To solve the hardware deployment problem caused by the vast demanding computational complexity of convolutional layers and limited hardware resources for the hardware network inference,a look-up table(LUT)-based convo...To solve the hardware deployment problem caused by the vast demanding computational complexity of convolutional layers and limited hardware resources for the hardware network inference,a look-up table(LUT)-based convolution architecture built on a field-programmable gate array using integer multipliers and addition trees is used.With the help of the Winograd algorithm,the optimization of convolution and multiplication is realized to reduce the computational complexity.The LUT-based operator is further optimized to construct a processing unit(PE).Simultaneously optimized storage streams improve memory access efficiency and solve bandwidth constraints.The data toggle rate is reduced to optimize power consumption.The experimental results show that the use of the Winograd algorithm to build basic processing units can significantly reduce the number of multipliers and achieve hardware deployment acceleration,while the time-division multiplexing of processing units improves resource utilization.Under this experimental condition,compared with the traditional convolution method,the architecture optimizes computing resources by 2.25 times and improves the peak throughput by 19.3 times.The LUT-based Winograd accelerator can effectively solve the deployment problem caused by limited hardware resources.展开更多
The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table （LUT）, which is usually created for a special remote sensor and cannot be applied to other sensors. For practica...The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table （LUT）, which is usually created for a special remote sensor and cannot be applied to other sensors. For practical application, a general purpose Rayleigh scattering LUT which can be applied to all ocean color remote sensors is generated. An adding-doubling method to solve the vector radiative transfer equation in the plane-parallel atmosphere is deduced in detail. Compared with the exact Rayleigh scattering radiance derived from the MODIS exact Rayleigh scattering LUT, it is proved that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.25%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore, the adding-doubling method can be used to generate the exact Rayleigh scattering LUT for the ocean color remote sensors. Finally, the general purpose exact Rayleigh scattering LUT is generated using the adding-doubling method. On the basis of the general purpose LUT, the calculated Rayleigh scattering radiance is tested by comparing with the LUTs ofMODIS, SeaWiFS and the other ocean color sensors, showing that the relative errors are all less than 0.5%, and this general purpose LUT can be applied to all ocean color remote sensors.展开更多
The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the acquisition.The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the t...The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the acquisition.The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking loop.Since the frequency step is usually 500 Hz or larger,the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking state.The straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the FFT.However,these solutions intensify the complexity and amount of computation.The contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm,which achieves fine acquisition by a look-up table.After coarse acquisition using the parallel frequency acquisition(PFA)algorithm,the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing load.When the Doppler shift is within the queryable range of the table,the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.展开更多
Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation （...Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation （DIC） algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss-Newton （IC-GN） algorithm. The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.展开更多
Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents...Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.展开更多
Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical a...Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.展开更多
Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up ...Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.展开更多
In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table （LUT） approach. Circuit simu- lation o...In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table （LUT） approach. Circuit simu- lation of newly designed devices in TCAD environment is a very slow and tedious process involving complex scripting. Hence, the LUT based modeling approach has been proposed as a faster and easier alternative in ca- dence environment. The LUTs are prepared by extracting data from the device characteristics obtained from device simulation in TCAD. A comparative study is shown between the TCAD simulation and the LUT-based alternative to showcase the accuracy of modeled devices. Finally the look-up table approach is used to evaluate the perform- ance of circuits implemented using 14 nm nMOSFET.展开更多
A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors.It is based on the principle that the counts in crystal position histogram obey the Gau...A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors.It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model(GMM).This method has taken full consideration of the characteristics of the GMM and the detector itself.The experimental results have proved that it is simple,reliable,and universal.展开更多
