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The diversification and complexity of network attacks pose a serious challenge to network security and lead to the phenomenon of overlapping attributes of network attack behaviors. In this context, traditional network attack detection methods are limited to single-label learning, which cannot effectively deal with complex and diverse network attacks. To better understand the relation between network attack behaviors and improve the effect of network security protection, we first analyze the well-known network attack datasets (UNSW-NB15 and CCCS-CIC-AndMal-2020) according to the proposed multi-label metrics. Subsequently, we propose a multi-label cyber-attack detection method based on two-stage model fusion. In the first stage, a category is selected based on the analysis of multi-label metrics, and binary classification is performed. In the second stage, the binary labels generated in the first stage are added to the feature space for the multi-label categorization. Experimental results show that the two-stage model fusion method effectively improves the performance of the baseline methods. In addition, we analyze the impact of different categories and binary classification performance for the multi-label detection. The experimental results show that, theoretically, when the binary classification accuracy of Normal and Adware reaches 77% and 95% respectively, the performance of the two-stage multi-label detection method exceeds the state-of-the-art methods. This indicates the effectiveness of the two-stage strategy used in our proposed method for improving the ability of multi-label network attack detection. [ABSTRACT FROM AUTHOR]

Abstract: This paper demonstrated a novel device which was fabricated by the integration of a Fabry–Pérot cavity with waveguide photodetectors on silicon substrate. The design of this device integrates two functions on a single semiconductor chip, which is a current trend to make the compact on-chip photonic system. Due to the introduction of waveguide photodetectors, the tradeoff between efficiency and bandwidth could be improved and these two important factors could be specified almost independently. The Fabry–Pérot cavity was grown by metal–organic chemical vapor deposition (MOCVD), which was used for wavelength selectivity. The waveguide photodetector fabricated by the wet etching technique was used for light detection. The peak wavelength of the hybrid integrated device was at 1538nm. The full-width at half-maximum was about 0.3nm, and a dark current of 3.2nA was achieved at the reverse bias of 3.0V. [Copyright &y& Elsevier]

Abstract: This paper presents the design and analysis of a Si-based flat-top steep-edge RCE photodetector realized by the introduction of a two-coupled-cavity grating filter. A greatly improved rectangular spectral response which can be achieved via adjusting parameters of the filter is shown. Reflectivity spectrums of the one-cavity and the two-coupled-cavity grating filters as well as quantum efficiencies of corresponding photodetectors are simulated in detail. In the final design of the photodetector, the ratio of the linewidth at 0.9 times the peak efficiency to the linewidth at 0.1 times the peak efficiency is 0.72, 3-dB linewidth is 2.2nm, flat-top quantum efficiency is as high as 90% and sideband value is extremely low. [Copyright &y& Elsevier]

Abstract: A simulation model relying on Transfer Matrix Method is established to describe the working mechanism of an epitaxially grown multilayer Fabry–Pérot filter, which is formed by Metal-organic Chemical Vapor Deposition on GaAs substrate. By employing this model as theoretical guidance, a particular technique is proposed for the relocation of transmission characteristics (i.e. transmission peak wavelength and stop-band) of this filter. Two experiments are carried out to demonstrate this technique. In comparison with the typical one, this technique presents much higher efficiency, and consequentially is remarkably cost-effective. Moreover, this technique offers a referable methodology for the relocation of operation wavelengths of Fabry–Pérot micro-cavity-based devices. [Copyright &y& Elsevier]

Abstract: Flat-top and steep-edge spectral response of photodetectors is important for dense wavelength-division-multiplexed system. Realization of the flat-top and steep-edge response is very challenging. In the last two decades many methods have been proposed, but the spectral response linewidth is not acceptable to wavelength-division-multiplexes system. In this paper a novel RCE photodetector with flat-top and steep-edge spectral response is presented. Using the step shaped structure, designing multiple-step-type p-type In0.67Ga0.33As0.7P0.3 contact layer and adjusting the thickness of the absorption layer, a design with good flat-top performance is demonstrated such that the quantum efficiency is 51.161% in the flat-top passband, 0.5 and 3dB bandwidths are 0.26 and 0.4nm, respectively. [Copyright &y& Elsevier]

