Efficiency of Even Separation of Parallel Elements with Variable Contest Intensity

The article considers strategic defense and attack of a system that can be separated into parallel elements. The defender distributes its resource between separation and protecting the elements from outside attacks. The vulnerability of each element is determined by an attacker‐defender contest success function, which depends on a contest intensity that may increase or decrease through the separation process. The article determines criteria of separation efficiency for systems without performance redundancy and 1‐out‐of‐N and Q‐out‐of‐N systems with performance redundancy. For the systems with performance redundancy the cases of expected damage proportional to the probability that the demand is not met, and expected damage proportional to the unsupplied demand, are considered.     

Developing criteria for healthy organizational change

Abstract

The objective of this study was to identify criteria for healthy change in organizations and to develop practical guidelines for intended change. We aimed to explore how change processes at the shop floor level can be better informed by consultants and labour inspectors. A total of 180 interviews were conducted with managers and employees in 90 units of public and private organizations in Norway. The interviews were analysed through four steps representing an expansion of grounded theory, and converted to qualitative analysis using QSR and N6 software. We found that organizational change processes were better managed by more attention to awareness of the local norms and diversity among employees in the perception and reactions to change efforts. An inspector or consultant should be aware of these phenomena in any change effort and tell the organization how to deal with them. The other three factors identified were early role clarification, manager availability, and using constructive conflicts to deal with change. They are all important coping mechanisms at the organizational level that will bring change processes onto a more optimal track if correctly managed. A healthy process empowers individuals instead of making them insecure and defensive in times of change. This will help them restore perceived control and promote job security, which benefits both them and the organization.     

Optimal design in average for inference in generalized linear models

This paper considers the problem of optimal design for inference in Generalized Linear Models, when prior information about the parameters is available. The general theory of optimum design usually requires knowledge of the parameter values. These are usually unknown and optimal design can, therefore, not be used in practice. However, one way to circumvent this problem is through so-called “optimal design in average”, or shortly, “ave optimal”. The ave optimal design is chosen to minimize the expected value of some criterion function over a prior distribution. We focus our interest on the aveD _A-optimality, including aveD- and avec-optimality and show the appropriate equivalence theorems for these optimality criterions, which give necessary conditions for an optimal design. Ave optimal designs are of interest when e.g. a factorial experiment with a binary or a Poisson response in to be conducted. The results are applied to factorial experiments, including a control group experiment and a 2×2 experiment.     

Prosodic Modification and Vocal Adjustments in Mothers' Speech During Face‐to‐face Interaction with Their Two‐ to Four‐month‐old Infants: A Double Video Study

The purpose of this study was to examine 32 mothers' sensitivity to social contingency during face‐to‐face interaction with their two‐ to four‐month‐old infants in a closed circuit TV set‐up. Prosodic qualities and vocal sounds in mother's infant‐directed (ID) speech during sequences of live interaction were compared to sequences where expressive behaviours were decoupled by presenting either the mothers (Replay 2) or the infants (Replay 1) with a replay record of the partners' former behaviour in a Live 1–Replay 1–Live 2–Replay 2–Live 3 design. Overall, the mothers produced significantly higher amount of ID speech during the live sequences. Compared to the Live 1 sequence, there was a significant reduction in mothers' ID speech during both replay sequences. However, the mothers only recovered ID speech after the Replay 2 sequence, not after the Replay 1. These findings suggest that the emotions signalled by the mothers' ID speech is affected by the contingency of the infant responses.     