A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is studied,which is based on a look-up table algorithm.The algorithm uses parametri...A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is studied,which is based on a look-up table algorithm.The algorithm uses parametric method to represent aerosol extinction profiles and simulate different atmospheric aerosol states through atmospheric radiation transfer model.Based on the method,aerosol extinction profile was obtained during six cloud-free days.The O4 differential air mass factor(dAMF)measured by MAX-DOAS is compared with the corresponding model results under different atmospheric conditions(R^2=0.78).The aerosol optical thickness,aerosol weight factor in boundary layer,and the height of the boundary layer are obtained after the process of minimization and look-up table method.The retrieved aerosol extinction in boundary layer is compared with PM2.5 data measured by ground point instrument.The diurnal variation trends of the two methods are in good agreement.The correlation coefficients of the two methods are 0.71 when the aerosol optical thickness is smaller than 0.5.The results show that the look-up table method can obtain the aerosol state of the troposphere and provide validation for other instrument data.展开更多
Presently, there are mainly two problems that prevent Electric Vehicles (EVs) from becoming popular against the Internal Combustion Engine Vehicles (ICEVs), namely: short range and too long to recharge the battery pac...Presently, there are mainly two problems that prevent Electric Vehicles (EVs) from becoming popular against the Internal Combustion Engine Vehicles (ICEVs), namely: short range and too long to recharge the battery pack of the EV. Due to this, battery development is a crucial aspect to improve the performance of EVs. This progress requires dependable computer aided designs to model the characteristics of a battery accurately and reliably. This paper uses Power Systems Computer Aided Design (PSCAD) to create an equivalent runtime circuit model to observe the qualities of the Lithium Iron Phosphate battery cell under discharge at different temperatures. The model is a 3-R-C branch runtime equivalent circuit model. In order to find the fixed parameters of the circuit, MATLAB was used to implement basic current voltage characteristics. 3-D tables have been used in PSCAD to implement the State of Charge (SOC) and temperature dependent circuit parameters of the model. Once the simulations for all temperatures were completed, the average marginal error between measured and simulated terminal voltage came to be 2.1%, therefore making PSCAD an accurate simulation tool for modeling equivalent circuits of different batteries.展开更多
Laser triangulation theory was used to develop a novel contact-free method for measuring the coal level in a silo under harsh environmental conditions found in coal mines, such as the presence of dense dust, high humi...Laser triangulation theory was used to develop a novel contact-free method for measuring the coal level in a silo under harsh environmental conditions found in coal mines, such as the presence of dense dust, high humidity, and low illumination. A laser source and a camera were mounted at the top of the silo. The laser spot projected into the silo was imaged by the camera. The pinhole imaging principle allows the level to be found from the lateral shift of the spot image on the sensor. A pre-calibrated look-up table of the coal depth versus spot position was used to obtain the depth. The measurement accuracy depends on the step size used during pre-calibration. The actual application of a device designed according to these principles shows that it is easy to implement. The detection of the coal level in a silo at the low illumination level found in coal mines is demonstrated.展开更多
In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF li...In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.展开更多
An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the conv...An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA) was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base, on-chip fuzzification and defuzzification, faster response with speeds over giga fuzzy logic inferences per sec (FLIPS), and an inexpensive VLSI chip. The key application areas are: 1) on-chip integrated controllers;and 2) on-chip co-integration for entire system of sensors, circuits, controllers, and detectors for building complete instrument systems.展开更多
A real time mixing module for high definition television (HDTV) data of SMPTE 274M and PC video data is designed. The hardware implementation, algorithm and simulation of the mixing module are given. In order to impro...A real time mixing module for high definition television (HDTV) data of SMPTE 274M and PC video data is designed. The hardware implementation, algorithm and simulation of the mixing module are given. In order to improve the capability of data processing, an anti-fuse FPGA chip and a mechanism of pipelining and modularization are adopted. With 6 parallel LUTs and a fast algorithm, it can mix 4∶2∶2 component signals in luminance and chrominance space respectively in real time. According to the simulation, the module has the ability to mix the uncompressed HDTV data with PC video data in real time, which can not be fulfilled by current ASIC chips. Furthermore, it can be extended to multi-stage mixing with the thoughts implied by the design. The mixing module can be widely used in HDTV production systems.展开更多
基金The Academic Colleges and Universities Innovation Program 2.0(No.BP0719013)。
文摘To solve the hardware deployment problem caused by the vast demanding computational complexity of convolutional layers and limited hardware resources for the hardware network inference,a look-up table(LUT)-based convolution architecture built on a field-programmable gate array using integer multipliers and addition trees is used.With the help of the Winograd algorithm,the optimization of convolution and multiplication is realized to reduce the computational complexity.The LUT-based operator is further optimized to construct a processing unit(PE).Simultaneously optimized storage streams improve memory access efficiency and solve bandwidth constraints.The data toggle rate is reduced to optimize power consumption.The experimental results show that the use of the Winograd algorithm to build basic processing units can significantly reduce the number of multipliers and achieve hardware deployment acceleration,while the time-division multiplexing of processing units improves resource utilization.Under this experimental condition,compared with the traditional convolution method,the architecture optimizes computing resources by 2.25 times and improves the peak throughput by 19.3 times.The LUT-based Winograd accelerator can effectively solve the deployment problem caused by limited hardware resources.
