A novel time-frequency slice extraction method for target recognition and local enhancement of non-stationary signal features.

Blind deconvolution can remove the effects of complex paths and extraneous disturbances, thus recovering simple features of the original fault source, and is used extensively in the field of fault diagnosis. However, it can only identify and extract the statistical mean of the fault impact features in a single domain and is unable to simultaneously highlight the local features of the signal in the time-frequency domain. Therefore, the extraction effect of weak fault signals is generally not ideal. In this paper, a new time-frequency slice extraction method is proposed. The method first computes a high temporal resolution spectrum of the signal by short-time Fourier transform to obtain multiple frequency slices with distinct temporal waveforms. Subsequently, the constructed harmonic spectral feature index is used to quantify and target the intensity of feature information in each frequency slice and enhance their fault characteristics using maximum correlation kurtosis deconvolution. Enhancing the local features of selected frequency slice clusters can reduce noise interference and obtain signal components with more obvious fault signatures. Finally, the validity of the method was confirmed by a simulated signal and fault diagnosis of the rolling bearing outer and inner rings was accomplished sequentially. Compared with other common deconvolution methods, the proposed method obtains more accurate and effective results in identifying fault messages.

Functional Brain Network Analysis of Knowledge Transfer While Engineering Problem-Solving.

As a complex cognitive activity, knowledge transfer is mostly correlated to cognitive processes such as working memory, behavior control, and decision-making in the human brain while engineering problem-solving. It is crucial to explain how the alteration of the functional brain network occurs and how to express it, which causes the alteration of the cognitive structure of knowledge transfer. However, the neurophysiological mechanisms of knowledge transfer are rarely considered in existing studies. Thus, this study proposed functional connectivity (FC) to describe and evaluate the dynamic brain network of knowledge transfer while engineering problem-solving. In this study, we adopted the modified Wisconsin Card-Sorting Test (M-WCST) reported in the literature. The neural activation of the prefrontal cortex was continuously recorded for 31 participants using functional near-infrared spectroscopy (fNIRS). Concretely, we discussed the prior cognitive level, knowledge transfer distance, and transfer performance impacting the wavelet amplitude and wavelet phase coherence. The paired t-test results showed that the prior cognitive level and transfer distance significantly impact FC. The Pearson correlation coefficient showed that both wavelet amplitude and phase coherence are significantly correlated to the cognitive function of the prefrontal cortex. Therefore, brain FC is an available method to evaluate cognitive structure alteration in knowledge transfer. We also discussed why the dorsolateral prefrontal cortex (DLPFC) and occipital face area (OFA) distinguish themselves from the other brain areas in the M-WCST experiment. As an exploratory study in NeuroManagement, these findings may provide neurophysiological evidence about the functional brain network of knowledge transfer while engineering problem-solving.

Chinese carless young drivers' self-reported driving behavior and simulated driving performance.

OBJECTIVE: Carless young drivers refers to those drivers aged between 18 and 25 years who have a driver's license but seldom have opportunities to practice their driving skills because they do not have their own cars. Due to China's lower private car ownership, many young drivers become carless young drivers after licensure, and the safety issue associated with them has raised great concern in China. This study aims to provide initial insight into the self-reported driving behaviors and simulated driving performance of Chinese carless young drivers. METHODS: Thirty-three carless young drivers and 32 young drivers with their own cars (as a comparison group) participated in this study. A modified Driver Behavior Questionnaire (DBQ) with a 4-factor structure (errors, violations, attention lapses, and memory lapses) was used to study carless young drivers' self-reported driving behaviors. A simulated driving experiment using a low-cost, fixed-base driving simulator was conducted to measure their simulated driving performance (errors, violations, attention lapses, driving maintenance, reaction time, and accidents). RESULTS: Self-reported DBQ outcomes showed that carless young drivers reported similar errors, more attention lapses, fewer memory lapses, and significantly fewer violation behaviors relative to young drivers with their own cars, whereas simulated driving results revealed that they committed significantly more errors, attention lapses, and violation behaviors than the comparison group. Carless young drivers had a lower ability to maintain the stability of speed and lane position, drove more cautiously approaching and passing through red traffic lights, and committed more accidents during simulated driving. A tendency to speed was not found among carless young drivers; their average speed and speeding frequency were all much lower than that of the comparison group. Lifetime mileage was the only significant predictor of carless young drivers' self-reported violations, simulated violations, speed, and reaction time, whereas no significant predictor was found for young drivers with their own cars. CONCLUSIONS: Carless young drivers had poorer driving performance and were more overconfident of their self-reported driving skills compared to those young drivers with greater access to vehicles. Given that the lifetime mileage positively predicted the simulated violations measure of carless young drivers, immediate interventions are needed to help them increase driving exposure and gain driving experience gradually before moving to more challenging on-road driving tasks. Supplemental materials are available for this article.

