In this paper, several sets of observing system simulation experiments (OSSEs) were designed for three typhoon cases to determine whether or not the additional observation data in the sensitive regions identified by c...In this paper, several sets of observing system simulation experiments (OSSEs) were designed for three typhoon cases to determine whether or not the additional observation data in the sensitive regions identified by conditional nonlinear optimal perturbations (CNOPs) could improve the short-range forecast of typhoons. The results show that the CNOPs capture the sensitive regions for typhoon forecasts, which implies that conducting additional observation in these specific regions and eliminating initial errors could reduce forecast errors. It is inferred from the results that dropping sondes in the CNOP sensitive regions could lead to improvements in typhoon forecasts.展开更多
Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output ...Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function(RIMPDF) and Regional Importance Measure based on Cumulative Distribution Function(RIMCDF),are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.展开更多
Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type sil...Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors(R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator(SOI) wafer by micro electromechanical system(MEMS) technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity(TCS) for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.展开更多
In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and...In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and stresses.Magnetization curves were also achieved at different stresses.Influence of the applied stresses on the hysteresis loops was investigated.The stress sensitive region and linear stress sensitive region of magnetic induction were determined for the model specimen according to the experimental data.The dependence relation of magnetic induction versus applied stresses was established,and the optimum magnetic field was determined in the stress sensitive range of magnetic induction,which builds a basis for nondestructive testing(NDT) of stress with the total magnetic flux for steel structure.Based on modified Jiles-Atherton's model of magnetic hysteresis,the hysteresis loop for Q235 steel 4-mm diameter model specimen was numerically simulated,which was well consistent with the experimental results.展开更多
Detailed investigations on the notch technique are performed on ideal data generated by the optical model potential parameters extracted from the 16O+208spb system at the laboratory energy of 129.5 MeV, to study the ...Detailed investigations on the notch technique are performed on ideal data generated by the optical model potential parameters extracted from the 16O+208spb system at the laboratory energy of 129.5 MeV, to study the sensitivities of this technique to the model parameters as well as the experimental data. It is found that for the perturbation parameters, a sufficiently large reduced fraction and an appropriate small perturbation width are necessary to determine the accurate radial sensitivity; while for the potential parameters, almost no dependence was observed. For the experimental measurements, the number of data points has little influence for heavy target systems, and the relative inner information of the nuclear potential can be derived when the measurement is extended to a lower cross section.展开更多
Identifying source information after river chemical spill occurrences is critical for emergency responses.However,the inverse uncertainty characteristics of this kind of pollution source inversion problem have not yet...Identifying source information after river chemical spill occurrences is critical for emergency responses.However,the inverse uncertainty characteristics of this kind of pollution source inversion problem have not yet been clearly elucidated.To fill this gap,stochastic analysis approaches,including a regional sensitivity analysis method,identifiability plot and perturbation methods,were employed to conduct an empirical investigation on generic inverse uncertainty characteristics under a well-accepted uncertainty analysis framework.Case studies based on field tracer experiments and synthetic numerical tracer experiments revealed several new rules.For example,the release load can be most easily inverted,and the source location is responsible for the largest uncertainty among the source parameters.The diffusion and convection processes are more sensitive than the dilution and pollutant attenuation processes to the optimization of objective functions in terms of structural uncertainty.The differences among the different objective functions are smaller for instantaneous release than for continuous release cases.Small monitoring errors affect the inversion results only slightly,which can be ignored in practice.Interestingly,the estimated values of the release location and time negatively deviate from the real values,and the extent is positively correlated with the relative size of the mixing zone to the objective river reach.These new findings improve decision making in emergency responses to sudden water pollution and guide the monitoring network design.展开更多
基金sponsored by the National Natural Science Foundation of China (Grant Nos. 40830955 and 40821092)the Project of China Meteorological Administration (Grant No. GYHY200906009)
文摘In this paper, several sets of observing system simulation experiments (OSSEs) were designed for three typhoon cases to determine whether or not the additional observation data in the sensitive regions identified by conditional nonlinear optimal perturbations (CNOPs) could improve the short-range forecast of typhoons. The results show that the CNOPs capture the sensitive regions for typhoon forecasts, which implies that conducting additional observation in these specific regions and eliminating initial errors could reduce forecast errors. It is inferred from the results that dropping sondes in the CNOP sensitive regions could lead to improvements in typhoon forecasts.
基金supported by the National Natural Science Foundation of China(No.NSFC51608446)the Fundamental Research Fund for Central Universities of China(No.3102016ZY015)
文摘Traditional Global Sensitivity Analysis(GSA) focuses on ranking inputs according to their contributions to the output uncertainty.However,information about how the specific regions inside an input affect the output is beyond the traditional GSA techniques.To fully address this issue,in this work,two regional moment-independent importance measures,Regional Importance Measure based on Probability Density Function(RIMPDF) and Regional Importance Measure based on Cumulative Distribution Function(RIMCDF),are introduced to find out the contributions of specific regions of an input to the whole output distribution.The two regional importance measures prove to be reasonable supplements of the traditional GSA techniques.The ideas of RIMPDF and RIMCDF are applied in two engineering examples to demonstrate that the regional moment-independent importance analysis can add more information concerning the contributions of model inputs.
