This paper introduces the class of seasonal fractionally integrated autoregressive<span style="font-family:Verdana;"> moving average</span><span style="font-family:Verdana;">-<...This paper introduces the class of seasonal fractionally integrated autoregressive<span style="font-family:Verdana;"> moving average</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">generalized conditional heteroskedastisticty (SARFIMA-</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">GARCH) models, with level shift type intervention that are capable of capturing simultaneously four key features of time series: seasonality, long range dependence, volatility and level shift. The main focus is on modeling seasonal level shift (SLS) in fractionally integrated and volatile processes. A natural extension of the seasonal level shift detection test of the mean for a realization of time series satisfying SLS-SARFIMA and SLS-GARCH models w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> derived. Test statistics that are useful to examine if seasonal level shift in a</span><span style="font-family:Verdana;">n</span><span style="font-family:Verdana;"> SARFIMA-GARCH model </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> statistically plausible were established. Estimation of SLS-SARFIMA and SLS-GARCH parameters w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> also considered.</span>展开更多
We investigate the energy-level shift of a hydrogen atom in a two-dimensional optical microcavity, where there exists a Bose-Einstein condensation of photons. It is found that below the critical temperature Tc, the en...We investigate the energy-level shift of a hydrogen atom in a two-dimensional optical microcavity, where there exists a Bose-Einstein condensation of photons. It is found that below the critical temperature Tc, the energy-level shift of the bound electron is dependent on temperature, and it is a monotonically increasing function of the absolute temperature T. Especially, at the absolute zero temperature, the energy-level shift entirely comes from the Lamb shift, and the atom can be treated approximately, that is, in vacuum.展开更多
In this paper, we introduce the class of autoregressive fractionally integrated moving average-generalized autoregressive conditional heteroskedasticity?(ARFIMA-GARCH) models with level shift type intervention that ar...In this paper, we introduce the class of autoregressive fractionally integrated moving average-generalized autoregressive conditional heteroskedasticity?(ARFIMA-GARCH) models with level shift type intervention that are capable of capturing three key features of time series: long range dependence, volatility?and level shift. The main concern is on detection of mean and volatility level shift in a fractionally integrated time series with volatility. We will denote such a time series as level shift autoregressive fractionally integrated moving average (LS-ARFIMA) and level shift generalized autoregressive conditional heteroskedasticity (LS-GARCH). Test statistics that are useful to examine if mean and volatility level shifts are present in an autoregressive fractionally integrated moving average-generalized autoregressive conditional heteroskedasticity (ARFIMA-GARCH) model are derived. Quasi maximum likelihood estimation of the model is also considered.展开更多
The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most s...The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most significant applications of metal oxides is heterogeneous catalysis,which represents a pivotal technology in industrial production on a global scale.Catalysts serve as the primary enabling agents for chemical reactions,and among the plethora of catalysts,metal oxides including magnesium oxide(MgO),ceria(CeO_(2))and titania(TiO_(2)),have been identified to be particularly effective in catalyzing a variety of reactions[1].Theoretical calculations based on density functional theory(DFT)and a multitude of other quantum chemistry methods have proven invaluable in elucidating the mechanisms of metal-oxide-catalyzed reactions,thereby facilitating the design of high-performance catalysts[2].展开更多
A novel level shift circuit featuring with high dV/dt noise immunity and improved negative V_S capacity is proposed in this paper.Compared with the conventional structure,the proposed circuit adopting two cross-couple...A novel level shift circuit featuring with high dV/dt noise immunity and improved negative V_S capacity is proposed in this paper.Compared with the conventional structure,the proposed circuit adopting two cross-coupled PMOS transistors realizes the selective filtering ability by exploiting the path which filters out the noise introduced by the dV/dt.In addition,a differential noise cancellation circuit is proposed to enhance the noise immunity further.Meanwhile,the negative V_S capacity is improved by unifying the detected reference voltage and the logic block＇s threshold voltage.A high voltage half bridge gate drive IC adopting the presented structure is experimentally realized by using a usual 600 V BCD process and achieves the stable operation up to 65 V/ns of the dV/dt characteristics.展开更多
