Rethinking annotation granularity for overcoming deep shortcut learning: A retrospective study on chest radiographs

Deep learning has demonstrated radiograph screening performances that are comparable or superior to radiologists. However, recent studies show that deep models for thoracic disease classification usually show degraded performance when applied to external data. Such phenomena can be categorized into shortcut learning, where the deep models learn unintended decision rules that can fit the identically distributed training and test set but fail to generalize to other distributions. A natural way to alleviate this defect is explicitly indicating the lesions and focusing the model on learning the intended features. In this paper, we conduct extensive retrospective experiments to compare a popular thoracic disease classification model, CheXNet, and a thoracic lesion detection model, CheXDet. We first showed that the two models achieved similar image-level classification performance on the internal test set with no significant differences under many scenarios. Meanwhile, we found incorporating external training data even led to performance degradation for CheXNet. Then, we compared the models' internal performance on the lesion localization task and showed that CheXDet achieved significantly better performance than CheXNet even when given 80% less training data. By further visualizing the models' decision-making regions, we revealed that CheXNet learned patterns other than the target lesions, demonstrating its shortcut learning defect. Moreover, CheXDet achieved significantly better external performance than CheXNet on both the image-level classification task and the lesion localization task. Our findings suggest improving annotation granularity for training deep learning systems as a promising way to elevate future deep learning-based diagnosis systems for clinical usage.Comment: 22 pages of main text, 18 pages of supplementary table

The workload change and depression among emergency medical staff after the open policy during COVID-19: a cross-sectional survey in Shandong, China

IntroductionIn the middle of December 2022, the Chinese government adjusted the lockdown policy on coronavirus disease 2019 (COVID-19), a large number of infected patients flooded into the emergency department. The emergency medical staff encountered significant working and mental stress while fighting the COVID-19 pandemic. We aimed to investigate the workload change, and the prevalence and associated factors for depression symptoms among emergency medical staff after the policy adjustment.MethodsWe conducted a cross-sectional online survey of emergency medical staff who fought against COVID-19 in Shandong Province during January 16 to 31, 2023. The respondents’ sociodemographic and work information were collected, and they were asked to complete the 9-item Patient Health Questionnaire (PHQ-9) then. Univariate and multivariate logistic regression analyses were applied to identify the potential associated factors for major depression.ResultsNine hundred and sixteen emergency medical personnel from 108 hospitals responded to this survey. The respondents’ weekly working hours (53.65 ± 17.36 vs 49.68 ± 14.84) and monthly night shifts (7.25 ± 3.85 vs 6.80 ± 3.77) increased after the open policy. About 54.3% of the respondents scored more than 10 points on the PHQ-9 standardized test, which is associated with depressive symptoms. In univariate analysis, being doctors, living with family members aged ≤16 or ≥ 65 years old, COVID-19 infection and increased weekly working hours after the open policy were significantly associated with a PHQ-9 score ≥ 10 points. In the multivariate analysis, only increased weekly working hours showed significant association with scoring ≥10 points.ConclusionEmergency medical staff’ workload had increased after the open policy announcement, which was strongly associated with a higher PHQ-9 scores, indicating a very high risk for major depression. Emergency medical staff working as doctors or with an intermediate title from grade-A tertiary hospitals had higher PHQ-9 scores, while COVID-19 infection and weekly working hours of 60 or more after the open policy were associated with higher PHQ-9 scores for those from grade-B tertiary hospitals. Hospital administrators should reinforce the importance of targeted emergency medical staff support during future outbreaks

Numerical Investigation on the Gas Field Generated by High Pressure Gas Atomizer Focused on Physical Mechanisms of Gas Recirculation and Wake Closure Phenomenon

Physical mechanisms of gas recirculation and wake closure were investigated by modeling the gas field generated by High Pressure Gas Atomizer using computational fluid dynamics. A recirculation mechanism based on axial and radial gas pressure gradient was proposed to explain the gas recirculation. The occurrence of wake closure is regarded as a natural result when elongated wake is gradually squeezed by expansion waves of increasing intensity. An abrupt drop could be observed in the numerical aspiration pressure curve, which corresponds well with the experimental results. The axial gradient of gas density is considered as the reason that results in the sudden decrease in aspiration pressure when wake closure occurs. Lastly, it is found that a shorter protrusion length and a smaller melt tip diameter would lead to a smaller wake closure pressure, which could benefit the atomizer design to produce fine metal powder with less gas consumption

Stress Induced Hump in P-Channel Poly-Si TFTs under Dynamic Negative Bias Temperature Stress

The dynamic negative bias temperature (NBT) stress induced hump phenomenon in p-channel poly-Si TFTs has been investigated. The hump only shows up after the stress. It is found to appear along with the positive shift of device V-th and disappears after a certain stress time. The hump phenomenon is closely related to the dynamic effect, and shows the same dependency on the pulse amplitude and stress temperature with the dynamic effect. The presence of parasitic edge transistor at the channel width side is thought to be responsible for the hump phenomenon

Series Resistance Extraction in Poly-Si TFTs With Channel Length and Mobility Variations

