Mean–variance and mean–semivariance portfolio selection: a multivariate nonparametric approach

While univariate nonparametric estimation methods have been developed for estimating returns in mean-downside risk portfolio optimization, the problem of handling possible cross-correlations in a vector of asset returns has not been addressed in portfolio selection. We present a novel multivariate nonparametric portfolio optimization procedure using kernel-based estimators of the conditional mean and the conditional median. The method accounts for the covariance structure information from the full set of returns. We also provide two computational algorithms to implement the estimators. Via the analysis of 24 French stock market returns, we evaluate the in-sample and out-of-sample performance of both portfolio selection algorithms against optimal portfolios selected by classical and univariate nonparametric methods for three highly different time periods and different levels of expected return. By allowing for cross-correlations among returns, our results suggest that the proposed multivariate nonparametric method is a useful extension of standard univariate nonparametric portfolio selection approaches.     

An Approach to Security for Unstructured Big Data

Security of Big Data is a huge concern. In a broad sense, Big Data contains two types of data: structured and unstructured. Providing security to unstructured data is more difficult than providing security to structured data. In this paper, we have developed an approach to provide adequate security to unstructured data by considering types of data and their sensitivity levels. We have reviewed the different analytics methods of Big Data to build nodes of different types of data. Each type of data has been classified to provide adequate security and enhance the overhead of the security system. To provide security to a data node, and a security suite has been designed by incorporating different security algorithms. Those security algorithms collectively form a security suite which has been interfaced with the data node. Information on data sensitivity has been collected through a survey. We have shown through several experiments on multiple computer systems with varied configurations that data classification with respect to sensitivity levels enhances the performance of the system. The experimental results show how and in what amount the designed security suite reduces overhead and increases security simultaneously.     

Forecasting technology diffusion: a new generalisation of the logistic model

The present research proposes a new generalisation of the logistic model aiming at technology diffusion forecasting. Regarding criticisms and failures reported in the literature to apply logistic function for long-term forecasting, in our work we focused on short-term accuracy of forecast. To formulate the model, based on mathematical approximation, at first the differential equation governing the diffusion process is found and then by solving the derived differential equation, the forecast function is obtained. In all steps, mathematical tools from numerical analysis are used. We compared the New Generalized Logistic Model with eight of the most renowned models in the literature. The model led to more accurate fits and forecasts than those obtained from other models we applied for comparison.     

Competitive strategies,innovation, and firm performance: an empirical study in a developing economy environment

This paper studies the relationships between competitive strategies, innovation, and firm performance within the context of Turkish manufacturing companies. The data were collected from top management of the firms via Computer Assistant Telephone Interviewing method. One hundred and forty manufacturing firms operating in various sectors including textile, automotive supply, computer and electronics provide the basis for this empirical research. In order to test our model, we employ structural equation modelling using partial least squares. The results show that competitive strategies such as cost-leadership and differentiation can lead to innovation, which, in turn, increase firm performance. Managers implement cost-leadership and differentiation strategies to take part in competitive market conditions; however, they should put additional importance on innovation that plays a significant role as a bridge between competitive strategies and firm performance.     

A Pyramid of Hate Perspective on Religious Bias,Discrimination and Violence

Journal of Business Ethics - This study provides a ‘pyramid of hate’ perspective on issues and challenges facing minority religious communities in social and political climates that...     

Migration and employment interactions in a crisis context

This article analyses how a crisis impacts labour markets in origin countries through migration channels. For this purpose, we develop a novel dynamic general equilibrium model with a focus on the interlinkages between migration, the labour market and education. The main innovation of the paper is the retrospective modelling in general equilibrium of the impact of an economic crisis to isolate the impact of migration on local unemployment. The impact of the crisis on education decision is captured through endogenous returns to education. The simultaneity of the crisis in Tunisia and its partners worsened the labour market situation mainly through the increase in labour supply. The main result of this study is that migration is indeed one of the main determinants of the unemployment increase and that remittances have a higher impact than the variation of emigration flows. The low skilled bear the highest costs in terms of unemployment and wage decline.     

You May Not Reap What You Sow: How Employees’ Moral Awareness Minimizes Ethical Leadership’s Positive Impact on Workplace Deviance

Although a growing body of research has shown the positive impact of ethical leadership on workplace deviance, questions remain as to whether its benefits are consistent across all situations. In this investigation, we explore an important boundary condition of ethical leadership by exploring how employees’ moral awareness may lessen the need for ethical leadership. Drawing on substitutes for leadership theory, we suggest that when individuals already possess a heightened level of moral awareness, ethical leadership’s role in reducing deviant actions may be reduced. However, when individuals lack this strong moral disposition, ethical leadership may be instrumental in inspiring them to reduce their deviant actions. To enhance the external validity and generalizability of our findings, the current research used two large field samples of working professionals in both Turkey and the USA. Results suggest that ethical leadership’s positive influence on workplace deviance is dependent upon the individual’s moral awareness—helpful for those employees whose moral awareness is low, but not high. Thus, our investigation helps to build theory around the contingencies of ethical leadership and the specific audience for whom it may be more (or less) influential.     

Why do firms delete brands? Insights from a qualitative study

Large consumer goods firms manage and market an assortment of brands and consistently deal with strategic challenges related to brand portfolio management, such as creating or acquiring brands, growing brand equity, managing brands in the portfolio and deleting brands. There is substantial research on several areas of brand portfolio management except in the area of brand deletion. This situation exists despite the fact that deleting weak brands has important implications for a firm and its brand portfolio. Therefore, it is critical to understand why firms delete brands from their portfolios. This research applies a qualitative approach using semi-structured interviews and thematic analysis in the context of firms that adopt a ‘house of brands’ brand architecture and presents findings guided by the strategic decision-making literature.