Dear Editor,This letter addresses the challenge of achieving robust global coordination in multi-agent systems(MASs)subject to heterogeneous actuator saturation and additive input disturbances.We develop a novel distr...Dear Editor,This letter addresses the challenge of achieving robust global coordination in multi-agent systems(MASs)subject to heterogeneous actuator saturation and additive input disturbances.We develop a novel distributed control framework that strategically integrates a redesigned saturation function to handle the nonlinear actuator constraint and a high-gain feedback mechanism for effective disturbance rejection.展开更多
This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in...This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design,the controllers can be used to track different time-varying target formation patterns. Besides, multilayer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results.展开更多
This paper tackles the formation-containment control problem of fixed-wing unmanned aerial vehicle(UAV)swarm with model uncertainties for dynamic target tracking in three-dimensional space in the faulty case of UAVs’...This paper tackles the formation-containment control problem of fixed-wing unmanned aerial vehicle(UAV)swarm with model uncertainties for dynamic target tracking in three-dimensional space in the faulty case of UAVs’actuator and sensor.The fixed-wing UAV swarm under consideration is organized as a“multi-leader-multi-follower”structure,in which only several leaders can obtain the dynamic target information while others only receive the neighbors’information through the communication network.To simultaneously realize the formation,containment,and dynamic target tracking,a two-layer control framework is adopted to decouple the problem into two subproblems:reference trajectory generation and trajectory tracking.In the upper layer,a distributed finite-time estimator(DFTE)is proposed to generate each UAV’s reference trajectory in accordance with the control objective.Subsequently,a distributed composite robust fault-tolerant trajectory tracking controller is developed in the lower layer,where a novel adaptive extended super-twisting(AESTW)algorithm with a finite-time extended state observer(FTESO)is involved in solving the robust trajectory tracking control problem under model uncertainties,actuator,and sensor faults.The proposed controller simultaneously guarantees rapidness and enhances the system’s robustness with fewer chattering effects.Finally,corresponding simulations are carried out to demonstrate the effectiveness and competitiveness of the proposed two-layer fault-tolerant cooperative control scheme.展开更多
A series of Tb-based metal-organic frameworks(Tb-MOFs)were successfully synthesized by a solvothermal method.The size and morphology of the as-obtained Tb-MOFs can be effectively controlled via regulating the experime...A series of Tb-based metal-organic frameworks(Tb-MOFs)were successfully synthesized by a solvothermal method.The size and morphology of the as-obtained Tb-MOFs can be effectively controlled via regulating the experimental conditions such as the volume fraction of DMF and the molar ratio of Tb^(3+)to NaOH.It is found that all the samples exhibit strong green emissions under ultraviolet excitation,corresponding to^(5)D_(4)→^(7)F_(J)transitions of Tb^(3+).Interestingly,Tb-MOFs displayed an efficient and distinct luminescence quenching by Cu^(2+)in aqueous solutions.The competitive fluorescence detection experiments indicate that these Tb-MOFs sensors can be used as a high selective and sensitive sensor of Cu^(2+)detection with the detection limit of 10μmol·L^(-1),which can be used as a promising fluorescence sensor for Cu^(2+)detection in daily life.展开更多
For the constant distance spacing policy,the existing researches of the string stability focus on the single-predecessor information framework（SPIF） and predecessor-successor information framework（PSIF）.The resear...For the constant distance spacing policy,the existing researches of the string stability focus on the single-predecessor information framework（SPIF） and predecessor-successor information framework（PSIF）.The research results demonstrated that the string stability could not be guaranteed with the SPIF,and then the PSIF was proposed to resolve this string instability.But the issue,whether the string stability can be guaranteed when applying the PSIF,is still controversial.Meanwhile,most of the previous researches on the string stability were conducted without consideration of the parasitic time delays and lags.In this paper,the practical longitudinal vehicle dynamics model is built with consideration of the parasitic time delays and lags existing in the actuators,sensors or the communication systems.Secondly,the detailed theoretical analysis of string stability in frequency domain is conducted to demonstrate that the classical linear control laws can not ensure the string stability when applying both the symmetrical PSIF（SPSIF） and asymmetrical PSIF（APSIF）.Thirdly,a control law,which adds the position and velocity information of the leading vehicle,is proposed to guarantee string stability for small/medium platoon,and the other control law,which adds the acceleration information of the controlled vehicle,is proposed to guarantee string stability for large platoon as well as small/medium platoon.Finally,the comparative simulation is conducted to confirm the conducted analysis and the proposed control laws.The conducted research completes the means to analyze the string stability in frequency domain,provides the parameters＇ reference for the design and implementation of the practical automatic following controllers,and improves the reliability and stability of the platoon of automatic vehicles.展开更多
