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MEC-based architecture for interoperable and trustworthy internet of moving things
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作者 Jesus Sanchez-Gomez Rafael Marin-Perez +1 位作者 Ramon Sanchez-Iborra Miguel Angel Zamora 《Digital Communications and Networks》 SCIE CSCD 2023年第1期270-279,共10页
The expansion of the Internet of Moving Things(IoMT)leads to limitless and continuous working playgrounds exploited by highly dynamic end devices.This requires the adoption of multi-Radio Access Technologies(RATs)-bas... The expansion of the Internet of Moving Things(IoMT)leads to limitless and continuous working playgrounds exploited by highly dynamic end devices.This requires the adoption of multi-Radio Access Technologies(RATs)-based strategies to provide IoMT units with ubiquitous connectivity.To this end,the development of secure bootstrapping and authentication mechanisms is necessary to permit the secure operation of end devices.Given the transmission and power limitations of these elements,current cryptographic solutions do not address these stringent requirements.For that reason,in the study we present a Multi-Access Edge Computing(MEC)-based endto-end architecture that enables an efficient and secure authentication and key agreement between end devices and network servers over heterogeneous resource-limited networks such as the Low Power Wide Area Networks(LPWANs).Our proposal is based on the Authentication,Authorization,and Accounting(AAA)architecture and the recent Internet Engineering Task Force initiatives Static Context Header Compression and Low-Overhead CoAP-EAP.The results obtained from experimental tests reveal the validity of the proposal as it enables constrained IoMT devices to gain IPv6 connectivity as well as performs end-to-end secure authentication with notable reliability and controlled latency. 展开更多
关键词 Internet of moving things LPWAN Authentication LO-CoAP-EAP SCHC
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Optical Properties of Zinc-Blende InGaN/GaN Quantum Well Structures and Comparison with Experiment
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作者 PARK Seoung-Hwan LEE Yong-Tak 《Chinese Physics Letters》 SCIE CAS CSCD 2010年第4期136-139,共4页
Optical properties of zinc-blende InGaN/GaN Q W structures are investigated using the multiband effective-mass theory. The transition wavelength values at 300 K ranged from 440 to 570nm in the investigated range of th... Optical properties of zinc-blende InGaN/GaN Q W structures are investigated using the multiband effective-mass theory. The transition wavelength values at 300 K ranged from 440 to 570nm in the investigated range of the In composition and the well width. The theoretical wavelengths show reasonable agreement with the experimental results. The optical gain decreases with the increasing well width. This is mainly due to the reduction in the quasi-Fermi-level separation because the optical matrix element increases with the well width. 展开更多
关键词 Condensed matter: electrical magnetic and optical Surfaces interfaces and thin films Nanoscale science and low-D systems
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Coupled CUBIC Congestion Control for MPTCP in Broadband Networks
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作者 Jae Yong Lee Byung Chul Kim +1 位作者 Youngmi Kwon Kimoon Han 《Computer Systems Science & Engineering》 SCIE EI 2023年第4期99-115,共17页
Recently,multipath transmission control protocol(MPTCP)was standardized so that data can be transmitted through multiple paths to utilize all available path bandwidths.However,when high-speed long-distance networks ar... Recently,multipath transmission control protocol(MPTCP)was standardized so that data can be transmitted through multiple paths to utilize all available path bandwidths.However,when high-speed long-distance networks are included in MPTCP paths,the traffic transmission performance of MPTCP is severely deteriorated,especially in case the multiple paths’characteristics are heavily asymmetric.In order to alleviate this problem,we propose a“Coupled CUBIC congestion control”that adopts TCP CUBIC on a large bandwidth-delay product(BDP)path in a linked increase manner for maintaining fairness with an ordinary TCP traversing the same bottleneck path.To verify the performance excellence of the proposed algorithm,we implemented the Coupled CUBIC Congestion Control into Linux kernels by modifying the legacy MPTCP linked-increases algorithm(LIA)congestion control source code.We constructed asymmetric heterogeneous network testbeds mixed with large and small BDP paths and compared the performances of LIA and Coupled CUBIC by experiments.Experimental results show that the proposed Coupled CUBIC utilizes almost over 80%of the bandwidth resource in the high BDP path,while the LIA utilizes only less than 20%of the bandwidth for the same path.It was confirmed that the resource utilization and traffic transmission performance have been greatly improved by using the proposed Coupled CUBIC in high-speed multipath networks,as well as maintaining MPTCP fairness with competing single-path CUBIC or Reno TCP flows. 展开更多
