In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrali...In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrality) of a vertex is related to the ability of the network to respond to the deactivation or removal of that vertex from the network. In particular, the Laplacian centrality of a vertex is defined as the relative drop of Laplacian energy caused by the deactivation of this vertex. The Laplacian energy of network G with?n?vertices is defined as , where ?is the eigenvalue of the Laplacian matrix of G. Other dynamics based measures such as that of Masuda and Kori and PageRank compute the importance of a node by analyzing the way paths pass through a node while our measure captures this information as well as the way these paths are “redistributed” when the node is deleted. The validity and robustness of this new measure are illustrated on two different terrorist social network data sets and 84 networks in James Moody’s Add Health in school friendship nomination data, and is compared with other standard centrality measures.展开更多
Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of...Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of the absorp- tion and scattering on the transmittance of underwater quantum channel and the maximum secure transmission distance are studied. Considering the roughness of the sea surface, we simulate the performance bounds of CV QKD with different wind speeds using the Monte Carlo method. The results show that even if the secret key rate gradually reduces as the wind speed increases, the maximum transmission distance will not be affected obviously. Compared to the works regarding short-distance underwater optical communication, our research represents a significant step towards establishing secure communication between air platform and submarine vehicle.展开更多
This paper is concerned with a control problem of a diffusion process with the help of static mesh sensor networks in a certain region of interest and a team of networked mobile actuators carrying chemical neutralizer...This paper is concerned with a control problem of a diffusion process with the help of static mesh sensor networks in a certain region of interest and a team of networked mobile actuators carrying chemical neutralizers.The major contribution of this paper can be divided into three parts:the first is the construction of a cyber-physical system framework based on centroidal Voronoi tessellations(CVTs),the second is the convergence analysis of the actuators location,and the last is a novel proportional integral(PI)control method for actuator motion planning and neutralizing control(e.g.,spraying)of a diffusion process with a moving or static pollution source,which is more effective than a proportional(P)control method.An optimal spraying control cost function is constructed.Then,the minimization problem of the spraying amount is addressed.Moreover,a new CVT algorithm based on the novel PI control method,henceforth called PI-CVT algorithm,is introduced together with the convergence analysis of the actuators location via a PI control law.Finally,a modified simulation platform called diffusion-mobile-actuators-sensors-2-dimension-proportional integral derivative(Diff-MAS2D-PID)is illustrated.In addition,a numerical simulation example for the diffusion process is presented to verify the effectiveness of our proposed controllers.展开更多
This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to be...This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to better reflect the reality in the sensor network.To improve the estimation performance for the spatially distributed process,a network of sensors which are allowed to move within the spatial domain is used.We aim to design an estimator which is used to approximate the distributed process and the mobile trajectories for sensors such that,for all possible missing measurements,the estimation error system is globally asymptotically stable in the mean square sense.By constructing Lyapunov functionals and using inequality analysis,the guidance scheme of every sensor and the convergence of the estimation error system are obtained.Finally,a numerical example is given to verify the effectiveness of the proposed estimator utilizing the proposed guidance scheme for sensors.展开更多
The multirate multi-input systems have different updating periods and sampling periods such that the conventional identification algorithms cannot be used to identify such multirate systems. By using the auxiliary mod...The multirate multi-input systems have different updating periods and sampling periods such that the conventional identification algorithms cannot be used to identify such multirate systems. By using the auxiliary model identification idea, the multiinnovation stochastic gradient algorithm is developed to estimate the parameters of multirate systems. Finally, an illustrative example is given to verify the effectiveness of the proposed algorithm.展开更多