Weighted factor is given to access eontrol policies to express the importanceof policy and its effect on access control decision. According to this weighted access controlframework, a trustworthiness model for aceess ...Weighted factor is given to access eontrol policies to express the importanceof policy and its effect on access control decision. According to this weighted access controlframework, a trustworthiness model for aceess request is also given. In this model, we give themeasure of trustworthiness factor to access request- by using some idea of uncertainty reasoning ofexpert system, present and prove the parallel propagation formula of request trustworthiness factoramong multiple policies, and get thefinal trustworthiness factor to decide whether authorizing. Inthis model, authorization decision is given according to the calculation of request trustworthinessfactor, which is more understandable, more suitable for real requirement and more powerfulforsecurity enhancement than traditional methods. Meanwhile the finer access control granularity isanother advantage.展开更多
Water-soluble three-dimensional porous supramolecular organic frameworks（SOFs） have been demonstrated as a new generation of homogeneous polycationic platforms for anti-cancer drug delivery.The new SOF drug delivery...Water-soluble three-dimensional porous supramolecular organic frameworks（SOFs） have been demonstrated as a new generation of homogeneous polycationic platforms for anti-cancer drug delivery.The new SOF drug delivery systems（sof-DDSs） can adsorb dianionic pemetrexed（PMX）,a clinically used chemotherapeutic agent instantaneously upon dissolving in water,which is driven by both electrostatic attraction and hydrophobicity.The in situ-prepared PMX@SOFs are highly stable and can avoid important release of the drug during plasm circulation and overcome the multidrug resistance of human breast MCF-7/Adr cancer cells to enter the cancer cells.Acidic microenvironment of cancer cells promotes the release of the drug in cancer cells.Both in vitro and in vivo studies have revealed that sofDDSs considerably improve the treatment efficacy of PMX,leading to 6-12-fold reduction of the IC50 values,as compared with that of PMX alone.The new drug delivery strategy omits the loading process required by most of reported nanoparticle-based delivery systems and thus holds promise for future development of low-cost drug delivery systems展开更多
Cloud computing is touted as the next big thing in the Information Technology (IT) industry, which is going to impact the businesses of any size and yet the security issue continues to pose a big threat on it. The sec...Cloud computing is touted as the next big thing in the Information Technology (IT) industry, which is going to impact the businesses of any size and yet the security issue continues to pose a big threat on it. The security and privacy issues persisting in cloud computing have proved to be an obstacle for its widespread adoption. In this paper, we look at these issues from a business perspective and how they are damaging the reputation of big companies. There is a literature review on the existing issues in cloud computing and how they are being tackled by the Cloud Service Providers (CSP). We propose a governing body framework which aims at solving these issues by establishing relationship amongst the CSPs in which the data about possible threats can be generated based on the previous attacks on other CSPs. The Governing Body will be responsible for Data Center control, Policy control, legal control, user awareness, performance evaluation, solution architecture and providing motivation for the entities involved.展开更多
The controlled self-assembly of discrete metal-organic nanocapsules(MONCs),and metal-organic frameworks(MOFs)based on the MONCs are achieved.Specifically,the solvothermal reaction of nickel nitrate hexahydrate and C-m...The controlled self-assembly of discrete metal-organic nanocapsules(MONCs),and metal-organic frameworks(MOFs)based on the MONCs are achieved.Specifically,the solvothermal reaction of nickel nitrate hexahydrate and C-methylpyrogallol[4]arene in mixed DMF/MeOH solution leads to the unexpected form of discrete nickel-seamed hexameric pyrogallol[4]arene MONCs,and MONC-based three-dimensional(3D)MOF.Notably,the latter MOF is constructed from the aforementioned nickelseamed MONC building blocks and formate linkers in-situ generated from the hydrolysis of DMF solve nt.Interestingly,introducing pyridine and formic acid in the reaction conditions leads to the controlled assemblies of the discrete MONC and MONC-based 3D MOF structures.Moreover,the variabletemperature magnetic susceptibilities of both the abovementioned compounds have been investigated,indicating typical antiferromagnetic interactions between the metal centers.展开更多
In the paper, an iterative method is presented to the optimal control of batch processes. Generally it is very difficult to acquire an accurate mechanistic model for a batch process. Because support vector machine is ...In the paper, an iterative method is presented to the optimal control of batch processes. Generally it is very difficult to acquire an accurate mechanistic model for a batch process. Because support vector machine is powerful for the problems characterized by small samples, nonlinearity, high dimension and local minima, support vector regression models are developed for the optimal control of batch processes where end-point properties are required. The model parameters are selected within the Bayesian evidence framework. Based on the model, an iterative method is used to exploit the repetitive nature of batch processes to determine the optimal operating policy. Numerical simulation shows that the iterative optimal control can improve the process performance through iterations.展开更多
Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-bas...Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.展开更多
