基于HOCs和LOCs的大学英语写作教学模式研究——以应用型本科院校大学英语教学为例

本文在Higher Order Concerns(HOCs) 和 Lower Order Concerns(LOCs)系统概念指导下,通过对实验写作文本采集与分析,结合HOCs和LOCs写作分类系统,提出大学英语写作教学阶梯式分级教学模式,旨在分层、系统地进行大学英语写作知识教授与技能训练,打造大学英语写作教学金课,提高学生大学英语书面表达能力。

acSB:Anti-Collision Selective-Based Broadcast Protocol in CRAdHocs

As a fundamental operation in ad hoc networks,broadcast could achieve efficient message propagations.Particularl y in the cognitive radio ad hoc network where unlicensed users have different sets of available channels,broadcasts are carried out on multiple channels.Accordingly,channel selection and collision avoidance are challenging issues to balance the efficiency against the reliability of broadcasting.In this paper,an anticollision selective broadcast protocol,called acSB,is proposed.A channel selection algorithm based on limited neighbor information is considered to maximize success rates of transmissions once the sender and receiver have the same channel.Moreover,an anticollision scheme is adopted to avoid simultaneous rebroadcasts.Consequently,the proposed broadcast acSB outperforms other approaches in terms of smaller transmission delay,higher message reach rate and fewer broadcast collisions evaluated by simulations under different scenarios.

紫外光非直视通信研究进展

紫外光技术在军事和民用领域有着广泛的应用,如空间探测、紫外光制导、紫外干扰、电晕放电检测和军事通信等领域。文章从紫外光的单次和多次散射出发,介绍了紫外光通信的国内外进展,分析了紫外光通信中的不同链路情况,针对非直视链路紫外通信的脉冲展宽效应和大气湍流影响进行了探讨,总结了紫外光Ad Hoc网络,最后对紫外光通信的发展进行了展望。

面向差异化业务保障的自适应信道预约多址接入协议

在无中心节点网络中可能存在不同类型的业务,部分高优先级业务具有严格的时延等服务质量(quality of service,QoS)需求。但当网络负载较重时,冲突概率明显提高,使得这些业务的需求难以得到保障,如何设计高效的多址接入协议以保证不同种类业务的服务质量是重要的研究方向。信道预约机制是保证QoS的重要方法,但现有信道预约机制对多种业务服务时,通常没有根据服务质量需求和网络状况精细调整预约参数。因此针对以上问题提出了一种面向差异化业务保障的信道预约MAC协议(differentiated service guarantee adaptive reservation mechanism,DSGARM),协议核心思想是针对每种业务的容忍时延需求和网络状况精细提供差异化服务,协议中通过建立的数学模型设计自适应算法,定量计算出满足时延需求的预约参数,能够根据网络状况自适应调整合适的预约参数以保障每一类业务的时延需求。仿真结果说明了提出协议的优势,具有较大的实际意义。

近距无线通信组网拓扑技术

针对精确制导武器的新质作战需求,文中以无线电气设计为核心技术方向实现产品模块化设计,以解决灵活组网、抗毁重构和动态拓扑等问题。采用Ad Hoc组网架构、广义编码和无源多址接入技术,实现快速、灵活、稳定的信息交互。通过混合式路由设计,在金属舱网络中划分子网并实施先应式路由和反应式路由,并引入地界标思想以减少多制式通信影响。通过提前规定所有事件的时序和优先级,建立简易事件类型库,并在节点间备份存储,同时采用边界广播协议实现目的节点快速抵达网关节点。研究结果表明,所提方案满足了武器功能模块化设计的需求,通过无线通信网络的组网和路由协议设计,实现了灵活组网、抗毁重构、动态拓扑和多制式通信等能力特点。

A Multi-Token Sector Antenna Neighbor Discovery Protocol for Directional Ad Hoc Networks

In this paper,we propose a Multi-token Sector Antenna Neighbor Discovery(M-SAND)protocol to enhance the efficiency of neighbor discovery in asynchronous directional ad hoc networks.The central concept of our work involves maintaining multiple tokens across the network.To prevent mutual interference among multi-token holders,we introduce the time and space non-interference theorems.Furthermore,we propose a master-slave strategy between tokens.When the master token holder(MTH)performs the neighbor discovery,it decides which 1-hop neighbor is the next MTH and which 2-hop neighbors can be the new slave token holders(STHs).Using this approach,the MTH and multiple STHs can simultaneously discover their neighbors without causing interference with each other.Building on this foundation,we provide a comprehensive procedure for the M-SAND protocol.We also conduct theoretical analyses on the maximum number of STHs and the lower bound of multi-token generation probability.Finally,simulation results demonstrate the time efficiency of the M-SAND protocol.When compared to the QSAND protocol,which uses only one token,the total neighbor discovery time is reduced by 28% when 6beams and 112 nodes are employed.

