With the rapid growth of the Internet and social media, information is widely disseminated in multimodal forms, such as text and images, where discriminatory content can manifest in various ways. Discrimination detect...With the rapid growth of the Internet and social media, information is widely disseminated in multimodal forms, such as text and images, where discriminatory content can manifest in various ways. Discrimination detection techniques for multilingual and multimodal data can identify potential discriminatory behavior and help foster a more equitable and inclusive cyberspace. However, existing methods often struggle in complex contexts and multilingual environments. To address these challenges, this paper proposes an innovative detection method, using image and multilingual text encoders to separately extract features from different modalities. It continuously updates a historical feature memory bank, aggregates the Top-K most similar samples, and utilizes a Gated Recurrent Unit (GRU) to integrate current and historical features, generating enhanced feature representations with stronger semantic expressiveness to improve the model’s ability to capture discriminatory signals. Experimental results demonstrate that the proposed method exhibits superior discriminative power and detection accuracy in multilingual and multimodal contexts, offering a reliable and effective solution for identifying discriminatory content.展开更多
A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development targ...A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development target China Dream.Results showed that 1)toward the 2050 China Dream target,total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050,whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050;2)the proportion of non-fossil fuels is expected to reach approximately 50%and that of natural gas to reach more than 16%by 2050;3)CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.展开更多
Geographic location of nodes is very useful in a sensor network. Previous localization algorithms assume that there exist some anchor nodes in this kind of network, and then other nodes are estimated to create their c...Geographic location of nodes is very useful in a sensor network. Previous localization algorithms assume that there exist some anchor nodes in this kind of network, and then other nodes are estimated to create their coordinates. Once there are not anchors to be deployed, those localization algorithms will be invalidated. Many papers in this field focus on anchor-based solutions. The use of anchors introduces many limitations, since anchors require external equipments such as global position system, cause additional power consumption. A novel positioning algorithm is proposed to use a virtual coordinate system based on a new concept--virtual anchor. It is executed in a distributed fashion according to the connectivity of a node and the measured distances to its neighbors. Both the adjacent member information and the ranging distance result are combined to generate the estimated position of a network, one of which is independently adopted for localization previously. At the position refinement stage the intermediate estimation of a node begins to be evaluated on its reliability for position mutation; thus the positioning optimization process of the whole network is avoided falling into a local optimal solution. Simulation results prove that the algorithm can resolve the distributed localization problem for anchor-free sensor networks, and is superior to previous methods in terms of its positioning capability under a variety of circumstances.展开更多
Resources and environment carrying capacity is central to not only regional sustainable development but also major function-oriented zoning. This paper presents an evaluation index system for resources and environment...Resources and environment carrying capacity is central to not only regional sustainable development but also major function-oriented zoning. This paper presents an evaluation index system for resources and environment carrying capacity based on four aspects of carrying capacity(i.e., water resources, land resources, the environment, and ecosystems) by using a square deviation decision-making method, and on the basis of above effort evaluates the resources and environment carrying capacity across 31 provincial regions in China(not including Hong Kong, Macao and Taiwan regions of China). In addition, this paper evaluates the current state of socio-economic development, and analyzes the spatial distribution of resources and environment pressure. The results showed that distinct spatial differences in resources and environment carrying capacity and pressure across provincial regions. Resources and environment pressure is affected by both comprehensive resources and environment carrying capacity and socio-economic development. Regions subjected to lower degrees of resources and environment pressure will be restricted by resources and environmental problems through future courses of development owing to excessively low carrying capacities. By contrast, regions with higher comprehensive resources and environment carrying capacity will be subjected to excessively high levels of resources and environment pressure because of rapid socio-economic development. Both of resources and environment carrying capacity and pressure must therefore be considered in the allocation of country-binding targets to provincial regions.展开更多
Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other han...Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies.展开更多
