基于溯源图和注意力机制的APT攻击检测模型构建

针对现有攻击检测方法难以应对持续时间长、攻击手段复杂隐蔽的高级持续威胁的问题,构建了基于注意力机制和溯源图的APT攻击检测模型。首先,基于系统的审计日志构建能够描述系统行为的溯源图;其次,设计优化算法,确保在不牺牲关键语义的前提下缩减溯源图规模;再次,利用深度神经网络(DNN)将原始攻击序列转换为语义增强的特征向量序列;最后,设计并实现了APT攻击检测模型DAGCN,该模型将注意力机制应用于溯源图序列,利用该机制对输入序列的不同位置分配不同的权重并进行权值计算,能够提取较长时间内的持续攻击的序列特征信息,从而有效地识别恶意节点,还原攻击过程。该模型在识别精确率等多个指标上均优于现有模型,在公开的APT攻击数据集上的实验结果表明,该模型在APT攻击检测中的精确率达到93.18%,优于现有主流检测模型。

Ce(NO_(3))_(3)和CeO_(2)纳米粒子对APTES膜耐腐蚀性的影响

目的通过对铜箔进行硅烷化处理,增强铜箔的耐腐蚀性能。方法采用化学浸泡法在9μm电解铜箔表面制备γ-氨丙基三乙氧基硅烷偶联剂(APTES)硅烷膜层、Ce^(3+)/APTES膜层、CeO_(2)/APTES膜层和Ce^(3+)/CeO_(2)/APTES膜层,对改性硅烷膜试样与空白试样进行接触角对照实验,对硅烷表面润湿性进行表征。在3.5%(质量分数)NaCl溶液中,对空白样、单一硅烷膜层、Ce^(3+)/APTES硅烷膜层和Ce^(3+)/CeO_(2)/APTES硅烷膜层进行浸泡实验和电化学实验,研究改性膜层前后的耐腐蚀性能。通过扫描电子显微镜(SEM)观察膜层表面形貌,并利用傅里叶变换红外光谱(FTIR)和X射线光电子能谱(XPS)对纳米粒子结构进行分析,探讨改性膜层的钝化机理。结果Ce(NO_(3))_(3)/CeO_(2)/APTES复合膜层的接触角最大,接触角为106.6°,表现出最佳的疏水性。同时,其表面的腐蚀坑数量和面积最小。在盐水浸泡和电化学实验中,各试样的腐蚀电流密度随着浸泡时间的延长而上升,Ce^(3+)/CeO_(2)/APTES试样的腐蚀电位发生正移,具有较低的腐蚀电流密度,并且该试样具有最高的相角和最高的阻抗值,远高于Ce^(3+)/APTES试样。结论与单一硅烷膜层和仅分别添加Ce(NO_(3))_(3)、CeO_(2)2种缓蚀剂的膜层相比,Ce(NO_(3))_(3)/CeO_(2)/APTES复合膜层的防护效果有明显提升,且Ce^(3+)与CeO_(2)之间的协同作用大大提高了硅烷膜层的耐腐蚀性能。

Re-scaling and adaptive stochastic resonance as a tool for weak GNSS signal acquisition

Weak global navigation satellite system（GNSS） signal acquisition has been a limitation for high sensitivity GPS receivers. This paper modifies the traditional acquisition algorithms and proposes a new weak GNSS signal acquisition method using re-scaling and adaptive stochastic resonance（SR）. The adoption of classical SR is limited to low-frequency and periodic signals. Given that GNSS signal frequency is high and that the periodic feature of the GNSS signal is affected by the Doppler frequency shift, classical SR methods cannot be directly used to acquire GNSS signals. Therefore, the re-scaling technique is used in our study to expand its usage to high-frequency signals and adaptive control technique is used to gradually determine the Doppler shift effect in GNSS signal buried in strong noises. The effectiveness of our proposed method was verified by the simulations on GPS L1 signals. The simulation results indicate that the new algorithm based on SR can reach-181 d BW sensitivity with a very short data length of 1 ms.

工业互联网中抗APT窃取身份的零信任动态认证

新一代信息技术与工业系统深度融合,提升了工业控制系统和工业设备网络的连接性,使得工业互联网成为APT攻击的重点目标.针对现有偏向于静态认证的方法难以识别APT攻击者控制内部失陷终端获取的“傀儡身份”,进而造成敏感数据泄露的问题,提出一种面向工业互联网的零信任动态认证方案.融合CNN-BiLSTM构建混合神经网络,利用其时序特性设计行为因子预测模型.通过多个残差块组成的深度卷积网络提取特征,双向长短时记忆网络(bidirectional long short-term memory,BiLSTM)进行时间序列分析,生成对主体的行为因子预测,作为零信任动态认证重要凭据.为快速识别“傀儡身份”,融入行为因子设计IPK-SPA动态认证机制.利用轻量级标识公钥技术适应工业互联网海量末梢,借助零信任单包授权技术隐藏工控网络边界.安全性分析和实验结果表明,提出的动态认证方案具有较好的“傀儡身份”识别能力,有助于抗击工业互联网环境下因APT攻击者窃取身份导致的数据窃密威胁.