The topology control is an effective approach which can improve the quality of wireless sensor network at all sides. Through studying the mechanism of sensor network data transmission, the nature of data transmission ...The topology control is an effective approach which can improve the quality of wireless sensor network at all sides. Through studying the mechanism of sensor network data transmission, the nature of data transmission in wireless sensor network is concluded as a kind of responsibility transmission. By redefining the responsibility and availability of nodes, the strategy for cluster head selection is studied, the responsibility and availability is determined by the combination of the residual energy, location and current flow of nodes. Based on the above, new clustering network topology control algorithm based on responsibility transmission CNTCABRT and hierarchical multi-hop CNTCABRT is presented in this paper, whose algorithm structure is along the famous LEACH algorithm. Experimental result demonstrates its promising performance over the famous LEACH algorithm in the cluster head selection, the size of cluster, the deployment of nodes and the lifetime of nodes, and several innovative conclusions are proposed finally.展开更多
In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the...In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the stabilization of planar underactuated manipulators without gravity is a great challenge since the system includes a second order nonholonomic constraint and most classical control methods are not suitable for this kind of system.Furthermore,the complexity of the truss-like structure results in tremendous difficulty of computational complicacy and high nonlinearity during dynamic modelling in addition to controller design.It is paramount to solve these difficulties for UCTM's future applications.To solve the above difficulties,this paper presents a dynamic modelling method for UCTM and a trajectory tracking control method based on partial feedback linearization(PFL)that fulfills the control goal of moving UCTM from its original position to a desired position by tracking a given trajectory of the joint angles.To achieve this,a model equivalent method is proposed to make UCTM equivalent with a three-link manipulator in the sense of dynamic behavior.Then the Lagrangian equation combined with complex vector method is proposed in the dynamic modelling process of UCTM,which simplifies the derivation procedure.Based on the established dynamic model,a coordinate transformation method is proposed to transform the control force matrix into the conventional form of an underactuated system,so that the control force can be separated from the unactuated term.The PFL method in combination with the LQR control method is then proposed to realize the targets that the joint angles can track given desired trajectory.Simulation experiments are conducted to verify the correctness and effectiveness of the proposed methods.展开更多
Medical image fusion plays an important role in clinical applications such as image-guided surgery, image-guided radiotherapy, noninvasive diagnosis, and treatment planning. In order to retain useful information and g...Medical image fusion plays an important role in clinical applications such as image-guided surgery, image-guided radiotherapy, noninvasive diagnosis, and treatment planning. In order to retain useful information and get more reliable results, a novel medical image fusion algorithm based on pulse coupled neural networks (PCNN) and multi-feature fuzzy clustering is proposed, which makes use of the multi-feature of image and combines the advantages of the local entropy and variance of local entropy based PCNN. The results of experiments indicate that the proposed image fusion method can better preserve the image details and robustness and significantly improve the image visual effect than the other fusion methods with less information distortion.展开更多
This paper investigates the synchronization problem for two different complex dynamical Lurie networks, The first one is with constant coupling and the second one is with constant coupling and discrete-delay coupling....This paper investigates the synchronization problem for two different complex dynamical Lurie networks, The first one is with constant coupling and the second one is with constant coupling and discrete-delay coupling. Based on contraction theory and matrix measure properties, some new delay-independent synchronization conditions depending on coupling strength and network topology are proposed. Finally, simulation results are presented to support the theoretical results.展开更多
Based on the geometrical optics approximation, we analyze the effects of non-Kolmogorov turbulence on the spiral spectrum of the orbital angular momentum （OAM） of Airy-Schell beams. Our numerical results of Airy-Sch...Based on the geometrical optics approximation, we analyze the effects of non-Kolmogorov turbulence on the spiral spectrum of the orbital angular momentum （OAM） of Airy-Schell beams. Our numerical results of Airy-Schell beams on the horizontal path show that the beam spreading due to diffraction is smaller for shorter wavelengths, a smaller OAM quantum number, a larger radius of the main ring, and a higher arbitrary trans- verse scale in weak turbulence. The oscillation frequency of the mode probability density of Airy-Schell beams in the radial direction is much lower than that of Hankel-Bessel beams. The mode probability densities of Airy-Schell and HankM-Bessel beams are remarkably dependent on the wavelength and OAM quantum num- ber. In order to improve the mode probability density, Airy-Schell beams with shorter wavelengths and lower OAM quantum numbers may be the better choice, which is diametrically opposite to Hankel-Bessel beams. Our research provides a reasonable basis for selecting light sources and precise tracking.展开更多
