Chromium,a strategic mineral resource in China,is widely used in high-precision equipment manufacturing.As the world's leading consumer and importer of chromite,China's external dependence exceeds 99%.The sign...Chromium,a strategic mineral resource in China,is widely used in high-precision equipment manufacturing.As the world's leading consumer and importer of chromite,China's external dependence exceeds 99%.The significant imbalance between domestic supply and demand seriously threatens national economic security.This study discusses the state of China's chromium resource supply from four aspects:the overview of domestic and global chromium resources,China's chromite production and import volume,the sources of imported chromite,and risk analysis.Considering the chromium industrial chain and factors such as production,consumption,and recovery tendency of chromium-bearing stainless steel,it is forecasted that China's demand for chromium ore will decline by 2040.This could considerably reduce the security situation of chromium resources.This study proposes five strategies for securing chromium resources:technological innovation,enhancing international cooperation and acquiring overseas resources,constructing a new pattern of“dual circulation”resource guarantee for sea-land transportation,encouraging chromium recycling,and building an emergency management system and strategic reserve mechanism for chromium resources.展开更多
Predicting tourism traffic demand accurately plays an important role in making effective policies for tourist administration. It helps to distribute the resources reasonably and avoid the tourism congestions. This pap...Predicting tourism traffic demand accurately plays an important role in making effective policies for tourist administration. It helps to distribute the resources reasonably and avoid the tourism congestions. This paper considered the noise interference and proposed a hybrid model, combining ensemble empirical mode decomposition (EEMD), deep belief network (DBN) and Google trends, for tourism traffic demand prediction. This model firstly applied dislocation weighted synthesis method to combine Google trends into a search composite index, and then it denoised the series with EEMD. EEMD extracted the high frequency noise from the original series. The low frequency series of search composite index would be used to forecast the low frequency tourism traffic series. Taking the inbound tourism in Shanghai as an example, this paper trained the model and predicted the next 12 months tourism arrivals. The conclusion demonstrated that the forecast error of EEMD-DBN model is lower remarkably than the baselines of ARIMA, GM(1,1), FTS, SVM, CES and DBN model. This revealed that nosing processing is necessary and EEMD-DBN forecast model can improve the prediction accuracy.展开更多
In China, the proven reserves of natural gas is 3.86 trillion cubic meters (tcm). This figure will quite possibly increase at a high speed in the future. At present, the annual production of natural gas has exceeded 3...In China, the proven reserves of natural gas is 3.86 trillion cubic meters (tcm). This figure will quite possibly increase at a high speed in the future. At present, the annual production of natural gas has exceeded 34 billion cubic meters (bcm), which, likewise, will rise sharply. The pipeline construction has basically taken shape, which will be gradually perfected. And the gas consumption market is in the startup stage, which will be rapidly expanded in the quite near future.展开更多
基金supported by the Consulting Research Project of the Chinese Academy of Engineering (Nos.2022-XY-82,2023-XY-21,and 2023-XZ-25).
文摘Chromium,a strategic mineral resource in China,is widely used in high-precision equipment manufacturing.As the world's leading consumer and importer of chromite,China's external dependence exceeds 99%.The significant imbalance between domestic supply and demand seriously threatens national economic security.This study discusses the state of China's chromium resource supply from four aspects:the overview of domestic and global chromium resources,China's chromite production and import volume,the sources of imported chromite,and risk analysis.Considering the chromium industrial chain and factors such as production,consumption,and recovery tendency of chromium-bearing stainless steel,it is forecasted that China's demand for chromium ore will decline by 2040.This could considerably reduce the security situation of chromium resources.This study proposes five strategies for securing chromium resources:technological innovation,enhancing international cooperation and acquiring overseas resources,constructing a new pattern of“dual circulation”resource guarantee for sea-land transportation,encouraging chromium recycling,and building an emergency management system and strategic reserve mechanism for chromium resources.
文摘Predicting tourism traffic demand accurately plays an important role in making effective policies for tourist administration. It helps to distribute the resources reasonably and avoid the tourism congestions. This paper considered the noise interference and proposed a hybrid model, combining ensemble empirical mode decomposition (EEMD), deep belief network (DBN) and Google trends, for tourism traffic demand prediction. This model firstly applied dislocation weighted synthesis method to combine Google trends into a search composite index, and then it denoised the series with EEMD. EEMD extracted the high frequency noise from the original series. The low frequency series of search composite index would be used to forecast the low frequency tourism traffic series. Taking the inbound tourism in Shanghai as an example, this paper trained the model and predicted the next 12 months tourism arrivals. The conclusion demonstrated that the forecast error of EEMD-DBN model is lower remarkably than the baselines of ARIMA, GM(1,1), FTS, SVM, CES and DBN model. This revealed that nosing processing is necessary and EEMD-DBN forecast model can improve the prediction accuracy.
文摘In China, the proven reserves of natural gas is 3.86 trillion cubic meters (tcm). This figure will quite possibly increase at a high speed in the future. At present, the annual production of natural gas has exceeded 34 billion cubic meters (bcm), which, likewise, will rise sharply. The pipeline construction has basically taken shape, which will be gradually perfected. And the gas consumption market is in the startup stage, which will be rapidly expanded in the quite near future.
