Adaptive Antenna-Activation Based Beamforming for Large-Scale MIMO Communication Systems of High Speed Railway

Large-scale array aided beamforming improves the spectral efficiency(SE) as a benefit of high angular resolution.When dual-beam downlink beamforming is applied to the train moving towards cell edge,the inter-beam ambiguity(IBA) increases as the directional difference between beams becomes smaller.An adaptive antenna activation based beamforming scheme was proposed to mitigate IBA.In the district near the base station(BS),all antenna elements(AEs) were activated to generate two beams.As the distance from the train to the BS increased,only the minimum number of AEs satisfying the resolution criterion would be activated.At the cell edge,one beam was switched off due to intolerable IBA.The proposed scheme can achieve SE gain to the non-adaptive scheme and show more robustness against the direction-of-arrival(DOA) estimation error.

IMPLEMENTING SECURITY FOR ACTIVE NETWORKS IN INTERNET

Active networks is primarily a Defense Advanced Research Projects Agency(DARPA)-funded project focusing on the research of mechanisms, applications, and operating systems to develop a reconfigurable network infrastructure. This letter proposes an Secure Active Tracing System (SATS) to implementing security for active networking in Internet. Unlike currently existing schemes, SATS reduces the computational overloads by executing the filtering operation on selected packet streams only when needed.

Public Security Risk m Large Scale Activities and the Standardization Prospects

This paper generalizes the definition and its scope of large scale activity based on its current practice and supervision system in China, makes risk analysis during activities, and puts forward proposals on carrying out relevant standardization works after discussions about the actuality and prospect of social security on large scale activities in China.

Review of dynamics and active control of large-scale space membrane antenna

Large-scale space membrane antennas have significant potential in satellite communication,space-based early warning,and Earth observation.Because of their large size and high flexibility,the dynamic analysis and control of membrane antenna are challenging.To maintain the working performance of the antenna,the pointing and surface accuracies must be strictly maintained.Therefore,the accurate dynamic modeling and effective active control of large-scale space membrane antennas have great theoretical significance and practical value,and have attracted considerable interest in recent years.This paper reviews the dynamics and active control of large-scale space membrane antennas.First,the development and status of large-scale space membrane antennas are summarized.Subsequently,the key problems in the dynamics and active control of large membrane antennas,including the dynamics of wrinkled membranes,large-amplitude nonlinear vibration,nonlinear model reduction,rigid-flexible-thermal coupling dynamic modeling,on-orbit modal parameter identification,active vibration control,and wave-based vibration control,are discussed in detail.Finally,the research outlook and future trends are presented.

Large-scale circulation features associated with the heat wave over Northeast China in summer 2018

In late July and early August 2018,Northeast China suffered from extremely high temperatures,with the maxium temperature anomaly exceeding 6°C.In this study,the large-scale circulation features associated with this heat wave over Northeast China are analyzed using station temperature data and NCEP–NCAR reanalysis data.The results indicate that strong anomalous positive geopotential height centers existed from the lower to upper levels over Northeast China,and the related downward motions were directly responsible for the extreme high-temperature anomalies.The northwestward shift of the western Pacific subtropical high(WPSH)and the northeastward shift of the South Asian high concurrently reinforced the geopotential height anomalies and descending flow over Northeast China.In addition,an anomalous Pacific–Japan pattern in the lower troposphere led to the northwestward shift of the WPSH,jointly favoring the anomalous geopotential height over Northeast China.Two wave trains emanating from the Atlantic region propagated eastwards along high latitudes and midlatitudes,respectively,and converged over Northeast China,leading to the enhancement of the geopotential height anomalies.

Ensuring water security by utilizing roof-harvested rainwater and lake water treated with a low-cost integrated adsorption-filtration system

Drinking water is supplied through a centralized water supply system and may not be accessed by communities in rural areas of Malaysia.This study investigated the performance of a low-cost, self-prepared combined activated carbon and sand filtration(CACSF) system for roofharvested rainwater and lake water for potable use. Activated carbon was self-prepared using locally sourced coconut shell and was activated using commonly available salt rather than a high-tech procedure that requires a chemical reagent. The filtration chamber was comprised of local,readily available sand. The experiments were conducted with varying antecedent dry intervals(ADIs) of up to 15 d and lake water with varying initial chemical oxygen demand(COD) concentration. The CACSF system managed to produce effluents complying with the drinking water standards for the parameters p H, dissolved oxygen(DO), biochemical oxygen demand(BOD5), COD, total suspended solids(TSS), and ammonia nitrogen(NH_3-N). The CACSF system successfully decreased the population of Escherichia coli(E. coli) in the influents to less than 30 CFU/m L. Samples with a higher population of E. coli(that is, greater than 30 CFU/m L) did not show 100% removal. The system also showed high potential as an alternative for treated drinking water for roof-harvested rainwater and class II lake water.

