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Weighted Markov chains for forecasting and analysis in Incidence of infectious diseases in jiangsu Province,China 被引量:10
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作者 Zhihang Peng Changjun Bao +5 位作者 Yang Zhao Honggang Yi Letian Xia Hao Yu Hongbing Shen Feng Chen 《The Journal of Biomedical Research》 CAS 2010年第3期207-214,共8页
This paper first applies the sequential cluster method to set up the classification standard of infectious disease incidence state based on the fact that there are many uncertainty characteristics in the incidence cou... This paper first applies the sequential cluster method to set up the classification standard of infectious disease incidence state based on the fact that there are many uncertainty characteristics in the incidence course.Then the paper presents a weighted Markov chain,a method which is used to predict the future incidence state.This method assumes the standardized self-coefficients as weights based on the special characteristics of infectious disease incidence being a dependent stochastic variable.It also analyzes the characteristics of infectious diseases incidence via the Markov chain Monte Carlo method to make the long-term benefit of decision optimal.Our method is successfully validated using existing incidents data of infectious diseases in Jiangsu Province.In summation,this paper proposes ways to improve the accuracy of the weighted Markov chain,specifically in the field of infection epidemiology. 展开更多
关键词 weighted.Markov chains sequential cluster infectious diseases forecasting and analysis Markov chain Monte Carlo
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Analysis and forecasts of investment scale and structure in upstream sector for oil companies based on system dynamics 被引量:2
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作者 Zhang Baosheng Wang Qing 《Petroleum Science》 SCIE CAS CSCD 2011年第1期120-126,共7页
Oil and gas exploration and production is the most important and key segment in the whole business chain of the petroleum industry.Therefore,oil companies always put much emphasis on making scientific and reasonable d... Oil and gas exploration and production is the most important and key segment in the whole business chain of the petroleum industry.Therefore,oil companies always put much emphasis on making scientific and reasonable decisions about investment scale and structure in the upstream sector,so that they can minimise business risks and obtain high returns.According to the system dynamics theories and methods and based on the actual results from an oil company's practice in China,a system dynamics model is built in this paper for analyzing and forecasting the upstream investment scale and structure for an oil company.This model was used to analyze the investment effect of a large oil company in China, and the results showed that the total upstream investment scale will decline slowly in a short period and the investment proportion of different parts should be adjusted if some influencing factors are taken into account.This application practice was compared with the actual data and indicated that the system dynamics(SD) model presented in this paper is a useful tool for analyzing and forecasting of upstream investment scale and structure of oil companies in their investment decisions. 展开更多
关键词 Oil companies upstream investment scale and structure analysis and forecast system dynamics
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Analysis of an Unsuccessful Forecast for a Heavy Rainfall Event in Yingkou 被引量:1
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作者 HE Xiao-dong1, ZHAO Xiao-chuan1, ZHANG Hong-yu2, WANG Gui-jun1 1. Yingkou Meteorological Office, Yingkou 115001, China 2. Yingkou District of Hydrology and Water Resources Survey Bureau of Liaoning Province, Yingkou 115003, China 《Meteorological and Environmental Research》 CAS 2011年第4期50-52,56,共4页
[Objective] The reason for the unsuccessful forecast of a heavy rainfall event in Yingkou was analyzed. [Method] Based on the precipitation data observed by automatic weather stations and MICAPS data, a heavy rainfall... [Objective] The reason for the unsuccessful forecast of a heavy rainfall event in Yingkou was analyzed. [Method] Based on the precipitation data observed by automatic weather stations and MICAPS data, a heavy rainfall Event was studied in Yingkou from 19 July to 21 July in 2010. Then the analysis of an unsuccessful forecasting for the heavy rainfall on 21 July was illustrated by CINRAD-SA data, satellite data and numerical forecast products. [Result] The main reason for the unsuccessful forecast was that the duration of the rainfall was long and inconsecutive. The distribution was uneven. Strong precipitation on 21st was different from the one in previous two durations. It was regional short term strong precipitation. And the forecast difficulty was large; the numerical forecast was unstable and erroneous;strong precipitation occurred in the night on 20th, which was shortly before the strong precipitation in the evening of 21st. This would easily confuse the reporter. Besides, the short term stillness of radar and cloud during this time would form certain disturbance. The focus of rainstorm forecast should based on the numerical forecast instead of element forecast;insisting on situation analysis and taking element judgment as auxiliary;as for strong precipitation forecast, there was large error in numerical forecast and can not be relied. Reporter should report the correct one based on experience. [Conclusion] The study provided reference for the forecast of rainstorm. 展开更多
