Table of Content

20 September 2008, Volume 44 Issue 5

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Four Dimensional Variational Data Assimilation of Multiple Types of Observations for a Severe Storm in Beijing Area

CHEN Min,ZHONG Jiqin,ZHENG Zuofang

2008, 44(5):  756-764. 

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Several real-data assimilation experiments were performed for a severe convective storm occurring in the Beijing area, by using the MM5 four-dimensional variational data assimilation (4DVAR) system with a full physics adjoin Several kinds of data were assimilated, including surface moisture observations with 3-hr interval, local 1-hr accumulated AWS precipitation and ground-based GPS precipitable water observations with 30-minute interval Assimilation results show that the MM5-4DVAR system is able to reproduce the observed rainfall in terms of precipitation pattern and amount It is found that the model's forecast performance for precipitation are greatly improved not only during the assimilating window, but after that, especially when compared with the 3-hr accumulated AWS precipitation observations From the analysis innovates of the wind, moisture and temperature, the optimal initial conditions generated from the 4DVAR data assimilation of multiple observations may generate much more convective available potential energy, which is favorable to initiate convection In addition, the significance of each type of data was tested The surface moisture did not have significant impact on predicting the amount and pattern of precipitation However, its assimilation was helpful to recover the vertical moisture Ground-based GPS PW data had the maximum positive impact for model's performance The assimilation of precipitation observations is important for improving precipitation forecasts, especially for that after the assimilating window

Climatology of Fog in Guizhou Province

LUO Xiping,YANG Jing,ZHOU Chengxia

2008, 44(5):  765-772. 

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The observed daily meteorological phenomena and visibility of 84 stations from 1961 to 2004 are used to study the special and temporal character of fog climatology in Guizhou Province Also daily ground and air temperature, relative humidity of 9 selected sample stations are also included The mean annual geographical distribution of fog frequency in Guizhou is randomly The average annual fog frequency is 299 days The stations with more than 60 mean annual fog day frequency scatter in the east, west and central area of Guizhou with relatively high altitude There are 3 stations whose annual fog frequencies exceed 100 days The highest fog frequency of Guizhou is 170 days in Dafang county of Bijie The seasonal and diurnal variations of fog occurrence are obviously Although fog may occur in each season, but most of fog occur in cold season (from October to February) and less from May to July On the diurnal time scale, fog events occur mainly on 0800 of local time The mean annual fog frequency show a decreasing trend with a rate of 006 day per year Further statistical study based on meteorological data show that the decrease of mean fog occurrence might be caused by several climate changed issues: a rising trend of the mean daily lowest temperature in winter, a decreasing trends in the difference between ground and surface air temperature,the annual mean difference between higest and lowest surface air temperature,and the annual mean surface relative humidity

Research on Multivariate Analysis for Symptom Diagnosis in Traditional Chinese Medicine

WANG Xi,SONG Jiannan,FANG Xiangzhong

2008, 44(5):  669-675. 

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Based on the data from the project “Study on the Proteomics about Phlegm and Blood Stasis Symptom in Hyperlipidemia and Atherosclerosis”, multivariate analysis are used to help find the most powerful protein groups for TCM symptom diagnosis Clustering methods on both variables and samples are used to analyze the 11 proteins, and two possibilities for the variable clustering results are given from the TCM perspective to supervise the sample clustering in different ways Moreover, hypothesis tests are introduced to support the classification independently Either the protein group {Haptoglobin (Precursor),α-trypsin inhibitor light chain, ALB protein3, Complement component C4} or the protein group {Fibrinogen gamma chain, α-trypsin inhibitor light chain, undetermined protein (ID1485)} is found to excellently separate not only the symptoms and the control group, but also the phlegm and the blood stasis symptoms Therefore, suggestions for better TCM symptom diagnosis are given out

Cauchy Problem for the “Bad” Boussinesq-Type Equation with Damping Term

LI Qingshan,LI Hong,SONG Changming,ZHANG Yiran

2008, 44(5):  676-682. 

