电力系统中的电力电子设备所产生的谐波数量日益增加,谐波问题是一个备受关注的话题。本文通过引入压缩感知理论和平行因子模型,提出了一个用于谐波和间谐波的频率估计算法。先从信息发送终端中获取数据,然后使用欧拉公式将正弦信息转...电力系统中的电力电子设备所产生的谐波数量日益增加,谐波问题是一个备受关注的话题。本文通过引入压缩感知理论和平行因子模型,提出了一个用于谐波和间谐波的频率估计算法。先从信息发送终端中获取数据,然后使用欧拉公式将正弦信息转化为空域信息构造多时延输出并建立为平行因子模型,再对模型进行压缩后进行平行因子分析。最后将所得的数据经过贪婪算法重构,再进行频率值的估计。与传统的平行因子计算比较,该计算具有压缩过程,计算工作量相对较小,对数据存储容量需求也较少。所提计算的频谱估计性能与传统的平行因子分解算法(Parallelfactorization,PARAFAC)非常接近,而且也比采用旋转不变技术的信号参数估计算法(Estimating signal parameter via rotational invariance techniques,ESPRIT)更加精确。展开更多
In order to better understand the general tidal features in the venturi-shaped area between Zhenhai and Shenjiamen in the northern coastal region of Zhejiang Province in the East China Sea, the tidal data were obtaine...In order to better understand the general tidal features in the venturi-shaped area between Zhenhai and Shenjiamen in the northern coastal region of Zhejiang Province in the East China Sea, the tidal data were obtained from both the three permanent tide stations of Zhenhai, Dinghai and Shenjiamen, and four temporary tide stations of Mamu, Chuanshan, Guoju and Liuheng, along with the current speed being observed at Luotou Waterway. Results from harmonic analysis show that: (1) The area was dominated by shallow water tides with irregular semi-diurnal features, and the smallest tidal range occurred in the area near a crossing line between Zhenhai and Dinghai stations, indicating that a tidal node existed in the southern Hangzhou Bay; (2) Formulae, HS2/HM2 >0.4 and gM2-(gK1+gO1)=270° (where H and g are harmonic constants), could be used as judging criteria for high and low tidal level diurnal inequalities; (3) The duration difference between ebb and flood tides could be roughly assessed by the ratio of HM4 vs. HM2; and the larger the ratio is, the bigger the duration difference is. At the same time, the duration period could be assessed by 2gM2-gM4, the epoch difference between M2 and M4 tidal constituents. If 2gM2-gM4 <180°, then the ebb duration is longer than the flood duration; if 180°< 2gM2-gM4 <360°, the result is reversed; (4) Taking Dinghai station as a center point, the highest tidal levels and the average high tidal levels, as well as the average tidal ranges at all stations became higher and larger both southeastwards and northwestwards, while the lowest tidal levels and the average low tidal levels appeared to be lower both southeastwards and northwestwards; and (5) The tidal patterns were not all in line with the tidal current patterns. As a conclusion, the smallest tidal range occurred in the narrow part of the venturi-shaped area. Along the both sides of the area, the highest tidal level and tidal range became higher and larger, while the lowest tidal level became lower with the increase of the distance from the narrow throat area. This is somehow different from the theory that the tidal level increases gradually when it moves towards the top narrow area of a V-shaped bay or estuary.展开更多
Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this pheno...Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this phenomenon are introduced in this paper,and co-seismic response data of water temperature and water level are used to check the thermometer time system,confirming that this phenomenon is true. Using the harmonic analysis method,variations of time difference between water temperature and water level for the M2 wave are worked out,which indicates that this phenomenon exists during the whole observation. According to the variations of phase lags for water temperature and water level,and the survey of observation conditions, it is considered that the abnormal phenomenon may be related to inadequate passage of water caused by a well blockage at the depth where the water temperature probe was set.展开更多
We completely characterize commuting dual Toeplitz operators with bounded harmonic symbols on the harmonic Bergman space of the unit disk. We show that for harmonic ■ and ψ, S■Sψ= SψS■ on(L2h)⊥if and only if ■...We completely characterize commuting dual Toeplitz operators with bounded harmonic symbols on the harmonic Bergman space of the unit disk. We show that for harmonic ■ and ψ, S■Sψ= SψS■ on(L2h)⊥if and only if ■ and ψ satisfy one of the following conditions:(1) Both ■ and ψ are analytic on D.(2) Both ■ and ψ are anti-analytic on D.(3) There exist complex constants α and β, not both 0, such that ■ = αψ + β.Furthermore, we give the necessary and sufficient conditions for S■Sψ= S■ψ.展开更多
We study some basic properties of weak Orlicz spaces and their applications to harmonic analysis.We first discuss the absolute continuity of the quasi-norm and its normality,then prove the boundedness of several maxim...We study some basic properties of weak Orlicz spaces and their applications to harmonic analysis.We first discuss the absolute continuity of the quasi-norm and its normality,then prove the boundedness of several maximal operators.We also establish a kind of Marcinkiewicz-type interpolation theorem between weak Orlicz spaces.As applications,the weak type analogues of several classical inequalities in harmonic analysis is obtained.展开更多