An application of the driver behavior questionnaire to Chinese carless young drivers.

OBJECTIVE: Carless young drivers refers to those drivers aged between 18 and 25 years who have a driver's license but seldom have opportunities to practice their driving skills because they do not have their own cars. Due to China's lower private car ownership, many young drivers turn into carless young drivers after licensure, and the safety issue associated with them has become a matter of great concern in China. Because few studies have examined the driving behaviors of these drivers, this study aims to utilize the Driver Behavior Questionnaire (DBQ) to investigate the self-reported driving behaviors of Chinese carless young drivers. METHODS: A total of 523 Chinese carless young drivers (214 females, 309 males) with an average age of 21.91 years completed a questionnaire including the 27-item DBQ and demographics. The data were first randomized into 2 subsamples for factor analysis and then combined together for the following analyses. Both an exploratory factor analysis (EFA, n = 174) and a confirmatory factor analysis (CFA, n = 349) were performed to investigate the factor structure of the DBQ. Correlation analysis was conducted to examine the relationships between the demographics and the DBQ scales' variables. Multivariate linear regression and logistic regression were performed to investigate the prediction of the DBQ scales and crash involvement in the previous year. RESULTS: The EFA produced a 4-factor structure identified as errors, violations, attention lapses, and memory lapses, and the CFA revealed a good model fit after the removal of one item with a low factor loading and the permission of the error covariance between some items. The Chinese carless young drivers reported a comparatively low level of aberrant driving behaviors. The 3 most frequently reported behaviors were all lapses and the 3 least were all violations. Gender was the only significant predictor of the 2 lapses scales and lifetime mileage was the only significant predictor of the violations scale. Only the violations factor was found to be significantly predictive of crash involvement in the previous year. CONCLUSIONS: The current study provides evidence that the DBQ can successfully be utilized to examine the self-reported driving behaviors of Chinese carless young drivers. However, the factor structure as well as the level of reported aberrant driving behaviors suggests that Chinese carless young drivers are a special population and thus should be treated differently when interventions are performed. Supplemental materials are available for this article.

Pressure thresholds of the human foot: measurement reliability and effects of stimulus characteristics.

Information related to reliable values of discomfort thresholds can help to improve the designs of various products. This study aimed to investigate the measurement reliabilities associated with pressure thresholds, while determining the effects of stimulus characteristics (stimulus area, indentation speed) of the human foot. An indentation apparatus was used with four sizes of indentation probes and three indentation speeds. In total, 13 locations on the right foot of 10 male and 10 female participants were tested to determine the pressure discomfort thresholds (PDT) and pressure pain thresholds (PPT). Results show that the tests had very good measurement reliability with intra-class correlations (ICC) greater than 0.8 for the PPT measurements and acceptable reliability (most ICC > 0.75, with a few between 0.5 and 0.75) for the PDT measurements, demonstrating that participants are capable of judging their pain and discomfort thresholds. Pressure sensitivity differs across locations of the foot, with the medial plantar arch of the foot being the most sensitive, followed by the dorsal surface of the foot. The heel area was the least sensitive. PPT and PDT are dependent on the stimulus characteristics of the area and the speed of indentation. A smaller area has a higher PPT and PDT, indicating significant effects of spatial summation. The increase of PDT and PPT at higher speeds may be partially explained by the increase in stiffness because foot tissue exhibits viscoelastic properties. The findings can have a significant impact on the design of footwear and other accessories for improved foot health and comfort. Statement of Relevance: This study investigated the threshold measurement reliability while determining the pressure sensitivity on the surface of the foot with varying stimulus characteristics. The findings may be very useful in the design of footwear and other accessories for improved comfort and reduced injuries.

A bilateral integrative health-care knowledge service mechanism based on 'MedGrid'.

Current health-care organizations are encountering impression of paucity of medical knowledge. This paper classifies medical knowledge with new scopes. The discovery of health-care 'knowledge flow' initiates a bilateral integrative health-care knowledge service, and we make medical knowledge 'flow' around and gain comprehensive effectiveness through six operations (such as knowledge refreshing...). Seizing the active demand of Chinese health-care revolution, this paper presents 'MedGrid', which is a platform with medical ontology and knowledge contents service. Each level and detailed contents are described on MedGrid info-structure. Moreover, a new diagnosis and treatment mechanism are formed by technically connecting with electronic health-care records (EHRs).