The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption th...The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.展开更多
Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper p...Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ reactor.The passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety systems.When the SBLOCA occurred,the RMTs were initiated.The water in the RMTs was then injected into the pressure vessel.The RMTs' low water level triggered the PDS,which depressurized the coolant system drastically.As the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the core.The results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant.展开更多
Recent advancements in passive wireless sensor technology have significantly extended the application scope of sensing,particularly in challenging environments for monitoring industry and healthcare applications.These...Recent advancements in passive wireless sensor technology have significantly extended the application scope of sensing,particularly in challenging environments for monitoring industry and healthcare applications.These systems are equipped with battery-free operation,wireless connectivity,and are designed to be both miniaturized and lightweight.Such features enable the safe,real-time monitoring of industrial environments and support high-precision physiological measurements in confined internal body spaces and on wearable epidermal devices.Despite the exploration into diverse application environments,the development of a systematic and comprehensive research framework for system architecture remains elusive,which hampers further optimization of these systems.This review,therefore,begins with an examination of application scenarios,progresses to evaluate current system architectures,and discusses the function of each component—specifically,the passive sensor module,the wireless communication model,and the readout module—within the context of key implementations in target sensing systems.Furthermore,we present case studies that demonstrate the feasibility of proposed classified components for sensing scenarios,derived from this systematic approach.By outlining a research trajectory for the application of passive wireless systems in sensing technologies,this paper aims to establish a foundation for more advanced,user-friendly applications.展开更多
The passive containment heat removal system(PCS)is one of the key passive safety systems of China’s third-generation advanced pressurized water reactor-Hua-long Pressurized Reactor(HPR1000),used to prevent overpressu...The passive containment heat removal system(PCS)is one of the key passive safety systems of China’s third-generation advanced pressurized water reactor-Hua-long Pressurized Reactor(HPR1000),used to prevent overpressure of large concrete containment under severe accident scenarios.This paper provides an overview of the development of the HPR1000 passive containment heat removal system,including its operating principles and configuration,internal heat exchanger design,feasibility tests,engineering-scale PCS verification tests,comprehensive tests on PCS-containment coupling characteristics,among other key supporting studies.These extensive studies demonstrated that the PCS of HPR1000,which is designed based on flashing-driven open natural circulation and efficient condensation heat transfer theory,can work effectively and ensure the integrity of the containment under various accident scenarios.The system has been applied to Fuqing No.5 and No.6 nuclear power units and Zhangzhou No.1 and No.2 units of China’s first million-kilowatt third-generation nuclear power HPR1000.It is also applied to K-2/K-3 units of Karachi Nuclear Power Plant in Pakistan.展开更多
With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by ad...With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision.展开更多
To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environme...To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.展开更多
According to the characteristics of gravity passive navigation, this paper presents a novel gravity passive navigation system （GPNS）, which consists of the rate azimuth platform （RAP）, gravity sensor, digitally st...According to the characteristics of gravity passive navigation, this paper presents a novel gravity passive navigation system （GPNS）, which consists of the rate azimuth platform （RAP）, gravity sensor, digitally stored gravity maps, depth sensor and relative log. The algorithm of rate azimuth platform inertial navigation system, error state-space equations, measurement equations and GPNS optimal filter are described. In view of the measurements made by an onboard gravity sensor the Eotvos effect is introduced in the gravity measurement equation of a GPNS optimal filter. A GPNS is studied with the Matlab/Simulink tools; simulation results demonstrate that a GPNS has small errors in platform attitude and position. Because the inertial navigation platform is the rate azimuth platform in the GPNS and gravity sensor is mounted on the rate azimuth platform, the cost of the GPNS is lower than existing GPNS＇s and according to the above results the GPNS meets the need to maintain accuracy navigation for underwater vehicles over long intervals.展开更多
