Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS sche...Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS scheme, which belongs to the Pulse Position Modulation （PPM）. The duty cycle of the PDS scheme is small, so it can economize the power for communication. By use of different patterns for code division and different frequencies for channel division, the communication system is capable of mitigating the inter-symbol interference （ISI） caused by the muhipath channel. The data rate of communication is 1000 bits/s at 8 kHz bandwidth. The receiver separates the channels by means of bandpass filters, and performs decoding by 4 copy-correlators to estimate the time delay shift value. Based on the theoretical analysis and numerical simulations, the PDS scheme is shown to be a robust and effective approach for underwater acoustic communication.展开更多
Pattern Time Delay Shift Coding (PDS) scheme is robust for underwater acoustic communication. The digital information are encoded in the time delay shift values of the Pattern, so the PDS scheme belongs to the Pulse P...Pattern Time Delay Shift Coding (PDS) scheme is robust for underwater acoustic communication. The digital information are encoded in the time delay shift values of the Pattern, so the PDS scheme belongs to the Pulse Position Modulation (PPM). Several Patterns are selected for code division that the communication system could have a high ability to mitigate the inter-symbol interference (ISI) caused by multipath channel. Four communication channels work on the same time divided by different frequency, which lead to 1000bits/s of the data rate of communication. The simulation experiments show that the PDS system could adapt to many underwater acoustic channels for high data rate and high reliability.展开更多
Desktop calibration of automatic transmission(AT) is a method which can reduce cost, enhance efficiency and shorten the development periods of a vehicle effectively. We primary introduced the principle and approach of...Desktop calibration of automatic transmission(AT) is a method which can reduce cost, enhance efficiency and shorten the development periods of a vehicle effectively. We primary introduced the principle and approach of desktop calibration of AT based on the condition of coupling characteristics between engine and torque converter and obtained right point exactly. It is shown to agree with experimental measurements reasonably well. It was used in different applications abroad based on AT technology and achieved a good performance of the vehicle compared with traditional AT technology which primary focuses on the drivability, performance and fuel consumption.展开更多
With the continued shrinking of the critical dimensions(CDs)of wafer patterning,the requirements for modeling precision in optical proximity correction(OPC)increase accordingly.This requirement extends beyond CD contr...With the continued shrinking of the critical dimensions(CDs)of wafer patterning,the requirements for modeling precision in optical proximity correction(OPC)increase accordingly.This requirement extends beyond CD controlling accuracy to include pattern alignment accuracy because misalignment can lead to considerable overlay and metal-via coverage issues at advanced nodes,affecting process window and yield.This paper proposes an efficient OPC modeling approach that prioritizes pattern-shift-related elements to tackle the issue accurately.Our method integrates careful measurement selection,the implementation of pattern-shift-aware structures in design,and the manipulation of the cost function during model tuning to establish a robust model.Confirmatory experiments are performed on a via layer fabricated using a negative tone development.Results demonstrate that pattern shifts can be constrained within a range of+1 nm,remarkably better than the original range of±3 nm.Furthermore,simulations reveal notable differences between post OPC and original masks when considering pattern shifts at locations sensitive to this phenomenon.Experimental validation confirms the accuracy of the proposed modeling approach,and a firm consistency is observed between the simulation results and experimental data obtained from actual design structures.展开更多
In order to meet the demands of underwater acoustic communication in under ice environment,a differential Pattern time delay shift coding underwater acoustic communication method based on parametric array is introduce...In order to meet the demands of underwater acoustic communication in under ice environment,a differential Pattern time delay shift coding underwater acoustic communication method based on parametric array is introduced in this paper.The under ice underwater acoustic channel is characterized by heavy multipath transmission.Under this model,a parametric array emission method of Pattern signal is derived and the system performance is analyzed.A broadband low frequency sound waves with narrow beam-pattern,which will reduce the interface reflections and suppress the effects of multipath transmission,can be obtained by the emission method.The Songhua River under ice trial results show that there is an anti-multipath property and a higher data rate in the under-ice acoustic channel in proposed approach.展开更多