基于威胁发现的APT攻击防御体系研究

APT攻击的未知性和不确定性使得传统防护体系难以快速检测防御,其持续进化能力也使得基于特征检测技术的传统防护手段无法满足日益增长的安全需求。文章基于红蓝对抗思想构建了APT攻防模型,并基于杀伤链分类总结出常见网络攻击的步骤和技术。文章结合APT攻防实践经验提出一种以APT威胁发现为核心的防御思想模型和“云、管、端、地”协同的综合安全技术框架。

APT攻击下的无线通信网络最优主动防御决策模型

最优主动防御决策可以保障无线通信网络的安全稳定性,为了提高无线通信网络的防御效果,提出了APT攻击下的无线通信网络最优主动防御决策模型。关联无线通信网络日志,构建APT攻击对象集合,通过反馈相容系数计算APT攻击事件的绝对相容度,并预测APT攻击行为。基于APT攻击源对无线通信网络攻击的信道带宽,获取无线通信网络受到APT攻击的位置,利用无线通信网络节点的权值系数,提取无线通信网络的APT攻击特征。利用攻防图,计算得到APT攻击对无线通信网络的损害程度,通过定义无线通信网络的安全状态,构建了无线通信网络最优主动防御决策模型。实验结果表明,所提模型在防御无线通信网络的APT攻击时,可以将攻击数据包拒包率和吞吐量分别提高到90%以上和16000 bit/s以上,并且时延较低,具有更好的防御效果。

Digital signal acquisition system for complex nuclear reaction experiments

A digital data-acquisition system based on XIA LLC products was used in a complex nuclear reaction experiment using radioactive ion beams.A flexible trigger system based on a field-programmable gate array(FPGA)parametrization was developed to adapt to different experimental sizes.A user-friendly interface was implemented,which allows converting script language expressions into FPGA internal control parameters.The proposed digital system can be combined with a conventional analog data acquisition system to provide more flexibility.The performance of the combined system was veri-fied using experimental data.

Research on full-period acquisition method for diesel engine based on self-adaptive correlation analysis

Full-period signal acquisition of vibration signal plays a vital role in the health monitoring and fault diagnosis of modern industrial equipment group. The traditional full-period signal acquisition methods usually need not only a reference signal generated from special key phase device but also a reserved position, which is only suitable for a small number of particular equipment. A novel full-period signal acquisition method without key phase is proposed to construct the time-frequency method with strong energy concentration called the synchrosqueezing generalized S-Transform(SGST), combining together the Teager energy operator(TEO) and self-adaptive correlation analysis(SACA) based on the vibration signals of both gear and cylinder head. Actual vibration signals of diesel engine are employed to verify the feasibility and effectiveness of the proposed method by comparing with traditional method with special key phase device. By comparisons, the results show that full-period signal acquisition method without key phase has approximate accuracy for diesel engine under different working conditions.

基于APT活动全生命周期的攻击与检测综述

从攻击方法和检测方法两方面展开,首先综述高级持续威胁(APT)攻击的定义与特点,总结相关攻击模型的研究发展,在此基础上给出更一般性的APT全生命周期模型,并划分4个阶段,信息收集阶段、入侵实施阶段、内网攻击阶段和数据渗出阶段,对每一个阶段,重点调研近5年的研究论文,归纳总结各阶段的攻击与检测技术,并给出分析。最后,结合APT攻防技术相互博弈、快速发展的趋势,指出了当前攻防双方面临的挑战和未来研究的发展方向。

基于Apt@Au传感器的微囊藻毒素-LR传感检测

微囊藻毒素(MC-LR)是国际公共卫生组织已确认的一种神经毒素和致癌物质,其高效检测备受关注。该文通过金硫键作用将适配体直接结合到丝网印刷金电极表面,形成适配体@金(Apt@Au)敏感膜,当样本中存在MC-LR时,敏感膜上的适配体与MC-LR相互作用,引起[Fe(CN)_(6)]^(3-)/[Fe(CN)_(6)]^(4-)探针电对的电子传导发生变化,差分脉冲伏安(DPV)响应电流增加,由此构建了一种用于MC-LR检测的Apt@Au传感器。在优化的实验条件下,采用该传感器检测MC-LR的线性范围为0.001~50.00μg/L,检出限可达0.001μg/L,对微囊藻毒素-LA、微囊藻毒素-YR、节球藻毒素以及水体中常见的金属离子无明显响应,表现出良好的选择性。将其用于合成水样检测也显示出良好的回收率。Apt@Au传感器用于MC-LR检测具有流程简单、检测灵敏度高等优势,拥有良好的应用前景。

