The Tahiti-Darwin Southern Oscillation index provided by Climate Analysis Center of USA has been used in numerous studies. But, it has some deficiency. It contains noise mainly due to high month-to-month variability. ...The Tahiti-Darwin Southern Oscillation index provided by Climate Analysis Center of USA has been used in numerous studies. But, it has some deficiency. It contains noise mainly due to high month-to-month variability. In order to reduce the level of noise in the SO index, this paper introduces a fully data-adaptive filter based on singular spectrum analysis. Another interesting aspect of the filter is that it can be used to fill data gaps of the SO index by an iterative process. Eventually, a noiseless long-period data series without any gaps is obtained.展开更多
Background: Tropical forests play a fundamental role in the provision of diverse ecosystem services, such as biodiversity,climate and air quality regulation, freshwater provision, carbon cycling, agricultural support ...Background: Tropical forests play a fundamental role in the provision of diverse ecosystem services, such as biodiversity,climate and air quality regulation, freshwater provision, carbon cycling, agricultural support and culture. To understand the role of forests in the carbon balance, aboveground biomass(AGB) estimates are needed. Given the importance of Brazilian tropical forests, there is an urgent need to improve AGB estimates to support the Brazilian commitments under the United Nations Framework Convention on Climate Change(UNFCCC). Many AGB maps and datasets exist, varying in availability, scale and coverage. Thus, stakeholders, policy makers and scientists must decide which AGB product, dataset or combination of data to use for their particular goals. In this study, we assessed the gaps in the spatial AGB data across the Brazilian Amazon forests not only to orient the decision makers about the data that are currently available but also to provide a guide for future initiatives.Results: We obtained a map of the gaps in the forest AGB spatial data for the Brazilian Amazon using statistics and differences between AGB maps and a spatial multicriteria evaluation that considered the current AGB datasets. The AGB spatial data gap map represents areas with good coverage of AGB data and, consequently, the main gaps or priority areas where further biomass assessments should focus, including the northeast of Amazon State, Amapá and northeast of Pará. Additional y, by quantifying the variability in both the AGB maps and field data on multiple environmental factors,we provide valuable elements for understanding the current AGB data as a function of climate, soil, vegetation and geomorphology.Conclusions: The map of AGB data gaps could become a useful tool for policy makers and different stakeholders working on National Communications, Reducing Emissions from Deforestation and Degradation(REDD+), or carbon emissions modeling to prioritize places to implement further AGB assessments. Only 0.2% of the Amazon biome forest is sampled, and extensive effort is necessary to improve what we know about the tropical forest.展开更多
International disaster databases and catalogs provide a baseline for researchers,governments,communities,and organizations to understand the risk of a particular place,analyze broader trends in disaster risk,and justi...International disaster databases and catalogs provide a baseline for researchers,governments,communities,and organizations to understand the risk of a particular place,analyze broader trends in disaster risk,and justify investments in mitigation.Perhaps because Singapore is routinely identified as one of the safest countries in the world,Singapore’s past disasters have not been studied extensively with few events captured in major global databases such as EM-DAT.In this article,we fill the disaster data gap for postwar Singapore(1950–2020)using specified metrics through an archival search,review of literature,and analysis of secondary sources.We present four key lessons from cataloging these events.First,we expand Singapore’s disaster catalog to 39 events in this time period and quantify the extent of this data gap.Second,we identify the mitigating actions that have followed past events that contribute to Singapore’s present-day safety.Third,we discuss how these past events uncover continuities among vulnerability bearers in Singapore.Last,we identify limitations of a disaster catalog when considering future risks.In expanding the disaster catalog,this case study of Singapore supports the need for comprehensive understanding of past disasters in order to examine current and future disaster resilience.展开更多
Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data...Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data model,and empirically tested the impacts of agricultural TFP on the income gap between urban and rural residents. The results show that the improvement in agricultural TFP can promote the narrowing of the income gap between urban and rural residents,and the factors such as urbanization level and industrial structure also have significant impacts on the income gap between urban and rural residents. On the basis of these,it came up with recommendations,including increasing agricultural human capital investment and establishing agricultural production research institutions.展开更多
