U-type and column-orthogonal designs for computer experiments

U-type designs and orthogonal Latin hypercube designs (OLHDs) have been used extensively for performing computer experiments. Both have good spaced filling properties in one-dimension. U-type designs may not have low correlations among the main effects, quadratic effects and two-factor interactions. On the other hand, OLHDs are hard to be found due to their large number of levels for each factor. Recently, alternative classes of U-type designs with zero or low correlations among the effects of interest appear in the literature. In this paper, we present new classes of U-type or quantitative \(3\) -orthogonal designs for computer experiments. The proposed designs are constructed by combining known combinatorial structures and they have their main effects pairwise orthogonal, orthogonal to the mean effect, and orthogonal to both quadratic effects and two-factor interactions.     

Dismantled Spatial Fixes in the Aftermath of Recession: Capital Switching and Labour Underutilization in the Greek Capital Metropolitan Region

The article offers a fresh, empirically grounded look at the spatialities of crisis‐triggered employment forms—a largely overlooked issue in contemporary critical geography literature. Specifically, it discusses the interconnection between investment flows from manufacturing to the built environment (capital switching) and underemployment in urban metropolitan regions to substantiate its impact on emerging spatial fixities. The article, which is based on an empirical analysis informed by a radical political economy, investigates changing fixed capital formations in Greece over an extended period prior to and during the recession, from 1995 to 2012. It traces the evolution of part‐time waged work in the capital metropolitan region of Attica (Athens) vis‐à‐vis the rest of the country's regional labour markets, focusing on the polarized 2005–2012 period and the demise of the construction industry. The article highlights that ‘disrupted’ capital switching that occurred in Greece, closely associated with recalibrated sectoral priorities and institutional interventions, resulted in the uneven sprawling of underemployment. Our findings offer insight into how the dismantling of spatial fixes within core metropolitan regions of the southern European Union (and beyond) are connected to labour surplus and successive slumps in manufacturing and construction. The article closes by calling for new theorizations of contemporary urban regional unevenness and its spatiotemporal fixities, which account for the role of changes in labour turnover time.     

On the construction of <Emphasis Type="Italic">E</Emphasis>(<Emphasis Type="Italic">s</Emphasis><Superscript>2</Superscript>)-optimal supersaturated designs

Supersaturated designs are an important class of factorial designs in which the number of factors is larger than the number of runs. These designs supply an economical method to perform and analyze industrial experiments. In this paper, we consider generalized Legendre pairs and their corresponding matrices to construct E(s ²)-optimal two-level supersaturated designs suitable for screening experiments. Also, we provide some general theorems which supply several infinite families of E(s ²)-optimal two-level supersaturated designs of various sizes.      

Nonparametric tests for Optimal Predictive Ability

A nonparametric method for comparing multiple forecast models is developed and implemented. The hypothesis of Optimal Predictive Ability generalizes the Superior Predictive Ability hypothesis from a single given loss function to an entire class of loss functions. Distinction is drawn between General Loss functions, Convex Loss functions, and Symmetric Convex Loss functions. The research hypothesis is formulated in terms of moment inequality conditions. The empirical moment conditions are reduced to an exact and finite system of linear inequalities based on piecewise-linear loss functions. The hypothesis can be tested in a statistically consistent way using a blockwise Empirical Likelihood Ratio test statistic. A computationally feasible test procedure computes the test statistic using Convex Optimization methods, and estimates conservative, data-dependent critical values using a majorizing chi-square limit distribution and a moment selection method. An empirical application to inflation forecasting reveals that a very large majority of thousands of forecast models are redundant, leaving predominantly Phillips Curve-type models, when convexity and symmetry are assumed.     