Abstract: A new type of one-mirror inclined waveguide-grating photodetector, which combines a waveguide-grating filter and an inclined top mirror is proposed. Greatly improved spectral response is achieved by the integration of waveguide-grating into classical thin-film homogeneous layers. Comparison between the grating filter and Fabry–Perot filter demonstrates that this structure has two advantages over other photodetector devices. First, the inclined mirror can decouple the quantum efficiency from response speed and spectral response linewidth. Second, comparing the traditional photodetector with Fabry–Perot filter, this type of photodetector with the same materials requires significantly fewer layers while maintaining the same linewidth response, high peak efficiency and remarkably low sideband reflectivity. Thus, this type of photodetector device represents basic new optical features with a significant potential for practical applications. [Copyright &y& Elsevier]

The NiO thin film ohmic contact to the p-type In 0.53 Ga 0.47 As and non-doped In 0.53 Ga 0.48 As was experimentally demonstrated. The ohmic contact mechanism is mainly due to the small valence band offset between the NiO and InGaAs. The NiO thin film was synthesized through thermal oxidation. The oxidation time is the key factor affecting the contact properties of the NiO/InGaAs. It is promising for the application of NiO transparent electrodes in III-V compound material-based optical-electronic devices. [ABSTRACT FROM AUTHOR]

• We have proposed new formulas for analyzing and calculating the intrinsic dynamic resistance, gain, and cutoff frequency of double heterojunction bipolar transistors. • The reliability of our physics-based model through comparisons with experimental reports from three different research institutions. • Our work also introduces a novel method for obtaining the equivalent circuit of a transistor, providing an effective way to analyze various quantitative performance limiting factors. This can be extremely useful for designing and optimizing transistors. Significant discrepancies were found between experimental results and the results calculated by the conventional physics-based model for the cutoff frequency and some equivalent circuit parameters of double heterojunction bipolar transistors (DHBT). In order to accurately evaluate the primary quantitative performance of DHBT, a comprehensive physics-based model was developed and validated by comparing experimental data from three research institutions. The proposed physics-based model combines the equivalent circuit of the T-topology and hybrid-π topology, and includes modification formulas for estimating the intrinsic dynamic resistance of the base–collector and base-emitter junctions, as well as the cutoff frequency, the hybrid-π input capacitance, and the gain. [ABSTRACT FROM AUTHOR]

In this paper, we propose a monolithically integrated optical transceiving chip (IOTC) scheme by vertically integrating a resonant cavity enhance LED (RCLED) on its top side and a PIN-PD at its bottom side. It can be used for promoting the application of single fiber bi-direction (BiDi) transmission in plastic optical fiber (POF) link. For a fabricated IOTC, the transmitting function is realized by its RCLED unit, which emits light upwards to a POF at 804.6 nm with a FWHM of 4 nm. The receiving function is realized by its PIN-PD unit, which collects the light, while it passing through its RCLED unit, from the same POF. For realizing the transmitting and receiving function simultaneously, firstly, high optical isolation performance between the ITOC's two units should be realized, which means the RCLED's backlight should be as little as possible compared with its top emitting light. And the obtained optical isolation level between the fabricated IOTC's two units is higher than 30 dB. Secondly, high photo-response isolation performance between the ITOC's two units also need to be realized, which means the RCLED's photo-response to the receiving light should be as little as possible compared with the PIN-PD's photo-response. For the fabricated IOTC, it realizes a responsivity of 0.42A/W at the receiving wavelength around 831 nm and a photo-response isolation level of higher than 70 dB between its two units. For dynamic performance, the IOTC's RCLED unit obtains a 3 dB modulation bandwidth of 2.2 GHz, and its PIN-PD unit obtains a 3 dB photo-response bandwidth of 10.6 GHz. Within the 10.6 GHz bandwidth, the dynamic isolation level between the two units is higher than 30 dB. It should be feasible to be used for constructing in-home single POF BiDi optical link. [ABSTRACT FROM AUTHOR]