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The Cauchy problem for the “bad” Boussinesq-type equation with damping term u_u-u_xx-2ku_xxt-αu_xxxx=β(u<>sup>n)_xx is studied Where k, α and β are real numbers, with k>0,α>0, and n≥2 is an integer It proves that for any T>0 the Cauchy problem admits a global smooth solution u∈C^∞((0,T］;H^∞(R))∩C(［0，T］;H1(R))∩C1(［0，T］;H-1(R)) under suitable assumptions on the initial data

Wave Propagation in Elastic Square Columns
ⅡTransient Response in Limited Square Column

WEI Jianping,SU Xianyue

2008, 44(5):  683-688. 

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This is a continue work in studying the wave propagation in elastic square columns Based on the previous work, the transient response of the limited column was studied After obtaining the analytic transient response acted by arbitrary external force, the warped surface in the terminal and the mechanical signs propagating processes in the channels formed by the Quasi-P, Quasi-SV and Quasi-SH waves were clearly displayed in the plotted figures Some regularities of the wave propagation were found from this closed system

Experimental Research on Parameters of Constitutive Model for a Cement Mortar

CHEN Jianlin,LI Xudong,LIU KaixinCollege of Engineering,Peking University,Beijing 100871； Corresponding Author,E-mail: kliu@pku.edu.cn

2008, 44(5):  689-694. 

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Based on the theoretical analysis on JHC model, a series of experiments for those parameters of JHC model are designed, and the parameters of a sort of cement mortar are acquired through experiments. A numerical simulation for the failure process of a cement mortar plate due to explosive loading is performed by using LS-DYNA software. The numerical simulate results are in agreement well with the experimental results, which indicates that mechanical parameters for JHC model measured by authors' experiments are effective and valid.

Quasi-Distribution-Based Similarity Analysis of Chromatographic ?Fingerprint of Herbal Medicine

AN Jinbing,XU Yuqiong,HE Dongqi,CAI Shaoqing

2008, 44(5):  695-699. 

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Focusing on the problem of high variability of peak area in chromatographic fingerprint of herbal medicine，a new approach on the similarity analysis based on the quasi-distribution function is proposed Each peak area of chromatographic fingerprint with high variability is transformed into comparative rankThen after a series of data transformations on original data，the quasi-distribution function is obtained and Kolmogorov test is used to evaluate the similarity of fingerprints of two classes of samplesIn the end，by comparison among the samples of Aristolochia contorta and Aristolochia debilis，this method with high robustness and sensibility proved to be reasonable

The Calculation of Coherence Bandwidth on Shortwave Channel

LI Yanli,ZHANG Yiwei,DUAN Xiaohui,JIAO Bingli

2008, 44(5):  700-704. 

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The authors explain a double layers and plane valley electron density profile The coherence bandwidth of shortwave channel is calculated by using the density profile and wave propagation features in ionosphere Finally, coherence bandwidths for different operating frequencies and ground distances are obtained Because the double layers and plane valley model can analyze more exactly the multipath components and their path losses, it can obtain coherence bandwidths more closely to the measured values than those of the single layer model

An Efficient Privacy Preserving Method in OLAP

TAO Youdong,TONG Yunhai,TAN Shaohua,TANG Shiwei,YANG Dongqing

2008, 44(5):  705-710. 

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An optimized privacy preservation method for OLAP data is presented First the method simulates the original result data of query using polynomial regression Then two efficient rules are adopted to optimize the simulated result Kullback-Leibler divergence is adopted to measure the information utility which is hard to evaluate Experimental results indicate that this method gets the satisfying efficiency on the balance of the privacy and the utility

High Efficient Analog Charge Delay Lines for 288×4 ROIC

LU Wengao,CHEN Zhongjian,ZHANG Yacong,JI Lijiu

2008, 44(5):  739-743. 

