时序信息提取特点的实验研究

时距区分性理论认为提取时序信息是在包含一定项目的检索系中检索抽样的过程,通道因素应当对正确率和速度都产生影响.本文分别以英文字母和汉字为材料,对时序信息的提取特点作了两个实验研究.结果表明,只有材料的呈现顺序对时序信息提取的正确率和速度都有影响,通道因素只影响提取的正确率,而速度则未受其影响。显然,用时距区分性理论来说明时序信息提取特点是缺乏足够证据的.本文提出,对时序信息提取机制尚值得进一步研究.

所有权保留的法律性质及其数理分析

所有权保留买卖是一个需要一定时间并处于不断变化之中的过程,因此对于它的法律性质等问题的研究要以对这个过程的考察为基础,而不能忽略这个过程。文章引入了模糊逻辑的思维工具,对所有权保留买卖的过程进行了具体、量化的考察,用模糊数学的函数模型将这一过程作了清晰的展示。并在时间区分所有权理论的基础上,提出了更富操作性的方法。

Synthesis Scheme for Low Power Designs Under Timing Constraints

To minimize the power consumption with resources operating at multiple voltages a time-constrained algorithm is presented.The input to the scheme is an unscheduled data flow graph (DFG),and timing or resource constraints.Partitioning is considered with scheduling in the proposed algorithm as multiple voltage design can lead to an increase in interconnection complexity at layout level.That is,in the proposed algorithm power consumption is first reduced by the scheduling step,and then the partitioning step takes over to decrease the interconnection complexity.The time-constrained algorithm has time complexity of O(n 2),where n is the number of nodes in the DFG.Experiments with a number of DSP benchmarks show that the proposed algorithm achieves the power reduction under timing constraints by an average of 46 5%.

飞行的分类

(一)按照飞行任务的性质区分:有运输飞行,专业飞行,急救飞行,训练飞行,科学试验飞行,公务飞行,专机飞行,包机飞行等。 (二)按照飞行区域区分:航线飞行,航站区域内飞行,作业地区飞行。 (三)按照昼夜时间区分:昼间飞行(从日出到日落之间),夜间飞行(从天黑到天亮之间)。

A NEW SINGULARITY EXTRACTION TECHNIQUE FOR TDEFIE

A new singularity extraction technique is presented to calculate accurately the singular integrals in Time Domain Electric Field Integral Equation (TDEFIE).In singularity extraction pro- cedure,through the aid of the first order Taylor series of time base function including time-retardation,the singularity of the integrand can be removed.The surface current density and backscattered far-field response of a conducting cube illuminated by a Gaussian plane wave is com- puted using the presented technique.Comparisons are made with the results obtained by the Inverse Discrete Fourier Transform (IDFT) of the frequency domain and the results obtained by using Ve- chinski's time averaging technique,which demonstrate that the presented method with this new time domain singularity extraction technique to solve TDEFIE is very accurate and stable.

Characteristics of the May 12,2008 Wenchuan M_S8.0 Earthquake Sequence and Discussion on Relevant Problems

The aftershock activity of the May 12, 2008 Wenchuan Ms8.0 Earthquake Sequence shows an obvious segmented feature. Most of the large aftershocks were distributed in the north and south parts of the aftershock zone. Thrusting was dominant with a small amount of strike-slip component in the south part. The aftershock activity decayed gradually, presenting the sequence features of a mainshock-aftershock pattern. The north part was the ending area of the malnshock fracture where strike-slipping was dominant, showing an obvious swarm feature. Therefore it became the major area for large aftershocks. The modulation of the earth tide on aftershock activity is remarkable; most large aftershocks occur during the period of flood and neap tide. The time period around 16：00 was the dominant occurring time for large aftershocks. The p-value, a parameter of modified Omori formula, increases gradually with time, and reaches about 1 at the end. Based on previous study, the sequence patterns, magnitude of maximum aftershock, as well as the duration of aftershock activity has been discussed. The primary results also show that the magnitude difference between the maiushock and the maximum aftershock is proportional to the rupture size of the maiushock for huge earthquakes of about Ms8.0. This means that when the magnitudes of the earthquakes are nearly the same, large rupture size corresponds to sufficient energy release.

