Exhaustive k-nearest-neighbour subspace clustering

Cluster analysis is an important technique of explorative data mining. It refers to a collection of statistical methods for learning the structure of data by solely exploring pairwise distances or similarities. Often meaningful structures are not detectable in these high-dimensional feature spaces. Relevant features can be obfuscated by noise from irrelevant measurements. These observations led to the design of subspace clustering algorithms, which can identify clusters that originate from different subsets of features. Hunting for clusters in arbitrary subspaces is intractable due to the infinite search space spanned by all feature combinations. In this work, we present a subspace clustering algorithm that can be applied for exhaustively screening all feature combinations of small- or medium-sized datasets (approximately 30 features). Based on a robustness analysis via subsampling we are able to identify a set of stable candidate subspace cluster solutions.     

Migration Decisions Within Dual‐Earner Partnerships: A Test of Bargaining Theory

This article focuses on the problems faced by dual‐earner partnerships arising from the regional coordination of the partners' careers. It is still unknown whether the fact that couples are less mobile than singles is caused by homogeneous preferences within couples or by a process of balancing conflicting interests. Consequently, we analyze the potential conflicts provoked by work‐related migration incentives. We test hypotheses derived from bargaining theory using quasi‐experimental data from a factorial survey of nearly 280 European couples. Our results support the bargaining approach and confirm that asymmetrical shifts in bargaining power drive the potential for conflict. Women's willingness to move is generally less than men's, but the impact of employment prospects differs only slightly by gender.     

‘We have very different positions on some issues’: how child welfare workers in Norway and England bridge cultural differences when communicating with ethnic minority families

This article compares how child welfare workers in Norway and England experience and cope with communication problems resulting from cultural differences. This study is based on in-depth, semi-structured interviews with 53 front-line child welfare workers and draws on social theories that understand communication as a social act. We show cross-country variations in child welfare workers' perceptions of the communicative problems and coping mechanisms. In Norway, social workers think that minority parents' perceptions on children's needs and child-rearing and parents' lack of understanding of the child welfare system were challenging. Social workers in England perceive the physical abuse of minority children as problematic. They are also concerned about carers' fears of social workers forcing majority cultural values on minority families. While social workers in both countries spend more time with minority families, their approaches dealing with communication challenges correspond to their different problem perceptions. Social workers in Norway act as cultural instructors: they focus on the needs of the minority child and instruct parents about Norwegian values and the Norwegian welfare system. Social workers in England are cultural learners: they focus on practising in anti-oppressive ways, while protecting ethnic minority children from physical abuse. Both approaches avoid going into real communication about perceived problems and what a child might need. We also discuss the implications of these findings on social work practice.     

Doubled Homes — Doubled Social Ties? Children's Relationships in Post‐Divorce Shared Residence Arrangements

Although an increasing number of children live in shared residence arrangements after parental divorce, studies on their social relationships are rare. We address this research gap by relying on configurational approaches, social capital and social networks. Building on qualitative case studies (ego‐centred networks, interviews) with 14 children aged 10–14, results show that respondents constructed social ties based on two key categories: emotional closeness and constancy. Having two places of residence did not multiply close relations, and relations that entered the network after parental divorce (e.g. step kin) were particularly distant. Children's networks at both homes had limited interconnections.     

The Development and Implementation of a Multi‐Couple Therapy Model with Torture Survivors in the Democratic Republic of the Congo

In this article, we present development and feasibility of implementation of a multi‐couple group for use with torture‐surviving couples. The model was developed in the Democratic Republic of the Congo in a community that experienced widespread torture during the wars from 1998 to 2004. The Torture‐Surviving Couple Group model is a short‐term intervention designed to use few human resources to address relational difficulties resulting from exposure to traumatic stressors. The model was guided by critical and feminist epistemologies and employed an ecological lens to incorporate neurobiology and attachment processes along with narrative therapy techniques. An existing multi‐couple group model for addressing violence (Stith, Rosen, McCollum, & Thomsen, 2004 ), and a stage model for healing trauma (Herman, 1992 ) also informed the structural development of the Torture‐Surviving Couple Group model. Couple groups were conducted using a 10‐session program with 13 couples who met weekly. Session themes were incorporated into four phases emphasizing: (a) preparation; (b) safety and stabilization; (c) processing the relationship effects of trauma and grief; and (d) reintegration and rebuilding couple and family life. Couples reported and showed remarkable progress in their relationships after participating in the groups. Clinical and research implications and discussed along with the feasibility of developing and testing the model in a post‐conflict low income setting.     

Die Coachingkultur als Wirkfaktor

The coaching culture as an impact factor on the efficacy of Coaching has rarely been addressed in scientific research so far. This article differentiates the coaching culture in aspects of the organizational embedding and attitudes towards coaching. The results of the quantitative study, where N = 49 members of organizations took part, show that the coaching processes are conducted in diverse ways, that the format is being applied for a broad range of issues and that the attitudes towards coaching lead into a positive direction. As a significant predictor for the judgement of coaching effects the reputation of the format in the organization was identified.     

Work Incentives at the Extensive and Intensive Margin in Europe: The Role of Taxes,Benefits and Population Characteristics

Social Indicators Research - Tax and benefit systems play an important role in determining work incentives at both the extensive and the intensive margin of labour supply. The aim of this paper is...     

Model distances for vine copulas in high dimensions

Vine copulas are a flexible class of dependence models consisting of bivariate building blocks and have proven to be particularly useful in high dimensions. Classical model distance measures require multivariate integration and thus suffer from the curse of dimensionality. In this paper, we provide numerically tractable methods to measure the distance between two vine copulas even in high dimensions. For this purpose, we consecutively develop three new distance measures based on the Kullback–Leibler distance, using the result that it can be expressed as the sum over expectations of KL distances between univariate conditional densities, which can be easily obtained for vine copulas. To reduce numerical calculations, we approximate these expectations on adequately designed grids, outperforming Monte Carlo integration with respect to computational time. For the sake of interpretability, we provide a baseline calibration for the proposed distance measures. We further develop similar substitutes for the Jeffreys distance, a symmetrized version of the Kullback–Leibler distance. In numerous examples and applications, we illustrate the strengths and weaknesses of the developed distance measures.     

Identifying Nonproportional Covariates in the Cox Model

This paper addresses problem of testing whether an individual covariate in the Cox model has a proportional (i.e., time-constant) effect on the hazard. Two existing methods are considered: one is based on the component of the score process, and the other is a Neyman type smooth test. Simulations show that, when the model contains both proportional and nonproportional covariates, these methods are not reliable tools for discrimination. A simple yet effective solution is proposed based on smooth modeling of the effects of the covariates not in focus.     

Sex Differences in Biomechanics Associated with Knee Osteoarthritis

Osteoarthritis of the knee is seen more frequently in females than males. However, few studies have examined the interplay of gender, gait mechanics, pain, and disability in persons with osteoarthritis. This study examines the influence of anthropometrics, radiographic disease severity, pain, and disability on gender differences in gait mechanics in patients with knee osteoarthritis. Gait mechanics for 26 men and 30 women were collected using 3-D kinematics and kinetics. Women had a significantly lower knee adduction moment than men and a significantly higher stride frequency. Within female subjects, variations in gait mechanics were primarily explained by weight, BMI, pain, and disability. In males, variations in gait mechanics were primarily explained by age and disability.