Optimality results on orthogonal arrays plus <Emphasis Type="Italic">p</Emphasis> runs for <Emphasis Type="Italic">s</Emphasis><Superscript><Emphasis Type="Italic">m</Emphasis></Superscript> factorial experiments

The optimality of designs obtained by adding p runs to an orthogonal array is studied for experiments involving m factors each at s levels. The optimality criterion used here, is the Type 1 criterion due to Cheng (1978) which is an extension of Kiefer (1975) universal optimality criterion. Unlike what happens with orthogonal array plus one run designs, the behavior of designs obtained via augmentation of an orthogonal array by p runs depends on the particular runs added.     

Inference by the <Emphasis Type="Italic">m</Emphasis> out of <Emphasis Type="Italic">n</Emphasis> bootstrap in nonparametric frontier models

It is well-known that the naive bootstrap yields inconsistent inference in the context of data envelopment analysis (DEA) or free disposal hull (FDH) estimators in nonparametric frontier models. For inference about efficiency of a single, fixed point, drawing bootstrap pseudo-samples of size m < n provides consistent inference, although coverages are quite sensitive to the choice of subsample size m. We provide a probabilistic framework in which these methods are shown to valid for statistics comprised of functions of DEA or FDH estimators. We examine a simple, data-based rule for selecting m suggested by Politis et al. (Stat Sin 11:1105–1124, 2001), and provide Monte Carlo evidence on the size and power of our tests. Our methods (i) allow for heterogeneity in the inefficiency process, and unlike previous methods, (ii) do not require multivariate kernel smoothing, and (iii) avoid the need for solutions of intermediate linear programs.     

Measuring process capability index <Emphasis Type="Italic">C</Emphasis><Subscript><Emphasis Type="Italic">pm</Emphasis></Subscript> with fuzzy data

The process capability index C _pm , which considers the process variance and departure of the process mean from the target value, is important in the manufacturing industry to measure process potential and performance. This paper extends its applications to calculate the process capability index [(C)\tilde]_pm{\tilde {C}_{pm} } of fuzzy numbers. In this paper, the α-cuts of fuzzy observations are first derived based on various values of α. The membership function of fuzzy process capability index [(C)\tilde]_pm{\tilde {C}_{pm} } is then constructed based on the α-cuts of fuzzy observations. An example is presented to demonstrate how the fuzzy process capability index [(C)\tilde]_pm{\tilde {C}_{pm} } is interpreted. When the quality characteristic cannot be precisely determined, the proposed method provides the most possible value and spread of fuzzy process capability index [(C)\tilde]_pm{\tilde {C}_{pm} }. With crisp data, the proposed method reduces to the classical method of process capability index C _pm .     

Top-<Emphasis Type="Italic">k</Emphasis>-lists

Top-k-lists are introduced as sequences of k-dimensional random vectors with ordered components being k largest observations from a sequence of independent identically distributed random variables. Such lists changing in time are natural stochastic models of ranking tables which appear in many situations in real life, when one wants to keep a track of several best results in a given field. Here we study basic properties of top-k-lists as joint distributions, conditional structures, representations, driving examples of top-k-lists from exponential and uniform distributions, asymptotics and a relation to generalized order statistics.     

Bayesian estimation of log odds ratios from R × C and 2 × 2 × K contingency tables

In this paper, Bayesian estimation of log odds ratios over R × C and 2 × 2 × K contingency tables is considered, which is practically reasonable in the presence of prior information. Likelihood functions for log odds ratios are derived for each table structure. A prior specification strategy is proposed. Posterior inferences are drawn using Gibbs sampling and Metropolis–Hastings algorithm. Two numerical examples are given to illustrate the matters argued.     

Maximal Rank Minimum Aberration Foldover Plans for 2<Superscript><Emphasis Type="Italic">m</Emphasis>-<Emphasis Type="Italic">k</Emphasis></Superscript> Fractional Factorial Designs

Two level regular fractional factorial designs are often used in industry as screening designs to help identify early on in an experimental process those experimental or system variables which have significant effects on the process being studied. In a recent paper, Li and Lin (2003) suggested a strategy for constructing optimal follow up designs using the well known foldover technique and the minimum aberration criterion. In this paper, we extend the results of Li and Lin (2003) by giving an alternate technique for constructing optimal follow up designs using the foldover technique in conjunction with the maximal rank–minimum aberration criterion suggested in Jacroux (2003).     