Analysis of Abnormal Characteristics of Regional Crustal Deformation before the Menyuan MS6.4 Earthquake by GPS Continuous Data

In order to study the characteristics of crustal deformation around the epicenter before the 2016 M_S6. 4 Menyuan earthquake,the GPS continuous stations of the period from 2010 to 2016 were selected according to the observation data of the tectonic environment monitoring network in Chinese Mainland. The deformation characteristics of the crust before the earthquake were discussed through inter-station baseline time series analysis and the strain time series analysis in the epicentral region. The results show that a trend turn of the baseline movement state around the epicenter region occurred after 2014,and the movement after 2014 reflects an obvious decreasing trend of compressional deformation.During this period,the stress field energy was in a certain accumulation state. Since the beginning of 2014,the EW-component linear strain and surface strain rate weakened gradually before the earthquake. It shows that there was an obvious deformation deficit at the epicentral area in the past two years,which indicates that the region accumulated a high degree of strain energy before the earthquake. Therefore,there was a significant background change in the area before the earthquake. The results of the study can provide basic research data for understanding the seismogenic process and mechanism of this earthquake.

Snowline and Snow Cover Monitoring at High Spatial Resolution in a Mountainous River Basin Based on a Timelapse Camera at a Daily Scale

Snowline change and snow cover distribution patterns are still poorly understood in steep alpine basins of the Qilian Mountainous region because fast changes in snow cover cannot be observed by current sensing methods due to their short time scale. To address this issue of daily snowline and snow cover observations, a ground- based EOS 7D camera and four infrared digital hunting video cameras （LTL5210A） were installed around the Hulugou river basin （HRB） in the Qilian Mountains along northeastern margin of the Tibetan Plateau （38°15′54″N, 99°52′53″E） in September 2011. Pictures taken with the EOS 7D camera were georeferenced and the data from four LIL521oA cameras and snow depth sensors were used to assist snow cover estimation. The results showed that the time-lapse photography can be very useful and precise for monitoring snowline and snow cover in mountainous regions. The snowline and snow cover evolution at this basin can be precisely captured at daily scale. In HRB snow cover is mainly established after October, and the maximum snow cover appeared during February and March. The consistent rise of the snowline and decrease in snow cover appeared after middle part of March. This melt process is strongly associated with air temperature increase.

Automatic detection of oceanic mesoscale eddies in the South China Sea

This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to obtain an eddy dataset from 21 years of satellite altimeter data. Analysis revealed that the number of anticyclonic eddies was nearly equal to cyclonic eddies; in the SCS,cyclonic eddies are generally stronger than anticyclonic eddies and anticyclonic eddies are larger and longer-lived than cyclonic eddies. Anticyclonic eddies tend to survive longer in the spring and summer,while cyclonic eddies have longer lifetimes in the autumn and winter. The characteristics and seasonal variations of eddies in the SCS are strongly related to variations in general ocean circulation,in the homogeneity of surface wind stress,and in the unevenness of bottom topography in the SCS. The spatial and temporal variation of mesoscale eddies in the SCS could,therefore,be an important index for understanding local hydrodynamics and regional climate change.

AN IMPROVED GN ALGORITHM OF NETWORK COMMUNITY DETECTION METHOD

.GN algorithm has high classification accuracy on community detection, but its time complexity is too high. In large scale network, the algorithm is lack of practical values. This paper puts forward an improved GN algorithm. The algorithm firstly get the network center nodes set, then use the shortest paths between center nodes and other nodes to calculate the edge betweenness, and then use incremental module degree as the algorithm terminates standard. Experiments show that, the new algorithm not only ensures accuracy of network community division, but also greatly reduced the time complexity, and improves the efficiency of community division.

Correlation Analysis of Gridding of Earthquakes in Datong and Its Surrounding Areas and Implication for Earthquake Prediction