The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS...The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS is to improve the quality of communication in shallow water. The open water experiments shoe that at the condition of 2 kHz bandwidth, the communication rate is more than 300 bit/s and error rate is at the level of 10-4. The details of PDS technique will be shown, including: principle of PDS coding, the model of Anti-multipath illterference and open water experimenis展开更多
Agricultural land use(ALU)critically influences food production and water resource allocation.This study examines the dynamics of ALU in the North China Plain(NCP),a region characterized by intensive agri-culture and ...Agricultural land use(ALU)critically influences food production and water resource allocation.This study examines the dynamics of ALU in the North China Plain(NCP),a region characterized by intensive agri-culture and severe groundwater over-exploitation,focusing on the multidimensional drivers and their implications for water resource management.By employing an elaborate classification scheme based on satellite imagery and extensive first-hand field data,we identified significant shifts in crop patterns.From 2013 to 2017,there was a notable transition from double crops(primarily wheat-maize)to single crops(primarily maize),covering 4600 km^(2)and accounting for 42%of single crops in 2013.From 2017 to 2022,there was a shift from single crops to economic forests,encompassing 3600 km^(2)and 22%of eco-nomic forests in 2017,including orchards,timber trees,and shelter forest belts.These shifts resulted in an 11%decrease in grain acreage(6800 km^(2))but an 11%increase in crop water consumption(6.3 km^(3))during 2013-2022.Notably,water consumption by economic forests increased by 126%(9.4 km^(3))during this period.This study highlights the critical need to balance competing demands for food and water security,providing valuable insights applicable to other agriculturally intensive regions worldwide.展开更多
文摘Underwater acoustic communication based on Pattern Tune Delay Shift Coding （PDS） communication scheme is studied. The time delay shift values of the pattern are used to encode the digital information in the PDS scheme, which belongs to the Pulse Position Modulation （PPM）. The duty cycle of the PDS scheme is small, so it can economize the power for communication. By use of different patterns for code division and different frequencies for channel division, the communication system is capable of mitigating the inter-symbol interference （ISI） caused by the muhipath channel. The data rate of communication is 1000 bits/s at 8 kHz bandwidth. The receiver separates the channels by means of bandpass filters, and performs decoding by 4 copy-correlators to estimate the time delay shift value. Based on the theoretical analysis and numerical simulations, the PDS scheme is shown to be a robust and effective approach for underwater acoustic communication.
文摘Pattern Time Delay Shift Coding (PDS) scheme is robust for underwater acoustic communication. The digital information are encoded in the time delay shift values of the Pattern, so the PDS scheme belongs to the Pulse Position Modulation (PPM). Several Patterns are selected for code division that the communication system could have a high ability to mitigate the inter-symbol interference (ISI) caused by multipath channel. Four communication channels work on the same time divided by different frequency, which lead to 1000bits/s of the data rate of communication. The simulation experiments show that the PDS system could adapt to many underwater acoustic channels for high data rate and high reliability.
文摘Desktop calibration of automatic transmission(AT) is a method which can reduce cost, enhance efficiency and shorten the development periods of a vehicle effectively. We primary introduced the principle and approach of desktop calibration of AT based on the condition of coupling characteristics between engine and torque converter and obtained right point exactly. It is shown to agree with experimental measurements reasonably well. It was used in different applications abroad based on AT technology and achieved a good performance of the vehicle compared with traditional AT technology which primary focuses on the drivability, performance and fuel consumption.
基金funded by the National Natural Science Foundation of China(Grant Nos.52130504,52305577,and 52205592)the Key Research and Development Plan of Hubei Province,China(Grant No.2022BAA013)+2 种基金the Major Program(JD)of Hubei Province,China(Grant No.2023BAA008-2)the Innovation Projection of Optics Valley Laboratory,China(Grant No.OVL2023PY003)the Postdoctoral Fellowship Program(Grade B)of the China Postdoctoral Science Foundation(Grant No.GZB20230244).
