Vertical Blocking Research Articles

A Federated Network Intrusion Detection System with Multi-Branch Network and Vertical Blocking Aggregation

The rapid development of cloud–fog–edge computing and mobile devices has led to massive amounts of data being generated. Also, artificial intelligence technology, like machine learning and deep learning, is widely used to mine the value of the data. Specifically, detecting attacks on the cloud–fog–edge computing system using mobile devices is essential. External attacks on network press organizations led to anomaly flow in network traffic. The network intrusion detection system (NIDS) has been an effective method for detecting anomaly flow. However, the NIDS is hard to deploy in distributed networks because network flow data are kept private. Existing methods cannot obtain an accurate NIDS under such a federated scenario. To construct an NIDS while preserving data privacy, we propose a combined model that integrates binary classifiers into a whole network based on simple classifier networks to specify the type of attack on anomalous data and offer instruction to other security system components. We also introduce federated learning (FL) methods into our system and design a new aggregation algorithm named vertical blocking aggregation (FedVB) according to our model structure. Our experiments demonstrate that our system can be more effective than simple multi-classifiers in terms of accuracy and significantly reduce communication and computation overhead when applying FedVB.

The deep background of large-scale, Mesozoic Cu-Au-W metallogenesis in northeastern South China: Constraints from Yingshan-Changshan wide-angle seismic reflection/refraction data

To investigate the geodynamic processes of Mesozoic large-scale mineralization in South China, we deployed a 350-km-long, wide-angle seismic reflection/refraction sounding profile between Yingshan in Hubei and Changshan in Zhejiang. This profile traverses the Cu-Au metallogenic belt in the middle and lower reaches of the Yangtze River (YMB), the Jiangnan W-polymetal metallogenic belt (JNMB), and the Qinhang Cu-polymetal metallogenic belt (QHMB). Our imaging results reveal various interesting velocity features along the profile. (1) The velocity structure is characterized by vertical layering and horizontal blocking; (2) the YMB is marked by high velocity and high Vp/Vs ratios in general with a significantly uplifted Moho interface and a thin crust of ∼31 km, and the lower crust contains high-velocity anomalies and has the characteristics of a crust-mantle transition zone; (3) the JNMB is bounded by the Jiangnan fault and Jingdezhen-Huangshan fault and has low-velocity anomalies and low Vp/Vs ratios; and (4) the QHMB is characterized by high-velocity anomalies and high Vp/Vs ratios. The high-velocity anomalies in the YMB and QHMB represent relatively Cu-Au-rich mafic juvenile lower crust. The formation of this kind of crust is considered to be related to mantle-derived magma underplating or residues of Neoproterozoic oceanic crustal materials, and it also provided sources for large-scale Cu-Au mineralization in the Mesozoic. The JNMB has features similar to those of ancient crusts enriched in W-Sn, the partial melting of which played a leading role in the formation of the superlarge W deposits in this belt. Considering these results and other regional geological data, we propose that a large-scale oblique upwelling of the asthenosphere along the collisional belt of the Yangtze and Cathaysia blocks during the Mesozoic was the deep driving mechanism for the explosive mineralization of Cu, Au, and W in northeastern South China. The boundaries of the blocks or terrains and discontinuities of the lithosphere were the main channels for deep heat and magmas and therefore controlled the spatial distribution of the metallogenic belt.

Tortuous flow path design for leakage reduction of labyrinth seal

This study proposes a new seal design to reduce the leakage in turbomachines. On the basis of the conventional labyrinth seal, two vertical blocking walls are added on the rotor, and one horizontal blocking wall is added on the upstream seal tooth and downstream seal tooth. In the new seal, a tortuous flow path is generated, and many vortexes appear. The new seal increases the resistance to the leakage fluid and kinetic energy dissipation. After the comparison of the leakage between the specially designed new seal and conventional labyrinth seal, it can be found that the specially designed new seal yields a reduction in the leakage of 42.7~43.6%.

