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Chemical, Nutritional and Organoleptical Characteristics of Orange-Based Formulated Low-Calorie Jams 被引量:1
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作者 Rafeek M. Abolila Hassan Barakat +1 位作者 Hassan A. El-Tanahy Hamdy A. El-Mansy 《Food and Nutrition Sciences》 2015年第13期1229-1244,共16页
Twelve low-calorie orange-based formulated jams were prepared mainly from orange, pumpkin and papaya, and then sweetened using fructose (F), stevioside (St) and sucralose (Su). The nutritional value of formulated jams... Twelve low-calorie orange-based formulated jams were prepared mainly from orange, pumpkin and papaya, and then sweetened using fructose (F), stevioside (St) and sucralose (Su). The nutritional value of formulated jams was estimated after the approximate chemical composition and total soluble solid have been determined. The effect of storage on total phenolic compounds, antioxidant capacity, carotenoids content and vitamin C was investigated. Organoleptical attributes of prepared low-calorie jams were done as well. Results indicated that the nutritive value [kcal 100 g–1 fw] ranged from 88.10 ± 0.60 to 164.34 ± 0.41;total phenol content (TPC, mg GAE 100 g–1 fw] ranged from 188.52 ± 2.45 to 411.79 ± 3.3;the antioxidant capacity (μmol TE g–1 fw) ranged from 14.57 ± 0.86 to 32.39 ± 1.19;total carotenoids [mg 100 g–1 fw] ranged from 115.20 ± 5.66 to 204.33 ± 4.21;vitamin C [mg 100 g fw] ranged from 8.94 ± 1.07 to 28.77 ± 4.46;total soluble solids [Brix] ranged from 22.53 ± 0.05 to 43.37 ± 0.13. Jams storage for a period of 12 months at room temperature led to a decrease in vitamin C content, TPC, antioxidant capacity, while total soluble solids (TSS) and carotenoids increased during storage. The results of organoleptical attributes showed that the formulas O11, O1 had the highest score of color and odor respectively while O7 recorded maximum score for taste, texture and bitterness respectively. Statistical analysis showed that storage intervals and treatments had a significant (p < 0.05) effect on sensory quality of diet jam. The organoleptical characteristics were affected with the extension of shelf-life. Addition of stevioside and sucralose to formulate the low-calorie jam increased total phenol and antioxidant capacity, improved color, taste and produced targeted low-calorie jams. The use of sweeteners such as fructose, sucralose and stevioside in the manufacture of orange diet jam was shown to be satisfactory, resulting in low-calorie jams, improved the quality and could be produced commercially. 展开更多
关键词 low-calorie jam CHEMICAL NUTRITIONAL Organoleptical CHARACTERISTICS
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基于Jamming转变理论的沥青路面车辙演化机制
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作者 赵晓康 张凯 +2 位作者 裴建中 张久鹏 计杰 《哈尔滨工业大学学报》 EI CAS CSCD 北大核心 2024年第9期150-160,共11页
沥青路面宏观车辙其实质是混合料细观结构演变的结果,为了深入理解路面车辙流变行为的发展过程,基于颗粒物质Jamming理论开展了沥青混合料车辙演化机制研究。采用图像处理技术构建了沥青混合料细观结构模型,基于时-温等效原理开展了车... 沥青路面宏观车辙其实质是混合料细观结构演变的结果,为了深入理解路面车辙流变行为的发展过程,基于颗粒物质Jamming理论开展了沥青混合料车辙演化机制研究。采用图像处理技术构建了沥青混合料细观结构模型,基于时-温等效原理开展了车辙仿真测试,分析了车辙变形过程中混合料宏细观结构的变化特征,探究了沥青路面Unjamming转变行为的影响规律与车辙演化机制。结果表明:Jamming理论可以很好地解释沥青路面的车辙演变全过程,车辙深度与沥青混合料颗粒的堵塞程度密切相关;随着加载时间和作用荷载的增加,混合料Jamming堵塞程度增大,车辙深度和面积分数也逐渐增加,并最终趋于稳定,颗粒体系Jammed态的转变受到了沥青砂浆和集料骨架共同作用的影响;随着测试温度升高,试件内部颗粒位移和位移差增大,混合料Jamming堵塞程度降低。沥青路面颗粒体系由稳定的Jammed态转变为不稳定的Unjammed态,是诱导路面车辙和泛油病害发生的内因,研究结果实现了Jamming理论在非晶体系中的应用,为深入理解沥青混合料的车辙演变行为提供了一种新的研究思路。 展开更多
关键词 道路工程 车辙演化 颗粒体系 jamming转变 细观结构
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A target parameter estimation method via atom-reconstruction in radar mainlobe jamming
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作者 ZHOU Bilei LIU Weijian +5 位作者 LI Rongfeng CHEN Hui ZHANG Liang DU Qinglei LI Binbin CHEN Hao 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期350-360,共11页
