Aiming at the problems of unreachable search target, weak path finding and obstacle avoidance ability, and slow algorithm convergence speed when dealing with the 3D path planning of autonomous underwater vehicles (AUV) in the traditional cuckoo algorithm in complex waters, an AUV path planning algorithm PSO-ASCS (Particle Swarm Optimization-Adaptive Step-size Cuckoo Search Algorithm) is proposed, which combines the improved Adaptive Step-size Cuckoo Search and Particle Swarm Optimization. This research uses the idea of spatial layering to establish a three-dimensional model of complex waters to conduct path planning and obstacle avoidance experiments on the PSO-ASCS algorithm; The PSO-ASCS algorithm is tested and compared with the adaptive step size cuckoo search algorithm, standard cuckoo algorithm and particle swarm optimization by constructing a fitness function considering the three factors of path length, path smoothness and path hazard. Experiments show that the improved algorithm has strong global search ability and optimization performance, and the algorithm converges well, so that the AUV has the ability of efficient obstacle avoidance and path planning.
在传统的图像描述生成任务中，已有方法对图像的描述仅仅停留在浅层，并缺乏真实世界知识的指导，难以挖掘出对象在特定背景下的逻辑语义关系。新闻文本的引入为图像描述带来了新的可能，同时对模型的学习能力有了更高要求；此外，新闻图集中往往存在多幅图像，且相互之间联系紧密，导致现有单图描述生成方法不适用于新闻图集描述生成。针对上述问题，本文提出了一种基于图文双向引导注意力（image and text bidirectional guidance attention,ITBGA）的新闻图集描述方法，以图集作为研究对象，并辅以对应的新闻文本作为背景知识，基于ITBGA分别实现粗、细两个粒度的跨模态信息交互，并通过指针网络辅助命名实体词生成。在本文构建的新闻图集数据集上进行了实验验证，结果表明ITBGA能有效提升描述文本的质量，在关键的CIDEr指标上达到了最优。
Aiming at the problems of weak keys,low security and many loopholes in the lightweight cryptography and authentica-tion protocols used in most authentication models of the Internet of Things,a multi-factor enhanced authentication model was pro-posed based on zero-knowledge proof.The model was composed of one-way one-time computing type tasks,and combines vari-ous consensus verification technologies to form a multi-factor consensus verification method.And through the distributed consen-sus mechanism of the blockchain architecture,the enhanced processing function of multi-factor one-time difficult tasks had been re-alized.At the same time,flexible access control and privacy protection were realized by dynamically setting the type of evidence in the token.Finally,a simulation experiment was carried out to verify,and a prototype scene was constructed for the offline smart lock scene.Experimental results show that the model implements concise peer-to-peer verification of dynamic difficulty policies,exhibiting millisecond-level high performance and flexibility.Compared with other IoT authentication models,it has better securi-ty and practicality.
Aiming at the problem that the whole network topology information of the new power system Internet of Things is man aged in a decentralized manner by taking power plants and stations(including power plants,substations,renewable energy power plants,virtual power plant,etc).Firstly,a topology analysis method for power plants based on switch path function was proposed.Secondly,the rules for decentralized coordination of plant and station information were proposed,and an improved switch path function method for adjacent plant and station topology analysis was proposed,as well as a method for achieving full network topology analysis through plant and station decentralization.Finally,the feasibility of the proposed method was demonstrated through simulation of an actual new power system.
To address the vulnerability of the CAN(controller area network)bus in Telematics,this paper proposes a hybrid attack intrusion detection model,DGAO-IDS,which uses an unsupervised DBN to learn the basic features of normal CAN message data and a GRU network with an attention mechanism to learn its temporal features,and finally classifies them using a single classification support vector machine.The final detection result is obtained by combining the filter with the classification results of the aforementioned model.Experimental results demonstrate that the proposed rule-based filters have a false positive rate of zero for different attacks.Moreover,the DGAO-IDS model outperforms the comparative models HyDL-IDS and MD-LSTM on the public dataset HCRL.In addition,the model achieves an accuracy of 91.05％on the mixed-attack dataset MixAt,which is 6.55％and 7.93％higher than the HyDL-IDS model and the MD-LSTM model,respectively.
