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Energy dispersion of complex non-isolated vortices

Chinese science Bulletin 2011年第25期56卷 2713-2717页

作者： luo zhexian 1,2.1 {2. laboratory of Meteorological disaster of ministry of education, nanjing university of information science and technology, nanjing 2.0044. china 2.Wuxi Research Center of Environmental science and technology, Wuxi 2.4031, china key laboratory of Meteorological {2. of ministry of education Nanjing University of Information Science and Technology Wuxi Research Center of Environmental science and technology

Energy dispersion is a fundamental scientific problem in the study of natural disasters such as typhoons, heavy rain and earthquakes. The problem has been addressed by both multi-discipline research and forecast studies. The dynamics of isolated circular vortex energy dispersion have been solved. However, the disastrous results of typhoons and heavy rain often occur due to non-isolated circular vortices, the dynamics of which are explored in this paper. The energy dispersion characteristics of non-isolated vortices with complex structural patterns are examined using a linearized nondivergent barotropical vorticity equation model. In the initial field, a tropical cyclone (TC) vortex and a meso-scale vortex coexist, forming a complex structural pattern. An analytic solution based on a Fourier transform and simulations using a two-dimensional model show the following. (1) A wave train of TC-G-D may be created by the energy dispersion where the line connecting the three member centers of the wave train is parallel to the x axis in the case of an initial TC vortex without a meso-scale vortex. (2. A wave train of TC-G-D may also be created by energy dispersion. However, the line connecting the three member centers of the wave train would no longer be parallel to the x axis. Instead, they would form a triangle in the presence of the initial TC vortex with the meso-scale vortex. (3) There is a nonlinear relationship between the initial intensity of the meso-scale vortex and the base angle of the triangle. These results have the potential to be applied in the field of typhoon forecasting.

关键词：能量色散非隔离式旋涡非线性关系中尺度涡台风预报结构模式傅立叶变换

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On the interannual variation in spring atmospheric inter-hemispheric oscillation linked to synchronous climate in china

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Progress in Natural science:Materials International 2009年第9期19卷 1125-1131页

作者： Chuhan Lu, Zhaoyong Guan * key laboratory of Meteorological {2. of ministry of education and College of Atmospheric sciences, nanjing university of information science and technology, nanjing 2.0044. china [a]key laboratory of Meteorological {2. of ministry of education and College of Atmospheric sciences Nanjing University of Information Science and Technology Nanjing 210044 China

Based on NCEP/NCAR monthly mean reanalysis data and surface observations of Chinese stations, inter-hemispheric oscillations (IHO) of spring atmospheric mass on an interannual basis in conjunction with the linkage to the synchronous climate over china are studied. Results suggest that the spring IHO exhibits a significant seesaw pattern for air mass at bi-hemispheric mid-high latitudes, with a consistent vertical circulation structure. The EOF decomposition of zonally mean surface pressures without signals of Arctic Oscillation (AO) and Antarctic Oscillation (AAO) indicates that the EOF1 IHO feature is remarkable, with the corresponding time coeficients correlated with the spring IHO index (IIHO) at 0.93; the spring IHO bears a close relation to the synchronous climate in china, showing the surface pressure, temperature and relative humidity over the country to be in good correlation with IIHO; the spring duststorms in Qinghai, Gansu, Shaanxi and Inner Mongolia have bearing on IHO. Positive-phase IIHO promotes the strengthening of the Siberian high, during which zonal winds between 60°E and 150°W show a longitudinal teleconnection structure extending from the Arctic to Antarctica, leading to positive westerly wind anomalies over Asia, affecting the spring climate of china.

关键词： Air mass Inter-hemispheric oscillation (IHO) Spring climate china

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Interhemispheric atmospheric mass oscillation and its relation to interannual variations of the Asian monsoon in boreal summer

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science china Earth sciences 2010年第9期53卷 1343-1350页

作者： LU ChuHan, GUAN ZhaoYong & CAI JiaXi key laboratory of Meteorological {2. of ministry of education and College of Atmospheric sciences, nanjing university of information science & technology, nanjing 2.0044. china 1. key laboratory of Meteorological {2. of ministry of education and College of Atmospheric sciences Nanjing University of Information Science & Technology Nanjing 210044 China