关键词 MPTCP congestion control Coupled CUBIC high BDP network
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Construction of protograph LDPC codes with circular generator matrices 被引量:5
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作者 Kaiyao Wang Yang Xiao Kiseon Kim 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2011年第5期840-847,共8页
The application of protograph low density parity check (LDPC) codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder nee... The application of protograph low density parity check (LDPC) codes involves the encoding complexity problem. Since the generator matrices are dense, and if the positions of "1" s are irregularity, the encoder needs to store every "1" of the generator matrices by using huge chip area. In order to solve this problem, we need to design the protograph LDPC codes with circular generator matrices. A theorem concerning the circulating property of generator matrices of nonsingular protograph LDPC codes is proposed. The circulating property of generator matrix of nonsingular protograph LDPC codes can be obtained from the corresponding quasi-cyclic parity check matrix. This paper gives a scheme of constructing protograph LDPC codes with circulating generator matrices, and it reveals that the fast encoding algorithm of protograph LDPC codes has lower encoding complexity under the condition of the proposed theorem. Simulation results in ad- ditive white Gaussian noise (AWGN) channels show that the bit error rate (BER) performance of the designed codes based on the proposed theorem is much better than that of GB20600 LDPC codes and Tanner LDPC codes. 展开更多
关键词 protograph low density parity check (LDPC) codes cyclic matrices fast encoding algorithm bit error rate (BER) performance.
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Joint Dynamic Clustering and User Scheduling for Downlink Cloud Radio Access Network with Limited Feedback 被引量:2
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作者 XU Dongyang REN Pinyi +1 位作者 DU Qinghe SUN Li 《China Communications》 SCIE CSCD 2015年第12期147-159,共13页
In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral efficiency.We,in this paper,prop... In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral efficiency.We,in this paper,propose an efficient three-phase framework and corresponding algorithms for dealing with this problem.Firstly,a greedy scheduling algorithm based on the lower bound of the ergodic rate is performed for generating an elementary cluster in the first phase.And then the elementary cluster is divided into many small clusters according to the following proposed algorithms based on the short term instantaneous information in the second phase.In the end,based on the limited feedback two zero-forcing(ZF) precoding strategies are adopted for reducing the intra-cluster interference in the third phase.The provided Monte Carlo simulations show the effectiveness of our proposed algorithms in the respect of system spectral efficiency and average user rate. 展开更多
关键词 调度算法 无线接入网 动态聚类 反馈 用户 节点 蒙特卡罗模拟 频谱效率
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Diffserv AQM algorithm for edge and core routers 被引量:2
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作者 Yang Xiao Lingyun Lu Kiseon Kim 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第6期1033-1040,共8页
The existing active queue management (AQM) algorithm acts on subscribers and edge routers only, it does not support differentiate-serve (Diffserv) quality of service (QoS), while the existing diffserv QoS has no... The existing active queue management (AQM) algorithm acts on subscribers and edge routers only, it does not support differentiate-serve (Diffserv) quality of service (QoS), while the existing diffserv QoS has not considered the link capacities between edge routers and connected core routers. When a core router in a two layers’ network experiences congestion, the connected edge routers have no ability to adjust their access data rates. Thus, it is difficult to achieve the congestion control for the large scale network with many edge routers and core routers. To solve these problems, two difffserve AQM algorithms are proposed for the congestion control of multilayer network. One diffserv AQM algorithm implements fair link capacities of edge routers, and the other one implements unequal link capacities of edge routers, but it requires the core routers to have multi-queues buffers and Diffserv AQM to support. The proposed algorithms achieve the network congestion control by operating AQM parameters on the conditions of proposed three theorems for core and edge routers. The dynamic simulation results demonstrate the proposed control algorithms for core and edge routers to be valid. 展开更多
关键词 active queue management (AQM) core router control multilayer network.