GaN HEMTs on low resistivity Si substrates with thick buffer layers for RF signal amplification and power conversion

We report GaN high-electron-mobility transistors (HEMTs) with a thick (7.7 µm) GaN buffer on a Czochralski low resistivity Si (LRS) substrate. The GaN HEMTs exhibit high performance for both radio-frequency (RF) amplification and power conversion. The thick GaN buffer was grown by means of vacancy engineering, delivering a low dislocation density of ∼1.6 × 108 cm−2, contributing to suppressed RF signal coupling to the lossy Si substrate and a high vertical voltage blocking capability. For RF performance, GaN HEMTs with a 650 nm gate exhibit an fT/fMAX value of 25.1/32.3 GHz and a maximum output power POUT of 2.2 W/mm at 4 GHz with a drain voltage VDS of 20 V, which is comparable with the performance of RF GaN HEMTs on a high-resistivity silicon substrate without the existence of the field plate. For power performance, the vertical breakdown voltage of the wafer is 1160 V, and the three-terminal lateral breakdown voltage is 885 V in a GaN HEMT with a gate-to-drain distance of 8 µm. The thick GaN layer on the LRS substrate scheme thus provides a compelling platform for monolithic integration of high-performance RF devices and high-voltage power devices.

A Study on the Efficiency of Vertical Non-Combustible Blocking for External Fire Spread of EIFS with Combustible Insulation in Piloti Building

The requirements for exterior finishing materials have been substantially established recently. After a fire at an apartment building in Uijeongbu City, fire safety requirements for exterior finishing materials used in the buildings that have six and more stories or are taller than 22 meters were specified in 2015, and three and more stories or are taller than 9 meters were specified in 2019. However, the buildings built before that may not accomplish the safety requirements and thus have fire safety problem. This study suggests a method for partially reinforcing the Exterior Insulation Finishing System (EIFS) of buildings to enhance the fire safety. EIFS specimens whose walls on the pilotis were reinforced with a mineral insulation material, were tested in accordance with BS 8414-1. The result showed that fire spread was delayed more than 9 min when compared with an EIFS specimen without reinforcement.

Influences of delta sandstone architecture on waterflooding sweep characteristics: A case study of layer J-II of Kumkol South oilfield in South Turgay Basin, Kazakstan

Abstract Taking layer J-II of Upper Jurassic of Kumkol South oilfield in South Turgay Basin, Kazakstan as an example, the article studied the architecture characteristics and heterogeneity of delta sandstones, and determined the influence of sandstone architecture on waterflooding sweep characteristics using fine characterization of sandstones, comprehensive interpretation of waterflooded layers, statistical analysis of production and injection profiles, reservoir numerical simulation methods. The result shows that the delta sandstones have a complex architecture of mosaic structure with mudstone baffles and mud-interbeds, and the sandstone architecture controls the sweeping characteristics of waterflood: due to impermeable or low permeable boundaries between single sand bodies, and lateral and vertical blocking of underwater distributaries bay mudstone, sands in delta have very complicated architecture, and the injected water flows priorly into underwater distributaries channel sand and estuary bar sand with better physical properties, making these two types of sands suffer stronger warterflooding, and have higher recovery degree and better waterflooding sweep effect in plane. Inside single sand bodies, on the one hand, underwater distributaries channel sand and estuary bar sand have high vertical producing degree and good waterflooding sweep effect because mud interbeds in the sands have vertical blocking and shunt effect on injected water; on the other hand, these two types of sands have inhomogeneous waterflood sweeping because of large permeability difference and high development of dominant water channels. In contrast, made up of thin homogeneous fine sand with poor physical properties, lateral sheet sand often has even water-flooding and poor waterflooding sweep effect.

Efficiency of TLDs with bottom-mounted baffles in suppression of structural responses when subjected to harmonic excitations

Tuned Liquid Dampers (TLDs) provide low damping when it comes to deep water condition, and that not all water depth is mobilized in energy dissipation. This research focussed on a method to improve the efficiency of TLDs with deep water condition. Several bottom-mounted baffles were installed inside a TLD and the dynamic characteristics of modified TLDs together with their effect on the vibration control of a SDOF structure were studied experimentally. A series of free vibration and harmonic forced vibration tests were carried out. The controlling parameter in the conducted tests was the Vertical Blocking Ratio (VBR) of baffles. Results indicated that increase in VBR decreases the natural frequency of TLD and increases its damping ratio. It was found that the VBR range of 10% to 30% reduced response of the structure significantly. The modified TLD with the VBR of 30% showed the best performance when reduction in structural responses under harmonic excitations were compared.