Using NCEP/NCAR reanalysis and precipitation records of Chinese stations, we have investigated the relationship of interhemispheric oscillation of air mass (IHO) with global lower-level circulation and monsoon anomalies in boreal summer. Our results show that the summer IHO explains a greater portion of variance in the abnormal distribution of atmospheric mass over 30°S-60°N as well as the Antarctic. The IHO strongly correlates to the variations of sea level pressure (SLP) in these regions. It is shown that IHO has some influences on both atmospheric mass transports and water vapor fluxes over 30°S-60°N in association with three anomalous cyclonic circulations over land areas of the eastern hemisphere, which is in close relation to the changes in summer monsoon intensity in eastern Asia and western Africa. Composites of summer rainfall anomalies in china for high and low IHO-index years indicate that the eastern Asian summer monsoon is more intense, with positive precipitation anomaly centers in northern and northeastern parts of china, as opposed to the negative center over the mid-lower reaches of the Yangtze River (MLRYR) in stronger IHO years. In weak IHO years, a feeble summer monsoon appears in eastern Asia, leading to positive center of precipitation anomalies displaced into the MLRYR. Furthermore, a teleconnection in wind fields between the western African and eastern Asian monsoon regions was observed in the middle and higher troposphere in the scenario of IHO. The anomalous cyclonic (anticyclonic) circulations along the path of this Africa-East Asia teleconnection were found to be just over the diabatic heating (cooling) centers, suggesting that diabatic forcings are responsible for the formation of this Africa-East Asia teleconnection.

关键词： interhemispheric oscillation Asian monsoon precipitation china boreal summer

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Sufficient and necessary conditions for Lyapunov stability of Lorenz system and their application

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science china({2. sciences) 2010年第8期53卷 1574-1583页

作者： luo Qi 1 , LIAO XiaoXin 2.& ZENG ZhiGang 2.1 College of {2. and Control, nanjing university of information science and technology, nanjing 2.0044. china 2.Department of Control science and Engineering, Huazhong university of science and technology, Image Processing and Intelligent Control key laboratory of education {12. of china, Wuhan 430074, china 1. College of information and Control Nanjing University of Information Science and Technology Nanjing 210044 China2. Department of Control Science and Engineering Huazhong University of Science and Technology Image Processing and Intelligent Control Key Laboratory of Education Ministry of China Wuhan 430074 China

The sufficient and necessary conditions for Lyapunov stability of the zero equilibrium point of Lorenz system are discussed, and some brief criteria are presented for globally exponential stability, globally asymptotical stability and instability. Furthermore, the behavior of the non-zero equilibrium point of Lorenz system is also investigated, and several sufficient and necessary conditions are provided for locally exponential stability and instability. The established theorems in this paper develop and extend the existing achievements on Lyapunov stability of Lorenz system. In conclusion, by applying the obtained results, some less conservative feedback-control laws are derived to guarantee the globally exponential stability of the chaos control of Chen system, Lu¨ system, Yang-Chen system and Yu-Xia Li system.

关键词： Lorenz system Lyapunov stability sufficient and necessary condition bifurcation values globally exponential synchronization

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Numerical simulation of Meiyu front and the diagnosis of moist vorticity vector

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Progress in Natural science:Materials International 2007年第11期17卷 1341-1347页

作者： Ping Fan1,2.and luo zhexian{2.. Institute of Atmospheric Physics, Chinese Academy of sciences, Beijing 10002., china 2. nanjing university of information sciences & technology, nanjing 2.0044. china) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China nanjing university of {2. sciences & technology Nanjing 210044 China

Moist vorticity vector is introduced to study the development and evolution of mesoscale convective vortex (MCV) in the Meiyu front precipitation with the Advanced Regional Predication System (ARPS). In this study, the heavy rainfall is simulated to investigate the genesis, development and dissipation of middle scale convective vortex, which occurred from 0000 UTC 3 July to 12.0 UTC 5 July over the Jianghuai River valley. Moist vorticity vector (MVV) has zonal, radial and vertical components in its 3D spatial distribution. The simulation shows that the vertical component of moist vorticity vector well demonstrates the spatial distribution characteristics of middle scale convective vortex, especially in the process of Meiyu front precipitation. Diagnosis upon zonal, radial averaged and mass-integrated quantities of MVV shows that its vertical component and the surface precipitating ratio are in phase with a correlation coefficient of 0.68, indicating that the vertical component of MVV is closely associated with the Meiyu front precipitation. In addition, the tendency of the vertical component of MVV is mainly determined by the interaction between the vorticity and the zonal and radial gradient of condensational or depositional heating.