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A Novel Soft Sensor Modeling Approach Based on Least Squares Support Vector Machines 被引量:1
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作者 冯瑞 Song Chunlin +1 位作者 Zhang Yanzhu Shao Huihe 《High Technology Letters》 EI CAS 2004年第4期39-42,共4页
Artificial Neural Networks (ANNs) such as radial basis function neural networks (RBFNNs) have been successfully used in soft sensor modeling. However, the generalization ability of conventional ANNs is not very well. ... Artificial Neural Networks (ANNs) such as radial basis function neural networks (RBFNNs) have been successfully used in soft sensor modeling. However, the generalization ability of conventional ANNs is not very well. For this reason, we present a novel soft sensor modeling approach based on Support Vector Machines (SVMs). Since standard SVMs have the limitation of speed and size in training large data set, we hereby propose Least Squares Support Vector Machines (LS_SVMs) and apply it to soft sensor modeling. Systematic analysis is performed and the result indicates that the proposed method provides satisfactory performance with excellent approximation and generalization property. Monte Carlo simulations show that our soft sensor modeling approach achieves performance superior to the conventional method based on RBFNNs. 展开更多
关键词 支持向量机 传感器 人工神经网络 RBF
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MCHOKeM algorithm with assured bandwidth allocation in DiffServ networks
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作者 Haifeng Du Yang Xiao Kiseon Kim 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2010年第4期531-536,共6页
An active queue management(AQM) algorithm called MCHOKeM is presented,which is borrowed from CHOKeW that draws multi-packets at random from the buffer,the multi-packets are compared with an arriving packet and aband... An active queue management(AQM) algorithm called MCHOKeM is presented,which is borrowed from CHOKeW that draws multi-packets at random from the buffer,the multi-packets are compared with an arriving packet and abandoned if they are from the same flow.But MCHOKeM uses multiple virtual queues for different priority packets and enhances the drawing function by adjusting the maximum number of draws based on the current status of virtual queue length.The number of parameters that MCHOKeM needs to maintain is determined by the number of priority levels being supported by the router,which usually has a small limited value.In order to explain the features of MCHOKeM,an analytical model is used.A series of simulation tests to evaluate the performance are given. 展开更多
关键词 congestion control theory differentiated services(DiffServ) transaction control protocol(TCP) protection fairness analysis.
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Economic Feasibility Assessment of Motorized PV Louver System Considering the Near Shading Parameter, Array Incidence Losses and Other Environmental Factors
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作者 Hussein Safwat Hasan Humor Hwang 《World Journal of Engineering and Technology》 2024年第3期540-551,共12页
Seoul has good weather settings for incorporating renewable energies, hence, given its small land area living mode was mostly set in an apartment condition it is an ideal place for building applied photovoltaic (BAPV)... Seoul has good weather settings for incorporating renewable energies, hence, given its small land area living mode was mostly set in an apartment condition it is an ideal place for building applied photovoltaic (BAPV) for solar energy harvesting. On the other hand, the BAPV energy self-consumption hasn’t been thoroughly examined considering the overall energy consumption requirement. Therefore, presented in this communication are the viability of PVL to produce electricity from solar energy and insights on modulating and improving energy harvesting efficiency. To accomplish this objective, three major factors were considered: 1) the photovoltaic (PV) positioning;2) the solar tracking scenario;and 3) the mechanistic system energy consumption. The overall louver energy generation was thoroughly scrutinized from the net energy conception of the BAPV up to the mechanistic module energy expenditure. This work intends to provide insights into the economic feasibility of BAPV assessing its technological profitability in the specified location and building size. 展开更多
关键词 Photovoltaic Louvers Energy Consumption Tracking System Building Integrated Photovoltaic PVsyst
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Performance Assessment of Motorized Solar Photovoltaic Louvers System Using PVSYST Software
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作者 Hussein Safwat Hasan Hasan Humor Hwang 《Electrical Science & Engineering》 2021年第2期30-39,共10页