Vegetable freshness is very important for both restaurant and home consumers.In market,sellers frequently apply water to leafy vegetables to make them not lose weight and look fresh;however,these vegetables may not be...Vegetable freshness is very important for both restaurant and home consumers.In market,sellers frequently apply water to leafy vegetables to make them not lose weight and look fresh;however,these vegetables may not be stored for a long time as they appear.After a time limit,they may be quickly rotten.It is thus meaningful to investigate early and simple detection tools to measure leafy vegetable freshness while they are frequently applied water in selling.In this work,three types of newly harvested leafy vegetables were bought from a local farmer market and stored in the air with room temperature and roots submerging in water.Chlorophyll a fluorescence(ChlF)from the vegetables was measured each half a day for three days.The obtained ChlF data were analyzed statistically and the correlation of ChlF parameters and vegetable freshness/storage time was obtained.The k-mean classification was also performed.It is found that Fo,Fj,Fm/Fo,and Fv/Fm can be used as an early detection tool to differentiate the freshness of leafy vegetables on which water is constantly applied in storage without visible difference.展开更多
Non-thermal effects of direct electric fields and alternating electromagnetic fields(EMF)have been successfully used in a number of studies and applications in agriculture and biotechnology.Among different kinds of hi...Non-thermal effects of direct electric fields and alternating electromagnetic fields(EMF)have been successfully used in a number of studies and applications in agriculture and biotechnology.Among different kinds of high strength EMF generators,the Tesla transformer(TT)is known as a widely applied,low cost,and troubleproof device,which generates EMF in the range of 2-8 MHz.Despite of a number of developed and perspective applications of high strength EMFs in agriculture and biotechnology,the EMFs generated by TT,as well as the 1-50 MHz range of high strength EMF still remain unexplored in the fields of plant physiology,ultrastructure studies and biochemistry.In this work,we have shown that TT-EMFs(4 MHz)induced fast stem and petiole bending,disappearance of cell organelles,vacuolar membranes,and increase of a non-photochemical chlorophyll fluorescence quenching in petioles.It is intriguing that such fatal effects can be evoked in plants by EMFs which are well known as harmless for man at the applied strength and frequency.展开更多
We propose and experimentally demonstrate a photonic approach to estimate the time-difference-of-arrival （TDOA） and the angle-of-arrival （AOA） of a microwave signal. TDOA and AOA are estimated from the carrier pow...We propose and experimentally demonstrate a photonic approach to estimate the time-difference-of-arrival （TDOA） and the angle-of-arrival （AOA） of a microwave signal. TDOA and AOA are estimated from the carrier power difference of the two outputs of the Mach-Zehnder modulator （MZM） using only one dual- drive 1×2 MZM. Experimentally, the TDOA of a microwave signal at 3 GHz from 27.78 to 166.67 ps is measured with maximum measurement errors of ±2.24 ps; correspondingly, the AOA from 60° to 85.2° is measured with maximum measurement errors of ±0.4°.展开更多
Maximal and partial quantum yields of photosystem II(Fv/Fm and Fv–/Fp)in Phaseolus vulgaris leaves were determined in response to the turning on saturating and low(undersaturating)actinic light,accordingly.Measuring ...Maximal and partial quantum yields of photosystem II(Fv/Fm and Fv–/Fp)in Phaseolus vulgaris leaves were determined in response to the turning on saturating and low(undersaturating)actinic light,accordingly.Measuring lights(ML)of blue,green,and red colors were applied simultaneously using a novel method of the polychromatic fast Fourier transforming pulse amplitude modulation(FFT PAM)chlorophyll fluorometry.Colors of ML were cross-combined with the colors of low and saturating actinic light.Fv/Fm values measured with the green ML were found to be close to that of red light,whereas application of blue ML leads to lower Fv/Fm.In addition,5-nm resolved excitation spectra were measured to evaluate the dependence between red/far red fluorescence ratios(peak height based–F685/F730,and deconvolved peak square based–F685sq/F730sq)and wavelength of the excitation light.It demonstrates that chlorophyll fluorescence ratio red/far red may be dependent on the spectral absorbance of chlorophyll.The data obtained confirm the results of the previous studies which explain high photosynthetic activity of the green light in terms of redistribution of absorbed quanta throughout thickness of the leaf,thus suggesting possible advisability of green light application in greenhouse lighting,especially for the plants having thick leaves.展开更多