关键词： moist vorticity vector mesoscale convective vortex Meiyu front precipitation

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Climatological Characteristics of Frontogenesis and Related Circulations over East china in June and July

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Acta meteorologica Sinica 2013年第2期27卷 144-169页

作者：侯俊管兆勇 key laboratory of Meteorological {2. of ministry of education Nanjing University of Information Science & Technology Jiangsu Meteorological Observatory

Based on daily precipitation data from 2.2.stations in East china and NCEP/NCAR daily global final analysis data in June and July from 2.00 to 2.10, the climatological characteristics of frontogenesis and related circulations have been analyzed. The results demonstrate that frontogenesis function distributes non- uniformly in East china. The different terms of the kinematic frontogenesis show different intensities and distributions of frontogenesis. The strongest frontogenesis integrated from different kinematic frontogenesis terms is observed in the Jianghuai area. Frontogenesis events are separated into four types as per the different shear and convergence types of horizontal wind along the strong frontogenesis band at 850 hPa. The four types include the warm shear type, cold shear type （with two subtypes）, west wind convergence type, and east wind convergence type. The events in different frontogenesis types occur with different frequencies over the past decade. The warm shear type occurs most frequently. Different types of frontogenesis have distinctive horizontal and vertical structures. Strong frontogenesis is featured with 340-K contour of 0se parallel to the frontal zone in the vertical. Varied large-scale circulation patterns manifested in shifted location and strength of cyclone or anticyclone, wind convergence, as well as vertical circulation structure are associated with different types of frontogenesis. Moreover, a strong positive correlation between frontogenesis and precipitation is found, i.e., the stronger the frontogenesis, the more precipitation there is. Daily precipitation related to the warm shear type frontogenesis is the largest, and often occurs inside the frontal zone with the same orientation with the strong frontogenesis belt. The second largest daily precipitation occurs with the cold shear type frontogenesis, and related rainfall is usually observed to the south of the frontal zone, with the rain belt extending northeastward. Precipitat

关键词： frontogenesis circulation pattern precipitation East china boreal summer

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Characteristic analysis of unsteady viscous flow around a cavitating propeller

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science china(Technological sciences) 2010年第7期53卷 1983-1992页

作者： ZHU ZhiFeng1, 2. FANG ShiLang1 & WANG XiaoYan1 1 key laboratory of Underwater Acoustic Signal Processing of {2. of education, Southeast university, nanjing 2.0096, china 2.School of Electrical Engineering and information, Anhui university of technology, Maanshan 2.3002. china 1. key laboratory of Underwater Acoustic Signal Processing of {2. of education Southeast University Nanjing 210096 China2. School of Electrical Engineering and Information Anhui University of Technology Maanshan 243002 China

Based on viscous multiphase flow theory, this paper presents some recent validation results with a hybrid grid and sliding mesh solving Unsteady Navier-Stokes (N-S) and Bubble Dynamics equations as applied to prediction of pressure, velocity and vapor volume fraction in the wake in an uniform inflow. Comparable to experimental results, numerical predictions of sheet cavitation, tip vortex cavitation and hub vortex cavitation are in agreement with the corresponding experimental data, the same as numerical predictions of pressure in wake. Tip vortex cavitation is the most important to generate the pressure fluctuation within the near wake. The characteristics such as blade and shaft rate frequency of propeller pressure in wake coincide with its geometric model and parameters. With increasing distance from propeller disk, the pressure signals at blade frequency de-crease. The process of attenuation becomes fast with the decreased advance coefficient and cavitation number.

关键词： cavitating flow RANS propeller sliding mesh multiphase flow

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Heuristic for no-wait flow shops with makespan minimization based on total idle-time increments

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science in china(Series F) 2008年第7期51卷 896-909页

作者： LI XiaoPing1,2.& WU Cheng3 1 School of Computer science & Engineering, Southeast university, {2. 2.0096, china 2.key laboratory of Computer Network and information Integration (Southeast university), ministry of education, {2. 2.0096, china 3 Department of Automation, Tsinghua university, Beijing 100084, china 1. School of Computer science & Engineering Southeast University Nanjing 210096 China 2. key laboratory of Computer Network and {2. Integration (Southeast university) Ministry of Education Nanjing 210096 China 3. Department of Automation Tsinghua University Beijing 100084 China