Cleft lip with or without cleft palate (CL/P) is one of the most common birth defects worldwide and is characterized by abnormalities of the orofacial structure. Syndromic CL/P is mainly caused by Mendelian disorders such as Van der Woude Syndrome (VWS). However, > 70% of CL/P cases are nonsyndromic, characterized by isolated orofacial cleft without any known syndrome. The etiology of nonsyndromic CL/P (NSCL/P) remains elusive, but it has been suggested that causative genes of syndromic CL/P might also contribute to NSCL/P. As such, the VWS causative gene IRF6 has been extensively studied in NSCL/P. Recently, GRHL3 was identified as another VWS causative gene. Thus, it may be a novel candidate gene for NSCL/P. In the present study, we genotyped 10 tag SNPs covering GRHL3 and performed association analysis with NSCL/P in 504 cases and 455 healthy controls. Our preliminary results identified rs10903078, rs4638975, and a haplotype rs10903078-rs6659209 of GRHL3 that exceeded the significance threshold (p < 0.05), though none survived Bonferroni correction for multiple comparisons. As the first study between GRHL3 and NSCL/P, the contribution of this gene to NSCL/P etiology should be interpreted with caution based on existing evidence. Further, the robustness of association between GRHL3 and NSCL/P should be further validated in expanded cohorts. [ABSTRACT FROM AUTHOR]

High-order quadrature amplitude modulation (QAM) is a promising approach for increasing the spectral efficiency of wavelength-division-multiplexing transmission, but its optical implementation is still challenging. We propose a customized IQ modulator for generating 64-QAM using equal-amplitude electrical binary drive signals and verify the operation through simulations. Using the embedded VOAs, the transmitter can be finely controlled and flexible for several modulation formats. [ABSTRACT FROM AUTHOR]

• Three asymmetric grating structures not only significantly improve the output power of lasers, but also improve the utilization efficiency of output power to reduce energy consumption. • Silicon evanescent lasers with designed waveguide structure exhibit large waveguide-coupled power and low threshold current density. • Calculation method combines the advantages of eigenmode expansion method and coupled-wave theory. Great achievements in the bonded III–V lasers have pushed the productization process of silicon photonic chips. In this work, we report the design of silicon evanescent lasers with asymmetric gratings, which can provide high output power and stable single-longitudinal-mode operation. The high coupling efficiency and low threshold current density are achieved by linearly expanding the width of rib waveguide from 0.4 µm to 2 µm through 150 µm taper coupler. By optimizing the λ/4 phase-shift position ratio from conventional 0.50 to 0.64, the ratio of output power at both sides of the bonded lasers (P 2 / P 1) is improved from1.0 to 5.0, and the normalized grating coupling coefficient (κ L) remains at 2.78. By optimizing the duty cycle at one side of λ/4 phase-shift from 0.5 to 0.8 and another side remains at 0.5, P 2 / P 1 is 3.3, and κ L lowers from 2.78 to 2.21. Besides, keeping the phase-shift position ratio at 0.64 while changing the duty cycle to 0.7, P 2 / P 1 increases significantly to 7.5 with κ L of 2.59. This work provides a step forward towards the development of high-power silicon-based light sources. [ABSTRACT FROM AUTHOR]

Abstract: Multiagent systems have been studied and widely used in the field of artificial intelligence and computer science to catalyze computation intelligence. In this paper, a multiagent evolutionary algorithm called RAER based on the ERA multiagent modeling pattern is proposed, where ERA has the same architecture as Swarm including three parts of Environment, Reactive rules and Agents. RAER integrates a novel roulette inversion operator (RIO) proposed in this paper and theoretically proved to conquer the irrationality of the inversion operator (IO) designed by John Holland when used for real code stochastic optimization algorithms. Experiments for numerical optimization of 4 benchmark functions show that the RIO operator bears better functioning than IO operator. And experiments for numerical optimization of 12 benchmark functions are used to examine the performance and scalability of RAER along the problem dimensions ranging 20–10000, results indicate that RAER outperforms other comparative algorithms significantly. Also, two engineering optimization problems of a stable linear system approximation and a welded beam design are used to examine the applicability of RAER. Results show that RAER has better search ability and faster convergence speed. Especially for the approximation problem, REAR can find the proper optima belonging to different fixed search areas, which is significantly better than other algorithms and shows that RAER can search the problem domains more thoroughly than other algorithms. Hence, RAER is efficient and practical. [Copyright &y& Elsevier]

