Bayes estimation of Moran–Downton bivariate exponential distribution based on censored samples

In this paper, we discuss a Bayesian estimation procedure for the parameters in a Moran–Downton bivariate exponential distribution based on complete and censored samples. A Markov-chain Monte Carlo method is used to obtain the Bayes estimates of the parameters. An intensive simulation experiment is conducted to study the performance of the proposed Bayesian estimation procedure. Discussions and suggestions are provided based on the simulation results. A numerical example is presented to illustrate the Bayesian estimation procedure developed here and some concluding remarks are provided.     

Modelling Poisson marked point processes using bivariate mixture transition distributions

A class of bivariate continuous-discrete distributions is proposed to fit Poisson dynamic models in a single unified framework via bivariate mixture transition distributions (BMTDs). Potential advantages of this class over the current models include its ability to capture stretches, bursts and nonlinear patterns characterized by Internet network traffic, high-frequency financial data and many others. It models the inter-arrival times and the number of arrivals (marks) in a single unified model which benefits from the dependence structure of the data. The continuous marginal distributions of this class include as special cases the exponential, gamma, Weibull and Rayleigh distributions (for the inter-arrival times), whereas the discrete marginal distributions are geometric and negative binomial. The conditional distributions are Poisson and Erlang. Maximum-likelihood estimation is discussed and parameter estimates are obtained using an expectation–maximization algorithm, while the standard errors are estimated using the missing information principle. It is shown via real data examples that the proposed BMTD models appear to capture data features better than other competing models.     

Improving communication via quantitative management

Villa Soft Drinks Ltd, established in 1884, manufactures and bottles spring waters and carbonates for both the growing adult soft drinks market and the more traditional soft drinks market. The company employs just over 100 people split between the manufacturing site in Sunderland and the head office and distribution centre in Washington. One of the fundamental problems affecting the day-to-day running of Villa, and most companies, is communication. There is a lack of awareness of the impact that changes in one department have on other departments (e.g. if production efficiency is increased by 10%, what impact will this have on warehousing?). Villa had recently identified key performance indicators (KPIs) to monitor all aspects of manufacturing performance on a regular basis. This enabled the current production situation to be evaluated and helped familiarize staff with charts and measurements. The use of Pareto analysis and problem solving techniques helped to boost efficiency and utilization. Key performance indicators were then developed in most other departments and are monitored and displayed regularly. The KPIs can be used further to improve transparency across the company by incorporating them in an interactive, interpretative tool to aid communication and understanding at all levels of the company. Individual departmental flow diagrams will be linked together to represent how the company operates. The diagrams will include both material flow and information flow. These data will then be organized in a software package and the end result will be a fully integrated simulation of the company in which any variable can be altered to demonstrate the effect this has on other departments and therefore the company as a whole. This will be an extremely valuable tool for the company as it will have many different applications, such as calculating manning requirements, identifying potential cycle time reductions and optimizing warehouse space.     

A distance-based diagnostic for trans-dimensional Markov chains

Over the last decade the use of trans-dimensional sampling algorithms has become endemic in the statistical literature. In spite of their application however, there are few reliable methods to assess whether the underlying Markov chains have reached their stationary distribution. In this article we present a distance-based method for the comparison of trans-dimensional Markov chain sample output for a broad class of models. This diagnostic will simultaneously assess deviations between and within chains. Illustration of the analysis of Markov chain sample-paths is presented in simulated examples and in two common modelling situations: a finite mixture analysis and a change-point problem.     

The effect of school resources on pupil attainment: a multilevel simultaneous equation modelling approach

Summary.  Improving educational achievement in UK schools is a priority, and of particular concern is the low achievement of specific groups, such as those from lower socio-economic backgrounds. An obvious question is whether we should be improving the outcomes of these pupils by spending more on their education. The literature on the effect of educational spending on the achievement of pupils has some methodological difficulties, in particular the endogeneity of school resource levels, and the intraschool correlations in pupils' responses. We adopt a multi-level simultaneous equation modelling approach to assess the effect of school resources on pupil attainment at age 14 years. The paper is the first to apply a simultaneous equation model to estimate the effect of school resources on pupils' achievement, using the newly available national pupil database and pupil level annual school census.     

