Efficient Algorithms for Determining 3-D Bi-Plane Imaging Geometry

Biplane projection imaging is one of the primary methods for imaging and visualizing the cardiovascular system in medicine. A key problem in such a technique is to determine the imaging geometry (i.e., the relative rotation and translation) of two projections so that the 3-D structure can be accurately reconstructed. Based on interesting observations and efficient geometric techniques, we present in this paper new algorithmic solutions for this problem. Comparing with existing optimization-based approaches, our techniques yield better accuracy and have bounded execution time, thus is more suitable for on-line applications. Our techniques can easily detect outliers to further improve the accuracy.This research was supported in part by NIH under USPHS grant numbers HL52567.     

Research misconduct and crime lessons from criminal science on preventing misconduct and promoting integrity

For 200 years, criminologists theorized that delinquent and criminal acts arise from deviant psychological states (such as irrationality or immorality) and/or social conditions that produce these psychological states. This theoretical perspective, which is being duplicated in most efforts to understand and control research misconduct, has not been productive. More recently, criminological perspectives have emerged, emphasizing situational factors that enhance or restrict the opportunity for illegal or imprudent behavior. These so-called "opportunity" theories have been shown to have practical value in reducing crime rates. We explore the promise of these newer theories for the responsible conduct of research (RCR).     

How Unique Are the Price–Anderson Limitations on Nuclear Accident Liability?

In this paper we extend the work reported in prior studies. The conclusion drawn from the aggregate of those studies was that the limitation on liability imposed by the Price–Anderson Act for a catastrophic accident at a nuclear power plant ($560 million) is comparable to de facto limitations on recovery following catastrophic events in many other industries. The analysis in those reports was at a high level of abstraction, comparing almost exclusively the potential loss from high consequence accidents with the current assets of major firms in relevant industries. We found that potential loss exceeded assets.     

The family size utility function

This article discusses the family size utility function (FSUF), which portrays the relative strengths of preferences among family sizes, as held by an individual, couple, or group. Derivable from the FSUF are indications of motivation to seek or avoid additional children, indications which may prove useful for understanding fertility decisions and for predicting completed fertility. A method is described for assessing the FSUF with data obtainable by interview surveys, and case studies of actual FSUF’s are presented. The article concludes with theoretical and empirical questions for further investigation of the FSUF.     

Asymptotic Expansions for i.i.d. Sums Via Lower-order Convolutions

In this article, we introduce new asymptotic expansions for probability functions of sums of independent and identically distributed random variables. Results are obtained by efficiently employing information provided by lower-order convolutions. In comparison with Edgeworth-type theorems, advantages include improved asymptotic results in the case of symmetric random variables and ease of computation of main error terms and asymptotic crossing points. The first-order estimate can perform quite well against the corresponding renormalized saddlepoint approximation and, pointwise, requires evaluation of only a single convolution integral. While the new expansions are fairly straightforward, the implications are fortuitous and may spur further related work.     

Some further aspects of the löwner-ordering antitonicity of the moore-penrose inverse

A survey is given of known proofs of the antitonicity of the inverse matrix function for positive definite matrices w.r.t. the Lowner partial ordering, and of the corresponding result for the Moore-Penrose inverse of nonnegative definite matrices [the theorem of Milliken and Akdeniz (1977)]. A short new proof of the latter result is obtained by employing an extremal representation of a nonnegative definite quadratic form. Another proof of this result involving Schur complements is also given, and is seen to be extendable to the case of symmetric (not necessarily nonnegative definite) matrices. A geometrical interpretation of Milliken and Akdeniz's theorem is presented. As an application, the relationship between the concepts of greater (maximum) concentration and smaller (minimum) dispersion is considered for a pair (class) of vector-valued statistics with possibly degenerate distributions.