Search

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.cogpsych.2006.06.003 Byline: John R. Anderson (a), Yulin Qin (a), Kwan-Jin Jung (b), Cameron S. Carter (c) Keywords: Cognitive architecture; fMRI Abstract: This research uses fMRI to understand the role of eight cortical regions in a relatively complex information-processing task. Modality of input (visual versus auditory) and modality of output (manual versus vocal) are manipulated. Two perceptual regions (auditory cortex and fusiform gyrus) only reflected perceptual encoding. Two motor regions were involved in information rehearsal as well as programming of overt actions. Two cortical regions (parietal and prefrontal) performed processing (retrieval and representational change) independent of input and output modality. The final two regions (anterior cingulate and caudate) were involved in control of cognition independent of modality of input or output and content of the material. An information-processing model, based on the ACT-R theory, is described that predicts the BOLD response in these regions. Different modules in the theory vary in the degree to which they are modality-specific and the degree to which they are involved in central versus peripheral cognitive processes. Author Affiliation: (a) Psychology Department, Carnegie Mellon University, Pittsburgh, PA 15213, USA (b) Brain Imaging Research Center, University of Pittsburgh and Carnegie Mellon University, Pittsburgh, PA 15203, USA (c) Departments of Psychiatry and Psychology, University of California at Davis, Sacramento, CA 95817, USA Article History: Accepted 25 June 2006

The development of lateral control skills is crucial to driving safety. The current study examined a computational method using a cognitive architecture to model the learning process of vehicle lateral control. In a fixed-base driving simulator, an experiment compared the lateral control performance of non-drivers, novices, and experienced drivers. A cognitive model using Adaptive Control of Thought-Rational (ACT-R) was built to model the learning process of lateral control skills. The modeling results were compared with the human results. The drivers with more experience had better lateral control performance. The model produced similar results as the human results and modeled the progress of learning. The model provided a computational explanation for the mechanisms of lateral control skill learning. Implication and future studies were discussed. [ABSTRACT FROM AUTHOR]

The CoCrFeNiMo 0.4 high-entropy alloys (HEAs) were synthesized by a high-pressure solid-state reaction at 3–5 GPa and held for 3–10 min at 1200 °C. The microstructure and mechanical properties of the sample were influenced by the pressure and holding time, which was confirmed when the Co, Cr, Fe, Ni, and Mo atoms diffused to form HEAs. The increased pressure hindered the diffusion between atoms and thus inhibited the formation of HEAs. Under the influence of the enthalpy of mixing between elements, Fe had the strongest repulsive force on the system and the weakest diffusion effect, but increasing the holding time promoted the diffusion of Fe atoms. Compared with the microhardness reported in other studies, the maximum hardness in our work was 449.1 HV, which represents a maximum increase of approximately 80%. The synergistic effects of the solid-solution strengthening of the system and the serious lattice distortion effect caused by large Mo atoms and high pressure were the dominant mechanisms responsible for the enhanced microhardness of the sintered HEAs under extreme conditions. • Under extreme conditions, as the pressure increases, atoms are squeezed and long-range diffusion between atoms is impeded, thus inhibiting the formation of HEAs. However, CoCrFeNiMo 0.4 HEAs can be synthesized below the atmospheric melting point of each element. • Under the influence of the enthalpy of mixing between elements, Fe had the strongest repulsive force on the system and the weakest diffusion effect. The diffusion of Fe can be promoted by increasing the holding time. • Compared with hardness values of 250 HV and 375 HV reported in other studies, the maximum hardness of our sample was 449.1 HV, increases of approximately 80% and 20%, respectively. [ABSTRACT FROM AUTHOR]

• The LJF consists of mainly paraffinic and cycloparaffinic hydrocarbons. • The LJF has a much higher average carbon number than conventional fuel. • The LJF has favorable energy content and energy density. • The LJF has possible low emission and high performance drop-in specifications. Sustainable aviation fuels remain the only near, mid, and likely long term solution for lowering the carbon emissions of commercial and military aviation. Determination of sustainable aviation fuel's chemical compositions and prediction of their properties is a critical first step for further research and development leading to the final certification process. Our analytical results showed that the lignin-based jet fuel (US patent 9,518,076 B2) consists of mainly paraffinic hydrocarbon species. They can be further classified into several classes, including n-paraffins, iso-paraffins, mono-, di-, and tri-cycloparaffins of which the majority contains carbon numbers in the range of 7–20. The very high concentration of polycycloparaffins along with the relatively low content of monocycloparaffins contribute to the high boiling point of the sample. Reducing the boiling point will require cracking and further hydrotreating of the lignin-based jet fuel range hydrocarbons to increase monocycloparaffins ratio close to the coal-based jet fuel compositions (e.g., JP-900). Also, this lignin-based jet fuel contains very low aromatics concentration which illuminates favorable energy content, energy density, possible low emissions, and very high-performance characteristics might meet drop-in specifications. [ABSTRACT FROM AUTHOR]

Highlights: [•] We built a model to illustrate the decelerate operation caused by traffic signs. [•] We employ a simulator experiment to test the rationality of the model. [•] The different placements of traffic sign impact the drivers’ deceleration when it placed far from the curve. [•] The curve radius and trial number are highly related to the process of information perception. [Copyright &y& Elsevier]

The methodologies of cognitive architectures and functional magnetic resonance imaging can mutually inform each other. For example, four modules of the ACT-R (adaptive control of thought – rational) cognitive architecture have been associated with four brain regions that are active in complex tasks. Activity in a lateral inferior prefrontal region reflects retrieval of information in a declarative module; activity in a posterior parietal region reflects changes to problem representations in an imaginal module; activity in the anterior cingulate cortex reflects the updates of control information in a goal module; and activity in the caudate nucleus reflects execution of productions in a procedural module. Differential patterns of activation in such central regions can reveal the time course of different components of complex cognition. [Copyright &y& Elsevier]