In this paper, we proposed a metric to measure the shift invariance of the three different contourlet transforms. And then, using the same structure texture image retrieval system which use subband coefficients energy...In this paper, we proposed a metric to measure the shift invariance of the three different contourlet transforms. And then, using the same structure texture image retrieval system which use subband coefficients energy, standard deviation and kurtosis features with Canberra distance, we gave a comparison of their texture description abilities. Experimental results show that contourlet-2.3 texture image retrieval system has almost retrieval rates with non-sub sampled contourlet system;the two systems have better retrieval results than the original contourlet retrieval system. On the other hand, for the relatively lower redundancy, we recommend using contourlet- 2.3 as texture description transform.展开更多
In modern fiction translation, translators occasionally encounter multitudinous problems, which need to be solved by various translation tactics. The paper hereof aims to adopt John Catford's shifts theory to anal...In modern fiction translation, translators occasionally encounter multitudinous problems, which need to be solved by various translation tactics. The paper hereof aims to adopt John Catford's shifts theory to analyze the tactics used to solve the problems in fiction translation on syntactical level via translating Best Kept Secret.展开更多
Mean Shift跟踪算法在目标尺度变化大和被遮挡时存在较大的缺陷。针对这一问题,提出了一种基于多级正方形匹配的自适应带宽选择和分块抗遮挡的目标跟踪算法。该算法采用目标中心点的离散程度和增量试探法计算出可能的变化尺度,然后采用...Mean Shift跟踪算法在目标尺度变化大和被遮挡时存在较大的缺陷。针对这一问题,提出了一种基于多级正方形匹配的自适应带宽选择和分块抗遮挡的目标跟踪算法。该算法采用目标中心点的离散程度和增量试探法计算出可能的变化尺度,然后采用多级正方形匹配法预测目标的运动趋势,将巴氏系数最大者的尺度作为Mean Shift核函数新的带宽。同时,对前景目标进行分块,根据子块的遮挡程度自适应改变子块权重并按一定准则融合有效子块的跟踪结果。实验结果表明,该算法具有很好的鲁棒性。展开更多
模块化多电平直流变压器(modular multilevel DC transformer, MMDCT)作为直流电网中的关键设备,承担了直流电压变换、功率传输和电气隔离的功能,而其稳定运行需要对众多级联的子模块采取电压均衡控制。针对现有方法无法简单可靠地实现...模块化多电平直流变压器(modular multilevel DC transformer, MMDCT)作为直流电网中的关键设备,承担了直流电压变换、功率传输和电气隔离的功能,而其稳定运行需要对众多级联的子模块采取电压均衡控制。针对现有方法无法简单可靠地实现宽电压增益范围和全功率运行工况时的子模块电容电压平衡问题,提出了一种桥臂内子模块电容均压的控制方法。该方法通过改变各子模块驱动脉冲占空比的方式实现类两电平调制,基于不同占空比的驱动脉冲向子模块电容进行电荷量不等的充电控制,并根据电容电压的排序来确定相应子模块驱动脉冲的占空比,进而实现子模块电压均衡。所提方法使得MMDCT能够运行在宽电压增益范围和全功率运行工况下,且具有无需实时检测桥臂电流、计算量少等优点。最后通过仿真和实验验证了理论分析的正确性和所提均压方法的可行性和有效性。展开更多
文摘This paper introduces the class of seasonal fractionally integrated autoregressive<span style="font-family:Verdana;"> moving average</span><span style="font-family:Verdana;">-</span><span style="font-family:Verdana;">generalized conditional heteroskedastisticty (SARFIMA-</span><span style="font-family:;" "=""> </span><span style="font-family:Verdana;">GARCH) models, with level shift type intervention that are capable of capturing simultaneously four key features of time series: seasonality, long range dependence, volatility and level shift. The main focus is on modeling seasonal level shift (SLS) in fractionally integrated and volatile processes. A natural extension of the seasonal level shift detection test of the mean for a realization of time series satisfying SLS-SARFIMA and SLS-GARCH models w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> derived. Test statistics that are useful to examine if seasonal level shift in a</span><span style="font-family:Verdana;">n</span><span style="font-family:Verdana;"> SARFIMA-GARCH model </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> statistically plausible were established. Estimation of SLS-SARFIMA and SLS-GARCH parameters w</span><span style="font-family:Verdana;">as</span><span style="font-family:Verdana;"> also considered.</span>
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10174024 and 10474025)
文摘We investigate the energy-level shift of a hydrogen atom in a two-dimensional optical microcavity, where there exists a Bose-Einstein condensation of photons. It is found that below the critical temperature Tc, the energy-level shift of the bound electron is dependent on temperature, and it is a monotonically increasing function of the absolute temperature T. Especially, at the absolute zero temperature, the energy-level shift entirely comes from the Lamb shift, and the atom can be treated approximately, that is, in vacuum.