DPL联合APT570nm强脉冲光治疗黄褐斑的临床研究

研讨DPL与APT570nm两种不同波长的强脉冲光联合治疗黄褐斑的临床效果。方法 按随机数字表法收集2020年5月至2023年5月于我院皮肤科门诊医师诊断且符合研究入选标准的黄褐斑患者对照和治疗各30例。对照组:单用APT570nm强脉冲光治疗,治疗组:DPL联合APT570nm强脉冲光治疗;两组治疗间隔均为30天,共治疗5次,观察临床疗效。结果 治疗组疗效明显优于对照组,具有显著性差异[76.67%(23/30)比50.00%(15/30),X2=4.593,P<0.05];治疗前治疗组与对照组MASI 评分无统计意义[(11.59±5.34)分比(11.29±4.27)分,T=0.237,P>0.05],而治疗后两组MASI 评分有显著性差异[(3.33±2.69)分比(7.06±5.91)分,T=3.144,P<0.05]。治疗过程中两组均未出现明显潮红肿胀、水疱等不良情况。结论 DPL与APT 570nm两种不同波长的强脉冲光联合治疗黄褐斑能够明显改善色斑严重程度,显著增加疗效,值得应用。

基于APT特征的铁路网络安全性能研究

为了探究新网络安全形势下APT攻击对铁路网络安全造成的影响,文章首先分析APT攻击特点,提出融合APT过程的杀伤链模型,并据此总结APT攻击特点及对铁路网络安全可能产生的影响;然后分析铁路网络架构,对铁路外部服务网架构进行研究;最后根据提出的铁路网络模型图进行APT攻击建模,详细分析连接过程和连接指数,通过连接指数反映网络性能,进而展示网络攻击对网络安全性能的影响。仿真实验结果表明,APT攻击的发起对网络性能造成了显著不利影响,APT攻击产生后,非法用户的网络连接指数平均提升5倍以上。对比实验表明,APT攻击产生后,非法用户的连接指数比普通网络攻击平均提升2倍以上,这表明APT攻击的影响更加严重。

APT视域下高校英语云教学模式研究

随着互联网技术的迅猛发展,高校教学改革正逐步向智慧教学转型。新时代背景下,英语教学借助先进的技术和教育理念,在APT视域下,通过对评价手段、教学方法、技术工具的合理整合,构建云教学模式,并通过案例实践教学和教学效果分析,说明APT视域下的英语云教学模式能够提升学生学习的积极性,对提高学生的学习效果、推动教学模式创新、提高教学质量具有实践意义。

铁路APT攻击检测和溯源技术方案研究

针对传统防御技术的局限性,结合铁路系统特点,采用事前、事中、事后于一体安全防御策略,并将事前、事中、事后有机整合,按照铁路网分层架构,进行分布式、层级化纵深防御设计,提出“分布监测-智能识别-跨网溯源”为一体的铁路APT网络威胁感知与溯源技术方案,并在实验室搭建环境进行验证,可有效提升铁路系统针对APT攻击的防范能力。

Quantifying the Effects of Near-Surface Viscosity on Seismic Acquisition Geometry: A case study from Chepaizi Exploration Area, Junggar Basin (NW China)

The Chepaizi Exploration Area,Junggar Basin(NW China)holds substantial importance for seismic exploration endeavors,yet it poses notable challenges due to the intricate nature of its subsurface and near-surface conditions.To address these challenges,we introduce a novel and comprehensive workflow tailored to evaluate and optimize seismic acquisition geometries while considering the impacts of near-surface viscosity.By integrating geological knowledge,historical seismic data,and subsurface modeling,we conduct simulations employing the visco-acoustic wave equation and reverse-time migration to produce detailed subsurface images.The quality of these images is quantitatively evaluated using a local similarity metric,a pivotal tool for evaluating the accuracy of seismic imaging.The culmination of this workflow results in an automated optimization strategy for acquisition geometries that enhances subsurface exploration.Our proposed methodology underscores the importance of incorporating near-surface viscosity effects in seismic imaging,offering a robust framework for improving the accuracy of subsurface imaging.Herein,we aim to contribute to the advancement of seismic imaging methodologies by providing valuable insights for achieving high-quality seismic exploration outcomes in regions characterized by complex subsurface and near-surface conditions.