Mainlobe jamming(MLJ)brings a big challenge for radar target detection,tracking,and identification.The suppression of MLJ is a hard task and an open problem in the electronic counter-counter measures(ECCM)field.Target... Mainlobe jamming(MLJ)brings a big challenge for radar target detection,tracking,and identification.The suppression of MLJ is a hard task and an open problem in the electronic counter-counter measures(ECCM)field.Target parameters and target direction estimation is difficult in radar MLJ.A target parameter estimation method via atom-reconstruction in radar MLJ is proposed in this paper.The proposed method can suppress the MLJ and simultaneously provide high estimation accuracy of target range and angle.Precisely,the eigen-projection matrix processing(EMP)algorithm is adopted to suppress the MLJ,and the target range is estimated effectively through the beamforming and pulse compression.Then the target angle can be effectively estimated by the atom-reconstruction method.Without any prior knowledge,the MLJ can be canceled,and the angle estimation accuracy is well preserved.Furthermore,the proposed method does not have strict requirement for radar array construction,and it can be applied for linear array and planar array.Moreover,the proposed method can effectively estimate the target azimuth and elevation simultaneously when the target azimuth(or elevation)equals to the jamming azimuth(or elevation),because the MLJ is suppressed in spatial plane dimension. 展开更多
关键词 mainlobe jamming ANTI-jamMING atom-reconstruction RADAR
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Jamming Assisted Covert Wireless Communication in Multi-Channel Systems
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作者 Che Bohan Sha Nan +2 位作者 Yang Weiwei Lu Xingbo Gao Chang 《China Communications》 SCIE CSCD 2024年第9期211-224,共14页
This paper investigates the jammerassisted multi-channel covert wireless communication(CWC)by exploiting the randomness of sub-channel selection to confuse the warden.In particular,we propose two sub-channel selection... This paper investigates the jammerassisted multi-channel covert wireless communication(CWC)by exploiting the randomness of sub-channel selection to confuse the warden.In particular,we propose two sub-channel selection transmission schemes,named random sub-channel selection(RSS)scheme and maximum sub-channel selection(MSS)scheme,to enhance communication covertness.For each proposed scheme,we first derive closed-form expressions of the transmission outage probability(TOP),the average effective rate,and the minimum average detection error probability(DEP).Then,the average effective covert rate(ECR)is maximized by jointly optimizing the transmit power at the transmitter and the number of sub-channels.Numerical results show that there is an optimal value of the number of sub-channels that maximizes the average ECR.We also find that to achieve the maximum average ECR,a larger number of subchannels are needed facing a stricter covertness constraint. 展开更多
关键词 covert wireless communication jamming multi-channel system
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An angular blinking jamming method based on electronically controlled corner reflectors
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作者 GAN Lin WU Zehao +1 位作者 WANG Xuesong LI Jianbing 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第2期330-338,共9页
Passive jamming is believed to have very good potential in countermeasure community.In this paper,a passive angular blinking jamming method based on electronically controlled corner reflectors is proposed.The amplitud... Passive jamming is believed to have very good potential in countermeasure community.In this paper,a passive angular blinking jamming method based on electronically controlled corner reflectors is proposed.The amplitude of the incident wave can be modulated by switching the corner reflector between the penetration state and the reflection state,and the ensemble of multiple corner reflectors with towing rope can result in complex angle decoying effects.Dependency of the decoying effect on corner reflectors’radar cross section and positions are analyzed and simulated.Results show that the angle measured by a monopulse radar can be significantly interfered by this method while the automatic tracking is employed. 展开更多
关键词 monopulse radar angular blinking jamming corner reflector amplitude-comparison angle measurement metasurface
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Optimization of jamming formation of USV offboard active decoy clusters based on an improved PSO algorithm
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作者 Zhaodong Wu Yasong Luo Shengliang Hu 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第2期529-540,共12页
Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for t... Offboard active decoys(OADs)can effectively jam monopulse radars.However,for missiles approaching from a particular direction and distance,the OAD should be placed at a specific location,posing high requirements for timing and deployment.To improve the response speed and jamming effect,a cluster of OADs based on an unmanned surface vehicle(USV)is proposed.The formation of the cluster determines the effectiveness of jamming.First,based on the mechanism of OAD jamming,critical conditions are identified,and a method for assessing the jamming effect is proposed.Then,for the optimization of the cluster formation,a mathematical model is built,and a multi-tribe adaptive particle swarm optimization algorithm based on mutation strategy and Metropolis criterion(3M-APSO)is designed.Finally,the formation optimization problem is solved and analyzed using the 3M-APSO algorithm under specific scenarios.The results show that the improved algorithm has a faster convergence rate and superior performance as compared to the standard Adaptive-PSO algorithm.Compared with a single OAD,the optimal formation of USV-OAD cluster effectively fills the blind area and maximizes the use of jamming resources. 展开更多
关键词 Electronic countermeasure Offboard active decoy USV cluster jamming formation optimization Improved PSO algorithm
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Intelligent recognition and information extraction of radar complex jamming based on time-frequency features
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作者 PENG Ruihui WU Xingrui +3 位作者 WANG Guohong SUN Dianxing YANG Zhong LI Hongwen 《Journal of Systems Engineering and Electronics》 SCIE CSCD 2024年第5期1148-1166,共19页
In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise p... In modern war,radar countermeasure is becoming increasingly fierce,and the enemy jamming time and pattern are changing more randomly.It is challenging for the radar to efficiently identify jamming and obtain precise parameter information,particularly in low signal-to-noise ratio(SNR)situations.In this paper,an approach to intelligent recognition and complex jamming parameter estimate based on joint time-frequency distribution features is proposed to address this challenging issue.Firstly,a joint algorithm based on YOLOv5 convolutional neural networks(CNNs)is proposed,which is used to achieve the jamming signal classification and preliminary parameter estimation.Furthermore,an accurate jamming key parameters estimation algorithm is constructed by comprehensively utilizing chi-square statistical test,feature region search,position regression,spectrum interpolation,etc.,which realizes the accurate estimation of jamming carrier frequency,relative delay,Doppler frequency shift,and other parameters.Finally,the approach has improved performance for complex jamming recognition and parameter estimation under low SNR,and the recognition rate can reach 98%under−15 dB SNR,according to simulation and real data verification results. 展开更多
关键词 complex jamming recognition time frequency feature convolutional neural network(CNN) parameter estimation
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The Impact of Jams on the Vending Robot
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作者 Bourama Coulibaly Drissa Traore +1 位作者 Bakary Dit Dembo Sylla Marie Bernard Sidibe 《Open Journal of Applied Sciences》 2024年第9期2515-2518,共4页
This study aims to identify the causes of sensor jams and its impact on the operation of vending machines. The vending machine is a machine that automatically dispenses products such as drinks, tickets, sandwiches and... This study aims to identify the causes of sensor jams and its impact on the operation of vending machines. The vending machine is a machine that automatically dispenses products such as drinks, tickets, sandwiches and biscuits, by inserting change or credit card into the machine. This technological feat is due to the advent of sensors. A sensor is a part of the measurement chain, it receives the quantity to be measured and provides information directly linked to this quantity. However, these vending robots are faced with malfunctions linked to sensor jams. The identification of the jam phenomenon was possible thanks to the inspection and monitoring of the various sensors installed on the vending robot. And Cadence software was used to model, control and locate the jammed sensor(s). The various tests were carried out by setting the robot in motion to better understand the causes of the phenomenon. The jam is therefore the phenomenon which triggers the sensors permanently, which causes the automatic vending robot to stop functioning. And this jam was due to the presence of water droplets on the sensor or dirt. This presence of water droplets on the sensor is linked to an increase in temperature. Controlling the temperature and locating the jammed sensor has made it possible to considerably reduce jamming and its harmful effects on the vending machine robot. 展开更多