The induced-birefringence effects on uniform fiber Bragg grating (FBG) and linearly chirped FBG under lateral compression are experimentally investigated, respectively. The group delay (GD) characteristics of linearly chirped FBG under lateral compression are given for the first time. The birefringence of the FBG can be accurately controlled through tuning the voltage applied on piezoelectric transducer (PZT). The experimental results show good agreement with numerical simulations. First-order polarization mode dispersion (PMD) can be compensated with linearly chirped fiber Bragg grating. [Copyright &y& Elsevier]

Photodiode equivalent circuit models often involve numerous parameters, making the parameter extraction process complex. Therefore, this work presents a hybrid genetic algorithm (HGA) to extract photodiode parameters. Firstly, we deduce the calculation formula of the scattering parameters of the photodiode equivalent circuit model. Then, to address the limitations of the standard genetic algorithm (SGA) that its slow convergence and extended search times, we incorporate the elite strategy and acceleration operator, enhancing the local search ability of HGA. We compare the performance of the HGA with the other four optimization algorithms under multiple sets of measured data. Results show that HGA has better performance in parameter fitting, convergence speed, and accuracy from 10 MHz to 40 GHz, highlighting its superiority. The algorithm significantly simplifies photodiode parameter extraction, and provides a feasible solution for the parameter extraction of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Abstract: We propose a novel waveguide based on a structure of coupled asymmetric subwavelength-diameter wires to realize a high negative dispersion. The waveguide consists of an optical nanofiber and a GaAs nanowire. The properties of the supermodes are calculated using finite elements method. The results show that the symmetric supermode in the coupled structure can exhibit a giant negative dispersion up to −4.5×106 ps/nm/km. [Copyright &y& Elsevier]

Abstract In this letter, we demonstrate the monolithic vertical integration of vertical-cavity surface-emitting laser (VCSEL) with resonant cavity enhancement photodetector (RCEPD) for the application to bidirectional optical interconnect. Based on the optimal designed structure, the monolithic integrated device can realize optical decoupling and electrical isolation between its VCSEL unit and RCEPD unit. The VCSEL unit exhibits a threshold current of 1.65 mA, a slope efficiency of 0.58 W/A and 3 dB bandwidth of 12.8 GHz. Regarding the RCEPD unit, the width of its absorption quantum efficiency spectrum is 8 nm with a quantum efficiency of higher than 50%. The 3 dB response bandwidth of the RCEPD unit can be up to 65.7 GHz. [ABSTRACT FROM AUTHOR]

Nickel sulfides and nickel selenides have been widely explored as electrodes for supercapacitors (SCs) due to their high theoretical capacitances and low cost. However, the poor electrical conductivity and sluggish ion transport hinder their widespread applications in SCs. Herein, a series of (Ni 3 S 2 /NiSe-3:1)/carboxymethylcellulose derived carbon, (Ni 3 S 2 /NiSe-3:1)/CMC-C, heterostructures are built by one-step vulcanization, selenization and carbonization using Ni(OH) 2 /CMC-C as the precursor. By tuning the mass ratio of sulfur to selenium, one unique hairbrush-like (Ni 3 S 2 /NiSe-3:1)/CMC-C heterostructure with uniform nanorod arrays is formed, which exposes substantial redox active sites. The optimal (Ni 3 S 2 /NiSe-3:1)/CMC-C electrode displays high specific capacitance of 2005.1 F g−1 (842.1 mAh g−1) at 7 A g−1 and 1075.1 F g−1 (451.5 mAh g−1) at 35 A g−1. Furthermore, asymmetric supercapacitors (ASCs) with the (Ni 3 S 2 /NiSe-3:1)/CMC-C as anode and activated carbon (AC) as cathode are assembled and evaluated. The ASCs exhibit an energy density of 41.9 Wh kg−1 at a power density of 709.8 W kg−1 and reasonable cycling stability (77.5% retention, 10,000 cycles), indicating that the (Ni 3 S 2 /NiSe-3:1)/CMC-C electrode has broad application prospects in SCs and related energy applications. A novel hairbrush-like (Ni 3 S 2 /NiSe-3:1)/CMC-C heterostructure with uniform nanorod arrays was constructed. The (Ni 3 S 2 /NiSe-3:1)/CMC-C electrode and (Ni 3 S 2 /NiSe-3:1)/CMC-C//AC ASCs exhibited excellent capacitive performances due to substantial exposed redox active sites and improved ion/charge transfer. [Display omitted] • A series of (Ni 3 S 2 /NiSe-x:y)/CMC-C heterostructures were constructed. • The hairbrush-like structure with nanorod arrays exposed abundant active sites. • The charge transfer and redox reaction kinetics were greatly accelerated. • The (Ni 3 S 2 /NiSe-3:1)/CMC-C exhibited excellent electrochemical performances. [ABSTRACT FROM AUTHOR]

