Optimal design of repetitive group sampling plans for Weibull and gamma distributions with applications and comparison to the Birnbaum–Saunders distribution

In this paper, we propose a multiple deferred state repetitive group sampling plan which is a new sampling plan developed by incorporating the features of both multiple deferred state sampling plan and repetitive group sampling plan, for assuring Weibull or gamma distributed mean life of the products. The quality of the product is represented by the ratio of true mean life and specified mean life of the products. Two points on the operating characteristic curve approach is used to determine the optimal parameters of the proposed plan. The plan parameters are determined by formulating an optimization problem for various combinations of producer's risk and consumer's risk for both distributions. The sensitivity analysis of the proposed plan is discussed. The implementation of the proposed plan is explained using real-life data and simulated data. The proposed plan under Weibull distribution is compared with the existing sampling plans. The average sample number (ASN) of the proposed plan and failure probability of the product are obtained under Weibull, gamma and Birnbaum–Saunders distributions for a specified value of shape parameter and compared with each other. In addition, a comparative study is made between the ASN of the proposed plan under Weibull and gamma distributions.     

On some consistent tests of mutual independence among several random vectors of arbitrary dimensions

Statistics and Computing - Testing for mutual independence among several random vectors is a challenging problem, and in recent years, it has gained significant attention in statistics and machine...     

Impact of customer loyalty and service operations on customer behaviour and firm performance: empirical evidence from UK retail sector

Abstract

Retail networks are striving to achieve competitive advantage by increasing value through loyalty and efficiency with a focus on service operations. As sales promotions have become an integral part of the retail supply chain planning, customer behavioural aspects based on loyalty and service operations have been challenged greatly. Subsequently, management capabilities, such as planning and timely replenishment, have become complicated tasks for many retail store managers. This study develops a model integrating retail network value and efficiencies with customer behaviour and performance. We validate the model using survey data from prominent U.K. retail store customers. Our data analysis shows that both loyalty and service operation attributes have positive significant impact on customer behaviour, while the service operation mediates the relationship between loyalty and customer behaviour. This result gives a new outlook to build managerial capability based on customer loyalty and service operations. Our results specifically show that the service operation attributes will indirectly influence the customers’ buying behaviour even in the presence of loyalty attribute such as promotion schemes. This result sends a strong signal to retail supply chain managers to offer customised promotions considering local community rather than having uniform sales promotion nationwide.     

Barriers to the Uptake of Emergency Accommodation by Young Runaways and Thrown‐out children and the Role of the ‘Transitional Person’

Young runaways and thrown‐out children, under‐16, face a number of barriers to accessing safe emergency accommodation. The need for such accommodation is not always apparent because children sometimes make themselves invisible to services through fear of being returned or fear of being removed from inappropriate accommodation. Young people's retrospective accounts of their experiences suggest the importance of a ‘transitional person’, an adult who has a pivotal role in trust‐building and who acts as a conduit to services and helps runaway and thrown‐out children overcome internal and external barriers to uptake of emergency accommodation.     

Cancer Screening Barriers for Community-based Older Hispanics and Caucasians

Despite advances in screening and early detection, ethnic minority populations, ages 65 and older, are less likely than Caucasians to participate in cancer screening services. Empirical research indicates that older ethnic minorities have cultural values that influence their behaviors. Addressing culturally relevant communication to better understand those values may increase participation in cancer screening. The study reported is a secondary analysis of qualitative data gathered from focus groups. Utilizing an interdisciplinary analytical lens, we compared older Hispanic and Caucasian's cultural values and their screening behaviors. Suggested psychosocial interventions are discussed to assist providers in their ongoing efforts to promote cancer screening.     

Mother‐to‐Child Transmission of HIV in China and the USA: A Comparative Analysis

This paper analyzes and compares the existing policies and programs for the prevention of mother‐to‐child transmission of HIV existing in China and in the USA. The implementation of these is still imperfect and there needs to be improvements in the education (the spreading of information) and in the general health care system of China. Particular attention will be drawn to the existing barriers to the effective implementation of prevention of mother‐to‐child‐transmission. The recommendations aim to solve similar barriers in both countries and some specifically dealing with problems in China. Since HIV infection in children is caused almost entirely by prenatal transmission, it is important that the governments, in partnership with civic society organizations, make all the necessary efforts to save the lives of their newborn citizens.     

On learning strategies for evolutionary Monte Carlo

The real-parameter evolutionary Monte Carlo algorithm (EMC) has been proposed as an effective tool both for sampling from high-dimensional distributions and for stochastic optimization (Liang and Wong, 2001). EMC uses a temperature ladder similar to that in parallel tempering (PT; Geyer, 1991). In contrast with PT, EMC allows for crossover moves between parallel and tempered MCMC chains. In the context of EMC, we introduce four new moves, which enhance its efficiency as measured by the effective sample size. Secondly, we introduce a practical strategy for determining the temperature range and placing the temperatures in the ladder used in EMC and PT. Lastly, we prove the validity of the conditional sampling step of the snooker algorithm, a crossover move in EMC, which extends a result of Roberts and Gilks (1994).     

Aligning supply chain collaboration using Analytic Hierarchy Process

The significance of collaboration among supply chain members has been sufficiently stressed in the recent literature as a powerful tool for increasing accuracy of demand forecasts and for consequent cost reductions. Since it has been recognized that naïve forecasting is no longer cost efficient, Supply Chain (SC) members have found it very important to exchange relevant information that will help improve accuracy of demand forecasting. This information differs widely in terms of their characteristics. For example, some information (e.g. historic sales data) that is cheap to exchange may not contribute to a great increase in forecast accuracy. Similarly, some information may not be very reliable (e.g. demand forecast by individual SC members). In general, there is a trade-off in the kind of information required and the kind of information exchanged. This study analyses these trade-offs using an Analytic Hierarchy Process (AHP) model. The model is then implemented based on case studies conducted in two manufacturing firms. The AHP model ranks available information in terms of their contributions to improve forecast accuracy, and can provide vital clues to SC partners for preparing exchangeable data. From the case studies using AHP model, it was proved that using the preferred SC data, the firms could enhance forecasts accuracy. This in turn can help the firms to make decisions on SC collaborative arrangements for information exchange.