Approximations to the powers of the likelihood ratio tests: the loop ordering and slippage alternatives

Approximations to the power functions of the likelihood ratio tests of homogeneity of normal means against the simple loop ordering at slippage alternatives are considered. If a researcher knows which mean is smallest and which is largest, but does not know how the other means are ordered, then a simple loop ordering is appropriate. The accuracy of the several moment approximations are studied for the case of known variances and it is found that for powers in the range typically of interest, the two-moment approximation seems quite adequate. Approximations based on mixtures of noncentral F variables are developed for the case of unknown variances. The critical values of the test statistics are also tabulated for selected levels of significance.     

Optimum stratification for allocation proportional to strata totals for simple random sampling scheme

The paper considers the problem of finding optimum strata boundaries when sample sizes to different strata are allocated in proportion to the strata totals of the auxiliary variable. This variable is also treated as the stratification variable. Minimal equations, solutions to which provide the optimum boundaries, have been obtained. Because of the implicit nature of these equations their exact solutions cannot be obtained. Therefore, methods of obtaining their approximate solutions have been presented. A lim¬iting expression for the variance of the estimate of population mean, as the number of strata tend to become large, has also been obtained.     

On the adoption of lean manufacturing principles in process industries

Traditionally, the lean paradigm has been applied to discrete manufacturing of items that can be easily put together and taken apart. The process industry, on the other hand, transforms raw materials into cohesive units that are basically blended into a final product with parts that cannot be disassembled and then reassembled. The current lean literature provides numerous commendable examples of theory and practices of lean principles in discrete manufacturing. However, its application in process industry is limited. Furthermore, there is no systematic accounting of the lean literature in this sector, which may have contributed to lesser awareness in the industry. This paper provides a state-of-the-art review of lean manufacturing literature with respect to its applications in process industry. It contributes to the classification of literature in a manner which helps to identify strategies suitable for the adoption of lean concepts in process industry. The paper seeks to synthesise the literature with an emphasis on identifying the scope for lean in process industry and associated benefits. The review also presents an analysis of the lean tools and techniques that have been applied or have potential application in the process industry and the challenges to implement lean. We believe that such a comprehensive review will not only facilitate the adoption of lean in process industry but will also provide agenda for further research by exposing voids in the knowledge base.     

A Virtual Field Practicum: Building Core Competencies Prior to Agency Placement

ABSTRACT

Providing effective services to clients with increasingly severe challenges in an era of fiscal constraints calls for schools of social work to assume greater responsibility for preparing interns for clinical practice. This article describes a virtual field practicum (VFP), an online skill-building experience designed to meet this need and reports preliminary findings. The VFP employs client simulation and other experiential activities; its intent is to foster student acquisition of core competencies prior to agency placement. Longitudinal data were collected on VFP students and their traditional counterparts across 4 semesters. Results show that VFP students performed as well, if not slightly better, on competency measures than traditional students, suggesting that this model is a viable option for educators to consider.     

Bayesian inference using product of spacings function for Progressive hybrid Type-I censoring scheme

This article is devoted to the development of product of spacings estimator for a Progressive hybrid Type-I censoring scheme with binomial removals. The experimental units are assumed to follow inverse Lindley distribution. We propose a Bayes estimator of associated scale parameter based on the product of spacings function and simultaneously compare it with that obtained under a usual Bayesian estimation procedure. The estimators are obtained under the squared error loss function along with corresponding HP intervals evaluated by using the Markov chain Monte-Carlo technique. The classical product of spacings estimator has also been derived and compared with the maximum likelihood estimator in addition to 95% average asymptotic confidence intervals. The applicability of the proposed methods is demonstrated by analysing a real data of guinea pigs affected with tuberculosis for the considered censoring scheme.     

Force steadiness in the lower extremities as an independent predictor of functional performance in older women

The relationship between isometric force control and functional performance is unknown. Submaximal steadiness and accuracy were measured during a constant force-matching task at 50% of maximal isometric voluntary contraction (MVC) of the knee extensors in 19 older women (70-89 years). Other variables included MVC, rate of torque development, and EMG activity. Functional performance was assessed during maximal performance of walking endurance, chair rising, and stair climbing. Isometric steadiness (but not accuracy) was found to independently predict chair-rise time and stair-climbing power and explained more variance in these tasks than any other variable. Walking endurance was related to muscle strength but not steadiness. These results suggest that steadiness is an independent predictor of brief, stressful functional-performance tasks in older women with mild functional impairment. Thus, improving steadiness might help reduce functional limitations or disability in older adults.     

Efficient Job Scheduling Algorithms with Multi-Type Contentions

In this paper, we consider an interesting generalization of the classic job scheduling problem in which each job needs to compete not only for machines but also for other types of resources. The contentions among jobs for machines and for resources could interfere with each other, which complicates the problem dramatically. We present a family of approximation algorithms for solving several variants of the problem by using a generic algorithmic framework. Our algorithms achieve a constant approximation ratio (i.e., 3) when there is only one type of resources or certain dependency relation exists among multiple types of resources. When the r resources are unrelated, the approximation ratio of our algorithm becomes k+2, where k≤ r is a constant depending on the problem instance. As an application, we also show that our techniques can be easily applied to optical burst switching (OBS) networks to design more efficient wavelength scheduling algorithms.This research was supported in part by an IBM faculty partnership award, and an IRCAF award from SUNY Buffalo.