Anew method to extract the series resistance (R(s)) of polycrystalline silicon (poly-Si) thin-film transistors (TFTs) is proposed. Different from conventional methods, this method is based on an analytical poly-Si TFT model and is insensitive to channel length and mobility variations. This method is demonstrated in both n- and p-type poly-Si TFTs

Remote Sensing Image Road Segmentation Method Integrating CNN-Transformer and UNet

Real-time and accurate road information is crucial for updating electronic navigation maps. To address the problem of low precision and poor robustness in current semantic segmentation methods for road extraction from remote sensing imagery, we proposed a UNet road semantic segmentation model based on attention mechanism improvement. First, we introduce a CNN-Transformer hybrid structure to the encoder to enhance the feature extraction capabilities of global and local details. Second, the traditional upsampling module in the decoder is replaced with a dual upsampling module to improve feature extraction capabilities and segmentation accuracy. Furthermore, the hard-swish activation function is used instead of ReLU activation function to smooth the curve, which helps to improve the generalization and non-linear feature extraction abilities and avoid gradient vanishing. Finally, a comprehensive loss function combining cross entropy and dice is used to strengthen the segmentation result constraints and further improve segmentation accuracy. Experimental validation is performed on the Ottawa Road Dataset and the Massachusetts Road Dataset. Experimental results show that compared with U-Net, PSPNet, DeepLab V3 and TransUNet networks, this algorithm is the best in terms of MIoU, MPA and F1 score. Among them, on the Ottawa road data set, the MPA of this algorithm reached 95.48%. On the Massachusetts road data set, MPA is 92.56%. This method shows good performance in road extraction

Degradation of Polycrystalline Silicon TFT CMOS Inverters under AC Operation

Degradation of polycrystalline silicon (poly-Si) thin-film transistor (TFT)-based CMOS inverters under AC operation is studied. Based on a previous drain current model of poly-Si TFTs including the kink effect, the voltage transfer characteristics of both fresh and stressed inverters are well described. It is determined that hot carrier of the n-TFT and negative bias temperature instability of the p-TFT are competing degradation mechanisms controlling the observed two-stage degradation of the inverter. Based on such mechanisms, degradation of inverter under various AC operation conditions can be qualitatively predicted. It is found that under given frequency and amplitude of the input pulse voltage, inverter's degradation can still be effectively suppressed by increasing the pulse falling time, and/or decreasing the low voltage duration

The Driving Forces of Carbon Dioxide Equivalent Emissions Have Spatial Spillover Effects in Inner Mongolia

To spatially analyze the effects of the major drivers on carbon dioxide equivalent (CO2eq) emissions in Inner Mongolia, a typical area with high CO2eq emissions in China, this paper quantitatively investigates the factors that affect county-level CO2eq emissions and the corresponding spatial mechanisms. Based on a spatial panel econometric model with related energy and economic data from 101 counties in Inner Mongolia between 2007 and 2012, four main results are obtained: (a) The CO2eq emissions in Inner Mongolia rapidly increased at an average annual growth rate of 7.27% from 2007 to 2012, increasing from 287.69 million tons to 510.47 million tons. (b) The county-level CO2eq emissions in Inner Mongolia increased, but the growth rate decreased annually. Additionally, CO2eq emissions are highly heterogeneous in the region. (c) Geographic factors were the main cause of the spatial spillover effects related to county-level CO2eq emissions. Specifically, the levels of urbanization and technological progress were conducive to CO2eq emission reductions, and the economic growth and industrial structure had the opposite effect in Inner Mongolian counties. (d) Technological progress had a significant spatial spillover effect in Inner Mongolian counties, and the effects of other factors were not significant. Implementing relevant strategies that focus on the inter-county interactions among the driving forces of CO2eq emissions could promote energy savings and emission reductions in Inner Mongolia

Hydrothermal Changes and Physicochemical Characteristics of Subtropical Subalpine Soils under Freezing and Thawing

The soil column samples were collected for indoor simulated freeze-thaw experiments to monitor the soil hydrothermal dynamics and measure the basic physicochemical properties to research the effects of freeze-thaw on the hydrothermal process of peat bog soil and its relationship with physicochemical properties. The results indicate that in the initial phase of freezing-thawing, soil water content decreases and soil temperature changes, respectively. Unfrozen water content in soil in the stable freezing period decreases sharply. Compared with the freezing period, the fluctuation of soil moisture rate during thawing is more moderate with the temperature change. Soil ammonium nitrogen content decreases with decreasing soil temperature and is significantly positively correlated with soil water content after freeze-thaw, while total phosphorus, fast-acting phosphorus, total nitrogen and nitrate have no significant correlation with soil temperature and soil moisture content after freeze-thaw

Drain voltage sweeping-induced degradation in n-type low-temperature polysilicon thin film transistors

Device degradation under the drain voltage (V-d) sweeping, where V-d lineally sweeps at a fixed gate voltage, has been investigated for n-type low-temperature (LT) polysilicon thin film transistors (TFTs). The degradation mechanism is found to be related to the dc hot carrier (HC) effect even for a sweeping time as short as similar to mu s. Since a routine device output measurement can induce significant (as large as 30\%) on-current (I-on) degradation in such LT crystallized TFTs, only by using the optimized pulse IV method can one obtain an accurate output measurement without much affecting the device under test (e.g., < 0.5\% of I-on degradation)