Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular...Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular LDPC codes with Unequal Error Protection (UEP)property is designed in this letter. Simulation results show that the transmission quality of the image may be effectively improved with this class of irregular LDPC code.展开更多
This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medi...This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medium voltage switchgear of a nuclear power plant. This consideration is important for both measurement and protection functions of the digital protective relays. This is a study to ascertain the best options for a suitable solution to prevent CT saturation in relations to its protective capabilities during short circuit fault without compromising the CT accuracy class during normal operation of the system, while ensuring its conformity to the design requirement is within limit. The advantages of current transformers have proven not only to be reliable and safe, but also are of easy handling, reduction of the cost and components on the MV （medium voltage） switchgear. The purpose of this research is to identify best approach to resolve the existing problems in the current protection system. With the view of LPCT （low power current transformer） which has been newly constructed by few manufacturers to provide good protection and a wide range of measuring function without errors, some other solutions will be considered in this research.展开更多
Groundwater is the water located beneath the earth＇s surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environ...Groundwater is the water located beneath the earth＇s surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environment, public health, welfare, and long-term economic growth, which affects the daily activities of human beings. In modern urban areas, the primary contaminants of groundwater are artificial products, such as gasoline and diesel. To protect this important water resource, a series of efforts have been exerted, including enforcement and remedial actions. Each year, the TGPC （Texas Groundwater Protection Committee） in US publishes a ＂Joint Groundwater Monitoring and Contamination Report＂ to describe historic and new contamination cases in each county, which is an important data source for the design of prevention strategies. In this paper, a DDM （data dependent modeling） approach is proposed to predict county-level NCC （new contamination cases）. A case study with contamination information from Harris County in Texas was conducted to illustrate the modeling and prediction process with promising results. The one-step prediction error is 1.5%, while the two-step error is 12.1%. The established model can be used at the county-level, state-level, and even at the country-level. Besides, the prediction results could be a reference during decision-making processes.展开更多
This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global va...This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global value chain participation, Using the national panel data from 2000 to 2015, based on the error correction model and import-intensity- adjusted demand model, our results show that the slowdown of China＇s trade growth in 2012-2015 was mainly a result of cyclical factors. Using 2000-2015 industry- level data, we also find that the structure of trade goods had an inhibitory effect on the import slowdown but a positive effect on the export slowdown. Trade protectionism had an adverse effect on the trade growth slowdown. The global value chain participation marginally contributed to the slowdown in trade growth. Therefore, the impacts of structural factors on trade growth slowdown cannot be ignored, and related policies should receive greater attention from policy-makers.展开更多
文摘Based on the property that high degree variable nodes within an irregular LowDensity Parity-Check (LDPC) code have more powerful error-correcting capability than that of low degree variable nodes, a group of irregular LDPC codes with Unequal Error Protection (UEP)property is designed in this letter. Simulation results show that the transmission quality of the image may be effectively improved with this class of irregular LDPC code.
文摘This paper discusses a preferable solution to mitigate the CT （current transformer） saturation problem, and at same time, reduce the accuracy errors when considering the selection of CTs for installation on the medium voltage switchgear of a nuclear power plant. This consideration is important for both measurement and protection functions of the digital protective relays. This is a study to ascertain the best options for a suitable solution to prevent CT saturation in relations to its protective capabilities during short circuit fault without compromising the CT accuracy class during normal operation of the system, while ensuring its conformity to the design requirement is within limit. The advantages of current transformers have proven not only to be reliable and safe, but also are of easy handling, reduction of the cost and components on the MV （medium voltage） switchgear. The purpose of this research is to identify best approach to resolve the existing problems in the current protection system. With the view of LPCT （low power current transformer） which has been newly constructed by few manufacturers to provide good protection and a wide range of measuring function without errors, some other solutions will be considered in this research.
文摘Groundwater is the water located beneath the earth＇s surface in the soil pore spaces and in the fractures of rock formations. As one of the most important natural resources, groundwater is associated with the environment, public health, welfare, and long-term economic growth, which affects the daily activities of human beings. In modern urban areas, the primary contaminants of groundwater are artificial products, such as gasoline and diesel. To protect this important water resource, a series of efforts have been exerted, including enforcement and remedial actions. Each year, the TGPC （Texas Groundwater Protection Committee） in US publishes a ＂Joint Groundwater Monitoring and Contamination Report＂ to describe historic and new contamination cases in each county, which is an important data source for the design of prevention strategies. In this paper, a DDM （data dependent modeling） approach is proposed to predict county-level NCC （new contamination cases）. A case study with contamination information from Harris County in Texas was conducted to illustrate the modeling and prediction process with promising results. The one-step prediction error is 1.5%, while the two-step error is 12.1%. The established model can be used at the county-level, state-level, and even at the country-level. Besides, the prediction results could be a reference during decision-making processes.
文摘This paper analyzes whether the slowdown of China＇s trade in 2012-2015 was cyclical or structural, and further discusses the effects of structural factors, including trade structure, trade protectionism and global value chain participation, Using the national panel data from 2000 to 2015, based on the error correction model and import-intensity- adjusted demand model, our results show that the slowdown of China＇s trade growth in 2012-2015 was mainly a result of cyclical factors. Using 2000-2015 industry- level data, we also find that the structure of trade goods had an inhibitory effect on the import slowdown but a positive effect on the export slowdown. Trade protectionism had an adverse effect on the trade growth slowdown. The global value chain participation marginally contributed to the slowdown in trade growth. Therefore, the impacts of structural factors on trade growth slowdown cannot be ignored, and related policies should receive greater attention from policy-makers.