随着电力系统中可再生能源(renewable energy sources,RESs)比例不断增加,新能源参与能量市场和备用市场在技术上和经济上的重要性不断凸显。研究了含有风、光、水、储资源的RES聚合商在日前市场、备用市场及实时平衡市场等多个市场的...随着电力系统中可再生能源(renewable energy sources,RESs)比例不断增加,新能源参与能量市场和备用市场在技术上和经济上的重要性不断凸显。研究了含有风、光、水、储资源的RES聚合商在日前市场、备用市场及实时平衡市场等多个市场的综合竞价策略。针对北欧顺序交易市场框架,提出了一套考虑备用资源和波动补偿耦合的数据驱动信息间隙理论(data-driven information gap theory,DIGDT)决策模型解决RES聚合商的多阶段竞价优化问题。在DIGDT中采用基于置信区间的模糊集构造方法(confidence interval-based ambiguity set,CIAS)估计风、光的预测误差,通过机会约束对水电和储能(batteryenergy storage,BES)补偿出力偏差的可能性进行建模,并考虑备用资源与补偿容量的多时间尺度耦合。在备用市场中,利用基于备用调用场景的随机优化确保日前备用计划的可行性。通过案例分析验证了所提出模型的有效性。展开更多
In this paper, the AMSAA-BISE model with missing data is discussed. The ML estimates of model parameters and current MTBF are given, and the chi-squared test and a plot for cumulative number of failures versus cumulat...In this paper, the AMSAA-BISE model with missing data is discussed. The ML estimates of model parameters and current MTBF are given, and the chi-squared test and a plot for cumulative number of failures versus cumulative testing time are used to test the goodness of fit for the model. This paper concludes with a numerical example to verify the model.展开更多
Resource utilization efficiency is one of important factors influencing modern agricultural development. This paper evaluates agricultural resource utilization efficiency of Hebei Province in the Eleventh Five-Year Pl...Resource utilization efficiency is one of important factors influencing modern agricultural development. This paper evaluates agricultural resource utilization efficiency of Hebei Province in the Eleventh Five-Year Plan period by dynamic comprehensive evaluation method. Evaluation results indicate that regional disparity in agricultural resource utilization efficiency is significant, and the disparity is increasing year by year.展开更多
Recurrent event gap times data frequently arise in biomedical studies and often more than one type of event is of interest. To evaluate the effects of covariates on the marginal recurrent event hazards functions, ther...Recurrent event gap times data frequently arise in biomedical studies and often more than one type of event is of interest. To evaluate the effects of covariates on the marginal recurrent event hazards functions, there exist two types of hazards models： the multiplicative hazards model and the additive hazards model. In the paper, we propose a more flexible additive-multiplicative hazards model for multiple type of recurrent gap times data, wherein some covariates are assumed to be additive while others are multiplicative. An estimating equation approach is presented to estimate the regression parameters. We establish asymptotic properties of the proposed estimators.展开更多
文摘The Tahiti-Darwin Southern Oscillation index provided by Climate Analysis Center of USA has been used in numerous studies. But, it has some deficiency. It contains noise mainly due to high month-to-month variability. In order to reduce the level of noise in the SO index, this paper introduces a fully data-adaptive filter based on singular spectrum analysis. Another interesting aspect of the filter is that it can be used to fill data gaps of the SO index by an iterative process. Eventually, a noiseless long-period data series without any gaps is obtained.
基金part of the Sao Paulo Research Foundation (FAPESP) Grant No.2013/20616–6 and 2018/18493–7the project LiDAR Remote Sensing of Brazilian Amazon Forests:Analysis of Forest Biomass,Forest Degradation,and Secondary Regrowth funded by the USAID Prime Award Number AID-OAA-A-11-00012。
文摘Background: Tropical forests play a fundamental role in the provision of diverse ecosystem services, such as biodiversity,climate and air quality regulation, freshwater provision, carbon cycling, agricultural support and culture. To understand the role of forests in the carbon balance, aboveground biomass(AGB) estimates are needed. Given the importance of Brazilian tropical forests, there is an urgent need to improve AGB estimates to support the Brazilian commitments under the United Nations Framework Convention on Climate Change(UNFCCC). Many AGB maps and datasets exist, varying in availability, scale and coverage. Thus, stakeholders, policy makers and scientists must decide which AGB product, dataset or combination of data to use for their particular goals. In this study, we assessed the gaps in the spatial AGB data across the Brazilian Amazon forests not only to orient the decision makers about the data that are currently available but also to provide a guide for future initiatives.Results: We obtained a map of the gaps in the forest AGB spatial data for the Brazilian Amazon using statistics and differences between AGB maps and a spatial multicriteria evaluation that considered the current AGB datasets. The AGB spatial data gap map represents areas with good coverage of AGB data and, consequently, the main gaps or priority areas where further biomass assessments should focus, including the northeast of Amazon State, Amapá and northeast of Pará. Additional y, by quantifying the variability in both the AGB maps and field data on multiple environmental factors,we provide valuable elements for understanding the current AGB data as a function of climate, soil, vegetation and geomorphology.Conclusions: The map of AGB data gaps could become a useful tool for policy makers and different stakeholders working on National Communications, Reducing Emissions from Deforestation and Degradation(REDD+), or carbon emissions modeling to prioritize places to implement further AGB assessments. Only 0.2% of the Amazon biome forest is sampled, and extensive effort is necessary to improve what we know about the tropical forest.