基金supported by the National Natural Science Foundation of China under contract No.40506036the High Tech Research and Development"863"Program of China under contract No.2003AA131160-04the Science and Technology Plan of Zhejiang Province of China under contract Nos 2004E60054 and 2004C13027.
文摘The current exact Rayleigh scattering calculation of ocean color remote sensing uses the look-up table （LUT）, which is usually created for a special remote sensor and cannot be applied to other sensors. For practical application, a general purpose Rayleigh scattering LUT which can be applied to all ocean color remote sensors is generated. An adding-doubling method to solve the vector radiative transfer equation in the plane-parallel atmosphere is deduced in detail. Compared with the exact Rayleigh scattering radiance derived from the MODIS exact Rayleigh scattering LUT, it is proved that the relative error of Rayleigh scattering calculation with the adding-doubling method is less than 0.25%, which meets the required accuracy of the atmospheric correction of ocean color remote sensing. Therefore, the adding-doubling method can be used to generate the exact Rayleigh scattering LUT for the ocean color remote sensors. Finally, the general purpose exact Rayleigh scattering LUT is generated using the adding-doubling method. On the basis of the general purpose LUT, the calculated Rayleigh scattering radiance is tested by comparing with the LUTs ofMODIS, SeaWiFS and the other ocean color sensors, showing that the relative errors are all less than 0.5%, and this general purpose LUT can be applied to all ocean color remote sensors.
基金the Open Project of State Key Laboratory of Automotive Simulation and Control,Jilin University(20161108)the National Natural Science Foundation of China(51505221)the Fundamental Research Funds for the Central Universities(NS2019022).
文摘The BeiDou software receiver uses the fast Fourier transform(FFT)to perform the acquisition.The Doppler shift estimation accuracy should be less than 500 Hz to ensure satellite signals to enter a locked state in the tracking loop.Since the frequency step is usually 500 Hz or larger,the Doppler shift estimation accuracy cannot guarantee that satellite signals are brought into a stable tracking state.The straightforward solutions consist in increasing the sampling time and using zero-padding to improve the frequency resolution of the FFT.However,these solutions intensify the complexity and amount of computation.The contradiction between the acquisition accuracy and the computational load leads us to research for a more simple and effective algorithm,which achieves fine acquisition by a look-up table.After coarse acquisition using the parallel frequency acquisition(PFA)algorithm,the proposed algorithm optimizes the Doppler shift estimation through the look-up table method based on the FFT results to improve the acquisition accuracy of the Doppler shift with a minimal additional computing load.When the Doppler shift is within the queryable range of the table,the proposed algorithm can improve the Doppler shift estimation accuracy to 50 Hz for the BeiDou B1I signal.
基金financially supported by the National Natural Science Foundation of China(11202081,11272124,and 11472109)the State Key Lab of Subtropical Building Science,South China University of Technology(2014ZC17)
文摘Global look-up table strategy proposed recently has been proven to be an efficient method to accelerate the interpolation, which is the most time-consuming part in the iterative sub-pixel digital image correlation （DIC） algorithms. In this paper, a global look-up table strategy with cubic B-spline interpolation is developed for the DIC method based on the inverse compositional Gauss-Newton （IC-GN） algorithm. The performance of this strategy, including accuracy, precision, and computation efficiency, is evaluated through a theoretical and experimental study, using the one with widely employed bicubic interpolation as a benchmark. The global look-up table strategy with cubic B-spline interpolation improves significantly the accuracy of the IC-GN algorithm-based DIC method compared with the one using the bicubic interpolation, at a trivial price of computation efficiency.
