期刊文献+
共找到14篇文章
< 1 >
每页显示 20 50 100
Reprocessing 12-yr Microwave Humidity Sounder Historical Data of Fengyun-3 Satellites
1
作者 Yang GUO Fangli DOU +5 位作者 Qiong WU Jieying HE Shengwei ZHANG Zhenzhan WANG Songyan GU Peng ZHANG 《Journal of Meteorological Research》 SCIE CSCD 2022年第2期261-270,共10页
Atmospheric water vapor is an essential climate variable(ECV)with extensive spatial and temporal variations.Microwave humidity observations from meteorological satellites provide important information for climate syst... Atmospheric water vapor is an essential climate variable(ECV)with extensive spatial and temporal variations.Microwave humidity observations from meteorological satellites provide important information for climate system variables,including atmospheric water vapor and precipitable water,and assimilation in numerical weather prediction(NWP)and reanalysis.As one of the payloads onboard China’s second-generation polar-orbiting operational meteorological Fengyun-3(FY-3)satellites,the Microwave Humidity Sounder(MWHS)has been continuously observing the global humidity since 2008.The reprocessing of historical FY-3 MWHS data is documented in detail in this study.After calibrating and correcting the data,the quality of the reprocessed dataset is evaluated and the improvement is shown in this study.The results suggest that MWHS observations bias is reduced to approximately 0.8 K,compared with METOP-A Microwave Humidity Sounder(MHS).The temporal variability of MWHS is highly correlated with the instrument temperature.After reprocessing,the scene temperature dependency is mitigated for all 183 GHz channels,and the consistency and stability between FY-3A/B/C are also improved. 展开更多
关键词 Fengyun-3 Microwave Humidity Sounder historical data reprocessing
原文传递
A Survey of Time Series Data Visualization Methods 被引量:1
2
作者 Wangdong Jiang Jie Wu +3 位作者 Guang Sun Yuxin Ouyang Jing Li Shuang Zhou 《Journal of Quantum Computing》 2020年第2期105-117,共13页
In the era of big data,the general public is more likely to access big data,but they wouldn’t like to analyze the data.Therefore,the traditional data visualization with certain professionalism is not easy to be accep... In the era of big data,the general public is more likely to access big data,but they wouldn’t like to analyze the data.Therefore,the traditional data visualization with certain professionalism is not easy to be accepted by the general public living in the fast pace.Under this background,a new general visualization method for dynamic time series data emerges as the times require.Time series data visualization organizes abstract and hard-to-understand data into a form that is easily understood by the public.This method integrates data visualization into short videos,which is more in line with the way people get information in modern fast-paced lifestyles.The modular approach also facilitates public participation in production.This paper summarizes the dynamic visualization methods of time series data ranking,studies the relevant literature,shows its value and existing problems,and gives corresponding suggestions and future research prospects. 展开更多
关键词 Dynamic visualization historical ranking of time series data VIDEO big data
下载PDF
Prediction of Commuter Vehicle Demand Torque Based on Historical Speed Information
3
作者 Shiji Sun Mingxin Kang Yuzhe Li 《Journal of Beijing Institute of Technology》 EI CAS 2022年第4期362-370,共9页
The development of vehicle-to-everything and cloud computing has brought new opportunities and challenges to the automobile industry.In this paper,a commuter vehicle demand torque prediction method based on historical... The development of vehicle-to-everything and cloud computing has brought new opportunities and challenges to the automobile industry.In this paper,a commuter vehicle demand torque prediction method based on historical vehicle speed information is proposed,which uses machine learning to predict and analyze vehicle demand torque.Firstly,the big data of vehicle driving is collected,and the driving data is cleaned and features extracted based on road information.Then,the vehicle longitudinal driving dynamics model is established.Next,the vehicle simulation simulator is established based on the longitudinal driving dynamics model of the vehicle,and the driving torque of the vehicle is obtained.Finally,the travel is divided into several accelerationcruise-deceleration road pairs for analysis,and the vehicle demand torque is predicted by BP neural network and Gaussian process regression. 展开更多
关键词 demand torque prediction commuter vehicle historical driving data machine learning
下载PDF
Fuzzy Logic Based Group Maturity Rating for Software Performance Prediction 被引量:2
4
作者 A.K.Verma Anil R Om Prakash Jain 《International Journal of Automation and computing》 EI 2007年第4期406-412,共7页
Driven by market requirements, software services organizations have adopted various software engineering process models (such as capability maturity model (CMM), capability maturity model integration (CMMI), ISO ... Driven by market requirements, software services organizations have adopted various software engineering process models (such as capability maturity model (CMM), capability maturity model integration (CMMI), ISO 9001:2000, etc.) and practice of the project management concepts defined in the project management body of knowledge. While this has definitely helped organizations to bring some methods into the software development madness, there always exists a demand for comparing various groups within the organization in terms of the practice of these defined process models. Even though there exist many metrics for comparison, considering the variety of projects in terms of technology, life cycle, etc., finding a single metric that caters to this is a difficult task. This paper proposes a model for arriving at a rating on group maturity within the organization. Considering the linguistic or imprecise and uncertain nature of software measurements, fuzzy logic approach is used for the proposed model. Without the barriers like technology or life cycle difference, the proposed model helps the organization to compare different groups within it with reasonable precision. 展开更多
关键词 Group maturity rating fuzzy logic fuzzy sets historical data software projects.
