GEM research: achievements and challenges

This article analyzes the content and evolution of research based on the Global Entrepreneurship Monitor (GEM) project. We conducted a rigorous search of articles published in journals within the Thomson Reuters’ Social Sciences Citation Index^® through an exploratory analysis focused on articles using GEM data. The main findings of this study reveal that the institutional approach is the most commonly used conceptual framework. Also, although there are still few academic publications using GEM data, the number of articles is increasing, as are opportunities for future research.     

Ethnic patterns of returns to education in Bulgaria

It is widely accepted that disparities in education contribute to the poor labour market outcomes experienced by ethnic minority groups and consequently to their poverty. In this article, I analyse differential educational benefits in Bulgaria and compare returns to education for the Roma minority with the majority population and the Turkish minority. I show that both ethnic minority groups have lower education levels and employment rates than the majority population and that they also have lower returns to education. This result could be related to minorities' lower education quality as well as to discrimination in the labour market. Integration policies should thus aim to improve employability and labour market competence of vulnerable groups starting from school.     

On Some Characteristics of Gaussian Covariance Functions

The concepts of isotropy/anisotropy and separability/non‐separability of a covariance function are strictly related. If a covariance function is separable, it cannot be isotropic or geometrically anisotropic, except for the Gaussian covariance function, which is the only model both separable and isotropic. In this paper, some interesting results concerning the Gaussian covariance model and its properties related to isotropy and separability are given, and moreover, some examples are provided. Finally, a discussion on asymmetric models, with Gaussian marginals, is furnished and the strictly positive definiteness condition is discussed.     

Lean Implementation in Small and Medium‐Sized Enterprises in Less Developed Countries: Some Empirical Evidences From North Africa

The purpose of this paper is to provide an exploration and analysis of lean implementation in small and medium‐sized enterprises (SMEs) in less developed countries. Therefore, exploratory empirical evidences were collected from a survey study among a sample of 84 SMEs in North Africa. Moreover, statistical tests were conducted to assess the overall picture of lean among SMEs in this region. Although SMEs have expressed their immense need for lean, the level of its implementation is found to be very low. The findings could encourage further extensive studies to develop strategies to promote the use of lean in these countries.     

Pareto efficient allocation of an in-motion wireless charging infrastructure for electric vehicles in a multipath network

Electric vehicles (EV) use an eco-friendly technology that limits the greenhouse gas emissions of the transport sector, but the limited battery capacity and the density of the battery are the major barriers to the widespread adoption of EV. To mitigate this, a good method seems to be the innovative wireless charging technology called ‘On-Line EV (OLEV)’, which is a contactless electric power transfer technology. This EV technology has the potential to charge the vehicle’s battery dynamically while the vehicle is in motion. This system helps to reduce not only the size of the battery but also its cost, and it also contributes to extending the driving range before the EV has to stop. The high cost of this technology requires an optimal location of the infrastructure along the route. For this reason, the objective of this paper is to study the problem of the location of the wireless charging infrastructure in a transport network composed of multiple routes between the origin and the destination. To find a strategic solution to this problem, we first and foremost propose a nonlinear integer programming solution to reach a compromise between the cost of the battery, which is related to its capacity, and the cost of installing the power transmitters, while maintaining the quality of the vehicle’s routing. Second, we adapt the multi-objective particle swarm optimization (MPSO) approach to our problem, as the particles were robust in solving nonlinear optimization problems. Since we have a multi-objective problem with two binary variables, we combine the binary and discrete versions of the particle swarm optimization approach with the multi-objective one. The port of Le Havre is presented as a case study to illustrate the proposed methodology. The results are analyzed and discussed in order to point out the efficiency of our resolution method.     

Predictors of export performance in developing economies: a longitudinal analysis of Moroccan SMEs

Purpose: To help increase understanding of the export performance, we investigate the influence of firm size, research and development (R&D), advertising expenditures and network relationships, and develop a conceptual model to increase export intensity. Design/methodology/approach: The research involved a four-year longitudinal study of export performance of 168 exporting SMEs in Morocco (672 observations). The two-stage least square estimation (G2SLS) was used to test the hypotheses. Findings: The findings of the two-stage least square estimation (G2SLS) suggest that export sales and domestic sales are interdependent and influence each other. R&D expenditures and network affiliation have positive and significant impact on export sales, while advertising expenditure has a negative and significant influence on export sales. Research limitations/implications: Readers should use caution in generalizing the findings unless verified in other developing contexts. Practical implications: The findings of this study are useful for managers and export policy makers in developing countries. A proper understanding of the predictors of export performance may help them encourage the growth and diversification of exports that is so vital for developing countries. Originality/value: Export performance is a key element in the field of international marketing. Unfortunately, the literature exhibits a lack of empirical studies in developing countries, particularly in Maghreb regions. The empirical testing of the theoretical model in a developing economy is a significant contribution to fill the needed gap in the literature toward generalizing findings.     

Macroprudential policy in a currency union

Review of World Economics - The past 20 years in Europe have seen large swings in real and financial markets, and sudden stops of capital flows have exposed the fault lines of the European...     

How do consumers categorize new hybrid products?

This article investigates how consumers categorize new hybrid products (NHPs). Given the limitations of the classical theories of categorization in the specific case of NHP, affordance, mobilized infrequently in marketing, turned out to be a useful categorization concept. Five types of NHP categorizations by consumers, based on the degree of affordance (low vs. high) and type of innovation (incremental vs. radical), have been detected and filled a gap in the literature on the subject.     

Dynamics of price level changes in the Visegrad group: comparative study

Quality & Quantity - In Poland, as in many other countries, to measure inflation, expressed both by the CPI and HICP, the Laspeyres price index with weights from the base period is used. Thus...     

The characteristic function of rough Heston models

It has been recently shown that rough volatility models, where the volatility is driven by a fractional Brownian motion with small Hurst parameter, provide very relevant dynamics in order to reproduce the behavior of both historical and implied volatilities. However, due to the non‐Markovian nature of the fractional Brownian motion, they raise new issues when it comes to derivatives pricing. Using an original link between nearly unstable Hawkes processes and fractional volatility models, we compute the characteristic function of the log‐price in rough Heston models. In the classical Heston model, the characteristic function is expressed in terms of the solution of a Riccati equation. Here, we show that rough Heston models exhibit quite a similar structure, the Riccati equation being replaced by a fractional Riccati equation.