In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and...In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.展开更多
Permanent Magnet Synchronous Motor model can exhibit a variety of chaotic phenomena under some choices of system parameters and external input. Based on the property of passive system, the essential conditions were st...Permanent Magnet Synchronous Motor model can exhibit a variety of chaotic phenomena under some choices of system parameters and external input. Based on the property of passive system, the essential conditions were studied, by which Permanent Magnet Synchronous Motor chaotic system could be equivalent to passive system. Using Lyapunov stability theory, the convergence condition deciding the system's characters was discussed. In the convergence condition area, the equivalent passive system could be globally asymptotically stabilized by smooth state feedback.展开更多
Passive system theory was applied to propose a new passive control method with nonlinear observer of the Permanent Magnet Synchronous Motor chaotic system. Through constructing a Lyapunov function, the subsystem of th...Passive system theory was applied to propose a new passive control method with nonlinear observer of the Permanent Magnet Synchronous Motor chaotic system. Through constructing a Lyapunov function, the subsystem of the Permanent Magnet Synchronous Motor chaotic system could be proved to be globally stable at the equilibrium point. Then a controller with smooth state feedback is designed so that the Permanent Magnet Synchronous Motor chaotic system can be equivalent to a passive system. To get the state variables of the controller, the nonlinear observer is also studied. It is found that the outputs of the nonlinear observer can approximate the state variables of the Permanent Magnet Synchronous Motor chaotic system if the system’s nonlinear function is a globally Lipschitz function. Simulation results showed that the equivalent passive system of Permanent Magnet Synchronous Motor chaotic system could be globally asymptotically stabilized by smooth state feedback in the observed parameter convergence condition area.展开更多
Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are w...Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new,dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall,and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).展开更多
Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for build...Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for buildings are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).展开更多
Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturban...Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturbance is called extra torque. The most important issue for PTSS controller design is how to eliminate the influence of extra torque. Using backstepping technique, adaptive fuzzy torque control (AFTC) algorithm is proposed for PTSS in this paper, which reflects the essential characteristics of PTSS and guarantees transient tracking performance as well as final tracking accuracy. Takagi-Sugeno (T-S) fuzzy logic system is utilized to compensate parametric uncertainties and unstructured uncertainties. The output velocity of actuator identified model is introduced into AFTC aiming to eliminate extra torque. The closed-loop stability is studied using small gain theorem and the control system is proved to be semiglobally uniformly ultimately bounded. The proposed AFTC algorithm is applied to an electric load simulator (ELS), and the comparative experimental results indicate that AFTC controller is effective for PTSS.展开更多
AIM To assess for passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts(TIPS) and compare outcomes with maximally dilated TIPS.METHODS Polytetrafluoroethylene covered TIPS(Viatorr) ...AIM To assess for passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts(TIPS) and compare outcomes with maximally dilated TIPS.METHODS Polytetrafluoroethylene covered TIPS(Viatorr) from July 2002 to December 2013 were retrospectively reviewed at two hospitals in a single institution. Two hundred and thirty patients had TIPS maximally dilated to 10 mm(m TIPS), while 43 patients who were at increased risk for hepatic encephalopathy(HE), based on clinical evaluation or low pre-TIPS portosystemic gradient(PSG), had 10 mm TIPS sub-maximally dilated to 8 mm(sm TIPS). Group characteristics(age, gender, Model for End-Stage Liver Disease score, post-TIPS PSG and clinical outcomes were compared between groups, including clinical success(ascites or varices), primary patency,primary assisted patency, and severe post-TIPS HE. A subset of fourteen patients with sm TIPS underwent follow-up computed tomography imaging after TIPS creation, and were grouped based on time of imaging(< 6 mo and > 6 mo). Change in diameter and crosssectional area were measured with 3D imaging software to evaluate for passive expansion.RESULTS Patient characteristics were similar between the sm TIPS and m TIPS groups, except for pre-TIPS