关键词 Heavy rainfall analysis of unsuccessful forecasting Forecast starting points Yingkou China
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Application test of matter element analysis in earthquake forecast 被引量:1
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作者 LI HUA FENG Department of Geography, Zhejiang Normal University, Jinhua 321004, China 《Acta Seismologica Sinica(English Edition)》 CSCD 1998年第6期89-94,共6页
Calculation by means of the previous indices of the seismic activity can have the matter element analysis possess the forecast function. Readjusting repeatedly the grade limit value of every index can maximize the his... Calculation by means of the previous indices of the seismic activity can have the matter element analysis possess the forecast function. Readjusting repeatedly the grade limit value of every index can maximize the historical fitting ratio of the calculated and actual grade of the annual maximum magnitude, whose result is relatively ideal. 展开更多
关键词 correlation function matter element analysis annual maximum magnitude earthquake forecast
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Analysis of Chinese Power Market in 2007 and Its Forecast
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作者 Department of Development and Planning, State Grid Corporation, and State Power Economic Research Institute Jia Yulu 《Electricity》 2008年第2期41-45,共5页
Power supply and demand inJanuary-September, 2007Since 2007, the national economy developed continu-ously, showing a situation of rapid growth, more optimizedstructure, increased efficiency and improvement of people&#... Power supply and demand inJanuary-September, 2007Since 2007, the national economy developed continu-ously, showing a situation of rapid growth, more optimizedstructure, increased efficiency and improvement of people'slivelihood. In the first three quarters, GDP achieved 16.6043trillion Yuan, and its year-on-year growth rate was 11.5%; 展开更多
关键词 WILL analysis of Chinese Power Market in 2007 and Its Forecast rate THAN
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Tidal Level Response to Sea-Level Rise in the Yangtze Estuary 被引量:5
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作者 龚政 张长宽 +1 位作者 万里明 左军成 《China Ocean Engineering》 SCIE EI 2012年第1期109-122,共14页
The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary. This paper focuses on the variations of tidal level response ... The rise of tidal level in tidal reaches induced by sea-level rise has a large impact on flood control and water supply for the regions around the estuary. This paper focuses on the variations of tidal level response along the tidal reaches in the Yangtze Estuary, as well as the impacts of upstream discharge on tidal level response, due to the sea-level rise of the East China Sea. Based on the Topex/Poseidon altimeter data obtained during the period 1993-2005, a stochastic dynamic analysis was performed and a forecast model was run to predict the sea-level rise of the East China Sea. Two- dimensional hydrodynamic numerical models downscaling from the East China Sea to estuarine areas were implemented to analyze the rise of tidal level along the tidal reaches. In response to the sea-level rise, the tidal wave characteristics change slightly in nearshore areas outside the estuaries, involving the tidal range and the duration of flood and ebb tide. The results show that the rise of tidal level in the tidal reaches due to the sea-level rise has upstream decreasing trends. The step between the stations of Zhangjiagang and Shiyiwei divides the tidal reaches into two parts, in which the tidal level response declines slightly. The rise of tidal level is 1-2.5 mm/a in the upper part, and 4-6 mm/a in the lower part. The stations of Jiangyin and Yanglin, as an example of the upper part and the lower part respectively, are extracted to analyze the impacts of upstream discharge on tidal level response to the sea-level rise. The relation between the rise of tidal level and the upstream discharge can be fitted well with a quadratic fimction in the upper part. However, the relation is too complicated to be fitted in the lower part because of the tide dominance. For comparison purposes, hourly tidal level observations at the stations of Xuliujing and Yanglin during the period 1993-2009 are adopted. In order to uniform the influence of upstream discharge on tidal level for a certain day each year, the hourly tidal level observations are corrected by the correlation between the increment of tidal level and the increment of daily mean upstream discharge. The rise of annual mean tidal level is evaluated. The resulting rise of tidal level at the stations of Xuliujing and Yanglin is 3.0 mm/a and 6.6 mm/a respectively, close to the rise of 5 mm/a according to the proposed relation between the rise of tidal level and the upstream discharge. 展开更多
关键词 Yangtze Estuary sea-level r&e stochastic dynamic analysis and forecast model tidal reaches dischargeincrement