Joint Trajectory and Power Optimization for Securing UAV Communications Against Active Eavesdropping

Due to both of jamming and eavesdropping,active eavesdroppers can induce more serious security threats to unmanned aerial vehicle(UAV)-enabled communications.This paper considers a secure UAV communication system including both the downlink(DL)and uplink(UL)transmissions,where the confidential information is transmitted between a UAV and a ground node in the presence of an active eavesdropper.We aim to maximize the average secrecy rates of the DL and UL communications,respectively,by jointly optimizing the UAV trajectory and the UAV/ground node’s transmit power control over a given flight period.Due to the non-convexity of the formulated problems,it is difficult to obtain globally optimal solutions.However,we propose efficient iterative algorithms to obtain high-quality suboptimal solutions by applying the block coordinate descent and successive convex optimization methods.Simulation results show that the joint optimization algorithms can effectively improve the secrecy rate performance for both the DL and UL communications,as compared with other baseline schemes.The proposed schemes can be considered as special cases of UAV-assisted non-orthogonal multiple access(NOMA)networks.

A Survey of Security Issues in Cognitive Radio Networks

In the last decade,cognitive radio(CR) has emerged as a major next generation wireless networking technology,which is the most promising candidate solution to solve the spectrum scarcity and improve the spectrum utilization.However,there exist enormous challenges for the open and random access environment of CRNs,where the unlicensed secondary users(SUs) can use the channels that are not currently used by the licensed primary users(PUs) via spectrum-sensing technology.Because of this access method,some malicious users may access the cognitive network arbitrarily and launch some special attacks,such as primary user emulation attack,falsifying data or denial of service attack,which will cause serious damage to the cognitive radio network.In addition to the specifi c security threats of cognitive network,CRNs also face up to the conventional security threats,such as eavesdropping,tampering,imitation,forgery,and noncooperation etc..Hence,Cognitive radio networks have much more risks than traditional wireless networks with its special network model.In this paper,we considered the security threats from passive and active attacks.Firstly,the PHY layer security is presented in the view of passive attacks,and it is a compelling idea of using the physical properties of the radio channel to help provide secure wireless communications.Moreover,malicious user detection is introduced in the view of active attacks by means of the signal detection techniques to decrease the interference and the probabilities of false alarm and missed detection.Finally,we discuss the general countermeasures of security threats in three phases.In particular,we discuss the far reaching effect of defensive strategy against attacks in CRNs.

A Cluster-Based Secure Active Network Environment

We introduce a cluster-based secure active network environment (CSANE) which separates the processing of IP packets from that of active packets in active routers. In this environment, the active code authorized or trusted by privileged users is executed in the secure execution environment (EE) of the active router, while others are executed in the secure EE of the nodes in the distributed shared memory (DSM) cluster. With the supports of a multi-process Java virtual machine and KeyNote, untrusted active packets are controlled to securely consume resource. The DSM consistency management makes that active packets can be parallely processed in the DSM cluster as if they were processed one by one in ANTS (Active Network Transport System). We demonstrate that CSANE has good security and scalability, but imposing little changes on traditional routers.

