Cognitive Radio Networks(CRNs)have become a successful platform in recent years for a diverse range of future systems,in particularly,industrial internet of things(IIoT)applications.In order to provide an efficient co...Cognitive Radio Networks(CRNs)have become a successful platform in recent years for a diverse range of future systems,in particularly,industrial internet of things(IIoT)applications.In order to provide an efficient connection among IIoT devices,CRNs enhance spectrum utilization by using licensed spectrum.However,the routing protocol in these networks is considered one of the main problems due to node mobility and time-variant channel selection.Specifically,the channel selection for routing protocol is indispensable in CRNs to provide an adequate adaptation to the Primary User(PU)activity and create a robust routing path.This study aims to construct a robust routing path by minimizing PU interference and routing delay to maximize throughput within the IIoT domain.Thus,a generic routing framework from a cross-layer perspective is investigated that intends to share the information resources by exploiting a recently proposed method,namely,Channel Availability Probability.Moreover,a novel cross-layer-oriented routing protocol is proposed by using a time-variant channel estimation technique.This protocol combines lower layer(Physical layer and Data Link layer)sensing that is derived from the channel estimation model.Also,it periodically updates and stores the routing table for optimal route decision-making.Moreover,in order to achieve higher throughput and lower delay,a new routing metric is presented.To evaluate the performance of the proposed protocol,network simulations have been conducted and also compared to the widely used routing protocols,as a benchmark.The simulation results of different routing scenarios demonstrate that our proposed solution outperforms the existing protocols in terms of the standard network performance metrics involving packet delivery ratio(with an improved margin of around 5–20%approximately)under varying numbers of PUs and cognitive users in Mobile Cognitive Radio Networks(MCRNs).Moreover,the cross-layer routing protocol successfully achieves high routing performance in finding a robust route,selecting the high channel stability,and reducing the probability of PU interference for continued communication.展开更多
Key areas such as marine resource exploration,real-time monitoring of ecological environments,and national defense security systems urgently require reliable underwater information transmission capabilities as a found...Key areas such as marine resource exploration,real-time monitoring of ecological environments,and national defense security systems urgently require reliable underwater information transmission capabilities as a foundation.Underwater acoustic communication(UAC),leveraging its unique advantages as the most effective method for long-range data transfer in aquatic environments,has become an indispensable enabling technology for supporting these core applications.This review systematically examines recent advancements in UAC technology and their critical role in enabling modern marine initiatives.The analysis covers key developments in both non-coherent and coherent communication systems,including single-carrier and multi-carrier modulation schemes such as OFDM.It highlights their respective advantages in terms of robustness and high-data-rate transmission.The significant impact of challenging underwater channel characteristics,notably severe multipath fading,time-varying Doppler shifts,limited bandwidth,and environmental noise,is discussed alongside corresponding mitigation strategies.Furthermore,the integration of machine learning for sophisticated channel estimation,adaptive equalization,and intelligent system optimization is explored as a promising frontier.Emerging technologies like spread-spectrum,full-duplex,and covert UAC are also evaluated for their potential in specialized and high-stakes applications.The paper concludes by identifying persistent challenges,including regulatory constraints,physical-layer security issues,interoperability across platforms,and energy efficiency demands.Finally,it outlines future research directions aimed at developing more intelligent,secure,and efficient next-generation underwater networks.展开更多