下载PDF
Long-Term Trends in Photosynthetically Active Radiation in Beijing 被引量:1
5
作者 胡波 王跃思 刘广仁 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2010年第6期1380-1388,共9页
A long-term dataset of photosynthetically active radiation (Qp) is reconstructed from a broadband global solar radiation (Rs) dataset through an all-weather reconstruction model. This method is based on four years... A long-term dataset of photosynthetically active radiation (Qp) is reconstructed from a broadband global solar radiation (Rs) dataset through an all-weather reconstruction model. This method is based on four years' worth of data collected in Beijing. Observation data of Rs and Qp from 2005-2008 are used to investigate the temporal variability of Qp and its dependence on the clearness index and solar zenith angle. A simple and effcient all-weather empirically derived reconstruction model is proposed to reconstruct Qp from Rs. This reconstruction method is found to estimate instantaneous Qp with high accuracy. The annual mean of the daily values of Qp during the period 1958-2005 period is 25.06 mol m-2 d-1. The magnitude of the long-term trend for the annual averaged Qp is presented (-0.19 mol m-2 yr-1 from 1958-1997 and -0.12 mol m-2 yr-1 from 1958-2005). The trend in Qp exhibits sharp decreases in the spring and summer and more gentle decreases in the autumn and winter. 展开更多
关键词 photosynthetically active radiation historical data reconstruction long-term trends
下载PDF
An Evaluation of the Main Physical Features and Circulation Patterns in the Black Sea Basin 被引量:1
6
作者 Alina Girleanu Eugen Rusu 《Journal of Marine Science》 2021年第1期8-18,共11页
Having as target the semi-enclosed basin of the Black Sea,the primary purpose of the existing paper is to present an overview of its extensive physical features and circulation patterns.To achieve this goal,more than ... Having as target the semi-enclosed basin of the Black Sea,the primary purpose of the existing paper is to present an overview of its extensive physical features and circulation patterns.To achieve this goal,more than five decades of data analysis-from 1960 to 2015-were taken into consideration and the results were validated against acknowledged data,both from satellite data over the last two decades and in-situ measurements from first decades.The circulation of the Black Sea basin has been studied for almost 400 years since the Italian Count Luigi Marsigli first described the“two-layer”circulation through the Bosphorus Strait in the year 1681.Since climate change projections for the Black Sea region foresee a significant impact on the environment in the coming decades,a set of adaptation and mitigation measures is required.Therefore more research is needed.Nowadays,the warming trend adds a sense of immediate urgency because according to the National Oceanic and Atmospheric Administration’s National Centre for Environmental Information,July 2020 was the second-hottest month ever recorded for the planet.Its averaged land and ocean surface temperature tied with July 2016 as the secondhighest for the month in the 141-year NOAA’s global temperature dataset history,which dates back to 1880.It was 0.92°C above the 20th-century average of 15.8°C,with only 0.01°C less than the record extreme value measured in July of 2019. 展开更多
关键词 Black Sea basin Circulation patterns historical data Climate change Extreme values
下载PDF
Eight predictive powers with historical and interim data for futility and efficacy analysis
7
作者 Ying-Ying Zhang Teng-Zhong Rong Man-Man Li 《Statistical Theory and Related Fields》 2022年第4期277-298,共22页
When the historical data of the early phase trial and the interim data of the Phase II trial are avail-able,we should use them to give a more accurate prediction in both futility and efficacy analysis.The predictive p... When the historical data of the early phase trial and the interim data of the Phase II trial are avail-able,we should use them to give a more accurate prediction in both futility and efficacy analysis.The predictive power is an important measure of the practical utility of a proposed trial,and it is better than the classical statistical power in giving a good indication of the probability that the trial will demonstrate a positive or statistically significant outcome.In addition to the four predic-tive powers with historical and interim data available in the literature and summarized in Table 1,we discover and calculate another four predictive powers also summarized in Table 1,for one-sided hypotheses.Moreover,we calculate eight predictive powers summarized in Table 2,for the reversed hypotheses.The combination of the two tables gives us a complete picture of the pre-dictive powers with historical and interim data for futility and efficacy analysis.Furthermore,the eight predictive powers with historical and interim data are utilized to guide the futility analysis in the tamoxifen example.Finally,extensive simulations have been conducted to investigate the sensitivity analysis of priors,sample sizes,interim result and interim time on different predictive powers. 展开更多
关键词 Predictive power historical data interim data futility and eficacy analysis phaseⅡ phaseⅢtrials
原文传递