Secure and Reliable Routing in the Internet of Vehicles Network:AODV-RL with BHA Attack Defense

Wireless technology is transforming the future of transportation through the development of the Internet of Vehicles(IoV).However,intricate security challenges are intertwinedwith technological progress:Vehicular ad hoc Networks(VANETs),a core component of IoV,face security issues,particularly the Black Hole Attack(BHA).This malicious attack disrupts the seamless flow of data and threatens the network’s overall reliability;also,BHA strategically disrupts communication pathways by dropping data packets from legitimate nodes altogether.Recognizing the importance of this challenge,we have introduced a new solution called ad hoc On-Demand Distance Vector-Reputation-based mechanism Local Outlier Factor(AODV-RL).The significance of AODVRL lies in its unique approach:it verifies and confirms the trustworthiness of network components,providing robust protection against BHA.An additional safety layer is established by implementing the Local Outlier Factor(LOF),which detects and addresses abnormal network behaviors.Rigorous testing of our solution has revealed its remarkable ability to enhance communication in VANETs.Specifically,Our experimental results achieve message delivery ratios of up to 94.25%andminimal packet loss ratios of just 0.297%.Based on our experimental results,the proposedmechanismsignificantly improves VANET communication reliability and security.These results promise a more secure and dependable future for IoV,capable of transforming transportation safety and efficiency.

A Review on the Recent Trends of Image Steganography for VANET Applications

Image steganography is a technique of concealing confidential information within an image without dramatically changing its outside look.Whereas vehicular ad hoc networks(VANETs),which enable vehicles to communicate with one another and with roadside infrastructure to enhance safety and traffic flow provide a range of value-added services,as they are an essential component of modern smart transportation systems.VANETs steganography has been suggested by many authors for secure,reliable message transfer between terminal/hope to terminal/hope and also to secure it from attack for privacy protection.This paper aims to determine whether using steganography is possible to improve data security and secrecy in VANET applications and to analyze effective steganography techniques for incorporating data into images while minimizing visual quality loss.According to simulations in literature and real-world studies,Image steganography proved to be an effectivemethod for secure communication on VANETs,even in difficult network conditions.In this research,we also explore a variety of steganography approaches for vehicular ad-hoc network transportation systems like vector embedding,statistics,spatial domain(SD),transform domain(TD),distortion,masking,and filtering.This study possibly shall help researchers to improve vehicle networks’ability to communicate securely and lay the door for innovative steganography methods.

情境目标和Ad hoc关联影响言语产生的语义效应

干扰词与目标词之间的语义关联性是影响言语产生中语义效应性质的关键因素。相比其他语义关联类型,Ad hoc关联是一种较为特殊的概念联系类型。考察情境目标和Ad hoc关联对语义效应的影响,结果表明:与其他语义关联性相比,Ad hoc关联对语义效应的影响既有共性,又有差异。共性表现在:Ad hoc关联抑制图片命名,产生语义干扰效应,这种效应发生在图片命名早期(SOA从-200ms至0ms)。差异表现在:Ad hoc关联的语义干扰效应的产生要以情境目标提示为前提,有情境目标提示时,Ad hoc关联效应非常显著;无情境目标提示时,Ad hoc关联效应消失。不同语义关联类型产生不同语义效应的根源在于类别概念结点是否得到激活。

