A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken...A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken into account.A set of sufficient criteria for extinction(exponential extinction and extinction)and permanence(permanence in time average and stochastic permanence)of the system are established.Extensive simulation figures are demonstrated to support the theoretical findings.Meanwhile,we look at the effects of coupling white noises,impulses,intrinsic growth rates,intra-specific competition rates and inter-specific mutualism rates on the survival of populations.展开更多
Discrete-time analogue of mutualism model is introduced. The discrete-time analogues is considered to be numerical discretization of the continuous-time models and we study their dynamical characteristics. It is shown...Discrete-time analogue of mutualism model is introduced. The discrete-time analogues is considered to be numerical discretization of the continuous-time models and we study their dynamical characteristics. It is shown that the discrete-time analogues preserve the periodicity of the continuous-time models.展开更多
In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solution of a mutualism system with infinite delays. Our results generalize thos...In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solution of a mutualism system with infinite delays. Our results generalize those of Yang etc. [8] and Gopalsamy and He [7].展开更多
Understanding the cause of the synchronization of population evolution is an important issue for ecologicalimprovement.Here we present a Lotka-Volterra-type model driven by two correlated environmental noises and show...Understanding the cause of the synchronization of population evolution is an important issue for ecologicalimprovement.Here we present a Lotka-Volterra-type model driven by two correlated environmental noises and show,via theoretical analysis and direct simulation,that noise correlation can induce a synchronization of the mutualists.Thetime series of mutual species exhibit a chaotic-like fluctuation,which is independent of the noise correlation,however,the chaotic fluctuation of mutual species ratio decreases with the noise correlation.A quantitative parameter defined forcharacterizing chaotic fluctuation provides a good approach to measure when the complete synchronization happens.展开更多
In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly effi...In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.展开更多
[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mu...[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mutualism, conventional cultivation and control treatment, the yield and economic benefits were analyzed under the 3 treatments. [Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.0g ind/m^2 compared with that in conventional cultivation and control treatment ; the control rate of mutualism was up to 75% against rice hopper, but just between 25% -60% against rice leaf roller and Chilo suppressalis. The rates of diseased plant and diseased bell against rice sheath blight were higher and disease indices were lower compared with control group. The yield of mutualism group was identical with conventional cultivation, Which was greatly higher than that of control group. The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment. [Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases, insect pests and weeds, as well as to economic benefits, providing basis on extension of rice-duck mutualism system.展开更多
On the threshold of 55 years of diplomatic relations,Cyprus and China stand to gain significantly by deepening their cooperation in trade,tourism,and green technology,guided by mutual respect and shared principles.WIT...On the threshold of 55 years of diplomatic relations,Cyprus and China stand to gain significantly by deepening their cooperation in trade,tourism,and green technology,guided by mutual respect and shared principles.WITH a population of approximately one million,Cyprus is a small country compared to China,which is home to more than 1.4 billion people.展开更多
The year 2025 marks both the 25th anniversary of the Forum on China-Africa Cooperation(FOCAC)and the first year of implementation of the outcomes of the 2024 FOCAC Beijing Summit.Throughout the year,China has supporte...The year 2025 marks both the 25th anniversary of the Forum on China-Africa Cooperation(FOCAC)and the first year of implementation of the outcomes of the 2024 FOCAC Beijing Summit.Throughout the year,China has supported Africa in addressing historical injustices at diplomatic and political levels and firmly backed South Africa in hosting the G20 Leaders’Summit,further deepening China-Africa strategic mutual trust.展开更多
In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC compon...In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.展开更多
With the availability of low-cost radio frequency identification (RFID) tags,security becomes an increasing concern. However,such tags do not permit complex cryptographic functions due to their computational,communica...With the availability of low-cost radio frequency identification (RFID) tags,security becomes an increasing concern. However,such tags do not permit complex cryptographic functions due to their computational,communications,and storage limitations. In this paper,we investigate the security issues and requirements of RFID systems,and propose ultra-light weight and light weight protocols for low-cost RFID tags.The proposed protocols has been applied to a supply chain management system.展开更多
