The influence of load on the lifetime distribution

This paper derives lifetime distributions for components that fail due to overloading. We introduce the notion of energy similarity. This makes it possible to use knowledge about how components behave under different loads in order to establish a probability model. To obtain parametric families, we consider two physically distinct cases: (1) components that function individually and (2) components that function as part of a system. The former leads to univariate and the latter to multivariate models. The results are particularly useful when little or no data is available.     

Childhood abuse and neglect in severely dependent female addicts: homogeneity and reliability of a Swedish version of the Childhood Trauma Questionnaire

This study explores the psychometric characteristics of childhood experiences ('Barndomsupplevelser'), using a Swedish translation of the 53–item version of the Childhood Trauma Questionnaire (CTQ). Fifty–five female addicts, treated in a compulsory–care setting, completed the questionnaire. Homogeneity and reliability were studied using principal component analyses (PCA) and Cronbach's alpha. The test was submitted to content analysis. Nearly all (94.5%) had experienced childhood abuse or neglect. The internal consistency is high. The 4–factor solution corresponded to the subscales of emotional and physical abuse (combined), of sexual abuse and of emotional neglect, while the items in the physical neglect subscale were distributed to several factors. In the 5–factor solution, this subscale was divided into two factors. Content analyses of these factors point to other meanings than physical neglect. The CTQ (Swedish translation) was found to have high consistency and homogeneity in four of the five subscales (emotional, physical and sexual abuse, and emotional neglect), while the subscale on physical neglect may need revision. The new 28–item brief version seems to be an improvement, with regard to these problems.     

The Mediation Window: Regulation of Argumentation and Affect in Custody Mediation

High-conflict custody mediation requires working with both the emotional and the factual aspects of the conflict, while balancing unequal power relations between parents. Applying conversation analysis methods to a case of “treatment as usual” high-conflict mediation, this study offers an analysis of the process of establishing a balance point—the mediation window—where both emotional and practical concerns can be discussed efficiently. Communication patterns in the selected case are compared to an extract of the remaining corpus from which it is drawn, consisting of 38 high-conflict mediation cases. Findings are discussed with respect to the practice and ideology of custody mediation, particularly concerning empowerment, self-determination, and mediator control.     

Efficient frontiers for electricity procurement by an LDC with multiple purchase options

In meeting its retail sales obligations, management of a local distribution company (LDC) must determine the extent to which it should rely on spot markets, forward contracts, and the increasingly popular long-term tolling agreements under which it pays a fee to reserve generator capacity. We address these issues by solving a mathematical programming model to derive the efficient frontier that summarizes the optimal tradeoffs available to the LDC between procurement risk and expected cost. To illustrate the approach, we estimate the expected procurement costs and associated variances that proxy for risk through a spot-price regression for the spot-purchase alternative and a variable-cost regression for the tolling-agreement alternative. The estimated regressions yield the estimates required to determine the efficient frontier. We develop several such frontiers under alternative assumptions as to the forward-contract price and the tolling agreement's capacity payment, and discuss the implications of our results for LDC management.     

Towards next-generation visual archives: image,film and discourse

The digital turn in visual studies has played a major role in the terminological overlap between ‘archive’, ‘database’ and ‘corpus’, and it has brought about a number of positive developments such as improved accessibility and availability. At the same time, it has also raised important questions pertaining to the materiality, searchability, annotation and analysis of the data at hand. Through a series of theoretical constructs and empirical examples, this paper illustrates the necessity and benefits of interdisciplinary dialogue when tackling the multimodal corpus annotation challenge. The meaningful interrelations between semiotic modes, the combinations between manual and (semi)automated annotation, the seamless integration of coding and annotation schemes which share common logics and the contextual embedding of the presented analyses strongly suggest multimodal document analysis in all its forms will continuously benefit from a corpus-based approach.     

Optimal design for epidemiological studies subject to designed missingness

In large epidemiological studies, budgetary or logistical constraints will typically preclude study investigators from measuring all exposures, covariates and outcomes of interest on all study subjects. We develop a flexible theoretical framework that incorporates a number of familiar designs such as case control and cohort studies, as well as multistage sampling designs. Our framework also allows for designed missingness and includes the option for outcome dependent designs. Our formulation is based on maximum likelihood and generalizes well known results for inference with missing data to the multistage setting. A variety of techniques are applied to streamline the computation of the Hessian matrix for these designs, facilitating the development of an efficient software tool to implement a wide variety of designs.