For dynamic application scenarios of Mobile Edge Computing(MEC),an Energy-efficient Multiuser and Multitask Computation Offloading(EMMCO)optimization method is proposed.Under the consideration of multiuser and multita...For dynamic application scenarios of Mobile Edge Computing(MEC),an Energy-efficient Multiuser and Multitask Computation Offloading(EMMCO)optimization method is proposed.Under the consideration of multiuser and multitask computation offloading,first,the EMMCO method takes into account the existence of dependencies among different tasks within an implementation,abstracts these dependencies as a Directed Acyclic Graph(DAG),and models the computation offloading problem as a Markov decision process.Subsequently,the task embedding sequence in the DAG is fed to the RNN encoder-decoder neural network with combination of the attention mechanism,the long-term dependencies among different tasks are successfully captured by this scheme.Finally,the Improved Policy Loss Clip-based PPO2(IPLC-PPO2)algorithm is developed,and the RNN encoder-decoder neural network is trained by the developed algorithm.The loss function in the IPLC-PPO2 algorithm is utilized as a preference for the training process,and the neural network parameters are continuously updated to select the optimal offloading scheduling decisions.Simulation results demonstrate that the proposed EMMCO method can achieve lower latency,reduce energy consumption,and obtain a significant improvement in the Quality of Service(QoS)than the compared algorithms under different situations of mobile edge network.展开更多
To efficiently mine threat intelligence from the vast array of open-source cybersecurity analysis reports on the web,we have developed the Parallel Deep Forest-based Multi-Label Classification(PDFMLC)algorithm.Initial...To efficiently mine threat intelligence from the vast array of open-source cybersecurity analysis reports on the web,we have developed the Parallel Deep Forest-based Multi-Label Classification(PDFMLC)algorithm.Initially,open-source cybersecurity analysis reports are collected and converted into a standardized text format.Subsequently,five tactics category labels are annotated,creating a multi-label dataset for tactics classification.Addressing the limitations of low execution efficiency and scalability in the sequential deep forest algorithm,our PDFMLC algorithm employs broadcast variables and the Lempel-Ziv-Welch(LZW)algorithm,significantly enhancing its acceleration ratio.Furthermore,our proposed PDFMLC algorithm incorporates label mutual information from the established dataset as input features.This captures latent label associations,significantly improving classification accuracy.Finally,we present the PDFMLC-based Threat Intelligence Mining(PDFMLC-TIM)method.Experimental results demonstrate that the PDFMLC algorithm exhibits exceptional node scalability and execution efficiency.Simultaneously,the PDFMLC-TIM method proficiently conducts text classification on cybersecurity analysis reports,extracting tactics entities to construct comprehensive threat intelligence.As a result,successfully formatted STIX2.1 threat intelligence is established.展开更多
Broadband light detection and sensing are widely applied in modern technology.As a promising candidate for next-generation two-dimensional(2D)optoelectronic material,bismuth oxyselenide(Bi_(2)O_(2)Se)nanoplates exhibi...Broadband light detection and sensing are widely applied in modern technology.As a promising candidate for next-generation two-dimensional(2D)optoelectronic material,bismuth oxyselenide(Bi_(2)O_(2)Se)nanoplates exhibit many prospects in the application of visible light detection due to their peculiar properties.In this work,we report the photodetection performance of single-crystal 2D Bi_(2)O_(2)Se nanoplates grown on SiO_(2)based on a ternary-alloy growth model by utilizing chemical vapor deposition(CVD).The Bi_(2)O_(2)Se nanoplates were found to have an even and uniform square shape with side lengths up to 15μm and an approximate thickness of 15 nm.A visible-light photodetector was fabricated based on a CVD-grown Bi_(2)O_(2)Se nanoplate,and characterized by a set of illumination experiments using a 400 nm laser at temperatures ranging from 77 to 370 K.The device exhibited superior performance at the temperature of 77 K,with a responsivity of 523 A/W,a specific detectivity of 1.37×10^(11)Jones,a response time of 0.2175 ms,an external quantum efficiency of 162,119.44%,resulting in high-quality and fullcolor imaging in the visible spectrum.These results indicate that the single-crystalline Bi_(2)O_(2)Se nanoplates have excellent potential in broadband photodetection and non-cryogenic imaging.展开更多
文摘In this work we propose a centrality measure for networks, which we refer to as Laplacian centrality, that provides a general framework for the centrality of a vertex based on the idea that the importance (or centrality) of a vertex is related to the ability of the network to respond to the deactivation or removal of that vertex from the network. In particular, the Laplacian centrality of a vertex is defined as the relative drop of Laplacian energy caused by the deactivation of this vertex. The Laplacian energy of network G with?n?vertices is defined as , where ?is the eigenvalue of the Laplacian matrix of G. Other dynamics based measures such as that of Masuda and Kori and PageRank compute the importance of a node by analyzing the way paths pass through a node while our measure captures this information as well as the way these paths are “redistributed” when the node is deleted. The validity and robustness of this new measure are illustrated on two different terrorist social network data sets and 84 networks in James Moody’s Add Health in school friendship nomination data, and is compared with other standard centrality measures.