The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and indust...The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and industry-level energy models and compared.The CO2 emission trends in the considered scenarios peak from 2015 to 2030 at the level of 9e11 Gt.Sector-level analysis suggests that total emissions pathways before 2030 will be determined mainly by dynamics of emissions in the electric power industry and transportation sector.Both sectors will experience significant increase in demand,but have low-carbon alternative options for development.Based on a side-by-side comparison of modeling input and results,conclusions have been drawn regarding the sources of emissions projections differences,which include data,views on economic perspectives,or models'structure and theoretical framework.Some suggestions have been made regarding energy models'development priorities for further research.展开更多
Based on the survey of international emissions trading system （ETS） and quantitative analysis, policy suggestions on establishing a carbon ETS in China are presented in this study. Sectors sensitive to carbon prices...Based on the survey of international emissions trading system （ETS） and quantitative analysis, policy suggestions on establishing a carbon ETS in China are presented in this study. Sectors sensitive to carbon prices, e.g., the power generation sector and the iron and steel industry, are given priority to be covered by the ETS. Interregional carbon trading should be carried out as early as possible. The cap of the ETS should be based on China＇s carbon intensity reduction target with the floor carbon price for the market being set in the beginning. Suggestions on the infrastructure of ETS are also proposed, including the national wide carbon measuring, reporting, verification system building. account registration system and the legislation to national展开更多
This study focuses on a national regional coordinated development strategy and adopts China Multi-Regional Computable General Equilibrium model to analyze the economic and social development, energy demand, and carbon...This study focuses on a national regional coordinated development strategy and adopts China Multi-Regional Computable General Equilibrium model to analyze the economic and social development, energy demand, and carbon emissions of the provinces during the 14th Five-Year Plan (FYP, 2021 2025) period based on the economic development and energy demand since the New Normal. The main conclusions are the following: 1) Under the guidance of the regional coordinated development strategy, 13 provinces/municipalities are expected to have a per capita gross domestic product (GDP) of more than US$15,000, and 16 provinces/municipalities will have a per capita GDP of US$10,000 15,000. All provincial economies are expected to achieve steady and rapid development by the end of the 14th FYP. 2) The total energy consumption of the provinces is expected to reach 5.45 Gtce (excluding Tibet) in 2025, and the average annual growth rate is approximately 1.5%. The growth of energy demand will remain in low speed. The key point of energy demand will gradually shift from the eastern to the middle area, while the proportion of energy use in the western provinces will remain stable, which is consistent with the economic development stage and regional coordinated development strategy. 3) The annual average carbon intensity (mainly considering carbon emissions from energy use) of the provinces will approximately with most provinces dropping by over 4.0%. The trend of a considerable decline in carbon intensity, as observed in recent years, is expected to continue.展开更多
To avoid the curse of dimensionality, text categorization （TC） algorithms based on machine learning （ML） have to use an feature selection （FS） method to reduce the dimensionality of feature space. Although havin...To avoid the curse of dimensionality, text categorization （TC） algorithms based on machine learning （ML） have to use an feature selection （FS） method to reduce the dimensionality of feature space. Although having been widely used, FS process will generally cause information losing and then have much side-effect on the whole performance of TC algorithms. On the basis of the sparsity characteristic of text vectors, a new TC algorithm based on lazy feature selection （LFS） is presented. As a new type of embedded feature selection approach, the LFS method can greatly reduce the dimension of features without any information losing, which can improve both efficiency and performance of algorithms greatly. The experiments show the new algorithm can simultaneously achieve much higher both performance and efficiency than some of other classical TC algorithms.展开更多
This paper examines the impact of climate change on China＇s grain production and food security. The research is one of the four studies on future conditions of China＇s food production system under the influence of c...This paper examines the impact of climate change on China＇s grain production and food security. The research is one of the four studies on future conditions of China＇s food production system under the influence of climate change using numerical simulation methods, carried out under a national 973 project entitled ＂impacts of climate change on food systems in China and its adaptation＂. The other three studies focus on changes in cultivated land area and food production, while this study incorporates their grain yield results into a general equilibrium model to simulate future conditions of the grain market. Our simulation analysis arrives at the impact of climate change by comparing such economic variables as grain production, consumption, and GDP growth rate between a baseline scenario and two climate change scenarios. Our results