To address the frequency fluctuation problem caused by the power dynamic imbalance between the power system and the loadwhen a large number of newenergy sources are connected to the grid,a two-layer fuzzy control stra...To address the frequency fluctuation problem caused by the power dynamic imbalance between the power system and the loadwhen a large number of newenergy sources are connected to the grid,a two-layer fuzzy control strategy is proposed for the participation of the energy storage battery system in FM.Firstly,considering the coordination of FM units responding to automatic power generation control commands,a comprehensive allocation strategy of two signals under automatic power generation control commands is proposed to give full play to the advantages of two FM signals while enabling better coordination of two FM units responding to FM commands;secondly,based on the grid FM demand and battery FM capability,a double-layer fuzzy control strategy is proposed for FM units responding to automatic power generation control commands in a coordinated manner under dual-signal allocation mode to precisely allocate the power output depth of FM units,which can control the fluctuation of frequency deviation within a smaller range at a faster speed while maintaining the battery charge state;finally,the proposed Finally,the proposed control strategy is simulated and verified inMatlab/Simulink.The results show that the proposed control strategy can control the frequency deviation within a smaller range in a shorter time,better stabilize the fluctuation of the battery charge level,and improve the utilization of the FM unit.展开更多
In view of the currant status of the quality risk control of livestock products, the differences between the quality, safety and risk of the livestock products were pointed clearly; the derivative mechanism model of t...In view of the currant status of the quality risk control of livestock products, the differences between the quality, safety and risk of the livestock products were pointed clearly; the derivative mechanism model of the quality risk was studied; the risk system of livestock products was established; and the types of controllable risk were identified. On this basis, the design principles of risk control framework were established. Then the modular system of risk control was constructed and the attributes of production system were detailed into the describable indicators of risk control based on the thrae-dimensional risks.展开更多
Aiming at the tele-operation instability caused by time delay of interuet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-roboties, which ca...Aiming at the tele-operation instability caused by time delay of interuet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-roboties, which can guarantee the non-distortion-transfer of control information and reduce the difference of action time between the local simulated virtual robot and the remote real robot. This framework is insensitive to the inherent interact time delay, and differs from other tele-robotics systems that try to use some mathematic models to describe the internet delay or take some assumptions. In order to verify the framework, a 4-DOF fischertechnik industry robot tele-operation system has been developed using the new proposed framework. Experimental results demonstrate the applicable performance of the new framework. The framework is open structured and can be applied to other general purposed tele-operation systems.展开更多
This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of ac...This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image contrast.In the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast enhancement.However,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.Therefore,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast enhancement.Since the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual quality.Any RDH method which can achieve high EC while preserve good visual quality,can be selected for the first step.In fact,Gao et al.’s method is a special case of our proposed framework.In addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework.展开更多
We proposes an AI-assisted framework for integrated natural disaster prevention and emergency response,leveraging the DeepSeek large language model(LLM)to advance intelligent decision-making in geohazard management.We...We proposes an AI-assisted framework for integrated natural disaster prevention and emergency response,leveraging the DeepSeek large language model(LLM)to advance intelligent decision-making in geohazard management.We systematically analyze the technical pathways for deploying LLMs in disaster scenarios,emphasizing three breakthrough directions:(1)knowledge graph-driven dynamic risk modeling,(2)reinforcement learning-optimized emergency decision systems,and(3)secure local deployment architectures.The DeepSeek model demonstrates unique advantages through its hybrid reasoning mechanism combining semantic analysis with geospatial pattern recognition,enabling cost-effective processing of multi-source data spanning historical disaster records,real-time IoT sensor feeds,and socio-environmental parameters.A modular system architecture is designed to achieve three critical objectives:(a)automated construction of domain-specific knowledge graphs through unsupervised learning of disaster physics relationships,(b)scenario-adaptive resource allocation using risk simulations,and(c)preserving emergency coordination via federated learning across distributed response nodes.The proposed local deployment paradigm addresses critical data security concerns in cross-border disaster management while complying with the FAIR principles(Findable,Accessible,Interoperable,Reusable)for geoscientific data governance.This work establishes a methodological foundation for next-generation AI-earth science convergence in disaster mitigation.展开更多
Metal-organic frameworks(MOFs)represent a class of multifunctional hybrid materials distinguished by their tunable structural architectures,adjustable pore dimensions,and tailorable surface chemical functionalities,wh...Metal-organic frameworks(MOFs)represent a class of multifunctional hybrid materials distinguished by their tunable structural architectures,adjustable pore dimensions,and tailorable surface chemical functionalities,which underpin their broad applicability across diverse domains.Within the cosmetics industry,MOFs exhibit significant application potential owing to their high thermal and chemical stability,substantial loading capacity,low biological toxicity,favorable luminescent characteristics,and robust catalytic activity,leading to their increasing deployment in various cosmetic-related applications.This article systematically outlines the structural features and functional properties of MOFs,emphasizing their suitability for integration into cosmetic systems.Furthermore,it provides a