portosystemic gradient, which was lower in the sm TIPS group(19.4 mm Hg ± 6.8 vs 22.4 mm Hg ± 7.1, P = 0.01). Primary patency and primary assisted patency between sm TIPS and m TIPS was not significantly different(P = 0.64 and 0.55, respectively). Four of the 55 patients(7%) with sm TIPS required TIPS reduction for severe refractory HE, while this occurred in 6 of the 218 patients(3%) with m TIPS(P = 0.12). For the 14 patients with follow-up computed tomography(CT) imaging, the median imaging follow-up was 373 d. There was an increase in median TIPS diameter, median percent diameter change, median area, and median percent area change in patients with CT follow-up greater than 6 mo after TIPS placement compared to follow-up within 6 mo(8.45 mm, 5.58%, 56.04 mm^2, and 11.48%, respectively, P = 0.01).CONCLUSION Passive expansion of sm TIPS does occur but clinical outcomes of sm TIPS and m TIPS were similar. Sub-maximal dilation can prevent complications related to overshunting in select patients.展开更多
The limited availability of studies on the natural convection heat transfer characteristics of fluoride salt has hindered progress in the design of passive residual heat removal systems(PRHRS)for molten salt reactors....The limited availability of studies on the natural convection heat transfer characteristics of fluoride salt has hindered progress in the design of passive residual heat removal systems(PRHRS)for molten salt reactors.This paper presents results from a numerical investigation of natural convection heat transfer characteristics of fluoride salt and heat pipes in the drain tank of a PRHRS.Simulation results are compared with experimental data,demonstrating the accuracy of the calculation methodology.Temperature distribution of fluoride salt and heat transfer characteristics are obtained and analyzed.The radial temperature of liquid fluoride salt in the drain tank shows a uniform distribution,while temperatures increase with increase in axial height from the bottom to the top of the drain tank.In addition,natural convection intensity increases with increase in height of the heat pipes in the tank.Spacing between heat pipes has no obvious effect on the natural convection heat transfer coefficient.This study will contribute to the design of passive heat removal systems for advanced nuclear reactors.展开更多
This paper investigates the synchronization of a fractional order hyperchaotic system using passive control. A passive controller is designed, based on the properties of a passive system. Then the synchronization betw...This paper investigates the synchronization of a fractional order hyperchaotic system using passive control. A passive controller is designed, based on the properties of a passive system. Then the synchronization between two fractional order hyperchaotic systems under different initial conditions is realized, on the basis of the stability theorem for fractional order systems. Numerical simulations and circuitry simulations are presented to verify the analytical results.展开更多
In this paper we present a new simple controller for a chaotic system, that is, the Newton-Leipnik equation with two strange attractors： the upper attractor （UA） and the lower attractor （LA）. The controller desig...In this paper we present a new simple controller for a chaotic system, that is, the Newton-Leipnik equation with two strange attractors： the upper attractor （UA） and the lower attractor （LA）. The controller design is based on the passive technique. The final structure of this controller for original stabilization has a simple nonlinear feedback form. Using a passive method, we prove the stability of a closed-loop system. Based on the controller derived from the passive principle, we investigate three different kinds of chaotic control of the system, separately： the original control forcing the chaotic motion to settle down to the origin from an arbitrary position of the phase space; the chaotic intra-attractor control for stabilizing the equilibrium points only belonging to the upper chaotic attractor or the lower chaotic one, and the inter-attractor control for compelling the chaotic oscillation from one basin to another one. Both theoretical analysis and simulation results verify the validity of the suggested method.展开更多
In spectrum sharing systems,locating mul-tiple radiation sources can efficiently find out the in-truders,which protects the shared spectrum from ma-licious jamming or other unauthorized usage.Com-pared to single-sourc...In spectrum sharing systems,locating mul-tiple radiation sources can efficiently find out the in-truders,which protects the shared spectrum from ma-licious jamming or other unauthorized usage.Com-pared to single-source localization,simultaneously lo-cating multiple sources is more challenging in prac-tice since the association between measurement pa-rameters and source nodes are not known.More-over,the number of possible measurements-source as-sociations increases exponentially with the number of sensor nodes.It is crucial to discriminate which measurements correspond to the same source before localization.In this work,we propose a