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
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
Aiming at the tele-operation instability caused by time delay of internet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-robotics, which ca...Aiming at the tele-operation instability caused by time delay of internet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-robotics, 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 internet 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
Due to the current global oil price,the sand production is considered undesirable product and the control of sand production is considered as one of the main concerns of production engineers.It can damage downhole,sub...Due to the current global oil price,the sand production is considered undesirable product and the control of sand production is considered as one of the main concerns of production engineers.It can damage downhole,subsea equipments and surface production facilities,also increasing the risk of catastrophic failure.As a result of that it costs the producers multiple millions of dollars each year.Therefore,there are many different approaches of sand control designed for different reservoir conditions.Selecting an appropriate technique for preventing formation sand production depends on different reservoir parameters.Therefore,choosing the best sand control method is the result of systematic study.In this paper the sand production factors and their effects are presented where the emphasis is given towards the sand prediction to determine the probability of producing sand from the reservoir,followed by the correct prevention implementation of sand control method.The combination of these two is presented as a smart control framework that can be applied for sand production management.展开更多
The coordinate landing control of the unmanned aerial vehicles(UAVs)is a key technology to expand the cooperation between the UAVs and the unmanned surface vehicle(USV).This paper provides an eagle vision-based coordi...The coordinate landing control of the unmanned aerial vehicles(UAVs)is a key technology to expand the cooperation between the UAVs and the unmanned surface vehicle(USV).This paper provides an eagle vision-based coordinate landing control framework for the UAV swarm landing on a USV.Back-stepping controller is designed to guarantee that the tracking errors in both of the approaching stage and the landing stage converge to zero.Eagle vision is applied in the visual navigation to improve the landing accuracy.The experiment verified the feasibility of the proposed method.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
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
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
The research on legged robots attracted much attention both from the academia and industry. Legged robots are multi-input multi-output with multiple end-e ector systems. Therefore,the mechanical design and control fra...The research on legged robots attracted much attention both from the academia and industry. Legged robots are multi-input multi-output with multiple end-e ector systems. Therefore,the mechanical design and control framework are challenging issues. This paper reviews the development of type synthesis and behavior control on legged robots; introduces the hexapod robots developed in our research group based on the proposed type synthesis method. The control framework for legged robots includes data driven layer,robot behavior layer and robot execution layer. Each layer consists several components which are explained in details. Finally,various experiments were conducted on several hexapod robots. The summarization of the type synthesis and behavior control design constructed in this paper would provide a unified platform for communications and references for future advancement for legged robots.展开更多
为识别中国生态环境治理研究的薄弱环节,提出对策建议以期推动中国生态环境治理的高效提升,基于中国知网(CNKI)与Web of Science核心数据库,采用知识图谱可视化方法,系统梳理1998-2023年中国生态环境治理的发展动态和知识架构,并与国外...为识别中国生态环境治理研究的薄弱环节,提出对策建议以期推动中国生态环境治理的高效提升,基于中国知网(CNKI)与Web of Science核心数据库,采用知识图谱可视化方法,系统梳理1998-2023年中国生态环境治理的发展动态和知识架构,并与国外知识体系进行比较分析,识别出中国研究的薄弱环节,并提出针对性的完善建议。结果表明:①中国生态环境治理研究经历了环境问题控制与治理策略探索、环境问题防控与治理策略优化、战略目标引领治理策略深化和生态环境保护与修复四个阶段,并呈现出以国家战略为引领,由分散向系统治理、单一主体向多元主体协同共治、传统治理向信息化治理转变的中国特质。②中国生态环境治理研究知识体系涵盖治理模式与政策、污染治理、环境治理与社会经济关联关系、绿色发展与全球治理、生态文明引领下环境治理、信息化治理六方面。③中国生态环境治理研究薄弱环节包括实践层面上的监督政策机制尚待完善、环保与经济发展协调有待加强、公众环保意识尚待提升、生态保护与修复失调以及理论层面上的简单套用国外经验、缺乏具有中国特色的综合治理体系和实践案例研究等。对比国外治理知识体系,建议未来中国生态环境治理研究从环境法律法规制度、环境治理体制机制创新和生态环境智慧治理等方面完善。展开更多
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.
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 internet information transfer for internet based tele-robotics, this paper proposes a novel control framework for internet based tele-robotics, 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 internet 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.
文摘Due to the current global oil price,the sand production is considered undesirable product and the control of sand production is considered as one of the main concerns of production engineers.It can damage downhole,subsea equipments and surface production facilities,also increasing the risk of catastrophic failure.As a result of that it costs the producers multiple millions of dollars each year.Therefore,there are many different approaches of sand control designed for different reservoir conditions.Selecting an appropriate technique for preventing formation sand production depends on different reservoir parameters.Therefore,choosing the best sand control method is the result of systematic study.In this paper the sand production factors and their effects are presented where the emphasis is given towards the sand prediction to determine the probability of producing sand from the reservoir,followed by the correct prevention implementation of sand control method.The combination of these two is presented as a smart control framework that can be applied for sand production management.
基金partially supported by National Natural Science Foundation of China under Grants #U1913602,#U20B2071,#91948204 and #T2121003.
文摘The coordinate landing control of the unmanned aerial vehicles(UAVs)is a key technology to expand the cooperation between the UAVs and the unmanned surface vehicle(USV).This paper provides an eagle vision-based coordinate landing control framework for the UAV swarm landing on a USV.Back-stepping controller is designed to guarantee that the tracking errors in both of the approaching stage and the landing stage converge to zero.Eagle vision is applied in the visual navigation to improve the landing accuracy.The experiment verified the feasibility of the proposed method.
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.
基金Supported by National Natural Science Foundation of China(Grant No.U1613208)
文摘The research on legged robots attracted much attention both from the academia and industry. Legged robots are multi-input multi-output with multiple end-e ector systems. Therefore,the mechanical design and control framework are challenging issues. This paper reviews the development of type synthesis and behavior control on legged robots; introduces the hexapod robots developed in our research group based on the proposed type synthesis method. The control framework for legged robots includes data driven layer,robot behavior layer and robot execution layer. Each layer consists several components which are explained in details. Finally,various experiments were conducted on several hexapod robots. The summarization of the type synthesis and behavior control design constructed in this paper would provide a unified platform for communications and references for future advancement for legged robots.
文摘为识别中国生态环境治理研究的薄弱环节,提出对策建议以期推动中国生态环境治理的高效提升,基于中国知网(CNKI)与Web of Science核心数据库,采用知识图谱可视化方法,系统梳理1998-2023年中国生态环境治理的发展动态和知识架构,并与国外知识体系进行比较分析,识别出中国研究的薄弱环节,并提出针对性的完善建议。结果表明:①中国生态环境治理研究经历了环境问题控制与治理策略探索、环境问题防控与治理策略优化、战略目标引领治理策略深化和生态环境保护与修复四个阶段,并呈现出以国家战略为引领,由分散向系统治理、单一主体向多元主体协同共治、传统治理向信息化治理转变的中国特质。②中国生态环境治理研究知识体系涵盖治理模式与政策、污染治理、环境治理与社会经济关联关系、绿色发展与全球治理、生态文明引领下环境治理、信息化治理六方面。③中国生态环境治理研究薄弱环节包括实践层面上的监督政策机制尚待完善、环保与经济发展协调有待加强、公众环保意识尚待提升、生态保护与修复失调以及理论层面上的简单套用国外经验、缺乏具有中国特色的综合治理体系和实践案例研究等。对比国外治理知识体系,建议未来中国生态环境治理研究从环境法律法规制度、环境治理体制机制创新和生态环境智慧治理等方面完善。