are summarized as follows： （1） In 2050, the total grain production will reach 689.683 million tons--584.264 million tons of total grain consumption and 42.808 million tons of exports. Without considering losses and inventory demand, in 2050 China＇s grain supply and demand will remain well balanced, with a slight surplus expected. （2） Climate change is expected to benefit China＇s macro economy and individual sectors. In comparison with the baseline scenario of no climate change, real wage, real GDP, investment, household consumption, exports, and other macroeconomic indicators will rise under the climate change scenarios. As far as the agricultural, manufacturing, and service sectors are concerned, production, consumption, imports, and exports will each be favorably affected by climate change. （3） The favorable impact of climate change on China＇s macroeconomy and individual sectors under the high emissions scenario （A2） is stronger than that under the low emissions scenario （B2）. （4） In the grain market, climate change is expected to increase supply, reduce imports, increase supply, and demand; and supply will increase more than demand does. All in all, if taking into the fertilization effect of CO2 account, climate change is expected to strengthen China＇s grain supply and safeguard food security.展开更多
The purpose of this work is to study the principle fluctuation modes of the global stock market,which is regarded as a complex system.It is proposed that the systematic risk can be reflected by the trace calculated fr...The purpose of this work is to study the principle fluctuation modes of the global stock market,which is regarded as a complex system.It is proposed that the systematic risk can be reflected by the trace calculated from the cross-correlation matrix,and the integrity can be classified into clusters according to the plus-minus signs of the elements of the eigenvectors corresponding to several top largest eigenvalues whose total value accounts for more than 60 percent of the trace.The principle fluctuation modes of 30 stock markets are in the same direction in each year of 2005-2010.According to the classification criteria proposed here,the stock markets of the Americas,Europe and Asia & Oceania are automatically classified into different clusters,while Brazil,Russia and China are separated.展开更多
In network environments,before meaningful interactions can begin,trust may need to be established between two interactive entities in which an entity may ask the other to provide some information involving privacy.Con...In network environments,before meaningful interactions can begin,trust may need to be established between two interactive entities in which an entity may ask the other to provide some information involving privacy.Consequently,privacy protection and trust establishment become important in network interactions.In order to protect privacy while facilitating effective interactions,we propose a trust-based privacy protection method.Our main contributions in this paper are as follows:(1)We introduce a novel concept of k-sensitive privacy as a measure to assess the potential threat of inferring privacy;(2)According to trust and k-sensitive privacy evaluation,our proposed method can choose appropriate interaction patterns with lower degree of inferring privacy threat;(3)By considering interaction patterns for privacy protection,our proposed method can overcome the shortcomings of some current privacy protection methods which may result in low interaction success rate.Simulation results show that our method can achieve effective interactions with less privacy loss.展开更多
By launching a currency war against China, the U.S. aims to prompt a diversion in global wealth allocation. With RMB in the center of the global currency war, Chinas economy is dancing on the rope in striving to strik...By launching a currency war against China, the U.S. aims to prompt a diversion in global wealth allocation. With RMB in the center of the global currency war, Chinas economy is dancing on the rope in striving to strike an internal and external balance. If China＇s monetary policy is ＂kidnapped＂ by America, the consequences will be unimaginably disastrous. Low interest rate in the longrun will probably result in the same bubble economy as Japan had after the Plaza Accord, which can even be stabbed, Thus, it is necessary to have a systematic long-term strategy as to how to look after both partial and overall interests.展开更多
As an impact of International Financial Crisis,the Greek sovereign debt crisis suddenly turned up.Some European countries'debt crisis got further unveiled.The mounting risk of world sovereign crisis could be the p...As an impact of International Financial Crisis,the Greek sovereign debt crisis suddenly turned up.Some European countries'debt crisis got further unveiled.The mounting risk of world sovereign crisis could be the principal risk of world economy and financial market after the international financial crisis and would threaten the global economy recovery.The world economy,unchained from the international financial crisis,might enter the next phase of sovereign debt crisis.展开更多