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Analyses and Forecasts of a Tornadic Supercell Outbreak Using a 3DVAR System Ensemble
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作者 Zhaorong ZHUANG Nusrat YUSSOUF Jidong GAO 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2016年第5期544-558,共15页
As part of NOAA's "Warn-On-Forecast" initiative, a convective-scale data assimilation and prediction system was developed using the WRF-ARW model and ARPS 3DVAR data assimilation technique. The system was then eval... As part of NOAA's "Warn-On-Forecast" initiative, a convective-scale data assimilation and prediction system was developed using the WRF-ARW model and ARPS 3DVAR data assimilation technique. The system was then evaluated using retrospective short-range ensemble analyses and probabilistic forecasts of the tornadic supercell outbreak event that occurred on 24 May 2011 in Oklahoma, USA. A 36-member multi-physics ensemble system provided the initial and boundary conditions for a 3-km convective-scale ensemble system. Radial velocity and reflectivity observations from four WSR-88 Ds were assimilated into the ensemble using the ARPS 3DVAR technique. Five data assimilation and forecast experiments were conducted to evaluate the sensitivity of the system to data assimilation frequencies, in-cloud temperature adjustment schemes, and fixed- and mixed-microphysics ensembles. The results indicated that the experiment with 5-min assimilation frequency quickly built up the storm and produced a more accurate analysis compared with the 10-min assimilation frequency experiment. The predicted vertical vorticity from the moist-adiabatic in-cloud temperature adjustment scheme was larger in magnitude than that from the latent heat scheme. Cycled data assimilation yielded good forecasts, where the ensemble probability of high vertical vorticity matched reasonably well with the observed tornado damage path. Overall, the results of the study suggest that the 3DVAR analysis and forecast system can provide reasonable forecasts of tornadic supercell storms. 展开更多
关键词 ensemble 3DVAR analysis radar data assimilation probabilistic forecast supercell storm
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An air quality forecasting system in Beijing-Application to the study of dust storm events in China in May 2008 被引量:9
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作者 Benoit Laurent Fanny Velay-Lasry +3 位作者 Richard Ngo Claude Derognat Batrice Marticorena Armand Albergel 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2012年第1期102-111,共10页
An air pollution forecast system,ARIA Regional,was implemented in 2007–2008 at the Beijing Municipality Environmental Monitoring Center,providing daily forecast of main pollutant concentrations.The chemistry-transpor... An air pollution forecast system,ARIA Regional,was implemented in 2007–2008 at the Beijing Municipality Environmental Monitoring Center,providing daily forecast of main pollutant concentrations.The chemistry-transport model CHIMERE was coupled with the dust emission model MB95 for restituting dust storm events in springtime so as to improve forecast results.Dust storm events were sporadic but could be extremely intense and then control air quality indexes close to the source areas but also far in the Beijing area.A dust episode having occurred at the end of May 2008 was analyzed in this article,and its impact of particulate matter on the Chinese air pollution index (API) was evaluated.Following our estimation,about 23 Tg of dust were emitted from source areas in Mongolia and in the Inner Mongolia of China,transporting towards southeast.This episode of dust storm influenced a large part of North China and East China,and also South Korea.The model result was then evaluated using satellite observations and in situ data.The simulated daily concentrations of total suspended particulate at 6:00 UTC had a similar spatial pattern with respect to OMI satellite aerosol index.Temporal evolution of dust plume was evaluated by comparing dust aerosol optical depth (AOD) calculated from the simulations with AOD derived from MODIS satellite products.Finally,the comparison of reported Chinese API in Beijing with API calculated from the simulation including dust emissions had showed the significant improvement of the model results taking into accountmineral dust correctly. 展开更多
关键词 DUST particulate matter modeling BEIJING air quality forecast and analysis system
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Forecast and Analysis of China's Lithium Battery Industry in the Next 5 Years
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《China Nonferrous Metals Monthly》 2017年第3期1-3,共3页
Ⅰ.Favorable factors(Ⅰ)Unveiling of industry norms and standards In the recent several years,portable power charger and portable power bank experienced rapid development,the market is brisk,it is supported by extreme... Ⅰ.Favorable factors(Ⅰ)Unveiling of industry norms and standards In the recent several years,portable power charger and portable power bank experienced rapid development,the market is brisk,it is supported by extremely wide population groups for application.Since portable power bank has low access requirements,the industry also 展开更多
关键词 Forecast and analysis of China’s Lithium Battery Industry in the Next 5 Years
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