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A high efficient analog charge delay line (ACDL) is proposed These analog delay lines can be used to realize high performance CMOS readout integrated circuits (ROIC) with time delay integration (TDI) function A CMOS ROIC for 288×4 IRFPA were designed, manufactured, and tested The chip has 4 video outputs, whose pixel frequency is 4-5MHz (for 384×288 format, its frame frequency can achieve 160Hz) Test results show that this chip has high dynamic range (>78dB), high linearity (>995%), and high uniformity (968%)

A Fast Hierarchical Multi-Objective Mapping Approach for Mesh-Based Networks-on-Chip

LIN Hua,ZHANG Liang,TONG Dong,LI Xianfeng,CHENG Xu

2008, 44(5):  711-720. 

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The authors proposes a fast hierarchical multi-objective mapping approach (HMMap) for mesh-based NoC Based on partition and multi-objective heuristic techniques, HMMap automatically maps large number of IP cores onto NoC architecture and makes good tradeoffs between communication energy and latency Experimental results show that proposed approach achieves shorter execution time, lower energy and latency compared with others With the increasing of NoC size, the optimization effect of HMMap becomes more obvious

A Novel Derivative Reliability Tag Estimation for RFID

GUO Hongbo,ZHAO Yuping

2008, 44(5):  721-726. 

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It is especially important for slotted-ALOHA RFID to estimate tag number in order to allocate slot number optimally and maximize the efficiency The existing tag estimation methods are not accurate enough especially when tags overnumber slots What's more, their applicable ranges are quite limited A novel tag estimation method DRCTE(Derivative Reliabilities Combined Tag Estimation) is proposed Three primary estimations are obtained respectively from the rates of empty, occupy and collide slot number to the whole slot number, then their reliabilities are evaluated from the derivatives of the rates, and at last the three primary estimations are combined to get the final estimation result The proposed DRCTE algorithm not only utilizes the reliable information but also restrains unreliable information, so it is more accurate and its applicable range is larger

On the Maximum Average Degree and the Incidence Chromatic Number

WANG Shudong,YAN Lijun,LIU Xiangrong

2008, 44(5):  727-732. 

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An incidence coloring of graph G is a mapping from the incidence set I(G) to color set C such that any two neighborly incidences are assigned different colors The authors discussed incidence coloring of graph and proved graph G with mad(G)<3,Δ(G)=4 to admit a (6,2)-incidence coloring by the induction and the exchanging colors method from the aspect of configuration property

Optimize Cryptographic Symmetric Primitives Performance

LIU Yong,CHEN Yu,CHEN Zhong

2008, 44(5):  733-738. 

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How to optimize AES-128, SHA-256, SHA-512 and Whirlpool algorithms on Loongson-2E is discussed The corresponding optimize techniques are raised for the four algorithms, and the optimized results are analyzed The programs are, to the best knowledge, the fastest implementations on Loongson-2E This paper also proposed several new instructions for speedup symmetric primitives and a parallel hash function mode

Analysis of the Micro-Meteorologic Element During the Advection Fog Period in the South of Tianjin City

WU Bingui,ZHANG Hongsheng,ZHANG Changchun,WANG Zhaoyu,YU Lili,LIU Binxian,XIE Yiyang

2008, 44(5):  744-750. 

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The micro-meteorological elements of an advection fog, which occurred in Feb 2006, were analyzed by using data from the Tianjin Meteorological Boundary Layer Tower The results show that temperature inversion and higher humidity are due to the warm and moist south-west advection, which provides the necessary conditions for the formation and maintaining of the advection fog The advection fog comes under the weak unstable condition There are double-inverse temperatures during the fog period with wind speed decreasing and wind direction shearing The fog dissipates from higher to lower layers with dry and cold air coming from the northwest associated with a cold front The long-lasting fog at lower layers is due to the subsidence inverse of cold air There is a close correlation between the characteristics of temperature profile and thickness of fog

Application of Optical Flow Method to Nowcasting Convective Weather

HAN Lei,WANG Hongqing,LIN Yinjing

2008, 44(5):  751-755. 