关键词 jam SENSOR Dispenser Robot
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JAM3基因DNA甲基化在宫颈高级别上皮内瘤变及术后复发预测的临床研究
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作者 娄琰琰 刘元涛 +4 位作者 赵淑婷 陈青 曹佃霞 公维涛 郝长宏 《临床医学进展》 2024年第7期1293-1299,共7页
目的:探讨JAM3 (junctional adhesion molecules 3)基因DNA甲基化水平在高级别上皮内瘤变中的诊断效能,实现宫颈癌精准筛查,协助高级别上皮内瘤变(cervical intraepithelial neoplasia, CIN) II~III级分级管理,预测术后复发风险,规范宫... 目的:探讨JAM3 (junctional adhesion molecules 3)基因DNA甲基化水平在高级别上皮内瘤变中的诊断效能,实现宫颈癌精准筛查,协助高级别上皮内瘤变(cervical intraepithelial neoplasia, CIN) II~III级分级管理,预测术后复发风险,规范宫颈上皮内瘤变治疗。研究方法:选择2020年1月至2023年1月就诊于临沂市中心医院需行宫颈活检术的200例病例,分别行HPV检查、液基细胞学检查、病理标本DNA甲基化检测。检测期间由一名固定医生取样。所有研究对象均通过阴道镜检查并进行宫颈组织病理学确诊后分组。根据病理学检查结果分为正常组、CIN I级组、CIN II级组、CIN III级组,各50例进行数据统计和临床分析。结果:正常组、CIN I级组、CIN II级组、CIN III级组JAM3基因甲基化者分别为4%、10%、38%、54%。随着宫颈病变程度的加重,JAM3基因的甲基化水平呈逐渐升高趋势。JAM3基因在正常组、CIN I组、CIN II组、CIN III组任意两组之间均存在显著差异(P < 0.01)。联合JAM3基因甲基化检测可弥补HPV低特异性及TCT低敏感性的缺陷,复发患者甲基化水平明显高于治愈者,差异具有统计学意义。结论:JAM3甲基化检测可显著提高宫颈高级别上皮内瘤变检出率,可为阴道镜检查不满意的LSIL患者分流管理提供参考;协助CIN II~III分级管理,提高病理诊断一致性;JAM3甲基化可作为高级别上皮内瘤变术后复发预测标志物。 展开更多
关键词 宫颈高级别上皮内瘤变 jam3基因 DNA甲基化 预测
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Nutritional, Chemical and Organoleptical Characteristics of Low-Calorie Fruit Nectars Incorporating Stevioside as a Natural Sweetener 被引量:1
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作者 Hassan Barakat Abdulaziz Al-Furaydi +1 位作者 Abdulelah Al-Harbi Ali Al-Shedookhi 《Food and Nutrition Sciences》 2017年第1期126-140,共15页
The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepar... The study is aiming at preparation of low-calorie fruit nectars for diabetes and weight maintaining approaches as well as consumer satisfaction. Therefore, twenty low-calorie fruit-based formulated nectars were prepared mainly from orange, pomegranate, guava and mango pulps which sweetened with sucrose or sucrose— replaced at 25%, 50%, 75% and 100% using stevioside. Primitively, the yield of fresh fruits had been calculated. Consequently, nutritional, chemical and organoleptical characteristics of prepared fruit nectars have been determined. Results indicated that total solids content was in range of 5.57% - 13.20%, 9.90% - 14.37%, 8.25% - 13.27% and 8.25% - 16.50% for orange, pomegranate, guava and mango nectars, respectively. Dependently, caloric value resulted 21.57 to 51.08, 38.31 to 55.62, 31.93 to 51.37 and 31.93 to 63.86 kcal 100 g-1 fw for orange, pomegranate, guava and mango nectars, respectively. Total phenols content [TPC, mg GAE 100 g-1 dw] ranged from 665.12 to 747.41, 1180.42 to 1319.47, 742.54 to 848.27 and 418.01 to 472.42 for orange, pomegranate, guava and mango nectars, respectively. The antioxidant capacity by DPPH method [μmol TE g-1 dw] ranged from (20.79 to 26.51), (47.13 to 56.56), (60.68 to 69.25) and (8.39 to 13.32) for orange, pomegranate, guava and mango nectars, respectively. Total carotenoids [mg 100 g-1 dw] were the highest in mango nectars ranged from (102.99 to 110.52) in mango nectar with 100% sugar and mango nectar with 100% stevioside, respectively. Anthocyanins content recorded 6.14 mg 100 g-1 dw in pomegranate nectar with 100% sugar, while increased to be 9.01 mg 00 g-1 dw in pomegranate nectar with 100% stevioside. Ascorbic acid [mg 100 g fw] ranged from 23.41 to 27.53, 15.73 to 18.32, 25.72 to 30.87 and 18.07 to 20.98 for orange, pomegranate, guava and mango nectars, respectively. The results of organoleptical attributes showed no effect of sugar substituting by stevioside on color, odor and mouth feel. The most dramatic effect of sugar substituting had been observed on taste, bitter after taste and the overall acceptability of prepared nectars with high substitution levels. Practically, using stevioside to produce low-calorie nectars was shown to be satisfactory up to 50% - 75% substituting level, resulting low-calorie nectars and could be applied commercially. 展开更多
关键词 low-calorie Nectar CHEMICAL NUTRITIONAL Organoleptical CHARACTERISTICS
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Open World Recognition of Communication Jamming Signals 被引量:3
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作者 Yan Tang Zhijin Zhao +4 位作者 Jie Chen Shilian Zheng Xueyi Ye Caiyi Lou Xiaoniu Yang 《China Communications》 SCIE CSCD 2023年第6期199-214,共16页