In network-connected UAV(NCUAV) communication systems, user authentication is replaced by platform identity authentication and integrity check because many NC-UAVs are operated without human intervention. Direct anony...In network-connected UAV(NCUAV) communication systems, user authentication is replaced by platform identity authentication and integrity check because many NC-UAVs are operated without human intervention. Direct anonymous attestation(DAA) is an attractive cryptographic scheme that provides an elegant balance between platform authentication and anonymity. However, because of the low-level computing capability and limited transmission bandwidth in UAV, the existing DAA schemes are not suitable for NC-UAV communication systems. In this paper, we propose an enhanced DAA scheme with mutual authentication(MA-DAA scheme), which meets the security requirements of NC-UAV communication systems. The proposed MA-DAA scheme, which is based on asymmetric pairings, bundles the identities of trusted platform module(TPM) and Host to solve the malicious module changing attacks. Credential randomization, batch proof and verification, and mutual authentication are realized in the MA-DAA scheme. The computational workload in TPM and Host is reduced in order to meet the low computation and resource requirements in TPM and Host.The entire scheme and protocols are presented,and the security and efficiency of the proposed MA-DAA scheme are proved and analyzed.Our experiment results also confirm the high efficiency of the proposed scheme.展开更多
Blockchain and multi-access edge com-puting(MEC)are two emerging promising tech-nologies that have received extensive attention from academia and industry.As a brand-new information storage,dissemination and managemen...Blockchain and multi-access edge com-puting(MEC)are two emerging promising tech-nologies that have received extensive attention from academia and industry.As a brand-new information storage,dissemination and management mechanism,blockchain technology achieves the reliable transmis-sion of data and value.While as a new computing paradigm,multi-access edge computing enables the high-frequency interaction and real-time transmission of data.The integration of communication and com-puting in blockchain-enabled multi-access edge com-puting networks has been studied without a systemat-ical view.In the survey,we focus on the integration of communication and computing,explores the mu-tual empowerment and mutual promotion effects be-tween the blockchain and MEC,and introduces the resource integration architecture of blockchain and multi-access edge computing.Then,the paper sum-marizes the applications of the resource integration ar-chitecture,resource management,data sharing,incen-tive mechanism,and consensus mechanism,and ana-lyzes corresponding applications in real-world scenar-ios.Finally,future challenges and potentially promis-ing research directions are discussed and present in de-tail.展开更多
Strong inductive coupling between the heating field and equilibrium field is confirmed to be responsible for the poor plasma equilibrium in initial discharges on the SUNIST spherical tokamak. A modification project fo...Strong inductive coupling between the heating field and equilibrium field is confirmed to be responsible for the poor plasma equilibrium in initial discharges on the SUNIST spherical tokamak. A modification project for the power supply system of equilibrium field coils is successfully performed to increase the duration time of plasma current flattop from much less than 1ms to about 2 ms.展开更多
Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main mo...Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main modules——data sources, 3D simulation terrain database, 3D simulation model database, 3D simulation implementation and application system. Then the key technoiogies of constructing Virtual Huanghe River System were discussed in detail： 1） OpenGL technology, the 3D graphics developing instrument, was employed in Virtual Huanghe River System to realize the function of dynamic real-time navigation. 2） MO and OpenGL technologies were used to make the mutual response between 3D scene and 2D electronic map available, which made use of the advantages of both 3D scene and 2D electronic map, with the macroscopic view, integrality and conciseness of 2D electronic map combined with the locality, reality and visualization of 3D scene. At the same time the disadvantages of abstract and ambiguity of 2D electronic map and the direction losing of virtual navigation in 3D scene were overcome.展开更多