On the basis of the earthquake （gL I〉3.0） catalog in North China from 1970 to 2009, the pattern of temporal and spatial distribution of medium-small earthquakes in Datong and its surrounding areas is studied by correlation analysis with a focus on its anomaly before moderate and strong earthquakes. With different spatial scales, temporal scales and time steps, the spatial distribution of earthquakes is converted to a sequence, then the correlation coefficients between the spatial distribution of medium-small earthquakes in a long-term and a longer time are calculated for the analysis of anomalies before moderate and strong earthquakes. In the study region center on the epicenter of the 1989 Datong- Yanggao earthquake （Ms5. 9） within a radius of less than 0.8~, with the time length of 3600 days, the longer time length of 3700 days, and the time step of 100 days, the correlation coefficient from 1980 to 2009 is steady between 0.94 and 1.00, but there were anomalies with values less than 0. 94 in the 2 years before the 1989 Datong-Yanggao earthquake （Ms 5.9）, the 1991 Datong earthquake （ Ms 5.8） and 1999 Hunyuan earthquake （Ms 5. 6 ）, which indicates the spatial distribution of a medium-small earthquake is very different from steady background seismicity. The implication for earthquake prediction from the anomaly of the correlation coefficient is also discussed with the three conclusions： （1） Before moderate and strong earthquakes in Datong and its surrounding areas, the obvious change of spatial distribution patterns of medium-small earthquake can be a kind of seismic precursor of the 2-year time scale for the prediction of an earthquake＇s time. （2） As the study region is restricted within a radius of less than 0. 8~, the result of correlation analysis is also good for the prediction of an earthquake＇s location. （3） The method of correlation analysis in this paper helps recognize the anomaly of spatial distribution of medium-small earthquake.

编组应急分队宜“三定”

抓好民兵应急分队建设是民兵工作调整改革的重点之一。而要提高民兵应急分队的质量,在编组时宜实行“三定”:

Uncertainty in crossing time of 2 °C warming threshold over China

The 2 ℃ warming target has been used widely in global and regional climate change research. Previous studies have shown large uncertainties in the time when surface air temperature （SAT） change over China will reach 2℃ rela- tive to the pre-industrial era. To understand the uncertainties, we analyzed the projected SAT in the twenty-first century using 40 state-of-the-art climate models under two Repre- sentative Concentration Pathways （RCP4.5 and RCPS.5） from the Coupled Model Intercomparison Project Phase 5. The 2℃ threshold-crossing time （TCT） of SAT averaged across China was around 2033 and 2029 for RCP4.5 and RCP8.5, respectively. Considering a 4-1o- range of inter- model SAT change, the upper and lower bounds of the 2 ℃ TCT could differ by about 25 years or even more. Uncer- tainty in the projected SAT and the warming rate around the TCT are the two main factors responsible for the TCT uncertainty. The former is determined by the climate sensi- tivity represented by the global mean surface temperature response. About 45 % of the intermodel variance of the projected 2 ~C TCT for averaged SAT over China can be explained by climate sensitivity across the models, which is contributed mainly by central and southern China. In a cli- mate more sensitive to CO2 forcing, stronger greenhouse effect, less stratus cloud over the East Asian monsoon region, and less snow cover on the Tibetan Plateau result in increased downward longwave radiation, increased shortwave radia- tion, and decreased shortwave radiation reflected by the surface, respectively, all of which may advance the TCT.

A real-size MRPC developed for CBM-TOF

An MRPC prototype for the future CBM-TOF inner area has been developed.The counter assembled with low resistive glass consists of 10×0.22 mm gas gaps and 2×8 readout pads.The size of each pad is 20 mm×20 mm with an interval of 2 mm between pads.The signals of the counter are collected by 4 eight-pin connectors.Preliminary tests performed with cosmic-rays showed an efficiency over 98%and a time resolution around 60 ps.The measured crosstalk,dark current and dark rate were at a very low levels.Results under uniform irradiation performed at JINR with high energy deuteron showed a time resolution of40–50 ps and over 98%efficiency at a low flux rate,meanwhile at a flux up to 70 kHz/cm2,93%efficiency and 77 ps time resolution still remained.These excellent performances call fully meet the demand of CBM-TOF inner wall.

Landslide monitoring with high-resolution SAR data in the Three Gorges region

Employing the well-known D-InSAR technique,we investigated landslide monitoring in the Three Gorges region using TerraSAR-X data.The experiment demonstrates that using both the amplitude and differential phase allows us to identify the precise location,deformation and time range of occurrence of certain landslides.To overcome the atmospheric effect on D-InSAR results,a time-series analysis was also carried out.The observed nonlinear relationship between the deformation and water level suggests that reservoir water level fluctuation is one of the major causes of landslides,which is significant in terms of issuing landslide warnings.In addition,the comparison of TerraSAR-X and C-band ASAR data results indicates that TerraSAR-X data provide far more reasonable deformation measurements because of their high temporal and spatial resolutions.

