Model selection consistency of U-statistics with convex loss and weighted lasso penalty

In the paper we consider minimisation of U-statistics with the weighted Lasso penalty and investigate their asymptotic properties in model selection and estimation. We prove that the use of appropriate weights in the penalty leads to the procedure that behaves like the oracle that knows the true model in advance, i.e. it is model selection consistent and estimates nonzero parameters with the standard rate. For the unweighted Lasso penalty, we obtain sufficient and necessary conditions for model selection consistency of estimators. The obtained results strongly based on the convexity of the loss function that is the main assumption of the paper. Our theorems can be applied to the ranking problem as well as generalised regression models. Thus, using U-statistics we can study more complex models (better describing real problems) than usually investigated linear or generalised linear models.     

Trajectory of problem behaviours of Korean adopted children: using piecewise hierarchical linear growth modelling

This study examined the trajectory of problem behaviours in domestically adopted children in South Korea as they aged. This study used the Panel Study on Korean Adopted Children's longitudinal, three‐wave data (2006, 2008 and 2010). Although data were collected at three time points, our data consisted of six time points, which covered the 5–10 years age range of the adopted children at the time of survey. One hundred sixty‐four children were included in the analysis, 75 of whom contributed to one time point, 74 to two time points and 15 to three time points. The trajectory of the problem behaviours of adopted children was examined using a piecewise hierarchical linear growth model. Because the initial exploration of the data suggested non‐linear changes in behaviour problems over time, we split the growth trajectory into two time periods: Time 1 (5–7 years) and Time 2 (7–10 years). A two‐rate model was used to estimate separate slopes for the two time periods. Results showed that the externalizing and internalizing problems of adopted children have different trajectories. Internalizing problems did not show significant changes after 5 years of age, while externalizing problems increased until 7 years of age and decreased significantly thereafter.     

‘Let's Talk About Children’: Investigating the Use of a Family‐focused Intervention in the Gambling Support Services Sector

The family‐focused mental health intervention, ‘Let's Talk About Children,’ has positively influenced the lives of families affected by parental mental illness. This paper outlines the use of this brief, strengths‐based intervention for parents with gambling and other co‐occurring issues from the gamblers’ support services sector. Over a six‐month period, a training manual and accompanying resources were adapted for the gamblers’ support services sector and a targeted training session developed. Nine problem gambling counsellors from three Victorian gambling support services trialled the Let's Talk About Children intervention over a four‐month period. Qualitative data were gathered through focus groups, interviews, and practice enquiry groups to determine the impact of the Let's Talk About Children model for gambling support services. The results are presented as ‘practice wisdoms and recommendations’ reporting on the impact of the trial and to provide some guidance to support others in the implementation of a specific family‐focused intervention. This paper reports on the first exploratory trial of Let's Talk About Children for the gambler's support services sector in Australia.     

Likelihood procedure for testing changes in skew normal model with applications to stock returns

The skew normal distribution family is an attractive distribution family due to its mathematical tractability and inclusion of the normal distribution as the special case. It has wide applications in many applied fields such as finance, economics, and medical research. Such a distribution family has been studied extensively since it was introduced by Azzalini in 1985 Azzalini, A. (1985). A class of distributions which includes the normal ones. Scandinavian Journal of Statistics 12:171–178. [Google Scholar] for the first time. Yet, few work has been done on the study of change point problem related to this distribution family. In this article, we propose the likelihood ratio test (LRT) to detect changes in the parameters of the skew normal distribution associated with some asymptotic results of the test statistic. Simulations have been conducted under different scenarios to investigate the performance of the proposed method. Comparisons to some other existing method indicate the comparable power of the method in detecting changes in parameters of the skew normal distribution model. Applications on two real data: Brazilian and Tanzanian stock returns illustrate the detection procedure.     

An upper bound on the minimal total cost of the transportation problem with varying demands and supplies

In general cases, to find the exact upper bound on the minimal total cost of the transportation problem with varying demands and supplies is an NP-hard problem. In literature, there are only two approaches with several shortcomings to solve the problem. In this paper, the problem is formulated as a bi-level programming model, and proven to be solvable in a polynomial time if the sum of the lower bounds for all the supplies is no less than the sum of the upper bounds for all the demands; and a heuristic algorithm named TPVDS-A based on genetic algorithm is developed as an efficient and robust solution method of the model. Computational experiments on benchmark and new randomly generated instances show that the TPVDS-A algorithm outperforms the two existing approaches.     

A shelf-space optimization model when demand is stochastic and space-elastic

The more customer demand is impulse-driven, the more it is space-dependent and the more it is subject to variation. We investigate the corresponding problem of retail shelf-space planning when demand is stochastic and sensitive to the number and position of facings. We develop a model to maximize a retailer׳s profit by selecting the number of facings and their shelf position under the assumption of limited space. The model is particularly applicable to promotional or temporary products.We develop the first optimization model and solution approach that takes stochastic demand into account, since the current literature applies deterministic models for shelf-space planning. By the means of an innovative modeling approach for the case with space- and positioning effects and the conversion of our problem into a mixed-integer problem, we obtain optimal results within very short run times for large-scale instances relevant in practice. Furthermore, we develop a solution approach to account for cross-space elasticity, and solve it using an own heuristic, which efficiently yields near-optimal results. We demonstrate that correctly considering space elasticity and demand variation is essential. The corresponding impacts on profits and solution structures become even more significant when space elasticity and stochastic demand interact, resulting in up to 5% higher profits and up to 80% differences in solution structures, if both effects are correctly accounted for. We develop an efficient modeling approach, compare the model results with approaches applied in practice and derive rules-of-thumb for planners.     

What mental health professionals in Israel know and think about adolescent problem gambling

Mental health professionals are well versed in addressing multiple adolescent risky behaviours and play a primary role in the identification of and referral process and service provision for young people who engage in such behaviours. Given their ‘person-in-environment’ approach, training in multi-sectoral collaboration, and awareness of social policies, social workers are especially equipped to provide needed mental health services to young people. The aim of the current study was to examine Israeli mental health professionals’ awareness of and attitudes towards adolescent high-risk behaviours, including gambling. Child psychologists, social workers and school counsellors (N = 273) completed an online survey addressing concerns related to high-risk behaviours. Findings revealed that social workers perceived gambling as being among one of the least concerning adolescent mental health issues and reported feeling the least confident in their abilities to provide services to young people with gambling problems. The results suggest the importance of youth gambling addictions being incorporated into social work training curricula.     

社会工作专业教学组织机制：问题与选择

优化教学组织机制是提高社会工作专业教育质量不可或缺的重要一环。面对社会工作专业课堂教学和实践教学他组织与自组织相分离的现实困境,教师要科学选择介入策略,勇于革新教学方法,以实现教学组织机制的优化。     

一类弹性系统的内部精确能控性

该文考虑的是具有分布控制的Timoshenko梁系统的精确能控性.用谱分解方法建立了保守系统的正反向能量不等式,证明了在通常的能量空间中该系统是精确能控的.