基金Supported by the National Natural Science Foundation of China under Grant No 61572529
文摘Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of the absorp- tion and scattering on the transmittance of underwater quantum channel and the maximum secure transmission distance are studied. Considering the roughness of the sea surface, we simulate the performance bounds of CV QKD with different wind speeds using the Monte Carlo method. The results show that even if the secret key rate gradually reduces as the wind speed increases, the maximum transmission distance will not be affected obviously. Compared to the works regarding short-distance underwater optical communication, our research represents a significant step towards establishing secure communication between air platform and submarine vehicle.
基金supported by the National Natural Science Foundation of China(61473136,61807016)the Fundamental Research Funds for the Central Universities(JUSRP51322B)+1 种基金the 111 Project(B12018)Jiangsu Innovation Program for Graduates(KYLX15 1170)
文摘This paper is concerned with a control problem of a diffusion process with the help of static mesh sensor networks in a certain region of interest and a team of networked mobile actuators carrying chemical neutralizers.The major contribution of this paper can be divided into three parts:the first is the construction of a cyber-physical system framework based on centroidal Voronoi tessellations(CVTs),the second is the convergence analysis of the actuators location,and the last is a novel proportional integral(PI)control method for actuator motion planning and neutralizing control(e.g.,spraying)of a diffusion process with a moving or static pollution source,which is more effective than a proportional(P)control method.An optimal spraying control cost function is constructed.Then,the minimization problem of the spraying amount is addressed.Moreover,a new CVT algorithm based on the novel PI control method,henceforth called PI-CVT algorithm,is introduced together with the convergence analysis of the actuators location via a PI control law.Finally,a modified simulation platform called diffusion-mobile-actuators-sensors-2-dimension-proportional integral derivative(Diff-MAS2D-PID)is illustrated.In addition,a numerical simulation example for the diffusion process is presented to verify the effectiveness of our proposed controllers.
基金supported by the National Natural Science Foundation of China(Grant Nos.61174021,61473136,and 61104155)the 111 Project(Grant No.B12018)
文摘This paper investigates the estimation problem for a spatially distributed process described by a partial differential equation with missing measurements.The randomly missing measurements are introduced in order to better reflect the reality in the sensor network.To improve the estimation performance for the spatially distributed process,a network of sensors which are allowed to move within the spatial domain is used.We aim to design an estimator which is used to approximate the distributed process and the mobile trajectories for sensors such that,for all possible missing measurements,the estimation error system is globally asymptotically stable in the mean square sense.By constructing Lyapunov functionals and using inequality analysis,the guidance scheme of every sensor and the convergence of the estimation error system are obtained.Finally,a numerical example is given to verify the effectiveness of the proposed estimator utilizing the proposed guidance scheme for sensors.
基金supported by the National Natural Science Foundation of China (60973043)
文摘The multirate multi-input systems have different updating periods and sampling periods such that the conventional identification algorithms cannot be used to identify such multirate systems. By using the auxiliary model identification idea, the multiinnovation stochastic gradient algorithm is developed to estimate the parameters of multirate systems. Finally, an illustrative example is given to verify the effectiveness of the proposed algorithm.
文摘The topology control is an effective approach which can improve the quality of wireless sensor network at all sides. Through studying the mechanism of sensor network data transmission, the nature of data transmission in wireless sensor network is concluded as a kind of responsibility transmission. By redefining the responsibility and availability of nodes, the strategy for cluster head selection is studied, the responsibility and availability is determined by the combination of the residual energy, location and current flow of nodes. Based on the above, new clustering network topology control algorithm based on responsibility transmission CNTCABRT and hierarchical multi-hop CNTCABRT is presented in this paper, whose algorithm structure is along the famous LEACH algorithm. Experimental result demonstrates its promising performance over the famous LEACH algorithm in the cluster head selection, the size of cluster, the deployment of nodes and the lifetime of nodes, and several innovative conclusions are proposed finally.