Building Bayesian Network(BN)-Based System Reliability Model by Dual Genetic Algorithm(DGA)
8
作者 游威振 钟小品 《Journal of Donghua University(English Edition)》 EI CAS 2015年第6期914-918,共5页
A system reliability model based on Bayesian network(BN)is built via an evolutionary strategy called dual genetic algorithm(DGA).BN is a probabilistic approach to analyze relationships between stochastic events.In con... A system reliability model based on Bayesian network(BN)is built via an evolutionary strategy called dual genetic algorithm(DGA).BN is a probabilistic approach to analyze relationships between stochastic events.In contrast with traditional methods where BN model is built by professionals,DGA is proposed for the automatic analysis of historical data and construction of BN for the estimation of system reliability.The whole solution space of BN structures is searched by DGA and a more accurate BN model is obtained.Efficacy of the proposed method is shown by some literature examples. 展开更多
关键词 Bayesian network(BN)model dual genetic algorithm(DGA) system reliability historical data
下载PDF
Rotational Eustasy as Observed in Nature
9
作者 Nils-Axel Morner 《International Journal of Geosciences》 2019年第7期745-757,共13页
Observational facts from the Maldives, Goa and Bangladesh in the Indian Ocean and from Fiji and New Caledonia in the Pacific record a high sea level in the 17th century, a low sea level in the 18th century, a high sea... Observational facts from the Maldives, Goa and Bangladesh in the Indian Ocean and from Fiji and New Caledonia in the Pacific record a high sea level in the 17th century, a low sea level in the 18th century, a high sea level in the early 19th century and a stable sea level in the last 50 - 70 years. This cannot be understood in terms of glacial eustasy (or in terms of steric effects or tectonics), only in terms of rotational eustasy. The present paper gives a summary of the observational facts behind the formulation of the novel concept of rotational eustasy. It reveals a common trend of sea level changes, which is opposed to the sea level changes in the northern hemisphere, and the global climatic changes in general. Rotational eustasy offers a logical explanation. 展开更多
关键词 Sea Level Changes Rotational Eustasy Shore Morphology STRATIGRAPHY Biological Criteria historical data
下载PDF
Effect of Two Kinds of Similarity Factors on Principal Component Analysis Fault Detection in Air Conditioning Systems 被引量:2
10
作者 杨学宾 何如如 +1 位作者 王吉 罗雯军 《Journal of Donghua University(English Edition)》 CAS 2021年第3期245-251,共7页
Screening similar historical fault-free candidate data would greatly affect the effectiveness of fault detection results based on principal component analysis(PCA).In order to find out the candidate data,this study co... Screening similar historical fault-free candidate data would greatly affect the effectiveness of fault detection results based on principal component analysis(PCA).In order to find out the candidate data,this study compares unweighted and weighted similarity factors(SFs),which measure the similarity of the principal component subspace corresponding to the first k main components of two datasets.The fault detection employs the principal component subspace corresponding to the current measured data and the historical fault-free data.From the historical fault-free database,the load parameters are employed to locate the candidate data similar to the current operating data.Fault detection method for air conditioning systems is based on principal component.The results show that the weighted principal component SF can improve the effects of the fault-free detection and the fault detection.Compared with the unweighted SF,the average fault-free detection rate of the weighted SF is 17.33%higher than that of the unweighted,and the average fault detection rate is 7.51%higher than unweighted. 展开更多
关键词 similarity factor(SF) fault detection principal component analysis(PCA) historical candidate data air conditioning system
下载PDF
Towards Exploring Patterns of Editing Behavior on OpenStreetMap 被引量:2
11
作者 Zhiyao ZHAO Hongchao FAN 《Journal of Geodesy and Geoinformation Science》 2022年第2期85-97,共13页
OpenStreetMap has a large number of volunteers.There is a hypothesis that volunteers with different cultural backgrounds may have different editing behaviors when contributing to OSM.It may be strongly related to data... OpenStreetMap has a large number of volunteers.There is a hypothesis that volunteers with different cultural backgrounds may have different editing behaviors when contributing to OSM.It may be strongly related to data quality and data reliability on OSM.As for the heterogeneity and the reliability of OSM data,previous research usually focuses on the geometric accuracy,spatial location accuracy and semantic integrity of OSM data,while few researchers have analyzed these problems from the perspective of editing behavior.On the grounds of relationship between mapping motivation and editing behavior,the dispersion of editing trajectory and clockwise direction index are proposed in the paper to explore whether the volunteers are sufficiently motivated and knowledgeable.In the experiments,the historical OSM data of four countries suggested that developed countries have lower trajectory dispersion.The lower degree of trajectory dispersion reflects the higher concentration and professionalism of volunteers.A high degree of drawing direction consistency shows volunteers who mapped French data were natives with local knowledge.From this point of view,this paper verifies that volunteer editing behavior is an effective method to analyze data quality heterogeneity and data reliability. 展开更多
