A class of BIB designs with repeated blocks

Balanced incomplete block design (BIBD) with repeated blocks is studied in detail. Methods of construction of BIB designs with repeated blocks are developed so as to distinguish the usual BIBD and BIBD with repeated blocks. One additional parameter, say d, is considered here, where d denotes the number of distinct blocks present in the BIB design with repeated blocks. Further, a class of BIB design with parameters: v = 7, b = 28, r = 12, k = 3, λ= 4, has been constructed where, out of 15, 14 BIB designs have repeated blocks. These 15 BIB designs, which have the same parameters, are compared on the basis of number of distinct blocks (d) and the multiplicities of variance of elementary contrasts of the block effect.     

A Contingent View of Quality Management‐The Impact of International Competition on Quality

Much of the research on quality practices and performance reflects a resource‐based perspective of the firm, dealing primarily with internal issues of managerial and technological competence in developing and executing an effective TQM strategy. The neoclassical perspective on the influence of the competitive environment on quality practices and performance remains conspicuously absent in the empirical quality literature. Our study aims to address this gap by examining the contingent role of international competition on quality management and performance. We develop and test an integrative framework of quality management, consisting of high involvement work practices, quality practices, quality performance, and firm performance. We then examine the contingent effects of international competition on the constructs and relationships of the framework. International competition was found to moderate the relationship between quality practices and customer satisfaction performance, as well as the relationship between high involvement work practices and firm performance. The moderator effects suggest interesting implications for quality theory and practice.     

Non-concave penalization in linear mixed-effect models and regularized selection of fixed effects

Mixed-effect models are very popular for analyzing data with a hierarchical structure. In medical applications, typical examples include repeated observations within subjects in a longitudinal design, patients nested within centers in a multicenter design. However, recently, due to the medical advances, the number of fixed-effect covariates collected from each patient can be quite large, e.g., data on gene expressions of each patient, and all of these variables are not necessarily important for the outcome. So, it is very important to choose the relevant covariates correctly for obtaining the optimal inference for the overall study. On the other hand, the relevant random effects will often be low-dimensional and pre-specified. In this paper, we consider regularized selection of important fixed-effect variables in linear mixed-effect models along with maximum penalized likelihood estimation of both fixed and random-effect parameters based on general non-concave penalties. Asymptotic and variable selection consistency with oracle properties are proved for low-dimensional cases as well as for high dimensionality of non-polynomial order of sample size (number of parameters is much larger than sample size). We also provide a suitable computationally efficient algorithm for implementation. Additionally, all the theoretical results are proved for a general non-convex optimization problem that applies to several important situations well beyond the mixed model setup (like finite mixture of regressions) illustrating the huge range of applicability of our proposal.     

Career Adaptability and Occupational Engagement of Student Veterans

This study examined the specific career‐related behaviors of career adaptability and occupational engagement among student veterans (N = 100). Contrary to expectations, findings showed statistically significant negative correlations between career adaptability resources (control, concern, curiosity, and confidence) and occupational engagement. Multiple regression analyses indicated that the curiosity resource of career adaptability significantly predicted occupational engagement. The findings suggest a need to understand the complexity of career adaptability and occupational engagement in both research and practice for student veterans.     

The Gamma–Kumaraswamy distribution: An alternative to Gamma distribution

In this article, a new generalization of the Kumaraswamy distribution, namely the Gamma–Kumaraswamy distribution, is defined and studied. Various properties of the Gamma–Kumaraswamy are obtained. The structural analysis of the distribution in this article includes limiting behavior, mode, quantiles, moments, skewness, kurtosis, Shannon’s entropy, and order statistics. The method of maximum likelihood estimation is proposed for estimating the model parameters. For illustrative purposes, two real datasets are analyzed as application of the Gamma–Kumaraswamy distribution.     

On the Loss Robustness of Least-Square Estimators

Abstract

The article revisits univariate and multivariate linear regression models. It is shown that least-square estimators (LSEs) are minimum risk estimators in general class of linear unbiased estimators under some general divergence loss. This amounts to the loss robustness of LSEs.     

Influence of soil properties on street tree attributes in Singapore

Urban Ecosystems - Soil quality is thought to be a primary driver of street tree performance and thus a major concern for urban forest growth, health and longevity. This research was conducted to...     

Change-point problems for the von Mises distribution

A generalized likelihood ratio procedure and a Bayes procedure are considered for change-point problems for the mean direction of the von Mises distribution, both when the concentration parameter is known and when it is unknown. These tests are based on sample resultant lengths. Tables that list critical values of these test statistics are provided. These tests are shown to be valid even when the data come from other similar unimodal circular distributions. Some empirical studies of powers of these test procedures are also incorporated.     

Floristic and structural differentiation between gardens of primary and secondary residences in the Costa Brava (Catalonia,Spain)

Urban Ecosystems - Urban sprawl along the Mediterranean coast is characterized by single-family houses and domestic gardens. Many new residences are secondary homes for socio-demographically...