In the realm of technological market penetration of solar photovoltaic louvers(PVL)addressing environmental difficulties and the industrial revolution,a new avenue of renewable energy is introduced.Moreover,solar ener... In the realm of technological market penetration of solar photovoltaic louvers(PVL)addressing environmental difficulties and the industrial revolution,a new avenue of renewable energy is introduced.Moreover,solar energy exploitation through building façades was addressed through motorized solar photovoltaic louvers(MPVL).On the other hand,proponents exalted the benefits of MPVL overlooking the typical analyses.In this communication,we attempted to perform a thorough industrial system evaluation of the MPVL.This communication presents a methodology to validate the industrial claims about MPVL devices and their economic efficiency and the insight on how geographical location influences their utilization and augment their potential benefits.This task is carried out by evaluating the extent of solar energy that can be harvested using solar photovoltaic system(PVSYST)software and investigating whether existing product claims are associated with MPVL are feasible in different locations.The performance and operational losses(temperature,internal network,power electronics)were evaluated.To design and assess the performance of different configurations based on the geographical analogy,simulation tools were successfully carried out based on different topographical locations.Based on these findings,various factors affect the employment of MPVL such as geographical and weather conditions,solar irradiation,and installation efficiency.tt is assumed that we successfully shed light and provided insights into the complexity associated with MPVL. 展开更多
关键词 Motorized solar photovoltaic louvers(MPVL) Photovoltaic(PV) PVsyst software Direct solar radiation Parametric louver design
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Research on Federated Learning Data Sharing Scheme Based on Differential Privacy
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作者 Lihong Guo 《Computers, Materials & Continua》 SCIE EI 2023年第3期5069-5085,共17页
To realize data sharing,and to fully use the data value,breaking the data island between institutions to realize data collaboration has become a new sharing mode.This paper proposed a distributed data security sharing... To realize data sharing,and to fully use the data value,breaking the data island between institutions to realize data collaboration has become a new sharing mode.This paper proposed a distributed data security sharing scheme based on C/S communication mode,and constructed a federated learning architecture that uses differential privacy technology to protect training parameters.Clients do not need to share local data,and they only need to upload the trained model parameters to achieve data sharing.In the process of training,a distributed parameter update mechanism is introduced.The server is mainly responsible for issuing training commands and parameters,and aggregating the local model parameters uploaded by the clients.The client mainly uses the stochastic gradient descent algorithm for gradient trimming,updates,and transmits the trained model parameters back to the server after differential processing.To test the performance of the scheme,in the application scenario where many medical institutions jointly train the disease detection system,the model is tested from multiple perspectives by taking medical data as an example.From the testing results,we can know that for this specific test dataset,when the parameters are properly configured,the lowest prediction accuracy rate is 90.261%and the highest accuracy rate is up to 94.352.It shows that the performance of the model is good.The results also show that this scheme realizes data sharing while protecting data privacy,completes accurate prediction of diseases,and has a good effect. 展开更多
关键词 Federated learning C/S mode differential privacy gradient descent prediction accuracy
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A Lightweight ABE Security Protection Scheme in Cloud Environment Based on Attribute Weight
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作者 Lihong Guo Jie Yang Haitao Wu 《Computers, Materials & Continua》 SCIE EI 2023年第8期1929-1946,共18页
Attribute-based encryption(ABE)is a technique used to encrypt data,it has the flexibility of access control,high security,and resistance to collusion attacks,and especially it is used in cloud security protection.Howe... Attribute-based encryption(ABE)is a technique used to encrypt data,it has the flexibility of access control,high security,and resistance to collusion attacks,and especially it is used in cloud security protection.However,a large number of bilinear mappings are used in ABE,and the calculation of bilinear pairing is time-consuming.So there is the problem of low efficiency.On the other hand,the decryption key is not uniquely associated with personal identification information,if the decryption key is maliciously sold,ABE is unable to achieve accountability for the user.In practical applications,shared message requires hierarchical sharing in most cases,in this paper,we present a message security hierarchy ABE scheme for this scenario.Firstly,attributes were grouped and weighted according to the importance of attributes,and then an access structure based on a threshold tree was constructed according to attribute weight.This method saved the computing time for decryption while ensuring security and on-demand access to information for users.In addition,with the help of computing power in the cloud,two-step decryption was used to complete the access,which relieved the computing and storage burden on the client side.Finally,we simulated and tested the scheme based on CP-ABE,and selected different security levels to test its performance.The security proof and the experimental simulation result showthat the proposed scheme has high efficiency and good performance,and the solution implements hierarchical access to the shared message. 展开更多