基金Projects(51275107,52005124)supported by the National Natural Science Foundation of China。
文摘In recent years,an innovative underactuated robot was developed,named as underactuated cable-driven trusslike manipulator(UCTM),to be suitable in aerospace applications.However,there has been strong consensus that the stabilization of planar underactuated manipulators without gravity is a great challenge since the system includes a second order nonholonomic constraint and most classical control methods are not suitable for this kind of system.Furthermore,the complexity of the truss-like structure results in tremendous difficulty of computational complicacy and high nonlinearity during dynamic modelling in addition to controller design.It is paramount to solve these difficulties for UCTM's future applications.To solve the above difficulties,this paper presents a dynamic modelling method for UCTM and a trajectory tracking control method based on partial feedback linearization(PFL)that fulfills the control goal of moving UCTM from its original position to a desired position by tracking a given trajectory of the joint angles.To achieve this,a model equivalent method is proposed to make UCTM equivalent with a three-link manipulator in the sense of dynamic behavior.Then the Lagrangian equation combined with complex vector method is proposed in the dynamic modelling process of UCTM,which simplifies the derivation procedure.Based on the established dynamic model,a coordinate transformation method is proposed to transform the control force matrix into the conventional form of an underactuated system,so that the control force can be separated from the unactuated term.The PFL method in combination with the LQR control method is then proposed to realize the targets that the joint angles can track given desired trajectory.Simulation experiments are conducted to verify the correctness and effectiveness of the proposed methods.
文摘Medical image fusion plays an important role in clinical applications such as image-guided surgery, image-guided radiotherapy, noninvasive diagnosis, and treatment planning. In order to retain useful information and get more reliable results, a novel medical image fusion algorithm based on pulse coupled neural networks (PCNN) and multi-feature fuzzy clustering is proposed, which makes use of the multi-feature of image and combines the advantages of the local entropy and variance of local entropy based PCNN. The results of experiments indicate that the proposed image fusion method can better preserve the image details and robustness and significantly improve the image visual effect than the other fusion methods with less information distortion.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.61174021 and 61104155)the Fundamental Research Funds for the Central Universities (Grant No.JUDCF12033)+3 种基金the Jiangsu Innovation Program for Graduates (Grant No.CXZZ12 0742)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)the Fundamental Research Funds for the Central Universities (Grant No.JUSRP51322B)the 111 Project (Grant No.B12018)
文摘This paper investigates the synchronization problem for two different complex dynamical Lurie networks, The first one is with constant coupling and the second one is with constant coupling and discrete-delay coupling. Based on contraction theory and matrix measure properties, some new delay-independent synchronization conditions depending on coupling strength and network topology are proposed. Finally, simulation results are presented to support the theoretical results.
基金supported by the Fundamental Research Funds for the Central Universities of China under Grant No.1142050205135370
文摘Based on the geometrical optics approximation, we analyze the effects of non-Kolmogorov turbulence on the spiral spectrum of the orbital angular momentum （OAM） of Airy-Schell beams. Our numerical results of Airy-Schell beams on the horizontal path show that the beam spreading due to diffraction is smaller for shorter wavelengths, a smaller OAM quantum number, a larger radius of the main ring, and a higher arbitrary trans- verse scale in weak turbulence. The oscillation frequency of the mode probability density of Airy-Schell beams in the radial direction is much lower than that of Hankel-Bessel beams. The mode probability densities of Airy-Schell and HankM-Bessel beams are remarkably dependent on the wavelength and OAM quantum num- ber. In order to improve the mode probability density, Airy-Schell beams with shorter wavelengths and lower OAM quantum numbers may be the better choice, which is diametrically opposite to Hankel-Bessel beams. Our research provides a reasonable basis for selecting light sources and precise tracking.