关键词 editing behavior historical OSM data data quality heterogeneity data reliability
下载PDF
Update on Fengyun Meteorological Satellite Program and Development 被引量:1
12
作者 ZHANG Peng CHEN Lin +2 位作者 XIAN Di XU Zhe GUAN Min 《空间科学学报》 CAS CSCD 北大核心 2020年第5期884-897,共14页
China began to develop its meteorological satellite program since 1969.With 50-years’growing,there are 17 Fengyun(FY)meteorological satellites launched successfully.At present,seven of them are in orbit to provide th... China began to develop its meteorological satellite program since 1969.With 50-years’growing,there are 17 Fengyun(FY)meteorological satellites launched successfully.At present,seven of them are in orbit to provide the operational service,including three polar orbiting meteorological satellites and four geostationary meteorological satellites.Since last COSPAR report,no new Fengyun satellite has been launched.The information of the on-orbit FY-2 series,FY-3 series,and FY-4 series has been updated.FY-3D and FY-2H satellites accomplished the commission test and transitioned into operation in 2018.FY-2E satellite completed its service to decommission in 2019.The web-based users and Direct Broadcasting(DB)users keep growing worldwide to require the Fengyun satellite data and products.A new Mobile Application Service has been launched to Fengyun users based on the cloud technology in 2018.In this report,the international and regional co-operations to facilitate the Fengyun user community have been addressed especially.To strengthen the data service in the Belt and Road countries,the Emergency Support Mechanism of Fengyun satellite(FY_ESM)has been established since 2018.Meanwhile,a Recalibrating 30-years’archived Fengyun satellite data project has been founded since 2018.This project targets to generate the Fundamental Climate Data Record(FCDR)as a space agency response to the Global Climate Observation System(GCOS).At last,the future Fengyun program up to 2025 has been introduced as well. 展开更多
关键词 Fengyun meteorological satellite Product and data service International co-operation and supporting historical Chinese Fengyun satellite data recalibrating Future program
下载PDF
The principle of coupled stress release model and its application 被引量:1
13
作者 刘杰 石耀林 庄建仓 《Acta Seismologica Sinica(English Edition)》 CSCD 1998年第3期9-17,共9页
oupled stress release model is proposed in the paper considering the interaction between different parts based on stress release model by VereJones, and is used to historical earthquake data from North China. The resu... oupled stress release model is proposed in the paper considering the interaction between different parts based on stress release model by VereJones, and is used to historical earthquake data from North China. The results by this model are compared with the results by original stress release model using AIC criterion. The results show that coupled stress release model is better than original model. 展开更多
关键词 coupled stress release model AIC criterion historical earthquake data in North China
下载PDF
Development of the Analogue-Dynamical Method for Error Correction of Numerical Forecasts 被引量:2
14
作者 于海鹏 黄建平 +1 位作者 李维京 封国林 《Journal of Meteorological Research》 SCIE 2014年第5期934-947,共14页
Due to the increasing requirement for high-level weather and climate forecasting accuracy, it is necessary to exploit a strategy for model error correction while developing numerical modeling and data assimilation tec... Due to the increasing requirement for high-level weather and climate forecasting accuracy, it is necessary to exploit a strategy for model error correction while developing numerical modeling and data assimilation techniques. This study classifies the correction strategies according to the types of forecast errors, and reviews recent studies on these correction strategies. Among others, the analogue-dynamical method has been developed in China, which combines statistical methods with the dynamical model, corrects model errors based on analogue information, and effectively utilizes historical data in dynamical forecasts. In this study, the fundamental principles and technical solutions of the analogue-dynamical method and associated development history for forecasts on different timescales are introduced. It is shown that this method can effectively improve medium- and extended-range forecasts, monthly-average circulation forecast, and short-term climate prediction. As an innovative technique independently developed in China, the analogue- dynamical method plays an important role in both weather forecast and climate prediction, and has potential applications in wider fields. 展开更多
关键词 analogue-dynamical method numerical model error correction historical data
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部