the submitted methods. 3. The second most accurate method was a combination of seven statistical methods and one ML one, with the weights for the averaging being calculated by a ML algorithm that was trained to minimize the forecasting. 4. The two most accurate methods also achieved an amazing success in specifying the 95% prediction intervals correctly. 5. The six pure ML methods performed poorly, with none of them being more accurate than the combination benchmark and only one being more accurate than Naïve2. This paper presents some initial results of M4, its major findings and a logical conclusion. Finally, it outlines what the authors consider to be the way forward for the field of forecasting.  相似文献   
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Following recent advances in the non‐parametric realized volatility approach, we separately measure the discontinuous jump part of the quadratic variation process for individual stocks and incorporate it into heterogeneous autoregressive volatility models. We analyse the distributional properties of the jump measures vis‐à‐vis the corresponding realized volatility ones, and compare them to those of aggregate US market index series. We also demonstrate important gains in the forecasting accuracy of high‐frequency volatility models.  相似文献   
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This study assesses the relative performance of Greek equity funds employing a non-parametric method, namely Data Envelopment Analysis (DEA). Specifically, we evaluate the funds’ total productivity change using the DEA-based Malmquist Index. Our results reveal significant losses in funds’ productivity for the period of 2003–2009, which calls for the attention of domestic policy makers and market regulators. Significant implications for the investors’ fund selection process arise from our analysis since we are able to identify potential sources of operational inefficiencies. Employing a panel logit model we document a significant negative relationship between the probability of being efficient and funds’ size, a finding which may be related to the microstructure of the domestic stock market. Furthermore, we provide evidence against the notion of funds’ mean-variance efficiency.  相似文献   
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E-procurement in the Greek food and drink industry: Drivers and impediments   总被引:1,自引:1,他引:0  
Most empirical research on e-procurement has focused on large economies and technology-related industries, paying little attention to smaller economies and traditional industries. This paper addresses this gap by presenting a study on the state and development of e-procurement in the Greek food and drink industry, based on four case studies with some of the largest organisations in the industry. This study indicates that the uptake of e-procurement has been slow and reveals some important impediments, such as the uncertainty of the technology and its benefits, the lack of infrastructure and skills and the traditional nature of the industry. These results led to a series of findings, propositions for further investigation. The drivers and impediments to e-procurement have been classified into four different levels: global, country, industry and firm. Each of these levels requires a different approach to dealing with it, having implications for practitioners and policymakers.  相似文献   
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Motivated by financial liberalization investors seek for new investment opportunities through international portfolio diversification. To this end we explore any asymmetric causal relationship between developed European stock markets (Germany, France and UK) and emerging Baltic markets namely; Estonia, Latvia and Lithuania. Our analysis focuses on the period before and after countries’ EU accession and pre- and post the global financial crisis. For this purpose, both the standard parametric test for causality and a novel nonparametric test for causality-in-quantiles are employed. The results of both the parametric and nonparametric Granger causality test support a causal relationship in mean that runs from all of the major markets to the Baltic markets across both samples. The results imply the existence of significant nonlinear return and volatility spillover from European markets to Baltic markets. Policy implications for international investors are also discussed.  相似文献   
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Although the use of planned events for achieving community development has received academic attention from different disciplines, the findings of these literatures are not systematically used towards developing a common understanding aimed at fostering their social utility. The challenge then is to study from an integrated interdisciplinary perspective how the social value of events can be fostered and leveraged for community development. In addressing this challenge, the purpose of this conceptual paper is to shed light on the multi-layered processes that foster the social utility of events. To this end, the theoretical tenets of social leverage, event dramaturgy and social capital are employed and integrated. On this basis, a conceptual framework linking event processes and outcomes is proposed aimed to guide future interdisciplinary research towards strategically incorporating events in community development. This line of research can eventually help create synergies between different event genres and implement joint social leveraging strategies, hence, fostering and magnifying their overall social utility for host communities.  相似文献   
10.
This study examines the impacts of the global economic crisis on Cyprus tourism and the pertinent policy responses. A qualitative approach was adopted by conducting eight semi‐structured interviews with tourism authorities and suppliers/professionals. Findings indicated the main impacts of the crisis on Cypriot tourism: lack of competitiveness, decreased visitation/revenues, inadequate quality and escalated pricing. Furthermore, findings identify three types of policy measures: (i) immediate response measures; (ii) foreign investment in tourism; and (iii) diversification of the tourism product and quality improvement. The study highlights the need for Cyprus to develop a comprehensive tourism planning framework. It is suggested that crisis plans of small island states should be developed upon a holistic framework that leverages their destination capitals. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
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