In this paper we will discuss novel algorithms to develop the brain-computer interface (BCI) system in speller application based on single-trial classification of electroencephalogram (EEG) signal. The idea is to empl...In this paper we will discuss novel algorithms to develop the brain-computer interface (BCI) system in speller application based on single-trial classification of electroencephalogram (EEG) signal. The idea is to employ proper methods for reducing the number of channels and optimizing feature vectors. Removal unnecessary channels and reducing feature dimension result in cost decrement, time saving and improve the BCI implementation eventually. Optimal channels will be gotten after two stages sifting. In the first stage, the channels reduced up to 30% based on channels of the important event related potential (ERP) components and in the next stage, optimal channels were extracted by backward forward selection (BFS) algorithm. Also we will show that suitable single-trial analysis requires applying proper feature vector that was constructed by recognizing important ERP components, so as to propose an algorithm to distinguish less important features in feature vectors. F-Score criteria used to recognize effective features which created more discrimination between different classes and feature vectors were reconstructed based on effective features. Our algorithm has tested on dataset II of BCI competition III. The results show that we achieve accuracy up to 31% in single-trial, which is better than the performance of winner who is in this competition (about 25.5%). Also we use simple classifier and few channels to compute output performances while more complicated classifier and all channels are used by them.展开更多
Objective: to analyze the application value of calcium channel blocker in the treatment of coronary heart disease angina pectoris. Methods: a total of 100 cases of coronary heart disease patients with angina pectoris ...Objective: to analyze the application value of calcium channel blocker in the treatment of coronary heart disease angina pectoris. Methods: a total of 100 cases of coronary heart disease patients with angina pectoris admitted to our hospital from February 2019 to February 2020 were randomly divided into groups. Patients in the control group were treated with conventional methods, while patients in the observation group were additionally treated with calcium channel blockers. NBP, VAS score, left ventricular ejection fraction and overall outcome efficiency were compared between 2 groups before and after treatment. Results: before treatment, NBP, VAS score and left ventricular ejection fraction were compared between the two groups (P > 0.05). After treatment, NBP, VAS score of angina pectoris in the observation group was lower than that in the control group, while left ventricular ejection fraction was higher than that in the control group (P < 0.05). The total effective rate of observation group was 96.00% (48/50) higher than that of control group (80.00%, 40/50), P < 0.05. Conclusions: conventional drugs and calcium channel blockers have definite effects on coronary heart disease angina pectoris, which can improve cardiac function, relieve angina pectoris and improve serological indexes.展开更多
The poor interfacial stability not only deteriorates fibre lithium-ion batteries(FLBs)performance but also impacts their scalable applications.To efficiently address these challenges,Prof.Huisheng Peng team proposed a...The poor interfacial stability not only deteriorates fibre lithium-ion batteries(FLBs)performance but also impacts their scalable applications.To efficiently address these challenges,Prof.Huisheng Peng team proposed a generalized channel structures strategy with optimized in situ polymerization technology in their recent study.The resultant FLBs can be woven into different-sized powering textiles,providing a high energy density output of 128 Wh kg^(-1) and simultaneously demonstrating good durability even under harsh conditions.Such a promising strategy expands the horizon in developing FLB with particular polymer gel electrolytes,and significantly ever-deepening understanding of the scaled wearable energy textile system toward a sustainable future.展开更多
As immunotherapy gains increasing attention and clinical application,the immune modulation therapy has been widely used in the treatment of infectious andcriticaldiseases.Clinical evidencehas been accumulated forappli...As immunotherapy gains increasing attention and clinical application,the immune modulation therapy has been widely used in the treatment of infectious andcriticaldiseases.Clinical evidencehas been accumulated forapplication ofthymosin alpha1(Tα1),aclassicalimmune modulator,in related domains.The National Clinical Research Center for Infectious Diseases,National Medical Center for Infectious Diseases and other institu-tions invited multidisciplinary experts to develop this expert consensus on clinical application of Tα1 in infectious diseases and critical care med-icine.Based on the latest domestic and international research findings and considering relevant factors,including economics,patient preferences and values,tradeoffs,accessibility,fairness and acceptability,the consensus assesses the quality levels of current evidence and forms 10 recom-mendations on the application of Tα1 in treatment of liver diseases,viral infections,bacterial infections and critical illnesses.This consensus aims to enhance understanding of Tα1 and improving its standardized application for clinicians.展开更多