To improve the recognition ability of communication jamming signals,Siamese Neural Network-based Open World Recognition(SNNOWR)is proposed.The algorithm can recognize known jamming classes,detect new(unknown)jamming c... To improve the recognition ability of communication jamming signals,Siamese Neural Network-based Open World Recognition(SNNOWR)is proposed.The algorithm can recognize known jamming classes,detect new(unknown)jamming classes,and unsupervised cluseter new classes.The network of SNN-OWR is trained supervised with paired input data consisting of two samples from a known dataset.On the one hand,the network is required to have the ability to distinguish whether two samples are from the same class.On the other hand,the latent distribution of known class is forced to approach their own unique Gaussian distribution,which is prepared for the subsequent open set testing.During the test,the unknown class detection process based on Gaussian probability density function threshold is designed,and an unsupervised clustering algorithm of the unknown jamming is realized by using the prior knowledge of known classes.The simulation results show that when the jamming-to-noise ratio is more than 0d B,the accuracy of SNN-OWR algorithm for known jamming classes recognition,unknown jamming detection and unsupervised clustering of unknown jamming is about 95%.This indicates that the SNN-OWR algorithm can make the effect of the recognition of unknown jamming be almost the same as that of known jamming. 展开更多
关键词 communication jamming signals Siamese Neural Network Open World Recognition unsupervised clustering of new jamming type Gaussian probability density function
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Jamming-Aided Secure Communication in Ultra-Dense LEO Integrated Satellite-Terrestrial Networks 被引量:2
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作者 Yongpeng Shi Jiajia Liu +1 位作者 Jiadai Wang Yijie Xun 《China Communications》 SCIE CSCD 2023年第7期43-56,共14页
The ultra-dense low earth orbit(LEO)integrated satellite-terrestrial networks(UDLEO-ISTN)can bring lots of benefits in terms of wide coverage,high capacity,and strong robustness.Meanwhile,the broadcasting and open nat... The ultra-dense low earth orbit(LEO)integrated satellite-terrestrial networks(UDLEO-ISTN)can bring lots of benefits in terms of wide coverage,high capacity,and strong robustness.Meanwhile,the broadcasting and open natures of satellite links also reveal many challenges for transmission security protection,especially for eavesdropping defence.How to efficiently take advantage of the LEO satellite’s density and ensure the secure communication by leveraging physical layer security with the cooperation of jammers deserves further investigation.To our knowledge,using satellites as jammers in UDLEO-ISTN is still a new problem since existing works mainly focused on this issue only from the aspect of terrestrial networks.To this end,we study in this paper the cooperative secrecy communication problem in UDLEOISTN by utilizing several satellites to send jamming signal to the eavesdroppers.An iterative scheme is proposed as our solution to maximize the system secrecy energy efficiency(SEE)via jointly optimizing transmit power allocation and user association.Extensive experiment results verify that our designed optimization scheme can significantly enhance the system SEE and achieve the optimal power allocation and user association strategies. 展开更多
关键词 ultra-dense LEO satellite integrated satellite-terrestrial network physical layer security cooperative jamming
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Received Power Based Unmanned Aerial Vehicles (UAVs) Jamming Detection and Nodes Classification Using Machine Learning 被引量:1
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作者 Waleed Aldosari 《Computers, Materials & Continua》 SCIE EI 2023年第4期1253-1269,共17页
This paper presents a machine-learning method for detecting jamming UAVs and classifying nodes during jamming attacks onWireless Sensor Networks(WSNs).Jamming is a type of Denial of Service(DoS)attack and intentional ... This paper presents a machine-learning method for detecting jamming UAVs and classifying nodes during jamming attacks onWireless Sensor Networks(WSNs).Jamming is a type of Denial of Service(DoS)attack and intentional interference where a malicious node transmits a high-power signal to increase noise on the receiver side to disrupt the communication channel and reduce performance significantly.To defend and prevent such attacks,the first step is to detect them.The current