文摘Vegetable freshness is very important for both restaurant and home consumers.In market,sellers frequently apply water to leafy vegetables to make them not lose weight and look fresh;however,these vegetables may not be stored for a long time as they appear.After a time limit,they may be quickly rotten.It is thus meaningful to investigate early and simple detection tools to measure leafy vegetable freshness while they are frequently applied water in selling.In this work,three types of newly harvested leafy vegetables were bought from a local farmer market and stored in the air with room temperature and roots submerging in water.Chlorophyll a fluorescence(ChlF)from the vegetables was measured each half a day for three days.The obtained ChlF data were analyzed statistically and the correlation of ChlF parameters and vegetable freshness/storage time was obtained.The k-mean classification was also performed.It is found that Fo,Fj,Fm/Fo,and Fv/Fm can be used as an early detection tool to differentiate the freshness of leafy vegetables on which water is constantly applied in storage without visible difference.
基金Southern Federal University(Rostov-on-Don)for the grant(N 213.01-07-2014/06PChVG)provided to achieve the aims of the present research.
文摘Non-thermal effects of direct electric fields and alternating electromagnetic fields(EMF)have been successfully used in a number of studies and applications in agriculture and biotechnology.Among different kinds of high strength EMF generators,the Tesla transformer(TT)is known as a widely applied,low cost,and troubleproof device,which generates EMF in the range of 2-8 MHz.Despite of a number of developed and perspective applications of high strength EMFs in agriculture and biotechnology,the EMFs generated by TT,as well as the 1-50 MHz range of high strength EMF still remain unexplored in the fields of plant physiology,ultrastructure studies and biochemistry.In this work,we have shown that TT-EMFs(4 MHz)induced fast stem and petiole bending,disappearance of cell organelles,vacuolar membranes,and increase of a non-photochemical chlorophyll fluorescence quenching in petioles.It is intriguing that such fatal effects can be evoked in plants by EMFs which are well known as harmless for man at the applied strength and frequency.
基金supported by the Program for New Century Excellent Talents in University(No.NCET-11-0659)the National 111 Project of China(No.B12018)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We propose and experimentally demonstrate a photonic approach to estimate the time-difference-of-arrival （TDOA） and the angle-of-arrival （AOA） of a microwave signal. TDOA and AOA are estimated from the carrier power difference of the two outputs of the Mach-Zehnder modulator （MZM） using only one dual- drive 1×2 MZM. Experimentally, the TDOA of a microwave signal at 3 GHz from 27.78 to 166.67 ps is measured with maximum measurement errors of ±2.24 ps; correspondingly, the AOA from 60° to 85.2° is measured with maximum measurement errors of ±0.4°.
基金We are grateful to Ministry of education and science of the Russian Federation for the financial support(grant No 6.6222.2017/8.9).The project was performed with the equipment of Multiaccess Center‘‘Biotechnology,Biomedicine and Environmental Monitoring”,Laboratory of plant ecology and physiology of Academy of Biology and Biotechnology of Southern Federal University(Rostov-on-Don).Researchers are also grateful to Russian Information-Analytical andWater Management Research Center for help in performing this study.
文摘Maximal and partial quantum yields of photosystem II(Fv/Fm and Fv–/Fp)in Phaseolus vulgaris leaves were determined in response to the turning on saturating and low(undersaturating)actinic light,accordingly.Measuring lights(ML)of blue,green,and red colors were applied simultaneously using a novel method of the polychromatic fast Fourier transforming pulse amplitude modulation(FFT PAM)chlorophyll fluorometry.Colors of ML were cross-combined with the colors of low and saturating actinic light.Fv/Fm values measured with the green ML were found to be close to that of red light,whereas application of blue ML leads to lower Fv/Fm.In addition,5-nm resolved excitation spectra were measured to evaluate the dependence between red/far red fluorescence ratios(peak height based–F685/F730,and deconvolved peak square based–F685sq/F730sq)and wavelength of the excitation light.It demonstrates that chlorophyll fluorescence ratio red/far red may be dependent on the spectral absorbance of chlorophyll.The data obtained confirm the results of the previous studies which explain high photosynthetic activity of the green light in terms of redistribution of absorbed quanta throughout thickness of the leaf,thus suggesting possible advisability of green light application in greenhouse lighting,especially for the plants having thick leaves.