文摘With the continued shrinking of the critical dimensions(CDs)of wafer patterning,the requirements for modeling precision in optical proximity correction(OPC)increase accordingly.This requirement extends beyond CD controlling accuracy to include pattern alignment accuracy because misalignment can lead to considerable overlay and metal-via coverage issues at advanced nodes,affecting process window and yield.This paper proposes an efficient OPC modeling approach that prioritizes pattern-shift-related elements to tackle the issue accurately.Our method integrates careful measurement selection,the implementation of pattern-shift-aware structures in design,and the manipulation of the cost function during model tuning to establish a robust model.Confirmatory experiments are performed on a via layer fabricated using a negative tone development.Results demonstrate that pattern shifts can be constrained within a range of+1 nm,remarkably better than the original range of±3 nm.Furthermore,simulations reveal notable differences between post OPC and original masks when considering pattern shifts at locations sensitive to this phenomenon.Experimental validation confirms the accuracy of the proposed modeling approach,and a firm consistency is observed between the simulation results and experimental data obtained from actual design structures.
基金supported by the National Natural Science Foundation of China(61471137,61631008)Fok Ying Tung Education Foundation(151007)the 13th Five-Year Plan Communication Information Control and Security Technology Key Laboratory Foundation(61421060301162106001)
文摘In order to meet the demands of underwater acoustic communication in under ice environment,a differential Pattern time delay shift coding underwater acoustic communication method based on parametric array is introduced in this paper.The under ice underwater acoustic channel is characterized by heavy multipath transmission.Under this model,a parametric array emission method of Pattern signal is derived and the system performance is analyzed.A broadband low frequency sound waves with narrow beam-pattern,which will reduce the interface reflections and suppress the effects of multipath transmission,can be obtained by the emission method.The Songhua River under ice trial results show that there is an anti-multipath property and a higher data rate in the under-ice acoustic channel in proposed approach.
文摘The high rate digital acoustic communication technique for horizontal channels has been studied in this article. It is called as 'Pattern Time Delay Shift Coding (PDS) communication system.' The aim of the PDS is to improve the quality of communication in shallow water. The open water experiments shoe that at the condition of 2 kHz bandwidth, the communication rate is more than 300 bit/s and error rate is at the level of 10-4. The details of PDS technique will be shown, including: principle of PDS coding, the model of Anti-multipath illterference and open water experimenis
基金supported by the National Key Research and Development Program of China(2021YFB3900604)National Natural Science Foundation of China(52079065,52325901,and 42471399)World Bank China Programmatic Research on Water.
文摘Agricultural land use(ALU)critically influences food production and water resource allocation.This study examines the dynamics of ALU in the North China Plain(NCP),a region characterized by intensive agri-culture and severe groundwater over-exploitation,focusing on the multidimensional drivers and their implications for water resource management.By employing an elaborate classification scheme based on satellite imagery and extensive first-hand field data,we identified significant shifts in crop patterns.From 2013 to 2017,there was a notable transition from double crops(primarily wheat-maize)to single crops(primarily maize),covering 4600 km^(2)and accounting for 42%of single crops in 2013.From 2017 to 2022,there was a shift from single crops to economic forests,encompassing 3600 km^(2)and 22%of eco-nomic forests in 2017,including orchards,timber trees,and shelter forest belts.These shifts resulted in an 11%decrease in grain acreage(6800 km^(2))but an 11%increase in crop water consumption(6.3 km^(3))during 2013-2022.Notably,water consumption by economic forests increased by 126%(9.4 km^(3))during this period.This study highlights the critical need to balance competing demands for food and water security,providing valuable insights applicable to other agriculturally intensive regions worldwide.