In this paper, we focus on the power allocation of Integrated Sensing and Communication(ISAC) with orthogonal frequency division multiplexing(OFDM) waveform. In order to improve the spectrum utilization efficiency in ...In this paper, we focus on the power allocation of Integrated Sensing and Communication(ISAC) with orthogonal frequency division multiplexing(OFDM) waveform. In order to improve the spectrum utilization efficiency in ISAC, we propose a design scheme based on spectrum sharing, that is,to maximize the mutual information(MI) of radar sensing while ensuring certain communication rate and transmission power constraints. In the proposed scheme, three cases are considered for the scattering off the target due to the communication signals,as negligible signal, beneficial signal, and interference signal to radar sensing, respectively, thus requiring three power allocation schemes. However,the corresponding power allocation schemes are nonconvex and their closed-form solutions are unavailable as a consequence. Motivated by this, alternating optimization(AO), sequence convex programming(SCP) and Lagrange multiplier are individually combined for three suboptimal solutions corresponding with three power allocation schemes. By combining the three algorithms, we transform the non-convex problem which is difficult to deal with into a convex problem which is easy to solve and obtain the suboptimal solution of the corresponding optimization problem. Numerical results show that, compared with the allocation results of the existing algorithms, the proposed joint design algorithm significantly improves the radar performance.展开更多
In this paper, the temporal and spatial patterns of a diffusive predator-prey model with mutual interference under homogeneous Neumann boundary conditions were studied. Specifically, first, taking the intrinsic growth...In this paper, the temporal and spatial patterns of a diffusive predator-prey model with mutual interference under homogeneous Neumann boundary conditions were studied. Specifically, first, taking the intrinsic growth rate of the predator as the parameter, we give a computational and theoretical analysis of Hopf bifurcation on the positive equilibrium for the ODE system. As well, we have discussed the conditions for determining the bifurcation direction and the stability of the bifurcating periodic solutions.展开更多
Asia is the major producing area of aquatic products.In order to maintain the stability of fishery,some Asian countries have established a mutual insurance system,which,however,shows distinctive features in different ...Asia is the major producing area of aquatic products.In order to maintain the stability of fishery,some Asian countries have established a mutual insurance system,which,however,shows distinctive features in different countries as a result of their different historical,economic and social conditions.This paper introduced the development status and characteristics of the fishery mutual insurance system in some Asian countries,such as Japan,South Korea,India,etc.,and then summarized their experiences and what we can learn from their experiences from the perspectives of legislation,governmental support,mutual insurance associations,and credit.展开更多
Utilizing channel reciprocity, time reversal（TR） technique increases the signal-to-noise ratio（SNR） at the receiver with very low transmitter complexity in complex multipath environment. Present research works abo...Utilizing channel reciprocity, time reversal（TR） technique increases the signal-to-noise ratio（SNR） at the receiver with very low transmitter complexity in complex multipath environment. Present research works about TR multiple-input multiple-output（MIMO） communication all focus on the system implementation and network building. The aim of this work is to analyze the influence of antenna coupling on the capacity of wideband TR MIMO system, which is a realistic question in designing a practical communication system. It turns out that antenna coupling stabilizes the capacity in a small variation range with statistical wideband channel response. Meanwhile, antenna coupling only causes a slight detriment to the channel capacity in a wideband TR MIMO system. Comparatively, uncorrelated stochastic channels without coupling exhibit a wider range of random capacity distribution which greatly depends on the statistical channel. The conclusions drawn from information difference entropy theory provide a guideline for designing better high-performance wideband TR MIMO communication systems.展开更多
A micro-electromechanical system(MEMS)scanning mirror accelerates the raster scanning of optical-resolution photoacoustic microscopy(OR-PAM).However,the nonlinear tilt angular-voltage characteristic of a MEMS mirror i...A micro-electromechanical system(MEMS)scanning mirror accelerates the raster scanning of optical-resolution photoacoustic microscopy(OR-PAM).However,the nonlinear tilt angular-voltage characteristic of a MEMS mirror introduces distortion into the maximum back-projection image.Moreover,the size of the airy disk,ultrasonic sensor properties,and thermal effects decrease the resolution.Thus,in this study,we proposed a spatial weight matrix(SWM)with a dimensionality reduction for image reconstruction.The three-layer SWM contains the invariable information of the system,which includes a spatial dependent distortion correction and 3D deconvolution.We employed an ordinal-valued Markov random field and the Harris Stephen algorithm,as well as a modified delay-and-sum method during a time reversal.The results from the experiments and a quantitative analysis demonstrate that images can be effectively reconstructed using an SWM;this is also true for severely distorted images.The index of the mutual information between the reference images and registered images was 70.33 times higher than the initial index,on average.Moreover,the peak signal-to-noise ratio was increased by 17.08%after 3D deconvolution.This accomplishment offers a practical approach to image reconstruction and a promising method to achieve a real-time distortion correction for MEMS-based OR-PAM.展开更多