detection approaches use centralized techniques to detect jamming,where each node collects information and forwards it to the base station.As a result,overhead and communication costs increased.In this work,we present a jamming attack and classify nodes into different categories based on their location to the jammer by employing a single node observer.As a result,we introduced a machine learning model that uses distance ratios and power received as features to detect such attacks.Furthermore,we considered several types of jammers transmitting at different power levels to evaluate the proposed metrics using MATLAB.With a detection accuracy of 99.7%for the k-nearest neighbors(KNN)algorithm and average testing accuracy of 99.9%,the presented solution is capable of efficiently and accurately detecting jamming attacks in wireless sensor networks. 展开更多
关键词 jamming attacks machine learning unmanned aerial vehicle(UAV) WSNS
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Towards reinforcement learning in UAV relay for anti-jamming maritime communications
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作者 Chuhuan Liu Yi Zhang +3 位作者 Guohang Niu Luliang Jia Liang Xiao Jiangxia Luan 《Digital Communications and Networks》 SCIE CSCD 2023年第6期1477-1485,共9页
Maritime communications with sea surface reflections and sea wave occlusions are susceptible to jamming attacks due to the wide geographical area and intensive wireless communication services.Unmanned Aerial Vehicles(... Maritime communications with sea surface reflections and sea wave occlusions are susceptible to jamming attacks due to the wide geographical area and intensive wireless communication services.Unmanned Aerial Vehicles(UAVs)help relay messages to improve communication performance,but the relay policy that depends on the rapidly changing maritime environments is difficult to optimize.In this paper,a reinforcement learning-based UAV relay policy for maritime communications is proposed to resist jamming attacks.Based on previous transmission performance,the relay location,the received power of the transmitted signal and the received jamming power,this scheme optimizes the UAV trajectory and relay power to save the energy consumption and decrease the Bit-Error-Rate(BER)of the maritime signals.A deep reinforcement learning-based scheme is also proposed,which designs a deep neural network with dueling architecture to further improve the communication performance and computational complexity.The performance bounds regarding the signal to interference plus noise ratio,energy consumption and the communication utility are provided based on the Nash equilibrium of the game against jamming,and the computational complexity of the proposed schemes is analyzed.Simulation results show that the proposed schemes improve the energy efficiency and decrease the BER compared with the benchmark. 展开更多
关键词 Maritime communications jamming Unmanned aerial vehicle RELAY Reinforcement learning
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Numerical Analyses of Ice Jamming in Jacket Platform Conductor Array in Bohai Sea
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作者 ZHAI Bi-yao YANG Fan +1 位作者 PAN Jun-ning XIE Dong-mei 《China Ocean Engineering》 SCIE EI CSCD 2023年第6期885-896,共12页
Serious ice accumulating,pile-up and ice jamming occur around the conductor array of offshore jacket platforms during the winter every year in Bohai Sea,which could cause grave threats to the stability of platform str... Serious ice accumulating,pile-up and ice jamming occur around the conductor array of offshore jacket platforms during the winter every year in Bohai Sea,which could cause grave threats to the stability of platform structure,the safety of people and equipment,and even severer calamity.Therefore,the process of ice accumulation and ice jamming in the jacket platform area needs more concern.This study focuses on ice accumulation and jamming behaviors in the jacket platform conductor area by using a coupled two-dimensional hydro-ice dynamics model.A series of cases are conducted with different flow conditions,such as flow velocity,drifting direction and oscillatory flow.Through the simulation,the ice pile-up process is described and changes in ice-jamming thickness,ice pile-up location and ice pile-up volume are investigated.The differences in ice pile-up in the steady flow and oscillatory flow are analyzed.This study proposes a new approach to simulate the ice jamming process in the jacket platform conductor area,providing a reference for ice management on the platform. 展开更多