With the rapid development of China's modern cities,the scale of urban construction land has experienced dramatic changes.The forecast of urban construction land is the important content of urban construction deve...With the rapid development of China's modern cities,the scale of urban construction land has experienced dramatic changes.The forecast of urban construction land is the important content of urban construction development,and guarantee for healthy,rapid and intensive development of cities,therefore,we must reasonably determine the scale of urban construction land.Based on the status quo of construction land in Chongqing Municipality during the period 2000-2009,this article selects GM(1,1) model,linear model and non-linear model,to forecast the scale of construction land and each type of land subordinate to it in Chongqing Municipality during the period 2010-2014,respectively.The results show that the construction land in Chongqing Municipality will increase substantially during the period 2010-2014,and the area of each type of land subordinate to construction land will also increase to varying degrees,therefore the land contradictions will become more prominent.展开更多
In the process of transformation and upgrading of China's economy from high-speed growth to high-quality development,finance serves as the"booster"and"absorbant,"which provides necessary capita...In the process of transformation and upgrading of China's economy from high-speed growth to high-quality development,finance serves as the"booster"and"absorbant,"which provides necessary capital for economic restructuring,transformation,and upgrading.It further allows old-fashioned,excess,and invalid production capacity to be phased out in a market-oriented approach to prevent and control risks.To make the best of finance means,China has enhanced the pertinence and effectiveness of financing in serving the real economy,so as to realize mutual support,symbiosis,and shared prosperity of finance and the real economy.展开更多
Against the background of an unfavorable external environment,China’s foreign trade ran smoothly in 2019.The Chinese government has rolled out a raft of policies and measures to stabilize foreign trade.Meanwhile,new ...Against the background of an unfavorable external environment,China’s foreign trade ran smoothly in 2019.The Chinese government has rolled out a raft of policies and measures to stabilize foreign trade.Meanwhile,new modes of trade such as cross-border e-commerce and market procurement trade have flourished,which helped the entry of more foreign products into China.For instance,at the first China International Import Expo(CIIE)in 2018,88 e-commerce enterprises had in-depth cooperation with more than 400 international brands in more than 30 countries.A slew of overseas brands chose Alibaba,JD,Suning and other cross-border e-commerce platforms as their“standard”channels to enter China.At the second CIIE in 2019,JD,an e-commerce giant,announced that it would purchase RMB 400 billion of imported goods in the next three years.展开更多
China has implemented a strict quarantine policy and launched a full-scale campaign to prevent and contain COVID-19 since its outbreak.China's economy had thus paid a heavy price from January to February,seeing th...China has implemented a strict quarantine policy and launched a full-scale campaign to prevent and contain COVID-19 since its outbreak.China's economy had thus paid a heavy price from January to February,seeing the most serious economic decline over the past four decades.As the country effectively brings the epidemic under control,China's economy has started to gradually recover as a whole.The significant recovery of industrial production and investment along with other upbeat economic data in March show that China's economy is gradually returning to the normal.展开更多
基金funded by the Open Foundation of Key Laboratory of Cyberspace Security,Ministry of Education[KLCS20240210].
文摘With the rapid growth of the Internet and social media, information is widely disseminated in multimodal forms, such as text and images, where discriminatory content can manifest in various ways. Discrimination detection techniques for multilingual and multimodal data can identify potential discriminatory behavior and help foster a more equitable and inclusive cyberspace. However, existing methods often struggle in complex contexts and multilingual environments. To address these challenges, this paper proposes an innovative detection method, using image and multilingual text encoders to separately extract features from different modalities. It continuously updates a historical feature memory bank, aggregates the Top-K most similar samples, and utilizes a Gated Recurrent Unit (GRU) to integrate current and historical features, generating enhanced feature representations with stronger semantic expressiveness to improve the model’s ability to capture discriminatory signals. Experimental results demonstrate that the proposed method exhibits superior discriminative power and detection accuracy in multilingual and multimodal contexts, offering a reliable and effective solution for identifying discriminatory content.
基金We thank National Key R&D Program of China(2016YFA0602601),National Natural Science Foundation of China(71573062),China Energy Modeling Forum(CEMF),for support of the study.
文摘A quantitative model was applied to analyze the energy demand and CO2 emissions in China following the Energy Production and Consumption Revolution Strategy(2016e2030)and long-term economic and social development target China Dream.Results showed that 1)toward the 2050 China Dream target,total final energy consumption is expected to peak at 3.9 Gtce in 2030 and remain stable until 2050,whereas total primary energy consumption is expected to reach an upper platform by 2040 and around 5.8 Gtce by 2050;2)the proportion of non-fossil fuels is expected to reach approximately 50%and that of natural gas to reach more than 16%by 2050;3)CO2 emissions from energy use are expected to peak at 9.6 Gt by no later than 2030 and then gradually decline to 6.7 Gt by 2050.
基金the National Natural Science Foundation of China (60673054, 60773129)theExcellent Youth Science and Technology Foundation of Anhui Province of China.
