The effects of estimation of censoring, truncation, transformation and partial data vectors

The purpose of this research was to attack statistical problems concerning the estimation of distributions for purposes of predicting and measuring assembly performance as it appears in biological and physical situations. Various statistical procedures were proposed to attack problems of this sort, that is, to produce the statistical distributions of the outcomes of biological and physical situations which, employ characteristics measured on constituent parts. The techniques are described

Tensor distributions on signature-changing space-times

Irregularities in the metric tensor of a signature-changing space-time suggest that field equations on such space-times might be regarded as distributional. We review the formalism of tensor distributions on differentiable manifolds, and examine to what extent rigorous meaning can be given to field equations in the presence of signature-change, in particular those involving covariant derivatives. We find that, for both continuous and discontinuous signature-change, covariant differentiation can be defined on a class of tensor distributions wide enough to be physically interesting.Comment: 9 pages, LaTeX 2.0

Oral History Interview: W. Hartley Fulks

This interview is one of a series concerning workers in various West Virginia industries and businesses. Mr. Fulks is a retired butcher and grocery man from Huntington, West Virginia. At the time of the interview he was living on Greasey Ridge in Ohio. Mr. Fulks talks about farming and his business.https://mds.marshall.edu/oral_history/1093/thumbnail.jp

Contact-Aided Invariant Extended Kalman Filtering for Legged Robot State Estimation

This paper derives a contact-aided inertial navigation observer for a 3D bipedal robot using the theory of invariant observer design. Aided inertial navigation is fundamentally a nonlinear observer design problem; thus, current solutions are based on approximations of the system dynamics, such as an Extended Kalman Filter (EKF), which uses a system's Jacobian linearization along the current best estimate of its trajectory. On the basis of the theory of invariant observer design by Barrau and Bonnabel, and in particular, the Invariant EKF (InEKF), we show that the error dynamics of the point contact-inertial system follows a log-linear autonomous differential equation; hence, the observable state variables can be rendered convergent with a domain of attraction that is independent of the system's trajectory. Due to the log-linear form of the error dynamics, it is not necessary to perform a nonlinear observability analysis to show that when using an Inertial Measurement Unit (IMU) and contact sensors, the absolute position of the robot and a rotation about the gravity vector (yaw) are unobservable. We further augment the state of the developed InEKF with IMU biases, as the online estimation of these parameters has a crucial impact on system performance. We evaluate the convergence of the proposed system with the commonly used quaternion-based EKF observer using a Monte-Carlo simulation. In addition, our experimental evaluation using a Cassie-series bipedal robot shows that the contact-aided InEKF provides better performance in comparison with the quaternion-based EKF as a result of exploiting symmetries present in the system dynamics.Comment: Published in the proceedings of Robotics: Science and Systems 201

The Problem of Membership in International Organization

Membership problems plague international organizations of all types. All organizations are in some way exclusive, and there is a hierarchy of acceptable joiner-nations with the European nations leading the list. Each organization appears statistically to have a norm of membership toward which its number tends. If it falls short of the norm, it is under compulsion to expand. If it exceeds the norm, expulsions or boycotts are likely to ensue. The ideal condition of an organization, therefore, is normal membership, not necessarily total inclusion of all nations legally admissable. More is to be lost by too large an organization than by one too small. There is a superfluity of discrete national memberships in separate organizations, which necessitates amalgamation of organizations

Ground-level insolation in the UV-B spectral region : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Physics at Massey University

This thesis describes the design and construction of two instruments for use in isolating the ultraviolet parts of the Solar spectral irradiance at Earth's surface. The first was a total UVA Pyranometer, which was undertaken to make preliminary investigations in the techniques of monitoring ultraviolet irradiances, as well as to provide useful data. The main part of this thesis was the construction of a portable, easily operated, interference filter spectrophotometer to isolate the ultraviolet-B spectrum into five discrete 10 nm passbands. However, as further reading will describe, realisation of only the two longer wavelength passbands was made due to deviations from the ideal quasi-rectangular passbands of the interference filter spectral transmittance curves. Discussion of how these problems can be overcome is presented in the conclusion. An outline on how the incident spectral solar irradiance could be found, from the five passbands, is presented along with some preliminary data from the two operational channels. An overall accuracy of 15% was obtained for data obtained, with better accuracies, to 7%, attainable by stabilisation of the instrument power supplies and, therefore, output voltage

Stochastic compartmental analysis - Some applications and examples of estimation in a pulse labelled system

Stochastic compartmental analysis with examples of estimation in pulse labelled syste