Distraction osteogenesis,or the Illizarov technique,induces bone regeneration using distractive mechanical forces.Nevertheless,Wolff's law holds that bone adapts to reverse compressive mechanical loads,growing den...Distraction osteogenesis,or the Illizarov technique,induces bone regeneration using distractive mechanical forces.Nevertheless,Wolff's law holds that bone adapts to reverse compressive mechanical loads,growing denser in areas of high pressure and resorbing in zones of low pressure.These two forms of new bone formation together suggest that mechanical stimuli play an important role in bone remodeling and regeneration.The therapeutic efficacy of distraction osteogenesis has been recognized in orthopedics and maxillofacial surgeries.Distraction osteogenesis was even used for the regeneration of various other tissues/organs,such as blood vessels and skin(e.g.,in the treatment of limb ischemic diseases and foot ulcers),suggesting the principle of distraction histogenesis.However,the underlying mechanisms,particularly those of the cross-organ effects and in terms of mechanotransduction,remain poorly understood.Thus,this review aims to explore the recent advances in research on musculoskeletal regeneration and its association with mechanosensitive channels from a new interdisciplinary application perspective.The contents can provide insights into potential research directions for understanding the molecular mechanisms of musculoskeletal regeneration and its clinical applications.展开更多
As unmanned aerial vehicles(UAV)deploy-ment is shifting from military to civilian sectors,and in particular as a means of facilitating more flexible and versatile wireless communications,the UAV channels that were pre...As unmanned aerial vehicles(UAV)deploy-ment is shifting from military to civilian sectors,and in particular as a means of facilitating more flexible and versatile wireless communications,the UAV channels that were previously not well understood are attracting increasing research and investigation.As the key component facilitating the UAV-aided communications,UAV channel characteristics and modeling are of critical importance to the designed UAV system to achieve satisfactory performance.In this article,we will provide a comprehensive overview and the future perspective of envisioned UAV communication system benefits,the existing and needed UAV channel measurements and modeling approaches,together with the new viewpoint of UAV channel applications in different communication and networking layers.Both existing work and future directions are extensively covered.展开更多
In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the...In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism. It is also compared with the present cleaning system with double channel applied to some combines, such as the Commandor 112CS/ 228CS combines of Claas Corporation in Germany and the MAXIMIZERTMombincs of John Deerc company in U.S.A. It may omit one sieve and the preclcaner and simlify the transmission mechanism. The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01 kg/ s.展开更多
The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia technology.High-quality images require well-tuned communication ...The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia technology.High-quality images require well-tuned communication standards.The Single Carrier Frequency Division Multiple Access(SC-FDMA)is adopted for broadband wireless communications,because of its low sensitivity to carrier frequency offsets and low Peak-to-Average Power Ratio(PAPR).Data transmission through open-channel networks requires much concentration on security,reliability,and integrity.The data need a space away fromunauthorized access,modification,or deletion.These requirements are to be fulfilled by digital image watermarking and encryption.This paper ismainly concerned with secure image communication over the wireless SC-FDMA systemas an adopted communication standard.It introduces a robust image communication framework over SC-FDMA that comprises digital image watermarking and encryption to improve image security,while maintaining a high-quality reconstruction of images at the receiver side.The proposed framework allows image watermarking based on the Discrete Cosine Transform(DCT)merged with the Singular Value Decomposition(SVD)in the so-called DCT-SVD watermarking.In addition,image encryption is implemented based on chaos and DNA encoding.The encrypted watermarked images are then transmitted through the wireless SC-FDMA system.The linearMinimumMean Square Error(MMSE)equalizer is investigated in this paper to mitigate the effect of channel fading and noise on the transmitted images.Two subcarrier mapping schemes,namely localized