Lexical stress representation in spoken word recognition

According to a popular model of speech production, stress is underspecified in the lexicon, that is, it is specified only for words with stress patterns other than the default, termed the “default metrics” assumption. Alternatively, stress may be fully specified in the lexicon as part of every lexical representation. In the current study the two accounts are tested in the perceptual domain using behavioral and eye-tracking data in Greek. In a first experiment, cross-modal fragment priming was used in a lexical decision task. According to default metrics, priming should occur for targets with antepenultimate- or final-syllable stress but not for targets with the default penultimate-syllable stress. The same word pairs were used in two subsequent visual world experiments. Default metrics predicts an asymmetric pattern of results, namely that incoming spoken words with the default stress pattern should inhibit the activation of lexical representations with nondefault stress, whereas the converse should not be observed; that is, spoken words with nondefault stress should not inhibit representations of words with the default stress. None of the results provided support for the idea of default metrics, leading to alternative conceptualizations regarding the representation of stress.

Predicting Distortion in Butt Welded Plates Using an Equivalent Plane Stress Representation Based on Inherent Shrinkage Volume

Due to the adverse effect that distortion has on assembly fit-up and fabrication costs in welded structures, the ability to predict dimensional changes represents an important engineering concern. While distortion can be analyzed using a full three-dimensional (3D) finite element (FE) model, this often proves to be computationally expensive for medium and large structures. In comparison, a two-dimensional (2D) FE model can significantly reduce the time and effort needed to analyze distortion though such analyses often have reduced accuracy. To address these issues, a 3D plane stress model using shell meshes based on the shrinkage volume approach is proposed. By inversing the plastic shrinkage zone geometry, an eccentric loading condition and equivalent plane stress representation can be developed and used to predict distortion in butt welded plates using an isothermal model. The model was validated using deflection data from welded plates and found to provide good accuracy over the range of thicknesses considered. Results obtained from welding of a large containment tank are also presented and further confirm the utility of the method.

Wave–Current Interaction: A Comparison of Radiation-Stress and Vortex-Force Representations

The vortex-force representation of the wave-averaged effects on currents is compared to the radiation-stress representation in a scaling regime appropriate to coastal and shelf waters. Three-dimensional and vertically integrated expressions for the conservative current equations are obtained in both representations. The vortex-force representation decomposes the main wave-averaged effects into two physically understandable concepts—a vortex force and a Bernoulli head. The vortex force is shown to be the dominant wave-averaged effect on currents. This effect can occur at higher order than the apparent leading order for the radiation-stress representation. Excluding nonconservative effects such as wave breaking, the lowest-order radiation or interaction stress can be completely characterized in terms of wave setup, forcing of long (infragravity) waves, and an Eulerian current whose divergence cancels that of the primary wave Stokes drift. The leading-order, wave-averaged dynamical effects incorporate the vortex force together with material advection by Stokes drift, modified pressure-continuity and kinematic surface boundary conditions, and parameterized representations of wave generation by the wind and breaking near the shoreline.