Uncertainty Analysis for Computer Model Projections of Hurricane Losses

Projecting losses associated with hurricanes is a complex and difficult undertaking that is wrought with uncertainties. Hurricane Charley, which struck southwest Florida on August 13, 2004, illustrates the uncertainty of forecasting damages from these storms. Due to shifts in the track and the rapid intensification of the storm, real-time estimates grew from 2 to 3 billion dollars in losses late on August 12 to a peak of 50 billion dollars for a brief time as the storm appeared to be headed for the Tampa Bay area. The storm hit the resort areas of Charlotte Harbor near Punta Gorda and then went on to Orlando in the central part of the state, with early poststorm estimates converging on a damage estimate in the 28 to 31 billion dollars range. Comparable damage to central Florida had not been seen since Hurricane Donna in 1960. The Florida Commission on Hurricane Loss Projection Methodology (FCHLPM) has recognized the role of computer models in projecting losses from hurricanes. The FCHLPM established a professional team to perform onsite (confidential) audits of computer models developed by several different companies in the United States that seek to have their models approved for use in insurance rate filings in Florida. The team's members represent the fields of actuarial science, computer science, meteorology, statistics, and wind and structural engineering. An important part of the auditing process requires uncertainty and sensitivity analyses to be performed with the applicant's proprietary model. To influence future such analyses, an uncertainty and sensitivity analysis has been completed for loss projections arising from use of a Holland B parameter hurricane wind field model. Uncertainty analysis quantifies the expected percentage reduction in the uncertainty of wind speed and loss that is attributable to each of the input variables.     

Cross‐Cultural Perspectives on Career Assessment

The authors present an overview of the discussion and presentations that took place concerning techniques and assessment in educational and vocational guidance at the recent symposium International Perspectives on Career Development. Two topics were examined. The 1st focused on the theoretical foundations of and psychometric issues in career assessment. The 2nd focused on the practice of career assessment and the use of career measures, particularly in cultural contexts for which the measures were not originally developed.     

MEANINGFUL REGRESSION AND ASSOCIATION MODELS FOR CLUSTERED ORDINAL DATA

Many proposed methods for analyzing clustered ordinal data focus on the regression model and consider the association structure within a cluster as a nuisance. However, the association structure is often of equal interest—for example, temporal association in longitudinal studies and association between responses to similar questions in a survey. We discuss the use, appropriateness, and interpretability of various latent variable and Markov models for the association structure and propose a new structure that exploits the ordinality of the response. The models are illustrated with a study concerning opinions regarding government spending and an analysis of stability and change in teenage marijuana use over time, where we reveal different behavioral patterns for boys and girls through a comprehensive investigation of individual response profiles.     

Understanding Unemployment Across California Counties

Unemployment rates differ widely and persistently across counties. This article examines equilibrium forces related to this geographic disparity with a focus on California. We show that although seasonal variation in employment can account for some of the differences, it cannot explain the total variation. Factors such as educational attainment, age, and gender appear to be strongly related to unemployment differences. Individuals living in higher‐unemployment areas also have a lower propensity to migrate. Because migration is usually considered to be the main equilibrating force, this evidence helps further explain why unemployment rates across counties are persistently different.     

'Making Culture Matter': Symbolic,Spatial and Social Boundaries between Uyghurs and Han Chinese

This article illustrates how Uyghurs in the 1990s defined and reinforced contemporary Uyghur national identity in relation to Xinjiang's growing Han Chinese population. Adopting Barth's theory of fluid and negotiable ethnic boundaries, it focuses on the notion of change. While Uyghurs are currently activating and exaggerating certain religio-cultural differences--in particular the avoidance of pork--as a means of ensuring symbolic, spatial and social segregation from the Han, those criteria did not prevent interaction to the same extent in the past; nor do they prevent Uyghurs from making concessions when it benefits them to do so. It is argued that it is not religio-cultural differences per se that lie at the root of increased tensions between Uyghurs and Han Chinese, but changing social, political and economic contexts: on the one hand, growing Uyghur perceptions of socio-economic inequalities between themselves and the Han (the 'internal factor') and, on the other, the vast changes within the international political arena since the late 1980s (the 'external factor').     

An exploratory study of gambling cross addictions

A growing body of empirical and theoretical research has concentrated on the overlaps and commonalities among chemical and non-chemical (behavioural) addictions. Pathological gambling has perhaps been the most widely researched behavioural addiction and some of this research has concerned the co-existing links between pathological gambling and alcohol/drug addiction in both the gambling substance abuser and the substance abusing gambler (i.e. cross addiction). This study was of an exploratory nature and attempted to gather information and data regarding gambling cross addictions in the UK. To achieve this, 456 letters were sent to all drug and alcohol helping agencies in England requesting such information. This yielded 210 returns (46% response rate). Results indicated that gambling cross addictions occur in both adults and adolescents and were almost exclusively a male condition. However, it must be noted only just over half of the responding agencies had encountered gambling cross addiction and reasons for this are speculated. Results also indicated the existence of various cross addicted subgroups including an adolescent subgroup who were addicted to fruit machines and abused solvents. Future research ideas are also discussed.A more detailed version of this paper is available from the author on request.     

Life with and without heart disease among women and men over 50

This article uses a demographic approach and data from the Health and Retirement Survey, a nationally representative sample of the U.S. population, to investigate sex differences in the length of life lived with heart disease and after a heart attack for persons in the United States age 50 and older. On average, women live longer than men with heart disease. At age 50 women can expect to live 7.9 years and men 6.7 years with heart disease. The average woman experiences heart disease onset three years older and heart attacks 4.4 years older than men.     

BATHTUB-TYPE CURVES IN RELIABILITY AND BEYOND

Finding optimal, or at least good, maintenance and repair policies is crucial in reliability engineering. Likewise, describing life phases of human mortality is important when determining social policy or insurance premiums. In these tasks, one searches for distributions to fit data and then makes inferences about the population(s). In the present paper, we focus on bathtub‐type distributions and provide a view of certain problems, methods and solutions, and a few challenges, that can be encountered in reliability engineering, survival analysis, demography and actuarial science.     

Stochastic Modelling of Times to Temperature for Furnaces Supplying Titanium Blooms to a Rolling Mill at TIMET

In conjunction with TIMET at Waunarlwydd (Swansea, UK) a model has been developed that will optimise the scheduling of various blooms to their eight furnaces so as to minimise the time taken to roll these blooms into the finished mill products. This production scheduling model requires reliable data on times taken for the various furnaces that heat the slabs and blooms to reach the temperatures required for rolling. These times to temperature are stochastic in nature and this paper identifies the distributional form for these times using the generalised F distribution as a modelling framework. The times to temperature were found to be similarly distributed over all furnaces. The identified distributional forms were incorporated into the scheduling model to optimise a particular campaign that was run at TIMET Swansea. Amongst other conclusion it was found that, compared to the actual campaign, the model produced a schedule that reduced the makespan by some 35%.