Hybrid particle swarm optimization with mutation for optimizing industrial product lines: An application to a mixed solution space considering both discrete and continuous design variables

This article presents an artificial intelligence-based solution to the problem of product line optimization. More specifically, we apply a new hybrid particle swarm optimization (PSO) approach to design an optimal industrial product line. PSO is a biologically-inspired optimization framework derived from natural intelligence that exploits simple analogues of collective behavior found in nature, such as bird flocking and fish schooling. All existing product line optimization algorithms in the literature have been so far applied to consumer markets and product attributes that range across some discrete values. Our hybrid PSO algorithm searches for an optimal product line in a large design space which consists of both discrete and continuous design variables. The incorporation of a mutation operator to the standard PSO algorithm significantly improves its performance and enables our mechanism to outperform the state of the art Genetic Algorithm in a simulated study with artificial datasets pertaining to industrial cranes. The proposed approach deals with the problem of handling variables that can take any value from a continuous range and utilizes design variables associated with both product attributes and value-added services. The application of the proposed artificial intelligence framework yields important implications for strategic customer relationship and production management in business-to-business markets.     

MODELLING BANKS' LENDING BEHAVIOUR IN A CAPITAL‐REGULATED FRAMEWORK

This paper adds to the literature on the money supply theory by assessing the effect of banks' equity on the loan generating process. First, a new ‘credit’ multiplier is examined, the so‐called ‘equity’ multiplier model. This, in a second stage, is incorporated in a new multivariate lending model. The models are assessed by using panel data cointegration techniques for the G7 countries. According to our results, a feedback relationship exists between banks' loans and equity. Moreover, the factors determining loans are: the aggregate demand, the loan–customer relation, the banks' equity and banks' portfolio adjustments and/or the monetary stance.     

The role of news-based uncertainty indices in predicting oil markets: a hybrid nonparametric quantile causality method

A recent strand in the literature emphasizes the role of news-based economic policy uncertainty (EPU) and equity market uncertainty (EMU) as drivers of oil price movements. Against this backdrop, this paper uses a kth-order nonparametric quantile causality test, to analyse whether EPU and EMU predict stock returns and volatility. Based on daily data covering the period of 2 January 1986 to 8 December 2014, we find that, for oil returns, EPU and EMU have strong predictive power over the entire distribution barring regions around the median, but for volatility, the predictability virtually covers the entire distribution, with some exceptions in the tails. In other words, predictability based on measures of uncertainty is asymmetric over the distribution of oil returns and its volatility.     

Single Versus Multi-market Approach: An Application to the Greek Cotton Market

Estimation of the price-induced welfare effects in vertical and horizontal market settings may prove a tricky task when multiple price changes are taken into account. Whether a multi-market sequential approach or a single-market approach is used the well-established, theoretical result suggests that these two partial equilibrium methods are equivalent in terms of implied welfare changes. This paper develops the methodology to empirically compare these two methods. We estimate the welfare changes to Greek cotton–yarn producers induced by the simultaneous change in the prices of cotton–yarn and the cost of labor. Results substantiate the multi-market approach offers more accurate welfare estimates than the single-market approach, in empirical work.

Ethical Distance in Corrupt Firms: How Do Innocent Bystanders Become Guilty Perpetrators?

This paper develops the concept of the ‘continuum of destructiveness’ in relation to organizational corruption. This notion captures the slippery slope of wrongdoing as actors engage in increasingly dubious practices. We identify four kinds of individuals along this continuum in corrupt organizations, who range from complete innocence to total guilt. They are innocent bystanders, innocent participants, active rationalizers and guilty perpetrators. Traditional explanations of how individuals move from bystander status to guilty perpetrators usually focus on socialization and institutional factors. In addition to these factors, we propose that the very distance between an act and its ethical consequences (ethical distance) may also play a determining role – if not always in the same way – in the transition process. Having developed this conceptual argument, we conclude with a discussion of managerial and research implications. An Earlier version of this paper was presented at the The Twelfth Annual International Conference Promoting Business Ethics, New York, October 2005     

AN EVALUATION OF THE GREEK UNIVERSITIES’ ECONOMICS DEPARTMENTS

This study provides a ranking of Economics Departments of Greek universities. Contrary to the existing literature, we look directly at the citations of the faculty members as a measure of academic performance and avoid the classification of journals. Additionally, the country of the PhD studies was found to be a significant variable that can explain the productivity of Greek economists. PhD holders from US and UK universities are characterized by higher productivity compared to those from other countries.