Wireless medical sensor networks(WMSNs)play a significant role in increasing the availability of remote healthcare systems.The vital and physiological data of the patient can be collected using the WMSN via sensor nod...Wireless medical sensor networks(WMSNs)play a significant role in increasing the availability of remote healthcare systems.The vital and physiological data of the patient can be collected using the WMSN via sensor nodes that are placed on his/her body and then transmitted remotely to a healthcare professional for proper diagnosis.The protection of the patient’s privacy and their data from unauthorized access is a major concern in such systems.Therefore,an authentication scheme with a high level of security is one of the most effective mechanisms by which to address these security concerns.Many authentication schemes for remote patient monitoring have been proposed recently.However,the majority of these schemes are extremely vulnerable to attacks and are unsuitable for practical use.This paper proposes a secure three-factor authentication scheme for a patient-monitoring healthcare system that operates remotely using a WMSN.The proposed authentication scheme is formally verified using the Burrows,Abadi and Needham’s(BAN)logic model and an automatic cryptographic protocol verifier(ProVerif)tool.We show that our authentication scheme can prevent relevant types of security breaches in a practical context according to the discussed possible attack scenarios.Comparisons of the security and performance are carried out with recently proposed authentication schemes.The results of the analysis show that the proposed authentication scheme is secure and practical for use,with reasonable storage space,computation,and communication efficiency.展开更多
文摘A system of impulsive stochastic differential equations is proposed as a two-species facultative mutualism model subject to impulsive and two coupling noise source perturbations,in which the saturation effect is taken into account.A set of sufficient criteria for extinction(exponential extinction and extinction)and permanence(permanence in time average and stochastic permanence)of the system are established.Extensive simulation figures are demonstrated to support the theoretical findings.Meanwhile,we look at the effects of coupling white noises,impulses,intrinsic growth rates,intra-specific competition rates and inter-specific mutualism rates on the survival of populations.
基金This work was supported by the Foundation of Developing Science and Technology of Fuzhou University under the grant 0030824594 and the Foundation of Fujian Education Bureau under the Grant JB03059.
文摘Discrete-time analogue of mutualism model is introduced. The discrete-time analogues is considered to be numerical discretization of the continuous-time models and we study their dynamical characteristics. It is shown that the discrete-time analogues preserve the periodicity of the continuous-time models.
基金This work was supported by the Foundation of Developing Science Technology of Fuzhou University under the grant 0030824594 the Foundation of Fujian Education Bureau under the Grant JB03059.
文摘In this paper, by using Mawhin coincidence degree, some sufficient conditions are obtained for the global existence of positive periodic solution of a mutualism system with infinite delays. Our results generalize those of Yang etc. [8] and Gopalsamy and He [7].
基金National Natural Science Foundation of China under Grant No.60471023
文摘Understanding the cause of the synchronization of population evolution is an important issue for ecologicalimprovement.Here we present a Lotka-Volterra-type model driven by two correlated environmental noises and show,via theoretical analysis and direct simulation,that noise correlation can induce a synchronization of the mutualists.Thetime series of mutual species exhibit a chaotic-like fluctuation,which is independent of the noise correlation,however,the chaotic fluctuation of mutual species ratio decreases with the noise correlation.A quantitative parameter defined forcharacterizing chaotic fluctuation provides a good approach to measure when the complete synchronization happens.
基金Supported by Major Project of School-level Teaching Reform and Research of Guangxi University of Chinese Medicine(2022A006)。
文摘In comparison with conventional experimental teaching methods,the implementation of the Motic digital microscope mutual system in the experimental teaching of medicinal botany has been demonstrated to be a highly efficacious approach to enhance the teaching level of experimental courses in medicinal botany.The implementation of a digital microscope mutual system in experimental teaching not only enhances students practical skills in laboratory operations but also increases classroom efficiency.Furthermore,it supports personalized development among students while fostering innovative thinking,independent learning capabilities,and analysis and problem-solving skills.Additionally,this approach contributes to the enhancement of students scientific literacy.