Relationship between sandstone architecture and remaining oil distribution pattern: A case of the Kumkol South oilfield in South Turgay Basin, Kazakstan

Abstract Taking the Kumkol South oilfield in South Turgay Basin, Kazakstan as an example, this article summarizes the controlling pattern of different types of sandstone architecture on remaining oil distribution through examining architecture characteristics, development effect and remaining oil distribution characteristics of meandering river sandstone, braided river sandstone and delta sandstone. The braided river sandstone has simple architecture which is extensive connecting body with horizontal mud-interlayers. The water flooding sweeps evenly and the edge-bottom water drives quickly in braid river sandstone. And the remaining oil distribution pattern of braid river sandstone is the vertical blocking pattern controlled by the horizontal mud-interlayers at the high water cut stage. The meandering river sandstone is a half connecting body with abandoned channels and the lateral accretion mud-interlayers, so the injected water sweeps through the middle and lower parts of point bar sandstone, and its remaining oil distribution pattern is the horizontal blocking pattern controlled by abandoned channels and the lateral accretion mud-interlayers. The delta sandstone has a complex architecture of mosaic structure with abundant horizontal and vertical mud-interlayers and mud-interbeds, in which the injected water sweeps along preferential path, with low sweeping efficiency, and the remaining oil distribution pattern is the complex blocking pattern controlled by horizontal and vertical mud-interlayers and mud-interbeds. The results show that different techniques should be used to enhance the remaining oil recovery because of the different remaining oil distribution patterns in different kind of sand bodies.

Characterization of AlN/AlGaN/GaN:C heterostructures grown on Si(111) using atom probe tomography, secondary ion mass spectrometry, and vertical current-voltage measurements

Complementary studies of atom probe tomography, secondary ion mass spectrometry, and vertical current-voltage measurements are carried out in order to unravel the influence of C-doping of GaN on the vertical leakage current of AlN/AlGaN/GaN:C heterostructures. A systematic increment of the vertical blocking voltage at a given current density is observed in the structures, when moving from the nominally undoped conditions—corresponding to a residual C-background of ∼1017 cm−3—to a C-content of ∼1019 cm−3 in the GaN layer. The value of the vertical blocking voltage saturates for C concentrations higher than ∼1019 cm−3. Atom probe tomography confirms the homogeneity of the GaN:C layers, demonstrating that there is no clustering at C-concentrations as high as 1020 cm−3. It is inferred that the vertical blocking voltage saturation is not likely to be related to C-clustering.

Patent claims and economic growth

This study introduces a blocking patent on horizontal R&D into the endogenous growth model of Chu et al. (2012), which features a blocking patent on vertical R&D. Results show that strengthening patent protection on horizontal R&D promotes vertical innovation (quality improvement) but hinders horizontal innovation (variety expansion). This effect of a horizontal blocking patent on directionality of innovation is opposite to that of the vertical blocking patent analyzed by Chu et al. (2012). Results also show that under mild conditions, strengthening a blocking patent on horizontal innovation as well as on vertical innovation can increase economic growth and social welfare.

Vertical Blocking in Cotton Cultivar Performance Trials in North Carolina

The three principles of experimental design—randomization, replication, and blocking—have been followed routinely in field experiments. This paper addresses issues of blocking in conducting cultivar performance trials. Most agronomists design (block) their trials by considering the slope of the field at most. However, the direction of field variation might not always follow the slope of the field. Blocking in the direction of field operations is advocated. The objective of this study was to compare precision between three years of horizontal blocking with three years of vertical blocking in North Carolina Official Cotton Variety Trials. No significant difference in precision was found between the two blocking arrangements. However, the standard analysis of variance of a randomized complete block design revealed that vertical blocking produced a larger standard error than when the tests were blocked horizontally. Although vertical blocking results in increased spatial distance, the use of a spatial analysis package should mitigate this problem.

Fabrication of current confinement aperture structure by transforming a conductive GaN:Si epitaxial layer into an insulating GaOx layer.

We report here a simple and robust process to convert embedded conductive GaN epilayers into insulating GaOx and demonstrate its efficacy in vertical current blocking and lateral current steering in a working LED device. The fabrication processes consist of laser scribing, electrochemical (EC) wet-etching, photoelectrochemical (PEC) oxidation, and thermal oxidization of a sacrificial n(+)-GaN:Si layer. The conversion of GaN is made possible through an intermediate stage of porosification where the standard n-type GaN epilayers can be laterally and selectively anodized into a nanoporous (NP) texture while keeping the rest of the layers intact. The fibrous texture of NP GaN with an average wall thickness of less than 100 nm dramatically increases the surface-to-volume ratio and facilitates a rapid oxidation process of GaN into GaOX. The GaOX aperture was formed on the n-side of the LED between the active region and the n-type GaN layer. The wavelength blueshift phenomena of electroluminescence spectra is observed in the treated aperture-emission LED structure (441.5 nm) when compared to nontreated LED structure (443.7 nm) at 0.1 mA. The observation of aperture-confined electroluminescence from an InGaN LED structure suggests that the NP GaN based oxidation will play an enabling role in the design and fabrication of III-nitride photonic devices.

