Rose Ray

• PhD
• Principal Investigator at Exponent

Accelerated testing is a set of methods that attempts to replicate and predict the quantitative effect on product life of what are assumed to be the most important degradation mechanisms determining product life in actual service. In all accelerated testing approaches, one or more physical degradation methods are applied to promote failure. The his...

The hazard function is a tool for describing the process of time to failure. Hazard functions arise in the context of survival analysis, also known as failure analysis , and provide a convenient way to visualize how the risk of failure changes with age or time. The exponential, Weibull, and lognormal distribution are three of the commonly used stat...

Three years of data from the Large Truck Crash Causation Study (LTCCS) were analyzed to identify accidents involving heavy trucks (GVWR >10,000 lbs.). Risk of rollover and ejection was determined as well as belt usage rates. Risk of ejection was also analyzed based on rollover status and belt use. The Abbreviated Injury Scale (AIS) was used as an i...

To prevent wheel lock up (and possible loss of control and capsize) during hard braking motorcycle manufacturers have equipped motorcycles with Antilock Brake Systems (ABS) either as an option or as standard equipment. Several studies utilizing real-world crash data have been published which estimate the effectiveness of motorcycle ABS in reducing...

This paper explores tire placement with given tread depths on vehicles from two distinct perspectives. The first area explored is an analysis of crash data recently reported by the National Highway Traffic Safety Administration (NHTSA). In this report, thousands of tire-related crashes were investigated where the tread depth and inflation pressure...

Inadvertent vehicle movement incidents, in which a vehicle rolls away after the driver has exited, may occur in automatic transmission vehicles as a result of environmental, vehicular, and/or driver factors. Some explanations have focused on claimed potential malfunctions or design flaws in the vehicle s console shift mechanism or in the automatic...

Police accident reports (PARs) of motor vehicle collisions typically include information regarding occupant restraint use. It has been suggested that PARs overestimate restraint use. Previous studies comparing PAR restraint usage with that determined during a NASS/CDS in-depth investigation found agreement in approximately 90% of cases. The accurac...

The process of design inherently involves consideration of risk trade offs; intervening to reduce one risk often increases another. In addition to creating a design for the intended function of the product, a rational process of risk management involves prediction of risk through design analysis, statistical evaluation of the history of similar pro...

Competing‐risk models are used to examine the relationship between different risk factors to study different types of failures that may occur in the same population. What would happen to the remaining risks if one or more causes of failure could be eliminated is a question that may be addressed with these models under some conditions. Competing ris...

Accelerated testing is a set of methods that attempts to replicate and predict the quantitative effect on product life of what are assumed to be the most important degradation mechanisms determining product life in actual service. In all accelerated testing approaches, one or more physical degradation methods are applied to promote failure. The his...

Comparative risk assessment is an analytic process of evaluating and ranking the different factors that contribute to a particular outcome, such as human disease. The term comparative risk assessment is most frequently used in the context of environmental risk, but the principles and methodology are applicable in other contexts. Comparative risk as...

The hazard function is a tool for describing the process of time to failure. Hazard functions arise in the context of survival analysis, also known as failure analysis , and provide a convenient way to visualize how the risk of failure changes with age or time. The exponential, Weibull, and lognormal distribution are three of the commonly used stat...

Published reports postulate the existence of an electrical injury syndrome or pattern whereby clinical and physical manifestations of a shock injury occur remote to the actual current pathway, and may present in the absence of related acute findings. It is suggested that the extent of such injury is unrelated to the magnitude of shock current and t...

Fires originating in large trucks can be significant in terms of both the potential for personal injury or death and the potential for substantial economic loss of the vehicle and its cargo. This analysis examines the large trucks involved in fire incidents and the causes of the fires by examining the National Automotive Sampling System (NASS/GES),...

We applied the principles of visual perception, light, and optics to quantify the influence of ambient sunlight on the ability of skiers and snowboarders to perceive ground contours on a ski slope. To this end, we systematically measured the visibility of the terrain on ski runs under a variety of lighting conditions at Mammoth Mountain In Californ...

The potential human health risks associated with consuming fish containing hazardous substances are related to the frequency, duration, and magnitude of exposure. Because these risk factors are often site specific, they require site-specific data. In anticipation of performing a risk assessment of the lower 6 miles of the Passaic River in New Jerse...

This article describes a unique analytical method employed to characterize angler activities on the lower 6-mile stretch of the Passaic River in New Jersey. The method used data collected by a creel/angler survey that was designed to capture the information necessary to calculate the exposure factors needed to characterize the fish consumption path...

The results of an analysis of site-specific creel and angler information collected for the lower 6 miles of the Passaic River in Newark, NJ (Study Area), demonstrate that performing a site-specific creel/angler survey was essential to capture the unique characteristics of the anglers using the Study Area. The results presented were developed using...

Weibull analysis is a powerful predictive tool for studying failure trends of engineering systems. [1] One noted shortcoming is that traditional techniques require the size of the susceptible population to be known. The method described in this paper allows for estimation of the size of the susceptible population using only failure data and no assu...

Despite more than 20 years of surveillance and epidemiologic studies using the beryllium blood lymphocyte proliferation test (BeBLPT) as a measure of beryllium sensitization (BeS) and as an aid for diagnosing subclinical chronic beryllium disease (CBD), improvements in specific understanding of the inhalation toxicology of CBD have been limited. Al...