and interleaved schemes,are compared in this paper.The study depends on different channelmodels,namely PedestrianAandVehicularA,with a modulation technique namedQuadratureAmplitude Modulation(QAM).Extensive simulation experiments are conducted and introduced in this paper for efficient transmission of encrypted watermarked images.In addition,different variants of SC-FDMA based on the Discrete Wavelet Transform(DWT),Discrete Cosine Transform(DCT),and Fast Fourier Transform(FFT)are considered and compared for the image communication task.The simulation results and comparison demonstrate clearly that DWT-SC-FDMAis better suited to the transmission of the digital images in the case of PedestrianAchannels,while the DCT-SC-FDMA is better suited to the transmission of the digital images in the case of Vehicular A channels.展开更多
This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium.A discharge with a current amplitude of 10 kA,a dur...This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium.A discharge with a current amplitude of 10 kA,a duration of 400 ns,and an amplitude pulsed power of 280 MW in water at atmospheric pressure created an expanding acoustic wave with an amplitude of more than 100 MPa.To describe the formation of the discharge channel,an isothermal plasma model has been developed,which made it possible to calculate both the expansion dynamics of a high-current channel and the strong acoustic wave generated by it.Our calculations show that the number density of plasma in the channel reaches 10^(20) cm^(-3),while the degree of water vapor ionization is about 10%,and the channel wall extends with a velocity of 500 m s^(−1).The calculations for the acoustic wave are in good agreement with measurements.展开更多
A video patrol and inspection system is an important part of the government's shipping channel information management. This system is mainly applied to video information gathering and processing as a patrol is car...A video patrol and inspection system is an important part of the government's shipping channel information management. This system is mainly applied to video information gathering and processing as a patrol is carried out. The system described in this paper can preview,edit,and add essential explanation messages to the collected video data. It then transfers these data and messages to a video server for the leaders and engineering and technical personnel to re-trieve,play,chart,download or print. Each department of the government will use the system's functions according to that department's mission. The system can provide an effective means for managing the shipping enterprise. It also pro-vides a valuable reference for the modernizing of waterborne shipping.展开更多
文摘Cognitive Radio Networks(CRNs)have become a successful platform in recent years for a diverse range of future systems,in particularly,industrial internet of things(IIoT)applications.In order to provide an efficient connection among IIoT devices,CRNs enhance spectrum utilization by using licensed spectrum.However,the routing protocol in these networks is considered one of the main problems due to node mobility and time-variant channel selection.Specifically,the channel selection for routing protocol is indispensable in CRNs to provide an adequate adaptation to the Primary User(PU)activity and create a robust routing path.This study aims to construct a robust routing path by minimizing PU interference and routing delay to maximize throughput within the IIoT domain.Thus,a generic routing framework from a cross-layer perspective is investigated that intends to share the information resources by exploiting a recently proposed method,namely,Channel Availability Probability.Moreover,a novel cross-layer-oriented routing protocol is proposed by using a time-variant channel estimation technique.This protocol combines lower layer(Physical layer and Data Link layer)sensing that is derived from the channel estimation model.Also,it periodically updates and stores the routing table for optimal route decision-making.Moreover,in order to achieve higher throughput and lower delay,a new routing metric is presented.To evaluate the performance of the proposed protocol,network simulations have been conducted and also compared to the widely used routing protocols,as a benchmark.The simulation results of different routing scenarios demonstrate that our proposed solution outperforms the existing protocols in terms of the standard network performance metrics involving packet delivery ratio(with an improved margin of around 5–20%approximately)under varying numbers of PUs and cognitive users in Mobile Cognitive Radio Networks(MCRNs).Moreover,the cross-layer routing protocol successfully achieves high routing performance in finding a robust route,selecting the high channel stability,and reducing the probability of PU interference for continued communication.
