We investigated whether the expertise of a perceiver and the physical complexity of a stimulus influence consolidation of visual short-term memory (VSTM) in a S1-S2 (Stimulus 1-Stimulus 2) change detection task. Consolidation is assumed to make transient perceptual representations in VSTM more durable, and it is investigated by postexposure of a mask shortly after offset of the perceived stimulus (S1; 17 to 483 ms). We presented colours, Chinese characters, pseudocharacters, and novel symbols to novices (Germans) or experts of Chinese language (Chinese readers). Physical complexity was manipulated by the number of strokes. Unfamiliar material was remembered worse than familiar material (Experiments 1, 2, and 3). For novices the absolute VSTM performance was better for physically simple than for complex material, whereas for experts the complexity did not matter-Chinese readers memorized Chinese characters (Experiment 3). Articulatory suppression did not change these effects (Experiment 2). We always observed a strong effect of SOA, but this effect was influenced neither by physical complexity nor by expertise; only the length of the interstimulus interval between S1 and the mask was relevant. This was observed even with short stimulus onset asynchrony (SOA) of 100 ms (Experiment 2) and in comparing colours and characters (Experiment 5). However, masks impaired memory if they were presented at the locations of the to-be-memorized items, but not beside them-that is, interference was location-based (Experiment 6). We explain the effect of SOA by the assumption that it takes time to stop encoding of information presented at item locations with the offset of S1. The increasing resistance against interference by irrelevant material appears as consolidation of S1.

In this paper, the problem of boundary finite-time stabilization is considered for reaction-diffusion systems (RDSs). First, a full-domain controller is designed, and sufficient conditions are given to ensure finite-time stability of RDSs under the designed controller. Then, for practical applications, a boundary controller is designed to obtain finite-time stability. By virtue of the finite-time stability lemma, criteria are presented to guarantee the finite-time stability of RDSs for the Neumann boundary conditions and the mixed boundary conditions. As an extension to uncertain RDSs, robust finite-time stabilization is studied, and criterion is obtained under the boundary control. Numerical simulations verify the effectiveness of the proposed design techniques. KEYWORDS boundary control, finite-time stability, full-domain control, reaction-diffusion systems, uncertain reaction-diffusion systems Recently, the research of finite-time stability for partial differential systems has also attracted some interest. 19,20 The reaction-diffusion system (RDS) has been widely used to characterize the system dynamics found in applications in the chemical processes, fluid flows, and biological pattern formation (see previous works 21-28 for a survey). The stabilization of RDSs has attracted significant interest. 21,[24][25][26] For RDSs, there exists a specific control strategy and a boundary control. [29][30][31][32][33] While the boundary stabilization for RDSs has been well investigated, 34,35 only a few reported the finite-time boundary stabilization for RDSs. This paper focuses on the finite-time boundary stabilization for RDSs. How the boundary controller can be designed remains a main challenge since there exist a few results available for use. To provide the necessary theoretical framework in the study, we first derive a full-domain controller for reaching finite-time stability of RDSs. Making use of the finite-time stability lemma and Wirtinger's inequality, we present sufficient conditions to guarantee the finite-time stability under Int J Robust Nonlinear Control. 2018;28:1641-1652.wileyonlinelibrary.com/journal/rnc

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The current study investigated whether people can simultaneously acquire knowledge about concrete chunks and abstract structures in implicit sequence learning; and whether the degree of abstraction determines the conscious status of the acquired knowledge. We adopted three types of stimuli in a serial reaction time task in three experiments. The RT results indicated that people could simultaneously acquire knowledge about concrete chunks and abstract structures of the temporal sequence. Generation performance revealed that ability to control was mainly based on abstract structures rather than concrete chunks. Moreover, ability to control was not generally accompanied with awareness of knowing or knowledge, as measured by confidence ratings and attribution tests, confirming that people could control the use of unconscious knowledge of abstract structures. The results present a challenge to computational models and theories of implicit learning.

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