Adversarial Dropout for Supervised and Semi-supervised Learning

Recently, the training with adversarial examples, which are generated by adding a small but worst-case perturbation on input examples, has been proved to improve generalization performance of neural networks. In contrast to the individually biased inputs to enhance the generality, this paper introduces adversarial dropout, which is a minimal set of dropouts that maximize the divergence between the outputs from the network with the dropouts and the training supervisions. The identified adversarial dropout are used to reconfigure the neural network to train, and we demonstrated that training on the reconfigured sub-network improves the generalization performance of supervised and semi-supervised learning tasks on MNIST and CIFAR-10. We analyzed the trained model to reason the performance improvement, and we found that adversarial dropout increases the sparsity of neural networks more than the standard dropout does.Comment: submitted to AAAI-1

Effect of Surface Waves on Air–Sea Momentum Exchange. Part I: Effect of Mature and Growing Seas

The effect of surface waves on air–sea momentum exchange over mature and growing seas is investigated by combining ocean wave models and a wave boundary layer model. The combined model estimates the wind stress by explicitly calculating the wave-induced stress. In the frequency range near the spectral peak, the NOAA/ NCEP surface wave model WAVEWATCH-III is used to estimate the spectra, while the spectra in the equilibrium range are determined by an analytical model. This approach allows for the estimation of the drag coefficient and the equivalent surface roughness for any surface wave fields. Numerical experiments are performed for constant winds from 10 to 45 m s−1 to investigate the effect of mature and growing seas on air–sea momentum exchange. For mature seas, the Charnock coefficient is estimated to be about 0.01 ∼ 0.02 and the drag coefficient increases as wind speed increases, both of which are within the range of previous observational data. With growing seas, results for winds less than 30 m s−1 show that the drag coefficient is larger for younger seas, which is consistent with earlier studies. For winds higher than 30 m s−1, however, results show a different trend; that is, very young waves yield less drag. This is because the wave-induced stress due to very young waves makes a small contribution to the total wind stress in very high wind conditions

Effect of surface waves on Charnock coefficient under tropical cyclones

The dependence of the air‐sea momentum flux on surface wave fields is investigated at very high winds under tropical cyclones. A coupled wave‐wind model is applied to estimate the momentum flux under ten hurricanes in the western Atlantic Ocean during 1998–2003. The model explicitly calculates the wave‐induced stress vector and the total wind stress vector from a given wind speed vector and a calculated wave spectrum. It is found that the neutral drag coefficient levels off at high wind speeds under tropical cyclones, being consistent with recent observations and previous modeling studies. The most important finding of this study is that the Charnock coefficient is mainly determined by two parameters: the input wave age (wave age determined by the peak frequency of wind energy input) and the wind speed, regardless of the complexity of the wave field under a real hurricane, and that the Charnock coefficient increases with the input wave age at very high winds

Effect of Surface Waves on Air–Sea Momentum Exchange. Part II: Behavior of Drag Coefficient under Tropical Cyclones

Present parameterizations of air–sea momentum flux at high wind speed, including hurricane wind forcing, are based on extrapolation from field measurements in much weaker wind regimes. They predict monotonic increase of drag coefficient (Cd) with wind speed. Under hurricane wind forcing, the present numerical experiments using a coupled ocean wave and wave boundary layer model show that Cd at extreme wind speeds strongly depends on the wave field. Higher, longer, and more developed waves in the right-front quadrant of the storm produce higher sea drag; lower, shorter, and younger waves in the rear-left quadrant produce lower sea drag. Hurricane intensity, translation speed, as well as the asymmetry of wind forcing are major factors that determine the spatial distribution of Cd. At high winds above 30 m s−1, the present model predicts a significant reduction of Cd and an overall tendency to level off and even decrease with wind speed. This tendency is consistent with recent observational, experimental, and theoretical results at very high wind speeds

Role of Caffeic Acid on Collagen Production in Nasal Polyp-Derived Fibroblasts

ObjectivesCaffeic acids are known to have anti-oxidant, anti-inflammatory, immunomodulatory, and tissue reparative effects. The purposes of this study were to determine the effect of caffeic acid on transforming growth factor (TGF) β1-induced myofibroblast differentiation and collagen production, and to determine whether caffeic acid is involved in the antioxidant effect in nasal polyp-derived fibroblasts (NPDFs).MethodsNPDFs were pretreated with caffeic acid (1-10 µM) for 2 hours and stimulated with TGF-β1 (5 ng/mL) for 24 hours. The expression of α-smooth muscle actin (SMA), collagen types I and III, and Nox4 mRNA was determined by a reverse transcription-polymerase chain reaction, and the expression of α-SMA protein was determined by actin ned by immunofluorescence microscopy. The amount of total soluble collagen production was analyzed by the Sircol collagen dye-binding assay. The reactive oxygen species (ROS) generated by NPDFs were determined using 2',7'-dichlorfluorescein-diacetate. siNox4 was used to determine the effect of Nox4.ResultsThe expression of α-SMA and production of collagen were significantly increased following TGF-β1 treatment. In contrast, the level of expression of α-SMA and the level of production of collagen were decreased by pretreatment with caffeic acid. The activation of Nox4 and the subsequent production of ROS were also reduced by pretreatment with caffeic acid. The expression of α-SMA was prevented by inhibition of ROS generation with siNox4.ConclusionCaffeic acid may inhibit TGF-β1-induced differentiation of fibroblasts into myofibroblasts and collagen production by regulating ROS

Observation of In-Plane Magnetic Field Induced Phase Transitions in FeSe

We investigate thermodynamic properties of FeSe under in-plane magnetic fields using torque magnetometry, specific heat, and magnetocaloric measurements. Below the upper critical field Hc2, we observed the field induced anomalies at H1 ∼ 15 T and H2 ∼ 22 T near H ∥ ab and below a characteristic temperature T* ∼ 2 K. The transition magnetic fields H1 and H2 exhibit negligible dependence on both temperature and field orientation. This contrasts to the strong temperature and angle dependence of Hc2, suggesting that these anomalies are attributed to the field induced phase transitions, originating from the inherent spin-density-wave instability of quasipaticles near the superconducting gap minima or possible Flude-Ferrell-Larkin-Ovchinnikov state in the highly spin-polarized Fermi surfaces. Our observations imply that FeSe, an atypical multiband superconductor with extremely small Fermi energies, represents a unique model system for stabilizing unusual superconducting orders beyond the Pauli limit