Recently there has been increasing interest in stationary vehicle fires (SVF) and the safety of vehicles parked in garages. This interest has grown out of allegations by insurance companies that garage fires, some of which spread to other parts of the residence and cause considerable damage and/or injuries, may be caused by vehicles, and hence the...

Both state police and the National Automotive Sampling System/Crashworthiness Data System (NASS/CDS) keep automotive collision statistics to varying levels of detail. Some of these details (e.g., collision relative velocity and driver height and weight) are reported in the NASS/CDS, but not in state databases. This article explores whether these de...

To examine existing asbestos-exposed occupational cohorts and apply a meta-analytic technique to determine the magnitude of association between exposure and lung cancer and to investigate other cancer sites that may be related to such an exposure. We summarized the data from 69 asbestos-exposed occupational cohorts reporting on cancer morbidity and...

In this report, we evaluate a modified version of Eidt ’s (1973) field-based phosphate analysis technique to explore its validity. Soil samples were collected and analysed from an archaeological site in the Sunol Valley, Alameda County, California. Four characteristics were recorded for all soil samples. To evaluate the technique statistically, a r...

A new form of regression is applied to the problem of modeling the flow of water and contaminants through soil. In a fashion analogous to nested ANOVA, the new method parametrizes global distributional structure separately from local structure. A blind study is conducted to assess the precision of mixing parameter estimation as a function of depth....

Large prospective studies and intervention trials have identified major risk factors for premature heart disease in men, while the Framingham Heart Disease Study has provided the leading evidence of predictors of cardiovascular disease in women. We evaluated the role of these risk factors in a 13-year follow-up study of 8935 premenopausal and 2716...

The joint effects of conjugated estrogen use, age, body mass index, and smoking on plasma lipid and lipoprotein levels were assessed in 585 women who used oral estrogen and 1093 women who did not who participated in the Walnut Creek Contraceptive Drug Study. Whether administered daily or cyclically, conjugated estrogen was associated with reduction...

593 women from a cohort of 8,652 healthy women failed a 1-hr glucose screening test. These 593 women with suspected glucose intolerance were classified as normal or as having impaired glucose tolerance (IGT) or diabetes mellitus (DM) after an oral standard glucose tolerance test (SGTT) and were followed over a mean 8.55 years. No permanent change i...

Chlamydia trachomatis is commonly found in the urethra of men with gonococcal urethritis. Studies report a 20%-40% rate of double infection. A two-year study of men attending a venereal disease clinic in California showed that only 4% (4/99) or 7% (10/147) of men with gonorrhea had concomitant chlamydial infection, whereas 25-31% of the men with no...

We tested 383 women with and 500 women without cervical neoplasia for antibodies against Chlamydia trachomatis or herpes simplex virus (HSV). Exposure to both agents was related to sexual activity, with the highest prevalence of antibodies found in women with more sex partners and who had first coitus at an earlier age. When subjects were matched f...

The aim of this prospective study was to assess the noncontraceptive effects of oral contraceptives (OCs) by comparing biochemical and physiologic measurements and the incidence of disease in users and nonusers of these drugs. This report compares the rates of disease occurrence leading to hospitalization or death in these two groups.

Analytic ultracentrifugation of serum lipoproteins from 80 men and 54 women aged 27--66 was used to determine if specific segments of the high density (HDL), low density (LDL) and very low density (VLDL) lipoprotein schlieren curves could be defined so as to reveal significant correlations among them. Differences in correlations resulted in divisio...

The present paper addressed the continued misinterpretation and misapplication of linear discriminant function analysis in neuropsychological research. Methodological problems concerning the influence of shrinkage and stepwise selection procedures on LDFA are virtually ignored and affect both the classification and inferential application of LDFA....

Perttz, E., S. Ramcharan (Kaiser-Permanente Medical Center, Walnut Creek, CA 94596), J. Frank, W. L. Brown, S. Huang and R. Ray. The incidence of cervical cancer and duration of oral contraceptive use. Am J Epidemiol 106:462–469, 1977. In a prospective study carried out on a cohort of 17,942 women belonging to the Kaiser Foundation Health Plan and...

To ascertain whether there are ear-hemisphere asymmetries of selective attention, signal stimuli (tonal sequences) were presented monaurally with and without complex maskers (music and speech). The right ear-left hemisphere was more disrupted by language maskers; the left ear-right hemisphere was more disrupted by music maskers. These results sugge...

The frequency with which clue cells could be detected in Gram-stained vaginal smears and/or cervical Papanicolaou (Pap) smears was compared with the frequency of Corynebacterium vaginale (Haemophilus vaginalis) isolation in a group of 236 female patients, of whom 221 had vaginitis. Vaginal clue cells were found most often in women from whom C. vagi...

Let $\{X_n\}$ be a sequence of i.i.d. random variables, each with probability density function $p(x \mid \theta, \xi)$ subject to certain regularity conditions. Here, $\theta$ is an $s$-dimensional vector of nuisance parameters, and $\xi \in (-r, r)$ is the parameter under test. The first $N$ members of the sequence $\{X_n\}$ are to be used for tes...

Thesis (Ph. D. in Statistics)--University of California, Berkeley, March 1972. Includes bibliographical references.