central-ized localization scheme to estimate the positions of multiple sources.Firstly,we develop two computa-tionally light methods to handle the unknown RSS-AOA measurements-source association problem.One method utilizes linear coordinate conversion to com-pute the minimum spatial Euclidean distance sum-mation of measurements.Another method exploits the long-short-term memory(LSTM)network to clas-sify the measurement sequences.Then,we propose a weighted least squares(WLS)approach to obtain the closed-form estimation of the positions by linearizing the non-convex localization problem.Numerical re-sults demonstrate that the proposed scheme could gain sufficient localization accuracy under adversarial sce-narios where the sources are in close proximity and the measurement noise is strong.展开更多
The exponential passive filtering problem for a class of nonlinear Markov jump systems with uncertainties and time-delays is studied. The uncertain parameters are assumed unknown but norm bounded, and the nonlineariti...The exponential passive filtering problem for a class of nonlinear Markov jump systems with uncertainties and time-delays is studied. The uncertain parameters are assumed unknown but norm bounded, and the nonlinearities satisfy the quadratic condition. Based on the passive filtering theory, the sufficient condition for the existence of the mode-dependent passive filter is given by analyzing the reconstructed observer system. By using the appropriate Lyapnnov-Krasovskii function and applying linear matrix inequalities, the design scheme of the passive filter is derived and described as an optimization one. The presented exponential passive filter makes the error dynamic systems exponentially stochastically stable for all the admissible uncertainties, time-delays and nonlinearities, has the better abilities of state tracking and satisfies the given passive norm index. Simulation results demonstrate the validity of the proposed approach.展开更多
Synchronization of a hyperchaotic Lorenz system is discussed using passive control. Based on the properties of a passive system, a passive controller is designed and the synchronization between two hyperchaotic Lorenz...Synchronization of a hyperchaotic Lorenz system is discussed using passive control. Based on the properties of a passive system, a passive controller is designed and the synchronization between two hyperchaotic Lorenz systems under different initial conditions is realized. Simulation results show the proposed synchronization method to be effective.展开更多
文摘The energy consumption of buildings in urban areas is one of the greatest source of energy wasting and, consequently, ofincreasing of CO2 emission. Research is currently focused on the reduction of this consumption through the use of passive air-conditioning systems, that can be integrated with conventional systems and give rise to the so-called hybrid systems. Historically, these passive systems were developed in the Mediterranean and Middle East area. The research approach on this topic involves the application of design strategies and the development of computational tools and control systems. The development of the hybrid systems is the result of the synergy between current scientific knowledge, advanced manufacturing and information technology. In this study, a modular housing system has been investigated under different conditions. Simulations have been repeated, in order to identify the configuration that provides the highest indoor comfort. The analysis of the different conditions has been carried out using a CFD （computational fluid dynamic） software. The paper shows the results developed by the Dipartimento di Architettura of the Universit^t di Palermo in the analysis of the natural ventilation effect on the indoor comfort.
基金supported by the National High-tech R&D Program of China(No.2012AA050905)
文摘Since the Fukushima accident in 2011,more and more attention has been paid to nuclear reactor safety.A number of evolutionary passive systems have been developed to enhance the inherent safety of reactors.This paper presents a passive safety system applied on CPR1000,which is a traditional generation II+ reactor.The passive components selected are as follows:(1) the reactor makeup tanks(RMTs);(2) the advanced accumulators(A-ACCs);(3) the passive emergency feedwater system(PEFS);(4)the passive depressurization system(PDS);(5) the incontainment refueling water storage tank(IRWST).The model of the coolant system and the passive systems was established by utilizing a system code(RELAP5/MOD3.3).The SBLOCA(small-break loss of coolant) was analyzed to test the passive safety systems.When the SBLOCA occurred,the RMTs were initiated.The water in the RMTs was then injected into the pressure vessel.The RMTs' low water level triggered the PDS,which depressurized the coolant system drastically.As the pressure of the coolant system decreased,the A-ACCs and the IRWST were put to work to prevent the uncovering of the core.The results show that,after the small-break loss-of-coolant accident,the passive systems can prevent uncovering of the core and guarantee the safety of the plant.
