Under maids loss, tall paper dicusses the admissibility of homgeneous or nonhomgeneous linear estimators of regresaion coefficient of multivarate linear model in some common classes of estimators, the necessary and su...Under maids loss, tall paper dicusses the admissibility of homgeneous or nonhomgeneous linear estimators of regresaion coefficient of multivarate linear model in some common classes of estimators, the necessary and sufficient conditions are obtained.The results indicate that the admissibility of linear estimetors in multiate linear model is different from the admiedbility of linear estimators in Gauss-Markoff model.展开更多
The necessary and sufficient conditions for a linear estimator of a linear estimable functionof regression coefficients in a general fixed effects linear model with the assumptions of normality to beadmissible in the ...The necessary and sufficient conditions for a linear estimator of a linear estimable functionof regression coefficients in a general fixed effects linear model with the assumptions of normality to beadmissible in the class of all estimators under matrix liss function are given.For a general randomeffects or mixted effects linear model the necessary and sufficient conditions are obtained too.展开更多
For the general fixed effects linear model:Y=Xτ+ε,ε～N（0,V）（or N（0,σ<sup>2</sup>V））,V≥0,we obtain the necessary and sufficient condition for LY+α to be admissible for Sτ in the class of allest...For the general fixed effects linear model:Y=Xτ+ε,ε～N（0,V）（or N（0,σ<sup>2</sup>V））,V≥0,we obtain the necessary and sufficient condition for LY+α to be admissible for Sτ in the class of allestimators under matrix loss function（d-Sτ）（d-Sτ）′;for the general random effects linear model:Y=Xβ+ε,（?）where （?）=XV<sub>11</sub>X′+XV<sub>12</sub>+V<sub>21</sub>X′+V<sub>22</sub>≥0,we also obtain the necessary and sufficient condition for LY+α to be admissible for Sα+Qβin the class of all estimators under matrix loss function（d-Sα-Qβ）（d-Sα-Qβ）′.展开更多
In this paper,the definitions of Bayes estimator,minimax estimator,minimumrisk equivariant estimator and admissible estimator under the general matrix loss functionare given.Several results on estimation of parameters...In this paper,the definitions of Bayes estimator,minimax estimator,minimumrisk equivariant estimator and admissible estimator under the general matrix loss functionare given.Several results on estimation of parameters with the ordinary loss function areextended to the case of the matrix loss function.展开更多
A stability problem of the linear networked control systems(NCSs) with multisensor having differen data missing rates is investigated in this paper.Each sensor of the multiple sensor-controller communication channels ...A stability problem of the linear networked control systems(NCSs) with multisensor having differen data missing rates is investigated in this paper.Each sensor of the multiple sensor-controller communication channels is assumed to have an individual stochastic data missing rate.The stochastic data missing is described by a Bernoulli binary distribution.Sufficient conditions are given for the closed-loop linear NCS which is exponentially stable in the mean square sense as the existence of random multiple data missing.The stability problem could b disposed by the MATLAB linear matrix inequality(LMI) tool easily.A simulation case is provided to illustrat the validity of the presented LMI approach.展开更多
This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are ...This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are introduced to model the interconnected systems as discrete time-space multidimensional linear systems with Markovian jumping parameters which reflect the state of communication channels. To ensure the whole system＇s well-posedness and mean square stability for a given packet loss rate, a condition is derived through analysis. Then a procedure of designing distributed dynamic output feedback controllers is proposed. The controllers have the same structure as the plants and are solved within the linear matrix inequality （LMI） framework. Finally, we apply these results to study the effect of communication losses on the multiple vehicle platoon control system, which further illustrates the effectiveness of the proposed model and method.展开更多
Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified...Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified four-microphone standing-wave (impedance) tube for specimens with different lengths, 15 and 30 mm. Each cylinder tube is tested filled with one of the fluids at a time. The fluids are air, water, motor oil and a nanoparticle fluid (in absence of magnetic field). The effects of the cylinder length (thickness), impedance tube terminations, and the containing fluid are discussed. The increasing of the thickness led to an increase of the TL values and a decrease in resonance frequencies. Also, the addition of liquid middle layer led to considerable increase of the TL.展开更多
The present work includes the study of the dynamic properties of the nanocomposites specimens. The dynamic properties of A356/Al2O3 nanocomposites were investigated through different fabrication conditions. The A356/A...The present work includes the study of the dynamic properties of the nanocomposites specimens. The dynamic properties of A356/Al2O3 nanocomposites were investigated through different fabrication conditions. The A356/Al2O3 nanocomposites specimens were fabricated using a combination between the rheocasting and squeeze casting routes. The composites were reinforced with Al2O3 particulates of 60 and 200 nm and different volume fractions up to 5 vol.%. The dynamic properties of the A356/Al2O3 nanocomposites were investigated through measuring the dynamic properties of specimens. Free vibration method is used to measure frequency response (fn ), and damping factor (ξ). The viscoelastic properties such as loss factor η, storage modulus (E'), and loss modulus (E") were obtained. The results concluded that, the dynamic properties of nanocomposites were improved by increasing the volume fractions of nanoparticulates and decreasing the nanoparticulates size. The results indicated also that, the damping factor, and the related parameters (η, E' and E") was strongly affected by increasing both volume fraction and the particulates.展开更多
焦炭作为高炉内唯一的骨架支柱,其劣化行为对高炉的透气透液性及冶炼能耗都有着十分重要的影响。基于焦炭的非均匀劣化特征及其与高炉透气性的关系,采用多孔传质反应理论方程与耦合叠加方法构建了以焦炭体积表观速率常数kV与孔扩散系数D...焦炭作为高炉内唯一的骨架支柱,其劣化行为对高炉的透气透液性及冶炼能耗都有着十分重要的影响。基于焦炭的非均匀劣化特征及其与高炉透气性的关系,采用多孔传质反应理论方程与耦合叠加方法构建了以焦炭体积表观速率常数kV与孔扩散系数Deff为核心的焦炭非均匀劣化行为评价模型,以准确评价高炉内焦炭的劣化行为,为完善现有的焦炭质量评价体系提供帮助。根据焦炭气孔分布及其劣化演变特征,采用SEM(scanning electron microscope)、压汞法和X衍射分析等方法准确测定并推算了不同条件下焦炭孔扩散系数的大小及变化,得出了焦炭内部劣化反应梯度的变化规律,并由此计算和分析了焦炭的高温劣化行为及其粒度分布特征,提出了以粒度分布集中度作为评价焦炭劣化行为的重要指标。最后通过对模型结构与模型参数的调整与修正,对实际焦炭试验数据与模型预测结果进行了对比验证,计算结果表明,模型预测结果与试验结果具有较高的吻合度,且模型实现了对不同初始粒径的焦炭在不同劣化时间内粒度分布集中度的合理预测,通过该模型能更准确地评判焦炭质量对高炉透气性的影响,从而为优化焦炭质量评价体系提供帮助。展开更多
文摘Under maids loss, tall paper dicusses the admissibility of homgeneous or nonhomgeneous linear estimators of regresaion coefficient of multivarate linear model in some common classes of estimators, the necessary and sufficient conditions are obtained.The results indicate that the admissibility of linear estimetors in multiate linear model is different from the admiedbility of linear estimators in Gauss-Markoff model.
基金The work is supported by the Science Fund R850020 of the Academia Sinica
文摘The necessary and sufficient conditions for a linear estimator of a linear estimable functionof regression coefficients in a general fixed effects linear model with the assumptions of normality to beadmissible in the class of all estimators under matrix liss function are given.For a general randomeffects or mixted effects linear model the necessary and sufficient conditions are obtained too.
文摘For the general fixed effects linear model:Y=Xτ+ε,ε～N（0,V）（or N（0,σ<sup>2</sup>V））,V≥0,we obtain the necessary and sufficient condition for LY+α to be admissible for Sτ in the class of allestimators under matrix loss function（d-Sτ）（d-Sτ）′;for the general random effects linear model:Y=Xβ+ε,（?）where （?）=XV<sub>11</sub>X′+XV<sub>12</sub>+V<sub>21</sub>X′+V<sub>22</sub>≥0,we also obtain the necessary and sufficient condition for LY+α to be admissible for Sα+Qβin the class of all estimators under matrix loss function（d-Sα-Qβ）（d-Sα-Qβ）′.
文摘In this paper,the definitions of Bayes estimator,minimax estimator,minimumrisk equivariant estimator and admissible estimator under the general matrix loss functionare given.Several results on estimation of parameters with the ordinary loss function areextended to the case of the matrix loss function.