基金Project supported by the National Natural Science Foundation of China (Grant No.62205350)the Special Project of Central Government Guiding Local Science and Technology Development in Beijing 2020 (Grant No.Z20111000430000)the Guangxi Nanning Key R&D Program (Grant No.20233067)。
文摘Computer-generated holography technology has been widely applied,and as research in this field deepens,the demand for memory and computational power in small AR and VR devices continues to increase.This paper presents a hologram generation method,i.e.,a symmetrically high-compressed look-up table method,which can reduce memory usage by50%.In offline computing,half of the basic horizontal and vertical modulation factors are stored,halving the memory requirements without affecting inline speed.Currently,its potential extends to various holographic applications,including the production of optical diffraction elements.
基金the National Natural Science Foundation of China(Grant No.41875040)the Top-notch Talents Program in Universities of Anhui Province,China(Grant No.gxbjZD2020067)the Natural Science Research Projects of Universities in Anhui Province,China(Grant No.KJ2020A0029).
文摘Obtaining the vertical distribution profile of trace gas is of great significance for studying the diffusion procedure of air pollution.In this article,a look-up table method based on multi-axis differential optical absorption spectroscopy(MAX-DOAS)technology is established for retrieving the tropospheric NO_(2) vertical distribution profiles.This method retrieves the aerosol extinction profiles with minimum cost function.Then,the aerosol extinction profiles and the atmospheric radiation transfer model(RTM)are employed to establish the look-up table for retrieving the NO_(2) vertical column densities(VCDs)and profiles.The measured NO_(2) differential slant column densities(DSCDs)are compared with the NO_(2) DSCDs simulated by the atmospheric RTM,and the NO_(2) VCDs,the weight factor of NO_(2) in the boundary layer,and the boundary layer height are obtained by the minimization process.The look-up table is established to retrieve NO_(2) VCDs based on MAX-DOAS measurements in Huaibei area,and the results are compared with the data from Copernicus Atmospheric Monitoring Service(CAMS)model.It is found that there are nearly consistent and the correlation coefficient R2 is more than 0.86.The results show that this technology provides a more convenient and accurate retrieval method for the stereoscopic monitoring of atmospheric environment.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3900400)the National Natural Science Foundation of China(Grant Nos.U2142212 and 42361074)。
文摘Accurate satellite data assimilation under all-sky conditions requires enhanced parameterization of scattering properties for frozen hydrometeors in clouds.This study aims to develop a nonspherical scattering look-up table that contains the optical properties of five hydrometeor types—rain,cloud water,cloud ice,graupel,and snow—for the Advanced Radiative Transfer Modeling System(ARMS)at frequencies below 220 GHz.The discrete dipole approximation(DDA)method is employed to compute the single-scattering properties of solid cloud particles,modeling these particles as aggregated roughened bullet rosettes.The bulk optical properties of the cloud layer are derived by integrating the singlescattering properties with a modified Gamma size distribution,specifically for distributions with 18 effective radii.The bulk phase function is then projected onto a series of generalized spherical functions,applying the delta-M method for truncation.The results indicate that simulations using the newly developed nonspherical scattering look-up table exhibit significant consistency with observations under deep convection conditions.In contrast,assuming spherical solid cloud particles leads to excessive scattering at mid-frequency channels and insufficient scattering at high-frequency channels.This improvement in radiative transfer simulation accuracy for cloudy conditions will better support the assimilation of allsky microwave observations into numerical weather prediction models.·Frozen cloud particles were modeled as aggregates of bullet rosettes and the optical properties at microwave range were computed by DDA.·A complete process and technical details for constructing a look-up table of ARMS are provided.·The ARMS simulations generally show agreement with observations of MWTS and MWHS under typhoon conditions using the new look-up table.
文摘In this paper, we explore the possibility of mapping devices designed in TCAD environment to its modeled version developed in cadence virtuoso environment using a look-up table （LUT） approach. Circuit simu- lation of newly designed devices in TCAD environment is a very slow and tedious process involving complex scripting. Hence, the LUT based modeling approach has been proposed as a faster and easier alternative in ca- dence environment. The LUTs are prepared by extracting data from the device characteristics obtained from device simulation in TCAD. A comparative study is shown between the TCAD simulation and the LUT-based alternative to showcase the accuracy of modeled devices. Finally the look-up table approach is used to evaluate the perform- ance of circuits implemented using 14 nm nMOSFET.