General characteristics of climate changes during the past 2000 years in China

The general characteristics of climate changes over the past 2000 years in China,regional differences and uncertainties were analyzed based on the recently peer-reviewed high time-resolution climatic reconstructions.The results showed that there exists four warm periods of the temperature variation in China since the Qin Dynasty,including the western and eastern Han Dynasties(200 BC-AD 180),the Sui and Tang dynasties(541-810),the Song and Yuan dynasties(931-1320),and the 20th century,and three cold phases involving the Wei,Jin,and North-South Dynasties(181-540),the late Tang Dynasty(811-930),and the Ming and Qing dynasties(1321-1920).The Song and Yuan warm period is consistent with the Medieval Warm Period over the Northern Hemisphere,and the cold phases of the North-South Dynasties and the Ming and Qing dynasties are paralleled to the Dark Ages Cold Period and the Little Ice Age,respectively.The 13th-15th century could be a shift to the wet condition of the climate,and the low precipitation variability is exhibited in western China prior to 1500.In the context of the climate warming,the pattern of the drought in north and flood in south is prevalent over the eastern China.In addition,the published reconstructions have a high level of confidence for the past 500 years,but large uncertainties exist prior to the 16th century.

Analysis of the effect of regional lateral inflow on the flood peak of the Three Gorges Reservoir

The Three Gorges Region(TGR),located at the lower reach of the Upper Yangtze River Basin(UYRB) in China,suffers from heavy rainstorm frequently.The runoff generated from TGR composes an important part of the total flood at the famous Three Gorges Reservoir(TGRe).During the severe flood period in 1954,for example,the water from TGR accounted for up to 13.2% of the 30-days maximum flood volume of the UYRB.Considering the short and steep tributaries with rapid concentration,the regional lateral inflow(RLI) may induce more serious effect on the flood peak of the TGRe than the volume.However,hydrological data of the sparse gauge stations is too insufficient to evaluate the effect of RLI.This paper studied the impact by analyzing 880 flood events during 1956-2000.By comparing the observed hydrograph and simulated hydrograph with HEC-RAS software regarding no RLI,the effect of RLI on flood peak value and timing properties was identified and quantified.The variability of this effect among floods of different magnitudes was also analyzed.To evaluate the analysis uncertainty associated with the parameter of roughness coefficient,four sets of roughness coefficients from different research groups were employed in this study.The results showed that RLI contributes discharge of 3524 m3/s to flood peaks of the TGRe on average,with the contribution ratio of 15.9%.RLI contributes 12000 m3/s to the flood peaks larger than 50000 m3/s on average,with 25000 m3/s as its upper bound,while the contribution ratio can reach up to 50%,with an average of 20%.The variability of this effect is great among different events.Statistical analysis showed that to larger flood peak of the TGRe,RLI contributes more discharge with higher variability,and the contribution ratio and its variability are slightly larger,and events with higher contribution ratio occur more frequently.RLI can reshape the hydrograph,leading to earlier appearance of flood peak.This effect and its variability increase with the contribution ratio.This study has revealed that RLI plays an important role in large flood peak of the TGRe,which calls for more reliable flood forecasting methods to prolong the forecast lead time and improve the accuracy for the safety of the Three Gorges Dam and the protection of its lower reaches during severe flood disaster period.

Modeling the global ionospheric total electron content with empirical orthogonal function analysis

In the present work we model the global ionospheric total electron content (TEC) with the analysis of empirical orthogonal functions (EOF). The obtained statistical eigen modes, which makeup the modeled TEC, consist of two factors: the eigen vectors mapping TEC patterns at latitude and longitude (or local time LT), and the corresponding coefficients displaying the TEC variations in different time scales, i.e., the solar cycle, the yearly (annual and semiannual) and the diurnal universal time variations. It is found that the EOF analysis can separate the TEC variations into chief processes and the first two modes illustrate the most of the ionospheric climate properties. The first mode contains both the semiannual component which shows the semiannual ionospheric anomaly and the annual component which shows the annual or non-seasonal ionospheric anomaly. The second mode contains mainly the annual component and shows the normal seasonal ionospheric variation at most latitudes and local time sectors. The annual component in the second mode also manifests seasonal anomaly of the ionosphere at higher mid-latitudes around noontime. It is concluded that the EOF analysis, as a statistical eigen mode method, is resultful in analyzing the ionospheric climatology hence can be used to construct the empirical model for the ionospheric climatology.