基金Supported by Ministry of Science and Technology of China“National Project of Science and Technology for Food Production”(2004ba520a04)~~
文摘[Objective] Study on the effects of rice-duck mutualism on weeds and insects pests and economic benefits of paddy field. [Method] Comparison of the incidence of weeds, sheath blight and insects pest under rice-duck mutualism, conventional cultivation and control treatment, the yield and economic benefits were analyzed under the 3 treatments. [Result] Average occurrence of weeds in rice-duck mutualism group decreased by 2.33 and 52.0g ind/m^2 compared with that in conventional cultivation and control treatment ; the control rate of mutualism was up to 75% against rice hopper, but just between 25% -60% against rice leaf roller and Chilo suppressalis. The rates of diseased plant and diseased bell against rice sheath blight were higher and disease indices were lower compared with control group. The yield of mutualism group was identical with conventional cultivation, Which was greatly higher than that of control group. The results suggested an higher economic benefits and lower cost benefit ratio for rice-duck mutualism treatment. [Conclusion] Rice-duck mutualism gives birth to a positive effect to control the diseases, insect pests and weeds, as well as to economic benefits, providing basis on extension of rice-duck mutualism system.
文摘On the threshold of 55 years of diplomatic relations,Cyprus and China stand to gain significantly by deepening their cooperation in trade,tourism,and green technology,guided by mutual respect and shared principles.WITH a population of approximately one million,Cyprus is a small country compared to China,which is home to more than 1.4 billion people.
文摘The year 2025 marks both the 25th anniversary of the Forum on China-Africa Cooperation(FOCAC)and the first year of implementation of the outcomes of the 2024 FOCAC Beijing Summit.Throughout the year,China has supported Africa in addressing historical injustices at diplomatic and political levels and firmly backed South Africa in hosting the G20 Leaders’Summit,further deepening China-Africa strategic mutual trust.
基金supported by National Natural Science Foundation of China(No.61571061)
文摘In this paper, we focus on the design of irregular QC-LDPC code based multi-level coded modulation(MLCM) scheme by jointly optimizing the component code rate and the degree distribution of the irregular QC-LDPC component code. Firstly, the sub-channel capacities of MLCM systems is analyzed and discussed, based on which the optimal component code rate can be obtained. Secondly, an extrinsic information transfer chart based two-stage searching algorithm is proposed to find the good irregular QC-LDPC code ensembles with optimal component code rates for their corresponding sub-channels. Finally, by constructing the irregular QC-LDPC component codes from the designed ensembles with the aim of possibly enlarging the girth and reducing the number of the shortest cycles, the designed irregular QC-LDPC code based 16QAM and 64QAM MLCM systems can achieve 0.4 dB and 1.2 dB net coding gain, respectively, compared with the recently proposed regular QC-LDPC code based 16QAM and 64QAM MLCM systems.
文摘With the availability of low-cost radio frequency identification (RFID) tags,security becomes an increasing concern. However,such tags do not permit complex cryptographic functions due to their computational,communications,and storage limitations. In this paper,we investigate the security issues and requirements of RFID systems,and propose ultra-light weight and light weight protocols for low-cost RFID tags.The proposed protocols has been applied to a supply chain management system.
基金supported in part by the European Commission Marie Curie IRSES project "AdvIOT"the National Natural Science Foundation of China (NSFC) under grant No.61372103
文摘In network-connected UAV(NCUAV) communication systems, user authentication is replaced by platform identity authentication and integrity check because many NC-UAVs are operated without human intervention. Direct anonymous attestation(DAA) is an attractive cryptographic scheme that provides an elegant balance between platform authentication and anonymity. However, because of the low-level computing capability and limited transmission bandwidth in UAV, the existing DAA schemes are not suitable for NC-UAV communication systems. In this paper, we propose an enhanced DAA scheme with mutual authentication(MA-DAA scheme), which meets the security requirements of NC-UAV communication systems. The proposed MA-DAA scheme, which is based on asymmetric pairings, bundles the identities of trusted platform module(TPM) and Host to solve the malicious module changing attacks. Credential randomization, batch proof and verification, and mutual authentication are realized in the MA-DAA scheme. The computational workload in TPM and Host is reduced in order to meet the low computation and resource requirements in TPM and Host.The entire scheme and protocols are presented,and the security and efficiency of the proposed MA-DAA scheme are proved and analyzed.Our experiment results also confirm the high efficiency of the proposed scheme.