No-wait flow shops with makespan minimization are classified as NP-hard. In this paper, the optimization objective is equivalently transformed to total idle-time minimization. The independence relationship between tasks is analyzed, and objective increment properties are established for the fundamental operators of the heuristics. The quality of the new schedules generated during a heuristic is judged only by objective increments and not by the traditional method, which computes and compares the objective of a whole schedule. Based on objective increments, the time complexity of the heuristic can be decreased by one order. A seed phase is presented to generate an initial solution according to the transformed objective. Construction and improvement phases are introduced by experimental analysis. The FCH （fast composite heuristic） is proposed and compared with the most effective algorithms currently available for the considered problem. Experimental results show that the effectiveness of the FCH is similar to that of the best methods but requires far less computation time. The FCH can also be efficient in real time scheduling and rescheduling for no-wait flow shops.

关键词： no-wait flow shops heuristic makespan Tabu search

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A generalized mean shift tracking algorithm

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science china({2. sciences) 2011年第11期54卷 2373-2385页

作者： CHEN JianJun 1,4,ZHANG SuoFei 1,AN GuoCheng 2.& WU ZhenYang 1,31 School of information science and Engineering,Southeast {2.,nanjing 2.0096,china 2.Intelligence Engineering Lab,Institute of Software Chinese Academy of sciences,Beijing 100190,china 3 key laboratory of Underwater Acoustic Signal Processing of ministry of education,Southeast {2.,nanjing 2.0096,china 4 nanjing Research Institute of Electronic technology,nanjing 2.0013,china 1. School of information science and Engineering Southeast University Nanjing 210096 China4. Nanjing Research Institute of Electronic Technology Nanjing 210013 China2. Intelligence Engineering Lab Institute of Software Chinese Academy of Sciences Beijing 100190 China3. Key Laboratory of Underwater Acoustic Signal Processing of Ministry of Education Southeast University Nanjing 210096 China

CAMSHIFT algorithm and Comaniciu/Meer algorithm are two fundamental frameworks of mean shift procedure for video target *** paper generalizes the two well-known mean shift tracking algorithms,originally due to Bradski and Comaniciu/Meer.A new general similarity function which defines the distance between the target model and target candidate is employed to calculate the pixel weights and the target *** target size is iteratively estimated and updated based on the zeroth order moment of the pixel *** we prove that both the CAMSHIFT algorithm and the Comaniciu/Meer algorithm can be included in the generalized mean shift tracking *** tracking performances of three mean shift algorithms in the unified framework are shown and compared in the experimental results.

关键词： mean shift CAMSHIFT video target tracking similarity measure

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Research on heart sound identification technology

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science china({2. sciences) 2012年第2期55卷 281-292页

作者： CHENG XieFeng1,3,MA Yong2.LIU Chen1,ZHANG XueJun1 & GUO YuFeng11School of Electronic science and Engineering,nanjing {2. of Posts and Telecommunications,nanjing 2.0003,china 2.chool of Computer science and technology,nanjing {2. of science and technology,nanjing 2.0094,china 3key Lab of Broudbard Wireless Communication and Sensor Network technology(nanjing {2. of Posts and Telecommunications),ministry of education,nanjing 2.0094,china 1. School of Electronic science and Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China3. Ministry of Education Key Lab of Broudbard Wireless Communication and Sensor Network Technology (Nanjing University of Posts and Telecommunications) Nanjing 210094 China2. School of Computer Science and Technology Nanjing University of Science and Technology Nanjing 210094 China

In this article,both the basic principles and the experimental methods of identity recognition technology based on heart sounds are ***,the characteristics of heart sounds and the feasibility of heart sounds as a biometric were analyzed.A synthetic model of heart sounds was then developed based on a family of wavelets;Finally,the characteristic parameters of heart sounds were extracted by using the heart sounds linear band frequency cepstra(HS-LBFC)with a specified configuration,and the similarity distance was adopted for heart sound *** highlight the difference in two heart sound signals between the time and frequency domains,a construction method of the heart sound wavelet,a calculation method of the parameters of a synthetic model,selection of the characteristic parameters of heart sounds and the corresponding data processing technology were *** experimental results showed that the proposed method exhibited excellent performance and practicability.

关键词： biometric wavelet family of heart sounds synthetic model of heart sounds heart sounds linear band frequency cepstra(HS-LBFC)

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