The ‘science’ and ‘practice’ of HRM in small firms

This paper looks at the ‘science’ and ‘practice’ of human resource management in small firms. While there is growing evidence that the practice of human resource management in small firms is characterized by informality, there is less evidence about the science, or explaining why this is the case. We look to writing on strategic human resource management, which has at its heart the resource based view of the firm, for possibilities offered to understanding the science of human resource management in small firms.     

¿Está adoptando Asia la «flexiseguridad»?

Incitados por la competencia mundial, muchos países están adaptando la reglamentación laboral al principio de la «flexiseguridad>>, que da a las empresas más flexibilidad para contratar y despedir a los trabajadores, al tiempo que ampara a éstos cuando deben pasar de un empleo a otro. El presente estudio de seis países asiáticos indica que China y República de Corea han promulgado reformas de este género; Singapur y Malasia han implantado algunos elementos de «flexiseguridad>>, pero no un seguro de desempleo, y la India y Sri Lanka han hecho pocas reformas y mantienen un modelo anticuado en el que la protección depende de la empresa. Para prestar apoyo a los trabajadores del sector informal, China, India y Sri Lanka se valen de obras públicas y de programas de fomento del trabajo por cuenta propia y de formación profesional.     

‘Repeat commercializers,’ the ‘habitual entrepreneurs’ of university–industry technology transfer

Among academic faculty, is there a class of ‘repeat commercializers’ who account for a disproportionate share of commercialized technologies arising from university research? In a survey of 172 engineering, mathematics, and science faculty members from a major Canadian university, we found evidence that a class of repeat commercializers does exist. Further, we found that the 12% of the faculty who are repeat commercializers account for 80% of the commercialized innovations. Interviews with repeat commercializers in the same faculties at the same university suggest that repeat commercializers parallel habitual entrepreneurs in that they have the ability to commercialize (i.e. the ability to generate and identify commercializable inventions and the ability to acquire resources for the commercialization of their inventions) and the aspiration to do so (i.e. commercialization-friendly attitudes). Since repeat commercializers account for such a large percentage of commercialization activity, it is important that programs and policies associated with technology transfer address the needs of this subpopulation of the faculty.     

Two-stage DEA: <Emphasis Type="Italic">caveat emptor</Emphasis>

This paper examines the wide-spread practice where data envelopment analysis (DEA) efficiency estimates are regressed on some environmental variables in a second-stage analysis. In the literature, only two statistical models have been proposed in which second-stage regressions are well-defined and meaningful. In the model considered by Simar and Wilson (J Prod Anal 13:49–78, 2007), truncated regression provides consistent estimation in the second stage, where as in the model proposed by Banker and Natarajan (Oper Res 56: 48–58, 2008a), ordinary least squares (OLS) provides consistent estimation. This paper examines, compares, and contrasts the very different assumptions underlying these two models, and makes clear that second-stage OLS estimation is consistent only under very peculiar and unusual assumptions on the data-generating process that limit its applicability. In addition, we show that in either case, bootstrap methods provide the only feasible means for inference in the second stage. We also comment on ad hoc specifications of second-stage regression equations that ignore the part of the data-generating process that yields data used to obtain the initial DEA estimates.     

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.      

Raising the Regional Leviathan: A Relational‐Materialist Conceptualization of Regions‐in‐Becoming as Publics‐in‐Stabilization

The purpose of this article is to contribute to the understanding of how spatial entities in general — and those spatial entities that are defined as ‘regions’ in particular — form, evolve and sometimes stabilize. Inspired by the scholarship of Noortje Marres, the article explores how regions‐in‐becoming may be gainfully conceptualized as publics‐in‐stabilization. In the article it is argued that some of the mechanisms involved in such processes pertain to how territorially framed issues sometimes become formulated as loosely articulated propositions for regionalization. These can, with time, generate emergent stakeholder communities, which in turn may become stabilized and delegated to more durable forms and materials which can eventually become naturalized as recognized regions. A suggested conceptual model is utilized to perform an analysis of empirical material from three contemporary processes of regionalization in Northern Europe with the purpose of examining and discussing some of the potential merits and shortcomings of the conceptual model. It is concluded that adopting the proposed perspective can enable scholars to highlight some of the mechanisms whereby vague and non‐coherent propositions for regionalization within time may be singularized and stabilized to such a degree that they become taken for granted as naturalized spatialities.     

The sophistication of ‘naive’ modeling

The relatively high predictive power of a naive market share model is due to (1) its similarity to the reduced form representation of the underlying model and (2) the comparison with forecasts generated from structural models that are likely to be misspecified.