Assessment of Nutrient Composition and Antioxidant Activity of Some Popular Underutilized Edible Crops of Nagaland, India

In Nagaland ~70% of population lives in rural areas and depends on forest products for livelihood. Being part of the biodiversity hotspot, state is rich in biodiversity. The present study was an attempt made to understand the nutritional properties of 22 popular underutilized edible plants (UEP) Kohima, Phek, Tuensang districts. Results revealed moisture content of 22 studied plants ranged between 4.8 to 88.15 g/100g, while protein content varied between 0.00269 - 0.773 g/100g with highest in Terminalia chebula (0.773 g/100g) fruit while lowest protein content was in Setaria italica (0.00269 g/100g). Total carbohydrate content was between 0.198 - 5.212 g/100g with highest in Setaria italica (5.212 g/100g) and lowest in Juglans regia (0.198 g/100g). Of the 22 samples, maximum antioxidant activity was in Terminalia chebula fruits (37.49 μg/ml) followed by Clerodendrum glandulosum (65.29 μg/ml) leaves, Phyllanthus emblica (79.08 μg/ml) fruits against Trolox (96.89 μg/ml). Highest total phenol content (TPC) was recorded in Terminalia chebula (53.11 mg GAE/g) and Rhus chinensis (43.99 mg GAE/g) while in other 20 crops the values varied from 0.09 - 8.44 mg GAE/g. Total flavonoid content (TFC) varied between 0.004 - 43.67 mg QE/g with clerodendrum glandulosum (43.67 mg QE/g) and Terminalia chebula (27.78 mg QE/g) were found to be highest among the 22 plant samples. Findings suggest that these underutilized edible plants should be popularized as they can contribute to nutritional support to different region of the state for health improvement and cultivated them commercially to help and develop various value added local product to improve the livelihood status of the rural population and also add to the economy of the state and region.

Cyberspace Security Using Adversarial Learning and Conformal Prediction

This paper advances new directions for cyber security using adversarial learning and conformal prediction in order to enhance network and computing services defenses against adaptive, malicious, persistent, and tactical offensive threats. Conformal prediction is the principled and unified adaptive and learning framework used to design, develop, and deploy a multi-faceted?self-managing defensive shield to detect, disrupt, and deny intrusive attacks, hostile and malicious behavior, and subterfuge. Conformal prediction leverages apparent relationships between immunity and intrusion detection using non-conformity measures characteristic of affinity, a typicality, and surprise, to recognize patterns and messages as friend or foe and to respond to them accordingly. The solutions proffered throughout are built around active learning, meta-reasoning, randomness, distributed semantics and stratification, and most important and above all around adaptive Oracles. The motivation for using conformal prediction and its immediate off-spring, those of semi-supervised learning and transduction, comes from them first and foremost supporting discriminative and non-parametric methods characteristic of principled demarcation using cohorts and sensitivity analysis to hedge on the prediction outcomes including negative selection, on one side, and providing credibility and confidence indices that assist meta-reasoning and information fusion.

基于主动探测的Web容器探测识别方法

随着工业互联网的飞速发展,各类Web容器的广泛使用呈现不断增长的趋势,然而,这也使得Web容器资产管理的问题变得更加复杂.随之而来的是诸多网络安全风险和潜在隐患,对于这些挑战,提升网络安全防御水平显得尤为迫切.为了解决这一问题,本文引入了一种新的基于主动探测的Web容器探测识别方法.在探测阶段,采用了一种先进的Web容器探针构建方法,通过此方法构建了Web容器探针.这个探针在识别阶段发挥关键作用,借助一种基于负载内容的Web容器识别方法,通过协议解码技术,实现了对Web容器的高度准确的识别.通过结合这两种先进的识别方法,成功识别了4种不同类型的Web容器,并且提升了精度,能够精确地区分这些Web容器的各个版本,总计实现了10个版本的准确识别.通过这种先进的主动探测方法,企业可以更好地了解和管理其Web容器资产,降低网络安全风险,并确保网络系统的稳定性和安全性.

攻防对抗视角下的网络安全主动防御体系研究

为了解决纵深防御体系中防御能力固化、灵活性不足等问题,从攻防对抗视角出发,提出一种网络安全主动防御体系。首先,基于情报收集、监测预警、防御指挥和防御行动等要素的详细描述,设计了用于规划主动防御系统的能力组成框架;其次,选择网络杀伤链、ATT&CK知识库和OODA循环法则,设计了一个以攻助防的防御模型,并分析了引入博弈论进行防御算法设计的优势;最后,以实现为目标,构想了一个典型应用场景,以期为安全能力的体系化设计提供有益借鉴。