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An optical flow method instead of the cross correlation method is proposed for convective precipitation system Compared with the simple algorithm of the cross correlation method, the optical flow method utilizes partial differential equations to compute the optical flow field, and uses strict constraints to get a smooth optical flow field The results show that the optical flow is superior to the cross correlation method for convective precipitation systems which evolve fast

Numerical Study of the Genesis and Development of TyphoonWUKONG (2000) over South China Sea

YI Bingqi,Alexis Kai-Hon,LAULIANG Aimin,ZHANG Qinghong

2008, 44(5):  773-780. 

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The Fifth generation NCAR/PSU mesoscale nonhydrostatic model(MM5) was used to simulate the process that a tropical disturbance developed into a strong typhoon WUKONG over the South China Sea in September 2000 The MM5 model could forecast the maximum wind and intensity of the typhoon with considerable accuracy The natural developing characteristics of South China Sea Typhoon which involved step-by-step deepening and drastic strengthening were also well simulated Based on some diagnostic variable analysis, the potential factors on typhoon structure as well as the genesis of typhoon eye were briefly analyzed Sensitivity experiments on sea surface temperature (SST) effect indicate that the SST is of vital importance to the genesis and development of typhoon over South China Sea If SST is degraded by 1 degree, the simulated typhoon would have a decrease of 10m/s on maximum wind and a nearly seven-hour delay to reach typhoon level intensity (surpass 328m/s) If SST is degraded by 2 degree (with SST still being between 26 and 27 degree), the initial tropical disturbance could hardly develop into typhoon

Design and Development of 3D Urban Geological Data Management and Service System

QU Honggang,PAN Mao,LV Xiaojian,LIU Xueqing,ZHANG Yongbo,YU Chunlin

2008, 44(5):  781-786. 

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The history and current status of urban informationization are firstly analyzed The design for 3DUGS (3D geological data management and service system), including system target, architecture and main functions, data analysis and processing procedure, key tecknologies, is introduced Finally, the application of this design in the development of Beijing 3DUGS is presented

Adoption of COMPOSITE Pattern and XML to Implement UniformDescription and Storage for Variogram

YAO Lingqing,PAN Mao,WANG Zhangang,QU Honggang

2008, 44(5):  787-792. 

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A memory prototype of variation function based on COMPOSITE design pattern is proposed, through which a uniform visiting interface is implemented and greatly improves the maintainability and expansibility of indispensable code in whole project Furthermore serialization of variation function and dynamically loading from storage is implemented with XML Serialization of variation function with XML not only can store away model's information, but can reveal the inner structure of model, and provide basis of evaluation, analysis, contrast and selection of models, as well as repetition use of model under analogical geological environment

Joint Layered and Multiple Description Image Coding Based on Directional Wavelet Transform

LI Xin,ZHANG Feizhou

2008, 44(5):  793-798. 

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With the goal of achieving both robustness to unreliable channels and adaptivity to client bandwidth heterogeneity and network congestion, the authors explore constructions for layered multiple description codes, where base layer descriptions can be transmitted to low bandwidth clients, while both base and enhancement layer descriptions can be transmitted to high bandwidth clients The multiple description coding is used to resolve the problem of transmission over unreliable channel Directional wavelet transform is selected to remove redundancy among neighboring pixels in order to high coding efficiency Through comparisons with other traditional multiple description the new architecture can obtain better quality of image in unreliable network channels

The Origin of Permian and Triassic Dolostones in Northeastern Sichuan Province，China

ZHANG Tingting,LIU Bo,QIN Shan

2008, 44(5):  799-809. 