文摘Key areas such as marine resource exploration,real-time monitoring of ecological environments,and national defense security systems urgently require reliable underwater information transmission capabilities as a foundation.Underwater acoustic communication(UAC),leveraging its unique advantages as the most effective method for long-range data transfer in aquatic environments,has become an indispensable enabling technology for supporting these core applications.This review systematically examines recent advancements in UAC technology and their critical role in enabling modern marine initiatives.The analysis covers key developments in both non-coherent and coherent communication systems,including single-carrier and multi-carrier modulation schemes such as OFDM.It highlights their respective advantages in terms of robustness and high-data-rate transmission.The significant impact of challenging underwater channel characteristics,notably severe multipath fading,time-varying Doppler shifts,limited bandwidth,and environmental noise,is discussed alongside corresponding mitigation strategies.Furthermore,the integration of machine learning for sophisticated channel estimation,adaptive equalization,and intelligent system optimization is explored as a promising frontier.Emerging technologies like spread-spectrum,full-duplex,and covert UAC are also evaluated for their potential in specialized and high-stakes applications.The paper concludes by identifying persistent challenges,including regulatory constraints,physical-layer security issues,interoperability across platforms,and energy efficiency demands.Finally,it outlines future research directions aimed at developing more intelligent,secure,and efficient next-generation underwater networks.
文摘In this paper we will discuss novel algorithms to develop the brain-computer interface (BCI) system in speller application based on single-trial classification of electroencephalogram (EEG) signal. The idea is to employ proper methods for reducing the number of channels and optimizing feature vectors. Removal unnecessary channels and reducing feature dimension result in cost decrement, time saving and improve the BCI implementation eventually. Optimal channels will be gotten after two stages sifting. In the first stage, the channels reduced up to 30% based on channels of the important event related potential (ERP) components and in the next stage, optimal channels were extracted by backward forward selection (BFS) algorithm. Also we will show that suitable single-trial analysis requires applying proper feature vector that was constructed by recognizing important ERP components, so as to propose an algorithm to distinguish less important features in feature vectors. F-Score criteria used to recognize effective features which created more discrimination between different classes and feature vectors were reconstructed based on effective features. Our algorithm has tested on dataset II of BCI competition III. The results show that we achieve accuracy up to 31% in single-trial, which is better than the performance of winner who is in this competition (about 25.5%). Also we use simple classifier and few channels to compute output performances while more complicated classifier and all channels are used by them.
文摘Objective: to analyze the application value of calcium channel blocker in the treatment of coronary heart disease angina pectoris. Methods: a total of 100 cases of coronary heart disease patients with angina pectoris admitted to our hospital from February 2019 to February 2020 were randomly divided into groups. Patients in the control group were treated with conventional methods, while patients in the observation group were additionally treated with calcium channel blockers. NBP, VAS score, left ventricular ejection fraction and overall outcome efficiency were compared between 2 groups before and after treatment. Results: before treatment, NBP, VAS score and left ventricular ejection fraction were compared between the two groups (P > 0.05). After treatment, NBP, VAS score of angina pectoris in the observation group was lower than that in the control group, while left ventricular ejection fraction was higher than that in the control group (P < 0.05). The total effective rate of observation group was 96.00% (48/50) higher than that of control group (80.00%, 40/50), P < 0.05. Conclusions: conventional drugs and calcium channel blockers have definite effects on coronary heart disease angina pectoris, which can improve cardiac function, relieve angina pectoris and improve serological indexes.
基金the National Key R&D Program of China(2022YFA1203304)the Natural Science Foundation of Jiangsu Province(BK20220288)+1 种基金Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(Start-up grant E1552102)the China Postdoctoral Science Foundation(No.2023M732553).
文摘The poor interfacial stability not only deteriorates fibre lithium-ion batteries(FLBs)performance but also impacts their scalable applications.To efficiently address these challenges,Prof.Huisheng Peng team proposed a generalized channel structures strategy with optimized in situ polymerization technology in their recent study.The resultant FLBs can be woven into different-sized powering textiles,providing a high energy density output of 128 Wh kg^(-1) and simultaneously demonstrating good durability even under harsh conditions.Such a promising strategy expands the horizon in developing FLB with particular polymer gel electrolytes,and significantly ever-deepening understanding of the scaled wearable energy textile system toward a sustainable future.
基金This work was supported by the National Key Research and Development Program of China(2022YFC2304500)the National Science and Technology Major Project of China(2017ZX10203201).