To guarantee the communication security of mobile devices in 5G private networks,the 3rd generation partnership project(3GPP)has proposed the 5G EAP-TLS.However,the existing research work on the 5G EAP-TLS protocol is limited and unsystematic.Therefore,a detailed description of the 5G EAP-TLS protocol and a comprehensive formal modelling of the protocol are provided.All protocol entities involved in the 5G specification are modeled,as well as the certificate distribution mechanism,while the security goals related to the 5G EAP-TLS protocol are extracted and modeled from the 5G specification.A proof search strategy is proposed to guide Tamarin Prover,a symbolic analysis tool,to perform an automated evidence search,thus the problem of Tamarin Prover being unable to terminate the verification process when verifying complex models has been solved,achieving automatic verification of 5G security goals.By analyzing the verification results,it is found that the 5G EAP-TLS protocol can meet confidentiality goals,but it is difficult to meet some authentication goals,revealing that the protocol suffers from denial of service(DoS)attack and has potential threat of user communication data leakage.Finally,a corresponding patch solution is proposed to fix the problems,and the effectiveness of the patch is automatically verified using the Tamarin Prover analysis tool by the proposed proof search strategy.
The unmanned aerial vehicles(UAVs)are applied in lots of scenarios.However,strong mobility,unstable communication links and limited resources make them easy to be attacked.Actually,attacks like denial of service(DoS)attacks,message eavesdropping,global positioning system(GPS)spoofing and false data dissemination cause lots of risks in application.Based on the above attacks,this paper reviewed the flying Ad-Hoc network(FANET)protection schemes in recent years.Firstly,this paper introduced the intrusion detection systems(IDSs),including feature analysis based IDS,signature based IDS and abnormal behavior &.specification based IDS.Then trust management models were described,including the basic trust model,the role based &hierarchical based trust model and other trust models.Finally,the novel protection schemes using artificial intelligence and block-chain technology were introduced.At the end of paper,it listed challenges to improve intrusion detection scheme and trust system,to provide a guidance on F ANET protection.
The open microphone permission required by smart voice assistants brings the risk of user private conversation content leakage.The use of the selective ultrasonic microphone jamming system has been proposed as a means to protect user voice privacy and security.However,the current system is not fully effective in preserving speech privacy,and there are limitations with the active interference cancellation mechanism.Hence,this paper presents a selective ultrasonic microphone jamming system that addresses these challenges by incorporating enhanced safety considerations and improved applicability.This paper employs mixed speech type interference to effectively obfuscate unauthorized devices,enhancing security.Moreover,for improved applicability,an iterative adaptive filtering approach is designed,utilizing a reference high-frequency projection interference copy to enable authorized devices to capture cleaner speech amidst various types of interference signals.Furthermore,this paper extends the selective interference mechanism to preserve the touchless interaction capability between users and voice assistants.Experimental results demonstrate that the proposed system effectively blocks unauthorized microphones,and the quality of the denoised speech is higher than those recovered from existing selective ultrasonic jmicrophone amming systems in terms of subjective and objective speech evaluation.
Bluetooth Mesh is a wireless mesh networking technology.To join a Bluetooth Mesh network,new devices must undergo a provisioning process.The security of the provisioning protocol is the foundation of Bluetooth Mesh network security,but currently there is insufficient research on the security of this protocol,and existing models cannot capture certain attacks that exist in the protocol.Therefore,a formal modeling of the Bluetooth Mesh provisioning protocol is performed using Tamarin Prover,which covers all phases and methods of the provisioning protocol.At the same time,a new method for modeling the AES-CMAC primitive under the symbolic model is proposed with the help of Tamarin Prover's construction and deconstruction rules and the built-in message theory.The method can accurately describe the properties of AES-CMAC functions with arbitrary message lengths,thus enabling a more fine-grained modeling of the authentication phase.The security properties of the model were verified,and the verification results showed that the proposed formal model could capture the previously identified primitive misuse attacks.Furthermore,with the help of this formal model and the verifications results,a countermeasure plan for the primi-tive misuse attack is proposed and verified through the formal approach.
With the rapid development of the mobile Internet and industrial intelligence,the Internet of Vehicles(IoVs)has gradu-ally penetrated into the lives of urban residents.However,while bringing convenience to travel services,security threats have grad-ually been exposed in recent years.These threats include remote malicious control of vehicles,leakage of personal information of vehicle owners,etc.This paper first introduces the typical application scenarios of IoVs,and then investigates the current attack cases in the industry.Secondly,this paper divides the security protection of IoVs into inter-vehicle and intra-vehicle security,ana-lyzes and summarizes the main security threats existing at these two levels.Next,the up-to-date research advance of security pro-tection technologies is introduced.Finally,this paper unlocks the future development direction and research focus of the security protection technology for IoVs.