The appropriation of American war memories: a critical juxtaposition of the Holocaust and the Vietnam War

This article delineates and critically juxtaposes the differential public commemorations of the Vietnam War and the Holocaust in the US. We elucidate how the tragedies of the Holocaust have been integrated into US public memory as a central part of the American story, solidifying the image of the United States as a powerful and moral nation that rescues desperate people from tyranny. In contrast, public commemorations of the highly divisive Vietnam War are sparse, if at all, in great part because they would re-ignite questions about the role of the US in Vietnam and in the suffering of its victims. While the Holocaust enables the United States to re-narrate national glory, the Vietnam War calls attention to US defeat and upsets the narrative of rescue and liberation. Through a critical juxtaposition of these two public memories, we assert that the moral and political divisiveness of the Vietnam War constitutes one unacknowledged source of the ascendancy and centrality of the Holocaust in American memory. Through our relational analysis of differential public memories, we draw on and contribute to the field of memory studies.     

A corrected likelihood method for the proportional hazards model with covariates subject to measurement error

There has been extensive interest in discussing inference methods for survival data when some covariates are subject to measurement error. It is known that standard inferential procedures produce biased estimation if measurement error is not taken into account. With the Cox proportional hazards model a number of methods have been proposed to correct bias induced by measurement error, where the attention centers on utilizing the partial likelihood function. It is also of interest to understand the impact on estimation of the baseline hazard function in settings with mismeasured covariates. In this paper we employ a weakly parametric form for the baseline hazard function and propose simple unbiased estimating functions for estimation of parameters. The proposed method is easy to implement and it reveals the connection between the naive method ignoring measurement error and the corrected method with measurement error accounted for. Simulation studies are carried out to evaluate the performance of the estimators as well as the impact of ignoring measurement error in covariates. As an illustration we apply the proposed methods to analyze a data set arising from the Busselton Health Study [Knuiman, M.W., Cullent, K.J., Bulsara, M.K., Welborn, T.A., Hobbs, M.S.T., 1994. Mortality trends, 1965 to 1989, in Busselton, the site of repeated health surveys and interventions. Austral. J. Public Health 18, 129–135].     

Unravelling the Subsidiary Initiative Process: A Multilevel Approach

Strategy‐making and entrepreneurial behaviour at the subsidiary level, in particular the phenomenon of subsidiary initiative, has received increasing research attention in recent years. In the fields of international business, strategy and entrepreneurship, several studies addressing aspects of this phenomenon have been conducted. They focused on different stages of the subsidiary initiative process, different theories and also different methodological levels. This puts subsidiary initiatives as a topic at the crossroads of several disciplines, so that theory‐building remains fragmented, and there is a lack of perspective capturing the complexity of the entire subsidiary initiative process. Based on a comprehensive literature review, this paper discusses theoretical concepts and streams of thinking that have contributed to our understanding of the subsidiary initiative process, and develops an organizing framework based on stages and levels of the subsidiary initiative process. In order to integrate theories across levels, the authors identify ‘aggregation’ theories that guide the emergence of initiatives from the individual up to the network level, and also acknowledge theories that link the micro–macro divide and may help in the development of a more holistic view of subsidiary initiatives.     

Countertransference risks when women treat women

Certain female patients deal with issues of sexuality, reproduction, aggression, and dependence in ways which may generate intense reactions in their female therapists. We will describe the range of responses we experienced while treating various women in an acute psychiatric inpatient setting. A surprising finding was that not only our problematic responses, but also our effective solutions, have often occurred unconsciously.A shorter version of this paper was presented at the California Chapter NASW Conference on April 7, 1989.