Klaus-Peter Beier

Highlight-line algorithm for realtime surface-quality assessment

Abstract A new method of surface-quality assessment is presented. The model of highlight lines is introduced, and its properties and applications in surface-quality evaluation are demonstrated. The differential equation of the highlight-line model is derived, and the difficulty involved in seeking its analytical solutions is discussed. Alternatively, the creation of highlight lines is formulated as a surface-plane intersection problem, and solved using surface-contouring techniques. A fast highlight-line algorithm is developed utilizing an efficient traced contouring technique. The algorithm is robust, fully automatic, and, therefore, well suited for realtime quality-assessment tasks.

Using immersive simulation for training first responders for mass casualty incidents.

OBJECTIVES A descriptive study was performed to better understand the possible utility of immersive virtual reality simulation for training first responders in a mass casualty event. METHODS Utilizing a virtual reality cave automatic virtual environment (CAVE) and high-fidelity human patient simulator (HPS), a group of experts modeled a football stadium that experienced a terrorist explosion during a football game. Avatars (virtual patients) were developed by expert consensus that demonstrated a spectrum of injuries ranging from death to minor lacerations. A group of paramedics was assessed by observation for decisions made and action taken. A critical action checklist was created and used for direct observation and viewing videotaped recordings. RESULTS Of the 12 participants, only 35.7% identified the type of incident they encountered. None identified a secondary device that was easily visible. All participants were enthusiastic about the simulation and provided valuable comments and insights. CONCLUSIONS Learner feedback and expert performance review suggests that immersive training in a virtual environment has the potential to be a powerful tool to train first responders for high-acuity, low-frequency events, such as a terrorist attack.

Direct highlight line modification on nurbs surfaces

Abstract Reflection characteristics of surfaces, as visualized by highlight lines, are important design objectives in automotive styling. A method is presented that allows the direct modification of a highlight line on a NURBS surface. The algorithm presented will automatically adjust the control points of the NURBS surface resulting in a modified surface shape that produces the desired highlight line. A system of nonlinear equations is developed that expresses the relationship between NURBS control points and reference points on the highlight line. The inverse problem is solved through linearization by a first-order Taylor expansion. In addition, a shape control mechanism is introduced that distributes control point changes over the surface in a coherent and predictable way. With this mechanism, the user is able to interactively control the locality, or extent, of the surface modification while maintaining the desirable highlight line modification.

GLOBAL CONTACT DYNAMICS OF AN ICE-STRUCTURE INTERACTION MODEL

The interaction between a moving ice sheet and an elastic structure is studied using the analogue model of Matlock, et al. [1969]. The ice sheet is represented by a series of teeth with bilinear, discontinuous stiffness. A global analysis of the resulting dynamical system is performed. Using a combination of analytical and numerical techniques, periodic solutions are determined and basin boundaries of the Poincare map identified. While the total system dynamics are quite complex, two types of threshold solutions are found, each necessary but not sufficient in defining local separatrices.

LAGRANGIAN VELOCITY PROFILES IN THE WAKE OF A HIGH SPEED VESSEL

Abstract A video imaging technique is employed in a towing basin to obtain high resolution surface Lagrangian velocity observations in the centerline wake region of a high speed, twin screw surface vessel. Approximately 30,000 surface velocity realizations within the wake region extending from the stern to approximately six model ship lengths aft are used for comparison with both recent full-scale and numerical model results. Analysis of this data set reveals spatial decay rates in the mean and fluctuating velocity components which serve to identify relevant scales of motion and define candidate mechanisms for the persistence of these wakes in remotely sensed ocean surface data.