Most of the current research on Radio Frequency Fingerprint Identification(RFFI)is based on individual's single signal feature,which has the problem of low identification accuracy.To this end,this paper proposes a multi-feature fusion multi-task RF fingerprint identification method,which fuses three signals:power spectrum,time-frequency spectrum based on STFT trans-form,and mutual power spectrum,and uses noise information as a priori knowledge to help network training,with device classifi-cation as the main task and classification of signal noise content as the second task of the network for multi-task learning(MTL).Simulation experiments show that the multi-feature fusion multi-task approach proposed in this paper is improved over the single-feature single-task approach and is an effective method for RF fingerprint identification.
Efficient relay selection methods are beneficial to ensure the timeliness and reliability of safety messages dissemination in urban vehicular networks.However,it is hard for the existing vehicular safety messages relay selection methods to evaluate relays accurately in complex traffic environments,and work well in dense scenarios.Aiming at the above problems,an efficient multi-attribute decision-making and k-means clustering based relay selection method,namely MKRS,was proposed.First,it fully considered four evaluation metrics,including the relative distance and speed between the current forwarding vehicle and candidate relays,the received signal strength and area density of each candidate relay.And it calculated the subjective and objective weights of each relay's evaluation metrics based on order relationship analysis method and entropy weighting method,respectively.Then it used a simple weighting method to obtain corresponding integrated utility values,and comprehensive utility values that can more accurately reflect the performance of candidate relays are further obtained.On this basis,the optimal relay was selected according to a k-means clustering and priority-backoff time based method.The experimental results demonstrate that when compared with the comparative methods,the proposed MKRS has the fastest propagation speed while ensuring good one-hop distance and one-hop delay.
Aiming at the problems of the existing two-tiered wireless sensor network privacy protection range query protocol such as low data security,high communication energy consumption of sensor nodes,and less research for multidimensional data,a two-tiered wireless sensor network privacy protection range query protocol based on cross 0-1 encoding and prime number fusion is pro-posed:in the data submission stage,the sensor nodes collect multi-dimensional data and group according to attribute dimensions,and adopt cross 0-1 encoding,prime number fusion and other methods to optimize the calculation of the comparison factor,and uti-lize AES algorithm to construct the encryption constraint chain to improve data security and reduce computing and communication energy consumption;In the query processing stage,the Sink node uses cross 0-1 encoding and prime number fusion to generate comparison factor for the query range value,and sends the query cell and comparison factor to the storage node as query instruc-tions;the storage node compares the collected data with the comparison factor of the query range value according to the cross 0-1 encoding comparison rule,and completes the multi-dimensional data range query,and sends the results to the Sink node;the Sink node verifies the authenticity and integrity of the query results according to the collection cycle time in the multi-dimensional en-cryption constraint chain and its characteristics.In the experiment,Cortex-M4 and Cortex-A9 kernel development board are used to implement the protocol content,and the functions of data submission,private data query,and authenticity and integrity verifica-tion of private data query results are verified.By comparing the experimental results of the communication energy consumption da-ta between the protocol in this paper and the CSRQ(communication-efficient secure range queries)protocol in the sensor node,it is shown that the communication energy consumption of the new protocol is about 20％lower than that of the CSRQ protocol un-der the same experimental environment.
In the smart grid scenario,the problems of lacking authentication and the ability to verify the secure status of the both ends in the initial computing environment still exist.To fix these problems,this paper proposes a trusted network connection(TNC)scheme based on SM algorithms.Firstly,the scheme realizes the SM algorithms based on FPGA(field programmable gate array)to meet the independent and controllable security requirements.The security of mobile terminals under smart grid is enhanced from the physical level.Secondly,the scheme innovatively applies TNC technology to smart grid mobile terminals,and designs a data security transmission scheme suitable for terminals in smart grid system,which ensures the security of communication links and the legitimacy of terminals.Finally,we implement the prototype system and conduct simulation experiments.The experimental results illustrate the effectiveness of the proposed TNC scheme,and it has a good application prospect in smart power grid.
