Output-sensitive algorithms for Tukey depth and related problems

The Tukey depth (Proceedings of the International Congress of Mathematicians, vol. 2, pp. 523–531, 1975) of a point p with respect to a finite set S of points is the minimum number of elements of S contained in any closed halfspace that contains p. Algorithms for computing the Tukey depth of a point in various dimensions are considered. The running times of these algorithms depend on the value of the output, making them suited to situations, such as outlier removal, where the value of the output is typically small. This research was partly funded by the NSERC Canada.     

Writing a Book Review for JFSW

ABSTRACT

For children in foster care, continued contact with biological parents may have significant implications. This article seeks to synthesize literature examining attachment theory and visitation between children in foster care and their parents. The results of the research synthesis indicate that although the exploration of attachment theory began over 40 years ago, the questions regarding the implications of foster care visitation and attachment continuation surprisingly remain unanswered.     

Sex-Role Stereotyping and Social Work Education

The article presents the results of a nationwide study that examined the written criteria that is currently being used by graduate schools of social work for the appointment, retention, and promotion of their faculties. A content analysis of the study is discussed, and a unique behavioral model for the evaluation of faculty competence is offered.     

Probabilistic Assessment of the Failure Risk of the Europa Clipper Spacecraft due to Radiations

The Europa mission approved in 2019 is still in the development phase. It is designed to conduct a detailed reconnaissance of that moon of Jupiter as it could possibly support life as we know it. This article is based on a top-down approach (mission → system → subsystems → components) to model the probability of mission failure. The focus here is on the case where the (uncertain) radiation load exceeds the (uncertain) capacity of critical subsystems of the spacecraft. The model is an illustrative quantification of the uncertainties about (1) the complex external radiation environment in repeated exposures, (2) the effectiveness of the shielding in different zones of the spacecraft, and (3) the components’ capacities, by modeling all three as dynamic random variables. A simulation including a sensitivity analysis is used to obtain the failure probability of the whole mission in forty-five revolutions around Jupiter. This article illustrates how probabilistic risk analysis based on engineering models, test results and expert opinions can be used in the early stages of the design of space missions when uncertainties are large. It also describes the optimization of the spacecraft design, taking into account the decisionmakers’ risk attitude and the mission resource constraints.     

Preface

No abstract available for this article.     

Dialogue and Challenge: Involving Service Users and Carers in Small Group Learning with Social Work and Nursing Students

This paper examines the rationale for service user and carer involvement in professional education and reflects on an initiative in which social work and nursing students undertook a sequence of joint learning in relation to mental health theory and practice. Central to this initiative was the promotion of opportunities for dialogue, both between students from different professional disciplines and between students, service users and carers. To enable this, much of the learning took place in small groups facilitated by either a service user or a carer.

Evaluation of this initiative indicated that, for the majority of social work and nursing students, learning from this shared experience had a major impact on their professional development. However, a small but significant minority found it hard to enter into a dialogue with others on a basis of equality and a sharing of their human as well as their professional experience. Some students indicated that they would have preferred a focus on acquiring more specialist professional knowledge and skills. This raises important issues in relation to the changing expectations of professionalism and professional education—and what really makes someone ‘fit for practice’.     

Coverage with k-transmitters in the presence of obstacles

For a fixed integer k≥0, a k-transmitter is an omnidirectional wireless transmitter with an infinite broadcast range that is able to penetrate up to k “walls”, represented as line segments in the plane. We develop lower and upper bounds for the number of k-transmitters that are necessary and sufficient to cover a given collection of line segments, polygonal chains and polygons.