comprehensive review of recent advances in the utilization of MOFs in cosmetics,encompassing the detection of organic contaminants and metal ions,ultraviolet protection,encapsulation,and controlled release of volatile active ingredients,as well as targeted delivery of dermatological therapeutic agents.The structure-property-application relationships of MOFs are critically examined.Building upon the foundation of existing research,this study offers a comprehensive outlook on the future development of MOFs in the field of cosmetics.It presents several strategic perspectives,including an in-depth analysis of current application studies,the expansion of MOFs applications into additional cosmetic domains,the integration of multifunctional MOFs systems,the development of MOFs-based composite materials,and the scale-up of synthesis processes from laboratory-scale research to industrial production.It is expected that the present piece of paper can contribute valuable guidance for further exploration and practical implementation in this emerging field of cosmetics.展开更多
It’s possible for malicious operators to seize hold of electrical control systems, for instance, the engine control unit of driverless vehicles, from various vectors, e.g. autonomic control system, remote vehicle acc...It’s possible for malicious operators to seize hold of electrical control systems, for instance, the engine control unit of driverless vehicles, from various vectors, e.g. autonomic control system, remote vehicle access, or human drivers. To mitigate potential risks, this paper provides the inauguration study by proposing a theoretical framework in the physical, human and cyber triad. Its goal is to, at each time point, detect adversary control behaviors and protect control systems against malicious operations via integrating a variety of methods. This paper only proposes a theoretical framework which tries to indicate possible threats. With the support of the framework, the security system can lightly reduce the risk. The development and implementation of the system are out of scope.展开更多
This paper presents and describes an approach to generate innovative labeled datasets that enable automated text classifiers to automatically detect online employee reviews referring to accounting control deficiencies...This paper presents and describes an approach to generate innovative labeled datasets that enable automated text classifiers to automatically detect online employee reviews referring to accounting control deficiencies,facili-tating supplementary monitoring for auditors and management.Employees,who are on the front lines executing policies and procedures,play a critical role in a firm's control environment.Their feedback provides insights into how controls are functioning.Textual data were collected and manually coded using a structured coding scheme mapped to COSO internal control framework(2013)principles.The dataset is unique in that it provides a new source of data that has not been previously used in internal control research,offering new opportunities for exploring the relationship between employee feedback and control weaknesses,and shedding light on potential improvements in internal control practices.Downstream stakeholders(such as researchers,management,in-vestors,and auditors)can benefit by having rapid,automated means for filtering and prioritizing employee reviews for further investigation,with respect to accounting control issue mentions.展开更多
We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of ...We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and,unlike the state of the art,requires neither weakcoupling Lamb-Dicke approximation nor perturbation treatment.With the application of gradient-based optimal control,it enables finding amplitude-and phase-modulated laser control protocols that work without the Lamb-Dicke approximation,promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies.Also,robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections.Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation,and thus can find applications in near-future experiments.展开更多
基金supported in part by the National Natural Science Foundation of China(62522313,62473207,U25A20301)the Fundamental Research Funds for the Central Universities(2024SMECP03)。
文摘Dear Editor,This letter addresses the challenge of achieving robust global coordination in multi-agent systems(MASs)subject to heterogeneous actuator saturation and additive input disturbances.We develop a novel distributed control framework that strategically integrates a redesigned saturation function to handle the nonlinear actuator constraint and a high-gain feedback mechanism for effective disturbance rejection.
基金sponsored by National Natural Science Foundation of China (Nos. 61673327, 51606161, 11602209, 91441128)Natural Science Foundation of Fujian Province of China (No. 2016J06011)China Scholarship Council (No. 201606310153)
文摘This paper addresses a target-enclosing problem for multiple spacecraft systems by proposing a two-layer affine formation control strategy. Compared with the existing methods,the adopted two-layer network structure in this paper is generally directed, which is suitable for practical space missions. Firstly, distributed finite-time sliding-mode estimators and formation controllers in both layers are designed separately to improve the flexibility of the formation control system. By introducing the properties of affine transformation into formation control protocol design,the controllers can be used to track different time-varying target formation patterns. Besides, multilayer time-varying encirclements can be achieved with particular shapes to surround the moving target. In the sequel, by integrating adaptive neural networks and specialized artificial potential functions into backstepping controllers, the problems of uncertain Euler-Lagrange models, collision avoidance as well as formation reconfiguration are solved simultaneously. The stability of the proposed controllers is verified by the Lyapunov direct method. Finally, two simulation examples of triangle formation and more complex hexagon formation are presented to illustrate the feasibility of the theoretical results.
