A machine learning-driven framework for the property prediction and generative design of multiple principal element alloys

Multi-principal element alloys (MPEAs), inclusive of so-called high entropy alloys (HEAs), represent an innovative class of metallic materials that reveal unique properties and potentially broad applicability. However, the compositional complexity of MPEAs presents challenges in discerning physical mechanisms that control properties, and in harnessing such mechanisms to drive the design of new alloys. An ability to design metallic alloys that possess user-defined requisite properties has emerged as a critical area of interest within the field of materials science and engineering. This research illustrates how the integration of data science, machine learning (ML), and generative design strategies can evolve alloy design to a predictive, data-oriented approach. A comprehensive workflow utilising machine learning for feature analysis, property prediction, and generative design of novel MPEA generation is proposed. This workflow facilitates the examination and comparison of the predictive capabilities of ML models in determining the mechanical properties of MPEAs, providing insights into the influence of different design parameters. Additionally, by integrating a generative adversarial model, the prediction of novel MPEAs and anticipate their mechanical behaviours is revealed

Optimal Zero-Forcing precoding design : oversampled FB frame approach

This paper presents a frame analysis of Zero Forcing (ZF) precoding problem. It shows that from a frame point of view, the filter bank (FB) channel is a synthesis frame and its canonical dual analysis frame is the optimal ZF precoder under total power constraint. Based on this analysis, a new precoder design is presented. The new design removes the minimum phase assumption of polyphase FB channel in the existing methods and gives rise to optimal noncausal (stable) precoder. It provides a general framework for optimal zero-forcing precoding under total power constraint. The numerical results show that the new design outperforms existing causal stable design

The use of near infrared reflectance spectroscopy to identify the origin of oak shavings used in wine aging

Near infrared (NIR) reflectance spectroscopy combined with chemometrics was used to classify toasted and untoasted oak wood shavings sourced from two countries (France and USA). Oak wood shaving samples (n = 96) were scanned in the NIR region (680–2,500 nm) using a monochromator instrument operating in reflectance mode. Principal component analysis, partial least squares discriminant analysis (PLS-DA) and linear discriminant analysis (LDA) were used to classify the samples according to their country of origin and level of toasting. Full cross validation (leave-one-out) was used as the validation method when classification models were developed. Correct classification rates of 83, 87 and 100 % for samples sourced from USA, France and toasted treatment were obtained using PLS-DA. For LDA, correct classification rates of 80.4, 85 and 100 % were achieved for samples sourced from USA, France and toasted treatment, respectively. These results demonstrated the ability of NIR spectroscopy to discriminate between oak wood shavings sourced from two different countries and two levels of toasting. © 2014, Springer Science+Business Media New York

Updating memories: Changing the involvement of the prelimbic cortex in the expression of an infant fear memory

Recent work has found that infant rats (postnatal day (P) 18) do not require the prelimbic cortex (PL) to express learned fear, whereas older animals (adults and juveniles) do. In other words, there is a switch from a PL-independent fear expression system during infancy to a PL-dependent system later in life. The present study investigated whether the PL would be involved in fear expression in rats trained at P17 but tested at P23 (that is, as juveniles). The first two experiments showed that PL involvement in fear expression was determined by the age of the animal at the time of training rather than the animal's age at the time of test. More specifically, experiment 1 showed that expression of learned fear (measured by freezing, and elicited by a white noise previously paired with a shock) was PL-independent for memories that were acquired when the rat was P17 but then tested at P23. In experiment 2, rats trained at P23, when the PL is functionally mature, still required the PL to express fear when tested at P37. In the last experiment, using two different reactivation procedures, we showed that it is possible to update an infant memory and switch it from being PL-independent to being PL-dependent. Combined, these results have important implications for our understanding of the neural circuitry underlying fear expression across development and show that, at least in some cases, expression of fear responses learned early in life remain PL-independent even as the animal matures. © 2012

Differential involvement of the medial prefrontal cortex in the expression of learned fear across development

Studies have shown that in adult animals the medial prefrontal cortex (mPFC) is a critical brain region involved in fear regulation, with the prelimbic (PL) subregion being important for fear expression. However, few studies have examined whether the PL cortex is also involved in fear expression in infant animals. Five experiments, using immunohistochemical and temporary inactivation procedures, assessed the role of the PL in the expression of learned fear in postnatal day (PND) 18 (infant) and PND25 (juvenile) rats. We found that in juvenile rats expressing fear (measured through freezing) there was an increase in the number of phosphorylated mitogen-activated protein kinase (pMAPK)-labeled neurons in the PL; this increase was not observed in the infralimbic cortex. Furthermore, inactivation of the PL at test, using muscimol, decreased freezing in the juvenile rat. In contrast, expression of learned fear in infant rats did not require the PL, as there was neither an increase in the number of pMAPK-labeled cells in the PL nor was there any effect of PL inactivation on freezing levels. Taken together, these experiments suggest that a different neural circuitry underlies fear regulation early in life and that the lack of mPFC involvement may reflect a less flexible emotional regulation system in infant animals. © 2012 American Psychological Association