基金partially supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2018R1A6A1A03025242)by the Korea government(MIST)(RS-2023-00302751,RS-2024-00343686)the Research Grant of Kwangwoon University in 2024。
文摘Recent advancements in passive wireless sensor technology have significantly extended the application scope of sensing,particularly in challenging environments for monitoring industry and healthcare applications.These systems are equipped with battery-free operation,wireless connectivity,and are designed to be both miniaturized and lightweight.Such features enable the safe,real-time monitoring of industrial environments and support high-precision physiological measurements in confined internal body spaces and on wearable epidermal devices.Despite the exploration into diverse application environments,the development of a systematic and comprehensive research framework for system architecture remains elusive,which hampers further optimization of these systems.This review,therefore,begins with an examination of application scenarios,progresses to evaluate current system architectures,and discusses the function of each component—specifically,the passive sensor module,the wireless communication model,and the readout module—within the context of key implementations in target sensing systems.Furthermore,we present case studies that demonstrate the feasibility of proposed classified components for sensing scenarios,derived from this systematic approach.By outlining a research trajectory for the application of passive wireless systems in sensing technologies,this paper aims to establish a foundation for more advanced,user-friendly applications.
基金supported by China Nuclear Power Engineering Co.,Ltd.and Harbin Engineering University,and granted financial resources by China’s National Energy Administration and China National Nuclear Corporation.
文摘The passive containment heat removal system(PCS)is one of the key passive safety systems of China’s third-generation advanced pressurized water reactor-Hua-long Pressurized Reactor(HPR1000),used to prevent overpressure of large concrete containment under severe accident scenarios.This paper provides an overview of the development of the HPR1000 passive containment heat removal system,including its operating principles and configuration,internal heat exchanger design,feasibility tests,engineering-scale PCS verification tests,comprehensive tests on PCS-containment coupling characteristics,among other key supporting studies.These extensive studies demonstrated that the PCS of HPR1000,which is designed based on flashing-driven open natural circulation and efficient condensation heat transfer theory,can work effectively and ensure the integrity of the containment under various accident scenarios.The system has been applied to Fuqing No.5 and No.6 nuclear power units and Zhangzhou No.1 and No.2 units of China’s first million-kilowatt third-generation nuclear power HPR1000.It is also applied to K-2/K-3 units of Karachi Nuclear Power Plant in Pakistan.
文摘With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision.
基金Pre-Research Program of General Armament Department during the11th Five-Year Plan Period (No51309020503)the National Defense Basic Research Program of China (973Program)(No973-61334)+1 种基金the National Natural Science Foundation of China(No50575042)Specialized Research Fund for the Doctoral Program of Higher Education (No20050286026)
文摘To improve the navigation accuracy of an autonomous underwater vehicle （AUV）, a novel terrain passive integrated navigation system （TPINS） is presented. According to the characteristics of the underwater environment and AUV navigation requirements of low cost and high accuracy, a novel TPINS is designed with a configuration of the strapdown inertial navigation system （SINS）, the terrain reference navigation system （TRNS）, the Doppler velocity sonar （DVS）, the magnetic compass and the navigation computer utilizing the unscented Kalman filter （UKF） to fuse the navigation information from various navigation sensors. Linear filter equations for the extended Kalman filter （EKF）, nonlinear filter equations for the UKF and measurement equations of navigation sensors are addressed. It is indicated from the comparable simulation experiments of the EKF and the UKF that AUV navigation precision is improved substantially with the proposed sensors and the UKF when compared to the EKF. The TPINS designed with the proposed sensors and the UKF is effective in reducing AUV navigation position errors and improving the stability and precision of the AUV underwater integrated navigation.
文摘According to the characteristics of gravity passive navigation, this paper presents a novel gravity passive navigation system （GPNS）, which consists of the rate azimuth platform （RAP）, gravity sensor, digitally stored gravity maps, depth sensor and relative log. The algorithm of rate azimuth platform inertial navigation system, error state-space equations, measurement equations and GPNS optimal filter are described. In view of the measurements made by an onboard gravity sensor the Eotvos effect is introduced in the gravity measurement equation of a GPNS optimal filter. A GPNS is studied with the Matlab/Simulink tools; simulation results demonstrate that a GPNS has small errors in platform attitude and position. Because the inertial navigation platform is the rate azimuth platform in the GPNS and gravity sensor is mounted on the rate azimuth platform, the cost of the GPNS is lower than existing GPNS＇s and according to the above results the GPNS meets the need to maintain accuracy navigation for underwater vehicles over long intervals.