外空安全与环境治理:进展、挑战与机遇

随着人类航天活动的迅猛发展,外空环境日益复杂无序,外空安全的威胁显著上升,外层空间长期可持续性面临严重挑战。本文全面介绍了外空安全面临的最新态势,系统分析了空间碎片数量逐年增多、低轨大规模星座迅猛部署、新型航天活动快速喷发、外空资源争夺日趋激烈、外空军事化愈演愈烈等对外空安全和外空长期可持续的冲击。本文指出,从外空命运共同体、国家空间资产安全、航天强国建设出发,外空环境治理是大势所趋和唯一出路,孕育着航天技术创新、产业革命、法规建制等重大机遇。基于国情提出了我国对策和发展建议。

网络恐怖活动的刑事规制及多元打防机制

当前,我国虽然对恐怖活动进行了法律规制,但尚有完善空间。不同于传统型恐怖活动,网络恐怖活动具有犯罪主体新型化、犯罪工具现代化、实施手段隐蔽化等诸多特征,呈现出肆虐全球的严峻态势。在总体国家安全观下,应当充分发挥法治在反网络恐怖主义犯罪领域的基础性作用,从立法、执法、司法等领域多维度切入,逐步解除治理网络恐怖活动所面临的现实难题。在现有犯罪治理法律体系下,采取更加积极有效的管控措施,将网络恐怖活动纳入刑法规制范畴之内,实现对网络恐怖活动的有效刑事规制。另外,还要建立起打击网络恐怖活动的多元机制,包括信息共享、全球联动、群防群控等。

混合可重构智能表面和人工噪声辅助的物理层安全通信

针对可重构智能表面(Reconfigurable Intelligent Reflecting Surface,RIS)辅助的物理层安全通信,该文设计了基于混合有源-无源RIS和人工噪声(Artificial Noise,AN)辅助的安全传输方案。考虑基站和RIS的功率约束以及RIS无源反射元件的反射系数恒模约束,以最大化系统安全传输速率为目标,构建基站发射波束成形、AN波束向量、RIS反射系数矩阵联合优化问题。使用交替优化(Alternating Optimization,AO)、权值最小均方误差(Weighted Minimum Mean Square Error,WMMSE)和半定松弛(Semi-definite Relaxation,SDR)算法,求解所构建的变量高度耦合的非凸优化问题。仿真结果表明,混合RIS辅助安全传输方案,能够有效提高系统的安全速率,与无源RIS相比,能够有效克服“双衰落”效应导致的安全速率降低,与有源RIS相比,具有更高的能量效率。

基于KAP理论的大学生网络安全教育研究

为改善大学生网络安全教育现状,提高大学生网络安全教育水平,结合知识-态度-行为(KAP)理论,构建大学生安全教育KAP模型;通过问卷发放和筛选,获取659份有效问卷;采用结构方程模型(SEM)检验网络安全教育对网络安全认知、网络安全态度、网络安全行为的影响,以及可能存在的中介作用影响路径。结果表明:网络安全教育显著影响网络安全认知、网络安全态度、网络安全行为,其中,网络安全认知、网络安全态度起到独立中介及链式中介作用;法律道德教育、知识教育、实践活动、榜样引领均能直接影响网络安全行为,其中,法律道德教育对网络安全行为的影响最强,知识教育次之,实践活动和榜样引领最弱。在具体作用路径方面,法律道德教育主要通过直接效应来影响网络安全行为,知识教育、实践活动、榜样引领主要通过安全认知间接影响网络安全行为。

论生物安全风险刑法规制之保护法益

风险视域下《中华人民共和国刑法修正案(十一)》针对部分生物安全犯罪行为进行了回应,扩大了刑法对生物安全的保护范围。然而,刑事立法将生物安全犯罪的主要保护法益归结为传统公共卫生法益并不合适。传统公共卫生法益的“低政治”技术指标属性和“人类中心主义”规范视角导致刑法在规制生物安全风险方面存在位阶失衡、射程失准和功能失范的问题。法益理论的落后带来的是罪与非罪、此罪与彼罪的混乱。因此生物安全的法益认定应坚持积极预防主义,积极预防主义具有正当性、可操作性、协调性。同时基于法益保护早期化、抽象化的积极预防主义理念,在法益内涵上应当确立生物安全法益乃是一种新型复合法益,不仅包括通常的生命、健康法益,还包括集防范自然生物风险的生物安保价值和防范人为生物风险的生物防御价值于一体的“总体国家安全”以及包括人之自主性、目的性、平等性的“人类尊严”等抽象法益。