Vertical Blocking Voltage Improvement of GaN HEMT Structures on n-SiC by Pre-Epitaxial Substrate Implantation

To overcome the use of expensive semi-insulating SiC substrates, we developed a method to increase the vertical blocking strength of n-SiC by argon implantation prior to the high temperature epitaxial growth (1150°C) of the (Al)GaN layers. We superimpose 4 argon implantation energies (30 keV + 60 keV + 180 keV + 360 keV) to a total maximal concentration of 1·1018 atoms/cm3 and observed a 90 V - 100 V increase of the vertical blocking strength by this method. Implantation profile and dose dependencies are studied showing that the results could be related to an increased substrate resistance achieved by implantation. HRXRD analysis shows that the defect density in the GaN buffer is not increased by substrate implantation.

Improving Breakdown Behavior by Substrate Bias in a Novel Double Epi-layer Lateral Double Diffused MOS Transistor

A new lateral double diffused MOS (LDMOS) transistor with a double epitaxial layer formed by an n-type substrate and a p-type epitaxial layer is reported (DEL LDMOS). The mechanism of the improved breakdown characteristic is that the high electric field around the drain is reduced by substrate reverse bias, which causes the redistribution of the bulk electric field in the drift region, and the vertical blocking voltage is shared by the drain side and the source side. The numerical results indicate that the trade-off between breakdown voltage and on-resistance of the proposed device is improved greatly in comparison to that of the conventional LDMOS.

A novel high voltage LIGBT with an n-region in p-substrate

A novel 4 μm thickness drift region lateral insulated gate bipolar transistor with a floating n-region (NR-LIGBT) in p-substrate is proposed. Due to the field modulation from the n-region, the vertical blocking capability is enhanced and the breakdown voltage is improved significantly. Low area cost, high current capability and short turn-off time are achieved because of the high average electric field per micron. Simulation results show that the blocking capability of the new LIGBT increases by about 58% when compared with the conventional LIGBT (C-LIGBT) for the same 100 μm drift region length. Furthermore, the turn-off time is shorter than that of the conventional LIGBT for nearly same blocking capability.

No-reference image quality metric based on image classification

In this article, we present a new no-reference (NR) objective image quality metric based on image classification. We also propose a new blocking metric and a new blur metric. Both metrics are NR metrics since they need no information from the original image. The blocking metric was computed by considering that the visibility of horizontal and vertical blocking artifacts can change depending on background luminance levels. When computing the blur metric, we took into account the fact that blurring in edge regions is generally more sensitive to the human visual system. Since different compression standards usually produce different compression artifacts, we classified images into two classes using the proposed blocking metric: one class that contained blocking artifacts and another class that did not contain blocking artifacts. Then, we used different quality metrics based on the classification results. Experimental results show that each metric correlated well with subjective ratings, and the proposed NR image quality metric consistently provided good performance with various types of content and distortions.

No-Reference JPEG image quality assessment based on Visual sensitivity

No-Reference JPEG image quality assessment based on Visual sensitivity

Nonparametric estimation over shrinking neighborhoods: Superefficiency and adaptation

A theory of superefficiency and adaptation is developed under flexible performance measures which give a multiresolution view of risk and bridge the gap between pointwise and global estimation. This theory provides a useful benchmark for the evaluation of spatially adaptive estimators and shows that the possible degree of superefficiency for minimax rate optimal estimators critically depends on the size of the neighborhood over which the risk is measured. Wavelet procedures are given which adapt rate optimally for given shrinking neighborhoods including the extreme cases of mean squared error at a point and mean integrated squared error over the whole interval. These adaptive procedures are based on a new wavelet block thresholding scheme which combines both the commonly used horizontal blocking of wavelet coefficients (at the same resolution level) and vertical blocking of coefficients (across different resolution levels).

Low threshold InGaAs strained quantum well laser with lateral npn current blocking structure grown by molecular beam epitaxy

A sophisticated current confinement structure using the amphoteric nature of MBE grown Si-doped GaAs and AlGaAs is demonstrated for an index-guided InGaAs strained quantum well laser. Lateral and vertical npn current blocking layers were formed for the first time by a selfaligned process. Devices showed threshold current of 10 mA and total slope efficiency of 0.56 under room temperature CW operation.