关键词 Attribute-based encryption cloud security message hierarchy attribute weight access control
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Building an interoperable space for smart agriculture
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作者 Ioanna Roussaki Kevin Doolin +5 位作者 Antonio Skarmeta George Routis Juan Antonio Lopez-Morales Ethel Claffey Manuel Mora Juan Antonio Martinez 《Digital Communications and Networks》 SCIE CSCD 2023年第1期183-193,共11页
The digital transformation in agriculture introduces new challenges in terms of data,knowledge and technology adoption due to critical interoperability issues,and also challenges regarding the identification of the mo... The digital transformation in agriculture introduces new challenges in terms of data,knowledge and technology adoption due to critical interoperability issues,and also challenges regarding the identification of the most suitable data sources to be exploited and the information models that must be used.DEMETER(Building an Interoperable,Data-Driven,Innovative and Sustainable European Agri-Food Sector)addresses these challenges by providing an overarching solution that integrates various heterogeneous hardware and software resources(e.g.,devices,networks,platforms)and enables the seamless sharing of data and knowledge throughout the agri-food chain.This paper introduces the main concepts of DEMETER and its reference architecture to address the data sharing and interoperability needs of farmers,which is validated via two rounds of 20 large-scale pilots along the DEMETER lifecycle.This paper elaborates on the two pilots carried out in region of Murcia in Spain,which target the arable crops sector and demonstrate the benefits of the deployed DEMETER reference architecture. 展开更多
关键词 Smart agriculture Internet of things(IoT) DEMETER Reference architecture INTEROPERABILITY Agricultural information model(AIM) Pilot validation
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Unmanned Aerial Vehicle Multi-Access Edge Computing as Security Enabler for Next-Gen 5G Security Frameworks
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作者 Jaime Ortiz Córdoba Alejandro Molina Zarca Antonio Skármeta 《Intelligent Automation & Soft Computing》 SCIE 2023年第8期2307-2333,共27页
5G/Beyond 5G(B5G)networks provide connectivity to many heterogeneous devices,raising significant security and operational issues and making traditional infrastructure management increasingly complex.In this regard,new... 5G/Beyond 5G(B5G)networks provide connectivity to many heterogeneous devices,raising significant security and operational issues and making traditional infrastructure management increasingly complex.In this regard,new frameworks such as Anastacia-H2020 or INSPIRE-5GPlus automate the management of next-generation infrastructures,especially regarding policy-based security,abstraction,flexibility,and extensibility.This paper presents the design,workflow,and implementation of a security solution based on Unmanned Aerial Vehicles(UAVs),able to extend 5G/B5G security framework capabilities with UAV features like dynamic service provisioning in specific geographic areas.The proposed solution allows enforcing UAV security policies in proactive and reactive ways to automate UAV dynamic deployments and provisioning security Virtual Network Functions(VNFs)in the onboard Multi-access Edge Computing(MEC)node.A UAV has been ensembled from scratch to validate the proposal,and a raspberry-pi has been onboarded as compute node.The implementation provides a VNF for dynamic UAV management,capable of dynamically loading waypoints into the flight controller to address reactive autonomous flights,and anMLbased VNF capable of detecting image patterns.According to the security policies,the onboard VNFs can be dynamically configured to generate alerts to the framework and apply local reactions depending on the detection made.In our experiments,we measured the time it takes for the solution to be ready after receiving a security policy for detecting patterns in a specific geographical area.The time it takes for the solution to react automatically was also measured.The results show that the proactive flow configuration considering ten waypoints can be enforced in less than 3 s,and a local reactive flow can be enforced in around 1 s.We consider that the results are promising and aligned with other security enabler solutions as part of existing 5G/6G security frameworks. 展开更多
关键词 UAV 5G AI NFV SECURITY
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Federated Network Intelligence Orchestration for Scalable and Automated FL-Based Anomaly Detection in B5G Networks
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作者 Pablo Fernández Saura José M.Bernabé Murcia +3 位作者 Emilio García de la Calera Molina Alejandro Molina Zarca Jorge Bernal Bernabé Antonio F.Skarmeta Gómez 《Computers, Materials & Continua》 SCIE EI 2024年第7期163-193,共31页
