A Hypergraph-Based Machine Learning Ensemble Network Intrusion Detection System

Network intrusion detection systems (NIDS) to detect malicious attacks continues to meet challenges. NIDS are vulnerable to auto-generated port scan infiltration attempts and NIDS are often developed offline, resulting in a time lag to prevent the spread of infiltration to other parts of a network. To address these challenges, we use hypergraphs to capture evolving patterns of port scan attacks via the set of internet protocol addresses and destination ports, thereby deriving a set of hypergraph-based metrics to train a robust and resilient ensemble machine learning (ML) NIDS that effectively monitors and detects port scanning activities and adversarial intrusions while evolving intelligently in real-time. Through the combination of (1) intrusion examples, (2) NIDS update rules, (3) attack threshold choices to trigger NIDS retraining requests, and (4) production environment with no prior knowledge of the nature of network traffic 40 scenarios were auto-generated to evaluate the ML ensemble NIDS comprising three tree-based models. Results show that under the model settings of an Update-ALL-NIDS rule (namely, retrain and update all the three models upon the same NIDS retraining request) the proposed ML ensemble NIDS produced the best results with nearly 100% detection performance throughout the simulation, exhibiting robustness in the complex dynamics of the simulated cyber-security scenario.Comment: 12 pages, 10 figure

Bis(2-amino­pyrimidine-κN 1)dibromidozinc(II)

The title compound, [ZnBr2(C4H5N3)2], is a mononuclear complex in which the ZnII ions have distorted tetra­hedral coordination geometry. The ZnII ion binds to two N atoms from two different 2-amino­pyrimidine ligands and two bromide ions. N—H⋯N hydrogen bonds link the mol­ecules to form a one-dimensional supra­molecular structure. The supra­molecular chains are parallel to each other and N—H⋯Br hydrogen bonds link them into a two-dimensional network in the ac plane. Additionally, there are strong π–π inter­actions [centroid–centroid distance = 3.403 (3) Å]

4-[6,8-Dibromo-2-(2-chloro-5-nitro­phen­yl)-1,2,3,4-tetra­hydro­quinazolin-3-yl]cyclo­hexa­nol

The title compound, C20H20Br2ClN3O3, was synthesized by the condensation reaction of 2-chloro-5-nitro­benzaldehyde with 4-(2-amino-3,5-dibromo­benzyl­amino)cyclo­hexa­nol in a methanol solution. There are two independent mol­ecules in the asymmetric unit and in one mol­ecule the atoms of the cyclo­hexane ring are disordered over two sets of sites with refined occupancies of 0.657 (12) and 0.343 (12). The dihedral angle between the two benzene rings is 89.5 (2)° in one mol­ecule and 82.9 (2)° in the other. In the crystal structure, inter­molecular N—H⋯O and O—H⋯O hydrogen bonds link the mol­ecules into chains propagating along [01]

Maximizing lifetime of range-adjustable wireless sensor networks: a neighborhood-based estimation of distribution algorithm

Sensor activity scheduling is critical for prolonging the lifetime of wireless sensor networks (WSNs). However, most existing methods assume sensors to have one fixed sensing range. Prevalence of sensors with adjustable sensing ranges posts two new challenges to the topic: 1) expanded search space, due to the rise in the number of possible activation modes and 2) more complex energy allocation, as the sensors differ in the energy consumption rate when using different sensing ranges. These two challenges make it hard to directly solve the lifetime maximization problem of WSNs with range-adjustable sensors (LM-RASs). This article proposes a neighborhood-based estimation of distribution algorithm (NEDA) to address it in a recursive manner. In NEDA, each individual represents a coverage scheme in which the sensors are selectively activated to monitor all the targets. A linear programming (LP) model is built to assign activation time to the schemes in the population so that their sum, the network lifetime, can be maximized conditioned on the current population. Using the activation time derived from LP as individual fitness, the NEDA is driven to seek coverage schemes promising for prolonging the network lifetime. The network lifetime is thus optimized by repeating the steps of the coverage scheme evolution and LP model solving. To encourage the search for diverse coverage schemes, a neighborhood sampling strategy is introduced. Besides, a heuristic repair strategy is designed to fine-tune the existing schemes for further improving the search efficiency. Experimental results on WSNs of different scales show that NEDA outperforms state-of-the-art approaches. It is also expected that NEDA can serve as a potential framework for solving other flexible LP problems that share the same structure with LM-RAS