To investigate the association between PTCH1 single nucleotide polymorphism(SNP) and non-syndromic cleft lip with or without palate (NSCL/P) in the Ningxia Hui Autonomous region and predict the function of single nucleotide polymorphism through bioinformatics analysis. A case-control analysis of 31 single nucleotide polymorphism locus alleles on PTCH1 gene (504 cases and 455 controls) was performed to explore the association between PTCH1 gene polymorphisms and non-syndromic cleft lip with or without palate in Ningxia region. Transcription factors, 3D single nucleotide polymorphism and other related information of single nucleotide polymorphism loci with statistical significance were screened by the case-control experiments, and then analyzed the corresponding transcription factors through the NCBI database. The case-control study showed that 5 of the 31 single nucleotide polymorphism loci rs357564 (P = 0.0233), rs1805155 (P = 0.0371), rs28446116 (P = 0.0408), rs2282041 (P = 0.0439), rs56119276 (P = 0.0256) had statistically significant differences in allele frequencies between the case and control groups. Bioinformatics analysis revealed that EP300 and RUNX3 , among the transcription factors associated with rs28446116, may be associated with the development of non-syndromic cleft lip with or without palate. PTCH1 gene may be associated with the occurrence of non-syndromic cleft lip with or without palate in the Ningxia region, which may be related to the role of EP300 and RUNX3 in the development of cleft lip and palate. • PTCH1 gene is associated with non-syndromic cleft lip with or without palate. • Transcription factors EP300 and RUNX3 interact with PTCH1 gene in 3D spatial structure. • 3D single nucleotide polymorphism analysis can predict gene interactions. [ABSTRACT FROM AUTHOR]

Abstract: In this study, BGaAsSb thick layers and BGaAsSb/GaAs quantum wells (QWs) have been grown on GaAs (001) by low pressure metal–organic vapor deposition (LP-MOCVD) for the first time. It has been found that for both GaAs1−y Sb y thick layer and GaAs1−y Sb y /GaAs QWs, the incorporation of boron leads to a decrease in Sb segregation and causes an increased solid Sb content y as well as a higher compressive strain. Similarly, Sb segregation also recedes when the arsenic partial pressure is lowered, and Sb-incorporation efficiency increases significantly. In both cases, the quaternary BGaAsSb alloys cannot be grown lattice-matched to GaAs. In addition, the PL peak wavelength red-shifts when boron is incorporated. This is in accordance with the increased Sb content. [Copyright &y& Elsevier]

Abstract: We propose a novel asymmetric dual-core hybrid photonic crystal fiber (PCF) coupler composed of a silicon tube as the left core and a silica core as the right core. The control of picosecond pulse delay is achievable by means of power adjusting. The transmission modes, dispersion characteristics and coupling coefficients of the proposed coupler are investigated numerically. The results demonstrate that it is possible to obtain 2.0ps time delay for soliton pulse with 2.0ps temporal width within 1cm length. Further numerical results show that the coupler can generate 10.0ps undistorted time advance within 5cm length. [Copyright &y& Elsevier]

Abstract: InAs/GaAs dots-on-nanowire (NW) hybrid heterostructures are grown on Si substrate by metal organic chemical vapor deposition. The formation of InAs quantum dots (QDs) is intimately associated with the NW density as well as the substrate surface properties, both of which strongly affect the surface adatom diffusion. InAs QDs are realized with a short deposition time by reducing the NW density. The QDs exhibit specific facets and pure zinc blende structure, residing on a wetting layer of several nanometers. Photoluminescence emission from the QDs is observed at room temperature, with a linewidth of 186meV. The results are promising for future integration of III–V NW hybrid devices, especially photovoltaic cells on Si. [Copyright &y& Elsevier]