Theoretical analysis on ac susceptibility measurements of superconductor tapes

Perpendicular ac susceptibility X = X' - jX′ of a superconducting long tape defined by magnetic moment and determined inductively by magnetic flux is calculated using Brandt's technique from a power-law dependence of electric field on sheet current density. The requirements of X measurements to the experimental setup and procedure are discussed based on the calculation results

Peer performance and the asymmetric timeliness of earnings recognition

This paper investigates the impact of peer performance on the asymmetric timeliness of earnings recognition. We find a positive relationship between peers' weak performance and timely bad news disclosure. Our results are robust to a variety of tests, including instrument variable approach, difference-in-differences analysis, alternative measures and subsample analysis. Consistent with the notion that weak peer performance increases investors' demand for information, the relationship is more profound for firms suffering from high information externality, with weak governance and high information asymmetry. Furthermore, we find that the relationship is difficult to reconcile with the explanation of managers' herding behaviour. In addition, we show that conservative accounting information disclosure due to weak peer performance alleviates managerial bad news hoarding and information asymmetry for underperforming firms, but distorts investment decisions for outperforming firms. We highlight the spillover effect of peer performance on conservative accounting information and the related heterogeneous outcomes

A Stochastic Event-Triggered Robust Cubature Kalman Filtering Approach to Power System Dynamic State Estimation With Non-Gaussian Measurement Noises

In power system communication and control, the wide-area measurement system (WAMS) is usually adversely affected by noisy measurements and data congestion, posing great challenges to the stability and functionality of modern power grids. This study proposes a stochastic event-triggered robust dynamic state estimation (DSE) method for non-Gaussian measurement noises, using the cubature Kalman filter (CKF) technique. To reduce the computational burden and data transmission congestion resulting from centrally processing the measurement data, the proposed event-triggered robust CKF (ET-RCKF) is deployed at a local level with appropriate system formulation. The proposition of the novel robust DSE strategy is detailed in this brief, with its stability mathematically analyzed and proven, and simulation study on the IEEE 39-bus benchmark test system verifies the effectiveness of the proposed ET-RCKF approach. This novel DSE method is able to cope with non-Gaussian measurement noises and produce highly satisfactory estimation results, leading to wide applicability in real-world power system applications

Phosphorylation of mitogen-activated protein kinase in the medial prefrontal cortex and the amygdala following memory retrieval or forgetting in developing rats

We examined neuronal correlates of forgetting in rats by detection of phosphorylated mitogen-activated protein kinase (pMAPK) in the medial prefrontal cortex (mPFC) and amygdala. In Experiment 1, postnatal day (P)23 and P16 rats received paired noise CS-shock US presentations. When tested immediately after conditioning, P23 and P16 rats exhibited similar levels of conditioned fear; when tested after 2. days, however, P16 rats showed poor CS-elicited freezing relative to P23 rats. In Experiment 2, P16 and P23 rats received either paired or unpaired CS-US presentations, and then were tested 48. h later. Consistent with Experiment 1, P16 rats showed forgetting whereas P23 rats exhibited good retention at test. Additionally, unpaired groups showed poor CS-elicited freezing at test. Immunohistochemistry showed that P23 and P16 rats given paired presentations exhibited significant elevation of pMAPK-immunoreactive(ir) neurons in the amygdala compared to rats given unpaired presentations. That is, MAPK phosphorylation in the amygdala tracked learning history rather than behavioral performance at test. In contrast, only the P23-paired group showed an elevated number of pMAPK-ir neurons in mPFC, indicating that MAPK phosphorylation in the mPFC tracks memory expression. Different test-perfusion intervals were employed in Experiment 3, which showed that the developmental dissociation in the pMAPK-ir neurons observed in the mPFC in Experiment 2 was not due to age differences in the rate of phosphorylation of MAPK. These findings provide initial evidence suggesting that while the mPFC is involved in memory retrieval, MAPK phosphorylation in the amygdala may be a persisting neural signature of fear memory. © 2011 Elsevier Inc.

Establishing a role for the visual complexity of lingustic stimuli in age-related reading difficulty: Evidence from eye movements during Chinese reading

Older adults experience greater difficulty compared to young adults during both alphabetic and non-alphabetic reading. However, while this age-related reading difficulty may be attributable to visual and cognitive declines in older adulthood, the underlying causes remain unclear. With the present research, we focused on effects related to the visual complexity of written language. Chinese is ideally-suited to investigating such effects, as characters in this logographic writing system can vary substantially in complexity (in terms of number of strokes, i.e., lines and dashes) while always occupying the same square area of space, so that this complexity is not confounded with word length. Non-reading studies suggests older adults have greater difficulty than young adults when recognizing characters with high compared to low numbers of strokes. The present research used measures of eye movements to investigate adult age differences in these effects during natural reading. Young adult (18-28 years) and older adult (65+ years) participants read sentences that included one of a pair of two-character target words matched for lexical frequency and contextual predictability but composed of either high-complexity (>9 strokes) or low-complexity (<=7 strokes) characters. Typical patterns of age-related reading difficulty were observed. However, an effect of visual complexity in reading times for words was greater for the older than younger adults, due to the older readers experiencing greater difficulty identifying words containing many rather than few strokes. We interpret these findings in terms of the influence of subtle deficits in visual abilities on reading capabilties in older adulthood