基金the National Natural Science Foundation of China(61933010)the Natural Science Basic Research Plan in Shaanxi Province of China(2023-JC-QN-0733).
文摘This paper tackles the formation-containment control problem of fixed-wing unmanned aerial vehicle(UAV)swarm with model uncertainties for dynamic target tracking in three-dimensional space in the faulty case of UAVs’actuator and sensor.The fixed-wing UAV swarm under consideration is organized as a“multi-leader-multi-follower”structure,in which only several leaders can obtain the dynamic target information while others only receive the neighbors’information through the communication network.To simultaneously realize the formation,containment,and dynamic target tracking,a two-layer control framework is adopted to decouple the problem into two subproblems:reference trajectory generation and trajectory tracking.In the upper layer,a distributed finite-time estimator(DFTE)is proposed to generate each UAV’s reference trajectory in accordance with the control objective.Subsequently,a distributed composite robust fault-tolerant trajectory tracking controller is developed in the lower layer,where a novel adaptive extended super-twisting(AESTW)algorithm with a finite-time extended state observer(FTESO)is involved in solving the robust trajectory tracking control problem under model uncertainties,actuator,and sensor faults.The proposed controller simultaneously guarantees rapidness and enhances the system’s robustness with fewer chattering effects.Finally,corresponding simulations are carried out to demonstrate the effectiveness and competitiveness of the proposed two-layer fault-tolerant cooperative control scheme.
基金the National Key R&D Program of China(No.2017YFC0504903)the Project of Education Department of Sichuan Province(No.18ZA0408)the Opening Laboratory Project of Sichuan Normal University(No.KFSY2018022)。
文摘A series of Tb-based metal-organic frameworks(Tb-MOFs)were successfully synthesized by a solvothermal method.The size and morphology of the as-obtained Tb-MOFs can be effectively controlled via regulating the experimental conditions such as the volume fraction of DMF and the molar ratio of Tb^(3+)to NaOH.It is found that all the samples exhibit strong green emissions under ultraviolet excitation,corresponding to^(5)D_(4)→^(7)F_(J)transitions of Tb^(3+).Interestingly,Tb-MOFs displayed an efficient and distinct luminescence quenching by Cu^(2+)in aqueous solutions.The competitive fluorescence detection experiments indicate that these Tb-MOFs sensors can be used as a high selective and sensitive sensor of Cu^(2+)detection with the detection limit of 10μmol·L^(-1),which can be used as a promising fluorescence sensor for Cu^(2+)detection in daily life.
基金supported by Doctoral Foundation of Ministry of Education of China (Grant No.20070006011)
文摘For the constant distance spacing policy,the existing researches of the string stability focus on the single-predecessor information framework（SPIF） and predecessor-successor information framework（PSIF）.The research results demonstrated that the string stability could not be guaranteed with the SPIF,and then the PSIF was proposed to resolve this string instability.But the issue,whether the string stability can be guaranteed when applying the PSIF,is still controversial.Meanwhile,most of the previous researches on the string stability were conducted without consideration of the parasitic time delays and lags.In this paper,the practical longitudinal vehicle dynamics model is built with consideration of the parasitic time delays and lags existing in the actuators,sensors or the communication systems.Secondly,the detailed theoretical analysis of string stability in frequency domain is conducted to demonstrate that the classical linear control laws can not ensure the string stability when applying both the symmetrical PSIF（SPSIF） and asymmetrical PSIF（APSIF）.Thirdly,a control law,which adds the position and velocity information of the leading vehicle,is proposed to guarantee string stability for small/medium platoon,and the other control law,which adds the acceleration information of the controlled vehicle,is proposed to guarantee string stability for large platoon as well as small/medium platoon.Finally,the comparative simulation is conducted to confirm the conducted analysis and the proposed control laws.The conducted research completes the means to analyze the string stability in frequency domain,provides the parameters＇ reference for the design and implementation of the practical automatic following controllers,and improves the reliability and stability of the platoon of automatic vehicles.
文摘Weighted factor is given to access eontrol policies to express the importanceof policy and its effect on access control decision. According to this weighted access controlframework, a trustworthiness model for aceess request is also given. In this model, we give themeasure of trustworthiness factor to access request- by using some idea of uncertainty reasoning ofexpert system, present and prove the parallel propagation formula of request trustworthiness factoramong multiple policies, and get thefinal trustworthiness factor to decide whether authorizing. Inthis model, authorization decision is given according to the calculation of request trustworthinessfactor, which is more understandable, more suitable for real requirement and more powerfulforsecurity enhancement than traditional methods. Meanwhile the finer access control granularity isanother advantage.