基金supported by Natural Sciences and Engineering Research Council of Canada (NSERC) Research Fellowship,Canada Research Chairs Program and University of Ottawa Research Chair Program
文摘In this paper,the problem of time varying telecommunication delays in passive teleoperation systems is addressed.The design comprises delayed position,velocity and position-velocity signals with the local position and velocity signals of the master and slave manipulators.Nonlinear adaptive control terms are employed locally to cope with uncertain parameters associated with the gravity loading vector of the master and slave manipulators.Lyapunov-Krasovskii function is employed for three methods to establish asymptotic tracking property of the closed loop teleoperation systems.The stability analysis is derived for both symmetrical and unsymmetrical time varying delays in the forward and backward communication channel that connects the local and remote sites.Finally,evaluation results are presented to illustrate the efectiveness of the proposed design for real-time applications.
基金Project supported by the National Natural Science Foundation of China (No. 60374013) and the Natural Science Foundation of Zhejiang Province (No. M603217), China
文摘Permanent Magnet Synchronous Motor model can exhibit a variety of chaotic phenomena under some choices of system parameters and external input. Based on the property of passive system, the essential conditions were studied, by which Permanent Magnet Synchronous Motor chaotic system could be equivalent to passive system. Using Lyapunov stability theory, the convergence condition deciding the system's characters was discussed. In the convergence condition area, the equivalent passive system could be globally asymptotically stabilized by smooth state feedback.
基金Project supported by the Natural Science Foundation of Zhejiang Province (No. Y104414) and the Science and Technology Plan of Zhejiang Province (No. 2005C21084), China
文摘Passive system theory was applied to propose a new passive control method with nonlinear observer of the Permanent Magnet Synchronous Motor chaotic system. Through constructing a Lyapunov function, the subsystem of the Permanent Magnet Synchronous Motor chaotic system could be proved to be globally stable at the equilibrium point. Then a controller with smooth state feedback is designed so that the Permanent Magnet Synchronous Motor chaotic system can be equivalent to a passive system. To get the state variables of the controller, the nonlinear observer is also studied. It is found that the outputs of the nonlinear observer can approximate the state variables of the Permanent Magnet Synchronous Motor chaotic system if the system’s nonlinear function is a globally Lipschitz function. Simulation results showed that the equivalent passive system of Permanent Magnet Synchronous Motor chaotic system could be globally asymptotically stabilized by smooth state feedback in the observed parameter convergence condition area.
文摘Thermal comfort has a great impact on occupants’productivity and general well-being.Since people spend 80–90%of their time indoors,developing the tools and methods that enhance the thermal comfort for building are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new,dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall,and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).
文摘Thermal comfort has a great effect on occupants’productivity and general well-being.Since people spend 80-90%of their time indoors,developing the tools and methods that help in enhancing the thermal comfort for buildings are worth investigating.Previous studies have proved that using passive systems like Trombe walls and solar chimneys significantly enhanced thermal comfort in inside spaces despite that each system has a specific purpose within a specific climate condition.Hence,the main purpose of this study is to design and configure a new dual functional passive system,called a solar wall.The new system combines the Trombe wall and solar chimney,and it can cool or heat based on building needs.Simulation software,DesignBuilder,has been used to configure the Solar Wall and study its impact on indoor operative temperature for the base case.Using the new system,the simulation results were compared with those obtained in the base case and analyzed to determine the most efficient system design parameters and implementation method.The case that gave the best results for solar wall configuration was triple glazed glass and 0.1 cm copper as an absorber(case 11).The results show that using four units(case D)achieves longer thermal comfort levels:15 to 24 thermal hours during winter(compared to five hours maximum)and 10 to 19 comfort hours in summer(compared to zero).