文摘As immunotherapy gains increasing attention and clinical application,the immune modulation therapy has been widely used in the treatment of infectious andcriticaldiseases.Clinical evidencehas been accumulated forapplication ofthymosin alpha1(Tα1),aclassicalimmune modulator,in related domains.The National Clinical Research Center for Infectious Diseases,National Medical Center for Infectious Diseases and other institu-tions invited multidisciplinary experts to develop this expert consensus on clinical application of Tα1 in infectious diseases and critical care med-icine.Based on the latest domestic and international research findings and considering relevant factors,including economics,patient preferences and values,tradeoffs,accessibility,fairness and acceptability,the consensus assesses the quality levels of current evidence and forms 10 recom-mendations on the application of Tα1 in treatment of liver diseases,viral infections,bacterial infections and critical illnesses.This consensus aims to enhance understanding of Tα1 and improving its standardized application for clinicians.
基金supported by grants from the National Natural Science Foundation of China(No.82360429 and 82060406)Natural Science Foundation of Guangxi,China(No.2023GXNSFAA026474)+1 种基金Advanced Innovation Teams and Xinghu Scholars Program of Guangxi Medical University,China Postdoctoral Science Foundation(No.2019M650235)Key R&D Project of Qingxiu District,Nanning,Guangxi,China(No.2021003).
文摘Distraction osteogenesis,or the Illizarov technique,induces bone regeneration using distractive mechanical forces.Nevertheless,Wolff's law holds that bone adapts to reverse compressive mechanical loads,growing denser in areas of high pressure and resorbing in zones of low pressure.These two forms of new bone formation together suggest that mechanical stimuli play an important role in bone remodeling and regeneration.The therapeutic efficacy of distraction osteogenesis has been recognized in orthopedics and maxillofacial surgeries.Distraction osteogenesis was even used for the regeneration of various other tissues/organs,such as blood vessels and skin(e.g.,in the treatment of limb ischemic diseases and foot ulcers),suggesting the principle of distraction histogenesis.However,the underlying mechanisms,particularly those of the cross-organ effects and in terms of mechanotransduction,remain poorly understood.Thus,this review aims to explore the recent advances in research on musculoskeletal regeneration and its association with mechanosensitive channels from a new interdisciplinary application perspective.The contents can provide insights into potential research directions for understanding the molecular mechanisms of musculoskeletal regeneration and its clinical applications.
基金supported by the Ministry National Key Research and Development Project under Grant 2017YFE0121400the National Science and Technology Major Project under Grant 2018ZX03001031+3 种基金Shenzhen Fundamental Research Fund under Grant No.JCYJ20170411102217994Guangdong province under grant No.2017ZT07X152the Open Research Fund from Shenzhen Research Institute of Big Data under Grant No.2019ORF01006the National Natural Science Foundation of China under Grants 61622101 and 61571020.
文摘As unmanned aerial vehicles(UAV)deploy-ment is shifting from military to civilian sectors,and in particular as a means of facilitating more flexible and versatile wireless communications,the UAV channels that were previously not well understood are attracting increasing research and investigation.As the key component facilitating the UAV-aided communications,UAV channel characteristics and modeling are of critical importance to the designed UAV system to achieve satisfactory performance.In this article,we will provide a comprehensive overview and the future perspective of envisioned UAV communication system benefits,the existing and needed UAV channel measurements and modeling approaches,together with the new viewpoint of UAV channel applications in different communication and networking layers.Both existing work and future directions are extensively covered.
文摘In this paper the application of a cleaning system which was made up of a centrifugal fan with double channel and one sieve to 4LZ-3.5 combine was introduced. This cleaning system with double channel compared with the traditional air-sieve cleaning system of combines may omit one two sieves and simplify the transmission mechanism. It is also compared with the present cleaning system with double channel applied to some combines, such as the Commandor 112CS/ 228CS combines of Claas Corporation in Germany and the MAXIMIZERTMombincs of John Deerc company in U.S.A. It may omit one sieve and the preclcaner and simlify the transmission mechanism. The measuring results indicated that the cleaning ratio of wheat grain is 99.1% and the cleaning loss ratio of wheat is 0.17% when the feed rate is 4.01 kg/ s.