基金the National Key Re-search and Development Program of China(No.2020YFB1807500)the National Natural Science Foundation of China(No.62102297,No.61902292)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110496)the Fundamen-tal Research Funds for the Central Universities(No.XJS210105,No.XJS201502)the Open Project of Shaanxi Key Laboratory of Information Communi-cation Network and Security(No.ICNS202005).
文摘Blockchain and multi-access edge com-puting(MEC)are two emerging promising tech-nologies that have received extensive attention from academia and industry.As a brand-new information storage,dissemination and management mechanism,blockchain technology achieves the reliable transmis-sion of data and value.While as a new computing paradigm,multi-access edge computing enables the high-frequency interaction and real-time transmission of data.The integration of communication and com-puting in blockchain-enabled multi-access edge com-puting networks has been studied without a systemat-ical view.In the survey,we focus on the integration of communication and computing,explores the mu-tual empowerment and mutual promotion effects be-tween the blockchain and MEC,and introduces the resource integration architecture of blockchain and multi-access edge computing.Then,the paper sum-marizes the applications of the resource integration ar-chitecture,resource management,data sharing,incen-tive mechanism,and consensus mechanism,and ana-lyzes corresponding applications in real-world scenar-ios.Finally,future challenges and potentially promis-ing research directions are discussed and present in de-tail.
文摘Strong inductive coupling between the heating field and equilibrium field is confirmed to be responsible for the poor plasma equilibrium in initial discharges on the SUNIST spherical tokamak. A modification project for the power supply system of equilibrium field coils is successfully performed to increase the duration time of plasma current flattop from much less than 1ms to about 2 ms.
基金Under the auspices of the Science Data Sharing Pilot Project of Ministry of Science and Technology of China (No. 2003DEA2C010), Natural Science Fund of Henan University on Virtual City Construction Method (No. 04YBRW026)
文摘Virtual Reality provides a new approach for geographical research. In this paper, a framework of the Virtual Huanghe （Yellow） River System was first presented from the view of technology, which included five main modules——data sources, 3D simulation terrain database, 3D simulation model database, 3D simulation implementation and application system. Then the key technoiogies of constructing Virtual Huanghe River System were discussed in detail： 1） OpenGL technology, the 3D graphics developing instrument, was employed in Virtual Huanghe River System to realize the function of dynamic real-time navigation. 2） MO and OpenGL technologies were used to make the mutual response between 3D scene and 2D electronic map available, which made use of the advantages of both 3D scene and 2D electronic map, with the macroscopic view, integrality and conciseness of 2D electronic map combined with the locality, reality and visualization of 3D scene. At the same time the disadvantages of abstract and ambiguity of 2D electronic map and the direction losing of virtual navigation in 3D scene were overcome.
文摘In this paper, we focus on the power allocation of Integrated Sensing and Communication(ISAC) with orthogonal frequency division multiplexing(OFDM) waveform. In order to improve the spectrum utilization efficiency in ISAC, we propose a design scheme based on spectrum sharing, that is,to maximize the mutual information(MI) of radar sensing while ensuring certain communication rate and transmission power constraints. In the proposed scheme, three cases are considered for the scattering off the target due to the communication signals,as negligible signal, beneficial signal, and interference signal to radar sensing, respectively, thus requiring three power allocation schemes. However,the corresponding power allocation schemes are nonconvex and their closed-form solutions are unavailable as a consequence. Motivated by this, alternating optimization(AO), sequence convex programming(SCP) and Lagrange multiplier are individually combined for three suboptimal solutions corresponding with three power allocation schemes. By combining the three algorithms, we transform the non-convex problem which is difficult to deal with into a convex problem which is easy to solve and obtain the suboptimal solution of the corresponding optimization problem. Numerical results show that, compared with the allocation results of the existing algorithms, the proposed joint design algorithm significantly improves the radar performance.
文摘In this paper, the temporal and spatial patterns of a diffusive predator-prey model with mutual interference under homogeneous Neumann boundary conditions were studied. Specifically, first, taking the intrinsic growth rate of the predator as the parameter, we give a computational and theoretical analysis of Hopf bifurcation on the positive equilibrium for the ODE system. As well, we have discussed the conditions for determining the bifurcation direction and the stability of the bifurcating periodic solutions.
