1,845 research outputs found

    The Effectiveness of Insurance Fraud Statutues: Evidence from Automobile Insurance

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    Insurance fraud, which adds an estimated $85 billion per year to the total insurance bill in the U.S., is an extremely serious problem for consumers, regulators, and insurance companies. This paper analyzes the effects of state legislation and market conditions on automobile insurance fraud from 1988 to 1999, a period representing a substantial increase in the enactment of antifraud legislation. Our empirical results show that the laws have mixed effects; two laws have no statistically significant effect on fraud. The strongest evidence of fraud mitigation effects are associated with mandatory Special Investigation Units, classification of insurance fraud as a felony, and mandatory reporting of professionals to licensing authorities. However, laws requiring insurers to report potentially fraudulent claims to law enforcement authorities increase fraud, which may reflect some substitution from more efficacious private efforts to less productive state activity. Many underlying characteristics of the market also affect fraud.Insurance Fraud, Automobile Insurance, Moral Hazard

    MODIS information, data and control system (MIDACS) operations concepts

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    The MODIS Information, Data, and Control System (MIDACS) Operations Concepts Document provides a basis for the mutual understanding between the users and the designers of the MIDACS, including the requirements, operating environment, external interfaces, and development plan. In defining the concepts and scope of the system, how the MIDACS will operate as an element of the Earth Observing System (EOS) within the EosDIS environment is described. This version follows an earlier release of a preliminary draft version. The individual operations concepts for planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, data archive and distribution, and user access do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams are not yet formed; however, it is possible to develop the operations concepts based on the present concept of EosDIS, the level 1 and level 2 Functional Requirements Documents, and through interviews and meetings with key members of the scientific community. The operations concepts were exercised through the application of representative scenarios

    MODIS Information, Data, and Control System (MIDACS) system specifications and conceptual design

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    The MODIS Information, Data, and Control System (MIDACS) Specifications and Conceptual Design Document discusses system level requirements, the overall operating environment in which requirements must be met, and a breakdown of MIDACS into component subsystems, which include the Instrument Support Terminal, the Instrument Control Center, the Team Member Computing Facility, the Central Data Handling Facility, and the Data Archive and Distribution System. The specifications include sizing estimates for the processing and storage capacities of each data system element, as well as traffic analyses of data flows between the elements internally, and also externally across the data system interfaces. The specifications for the data system, as well as for the individual planning and scheduling, control and monitoring, data acquisition and processing, calibration and validation, and data archive and distribution components, do not yet fully specify the data system in the complete manner needed to achieve the scientific objectives of the MODIS instruments and science teams. The teams have not yet been formed; however, it was possible to develop the specifications and conceptual design based on the present concept of EosDIS, the Level-1 and Level-2 Functional Requirements Documents, the Operations Concept, and through interviews and meetings with key members of the scientific community

    MODIS information, data and control system (MIDACS) level 2 functional requirements

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    The MODIS Information, Data and Control System (MIDACS) Level 2 Functional Requirements Document establishes the functional requirements for MIDACS and provides a basis for the mutual understanding between the users and the designers of the EosDIS, including the requirements, operating environment, external interfaces, and development plan. In defining the requirements and scope of the system, this document describes how MIDACS will operate as an element of the EOS within the EosDIS environment. This version of the Level 2 Requirements Document follows an earlier release of a preliminary draft version. The sections on functional and performance requirements do not yet fully represent the requirements of the data system needed to achieve the scientific objectives of the MODIS instruments and science teams. Indeed, the team members have not yet been selected and the team has not yet been formed; however, it has been possible to identify many relevant requirements based on the present concept of EosDIS and through interviews and meetings with key members of the scientific community. These requirements have been grouped by functional component of the data system, and by function within each component. These requirements have been merged with the complete set of Level 1 and Level 2 context diagrams, data flow diagrams, and data dictionary

    MODIS-HIRIS ground data systems commonality report

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    The High Resolution Imaging Spectrometer (HIRIS) and Moderate Resolution Imaging Spectrometer (MODIS) Data Systems Working Group was formed in September 1988 with representatives of the MODIS Data System Study Group and the HIRIS Project Data System Design Group to collaborate in the development of requirements on the EosDIS necessary to meet the science objectives of the two facility instruments. A major objective was to identify and promote commonality between the HIRIS and MODIS data systems, especially from the science users' point of view. A goal was to provide a base set of joint requirements and specifications which could easily be expanded to a Phase-B representation of the needs of the science users of all EOS instruments. This document describes the points of commonality and difference between the Level-II Requirements, Operations Concepts, and Systems Specifications for the ground data systems for the MODIS and HIRIS instruments at their present state of development