关键词 sea ice ice jamming conductor array numerical modeling hydro-ice dynamics
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Joint target assignment and power allocation in the netted C-MIMO radar when tracking multi-targets in the presence of self-defense blanket jamming
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作者 Zhengjie Li Junwei Xie +1 位作者 Haowei Zhang Jiahao Xie 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2023年第6期414-427,共14页
The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In t... The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In this paper,based on the netted collocated multiple input multiple output(CMIMO)radar,an effective joint target assignment and power allocation(JTAPA)strategy for tracking multi-targets under self-defense blanket jamming is proposed.An architecture based on the distributed fusion is used in the radar network to estimate target state parameters.By deriving the predicted conditional Cramer-Rao lower bound(PC-CRLB)based on the obtained state estimation information,the objective function is formulated.To maximize the worst case tracking accuracy,the proposed JTAPA strategy implements an online target assignment and power allocation of all active nodes,subject to some resource constraints.Since the formulated JTAPA is non-convex,we propose an efficient two-step solution strategy.In terms of the simulation results,the proposed algorithm can effectively improve tracking performance in the worst case. 展开更多
关键词 Netted radar system MIMO Target assignment Power allocation Multi-targets tracking Self-defense blanket jamming
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Characterizing Peak-Time Traffic Jam Incidents in Kampala Using Exploratory Data Analysis
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作者 Sekalema Hamza Umar Yahya +3 位作者 Abdal Kasule Kasagga Usama Pembe Fahad Kamoga Ibrahim 《Journal of Transportation Technologies》 2023年第1期61-86,共26页
Traffic congestion is associated with increased environmental pollutions, as well as reduced socio-economic productivity due to significant delays in travel times. The consequences are worse in least developed countri... Traffic congestion is associated with increased environmental pollutions, as well as reduced socio-economic productivity due to significant delays in travel times. The consequences are worse in least developed countries where motorized road transport networks are often inefficiently managed in addition to being largely underdeveloped. Recent research on traffic congestion has mostly focused on infrastructural aspects of road networks, with little or no emphasis at all on motorists’ on-the-road behavior (MB). The current study thus aimed to bridge this knowledge gap by characterizing traffic jam incidents (TJI) observed over a period of 80 days in Uganda’s Capital City, Kampala. MB as well as road network infrastructural factors such as road blockage (RB), were captured for each of the observed TJI. A total of 483 peak-time TJI were recorded, and exploratory data analysis (EDA) subsequently performed on the TJI dataset. EDA involved Hierarchical clustering analysis (HCA) and K-means clustering of the TJI dataset, as well as a detailed descriptive statistical analysis of both the entire dataset and the emerging TJI clusters. A highlight finding of this study is that 48.2% of the observed TJIs were as a result of on-the-road motorist behavior. Furthermore, the intervention of traffic police officers in a bid to regulate traffic flow was equally responsible for 25.9% of the TJIs observed in this study. Overall, these results indicate that whereas road infrastructural improvement is warranted in order to improve traffic flow, introducing interventions to address inappropriate on-the-road motorists’ behavior could alone improve traffic flow in Kampala, by over 48%. Additionally, in-order to effectively regulate traffic flow in Kampala and other least developed cities with similar traffic congestion management practices, motorists’ on-the-road behavior ought to be factored into any data-driven mechanisms deployed to regulate traffic flow and thus potentially significantly curbing traffic congestion. 展开更多
关键词 Motorist Behavior Traffic jam Traffic Congestion Urban Road-Networks Motorized Transport Traffic Clusters
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Cognitive J^(2)SAC:Joint Jamming,Sensing,and Communication Under Antagonistic Environment