Passive Removal of Silicone Oil with Temporal Head Position through Two 23-Gauge Cannulas

Purpose. To report a new approach for removal of silicone oil. Methods. All surgeries were performed using 23-gauge vitrectomy system with two transconjunctival sutureless cannulas. At the beginning, most of the silicone oil was removed by traditional microinvasive vitrectomy system through inferior-temporal cannula. Then, the blood transfusion tube is removed from the inferior-temporal cannula, and the fluid-air exchange is performed. A passive fluid-air exchange was performed to aspirate the residual silicone oil after gradually turning the patient’s head temporally by approximately 90° gradually. Results. After the surgery, all patients had a clear anterior chamber and vitreous cavity on slit lamp and B scan examination, respectively. The mean time taken for silicone oil removal and total surgery was 8.0±1.4 minutes and 12.4±2.5 minutes, respectively. The mean intraocular pressure 1 day, 3 days, 1 week, 1 month, and 3 months after surgery was 9.0±5.8 mmHg, 11.3±7.6 mmHg, 16.1±6.9 mmHg, 17.7±4.8 mmHg, and 17.1±3.5 mmHg, respectively. Conclusion. This new approach may provide a safe and fast method to remove the silicone oil

Storage of multiple single-photon pulses emitted from a quantum dot in a solid-state quantum memory

Quantum repeaters are critical components for distributing entanglement over long distances in presence of unavoidable optical losses during transmission. Stimulated by Duan-Lukin-Cirac-Zoller protocol, many improved quantum-repeater protocols based on quantum memories have been proposed, which commonly focus on the entanglement-distribution rate. Among these protocols, the elimination of multi-photons (multi-photon-pairs) and the use of multimode quantum memory are demonstrated to have the ability to greatly improve the entanglement-distribution rate. Here, we demonstrate the storage of deterministic single photons emitted from a quantum dot in a polarization-maintaining solid-state quantum memory; in addition, multi-temporal-mode memory with $1$, $20$ and $100$ narrow single-photon pulses is also demonstrated. Multi-photons are eliminated, and only one photon at most is contained in each pulse. Moreover, the solid-state properties of both sub-systems make this configuration more stable and easier to be scalable. Our work will be helpful in the construction of efficient quantum repeaters based on all-solid-state devicesComment: Published version, including supplementary materia

Plasmonic photoluminescence for recovering native chemical information from surface-enhanced Raman scattering

表面增强拉曼光谱(SERS)可以提供高达单分子的检测灵敏度和特异的分子指纹信息，是一个非常有前景的分析技术。SERS增强主要源自贵金属纳米结构的局域表面等离激元共振(LSPR)效应。虽然SERS研究者早已意识到该效应强烈依赖于激光波长，并对不同频率的拉曼谱峰增强效果不同，但是迄今为止仍缺乏有效的方法对SERS谱峰相对强度进行可靠的矫正，也常有文献错误解读SERS强度信息，从而过度或错误地解释实验结果。 在该工作中，任斌教授课题组采用单粒子光谱技术从实验上直接检测SERS光谱和金属纳米粒子的光致发光谱(PL)，通过定量研究两者的关联，提出了一种普适的方法矫正LSPR对不同拉曼谱峰相对强度的影响，为理解表面物种构型和作用方式提供了本征的化学指纹信息。【Abstract】Surface-enhanced Raman scattering (SERS) spectroscopy has attracted tremendous interests as a highly sensitive label-free tool. The local field produced by the excitation of localized surface plasmon resonances (LSPRs) dominates the overall enhancement of SERS. Such an electromagnetic enhancement is unfortunately accompanied by a strong modification in the relative intensity of the original Raman spectra, which highly distorts spectral features providing chemical information. Here we propose a robust method to retrieve the fingerprint of intrinsic chemical information from the SERS spectra. The method is established based on the finding that the SERS background originates from the LSPR-modulated photoluminescence, which contains the local field information shared also by SERS. We validate this concept of retrieval of intrinsic fingerprint information in well controlled single metallic nanoantennas of varying aspect ratios. We further demonstrate its unambiguity and generality in more complicated systems of tip-enhanced Raman spectroscopy (TERS) and SERS of silver nanoaggregates.该工作得到国家自然科学基金委（项目批准号：21633005、21621091和J1310024）、科技部（项目批准号：2013CB933703、2016YFA0200601）、教育部等部门的大力资助与支持