The management of network intelligence in Beyond 5G(B5G)networks encompasses the complex challenges of scalability,dynamicity,interoperability,privacy,and security.These are essential steps towards achieving the reali... The management of network intelligence in Beyond 5G(B5G)networks encompasses the complex challenges of scalability,dynamicity,interoperability,privacy,and security.These are essential steps towards achieving the realization of truly ubiquitous Artificial Intelligence(AI)-based analytics,empowering seamless integration across the entire Continuum(Edge,Fog,Core,Cloud).This paper introduces a Federated Network Intelligence Orchestration approach aimed at scalable and automated Federated Learning(FL)-based anomaly detection in B5Gnetworks.By leveraging a horizontal Federated learning approach based on the FedAvg aggregation algorithm,which employs a deep autoencoder model trained on non-anomalous traffic samples to recognize normal behavior,the systemorchestrates network intelligence to detect and prevent cyber-attacks.Integrated into a B5G Zero-touch Service Management(ZSM)aligned Security Framework,the proposal utilizes multi-domain and multi-tenant orchestration to automate and scale the deployment of FL-agents and AI-based anomaly detectors,enhancing reaction capabilities against cyber-attacks.The proposed FL architecture can be dynamically deployed across the B5G Continuum,utilizing a hierarchy of Network Intelligence orchestrators for real-time anomaly and security threat handling.Implementation includes FL enforcement operations for interoperability and extensibility,enabling dynamic deployment,configuration,and reconfiguration on demand.Performance validation of the proposed solution was conducted through dynamic orchestration,FL,and real-time anomaly detection processes using a practical test environment.Analysis of key performance metrics,leveraging the 5G-NIDD dataset,demonstrates the system’s capability for automatic and near real-time handling of anomalies and attacks,including real-time network monitoring and countermeasure implementation for mitigation. 展开更多
关键词 Federated learning 6G orchestration anomaly detection security policy
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Physical Layer Security with Its Applications in 5GNetworks: A Review 被引量:7
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作者 Li Sun Qinghe Du 《China Communications》 SCIE CSCD 2017年第12期1-14,共14页
5G network is expected to support massive user connections and exponentially increasing wireless services,which makes network security unprecedentedly important.Unlike traditional security-guaranteeing techniques whic... 5G network is expected to support massive user connections and exponentially increasing wireless services,which makes network security unprecedentedly important.Unlike traditional security-guaranteeing techniques which rely heavily on cryptographic approaches at upper layers of the protocol stack,physical-layer security(PLS) solutions fully take advantages of the characteristics of wireless channels to degrade the received signal qualities at the malicious users,and realize keyless secure transmission via signal design and signal processing techniques.PLS avoids the difficulties in the distribution and management of secret keys,and provides flexible security levels through adaptive transmission protocol design.Moreover,PLS techniques match the features of 5G networks well.Therefore,the application of PLS to 5G networks is a promising solution to address the security threats.This article presents a comprehensive review of the state-of-the-art PLS techniques,and discusses their applications in 5G networks.We first summarize the principle and advantages of PLS techniques,and point out the reasons why PLS is suitable for 5G networks.Then,we review the existing PLS methods in literature,and highlight severalPLS solutions that are expected to be applied in 5G networks.Finally,we conclude this article and figure out some further research directions. 展开更多
关键词 5G PHYSICAL layer security an-ti-eavesdropping signal design STATISTICAL se-curity GUARANTEE FOUNTAIN CODING
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Semi-Supervised Learning Based Big Data-Driven Anomaly Detection in Mobile Wireless Networks 被引量:6
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作者 bilal hussain qinghe du pinyi ren 《China Communications》 SCIE CSCD 2018年第4期41-57,共17页
With rising capacity demand in mobile networks, the infrastructure is also becoming increasingly denser and complex. This results in collection of larger amount of raw data(big data) that is generated at different lev... With rising capacity demand in mobile networks, the infrastructure is also becoming increasingly denser and complex. This results in collection of larger amount of raw data(big data) that is generated at different levels of network architecture and is typically underutilized. To unleash its full value, innovative machine learning algorithms need to be utilized in order to extract valuable insights which can be used for improving the overall network's performance. Additionally, a major challenge for network operators is to cope up with increasing number of complete(or partial) cell outages and to simultaneously reduce operational expenditure. This paper contributes towards the aforementioned problems by exploiting big data generated from the core network of 4 G LTE-A to detect network's anomalous behavior. We present a semi-supervised statistical-based anomaly detection technique to identify in time: first, unusually low user activity region depicting sleeping cell, which is a special case of cell outage; and second, unusually high user traffic area corresponding to a situation where special action such as additional resource allocation, fault avoidance solution etc. may be needed. Achieved results demonstrate that the proposed method can be used for timely and reliable anomaly detection in current and future cellular networks. 展开更多
关键词 机器学习算法 无线网络 数据驱动 监督 活动网络 基础结构 TIAL 核心网络