基金the National Natural Science Foundation of China(Nos.21432004,21529201,and 91527301)the Ministry of Science and Technology of China(No.2013CB834501)+1 种基金the Ministry of Education of China Research Fund for the Doctoral Program and of China for financial supportsupport from the Molecular Foundry,Lawrence Berkeley National Laboratory,supported by the Office of Science,Office of Basic Energy Sciences,Scientific User Facilities Division,of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231
文摘Water-soluble three-dimensional porous supramolecular organic frameworks（SOFs） have been demonstrated as a new generation of homogeneous polycationic platforms for anti-cancer drug delivery.The new SOF drug delivery systems（sof-DDSs） can adsorb dianionic pemetrexed（PMX）,a clinically used chemotherapeutic agent instantaneously upon dissolving in water,which is driven by both electrostatic attraction and hydrophobicity.The in situ-prepared PMX@SOFs are highly stable and can avoid important release of the drug during plasm circulation and overcome the multidrug resistance of human breast MCF-7/Adr cancer cells to enter the cancer cells.Acidic microenvironment of cancer cells promotes the release of the drug in cancer cells.Both in vitro and in vivo studies have revealed that sofDDSs considerably improve the treatment efficacy of PMX,leading to 6-12-fold reduction of the IC50 values,as compared with that of PMX alone.The new drug delivery strategy omits the loading process required by most of reported nanoparticle-based delivery systems and thus holds promise for future development of low-cost drug delivery systems
文摘Cloud computing is touted as the next big thing in the Information Technology (IT) industry, which is going to impact the businesses of any size and yet the security issue continues to pose a big threat on it. The security and privacy issues persisting in cloud computing have proved to be an obstacle for its widespread adoption. In this paper, we look at these issues from a business perspective and how they are damaging the reputation of big companies. There is a literature review on the existing issues in cloud computing and how they are being tackled by the Cloud Service Providers (CSP). We propose a governing body framework which aims at solving these issues by establishing relationship amongst the CSPs in which the data about possible threats can be generated based on the previous attacks on other CSPs. The Governing Body will be responsible for Data Center control, Policy control, legal control, user awareness, performance evaluation, solution architecture and providing motivation for the entities involved.
基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB20000000)the National Nature Science Foundation of China(No.51603206)the Nature Science Foundation of Fujian Province(No.2016J05056)。
文摘The controlled self-assembly of discrete metal-organic nanocapsules(MONCs),and metal-organic frameworks(MOFs)based on the MONCs are achieved.Specifically,the solvothermal reaction of nickel nitrate hexahydrate and C-methylpyrogallol[4]arene in mixed DMF/MeOH solution leads to the unexpected form of discrete nickel-seamed hexameric pyrogallol[4]arene MONCs,and MONC-based three-dimensional(3D)MOF.Notably,the latter MOF is constructed from the aforementioned nickelseamed MONC building blocks and formate linkers in-situ generated from the hydrolysis of DMF solve nt.Interestingly,introducing pyridine and formic acid in the reaction conditions leads to the controlled assemblies of the discrete MONC and MONC-based 3D MOF structures.Moreover,the variabletemperature magnetic susceptibilities of both the abovementioned compounds have been investigated,indicating typical antiferromagnetic interactions between the metal centers.
基金Project supported by the National Natural Science Foundation of China(Grant No.60504033)
文摘In the paper, an iterative method is presented to the optimal control of batch processes. Generally it is very difficult to acquire an accurate mechanistic model for a batch process. Because support vector machine is powerful for the problems characterized by small samples, nonlinearity, high dimension and local minima, support vector regression models are developed for the optimal control of batch processes where end-point properties are required. The model parameters are selected within the Bayesian evidence framework. Based on the model, an iterative method is used to exploit the repetitive nature of batch processes to determine the optimal operating policy. Numerical simulation shows that the iterative optimal control can improve the process performance through iterations.
基金This work was supported by the National Natural Science Foundation of China(62020106003,62073029)the Beijing Natural Science Foundation(4202045)the Fundamental Research Funds for the Central Universities(FRF-TP-20-012A3).
文摘Initiated three decades ago,integrated design of controllers and fault detectors has continuously attracted research attention.The recent development of the unified control and detection framework with an observer-based residual generator in its core gives a more general form of the previous works.Its applications to residual centred modelling of uncertain control systems,fault detection in feedback control systems with uncertainties,fault-tolerant control(FTC)as well as control performance degradation monitoring,detection and recovery are introduced.In conclusion,some future perspectives are proposed.
基金funded by the Gansu Provincial Science and Technology Information Disclosure System Project(21ZD8JA001)Tianyou Innovation Team of Lanzhou Jiaotong University(TY202009).