文摘Geographic location of nodes is very useful in a sensor network. Previous localization algorithms assume that there exist some anchor nodes in this kind of network, and then other nodes are estimated to create their coordinates. Once there are not anchors to be deployed, those localization algorithms will be invalidated. Many papers in this field focus on anchor-based solutions. The use of anchors introduces many limitations, since anchors require external equipments such as global position system, cause additional power consumption. A novel positioning algorithm is proposed to use a virtual coordinate system based on a new concept--virtual anchor. It is executed in a distributed fashion according to the connectivity of a node and the measured distances to its neighbors. Both the adjacent member information and the ranging distance result are combined to generate the estimated position of a network, one of which is independently adopted for localization previously. At the position refinement stage the intermediate estimation of a node begins to be evaluated on its reliability for position mutation; thus the positioning optimization process of the whole network is avoided falling into a local optimal solution. Simulation results prove that the algorithm can resolve the distributed localization problem for anchor-free sensor networks, and is superior to previous methods in terms of its positioning capability under a variety of circumstances.
基金Under the auspices of Science and Technology Service Network Initiative of the Chinese Academy of Sciences(No.KEJ-EW-ZY-004)
文摘Resources and environment carrying capacity is central to not only regional sustainable development but also major function-oriented zoning. This paper presents an evaluation index system for resources and environment carrying capacity based on four aspects of carrying capacity(i.e., water resources, land resources, the environment, and ecosystems) by using a square deviation decision-making method, and on the basis of above effort evaluates the resources and environment carrying capacity across 31 provincial regions in China(not including Hong Kong, Macao and Taiwan regions of China). In addition, this paper evaluates the current state of socio-economic development, and analyzes the spatial distribution of resources and environment pressure. The results showed that distinct spatial differences in resources and environment carrying capacity and pressure across provincial regions. Resources and environment pressure is affected by both comprehensive resources and environment carrying capacity and socio-economic development. Regions subjected to lower degrees of resources and environment pressure will be restricted by resources and environmental problems through future courses of development owing to excessively low carrying capacities. By contrast, regions with higher comprehensive resources and environment carrying capacity will be subjected to excessively high levels of resources and environment pressure because of rapid socio-economic development. Both of resources and environment carrying capacity and pressure must therefore be considered in the allocation of country-binding targets to provincial regions.
基金Project (Nos. 90412012 and 60673160) supported by the NationalNatural Science Foundation of China
文摘Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies.
文摘The paper summarizes results of the China Energy Modeling Forum's(CEMF)first study.Carbon emissions peaking scenarios,consistent with China's Paris commitment,have been simulated with seven national and industry-level energy models and compared.The CO2 emission trends in the considered scenarios peak from 2015 to 2030 at the level of 9e11 Gt.Sector-level analysis suggests that total emissions pathways before 2030 will be determined mainly by dynamics of emissions in the electric power industry and transportation sector.Both sectors will experience significant increase in demand,but have low-carbon alternative options for development.Based on a side-by-side comparison of modeling input and results,conclusions have been drawn regarding the sources of emissions projections differences,which include data,views on economic perspectives,or models'structure and theoretical framework.Some suggestions have been made regarding energy models'development priorities for further research.
基金supported by the National Basic Research Program of China(No.2012CB955700 and 2010CB955501)
文摘Based on the survey of international emissions trading system （ETS） and quantitative analysis, policy suggestions on establishing a carbon ETS in China are presented in this study. Sectors sensitive to carbon prices, e.g., the power generation sector and the iron and steel industry, are given priority to be covered by the ETS. Interregional carbon trading should be carried out as early as possible. The cap of the ETS should be based on China＇s carbon intensity reduction target with the floor carbon price for the market being set in the beginning. Suggestions on the infrastructure of ETS are also proposed, including the national wide carbon measuring, reporting, verification system building. account registration system and the legislation to national
基金s This work was supported by the National Key Technology Research and Development Program of the Ministry of Science and Technology (2016YFA0602601), Science and Technology Project of the State Grid Corporation of China Headquarters ''Research and Development of China Multi-regional Compre hensive Analysis and Forecast Mcxlel System for Energy Sup ply and Demand Fourth National Climate Assessment Report: Mitigation of Climate Change’’, and National Natural Science Foundation of China Program (71573145, 71573062).