SHRINKAGE, PRETEST AND ABSOLUTE PENALTY ESTIMATORS IN PARTIALLY LINEAR MODELS

We consider a partially linear model in which the vector of coefficients β in the linear part can be partitioned as ( β ₁, β ₂) , where β ₁ is the coefficient vector for main effects (e.g. treatment effect, genetic effects) and β ₂ is a vector for ‘nuisance’ effects (e.g. age, laboratory). In this situation, inference about β ₁ may benefit from moving the least squares estimate for the full model in the direction of the least squares estimate without the nuisance variables (Steinian shrinkage), or from dropping the nuisance variables if there is evidence that they do not provide useful information (pretesting). We investigate the asymptotic properties of Stein‐type and pretest semiparametric estimators under quadratic loss and show that, under general conditions, a Stein‐type semiparametric estimator improves on the full model conventional semiparametric least squares estimator. The relative performance of the estimators is examined using asymptotic analysis of quadratic risk functions and it is found that the Stein‐type estimator outperforms the full model estimator uniformly. By contrast, the pretest estimator dominates the least squares estimator only in a small part of the parameter space, which is consistent with the theory. We also consider an absolute penalty‐type estimator for partially linear models and give a Monte Carlo simulation comparison of shrinkage, pretest and the absolute penalty‐type estimators. The comparison shows that the shrinkage method performs better than the absolute penalty‐type estimation method when the dimension of the β ₂ parameter space is large.     

Subjective Economic Status in Adolescence: Determinants and Associations with Mental Health in the Norwegian Youth@Hordaland Study

We aimed to identify factors associated with perceived economic well-being (PEWB), and examine its association with symptoms of depression and attention-deficit/hyperactivity disorder. In the Norwegian youth@hordaland study, 9166 16–19-year-olds provided information on perceived economic well-being and relevant covariates. Information about families’ income-to-needs was obtained from tax return forms. Adolescents in households with a low income-to-needs ratio, with non-working parents, and in single-parent households were more likely to report poor PEWB. Adolescents with poor PEWB reported more symptoms of depression and ADHD, also after adjusting for covariates, including income-to-needs. There was a significant indirect effect of income-to-needs on mental health problems though PEWB. The current study demonstrates the role of PEWB as a contributor in the pathway from social inequalities to disparities in mental health.     

Estimation in proportional hazard and log-linear models

Proportional hazard models and models where the dependent variables follow a linear model are shown to be equivalent if and only if the hazard rate is the product of a non-negative periodic function and a Weibull factor. Estimates based on rank statistics are proposed for the parameters in the proportional hazard model.     

On variable bandwidth selection in local polynomial regression

The performances of data-driven bandwidth selection procedures in local polynomial regression are investigated by using asymptotic methods and simulation. The bandwidth selection procedures considered are based on minimizing 'prelimit' approximations to the (conditional) mean-squared error (MSE) when the MSE is considered as a function of the bandwidth h . We first consider approximations to the MSE that are based on Taylor expansions around h=0 of the bias part of the MSE. These approximations lead to estimators of the MSE that are accurate only for small bandwidths h . We also consider a bias estimator which instead of using small h approximations to bias naïvely estimates bias as the difference of two local polynomial estimators of different order and we show that this estimator performs well only for moderate to large h . We next define a hybrid bias estimator which equals the Taylor-expansion-based estimator for small h and the difference estimator for moderate to large h . We find that the MSE estimator based on this hybrid bias estimator leads to a bandwidth selection procedure with good asymptotic and, for our Monte Carlo examples, finite sample properties.     

A process evaluation of individual and organizational occupational stress and health interventions

There is reason to believe that many health and stress interventions fail due to inattention to the effects of intervention implementation processes, but evaluations of these processes are found only rarely in the literature. The objective of the present study was to explore the issue of obstacles to implementation that may occur when stress and health interventions are introduced in work organizations. The study was conducted as a process evaluation of seven different individual and organizational interventions. Interviews were conducted in 22 post offices, 12 organizational units (such as care homes and local administrative units) of a Norwegian municipality, and in 10 shops in a shopping mall. The interviews took place before and after the interventions. The following key process factors were identified: (1) the ability to learn from failure and to motivate participants; (2) multi-level participation and negotiation, and differences in organizational perception; (3) insight into tacit and informal organizational behaviour; (4) clarification of roles and responsibilities, especially the role of middle management; and (5) competing projects and reorganization. For improved studies of interventions in the future we recommend that qualitative and quantitative methods be combined, that researchers build more on natural interventions that occur naturally within the organization, and that a pilot study be undertaken in order to investigate the cultural maturity of the organization.