基金the Deanship of Scientific Research,Princess Nourah bint Abdulrahman University,through the Program of Research Project Funding After Publication,Grant No.(44-PRFA-P-131).
文摘The efficient transmission of images,which plays a large role inwireless communication systems,poses a significant challenge in the growth of multimedia technology.High-quality images require well-tuned communication standards.The Single Carrier Frequency Division Multiple Access(SC-FDMA)is adopted for broadband wireless communications,because of its low sensitivity to carrier frequency offsets and low Peak-to-Average Power Ratio(PAPR).Data transmission through open-channel networks requires much concentration on security,reliability,and integrity.The data need a space away fromunauthorized access,modification,or deletion.These requirements are to be fulfilled by digital image watermarking and encryption.This paper ismainly concerned with secure image communication over the wireless SC-FDMA systemas an adopted communication standard.It introduces a robust image communication framework over SC-FDMA that comprises digital image watermarking and encryption to improve image security,while maintaining a high-quality reconstruction of images at the receiver side.The proposed framework allows image watermarking based on the Discrete Cosine Transform(DCT)merged with the Singular Value Decomposition(SVD)in the so-called DCT-SVD watermarking.In addition,image encryption is implemented based on chaos and DNA encoding.The encrypted watermarked images are then transmitted through the wireless SC-FDMA system.The linearMinimumMean Square Error(MMSE)equalizer is investigated in this paper to mitigate the effect of channel fading and noise on the transmitted images.Two subcarrier mapping schemes,namely localized and interleaved schemes,are compared in this paper.The study depends on different channelmodels,namely PedestrianAandVehicularA,with a modulation technique namedQuadratureAmplitude Modulation(QAM).Extensive simulation experiments are conducted and introduced in this paper for efficient transmission of encrypted watermarked images.In addition,different variants of SC-FDMA based on the Discrete Wavelet Transform(DWT),Discrete Cosine Transform(DCT),and Fast Fourier Transform(FFT)are considered and compared for the image communication task.The simulation results and comparison demonstrate clearly that DWT-SC-FDMAis better suited to the transmission of the digital images in the case of PedestrianAchannels,while the DCT-SC-FDMA is better suited to the transmission of the digital images in the case of Vehicular A channels.
基金carried out within the framework of the state assignment of the Ministry of Science and Higher Education of the Russian Federation on the topic(No.FWRM-20210001)the grant of the Russian Foundation for Basic Research(RFBR),project No.18-29-24079 mk。
文摘This paper presents the results of a theoretical and experimental study of the use of a pulsed discharge in water to obtain a strong acoustic wave in a liquid medium.A discharge with a current amplitude of 10 kA,a duration of 400 ns,and an amplitude pulsed power of 280 MW in water at atmospheric pressure created an expanding acoustic wave with an amplitude of more than 100 MPa.To describe the formation of the discharge channel,an isothermal plasma model has been developed,which made it possible to calculate both the expansion dynamics of a high-current channel and the strong acoustic wave generated by it.Our calculations show that the number density of plasma in the channel reaches 10^(20) cm^(-3),while the degree of water vapor ionization is about 10%,and the channel wall extends with a velocity of 500 m s^(−1).The calculations for the acoustic wave are in good agreement with measurements.
文摘A video patrol and inspection system is an important part of the government's shipping channel information management. This system is mainly applied to video information gathering and processing as a patrol is carried out. The system described in this paper can preview,edit,and add essential explanation messages to the collected video data. It then transfers these data and messages to a video server for the leaders and engineering and technical personnel to re-trieve,play,chart,download or print. Each department of the government will use the system's functions according to that department's mission. The system can provide an effective means for managing the shipping enterprise. It also pro-vides a valuable reference for the modernizing of waterborne shipping.