文摘This study focuses on a national regional coordinated development strategy and adopts China Multi-Regional Computable General Equilibrium model to analyze the economic and social development, energy demand, and carbon emissions of the provinces during the 14th Five-Year Plan (FYP, 2021 2025) period based on the economic development and energy demand since the New Normal. The main conclusions are the following: 1) Under the guidance of the regional coordinated development strategy, 13 provinces/municipalities are expected to have a per capita gross domestic product (GDP) of more than US$15,000, and 16 provinces/municipalities will have a per capita GDP of US$10,000 15,000. All provincial economies are expected to achieve steady and rapid development by the end of the 14th FYP. 2) The total energy consumption of the provinces is expected to reach 5.45 Gtce (excluding Tibet) in 2025, and the average annual growth rate is approximately 1.5%. The growth of energy demand will remain in low speed. The key point of energy demand will gradually shift from the eastern to the middle area, while the proportion of energy use in the western provinces will remain stable, which is consistent with the economic development stage and regional coordinated development strategy. 3) The annual average carbon intensity (mainly considering carbon emissions from energy use) of the provinces will approximately with most provinces dropping by over 4.0%. The trend of a considerable decline in carbon intensity, as observed in recent years, is expected to continue.
文摘To avoid the curse of dimensionality, text categorization （TC） algorithms based on machine learning （ML） have to use an feature selection （FS） method to reduce the dimensionality of feature space. Although having been widely used, FS process will generally cause information losing and then have much side-effect on the whole performance of TC algorithms. On the basis of the sparsity characteristic of text vectors, a new TC algorithm based on lazy feature selection （LFS） is presented. As a new type of embedded feature selection approach, the LFS method can greatly reduce the dimension of features without any information losing, which can improve both efficiency and performance of algorithms greatly. The experiments show the new algorithm can simultaneously achieve much higher both performance and efficiency than some of other classical TC algorithms.
文摘This paper examines the impact of climate change on China＇s grain production and food security. The research is one of the four studies on future conditions of China＇s food production system under the influence of climate change using numerical simulation methods, carried out under a national 973 project entitled ＂impacts of climate change on food systems in China and its adaptation＂. The other three studies focus on changes in cultivated land area and food production, while this study incorporates their grain yield results into a general equilibrium model to simulate future conditions of the grain market. Our simulation analysis arrives at the impact of climate change by comparing such economic variables as grain production, consumption, and GDP growth rate between a baseline scenario and two climate change scenarios. Our results are summarized as follows： （1） In 2050, the total grain production will reach 689.683 million tons--584.264 million tons of total grain consumption and 42.808 million tons of exports. Without considering losses and inventory demand, in 2050 China＇s grain supply and demand will remain well balanced, with a slight surplus expected. （2） Climate change is expected to benefit China＇s macro economy and individual sectors. In comparison with the baseline scenario of no climate change, real wage, real GDP, investment, household consumption, exports, and other macroeconomic indicators will rise under the climate change scenarios. As far as the agricultural, manufacturing, and service sectors are concerned, production, consumption, imports, and exports will each be favorably affected by climate change. （3） The favorable impact of climate change on China＇s macroeconomy and individual sectors under the high emissions scenario （A2） is stronger than that under the low emissions scenario （B2）. （4） In the grain market, climate change is expected to increase supply, reduce imports, increase supply, and demand; and supply will increase more than demand does. All in all, if taking into the fertilization effect of CO2 account, climate change is expected to strengthen China＇s grain supply and safeguard food security.
基金Supported by the National Natural Science Foundation of China(Nos 71103179,71102129,10835005)Program for Young Innovative Research Team in China University of Political Science and Law,2010 Fund Project under the Ministry of Education of China for youth(10YJC630425)Generalized Virtual Economy Fund(GX2011-1019(Y)).
文摘The purpose of this work is to study the principle fluctuation modes of the global stock market,which is regarded as a complex system.It is proposed that the systematic risk can be reflected by the trace calculated from the cross-correlation matrix,and the integrity can be classified into clusters according to the plus-minus signs of the elements of the eigenvectors corresponding to several top largest eigenvalues whose total value accounts for more than 60 percent of the trace.The principle fluctuation modes of 30 stock markets are in the same direction in each year of 2005-2010.According to the classification criteria proposed here,the stock markets of the Americas,Europe and Asia & Oceania are automatically classified into different clusters,while Brazil,Russia and China are separated.