Elimination of ascorbic acid and sensitive detection of uric acid at the MnO2 nanorods/graphene-based modified electrode

The α-MnO2 nanorods (MnO2 NR) were first synthesized and then incorporated onto the basal plane of reduced graphene oxide (RGO) with the aid of ultrasonication to obtain a composite (MnO2 NR/RGO). A novel modified electrode (MnO2 NR/RGO/GCE) based on the MnO2 NR/RGO composite was fabricated and used for the selective detection of uric acid (UA) in the mass of ascorbic acid (AA). The as-made modified electrode shows a good electron transfer ability and displays a novel performance for the detection of UA. More interestingly, this electrode can effectively eliminate the interference of AA. A linear dependence on the concentration of UA from 5 × 10-8 to 4 × 10-4 M was measured by differential pulse voltammetry (DPV), and the detection limit was up to 1 × 10-8 M. The good sensitivity and repeatability of the proposed electrode enabled its successful application for the selective determination of UA in human urine sample analysis. These results will enhance our understanding of the applicability of MnO2 NR/RGO in electrochemical analysis

Observing atomic layer electrodeposition on single nanocrystals surface by dark field spectroscopy

从单颗粒水平研究电化学表面和界面过程，特别是欠电位沉积是电化学领域的一个重要挑战。欠电位沉积通常仅涉及单原子层到亚单原子层的物种，但是能够显著调控金属表面电子结构，是制备高效电催化剂的一个重要的方法。然而目前在电化学环境下表征单个粒子表面单层原子的变化仍然是个巨大的挑战，针对上述挑战，任斌教授课题组发展了一套高灵敏的电化学暗场散射光谱装置，在不使用特殊光源的情况下，可以使得检测的粒径小至10-15 nm，灵敏度提高到亚单层原子。该工作是在任斌教授指导下，主要由化学化工学院已毕业博士生胡树（第一作者）完成。李剑锋教授及其课题组的博士生张月皎在单晶电化学实验上提供了重要帮助。已毕业博士生易骏在理论计算方面提供了有力支持。Underpotential deposition offers a predominant way to tailor the electronic structure of the catalytic surface at the atomic level, which is key to engineering materials with a high activity for (electro)catalysis. However, it remains challenging to precisely control and directly probe the underpotential deposition of a (sub)monolayer of atoms on nanoparticle surfaces. In this work, we in situ observe silver electrodeposited on gold nanocrystals surface from submonolayer to one monolayer by designing a highly sensitive electrochemical dark field scattering setup. The spectral variation is used to reconstruct the optical “cyclic voltammogram” of every single nanocrystal for understanding the underpotential deposition process on nanocrystals, which cannot be achieved by any other methods but are essential for creating novel nanomaterials.The authors thank Dr. Hai-Xin Lin for helpful discussion of nanoparticle synthesis and characterization. The authors acknowledge support from the Natural Science Foundation of China (21633005, 21790354, and 21711530704) and the Ministry of Science and Technology of China (2016YFA0200601).该研究工作得到了国家自然科学基金委和科技部等的资助和支持