Search

In high demand contexts, uni- or multi-modal signals are used to convey redundant information and improve performance. This is especially the case with improving the detection of discrete peripheral signals. However, how one processes peripheral signals may change depending on the greater environmental context. The underlying cognitive processing of signals is important to determine how they may influence the degree to which each signal enhances, as opposed to slows down, detection. Until now, it was unclear if i) the introduction of, or increased difficulty of, a second task changes how people combine peripheral signals (that is, in a parallel, serial, or coactive fashion) and ii) if processing efficiency depends on the salience of the peripheral signals or the presence/difficulty of a centrally located and continuous tracking task. This manuscript describes an application of Systems Factorial Technology to investigate the cognitive processing mechanisms of redundant signals in the context of a multiple object tracking (MOT) task. The MOT task load (track 0, 1, or 4 dots) and the salience of peripheral signals (bright, dim) were manipulated. The data indicate peoples' processing of peripheral signals changed depending on the MOT task load. Under a high MOT task load, most people processed redundant signals in a parallel fashion. Alternatively, nearly half of people processed the signals in a serial fashion when asked to simultaneously track 0 or 1 dot. Implications for the use and design of redundant signals in multi-task contexts that vary in task demands are discussed.

The spatial high-resolution synthetic aperture radar (SAR) for ocean exploration puts forward higher requirement for output power and amplitude-phase consistency of the pulsed TWT amplifier. The kW class pulsed TWT amplifier based on broadband power combining is the key technology for space SAR applications. In this paper, the factors affecting the amplitude and phase consistency of MPM are studied, and a phase consistency compensation circuit was designed to improve the phase consistency of multiple sets of products. A microwave power model (MPM) with dual TWTs output integrated architecture was proposed which consists of two short travelling wave tubes (TWT), two solid-state power amplifiers (SSPA), and an electronic power conditioner (EPC). More than 45% efficiency is achieved in 15% duty cycle within 600 MHz bandwidth, and the phase consistency was less than ± 5 degrees.With the improvement of synthesis efficiency, higher synthesis power and higher sensitivity of ocean wide scanning and detection can be obtained

The preparation of nanocrystalline aluminum (NC Al) was conducted in two steps. After the NC Al powder was synthesized by an Inert gas condensation (IGC) method in a helium atmosphere of 500 Pa, the NC Al powder was in-situ compacted into a pellet with a 10 mm diameter and 250 μm-300 μm thickness in a high vacuum (10-6 Pa-10-7 Pa) at room temperature. The NC Al samples were not exposed to air during the entire process. After the pressure reached 6 GPa, the relative density could reach 99.83%. The results showed that the grain size decreased with the increased of in-situ forming pressure. The NC Al samples present obvious ductile fracture, and the tensile properties were greatly changed with the increase of forming pressure.