Defense Resource Distribution Between Protection and Redundancy for Constant Resource Stockpiling Pace

The article considers the optimal resource distribution in a parallel system between increasing protection and providing redundancy in a situation when the attacker's and defender's resources are stockpiling and the resource increment rate is constant. It is assumed that the system must perform within an exogenously given time horizon and the attack time probability is uniformly distributed along this horizon. The defender optimizes the resource distribution in order to minimize the system destruction probability during the time horizon. First, we find the optimal pace of construction of the new redundant elements assuming that the construction must start in the initial stage of the stockpiling process. We show that starting construction of new elements in the beginning of the system's existence results in its high initial vulnerability. Introducing the time delay before starting the construction can reduce the initial system vulnerability and the entire system destruction probability. The problem of optimization of time delay and new element construction pace is considered with and without constraint on the initial system vulnerability. Examples illustrating the methodology of the optimal defense strategy analysis are presented.     

Learning difficulties and academic competence among children in contact with the child welfare system

Children who have been in the welfare system tend to have poor social and health outcomes as adults. The aim of this study was to examine learning difficulties, as well as academic competence, among children in contact with child welfare service, and to compare this group to their same‐age peers. The material consisted of 4114 children in fifth to seventh grade, of which 101 were in contact with child welfare services. Information on learning difficulties and academic competence was obtained through questionnaires to teacher and parent/caregivers. As expected, there were significantly more children with learning difficulties in the child welfare group than the peer group; 12% of child welfare clients had general learning difficulties compared to only 0.4% of their peers, and 31% had specific learning difficulties in relation to mathematics and/or reading and writing, compared to 10% of their peers. The majority of child welfare children received assistance from pedagogical–psychological services. While more than every second child welfare client without general learning disability had low academic competence, there were also 15% who had high academic competence. The results show that although many of the children in contact with child welfare service have learning difficulties, there is also heterogeneity and potential for academic achievement.     

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.     

Complainers and noncomplainers revisited: Another look at the data

The point of departure for the present article is previous attempts to profile complaining, dissatisfied consumers. By reviewing the previous literature, three “models” were identified: the “resource”, the “learning” and the “personality” model respectivey. An empirical test of the three models reveals only modest differences between complaining and noncomplaining consumers. Marketplace participation was found to be the most meaningful explanatory factor.     

Using the bootstrap in correlation analysis,with application to a longitudinal data set

The problem of constructing simultaneous confidence intervals for various measures of association is considered. Alternative bootstrap algorithms are given for approximating the sampling distributions of the quantities generating the confidence sets. The small sample performance of the procedures is illustrated using simulated data from 3- and 6-variate normal populations. The results are applied to a large multidimensional longitudinal data set from a study of the relationship between drug use and several behavioral attributes.     

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.