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According to the lithology and geochemistry analyses, the Permian and Triassic dolostones in Northeastern Sichuan Province can be classified into three types: reef dolostone, grain dolostone and gypsum-bearing muddy dolomicrite The reef dolostone is formed in mixed water which is mainly controlled by frequent change of the sea level Grain dolostone is formed in the deep burial dolomitic environment by mixing-water dolomitization Penecontemporaneous or seepage-reflux dolomitization is the original mechanism for gypsum-bearing muddy dolomicrite

Object Tracking by Using SVM and Trust-Region Method

JIA Jingping,ZHANG Feizhou,CHAI Yanmei

2008, 44(5):  810-814. 

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An SVM (support vector machine) classifier is used to classify the pixels and generate a reliable target probability distribution image The outstanding trust region numeric optimization algorithm is utilized to locate the target as well as determine its size The SVM classifier's low error rate of classification offers a better base for the trust region algorithm Comparison with existing method and present tracking examples show that the proposed method is better in both target detection and precision improvement

Thermal Environment Effect of Land Use in Urban Area： A Case Study in Ningbo Urban Area

JIA Jingping,ZHANG Feizhou,CHAI Yanmei

2008, 44(5):  810-814. 

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High spatial resolution remote sensing data from both QUICKBIRD and Landsat ETM+ is utilized to assess urban area land use and associated thermal effects by taking Ningbo urban area as a case study To depict the spatial characteristics of urban thermal environment, the profile analysis is used Total heat effect index and weighted heat effect index are utilized to definitude the positive and negative thermal effects of each land use type quantitatively Analysis results suggest that urban heat island effect exists in Ningbo urban area However, there is obvious difference among surface radiant temperature of each constructed land types Industry land, old resident land, traffic land and unused land have positive effects on thermal environment, and the positive thermal effect of industry land is the most remarkable Water body, plantation, new resident land and urban green land have negative effects on thermal environment, and the negative thermal effect of water body is the most remarkable Areas with high surface radiant temperature in Ningbo urban area include three types: high energy consuming areas, centre of human and materials, and high radiance areas

Operation Service Quality Assessment Analysis Oriented Public Traffic Vehicles Optimal Scheduling

ZHANG Feizhou,CHEN Jia,YANG Bogang

2008, 44(5):  822-826. 

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It is reasonable and efficient to introduce artificial intelligence methods into public traffic vehicles (PTV) operations and management The public traffic managers establish accordant operation dispatching solution using quick and convenient intelligent dispatching algorithm on the basis of actual operation condition Therefore the efficiency operation management of PVT can availably be enhanced Using the intelligent features of genetic algorithm(GA), some operation management problems of PTV in Beijing were researched The simulation test shows that the intellectualized PTV scheduling is realized by the intelligent scheduling method based on GA Passenger waiting time model is deduced by queuing theory on this basis Finally the operation service quality is analyzed for the scheduling solutions The simulation results and the assessment analysis show that the GA is effective and viable for PTV scheduling

Comparative Analysis among Different Methods of Leaf Area Index Inversion

LIU Xiaochen,FAN Wenjie,TIAN Qingjiu,XU Xiru

2008, 44(5):  827-834. 

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Based on the simulated data produced by PROSAIL model and field test data, the authors respectively analyzed many kinds of factors which affect some representative inversion methods, such as VI, second derivative, model inversion and the directional second derivative The factors taken into account include background, directional variation of canopy reflectance and random errors and so on The results demonstrate that under various conditions, there are huge differences araong the inversion results resulted from these methods Vegetation index NDVI has the lowest accuracy, could not avoid those influences The accuracy of model inversion is better than that of VI method, but is still influenced by the variety of backgrounds The second derivative can partly remove the influence of backgrounds, but it is also limited by the anisotropy of canopy reflectance By comparison, the directional second derivative can improve inversion accuracy through removing the influences from the soil background and directional variation of canopy reflectance simultaneously As second derivative is sensitive to noise, the elimination of noise is crucial to the inversion result