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Objective The aim of this study is to measure drivers’ attention to preview and their velocity and acceleration tracking error to evaluate two- and three-dimensional displays for following a winding roadway. Background Display perturbation techniques and Fourier analysis of steering movements can be used to infer drivers’ spatio-temporal distribution of attention to preview. Fourier analysis of tracking error time histories provides measures of position, velocity, and acceleration error. Method Participants tracked a winding roadway with 1 s of preview in low-fidelity driving simulations. Position and rate-aided vehicle dynamics were paired with top-down and windshield displays of the roadway. Results For both vehicle dynamics, tracking was smoother with the windshield display. This display emphasizes nearer preview positions and has a closer correspondence to the control-theoretic optimal attentional distributions for these tasks than the top-down display. This correspondence is interpreted as a form of stimulus–response compatibility. The position error and attentional signal-to-noise ratios did not differ between the two displays with position control, but with more complex rate-aided control much higher position error and much lower attentional signal-to-noise ratios occurred with the top-down display. Conclusion Display-driven influences on the distribution of attention may facilitate tracking with preview when they are similar to optimal attentional distributions derived from control theory. Application Display perturbation techniques can be used to assess spatially distributed attention to evaluate displays and secondary tasks in the context of driving. This methodology can supplement eye movement measurements to determine what information is guiding drivers’ actions. 

Using theoretical and computational modeling, we focus on dynamics of gels filled with uniformly dispersed ferromagnetic nanoparticles subjected to electromagnetic (EM) irradiation within the GHz frequency range. As a polymer matrix, we choose poly( N -isopropylacrylamide) gel, which has a low critical solution temperature and shrinks upon heating. When these composites are irradiated with a frequency close to the Ferro-Magnetic Resonance (FMR) frequency, the heating rate increases dramatically. The energy dissipation of EM signals within the magnetic nanoparticles results in the heating of the gel matrix. We show that the EM signal causes volume phase transitions, leading to large deformations of the sample for a range of system parameters. We propose a model that accounts for the dynamic coupling between the elastodynamics of the polymer gel and the FMR heating of magnetic nanoparticles. This coupling is nonlinear: when the system is heated, the gel shrinks during the volume phase transition, and the particle concentration increases, which in turn results in an increase of the heating rates as long as the concentration of nanoparticles does not exceed a critical value. We show that the system exhibits high selectivity to the frequency of the incident EM signal and can result in a large mechanical feedback in response to a small change in the applied signal. These results suggest the design of a new class of soft active gel-based materials remotely controlled by low power EM signals within the GHz frequency range.