文摘To address the frequency fluctuation problem caused by the power dynamic imbalance between the power system and the loadwhen a large number of newenergy sources are connected to the grid,a two-layer fuzzy control strategy is proposed for the participation of the energy storage battery system in FM.Firstly,considering the coordination of FM units responding to automatic power generation control commands,a comprehensive allocation strategy of two signals under automatic power generation control commands is proposed to give full play to the advantages of two FM signals while enabling better coordination of two FM units responding to FM commands;secondly,based on the grid FM demand and battery FM capability,a double-layer fuzzy control strategy is proposed for FM units responding to automatic power generation control commands in a coordinated manner under dual-signal allocation mode to precisely allocate the power output depth of FM units,which can control the fluctuation of frequency deviation within a smaller range at a faster speed while maintaining the battery charge state;finally,the proposed Finally,the proposed control strategy is simulated and verified inMatlab/Simulink.The results show that the proposed control strategy can control the frequency deviation within a smaller range in a shorter time,better stabilize the fluctuation of the battery charge level,and improve the utilization of the FM unit.
基金supported by the Science and Technology Development Plan Issue of Jinlin Province(20060217)
文摘In view of the currant status of the quality risk control of livestock products, the differences between the quality, safety and risk of the livestock products were pointed clearly; the derivative mechanism model of the quality risk was studied; the risk system of livestock products was established; and the types of controllable risk were identified. On this basis, the design principles of risk control framework were established. Then the modular system of risk control was constructed and the attributes of production system were detailed into the describable indicators of risk control based on the thrae-dimensional risks.
基金Sponsored by the National Natural Science Foundation of China (Grant No. 60776816)Scientific Research Foundation of Education Department of Yunnan Province (Grant No.08Y10326)
文摘Aiming at the tele-operation instability caused by time delay of interuet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-roboties, which can guarantee the non-distortion-transfer of control information and reduce the difference of action time between the local simulated virtual robot and the remote real robot. This framework is insensitive to the inherent interact time delay, and differs from other tele-robotics systems that try to use some mathematic models to describe the internet delay or take some assumptions. In order to verify the framework, a 4-DOF fischertechnik industry robot tele-operation system has been developed using the new proposed framework. Experimental results demonstrate the applicable performance of the new framework. The framework is open structured and can be applied to other general purposed tele-operation systems.
基金This work was supported in part by National NSF of China(Nos.61872095,61872128,61571139 and 61201393)New Star of Pearl River on Science and Technology of Guangzhou(No.2014J2200085)+2 种基金the Open Project Program of Shenzhen Key Laboratory of Media Security(Grant No.ML-2018-03)the Opening Project of Guang Dong Province Key Laboratory of Information Security Technology(Grant No.2017B030314131-15)Natural Science Foundation of Xizang(No.2016ZR-MZ-01).
文摘This paper proposes a two-step general framework for reversible data hiding(RDH)schemes with controllable contrast enhancement.The first step aims at preserving visual perception as much as possible on the basis of achieving high embedding capacity(EC),while the second step is used for increasing image contrast.In the second step,some peak-pairs are utilized so that the histogram of pixel values is modified to perform histogram equalization(HE),which would lead to the image contrast enhancement.However,for HE,the utilization of some peak-pairs easily leads to over-enhanced image contrast when a large number of bits are embedded.Therefore,in our proposed framework,contrast over-enhancement is avoided by controlling the degree of contrast enhancement.Since the second step can only provide a small amount of data due to controlled contrast enhancement,the first one helps to achieve a large amount of data without degrading visual quality.Any RDH method which can achieve high EC while preserve good visual quality,can be selected for the first step.In fact,Gao et al.’s method is a special case of our proposed framework.In addition,two simple and commonly-used RDH methods are also introduced to further demonstrate the generalization of our framework.
基金funded by the Chongqing Water Resources Bureau,China(Project No.CQS24C00836).
文摘We proposes an AI-assisted framework for integrated natural disaster prevention and emergency response,leveraging the DeepSeek large language model(LLM)to advance intelligent decision-making in geohazard management.We systematically analyze the technical pathways for deploying LLMs in disaster scenarios,emphasizing three breakthrough directions:(1)knowledge graph-driven dynamic risk modeling,(2)reinforcement learning-optimized emergency decision systems,and(3)secure local deployment architectures.The DeepSeek model demonstrates unique advantages through its hybrid reasoning mechanism combining semantic analysis with geospatial pattern recognition,enabling cost-effective processing of multi-source data spanning historical disaster records,real-time IoT sensor feeds,and socio-environmental parameters.A modular system architecture is designed to achieve three critical objectives:(a)automated construction of domain-specific knowledge graphs through unsupervised learning of disaster physics relationships,(b)scenario-adaptive resource allocation using risk simulations,and(c)preserving emergency coordination via federated learning across distributed response nodes.The proposed local deployment paradigm addresses critical data security concerns in cross-border disaster management while complying with the FAIR principles(Findable,Accessible,Interoperable,Reusable)for geoscientific data governance.This work establishes a methodological foundation for next-generation AI-earth science convergence in disaster mitigation.