基金research funding from the Beijing Education Commission under Grant No. KM201010005027National Natural Science Foundation of China under Grant No. 61074128National Social Science Foundation of China under Grant No. 07CTQ010
文摘In network environments,before meaningful interactions can begin,trust may need to be established between two interactive entities in which an entity may ask the other to provide some information involving privacy.Consequently,privacy protection and trust establishment become important in network interactions.In order to protect privacy while facilitating effective interactions,we propose a trust-based privacy protection method.Our main contributions in this paper are as follows:(1)We introduce a novel concept of k-sensitive privacy as a measure to assess the potential threat of inferring privacy;(2)According to trust and k-sensitive privacy evaluation,our proposed method can choose appropriate interaction patterns with lower degree of inferring privacy threat;(3)By considering interaction patterns for privacy protection,our proposed method can overcome the shortcomings of some current privacy protection methods which may result in low interaction success rate.Simulation results show that our method can achieve effective interactions with less privacy loss.
文摘By launching a currency war against China, the U.S. aims to prompt a diversion in global wealth allocation. With RMB in the center of the global currency war, Chinas economy is dancing on the rope in striving to strike an internal and external balance. If China＇s monetary policy is ＂kidnapped＂ by America, the consequences will be unimaginably disastrous. Low interest rate in the longrun will probably result in the same bubble economy as Japan had after the Plaza Accord, which can even be stabbed, Thus, it is necessary to have a systematic long-term strategy as to how to look after both partial and overall interests.
文摘As an impact of International Financial Crisis,the Greek sovereign debt crisis suddenly turned up.Some European countries'debt crisis got further unveiled.The mounting risk of world sovereign crisis could be the principal risk of world economy and financial market after the international financial crisis and would threaten the global economy recovery.The world economy,unchained from the international financial crisis,might enter the next phase of sovereign debt crisis.
文摘With the rapid development of China's modern cities,the scale of urban construction land has experienced dramatic changes.The forecast of urban construction land is the important content of urban construction development,and guarantee for healthy,rapid and intensive development of cities,therefore,we must reasonably determine the scale of urban construction land.Based on the status quo of construction land in Chongqing Municipality during the period 2000-2009,this article selects GM(1,1) model,linear model and non-linear model,to forecast the scale of construction land and each type of land subordinate to it in Chongqing Municipality during the period 2010-2014,respectively.The results show that the construction land in Chongqing Municipality will increase substantially during the period 2010-2014,and the area of each type of land subordinate to construction land will also increase to varying degrees,therefore the land contradictions will become more prominent.
文摘In the process of transformation and upgrading of China's economy from high-speed growth to high-quality development,finance serves as the"booster"and"absorbant,"which provides necessary capital for economic restructuring,transformation,and upgrading.It further allows old-fashioned,excess,and invalid production capacity to be phased out in a market-oriented approach to prevent and control risks.To make the best of finance means,China has enhanced the pertinence and effectiveness of financing in serving the real economy,so as to realize mutual support,symbiosis,and shared prosperity of finance and the real economy.
文摘Against the background of an unfavorable external environment,China’s foreign trade ran smoothly in 2019.The Chinese government has rolled out a raft of policies and measures to stabilize foreign trade.Meanwhile,new modes of trade such as cross-border e-commerce and market procurement trade have flourished,which helped the entry of more foreign products into China.For instance,at the first China International Import Expo(CIIE)in 2018,88 e-commerce enterprises had in-depth cooperation with more than 400 international brands in more than 30 countries.A slew of overseas brands chose Alibaba,JD,Suning and other cross-border e-commerce platforms as their“standard”channels to enter China.At the second CIIE in 2019,JD,an e-commerce giant,announced that it would purchase RMB 400 billion of imported goods in the next three years.
文摘China has implemented a strict quarantine policy and launched a full-scale campaign to prevent and contain COVID-19 since its outbreak.China's economy had thus paid a heavy price from January to February,seeing the most serious economic decline over the past four decades.As the country effectively brings the epidemic under control,China's economy has started to gradually recover as a whole.The significant recovery of industrial production and investment along with other upbeat economic data in March show that China's economy is gradually returning to the normal.
