Reconstruction of surface discontinuities from unorganized 3D points is a difficult problem. Both the polygonization and surface fitting approaches to surface reconstruction face the same chicken-and-egg problem: to correctly reconstruct surface discontinuities, the points that lie on the same side of the discontinuities should be used to reconstruct the surfaces to form the discontinuities. Ho...

Shock ripples and shock–discontinuity interactions (SDIs) have long been proposed to explain the frequent occurrence of high-speed jets (HSJs) in magnetosheath; however, there is no direct observational evidence for either them occurring near a shock. Herein, we report large-scale, long-duration undulated quasi-perpendicular shock surface that capable generating HSJs. Based on curvatures estima...

We discuss Minkowski space interpretations of euclidean solutions which provide semiclassical approximations to quantum processes. In particular, we consider wormhole and euclidean bounce solutions. We argue that the semiclassical description involves an instantaneous discontinuity in the Minkowski signature classical evolution and that the euclidean solutions provide final and initial value da...

Experiments in Surface Perception using a Fingertip Haptic Display by Steven Craig Venema Chairperson of Supervisory Committee: Professor Blake Hannaford Department of Electrical Engineering A haptic display provides the mechanical analog of a physical environment for our sense of touch in a virtual reality (VR) simulation system. In this dissertation, we explore the design and implementation o...

This paper introduces ‘treatable’ theories, a large class of first-order theories each having a unique countable recursively saturated model.Important examples of such theories are DIS and DLO. It turns out that resplendency or parameter-free resplendency for such theories is implied by a Σ1(Π1 ThN)-statement. Other results concerning resplendency and Σ1definability are obtained.

This paper describes the interim results of a study to characterize discontinuous rock masses using 3D laser scanning data. One of the main advantages of this method is that now an unbiased, rapid and accurate discontinuity analysis can be done. With 3D laser scanning it is now also possible to measure rock faces whose access is restricted or rock slopes along highways or railway lines where wo...

The evolution of discontinuity and formation of triple-shock pattern in solutions to a two-dimensional hyperbolic system of conservation laws are studied. When the initial discontinuity is a convex curve, it is discovered that the structure of the global solution changes dramatically around a critical time: After the critical time, a triple-shock pattern forms, while, before the critical time, ...

It is generally accepted that the identification and characterisation of discontinuities in discontinuous rock masses is one of the most important aspects in rock mass modelling. Traditional manual field survey methods for gathering discontinuity properties are biased, hazardous, difficult and time-consuming. This paper describes a computer approach, based on terrestrial laser scan data, which ...

We use covariance and dimensional analysis to find expressions for the discontinuity of the potential and normal electric field across a flat surface with multipolar charge surface density in vacuum. In particular we show that δEz = ∞