Trust-based Intelligent Scheme for Mitigating Black Hole Attacks in IoT

Internet of Things(IoT)networks are characterized by a multitude of wireless,interconnected devices that can dynamically join or exit the network without centralized administration or fixed infrastructure for routing.While multipath routing in IoT networks can improve data transmission reliability and load balancing by establishing multiple paths between source and destination nodes,these networks are susceptible to security threats due to their wireless nature.Traditional security solutions developed for conventional networks are often ill-suited to the unique challenges posed by IoT environments.In response to these challenges,this paper proposes the integration of the Ad hoc On-demand Multipath Distance Vector(AOMDV)routing protocol with a trust model to enhance network performance.Key findings from this research demonstrate the successful fusion of AOMDV with a trust model,resulting in tangible improvements in network performance.The assessment of trustworthiness bolsters both security and routing capabilities in IoT networks.The trust model plays a crucial role in mitigating black hole attacks in IoT networks by evaluating the trustworthiness of nodes and helping in the identification and avoidance of malicious nodes that may act as black holes.Simulation results validate the efficacy of the proposed trust-based routing mechanism in achieving its objectives.Trust plays a pivotal role in decision-making and in the creation of secure distribution systems.By assessing the trustworthiness of nodes,both network security and routing efficiency can be enhanced.The effectiveness of the proposed trust-based routing mechanism is scrutinized through simulations,offering insights into its potential advantages in terms of improved network security and routing performance in the context of the IoT.

Ad Hoc网络AODV协议的黑洞攻击防御研究

Ad Hoc网络,又名多跳网、无基础设施网或自组织网,是一种没有核心、独立运作的WiFi。目前,Ad Hoc路由协议的主要种类包括DSDV、WRR、DSR、DODV和TORA等。AODV在Ad Hoc网络里被广泛应用,这是一种根据需求、迅速调整、成本较低并能够实现多次传输的路由算法。Ad Hoc网络遭受的关键安全威胁有被盗听、DoS入侵、“睡眠”攻击、数据伪造、反向传输以及黑客入侵等。本文对Zapata、Hongmei Deng等学者的下游节点验证算法进行详细的阐述,并且提出一种基于反馈ACK的OSAODV算法,该算法能够有效地对抗黑洞的威胁。

基于表驱动的路由协议设计与FPGA实现

针对ad hoc网络的拓扑可变性,设计了一种基于表驱动的网络路由协议。该路由协议中的每个节点维护一个拓扑集和一张到其他节点的路由表,当网络的拓扑结构变化时,各节点实时更新网络的拓扑项和路由表。同时在FPGA上实现了一种基于有限状态机(FSM)的路由表管理。经验证,该路由协议可以快速响应拓扑的变化,路由时延低,硬件资源占用少且功耗小。

移动Ad Hoc云中基于能量收集的分布式卸载方案研究

在物联网快速发展的驱动下,移动Ad Hoc云计算和能量收集(EH)技术通过共享邻近设备的闲置资源满足数据处理等需求,实现绿色通信。然而,由于Ad Hoc云网络的时变性以及EH的随机不稳定性,合理的任务卸载方案研究面临着严峻的挑战。针对以上问题,该文运用Lyapunov优化理论和博弈论,提出一种分布式动态卸载方案。理性的终端设备不可能无偿地为其他终端设备服务,为了鼓励终端设备积极参与计算卸载过程,提出一种基于动态报价的激励机制。相比于现有方案,仿真结果表明所提方案可以有效提升系统收益,稳定电池能量和减少任务队列积压。

Ad hoc网络中基于区块链技术的多路径路由算法研究

本文在Ad hoc网络中提出了一种基于区块链技术的多路径QoS(quantity of service)路由算法(BMQR)。该算法依据网络内节点的移动性、连通性和通信距离组建类似区块群,在群内通过QoS约束寻找由主节点和备选节点组成的多路径路由。通过实验仿真,BMQR算法较传统的AODV(Ad hoc on-demand distance vector routing)算法在路由的稳定性和投包率方面展示出了巨大的优越性。

基于ZYNQ-7000平台无线自组网按需距离矢量路由协议实现研究

为了使无线自组网按需距离矢量路由协议(Ad hoc On-demand distance vector routing,AODV)能够在高版本的Linux系统中运行,针对AODV协议在嵌入式平台中的实际应用问题,提出了一种基于嵌入式Linux-4.14系统的AODV协议的实现方法。根据Linux系统的内核版本对AODV-UU中内核层以及用户层中的功能模块进行设计,通过搭建Ad Hoc网络对协议的通信性能进行测试。测试结果表明,在实际通信过程中节点之间的平均丢包率为0.4%,平均往返时间为27 ms,具有良好的通信稳定性与及时性。

An aerial ammunition ad hoc network collaborative localization algorithm based on relative ranging and velocity measurement in a highly-dynamic topographic structure

