Scheduling internal audit activities: a stochastic combinatorial optimization problem

The problem of finding the optimal timing of audit activities within an organisation has been addressed by many researchers. We propose a stochastic programming formulation with Mixed Integer Linear Programming (MILP) and Constraint Programming (CP) certainty-equivalent models. In experiments neither approach dominates the other. However, the CP approach is orders of magnitude faster for large audit times, and almost as fast as the MILP approach for small audit times. This work generalises a previous approach by relaxing the assumption of instantaneous audits, and by prohibiting concurrent auditing.     

A neural network clustering model for miscellaneous components production planning

The growing importance of providing service to customers, e.g. post-sale assistance, supplying of spare parts, upgrading and integration of new elements in installed systems, enhances the importance of planning and management of upgrading parts in most manufacturing industries. These parts are generally characterized by high technical heterogeneity and have a highly variable and difficult to forecast demand. In some areas (especially the most dynamic, e.g. high-tech products), these kinds of components are quite common, and represent a very strong relation between the manufacturing firm and the market. These parts are generally too many to be efectively supported on a planning database system with individual records and too heterogeneous ( and sometimes with a too high value) to be supported all together in a single record. In this paper, we want to study the application of adaptive techniques for the clustering of these components in classes based on the similarities in their market behaviour in order to build an optimal database for planning production and supplying of these components.     

Decisions on placement and family preservation. Agreement and targeting

Vignettes presented to experts and workers in the child welfare field were used to explore the degree of agreement on decisions to place children in substitute care or to refer them to family preservation services. The design allowed for investigation of the problem of targeting in family preservation programs. Findings indicate considerable inconsistency in decisions among experts and workers, particularly in decisions to refer to family preservation and other in-home services. Contrary to the stated intentions of family preservation services, a majority of the referrals to these programs do not involve children who would have been placed in the absence of these programs.     

The dynamic stochastic topic block model for dynamic networks with textual edges

Statistics and Computing - The present paper develops a probabilistic model to cluster the nodes of a dynamic graph, accounting for the content of textual edges as well as their frequency. Vertices...     

White and black careers during the first decade of labor force experience. Part I: Occupational status

Retrospective life history data are used in this analysis of the processes which lead to differential levels of occupational success, using data collected from cohorts of black and white men, aged 30–39 in 1968.     

College Students' Perceptions of Professor/Instructor Bullying: Questionnaire Development and Psychometric Properties

Abstract

Objective: This study developed and examined the psychometric properties of a newly formed measure designed to assess professor/instructor bullying, as well as teacher bullying occurring prior to college. Additionally, prevalence of instructor bullying and characteristics related to victims of instructor bullying were examined. Participants: Participants were 337 college students recruited in 2012 from a northeastern university. Methods: An online questionnaire was administered to college students. A split-half, cross-validation approach was employed for measurement development. Results: The measure demonstrated strong criterion validity and internal consistency. Approximately half of students reported witnessing professor/instructor bullying and 18% reported being bullied by a professor/instructor. Report of teacher bullying occurring prior to college was related to professor/instructor bullying in college, and sex was a moderating variable. Conclusion: College students perceive instructor bullying as occurring but may not know how to properly address it. Prevention efforts should be made by university administrators, faculty, and staff.     

Using simulation to manage project supply chain in the offshore oil and gas industry

This paper is aimed at comparing simulation against spreadsheets as decision support tools to properly manage project supply chain in the offshore oil and gas industry. The paper presents a case study related to the problem of sizing a chain for pipeline laying from an offshore field in the Barents sea to the Russian coast. Results obtained through a spreadsheet developed by an oil and gas company have been compared to the ones gathered from an ad hoc simulation model. A simulation model with no stochastic variable has been introduced: results are quite similar to the ones of the spreadsheet, which allowed to validate the simulation model. However, the spreadsheet cannot take into account the continuous move of the pipe-lay vessel while laying the pipes and it does not consider stochastic variables whose effect in real life is not negligible. Both weaknesses above are discussed.