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11.
Mahdi Rabbani Yongli Wang Reza Khoshkangini Hamed Jelodar Ruxin Zhao Sajjad Bagheri Baba Ahmadi Seyedvalyallah Ayobi 《Entropy (Basel, Switzerland)》2021,23(5)
Network anomaly detection systems (NADSs) play a significant role in every network defense system as they detect and prevent malicious activities. Therefore, this paper offers an exhaustive overview of different aspects of anomaly-based network intrusion detection systems (NIDSs). Additionally, contemporary malicious activities in network systems and the important properties of intrusion detection systems are discussed as well. The present survey explains important phases of NADSs, such as pre-processing, feature extraction and malicious behavior detection and recognition. In addition, with regard to the detection and recognition phase, recent machine learning approaches including supervised, unsupervised, new deep and ensemble learning techniques have been comprehensively discussed; moreover, some details about currently available benchmark datasets for training and evaluating machine learning techniques are provided by the researchers. In the end, potential challenges together with some future directions for machine learning-based NADSs are specified. 相似文献
12.
Ismail A. Haj Waseem Hafiz Muhammad Ishtiaq Muhammad Jamal Sajjad Shaukat Khan Majid 《International Journal of Theoretical Physics》2021,60(5):1720-1741
International Journal of Theoretical Physics - Most of the enciphering structures are based on the transformation of mediums by describing the strict criteria. The presented article is based on... 相似文献
13.
Sajjad S Leghari SA Chen F Zhang J 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(46):13795-13804
A controllable and reproducible synthesis of highly ordered two-dimensional hexagonal mesoporous, crystalline bismuth-doped TiO(2) nanocomposites with variable Bi ratios is reported here. Analyses by transmission electron microscopy, X-ray diffraction, Raman, and X-ray photoelectron spectroscopy reveal that the well-ordered mesostructure is doped with Bi, which exists as Bi(3+) and Bi((3+x+)). The Bi-doped mesoporous TiO(2) (ms-TiO(2)) samples exhibit improved photocatalytic activities for simultaneous phenol oxidation and chromium reduction in aqueous suspension under visible and UV light over the pure ms-TiO(2), P-25, and conventional Bi-doped titania. The high catalytic activity is due to both the unique structural characteristics and the Bi doping. This new material extends the spectral response from UV to the visible region, and reduces electron-hole recombination, which renders the 2.0% Bi-doped ms-TiO(2) photocatalyst highly responsive to visible light. 相似文献
14.
Ahmad Shaabani Ali Hossein Rezayan Afshin Sarvary Sajjad Keshipour Hamid Reza Khavasi 《Tetrahedron letters》2010,51(31):4091-3424
An unexpected coupling reaction between isocyanides and carboxylic acids which led to the synthesis of highly stable symmetrical and unsymmetrical alkylamidine and arylamidine carbocations under mild reaction conditions is described. The structures of these compounds were confirmed by IR, mass, 1H NMR, 13C NMR, and single-crystal X-ray diffraction studies and a plausible mechanism is proposed. 相似文献
15.
Zeid Abdullah Alothman Nausheen Bukhari Sajjad Haider Saikh Mohammad Wabaidur Abdulrahman A. Alwarthan 《Arabian Journal of Chemistry》2010,3(4):251-255
A novel sensitive fluorimetric method was investigated for the assay of fexofenadine hydrochloride (FEX) using silver nanoparticles (NPs) as a fluorescence probe. The NPs, which were prepared by chemical reduction of silver nitrate with sodium borohydride (reducing agent) in aqueous solution (without organic stabilizers) were water soluble, stable and had narrow emission band. The addition of drug to NPs solution caused considerable quenching of the emission band of silver NPs, which was likely due to the complexation of the drug to silver NPs. Under the optimum conditions, the quenched fluorescence (FL) intensity was linear with the concentration of FEX in the range of 1 × 10?7 to 2.5 × 10?5 mol L?1 (0.9985) with a detection limit of 1.2 × 10?8 mol L?1. The quenching mechanism of the studied drug on the emission band of silver NPs was explained by Stern–Volmer law. The developed method was applied to FEX determination in a pharmaceutical formulation (allegra tablets) and biological fluids (human serum and urine). 相似文献
16.
Crochet JJ Hoseinkhani S Lüer L Hertel T Doorn SK Lanzani G 《Physical review letters》2011,107(25):257402
We present evidence for the generation of free carriers in aggregated single-wall carbon nanotubes by photoexcitation in the energetic range of the π→π(*) transition associated with the M saddle point of the graphene lattice. The underlying broad absorption culminating at 4.3 eV can be fit well with a Fano line shape that describes strong coupling of a saddle-point exciton to an underlying free electron-hole pair continuum. Moreover, it is demonstrated that transitions in this energetic region autoionize into the continuum by detecting features unique to the presence of free charges in the transient transmission spectra of the continuum-embedded second sub-band exciton, S(2). 相似文献
17.
Humayun Ajaz Sajjad Hussain Muhammad Altaf Helen Stoeckli‐Evans Anvarhusein A. Isab Rashid Mahmood Shahnila Altaf Saeed Ahmad 《中国化学》2011,29(2):254-258
Antimony(III) complexes of thioamides [thioamides=thiourea (Tu), N,N′‐dimethylthiourea (Dmtu), tetramethylthiourea (Tmtu), imidazolidine‐2‐thione (Imt) and diazinane‐2‐thione (Diaz)] with the general formulae, Sb(thione)nCl3 (n=1, 2, 2.5, 3) were prepared and characterized by elemental analysis, IR and NMR (1H, 13C) spectroscopic methods. The spectral data of the complexes are consistent with the coordination of the thiones to antimony(III). The crystal structure of one of them, {[Sb(Imt)2Cl2]2(μ2‐Imt)}Cl2 ( 1 ), was determined by X‐ray crystallography, which shows that the complex is dinuclear consisting of two [Sb(Imt)2Cl2] units bridged by an Imt molecule. In 1 , the antimony atom is bonded to two chlorine atoms, two sulfur atoms of coordinated Imt molecules and one sulfur atom of a bridging Imt molecule. The antimony environment can be considered to be distorted octahedral with one Cl? ion weakly bound to antimony. 相似文献
18.
19.
ABSTRACTIn this paper, lanthanum was used as a chemical modifier for the direct determination of erbium by high-resolution continuum source electrothermal atomic absorption spectrometry. A two-step experimental design was used for optimization, first a full factorial design was conducted for identification of significant factors, and then a central composite design was carried out for final optimization of the significant factors. The optimum parameters were obtained as follows: atomization temperature of 2500°C, pyrolysis temperature of 1600°C, and pyrolysis time of 10?s in the presence of lanthanum as a chemical modifier. Under optimum conditions, the characteristic mass, limit of detection, and limit of quantification were 29?pg, 0.71, and 2.4?µg?L?1, respectively. The precision of the method, estimated as the relative standard deviation for 10 replicate measurements of 50?µg?L?1 of erbium, was 1.8%. The optimized method was applied to determine erbium content in sediments and rock samples. The determined values of erbium in sediment certified reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. 相似文献
20.
Sajjad Uzair Hussain Imtiyaz Hamid Khalid Bhat Showkat Ahmad Ali Hafiz Muhammad Wang Chi-Chuan 《Journal of Thermal Analysis and Calorimetry》2021,145(4):1911-1923
Journal of Thermal Analysis and Calorimetry - Owing to the high nucleation site density and relatively robust behavior, sintered coated surfaces are of great interest for thermal management via... 相似文献