文摘电力系统中的电力电子设备所产生的谐波数量日益增加,谐波问题是一个备受关注的话题。本文通过引入压缩感知理论和平行因子模型,提出了一个用于谐波和间谐波的频率估计算法。先从信息发送终端中获取数据,然后使用欧拉公式将正弦信息转化为空域信息构造多时延输出并建立为平行因子模型,再对模型进行压缩后进行平行因子分析。最后将所得的数据经过贪婪算法重构,再进行频率值的估计。与传统的平行因子计算比较,该计算具有压缩过程,计算工作量相对较小,对数据存储容量需求也较少。所提计算的频谱估计性能与传统的平行因子分解算法(Parallelfactorization,PARAFAC)非常接近,而且也比采用旋转不变技术的信号参数估计算法(Estimating signal parameter via rotational invariance techniques,ESPRIT)更加精确。
基金Supported by Study on the Temporal and Spatial Distributions of Temperature and Salinity in Xiangshan Bay and the Northern Zhejiang Coastal Waters in the East China Sea of the Education Department of Zhejiang Provincial Government of China (Project No. 20061134)Study on Environment Dynamics and Nutrient Circulation in Xiangshan Bay and its Surrounding Areas in the East China Sea of the Second Institute of Oceanography, State Oceanic Administration, China (Project No. SOED0605)
文摘In order to better understand the general tidal features in the venturi-shaped area between Zhenhai and Shenjiamen in the northern coastal region of Zhejiang Province in the East China Sea, the tidal data were obtained from both the three permanent tide stations of Zhenhai, Dinghai and Shenjiamen, and four temporary tide stations of Mamu, Chuanshan, Guoju and Liuheng, along with the current speed being observed at Luotou Waterway. Results from harmonic analysis show that: (1) The area was dominated by shallow water tides with irregular semi-diurnal features, and the smallest tidal range occurred in the area near a crossing line between Zhenhai and Dinghai stations, indicating that a tidal node existed in the southern Hangzhou Bay; (2) Formulae, HS2/HM2 >0.4 and gM2-(gK1+gO1)=270° (where H and g are harmonic constants), could be used as judging criteria for high and low tidal level diurnal inequalities; (3) The duration difference between ebb and flood tides could be roughly assessed by the ratio of HM4 vs. HM2; and the larger the ratio is, the bigger the duration difference is. At the same time, the duration period could be assessed by 2gM2-gM4, the epoch difference between M2 and M4 tidal constituents. If 2gM2-gM4 <180°, then the ebb duration is longer than the flood duration; if 180°< 2gM2-gM4 <360°, the result is reversed; (4) Taking Dinghai station as a center point, the highest tidal levels and the average high tidal levels, as well as the average tidal ranges at all stations became higher and larger both southeastwards and northwestwards, while the lowest tidal levels and the average low tidal levels appeared to be lower both southeastwards and northwestwards; and (5) The tidal patterns were not all in line with the tidal current patterns. As a conclusion, the smallest tidal range occurred in the narrow part of the venturi-shaped area. Along the both sides of the area, the highest tidal level and tidal range became higher and larger, while the lowest tidal level became lower with the increase of the distance from the narrow throat area. This is somehow different from the theory that the tidal level increases gradually when it moves towards the top narrow area of a V-shaped bay or estuary.
基金funded by the 12th "Five-year Plan" of National Science and Technology Sponsored Project,China(2012BAK19B02-04)
文摘Tidal phase of water temperature in Qixian well,Shanxi Province is ahead of water level,which is different from the normal tidal relationship between water temperature and water level. Observation curves of this phenomenon are introduced in this paper,and co-seismic response data of water temperature and water level are used to check the thermometer time system,confirming that this phenomenon is true. Using the harmonic analysis method,variations of time difference between water temperature and water level for the M2 wave are worked out,which indicates that this phenomenon exists during the whole observation. According to the variations of phase lags for water temperature and water level,and the survey of observation conditions, it is considered that the abnormal phenomenon may be related to inadequate passage of water caused by a well blockage at the depth where the water temperature probe was set.
基金supported by National Natural Science Foundation of China(Grant Nos.10971020 and 1127059)Research Fund for the Doctoral Program of Higher Education of China
文摘We completely characterize commuting dual Toeplitz operators with bounded harmonic symbols on the harmonic Bergman space of the unit disk. We show that for harmonic ■ and ψ, S■Sψ= SψS■ on(L2h)⊥if and only if ■ and ψ satisfy one of the following conditions:(1) Both ■ and ψ are analytic on D.(2) Both ■ and ψ are anti-analytic on D.(3) There exist complex constants α and β, not both 0, such that ■ = αψ + β.Furthermore, we give the necessary and sufficient conditions for S■Sψ= S■ψ.
基金supported by National Natural Science Foundation of China (Grant No.11071190)
文摘We study some basic properties of weak Orlicz spaces and their applications to harmonic analysis.We first discuss the absolute continuity of the quasi-norm and its normality,then prove the boundedness of several maximal operators.We also establish a kind of Marcinkiewicz-type interpolation theorem between weak Orlicz spaces.As applications,the weak type analogues of several classical inequalities in harmonic analysis is obtained.