基金We would like to acknowledge support from the National Research Foundation,Prime Minister's Office,Singapore under the NRF2018-SR2001-007 and NRF-NRFF2018-06 awardsThis research is also partly supported by the National Research Foundation Singaporethe Singapore Ministry of Education under the Research Centres of Excellence initiative through the Earth Observatory of Singapore
文摘International disaster databases and catalogs provide a baseline for researchers,governments,communities,and organizations to understand the risk of a particular place,analyze broader trends in disaster risk,and justify investments in mitigation.Perhaps because Singapore is routinely identified as one of the safest countries in the world,Singapore’s past disasters have not been studied extensively with few events captured in major global databases such as EM-DAT.In this article,we fill the disaster data gap for postwar Singapore(1950–2020)using specified metrics through an archival search,review of literature,and analysis of secondary sources.We present four key lessons from cataloging these events.First,we expand Singapore’s disaster catalog to 39 events in this time period and quantify the extent of this data gap.Second,we identify the mitigating actions that have followed past events that contribute to Singapore’s present-day safety.Third,we discuss how these past events uncover continuities among vulnerability bearers in Singapore.Last,we identify limitations of a disaster catalog when considering future risks.In expanding the disaster catalog,this case study of Singapore supports the need for comprehensive understanding of past disasters in order to examine current and future disaster resilience.
文摘Taking the relevant data of 27 provinces in China during 2013 and 2017 as samples,this paper firstly measured the agricultural total factor productivity( TFP) using Malmquist index method. Then,it built the panel data model,and empirically tested the impacts of agricultural TFP on the income gap between urban and rural residents. The results show that the improvement in agricultural TFP can promote the narrowing of the income gap between urban and rural residents,and the factors such as urbanization level and industrial structure also have significant impacts on the income gap between urban and rural residents. On the basis of these,it came up with recommendations,including increasing agricultural human capital investment and establishing agricultural production research institutions.
文摘随着电力系统中可再生能源(renewable energy sources,RESs)比例不断增加,新能源参与能量市场和备用市场在技术上和经济上的重要性不断凸显。研究了含有风、光、水、储资源的RES聚合商在日前市场、备用市场及实时平衡市场等多个市场的综合竞价策略。针对北欧顺序交易市场框架,提出了一套考虑备用资源和波动补偿耦合的数据驱动信息间隙理论(data-driven information gap theory,DIGDT)决策模型解决RES聚合商的多阶段竞价优化问题。在DIGDT中采用基于置信区间的模糊集构造方法(confidence interval-based ambiguity set,CIAS)估计风、光的预测误差,通过机会约束对水电和储能(batteryenergy storage,BES)补偿出力偏差的可能性进行建模,并考虑备用资源与补偿容量的多时间尺度耦合。在备用市场中,利用基于备用调用场景的随机优化确保日前备用计划的可行性。通过案例分析验证了所提出模型的有效性。
文摘In this paper, the AMSAA-BISE model with missing data is discussed. The ML estimates of model parameters and current MTBF are given, and the chi-squared test and a plot for cumulative number of failures versus cumulative testing time are used to test the goodness of fit for the model. This paper concludes with a numerical example to verify the model.
基金Supported by Hebei Province Philosophy and Social Science Planning Project in 2011(201102002)
文摘Resource utilization efficiency is one of important factors influencing modern agricultural development. This paper evaluates agricultural resource utilization efficiency of Hebei Province in the Eleventh Five-Year Plan period by dynamic comprehensive evaluation method. Evaluation results indicate that regional disparity in agricultural resource utilization efficiency is significant, and the disparity is increasing year by year.
基金The Science Foundation(JA12301)of Fujian Educational Committeethe Teaching Quality Project(ZL0902/TZ(SJ))of Higher Education in Fujian Provincial Education Department
文摘Recurrent event gap times data frequently arise in biomedical studies and often more than one type of event is of interest. To evaluate the effects of covariates on the marginal recurrent event hazards functions, there exist two types of hazards models： the multiplicative hazards model and the additive hazards model. In the paper, we propose a more flexible additive-multiplicative hazards model for multiple type of recurrent gap times data, wherein some covariates are assumed to be additive while others are multiplicative. An estimating equation approach is presented to estimate the regression parameters. We establish asymptotic properties of the proposed estimators.