基金National High-tech Research and Development Program of China (2009AA04Z412)"111" ProjectBUAA Fund of Graduate Education and Development
文摘Passive torque servo system (PTSS) simulates aerodynamic load and exerts the load on actuation system, but PTSS endures position coupling disturbance from active motion of actuation system, and this inherent disturbance is called extra torque. The most important issue for PTSS controller design is how to eliminate the influence of extra torque. Using backstepping technique, adaptive fuzzy torque control (AFTC) algorithm is proposed for PTSS in this paper, which reflects the essential characteristics of PTSS and guarantees transient tracking performance as well as final tracking accuracy. Takagi-Sugeno (T-S) fuzzy logic system is utilized to compensate parametric uncertainties and unstructured uncertainties. The output velocity of actuator identified model is introduced into AFTC aiming to eliminate extra torque. The closed-loop stability is studied using small gain theorem and the control system is proved to be semiglobally uniformly ultimately bounded. The proposed AFTC algorithm is applied to an electric load simulator (ELS), and the comparative experimental results indicate that AFTC controller is effective for PTSS.
文摘AIM To assess for passive expansion of sub-maximally dilated transjugular intrahepatic portosystemic shunts(TIPS) and compare outcomes with maximally dilated TIPS.METHODS Polytetrafluoroethylene covered TIPS(Viatorr) from July 2002 to December 2013 were retrospectively reviewed at two hospitals in a single institution. Two hundred and thirty patients had TIPS maximally dilated to 10 mm(m TIPS), while 43 patients who were at increased risk for hepatic encephalopathy(HE), based on clinical evaluation or low pre-TIPS portosystemic gradient(PSG), had 10 mm TIPS sub-maximally dilated to 8 mm(sm TIPS). Group characteristics(age, gender, Model for End-Stage Liver Disease score, post-TIPS PSG and clinical outcomes were compared between groups, including clinical success(ascites or varices), primary patency,primary assisted patency, and severe post-TIPS HE. A subset of fourteen patients with sm TIPS underwent follow-up computed tomography imaging after TIPS creation, and were grouped based on time of imaging(< 6 mo and > 6 mo). Change in diameter and crosssectional area were measured with 3D imaging software to evaluate for passive expansion.RESULTS Patient characteristics were similar between the sm TIPS and m TIPS groups, except for pre-TIPS portosystemic gradient, which was lower in the sm TIPS group(19.4 mm Hg ± 6.8 vs 22.4 mm Hg ± 7.1, P = 0.01). Primary patency and primary assisted patency between sm TIPS and m TIPS was not significantly different(P = 0.64 and 0.55, respectively). Four of the 55 patients(7%) with sm TIPS required TIPS reduction for severe refractory HE, while this occurred in 6 of the 218 patients(3%) with m TIPS(P = 0.12). For the 14 patients with follow-up computed tomography(CT) imaging, the median imaging follow-up was 373 d. There was an increase in median TIPS diameter, median percent diameter change, median area, and median percent area change in patients with CT follow-up greater than 6 mo after TIPS placement compared to follow-up within 6 mo(8.45 mm, 5.58%, 56.04 mm^2, and 11.48%, respectively, P = 0.01).CONCLUSION Passive expansion of sm TIPS does occur but clinical outcomes of sm TIPS and m TIPS were similar. Sub-maximal dilation can prevent complications related to overshunting in select patients.
基金supported by the National Key R&D Program of China(No.2019YFB1901100)the National Natural Science Foundation of China(No.11705138)the China National Postdoctoral Program for Innovative Talents(No.BX201600124)。
文摘The limited availability of studies on the natural convection heat transfer characteristics of fluoride salt has hindered progress in the design of passive residual heat removal systems(PRHRS)for molten salt reactors.This paper presents results from a numerical investigation of natural convection heat transfer characteristics of fluoride salt and heat pipes in the drain tank of a PRHRS.Simulation results are compared with experimental data,demonstrating the accuracy of the calculation methodology.Temperature distribution of fluoride salt and heat transfer characteristics are obtained and analyzed.The radial temperature of liquid fluoride salt in the drain tank shows a uniform distribution,while temperatures increase with increase in axial height from the bottom to the top of the drain tank.In addition,natural convection intensity increases with increase in height of the heat pipes in the tank.Spacing between heat pipes has no obvious effect on the natural convection heat transfer coefficient.This study will contribute to the design of passive heat removal systems for advanced nuclear reactors.