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作者 Jiangchun Gu Guoru Ding +3 位作者 Yizhen Yin Haichao Wang Yitao Xu Yehui Song 《China Communications》 SCIE CSCD 2023年第9期78-95,共18页
Integrated sensing and communication(ISAC)is regarded as a recent advanced technology,which is expected to realize the dual functions of sensing and communication simultaneously in one system.Nevertheless,it still fac... Integrated sensing and communication(ISAC)is regarded as a recent advanced technology,which is expected to realize the dual functions of sensing and communication simultaneously in one system.Nevertheless,it still faces the challenges of the information security and transmission robustness caused by the openness of wireless channel,especially under antagonistic environment.Hence,this article develops a generalized framework,named cognitive joint jamming,sensing and communication(cognitive J2SAC),to empower the current sensing/communication/jamming system with a“brain”for realizing precise sensing,reliable communication and effective jamming under antagonistic environment.Three kinds of gains can be captured by cognitive J2SAC,including integrated gain,cooperative gain and cognitive gain.Moreover,we highlight the enabling mechanism among jamming,sensing,and communication,as well as illustrating several typical use cases of cognitive J2SAC.Furthermore,several key enabled technologies are analyzed and a typical sensing enhance integrated communication and jamming case study is discussed to verify the effectiveness of the proposed method.Last but not the least,the future directions are listed before concluding this article.Integrated sensing and communication(ISAC)is regarded as a recent advanced technology,which is expected to realize the dual functions of sensing and communication simultaneously in one system.Nevertheless,it still faces the challenges of the information security and transmission robustness caused by the openness of wireless channel,especially under antagonistic environment.Hence,this article develops a generalized framework,named cognitive joint jamming,sensing and communication(cognitive J2SAC),to empower the current sensing/communication/jamming system with a“brain”for realizing precise sensing,reliable communication and effective jamming under antagonistic environment.Three kinds of gains can be captured by cognitive J2SAC,including integrated gain,cooperative gain and cognitive gain.Moreover,we highlight the enabling mechanism among jamming,sensing,and communication,as well as illustrating several typical use cases of cognitive J2SAC.Furthermore,several key enabled technologies are analyzed and a typical sensing enhance integrated communication and jamming case study is discussed to verify the effectiveness of the proposed method.Last but not the least,the future directions are listed before concluding this article. 展开更多
关键词 integrated sensing and communication(ISAC) information security joint jamming sensing and communication(J2SAC) cognition theory
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混合阻塞变刚度软手指设计与实验 被引量:1
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作者 李东民 马文平 +3 位作者 王雨 方佳琪 张国辉 丁国伟 《农业机械学报》 EI CAS CSCD 北大核心 2024年第1期436-445,458,共11页
为了解决单一阻塞介质变刚度软机械手抓取复杂外形物体效果不佳的问题,受人体手指结构启发,设计了一种仿指腹结构的混合阻塞变刚度软手指。将其设计为双层结构,外层为气动驱动器,内层为基于主动层干扰与被动颗粒阻塞的混合阻塞变刚度层... 为了解决单一阻塞介质变刚度软机械手抓取复杂外形物体效果不佳的问题,受人体手指结构启发,设计了一种仿指腹结构的混合阻塞变刚度软手指。将其设计为双层结构,外层为气动驱动器,内层为基于主动层干扰与被动颗粒阻塞的混合阻塞变刚度层,使得软手指自动贴合被抓取对象,实现主动驱动的被动适应,并通过调整刚度实现可靠抓取。基于传统缝纫工艺,采用超弹性硅胶材料制造软手指。采用Euler-Bernoulli梁理论和虚功原理,建立了基于悬臂梁结构下的多材料软手指的刚度控制模型,并据此提出增大整体刚度的材料筛选方法。弯曲特性实验表明软手指的弯曲性能优异。变刚度和抓取实验结果表明,混合阻塞软手指刚度增大4.6倍,建立的刚度模型最大相对误差为3.4%;在抓取对象表面粗糙度增大的条件下,软手指拉脱力仍增大17%,达到1.7 N;相较于单阻塞介质软手指,抓取成功率和承载能力均得到显著提高。 展开更多
关键词 软手指 变刚度 混合阻塞 层干扰
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智能反射面辅助的抗干扰安全通信系统鲁棒资源分配算法 被引量:1
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作者 席兵 冯彦博 +1 位作者 邓炳光 张治中 《电子与信息学报》 EI CAS CSCD 北大核心 2024年第3期875-885,共11页
为了解决恶意干扰攻击、窃听和不完美信道状态信息造成的通信质量降低和安全性差等问题,该文提出一种智能反射面(IRS)辅助的抗干扰安全通信系统鲁棒资源分配算法。首先,基于合法用户的最小安全速率约束、最大发射功率约束和IRS相移约束... 为了解决恶意干扰攻击、窃听和不完美信道状态信息造成的通信质量降低和安全性差等问题,该文提出一种智能反射面(IRS)辅助的抗干扰安全通信系统鲁棒资源分配算法。首先,基于合法用户的最小安全速率约束、最大发射功率约束和IRS相移约束,在非法节点不完美信道状态信息、干扰器波束成形向量未知的情况下,构建了一个联合优化基站的波束成形向量、人工噪声的协方差矩阵和IRS的相移矩阵的鲁棒资源分配问题。其次,为了求解该非凸问题,利用交替优化、Cauchy-Schwarz不等式、连续凸逼近和泰勒级数展开等方法,将原问题转化为易于求解的凸优化问题。仿真结果表明,与传统算法相比所提算法能有效提高系统安全性、降低功率开销、提高抗干扰裕度,且在一定信道误差范围内能够减低约35%的保密中断概率,具有较强的鲁棒性。 展开更多
关键词 物理层安全 智能反射面 抗干扰 鲁棒性 人工噪声
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