清洁高效的可再生能源技术是人类社会高质量、可持续发展的一个重要命题.电能存储技术是实现电网稳定与智能化、可再生能源的高效利用以及电气化交通的关键技术;电能与物质之间的转换则是实现"双碳"目标和绿色发展的重要途径.本专辑邀请了国内电能存储与转换技术研究领域的知名青年学者和优秀学子,聚焦该领域研究前沿,撰写相关论文,并从中精选了 14篇论文,从电化学储能、电能-物质转换和新型发电技术三个方面对材料制备、性能、机理、器件方面进行概述和展望.
Mn基钠超离子导体(NASICON)结构材料NaMnM(PO4)3(M=V、Ti、Cr、Zr、Fe等)具有组分、结构、电位可调且成本低等特点,作为钠离子电池正极材料极具应用前景.本文系统总结了 Mn基NASICON结构材料的结构特征和电化学性能,探讨了该类材料存在的关键问题以及改性途径,并提出其作为正极材料未来的研究方向.
将Co基金属有机框架材料(二甲基咪唑钴,ZIF-67)与多巴胺经原位吸附、聚合、碳化、活化,制备高吡啶氮、石墨氮掺杂的中空环形碳(N-doped hollow cycle-like carbon,NHCC),并考察了其氧催化性能.结果表明,最优条件制备的NHCC-0.4 氧还原反应(oxygen reduction reaction,ORR)半波电位 0.782 V;氧析出反应(oxygen evolution reaction,OER)达到 10 mA/cm2的电流密度,过电位为277 mV,低于同载量标准催化剂RuO2(341 mV);同时,其电位差值(0.725 V)低于标准催化剂电对Pt/C||RuO2(0.755 V),表明具备优异的可逆充放电性能.以NHCC-0.4||NHCC-0.4为空气电极的锌-空电池开路电位1.445 V、功率密度138 mW/cm2,可逆充放电循环老化电位差稳定于1.01 V,显著优于标准催化剂Pt/C||RuO2空气电极(1.348 V,108 mW/cm2,1.96 V).其优异的双功能氧催化活性归属为两方面原因:1)高活性吡啶氮与石墨氮催化位点加速了氧还原/氧析出反应动力学过程;2)多孔结构提升了固(活性位点)-液(电解质溶液)-气(氧气)反应相界面形成效率,提高了活性位利用率.
质子交换膜水电解器(proton exchange membrane water electrolyzers,PEMWE)可以实现可再生能源与氢能的高效转化,但其阳极析氧反应(oxygen evolution reaction,OER)过程缓慢,阻碍了其实际应用.铱基、钌基贵金属是目前较为优异的阳极催化剂,但有限的自然储量和高昂的成本限制了其大规模应用.为此,开发高效、稳定且低贵金属含量的催化剂成为当下研究热点之一.本文综述了近年酸性OER催化剂研究进展,首先阐述了吸附质演化机制和晶格氧氧化机制这两种主流OER反应机理,然后从贵金属合金、掺杂氧化物、单原子位点三种结构出发总结了最近报道的低Ir/Ru含量酸性OER催化剂,并围绕反应机制研究、材料结构设计和器件性能评估等角度对其未来发展进行了展望.
以电沉积法在泡沫镍(NF)上原位制备了 MOF材料FexNiy-CA/NF(CA:三聚氰酸),并采用空气煅烧法将Fe1Ni1-CA/NF部分氧化,得到含有NiFe2O4和Fe1Ni1-CA的三维网状多孔镍铁基电催化剂Fe1Ni1O/NF-T,探讨了煅烧温度T对其电催化析氧反应(OER)的影响.研究结果表明,Fe1Ni1O/NF-350的电催化活性最佳,在100mA/cm2的高电流密度下,超电势仅为353 mV;同时具有良好的稳定性,在390 mV高超电势下,Fe1Ni1O/NF-350经过110 h的测试后仅衰减7.66％.
清洁高效的可再生能源技术是人类社会实现可持续、高质量发展的必由之路.电能存储技术是实现电网稳定与智能化、可再生能源的高效利用,以及电气化交通的关键技术.电能与物质之间的转换则是实现"双碳"目标与循环经济的重要途径.因此,基于材料电化学的电能存储与转换技术迎来了前所未有的机遇,在机理、关键材料、性能、器件等方面取得丰硕成果的同时,也面临一些重大挑战.