基金the National Natural Science Foundation of China(No.U1204515)the Foundation of Young Teachers in Colleges and Universities of Shanghai(No.ZZSDJ12002)the Shanghai Municipal Natural Science Foundation(No.14ZR1417200)
文摘A stability problem of the linear networked control systems(NCSs) with multisensor having differen data missing rates is investigated in this paper.Each sensor of the multiple sensor-controller communication channels is assumed to have an individual stochastic data missing rate.The stochastic data missing is described by a Bernoulli binary distribution.Sufficient conditions are given for the closed-loop linear NCS which is exponentially stable in the mean square sense as the existence of random multiple data missing.The stability problem could b disposed by the MATLAB linear matrix inequality(LMI) tool easily.A simulation case is provided to illustrat the validity of the presented LMI approach.
文摘This paper deals with analysis and synthesis problems of spatially interconnected systems where communicated information may get lost between subsystems. Spatial shift operator and temporal forward shift operator are introduced to model the interconnected systems as discrete time-space multidimensional linear systems with Markovian jumping parameters which reflect the state of communication channels. To ensure the whole system＇s well-posedness and mean square stability for a given packet loss rate, a condition is derived through analysis. Then a procedure of designing distributed dynamic output feedback controllers is proposed. The controllers have the same structure as the plants and are solved within the linear matrix inequality （LMI） framework. Finally, we apply these results to study the effect of communication losses on the multiple vehicle platoon control system, which further illustrates the effectiveness of the proposed model and method.
文摘Transmission Loss (TL) of a glass cylinder tube containing a fluid is studied experimentally. This test specimen represents a typical double layer panel including a fluid. The tests are carried out by using a modified four-microphone standing-wave (impedance) tube for specimens with different lengths, 15 and 30 mm. Each cylinder tube is tested filled with one of the fluids at a time. The fluids are air, water, motor oil and a nanoparticle fluid (in absence of magnetic field). The effects of the cylinder length (thickness), impedance tube terminations, and the containing fluid are discussed. The increasing of the thickness led to an increase of the TL values and a decrease in resonance frequencies. Also, the addition of liquid middle layer led to considerable increase of the TL.
文摘The present work includes the study of the dynamic properties of the nanocomposites specimens. The dynamic properties of A356/Al2O3 nanocomposites were investigated through different fabrication conditions. The A356/Al2O3 nanocomposites specimens were fabricated using a combination between the rheocasting and squeeze casting routes. The composites were reinforced with Al2O3 particulates of 60 and 200 nm and different volume fractions up to 5 vol.%. The dynamic properties of the A356/Al2O3 nanocomposites were investigated through measuring the dynamic properties of specimens. Free vibration method is used to measure frequency response (fn ), and damping factor (ξ). The viscoelastic properties such as loss factor η, storage modulus (E'), and loss modulus (E") were obtained. The results concluded that, the dynamic properties of nanocomposites were improved by increasing the volume fractions of nanoparticulates and decreasing the nanoparticulates size. The results indicated also that, the damping factor, and the related parameters (η, E' and E") was strongly affected by increasing both volume fraction and the particulates.
文摘焦炭作为高炉内唯一的骨架支柱,其劣化行为对高炉的透气透液性及冶炼能耗都有着十分重要的影响。基于焦炭的非均匀劣化特征及其与高炉透气性的关系,采用多孔传质反应理论方程与耦合叠加方法构建了以焦炭体积表观速率常数kV与孔扩散系数Deff为核心的焦炭非均匀劣化行为评价模型,以准确评价高炉内焦炭的劣化行为,为完善现有的焦炭质量评价体系提供帮助。根据焦炭气孔分布及其劣化演变特征,采用SEM(scanning electron microscope)、压汞法和X衍射分析等方法准确测定并推算了不同条件下焦炭孔扩散系数的大小及变化,得出了焦炭内部劣化反应梯度的变化规律,并由此计算和分析了焦炭的高温劣化行为及其粒度分布特征,提出了以粒度分布集中度作为评价焦炭劣化行为的重要指标。最后通过对模型结构与模型参数的调整与修正,对实际焦炭试验数据与模型预测结果进行了对比验证,计算结果表明,模型预测结果与试验结果具有较高的吻合度,且模型实现了对不同初始粒径的焦炭在不同劣化时间内粒度分布集中度的合理预测,通过该模型能更准确地评判焦炭质量对高炉透气性的影响,从而为优化焦炭质量评价体系提供帮助。
