16 research outputs found
LA-GRU: Building Combined Intrusion Detection Model Based on Imbalanced Learning and Gated Recurrent Unit Neural Network
The intrusion detection models (IDMs) based on machine learning play a vital role in the security protection of the network environment, and, by learning the characteristics of the network traffic, these IDMs can divide the network traffic into normal behavior or attack behavior automatically. However, existing IDMs cannot solve the imbalance of traffic distribution, while ignoring the temporal relationship within traffic, which result in the reduction of the detection performance of the IDM and increase the false alarm rate, especially for low-frequency attacks. So, in this paper, we propose a new combined IDM called LA-GRU based on a novel imbalanced learning method and gated recurrent unit (GRU) neural network. In the proposed model, a modified local adaptive synthetic minority oversampling technique (LA-SMOTE) algorithm is provided to handle imbalanced traffic, and then the GRU neural network based on deep learning theory is used to implement the anomaly detection of traffic. The experimental results evaluated on the NSL-KDD dataset confirm that, compared with the existing state-of-the-art IDMs, the proposed model not only obtains excellent overall detection performance with a low false alarm rate but also more effectively solves the learning problem of imbalanced traffic distribution
Effects of Anthropogenic Disturbances and Climate Change on Riverine Dissolved Inorganic Nitrogen Transport
Abstract Nitrogen (N) transport from land to rivers, estuaries, and coastal marine systems has been markedly altered by anthropogenic and climatic drivers over recent decades. In this study, a riverine N transport scheme considering anthropogenic N discharge and water regulation was incorporated into the Land Surface Model of the Chinese Academy of Sciences (CASāLSM). Seven groups of simulations using the developed model at the global scale for the period of 1981ā2010 were conducted to investigate the effects of anthropogenic disturbances and climate change on riverine dissolved inorganic nitrogen (DIN) transport. It was shown that fertilization and point source pollution have enhanced the DIN fluxes in rivers across the world, especially in western Europe and eastern China. The DIN exports were significantly reduced due to retention by reservoirs and the withdrawal of surface water and groundwater, with a retention efficiency of 50ā70%. Climate variability and trends increased or decreased the riverine DIN fluxes depending on the specific hydroclimatic conditions. We further analyzed the contributions of climatic and anthropogenic changes to the riverine DIN changes in four major rivers. The riverine DIN exports in the Mississippi River Basin were affected primarily by fertilization, while the changes in DIN exports of the Danube were dominated by point source pollution and water regulation. The Yangtze River in China was seriously affected by both fertilization and point source pollution, and water regulation played a significant role in reducing DIN exports. Climate variability was the primary factor explaining the interannual variability of DIN exports
Growth of Highly Oriented Ultrathin Crystalline Organic Microstripes: Effect of Alkyl Chain Length
The growth of organic semiconductor
with controllable morphology
is a crucial issue for achieving high-performance devices. Here we
present the systematic study of the effect of the alkyl chain attached
to the functional entity on controlling the growth of oriented microcrystals
by dip-coating. Alkylated DTBDT-based molecules with variable chain
lengths from <i>n</i>-butyl to <i>n</i>-dodecyl
formed into one-dimensional micro- or nanostripe crystals at different
pulling speeds. The alignment and ordering are significantly varied
with alkyl chain length, as is the transistor performance. Highly
uniform oriented and higher-molecular-order crystalline stripes with
improved field-effect mobility can be achieved with an alkyl-chain
length of around 6. We attribute this effect to the alkyl-chain-length-dependent
packing, solubility, and self-assembly behavior
Survival Prediction in High-grade Osteosarcoma Using Radiomics of Diagnostic Computed Tomography
The poor 5-year survival rate in high-grade osteosarcoma (HOS) has not been increased significantly over the past 30āÆyears. This work aimed to develop a radiomics nomogram for survival prediction at the time of diagnosis in HOS.In this retrospective study, an initial cohort of 102 HOS patients, diagnosed from January 2008 to March 2011, was used as the training cohort. Radiomics features were extracted from the pretreatment diagnostic computed tomography images. A radiomics signature was constructed with the lasso algorithm; then, a radiomics score was calculated to reflect survival probability by using the radiomics signature for each patient. A radiomics nomogram was developed by incorporating the radiomics score and clinical factors. A clinical model was constructed by using clinical factors only. The models were validated in an independent cohort comprising 48 patients diagnosed from April 2011 to April 2012. The performance of the nomogram was assessed with respect to its calibration, discrimination, and clinical usefulness. KaplanāMeier survival analysis was performed.The radiomics nomogram showed better calibration and classification capacity than the clinical model with AUC 0.86 vs. 0.79 for the training cohort, and 0.84 vs. 0.73 for the validation cohort. Decision curve analysis demonstrated the clinical usefulness of the radiomics nomogram. A significant difference (p-value <.05; log-rank test) was observed between the survival curves of the nomogram-predicted survival and non-survival groups. The radiomics nomogram may assist clinicians in tailoring appropriate therapy
Nitroacetylacetone as a Cofuel for the Combustion Synthesis of High-Performance IndiumāGalliumāZinc Oxide Transistors
Thin-film
combustion synthesis has been utilized for the fabrication
of solution processed high-performance metal-oxide thin-film transistors
(MOTFTs) at lower temperatures than conventional solāgel processes.
The fuel-oxidizer ensemble in the MO precursor solution/film plays
an important role in achieving high-efficiency and low-residual combustion
byproducts. However, unlike conventional bulk combustion, only a very
limited number of thin-film fuels have been investigated. Here we
report the use of an efficient new cofuel, 3-nitroacetylacetone (NAcAcH),
incorporating a āNO<sub>2</sub> group, for the combustion synthesis
of display-relevant indiumāgalliumāzinc-oxide (IGZO)
thin films. Compared to the traditional acetylacetone (AcAcH) fuel,
a higher enthalpy of combustion (988.6 vs 784.4 J/g) and a lower ignition
temperature (107.8 vs 166.5 Ā°C) are achieved for NAcAcH-based
formulations. The resulting NAcAcH-derived IGZO TFTs exhibit far higher
average electron mobilities (5.7 cm<sup>2</sup> V<sup>ā1</sup> s<sup>ā1</sup>) than AcAcH-derived TFTs (2.7 cm<sup>2</sup> V<sup>ā1</sup> s<sup>ā1</sup>). More importantly,
when combining AcAcH with NAcAcH as cofuels in an optimal molar ratio
of 1.5:0.5, an even larger TFT electron mobility (7.5 cm<sup>2</sup> V<sup>ā1</sup> s<sup>ā1</sup>) and more stable devices
are achieved. Comprehensive IGZO precursor/film analysis and characterization
by differential scanning calorimetry (DSC), thermogravimetric analysis
(TGA), X-ray photoelectron spectroscopy (XPS), grazing incidence X-ray
diffraction (GIXRD), and X-ray reflectivity (XRR) explain the basis
of the film microstructure and TFT performance trends