In the internet of battlefield things, ammunition is becoming networked and intelligent, which depends on location information. Therefore, this paper focuses on the self-organized network collaborative localization of munitions with an aerial three-dimensional(3D) highly-dynamic topographic structure under a satellite denied environment. As for aerial networked munitions, the measurement of munitions is objectively incomplete due to the degenerated and interrupted link of munitions. For this reason, a cluster-oriented collaborative localization method is put forward in this paper. Multidimensional scaling(MDS) was first integrated with a trilateration localization method(TLM) to construct a relative localization algorithm for determining the relative location of a mobile cluster network. The information related to relative velocity was then combined into a collaborative localization framework to devise a TLM-vMDS algorithm. Finally, an iterative refinement algorithm based on scaling by majorizing a complicated function(SMACOF) was employed to effectively eliminate the influence of incomplete link observation on localization accuracy. Compared with the currently available advanced algorithms, the proposed TLM-vMDS algorithm achieves higher localization accuracy and faster convergence for a cluster of extensively networked munitions, and also offers better numerical stability and robustness for highspeed motion models.

基于HTTP协议的Ad hoc网络信息泄露点快速检测

由于Ad hoc网络遭受攻击后,网络信息存在泄露问题,难以准确分析出网络流量,并且泄露点检测速度较慢,在检测后用户的攻击效率仍然较高,为此,基于HTTP协议研究了一种新的Ad hoc网络信息泄露点快速检测方法。在信息与节点属性检测下,通过信息传输模型分析信息泄露状况,计算两个节点之间信息泄露概率,确定Ad hoc网络信息泄露链路,获取信息可能泄露的途径。并通过HTTP协议连接客户端,将泄露链路数据指令传输给客户端,客户端再通过接收的指令,对信息泄露链路中的泄露点进行检测,采用小波重构对网络信息泄露时的网络信号进行重构,将重构后的信号与正常信号进行对比,设定阈值,通过阈值判定的形式,完成Ad hoc网络信息泄露点快速检测。实验结果表明,所提方法能够精准地分析出网络流量变化状况,提升泄露点检测速度,降低用户攻击效率,保证网络安全。

无线Ad hoc网络路由技术研究与应用分析

给出Ad hoc网络路由协议的分类,分析经典的路由算法在不同场景中的应用,并进行了性能比较,开展Ad hoc网络路由接口技术研究和分析。

Critical Nodes Identification: A Non-Cooperative Method for Unknown Topology Information in Ad Hoc Networks

The foundation of ad hoc networks lies in the guarantee of continuous connectivity.However,critical nodes,whose failure can easily destroy network connectivity,will influence the ad hoc network connectivity significantly.To protect the network efficiently,critical nodes should be identified accurately and rapidly.Unlike existing critical node identification methods for unknown topology that identify critical nodes according to historical information,this paper develops a critical node identification method to relax the prior topology information condition about critical nodes.Specifically,we first deduce a theorem about the minimum communication range for a node through the number of nodes and deployment ranges,and prove the universality of the theorem in a realistic two-dimensional scenario.After that,we analyze the relationship between communication range and degree value for each node and prove that the greater number of nodes within the communication range of a node,the greater degree value of nodes with high probability.Moreover,we develop a novel strategy to improve the accuracy of critical node identification without topology information.Finally,simulation results indicate the proposed strategy can achieve high accuracy and low redundancy while ensuring low time consumption in the scenarios with unknown topology information in ad hoc networks.

Secure and Energy Concise Route Revamp Technique in Wireless Sensor Networks

Energy conservation has become a significant consideration in wireless sensor networks(WSN).In the sensor network,the sensor nodes have internal batteries,and as a result,they expire after a certain period.As a result,expanding the life duration of sensing devices by improving data depletion in an effective and sustainable energy-efficient way remains a challenge.Also,the clustering strategy employs to enhance or extend the life cycle of WSNs.We identify the supervisory head node(SH)or cluster head(CH)in every grouping considered the feasible strategy for power-saving route discovery in the clustering model,which diminishes the communication overhead in the WSN.However,the critical issue was determining the best SH for ensuring timely communication services.Our secure and energy concise route revamp technology(SECRET)protocol involves selecting an energy-concise cluster head(ECH)and route revamping to optimize navigation.The sensors transmit information over the ECH,which delivers the information to the base station via the determined optimal path using our strategy for effective data transmission.We modeled our methods to accom-plish power-efficient multi-hop routing.Furthermore,protected navigation helps to preserve energy when routing.The suggested solution improves energy savings,packet delivery ratio(PDR),route latency(RL),network lifetime(NL),and scalability.