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Network-adaptive HD MPEG-2 video streaming with cross-layered channel monitoring in WLAN
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作者 PARK Sanghoon YOON Hayoung KIM Jongwon 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第5期885-893,共9页
In this paper, we propose a practical design and implementation of network-adaptive high definition (HD) MPEG-2 video streaming combined with cross-layered channel monitoring (CLM) over the IEEE 802.11a wireless local... In this paper, we propose a practical design and implementation of network-adaptive high definition (HD) MPEG-2 video streaming combined with cross-layered channel monitoring (CLM) over the IEEE 802.11a wireless local area network (WLAN). For wireless channel monitoring, we adopt a cross-layered approach, where an access point (AP) periodically measures lower layers such as medium access control (MAC) and physical (PHY) transmission information (e.g., MAC layer loss rate) and then sends the monitored information to the streaming server application. The adaptive streaming server with the CLM scheme reacts more quickly and efficiently to the fluctuating wireless channel than the end-to-end application-layer monitoring (E2EM) scheme. The streaming server dynamically performs priority-based frame dropping to adjust the sending rate according to the measured wireless channel condition. For this purpose, the proposed streaming system nicely provides frame-based prioritized packetization by using a real-time stream parsing module. Various evaluation results over an IEEE 802.11a WLAN testbed are provided to verify the intended Quality of Service (QoS) adaptation capability. Experimental results showed that the proposed system can mitigate the quality degradation of video streaming due to the fluctuations of time-varying channel. 展开更多
关键词 Wireless video ADAPTIVE VIDEO streaming Cross-layered design Prioritized packetization MPEG-2
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Efficient nonlinear companding scheme for substantial reduction in peak-to-average power ratio of OFDM
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作者 Kasun Bandara Atul Sewaiwar Yeon-Ho Chung 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2015年第5期924-931,共8页
Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear comp... Orthogonal frequency division multiplexing(OFDM)produces a high peak-to-average power ratio(PAPR) that adversely affects high-speed OFDM data transmission. In order to reduce the high PAPR, an efficient nonlinear companding transform(NCT) function is proposed. With the proposed NCT function,the compression and expansion weights can be applied independently with suitably chosen function parameter values. As a result, the proposed function can easily maintain the average signal power approximately unchanged during the companding process.In this regard, the proposed function is superior to previously proposed schemes. Also, the simulations show the outstanding PAPR reduction performance of the proposed function. It is demonstrated that the proposed scheme performs well with nonlinear transmitter amplifiers and delivers superior error performance, compared with error function and exponential function based schemes. 展开更多
关键词 峰值平均功率比 OFDM 非线性 压扩 PAPR 正交频分复用 压缩过程 指数函数
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Motion Enhanced Model Based on High-Level Spatial Features
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作者 Yang Wu Lei Guo +3 位作者 Xiaodong Dai Bin Zhang Dong-Won Park Ming Ma 《Computers, Materials & Continua》 SCIE EI 2022年第12期5911-5924,共14页
Action recognition has become a current research hotspot in computer vision.Compared to other deep learning methods,Two-stream convolutional network structure achieves better performance in action recognition,which di... Action recognition has become a current research hotspot in computer vision.Compared to other deep learning methods,Two-stream convolutional network structure achieves better performance in action recognition,which divides the network into spatial and temporal streams,using video frame images as well as dense optical streams in the network,respectively,to obtain the category labels.However,the two-stream network has some drawbacks,i.e.,using dense optical flow as the input of the temporal stream,which is computationally expensive and extremely time-consuming for the current extraction algorithm and cannot meet the requirements of real-time tasks.In this paper,instead of the dense optical flow,the Motion Vectors(MVs)are used and extracted from the compressed domain as temporal features,which greatly reduces the extraction time.However,the motion pattern that MVs contain is coarser,which leads to low accuracy.In this paper,we propose two strategies to improve the accuracy:firstly,an accumulated strategy is used to enhance the motion information and continuity of MVs;secondly,knowledge distillation is used to fuse the spatial information into the temporal stream so that more information(e.g.,motion details,colors,etc.)is obtainable.Experimental results show that the accuracy of MV can be greatly improved by the strategies proposed in this paper and the final recognition for human actions accuracy is guaranteed without using optical flow. 展开更多
关键词 Action recognition motion vectors two-stream knowledge distillation accumulate strategy
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