A Synchronization Acquisition Algorithm Based on the Frequency Hopping Pulses Combining

As modern electromagnetic environments are more and more complex,the anti-interference performance of the synchronization acquisition is becoming vital in wireless communications.With the rapid development of the digital signal processing technologies,some synchronization acquisition algorithms for hybrid direct-sequence(DS)/frequency hopping(FH)spread spectrum communications have been proposed.However,these algorithms do not focus on the analysis and the design of the synchronization acquisition under typical interferences.In this paper,a synchronization acquisition algorithm based on the frequency hopping pulses combining(FHPC)is proposed.Specifically,the proposed algorithm is composed of two modules:an adaptive interference suppression(IS)module and an adaptive combining decision module.The adaptive IS module mitigates the effect of the interfered samples in the time-domain or the frequencydomain,and the adaptive combining decision module can utilize each frequency hopping pulse to construct an anti-interference decision metric and generate an adaptive acquisition decision threshold to complete the acquisition.Theory and simulation demonstrate that the proposed algorithm significantly enhances the antiinterference and anti-noise performances of the synchronization acquisition for hybrid DS/FH communications.

智慧课堂与APT教学模型融合下的大学英语课堂教学策略构建

在当今信息化时代,教育技术正日益成为推动教育改革的重要力量。智慧课堂作为一种新型的教育形态,以其独特的互动性、个性化学习支持和智能化教学管理,为大学英语教学提供了新的发展机遇。然而,如何将智慧课堂与有效的教学模型相结合,以提高大学英语教学质量,成为当前教育领域关注的焦点。APT(Assessment, Pedagogy, Technology)教学模型作为一种集评估、教学法和技术于一体的教学框架,为大学英语课堂教学策略的构建提供了理论指导。因此,本研究旨在探讨智慧课堂与APT教学模型融合下的大学英语课堂教学策略构建,以期为我国大学英语教学的改革和发展提供实践路径和理论支持。

Nonsteroidal anti-inflammatory drugs before endoscopic ultrasound guided tissue acquisition to reduce the incidence of post procedural pancreatitis

Endoscopic ultrasound(EUS)with fine needle aspiration or fine needle biopsy is the gold standard for sampling tissue to diagnose pancreatic cancer and auto-immune pancreatitis or to analyze cyst fluid.The most common reported adverse event of fine needle aspiration and/or fine needle biopsy is acute pancreatitis,which is likely induced by the same pathophysiological mechanisms as after en-doscopic retrograde cholangiopancreatography(ERCP).According to the current European Society of Gastrointestinal Endoscopy guideline,nonsteroidal anti-inflammatory drugs are administered prior to ERCP as a scientifically proven treatment to reduce post-ERCP pancreatitis incidence rate.A single suppository of diclofenac or indomethacin prior to EUS guided tissue acquisition(TA)is harm-less in healthy adults.Since it is associated with low costs and,most important,may prevent a dreadsome complication,we strongly recommend the adminis-tration of 100 mg diclofenac rectally prior to EUS-TA.We will explain this recom-mendation in more detail in this review as well as the risk and pathophysiology of post-EUS TA pancreatitis.

A Comprehensive Survey on Advanced Persistent Threat (APT) Detection Techniques

The increase in number of people using the Internet leads to increased cyberattack opportunities.Advanced Persistent Threats,or APTs,are among the most dangerous targeted cyberattacks.APT attacks utilize various advanced tools and techniques for attacking targets with specific goals.Even countries with advanced technologies,like the US,Russia,the UK,and India,are susceptible to this targeted attack.APT is a sophisticated attack that involves multiple stages and specific strategies.Besides,TTP(Tools,Techniques,and Procedures)involved in the APT attack are commonly new and developed by an attacker to evade the security system.However,APTs are generally implemented in multiple stages.If one of the stages is detected,we may apply a defense mechanism for subsequent stages,leading to the entire APT attack failure.The detection at the early stage of APT and the prediction of the next step in the APT kill chain are ongoing challenges.This survey paper will provide knowledge about APT attacks and their essential steps.This follows the case study of known APT attacks,which will give clear information about the APT attack process—in later sections,highlighting the various detection methods defined by different researchers along with the limitations of the work.Data used in this article comes from the various annual reports published by security experts and blogs and information released by the enterprise networks targeted by the attack.

Rule acquisition of three-way semi-concept lattices in formal decision context

Three-way concept analysis is an important tool for information processing,and rule acquisition is one of the research hotspots of three-way concept analysis.However,compared with three-way concept lattices,three-way semi-concept lattices have three-way operators with weaker constraints,which can generate more concepts.In this article,the problem of rule acquisition for three-way semi-concept lattices is discussed in general.The authors construct the finer relation of three-way semi-concept lattices,and propose a method of rule acquisition for three-way semi-concept lattices.The authors also discuss the set of decision rules and the relationships of decision rules among object-induced three-way semi-concept lattices,object-induced three-way concept lattices,classical concept lattices and semi-concept lattices.Finally,examples are provided to illustrate the validity of our conclusions.