An Arborescent Network Formulation and Dual Ascent Based Procedure for the Two-Stage Multi-Item Dynamic Demand Lotsize Problem

Traditional approaches for modeling and solving dynamic demand lotsize problems are based on Zangwill's single-source network and dynamic programming algorithms. In this paper, we propose an arborescent fixed-charge network (ARBNET) programming model and dual ascent based branch-and-bound procedure for the two-stage multi-item dynamic demand lotsize problem. Computational results show that the new approach is significantly more efficient than earlier solution strategies. The largest set of problems that could be solved using dynamic programming contained 4 end items and 12 time periods, and required 475.38 CPU seconds per problem. The dual ascent algorithms averaged .06 CPU seconds for this problem set, and problems with 30 end items and 24 time periods were solved in 85.65 CPU seconds. Similar results verify the superiority of the new approach for handling backlogged demand. An additional advantage of the algorithm is the availability of a feasible solution, with a known worst-case optimality gap, throughout the problem-solving process.     

On (Not) "Coloring in the Outline"

This article provides an overview and analysis of 10 studies on violence and injustice from the perspective of youth. These articles are contained in the issue of Journal of Social Issues entitled Youth Perspectives on Violence and Injustice and, in the articles, the authors offer a unique opportunity to go far beyond the current discursive terrains of youth and violence. Through a reinterpretation of what is conceptualized as normative, an expansion of the conceptualization of "youth" and an exploration of a broad range of topics, contexts and methods, the issue explores five provocative and significant critical themes. These themes are: methodology is critical; youth as subject, not object; gift and danger of a clinical approach; centrality of school? and at the intersection of social justice and development . The impact of popular culture on youth and violence and the importance of examining what adults value as "entertainment" are discussed also.     

Interpreting Parents Anonymous as a source of help for those with child abuse problems.

A study of reasons for joining the self-help group offers some considerations and guidelines for child welfare workers recommending this step to clients.     

Risk Analysis for Invasive Species: General Framework and Research Needs

A joint workshop was convened by the Society for Risk Analysis Ecological Risk Assessment Specialty Group and the Ecological Society of America Theoretical Ecology Section to provide independent scientific input into the formulation of methods and processes for risk assessment of invasive species. In breakout sessions on (1) the effects of invasive species on human health, (2) effects on plants and animals, (3) risk analysis issues and research needs related to entry and establishment of invasive species, and (4) risk analysis issues and research needs related to the spread and impacts of invasive species, workshop participants discussed an overall approach to risk assessment for invasive species. Workshop participants agreed on the need for empirical research on areas in which data are lacking, including potential invasive species, native species and habitats that may be impacted by invasive species, important biological processes and phenomena such as dispersal, and pathways of entry and spread for invasive species. Participants agreed that theoretical ecology can inform the process of risk assessment for invasive species by providing guidelines and conceptual models, and can contribute to improved decision making by providing a firm biological basis for risk assessments.     

Strengthening Supervision in Systems of Care: Exemplary Practices in Empirically Supported Treatments

The last few decades have witnessed major growth in the evidence base on effective client interventions used by social workers and other health and social service professionals. As the pressure for service agencies to offer empirically supported treatments has been increasing, financial and time constraints have driven a decline in the frequency and amount of supervision provided within many of these organizations. While the reduction in staff supervision presents a challenge for effective implementation of all treatments, there are comprehensive empirically supported treatment models for clients that serve as exemplars of supervisory practice through their explicit requirements, processes and tools for supervision and supervisor development. After a review of the current status of supervision nationally, an implementation science-based approach is described, which builds organizational support for supervision and promotes optimal supervisory practice through training and consultation of supervisors and supervisees. The elements of this comprehensive approach, developed by the Yale Program on Supervision, are detailed. Supervisory policies, practices, and tools created by the developers of empirically supported treatments and similarly grounded in the principles of implementation science are offered as further examples of strategies for ensuring effective supervision.