文摘This paper investigates the synchronization of a fractional order hyperchaotic system using passive control. A passive controller is designed, based on the properties of a passive system. Then the synchronization between two fractional order hyperchaotic systems under different initial conditions is realized, on the basis of the stability theorem for fractional order systems. Numerical simulations and circuitry simulations are presented to verify the analytical results.
基金Project supported by the National Natural Science Foundation of China （Grant No 60374013）, the Natural Science Foundation of Zhejiang Province （Grant Nos M603217 and Y104414）.
文摘In this paper we present a new simple controller for a chaotic system, that is, the Newton-Leipnik equation with two strange attractors： the upper attractor （UA） and the lower attractor （LA）. The controller design is based on the passive technique. The final structure of this controller for original stabilization has a simple nonlinear feedback form. Using a passive method, we prove the stability of a closed-loop system. Based on the controller derived from the passive principle, we investigate three different kinds of chaotic control of the system, separately： the original control forcing the chaotic motion to settle down to the origin from an arbitrary position of the phase space; the chaotic intra-attractor control for stabilizing the equilibrium points only belonging to the upper chaotic attractor or the lower chaotic one, and the inter-attractor control for compelling the chaotic oscillation from one basin to another one. Both theoretical analysis and simulation results verify the validity of the suggested method.
基金This work was supported by the National Natu-ral Science Foundation of China(No.U20B2038,No.61901520,No.61871398 and No.61931011),the Natural Science Foundation for Distinguished Young Scholars of Jiangsu Province(No.BK20190030),and the National Key R&D Program of China under Grant 2018YFB1801103.
文摘In spectrum sharing systems,locating mul-tiple radiation sources can efficiently find out the in-truders,which protects the shared spectrum from ma-licious jamming or other unauthorized usage.Com-pared to single-source localization,simultaneously lo-cating multiple sources is more challenging in prac-tice since the association between measurement pa-rameters and source nodes are not known.More-over,the number of possible measurements-source as-sociations increases exponentially with the number of sensor nodes.It is crucial to discriminate which measurements correspond to the same source before localization.In this work,we propose a central-ized localization scheme to estimate the positions of multiple sources.Firstly,we develop two computa-tionally light methods to handle the unknown RSS-AOA measurements-source association problem.One method utilizes linear coordinate conversion to com-pute the minimum spatial Euclidean distance sum-mation of measurements.Another method exploits the long-short-term memory(LSTM)network to clas-sify the measurement sequences.Then,we propose a weighted least squares(WLS)approach to obtain the closed-form estimation of the positions by linearizing the non-convex localization problem.Numerical re-sults demonstrate that the proposed scheme could gain sufficient localization accuracy under adversarial sce-narios where the sources are in close proximity and the measurement noise is strong.
基金supported partly by the National Natural Science Foundation of China(60574001)the Program for New Century Excellent Talents in University(050485)the Program for Innovative Research Team of Jiangnan University.
文摘The exponential passive filtering problem for a class of nonlinear Markov jump systems with uncertainties and time-delays is studied. The uncertain parameters are assumed unknown but norm bounded, and the nonlinearities satisfy the quadratic condition. Based on the passive filtering theory, the sufficient condition for the existence of the mode-dependent passive filter is given by analyzing the reconstructed observer system. By using the appropriate Lyapnnov-Krasovskii function and applying linear matrix inequalities, the design scheme of the passive filter is derived and described as an optimization one. The presented exponential passive filter makes the error dynamic systems exponentially stochastically stable for all the admissible uncertainties, time-delays and nonlinearities, has the better abilities of state tracking and satisfies the given passive norm index. Simulation results demonstrate the validity of the proposed approach.
文摘Synchronization of a hyperchaotic Lorenz system is discussed using passive control. Based on the properties of a passive system, a passive controller is designed and the synchronization between two hyperchaotic Lorenz systems under different initial conditions is realized. Simulation results show the proposed synchronization method to be effective.