    Records in a changing world

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    In the context of this paper, a record is an entry in a sequence of random variables (RV's) that is larger or smaller than all previous entries. After a brief review of the classic theory of records, which is largely restricted to sequences of independent and identically distributed (i.i.d.) RV's, new results for sequences of independent RV's with distributions that broaden or sharpen with time are presented. In particular, we show that when the width of the distribution grows as a power law in time nn, the mean number of records is asymptotically of order lnn\ln n for distributions with a power law tail (the \textit{Fr\'echet class} of extremal value statistics), of order (lnn)2(\ln n)^2 for distributions of exponential type (\textit{Gumbel class}), and of order n1/(ν+1)n^{1/(\nu+1)} for distributions of bounded support (\textit{Weibull class}), where the exponent ν\nu describes the behaviour of the distribution at the upper (or lower) boundary. Simulations are presented which indicate that, in contrast to the i.i.d. case, the sequence of record breaking events is correlated in such a way that the variance of the number of records is asymptotically smaller than the mean.Comment: 12 pages, 2 figure

    Colloquium: Theory of Drag Reduction by Polymers in Wall Bounded Turbulence

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    The flow of fluids in channels, pipes or ducts, as in any other wall-bounded flow (like water along the hulls of ships or air on airplanes) is hindered by a drag, which increases many-folds when the fluid flow turns from laminar to turbulent. A major technological problem is how to reduce this drag in order to minimize the expense of transporting fluids like oil in pipelines, or to move ships in the ocean. It was discovered in the mid-twentieth century that minute concentrations of polymers can reduce the drag in turbulent flows by up to 80%. While experimental knowledge had accumulated over the years, the fundamental theory of drag reduction by polymers remained elusive for a long time, with arguments raging whether this is a "skin" or a "bulk" effect. In this colloquium review we first summarize the phenomenology of drag reduction by polymers, stressing both its universal and non-universal aspects, and then proceed to review a recent theory that provides a quantitative explanation of all the known phenomenology. We treat both flexible and rod-like polymers, explaining the existence of universal properties like the Maximum Drag Reduction (MDR) asymptote, as well as non-universal cross-over phenomena that depend on the Reynolds number, on the nature of the polymer and on its concentration. Finally we also discuss other agents for drag reduction with a stress on the important example of bubbles.Comment: Invited Colloquium Paper for Reviews of Modern Physics, 24 pages, 18 Figs., submitte

    Nutrition impacts the prevalence of peripheral arterial disease in the United States

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    ObjectiveTraditional recommendations for peripheral arterial disease (PAD) risk factor reduction include smoking cessation, low-fat/low-salt diet, exercise, and optimal medical management of chronic disease. Little attention has been paid to the role of dietary supplementation of specific nutrients in the prevention of PAD.MethodsThis cross-sectional study used the National Health and Nutrition Examination Survey (NHANES) to determine specific nutrients that are associated with prevalent PAD in the United States (US) population. NHANES data include nationwide sampling of the US population, using physical examination, questionnaire, and laboratory testing. PAD status was defined by an ankle-brachial index (ABI) of <0.9. Nutritional information was collected by 24-hour dietary recall using the US Department of Agriculture dietary collection instrument. Data were linked to a database of foods and their nutrient composition. Univariate and multivariate logistic regression analyses were performed to evaluate associations between specific nutrient intake and the presence of PAD. Multivariate models adjusted for the effects of age, gender, hypertension, coronary vascular disease, diabetes, and smoking.ResultsNHANES data for 1999 to 2004 included 7203 lower extremity examinations, of which 422 individuals had prevalent PAD (5.9%). Examinees with PAD had significantly higher rates of hypertension, coronary artery disease, diabetes, and smoking than those without PAD. Univariate analysis revealed that consumption of all nutrients considered were associated with lower odds of PAD, including antioxidants (vitamins A, C, and E), folate, other B vitamins (B6, B12), fiber, and polyunsaturated and saturated fatty acids. After adjustment for traditional risk factors, nutrients associated with reduced prevalence of PAD were vitamin A (odds ratio [OR], 0.79; P = .036), vitamin C (OR, 0.84; P < .001), vitamin E (OR, 0.78; P = .011), vitamin B6 (OR, 0.71; P = .023), fiber (OR, 0.65; P < .001), folate (OR, 0.67; P = .006), and ω-3 (α-linolenic) fatty acid (OR, 0.79; P = .028).ConclusionsImproved nutrition is associated with a reduced prevalence of PAD in the US population. Higher consumption of specific nutrients, including antioxidants (vitamin A, C, and E), vitamin B6, fiber, folate, and ω-3 fatty acids have a significant protective effect, irrespective of traditional cardiovascular risk factors. These findings suggest specific dietary supplementation may afford additional protection, above traditional risk factor modification, for the prevention of PAD
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