基金supported by the Smart Manufacturing New Model Application Project Ministry of Industry and Information Technology(No.ZH-XZ-18004)the Future Research Projects Funds for the Science and Technology Department of Jiangsu Province(No.BY2013015-23)+2 种基金the Fundamental Research Funds for the Ministry of Education(No.JUSRP211A 41)the Fundamental Research Funds for the Central Universities(No.JUSRP42003)the 111 Project(No.B2018).
文摘For dynamic application scenarios of Mobile Edge Computing(MEC),an Energy-efficient Multiuser and Multitask Computation Offloading(EMMCO)optimization method is proposed.Under the consideration of multiuser and multitask computation offloading,first,the EMMCO method takes into account the existence of dependencies among different tasks within an implementation,abstracts these dependencies as a Directed Acyclic Graph(DAG),and models the computation offloading problem as a Markov decision process.Subsequently,the task embedding sequence in the DAG is fed to the RNN encoder-decoder neural network with combination of the attention mechanism,the long-term dependencies among different tasks are successfully captured by this scheme.Finally,the Improved Policy Loss Clip-based PPO2(IPLC-PPO2)algorithm is developed,and the RNN encoder-decoder neural network is trained by the developed algorithm.The loss function in the IPLC-PPO2 algorithm is utilized as a preference for the training process,and the neural network parameters are continuously updated to select the optimal offloading scheduling decisions.Simulation results demonstrate that the proposed EMMCO method can achieve lower latency,reduce energy consumption,and obtain a significant improvement in the Quality of Service(QoS)than the compared algorithms under different situations of mobile edge network.
文摘To efficiently mine threat intelligence from the vast array of open-source cybersecurity analysis reports on the web,we have developed the Parallel Deep Forest-based Multi-Label Classification(PDFMLC)algorithm.Initially,open-source cybersecurity analysis reports are collected and converted into a standardized text format.Subsequently,five tactics category labels are annotated,creating a multi-label dataset for tactics classification.Addressing the limitations of low execution efficiency and scalability in the sequential deep forest algorithm,our PDFMLC algorithm employs broadcast variables and the Lempel-Ziv-Welch(LZW)algorithm,significantly enhancing its acceleration ratio.Furthermore,our proposed PDFMLC algorithm incorporates label mutual information from the established dataset as input features.This captures latent label associations,significantly improving classification accuracy.Finally,we present the PDFMLC-based Threat Intelligence Mining(PDFMLC-TIM)method.Experimental results demonstrate that the PDFMLC algorithm exhibits exceptional node scalability and execution efficiency.Simultaneously,the PDFMLC-TIM method proficiently conducts text classification on cybersecurity analysis reports,extracting tactics entities to construct comprehensive threat intelligence.As a result,successfully formatted STIX2.1 threat intelligence is established.
基金the support of the Australian Research Council(Nos.DP200103188,LE200100032,DP170104562,LP170100088,FT130101708,and LE170100233)Universities Australia-DAAD German Research cooperation scheme(2014-2015)the Centre for Microscopy,Characterization and Analysis(CMCA)at UWA.
文摘Broadband light detection and sensing are widely applied in modern technology.As a promising candidate for next-generation two-dimensional(2D)optoelectronic material,bismuth oxyselenide(Bi_(2)O_(2)Se)nanoplates exhibit many prospects in the application of visible light detection due to their peculiar properties.In this work,we report the photodetection performance of single-crystal 2D Bi_(2)O_(2)Se nanoplates grown on SiO_(2)based on a ternary-alloy growth model by utilizing chemical vapor deposition(CVD).The Bi_(2)O_(2)Se nanoplates were found to have an even and uniform square shape with side lengths up to 15μm and an approximate thickness of 15 nm.A visible-light photodetector was fabricated based on a CVD-grown Bi_(2)O_(2)Se nanoplate,and characterized by a set of illumination experiments using a 400 nm laser at temperatures ranging from 77 to 370 K.The device exhibited superior performance at the temperature of 77 K,with a responsivity of 523 A/W,a specific detectivity of 1.37×10^(11)Jones,a response time of 0.2175 ms,an external quantum efficiency of 162,119.44%,resulting in high-quality and fullcolor imaging in the visible spectrum.These results indicate that the single-crystalline Bi_(2)O_(2)Se nanoplates have excellent potential in broadband photodetection and non-cryogenic imaging.
