In this paper, we consider the positive semidefinite solution of the matrix equation (AT X A, BT X B) - (C, D). A necessary and sufficient condition for the existence of such solution is derived using the generalized ...In this paper, we consider the positive semidefinite solution of the matrix equation (AT X A, BT X B) - (C, D). A necessary and sufficient condition for the existence of such solution is derived using the generalized singular value decomposition.The general forms of positive semidefinite solution are given.展开更多
For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable mag...For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.展开更多
The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvi...The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvis and breast treatment in MEIH （Middle East Institute of Health）. The present work is carried out on 30-472 and 30-473 diode detectors irradiated by 4 and 15MV photon beams of a medical linear accelerator Synergy from ELEKTA. Dose computation is performed with Pinnacle 7.4 k treatment planning system. First, an estimation of the uncertainties in a simple geometric case, using a water-equivalent solid phantom is done. Secondly, each treatment parameter such as field size, beam angle, beam modifiers and source-skin distance is evaluated in order to simulate the conformal radiation treatments used in the present institution for the main anatomical sites. Interpretation of entrance dose in-vivo measurements requires the determination of appropriate tolerance levels. Indeed, the authors found that the 5% action level proposed in the literature underestimates the uncertainties in the treatment process. A method for the evaluation of tolerance/action levels related to the different anatomical sites is developed. By the end of the present study the authors have developed an integrated monitoring system that offers accurate information about the dose received by patients.展开更多
A risk in the prices of fossil fuels is a major concern to importing countries of them. This study analyzes the risk of an increase in the cost for Japanese electric utility sector during the period 1978-2007 consider...A risk in the prices of fossil fuels is a major concern to importing countries of them. This study analyzes the risk of an increase in the cost for Japanese electric utility sector during the period 1978-2007 considering the uncertainty in the prices of fossil fuels. The mean-semivariance model, which uses an upper semivariance as an index of the risk, is adopted for the purpose. The result confirms that the semivariance is the better index of the risk than the variance. Furether, the semivariance is decomposed into two factors; the risk caused by price changes in an individual fossil fuel source and the risk caused by correlations among the changes in the prices of fossil fuel sources. The former has been kept at a low level as it appears to be easy to estimate, while the latter has not been maintained at the lowest level as it appears to be difficult to estimate. The Japanese electric utility sector followed the minimum-risk fossil fuel mix up until 2001, but discontinued the same post 2001.展开更多
This paper presents the sufficient conditions for the exponential stability of linear or semi-linear stochastic delay equations with time-varying norm bounded parameter uncertainties.Exponen-tial estimates for the sol...This paper presents the sufficient conditions for the exponential stability of linear or semi-linear stochastic delay equations with time-varying norm bounded parameter uncertainties.Exponen-tial estimates for the solutions are also obtained by using a modified Lyapunov-Krasovski functional.These conditions can be tested numerically using interior point algorithms.展开更多
基金supported by the National Statistical Science Research Project(Grant No.2020LY010)the Open Research Fund of Key Laboratory of Advanced Theory and Application in Statistics and Data Science-MOE,ECNUthe Fundamental Research Funds for the Central Universities.
基金Partially supported by the National Natural Science Foundation of China(No10071035) and the Doctor Foundation of Hunan Normal University.
文摘In this paper, we consider the positive semidefinite solution of the matrix equation (AT X A, BT X B) - (C, D). A necessary and sufficient condition for the existence of such solution is derived using the generalized singular value decomposition.The general forms of positive semidefinite solution are given.
基金National Key Lab for Electronic Measurement and Technology,North University of China(No.9140C120401080C12)
文摘For the test of rotation speed of high spinning projectile, the general formula of the motional electromotive force （MEMF） of planar magnetic induction coil （PMIC） is derived in case of 3D rotation in a stable magnetic field. Under a reasona-ble assumption, the MEMF of PMIC is simplified after the aforementioned general formula is used to calculate high spinning PMIC in the geomagnetic field environment. The determination approach of half-cycle is discussed and the method of rotation speed test is studied, and a test is conducted in the paper. The rotation speed curve obtained by the approach in this paper is consistent with the curve by telemetry.
文摘The purpose of the present study is to evaluate the uncertainties of in vivo dosimetry measured with diode detectors for conformal radiation therapy techniques in order to define appropriate tolerance levels for pelvis and breast treatment in MEIH （Middle East Institute of Health）. The present work is carried out on 30-472 and 30-473 diode detectors irradiated by 4 and 15MV photon beams of a medical linear accelerator Synergy from ELEKTA. Dose computation is performed with Pinnacle 7.4 k treatment planning system. First, an estimation of the uncertainties in a simple geometric case, using a water-equivalent solid phantom is done. Secondly, each treatment parameter such as field size, beam angle, beam modifiers and source-skin distance is evaluated in order to simulate the conformal radiation treatments used in the present institution for the main anatomical sites. Interpretation of entrance dose in-vivo measurements requires the determination of appropriate tolerance levels. Indeed, the authors found that the 5% action level proposed in the literature underestimates the uncertainties in the treatment process. A method for the evaluation of tolerance/action levels related to the different anatomical sites is developed. By the end of the present study the authors have developed an integrated monitoring system that offers accurate information about the dose received by patients.
文摘A risk in the prices of fossil fuels is a major concern to importing countries of them. This study analyzes the risk of an increase in the cost for Japanese electric utility sector during the period 1978-2007 considering the uncertainty in the prices of fossil fuels. The mean-semivariance model, which uses an upper semivariance as an index of the risk, is adopted for the purpose. The result confirms that the semivariance is the better index of the risk than the variance. Furether, the semivariance is decomposed into two factors; the risk caused by price changes in an individual fossil fuel source and the risk caused by correlations among the changes in the prices of fossil fuel sources. The former has been kept at a low level as it appears to be easy to estimate, while the latter has not been maintained at the lowest level as it appears to be difficult to estimate. The Japanese electric utility sector followed the minimum-risk fossil fuel mix up until 2001, but discontinued the same post 2001.
基金Supported by the National Natural Science Foundation of China under Grant Nos. 10801056 and 10826095
文摘This paper presents the sufficient conditions for the exponential stability of linear or semi-linear stochastic delay equations with time-varying norm bounded parameter uncertainties.Exponen-tial estimates for the solutions are also obtained by using a modified Lyapunov-Krasovski functional.These conditions can be tested numerically using interior point algorithms.