基金supported by the National Natural Science Foundation of China(No.61471159)the Natural Science Foundation of Heilongjiang Province(No.F201433)+1 种基金the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.2015018)the Special Funds for Science and Technology Innovation Talents of Harbin in China(No.2016RAXXJ016)
文摘Based on the asymmetric base region transistor, a pressure sensor with temperature compensation circuit is proposed in this paper. The pressure sensitive structure of the proposed sensor is constructed by a C-type silicon cup and a Wheatstone bridge with four piezoresistors(R_1, R_2, R_3 and R_4/locating on the edge of a square silicon membrane. The chip was designed and fabricated on a silicon on insulator(SOI) wafer by micro electromechanical system(MEMS) technology and bipolar transistor process. When the supply voltage is 5.0 V, the corresponding temperature coefficient of the sensitivity(TCS) for the sensor before and after temperature compensation are -1862 and -1067 ppm/℃, respectively. Through varying the ratio of the base region resistances r_1 and r_2, the TCS for the sensor with the compensation circuit is -127 ppm/℃. It is possible to use this compensation circuit to improve the temperature characteristics of the pressure sensor.
基金the National Natural Science Foundation of China(Nos.51108035,51178388 and 10972168)the Natural Science Basic Research Plan in Shaanxi Province of China(No.2010JQ7006)+1 种基金the China Postdoctoral Science Foundation(No.20100481313)the Special Fund for Basic Scientific Research of Central College of China(No.CHD2012ZD012)
文摘In this study,magnetomechanical coupling tests were performed on Q235 solid round steel model specimens in NIM-200HF magnetomechanical coupling equipment.Hysteresis loops were obtained in different magnetic fields and stresses.Magnetization curves were also achieved at different stresses.Influence of the applied stresses on the hysteresis loops was investigated.The stress sensitive region and linear stress sensitive region of magnetic induction were determined for the model specimen according to the experimental data.The dependence relation of magnetic induction versus applied stresses was established,and the optimum magnetic field was determined in the stress sensitive range of magnetic induction,which builds a basis for nondestructive testing(NDT) of stress with the total magnetic flux for steel structure.Based on modified Jiles-Atherton's model of magnetic hysteresis,the hysteresis loop for Q235 steel 4-mm diameter model specimen was numerically simulated,which was well consistent with the experimental results.
基金Supported by National Natural Science Foundation of China(11375268,11475263,U1432246 and U1432127)the National Key Basic Research Program of China(2013CB834404)
文摘Detailed investigations on the notch technique are performed on ideal data generated by the optical model potential parameters extracted from the 16O+208spb system at the laboratory energy of 129.5 MeV, to study the sensitivities of this technique to the model parameters as well as the experimental data. It is found that for the perturbation parameters, a sufficiently large reduced fraction and an appropriate small perturbation width are necessary to determine the accurate radial sensitivity; while for the potential parameters, almost no dependence was observed. For the experimental measurements, the number of data points has little influence for heavy target systems, and the relative inner information of the nuclear potential can be derived when the measurement is extended to a lower cross section.
基金funded by the China Postdoctoral Science Foundation(Grant No.2014M551249)the National Natural Science Foundation of China(Grant No.51509061)support was provided by the Southern University of Science and Technology(Grant No.G01296001).
文摘Identifying source information after river chemical spill occurrences is critical for emergency responses.However,the inverse uncertainty characteristics of this kind of pollution source inversion problem have not yet been clearly elucidated.To fill this gap,stochastic analysis approaches,including a regional sensitivity analysis method,identifiability plot and perturbation methods,were employed to conduct an empirical investigation on generic inverse uncertainty characteristics under a well-accepted uncertainty analysis framework.Case studies based on field tracer experiments and synthetic numerical tracer experiments revealed several new rules.For example,the release load can be most easily inverted,and the source location is responsible for the largest uncertainty among the source parameters.The diffusion and convection processes are more sensitive than the dilution and pollutant attenuation processes to the optimization of objective functions in terms of structural uncertainty.The differences among the different objective functions are smaller for instantaneous release than for continuous release cases.Small monitoring errors affect the inversion results only slightly,which can be ignored in practice.Interestingly,the estimated values of the release location and time negatively deviate from the real values,and the extent is positively correlated with the relative size of the mixing zone to the objective river reach.These new findings improve decision making in emergency responses to sudden water pollution and guide the monitoring network design.