文摘Asia is the major producing area of aquatic products.In order to maintain the stability of fishery,some Asian countries have established a mutual insurance system,which,however,shows distinctive features in different countries as a result of their different historical,economic and social conditions.This paper introduced the development status and characteristics of the fishery mutual insurance system in some Asian countries,such as Japan,South Korea,India,etc.,and then summarized their experiences and what we can learn from their experiences from the perspectives of legislation,governmental support,mutual insurance associations,and credit.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61331007,61361166008,and 61401065)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20120185130001)
文摘Utilizing channel reciprocity, time reversal（TR） technique increases the signal-to-noise ratio（SNR） at the receiver with very low transmitter complexity in complex multipath environment. Present research works about TR multiple-input multiple-output（MIMO） communication all focus on the system implementation and network building. The aim of this work is to analyze the influence of antenna coupling on the capacity of wideband TR MIMO system, which is a realistic question in designing a practical communication system. It turns out that antenna coupling stabilizes the capacity in a small variation range with statistical wideband channel response. Meanwhile, antenna coupling only causes a slight detriment to the channel capacity in a wideband TR MIMO system. Comparatively, uncorrelated stochastic channels without coupling exhibit a wider range of random capacity distribution which greatly depends on the statistical channel. The conclusions drawn from information difference entropy theory provide a guideline for designing better high-performance wideband TR MIMO communication systems.
基金supported by National Natural Science Foundation of China,Nos.61822505,11774101,61627827Science and Technology Planning Project of Guangdong Province,No.2015B020233016+2 种基金China Postdoctoral Science Foundation,No.2019 M652943Natural Science Foundation of Guangdong Province,No.2019A1515011399Guangzhou Science and Technology Program key projects,Nos.2019050001.
文摘A micro-electromechanical system(MEMS)scanning mirror accelerates the raster scanning of optical-resolution photoacoustic microscopy(OR-PAM).However,the nonlinear tilt angular-voltage characteristic of a MEMS mirror introduces distortion into the maximum back-projection image.Moreover,the size of the airy disk,ultrasonic sensor properties,and thermal effects decrease the resolution.Thus,in this study,we proposed a spatial weight matrix(SWM)with a dimensionality reduction for image reconstruction.The three-layer SWM contains the invariable information of the system,which includes a spatial dependent distortion correction and 3D deconvolution.We employed an ordinal-valued Markov random field and the Harris Stephen algorithm,as well as a modified delay-and-sum method during a time reversal.The results from the experiments and a quantitative analysis demonstrate that images can be effectively reconstructed using an SWM;this is also true for severely distorted images.The index of the mutual information between the reference images and registered images was 70.33 times higher than the initial index,on average.Moreover,the peak signal-to-noise ratio was increased by 17.08%after 3D deconvolution.This accomplishment offers a practical approach to image reconstruction and a promising method to achieve a real-time distortion correction for MEMS-based OR-PAM.
基金the Deanship of Graduate Studies at Jouf University for funding and supporting this research through the initiative of DGS,Graduate Students Research Support(GSR)at Jouf University,Saudi Arabia.
文摘Wireless medical sensor networks(WMSNs)play a significant role in increasing the availability of remote healthcare systems.The vital and physiological data of the patient can be collected using the WMSN via sensor nodes that are placed on his/her body and then transmitted remotely to a healthcare professional for proper diagnosis.The protection of the patient’s privacy and their data from unauthorized access is a major concern in such systems.Therefore,an authentication scheme with a high level of security is one of the most effective mechanisms by which to address these security concerns.Many authentication schemes for remote patient monitoring have been proposed recently.However,the majority of these schemes are extremely vulnerable to attacks and are unsuitable for practical use.This paper proposes a secure three-factor authentication scheme for a patient-monitoring healthcare system that operates remotely using a WMSN.The proposed authentication scheme is formally verified using the Burrows,Abadi and Needham’s(BAN)logic model and an automatic cryptographic protocol verifier(ProVerif)tool.We show that our authentication scheme can prevent relevant types of security breaches in a practical context according to the discussed possible attack scenarios.Comparisons of the security and performance are carried out with recently proposed authentication schemes.The results of the analysis show that the proposed authentication scheme is secure and practical for use,with reasonable storage space,computation,and communication efficiency.