文摘Metal-organic frameworks(MOFs)represent a class of multifunctional hybrid materials distinguished by their tunable structural architectures,adjustable pore dimensions,and tailorable surface chemical functionalities,which underpin their broad applicability across diverse domains.Within the cosmetics industry,MOFs exhibit significant application potential owing to their high thermal and chemical stability,substantial loading capacity,low biological toxicity,favorable luminescent characteristics,and robust catalytic activity,leading to their increasing deployment in various cosmetic-related applications.This article systematically outlines the structural features and functional properties of MOFs,emphasizing their suitability for integration into cosmetic systems.Furthermore,it provides a comprehensive review of recent advances in the utilization of MOFs in cosmetics,encompassing the detection of organic contaminants and metal ions,ultraviolet protection,encapsulation,and controlled release of volatile active ingredients,as well as targeted delivery of dermatological therapeutic agents.The structure-property-application relationships of MOFs are critically examined.Building upon the foundation of existing research,this study offers a comprehensive outlook on the future development of MOFs in the field of cosmetics.It presents several strategic perspectives,including an in-depth analysis of current application studies,the expansion of MOFs applications into additional cosmetic domains,the integration of multifunctional MOFs systems,the development of MOFs-based composite materials,and the scale-up of synthesis processes from laboratory-scale research to industrial production.It is expected that the present piece of paper can contribute valuable guidance for further exploration and practical implementation in this emerging field of cosmetics.
文摘It’s possible for malicious operators to seize hold of electrical control systems, for instance, the engine control unit of driverless vehicles, from various vectors, e.g. autonomic control system, remote vehicle access, or human drivers. To mitigate potential risks, this paper provides the inauguration study by proposing a theoretical framework in the physical, human and cyber triad. Its goal is to, at each time point, detect adversary control behaviors and protect control systems against malicious operations via integrating a variety of methods. This paper only proposes a theoretical framework which tries to indicate possible threats. With the support of the framework, the security system can lightly reduce the risk. The development and implementation of the system are out of scope.
文摘This paper presents and describes an approach to generate innovative labeled datasets that enable automated text classifiers to automatically detect online employee reviews referring to accounting control deficiencies,facili-tating supplementary monitoring for auditors and management.Employees,who are on the front lines executing policies and procedures,play a critical role in a firm's control environment.Their feedback provides insights into how controls are functioning.Textual data were collected and manually coded using a structured coding scheme mapped to COSO internal control framework(2013)principles.The dataset is unique in that it provides a new source of data that has not been previously used in internal control research,offering new opportunities for exploring the relationship between employee feedback and control weaknesses,and shedding light on potential improvements in internal control practices.Downstream stakeholders(such as researchers,management,in-vestors,and auditors)can benefit by having rapid,automated means for filtering and prioritizing employee reviews for further investigation,with respect to accounting control issue mentions.
基金supported by the National Natural Science Foundation of China(Grant Nos.12441502,12122506,12204230,and 12404554)the National Science and Technology Major Project of the Ministry of Science and Technology of China(2024ZD0300404)+6 种基金Guangdong Basic and Applied Basic Research Foundation(Grant No.2021B1515020070)Shenzhen Science and Technology Program(Grant No.RCYX20200714114522109)China Postdoctoral Science Foundation(CPSF)(2024M762114)Postdoctoral Fellowship Program of CPSF(GZC20231727)supported by the National Natural Science Foundation of China(Grant Nos.92165206 and 11974330)Innovation Program for Quantum Science and Technology(Grant No.2021ZD0301603)the Fundamental Research Funds for the Central Universities。
文摘We present a robust quantum optimal control framework for implementing fast entangling gates on ion-trap quantum processors.The framework leverages tailored laser pulses to drive the multiple vibrational sidebands of the ions to create phonon-mediated entangling gates and,unlike the state of the art,requires neither weakcoupling Lamb-Dicke approximation nor perturbation treatment.With the application of gradient-based optimal control,it enables finding amplitude-and phase-modulated laser control protocols that work without the Lamb-Dicke approximation,promising gate speeds on the order of microseconds comparable to the characteristic trap frequencies.Also,robustness requirements on the temperature of the ions and initial optical phase can be conveniently included to pursue high-quality fast gates against experimental imperfections.Our approach represents a step in speeding up quantum gates to achieve larger quantum circuits for quantum computation and simulation,and thus can find applications in near-future experiments.