文摘In this paper, we introduce the class of autoregressive fractionally integrated moving average-generalized autoregressive conditional heteroskedasticity?(ARFIMA-GARCH) models with level shift type intervention that are capable of capturing three key features of time series: long range dependence, volatility?and level shift. The main concern is on detection of mean and volatility level shift in a fractionally integrated time series with volatility. We will denote such a time series as level shift autoregressive fractionally integrated moving average (LS-ARFIMA) and level shift generalized autoregressive conditional heteroskedasticity (LS-GARCH). Test statistics that are useful to examine if mean and volatility level shifts are present in an autoregressive fractionally integrated moving average-generalized autoregressive conditional heteroskedasticity (ARFIMA-GARCH) model are derived. Quasi maximum likelihood estimation of the model is also considered.
基金financial support from the National Key R&D Program of China(2021YFB3500700)the National Natural Science Foundation of China(22473042,22003016,and 92145302).
文摘The use of metal oxides has been extensively documented in the literature and applied in a variety of contexts,including but not limited to energy storage,chemical sensors,and biomedical applications.One of the most significant applications of metal oxides is heterogeneous catalysis,which represents a pivotal technology in industrial production on a global scale.Catalysts serve as the primary enabling agents for chemical reactions,and among the plethora of catalysts,metal oxides including magnesium oxide(MgO),ceria(CeO_(2))and titania(TiO_(2)),have been identified to be particularly effective in catalyzing a variety of reactions[1].Theoretical calculations based on density functional theory(DFT)and a multitude of other quantum chemistry methods have proven invaluable in elucidating the mechanisms of metal-oxide-catalyzed reactions,thereby facilitating the design of high-performance catalysts[2].
文摘A novel level shift circuit featuring with high dV/dt noise immunity and improved negative V_S capacity is proposed in this paper.Compared with the conventional structure,the proposed circuit adopting two cross-coupled PMOS transistors realizes the selective filtering ability by exploiting the path which filters out the noise introduced by the dV/dt.In addition,a differential noise cancellation circuit is proposed to enhance the noise immunity further.Meanwhile,the negative V_S capacity is improved by unifying the detected reference voltage and the logic block＇s threshold voltage.A high voltage half bridge gate drive IC adopting the presented structure is experimentally realized by using a usual 600 V BCD process and achieves the stable operation up to 65 V/ns of the dV/dt characteristics.
文摘In this paper, we proposed a metric to measure the shift invariance of the three different contourlet transforms. And then, using the same structure texture image retrieval system which use subband coefficients energy, standard deviation and kurtosis features with Canberra distance, we gave a comparison of their texture description abilities. Experimental results show that contourlet-2.3 texture image retrieval system has almost retrieval rates with non-sub sampled contourlet system;the two systems have better retrieval results than the original contourlet retrieval system. On the other hand, for the relatively lower redundancy, we recommend using contourlet- 2.3 as texture description transform.
文摘In modern fiction translation, translators occasionally encounter multitudinous problems, which need to be solved by various translation tactics. The paper hereof aims to adopt John Catford's shifts theory to analyze the tactics used to solve the problems in fiction translation on syntactical level via translating Best Kept Secret.
文摘模块化多电平直流变压器(modular multilevel DC transformer, MMDCT)作为直流电网中的关键设备,承担了直流电压变换、功率传输和电气隔离的功能,而其稳定运行需要对众多级联的子模块采取电压均衡控制。针对现有方法无法简单可靠地实现宽电压增益范围和全功率运行工况时的子模块电容电压平衡问题,提出了一种桥臂内子模块电容均压的控制方法。该方法通过改变各子模块驱动脉冲占空比的方式实现类两电平调制,基于不同占空比的驱动脉冲向子模块电容进行电荷量不等的充电控制,并根据电容电压的排序来确定相应子模块驱动脉冲的占空比,进而实现子模块电压均衡。所提方法使得MMDCT能够运行在宽电压增益范围和全功率运行工况下,且具有无需实时检测桥臂电流、计算量少等优点。最后通过仿真和实验验证了理论分析的正确性和所提均压方法的可行性和有效性。