基金Supported by the National High-Tech Research and Development Program of China("863")(Grant No.2006AA020803)
文摘A method has been developed to establish the crystal position look-up table for positron emission tomography with block detectors.It is based on the principle that the counts in crystal position histogram obey the Gaussian mixture model(GMM).This method has taken full consideration of the characteristics of the GMM and the detector itself.The experimental results have proved that it is simple,reliable,and universal.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.41875040,41705012,and 1605013)
文摘A method for aerosol extinction profile retrieval using ground-based multi-axis differential optical absorption spectroscopy(MAX-DOAS)is studied,which is based on a look-up table algorithm.The algorithm uses parametric method to represent aerosol extinction profiles and simulate different atmospheric aerosol states through atmospheric radiation transfer model.Based on the method,aerosol extinction profile was obtained during six cloud-free days.The O4 differential air mass factor(dAMF)measured by MAX-DOAS is compared with the corresponding model results under different atmospheric conditions(R^2=0.78).The aerosol optical thickness,aerosol weight factor in boundary layer,and the height of the boundary layer are obtained after the process of minimization and look-up table method.The retrieved aerosol extinction in boundary layer is compared with PM2.5 data measured by ground point instrument.The diurnal variation trends of the two methods are in good agreement.The correlation coefficients of the two methods are 0.71 when the aerosol optical thickness is smaller than 0.5.The results show that the look-up table method can obtain the aerosol state of the troposphere and provide validation for other instrument data.
文摘Presently, there are mainly two problems that prevent Electric Vehicles (EVs) from becoming popular against the Internal Combustion Engine Vehicles (ICEVs), namely: short range and too long to recharge the battery pack of the EV. Due to this, battery development is a crucial aspect to improve the performance of EVs. This progress requires dependable computer aided designs to model the characteristics of a battery accurately and reliably. This paper uses Power Systems Computer Aided Design (PSCAD) to create an equivalent runtime circuit model to observe the qualities of the Lithium Iron Phosphate battery cell under discharge at different temperatures. The model is a 3-R-C branch runtime equivalent circuit model. In order to find the fixed parameters of the circuit, MATLAB was used to implement basic current voltage characteristics. 3-D tables have been used in PSCAD to implement the State of Charge (SOC) and temperature dependent circuit parameters of the model. Once the simulations for all temperatures were completed, the average marginal error between measured and simulated terminal voltage came to be 2.1%, therefore making PSCAD an accurate simulation tool for modeling equivalent circuits of different batteries.
基金supported by the National Natural Science Foun-dation of China (No. 51074169)
文摘Laser triangulation theory was used to develop a novel contact-free method for measuring the coal level in a silo under harsh environmental conditions found in coal mines, such as the presence of dense dust, high humidity, and low illumination. A laser source and a camera were mounted at the top of the silo. The laser spot projected into the silo was imaged by the camera. The pinhole imaging principle allows the level to be found from the lateral shift of the spot image on the sensor. A pre-calibrated look-up table of the coal depth versus spot position was used to obtain the depth. The measurement accuracy depends on the step size used during pre-calibration. The actual application of a device designed according to these principles shows that it is easy to implement. The detection of the coal level in a silo at the low illumination level found in coal mines is demonstrated.
基金Supported by the National Natural Science Foundation of China (No. 60972064)
文摘In this paper,a Radio Over Fiber (ROF) system with a Digital Pre-Distorter (DPD) for WCDMA signal transmission is investigated.A Look-Up Table (LUT) based DPD and a Memory Polynomial (MP) DPD are applied in the ROF link so as to suppress the out-of-band spurious spectrum and improve the transmission performance.The experimental results show that the out-of-band emission due to existence of the third-order Inter-Modulation Distortion (IMD3) is obviously sup-pressed by these two DPD.An Adjacent Channel Power Ratio (ACPR) improvement of 8 dB is ob-tained for a single-carrier WCDMA signal transmission.These two DPD have equal ability in lin-earization of the ROF system for a three-carrier WCDMA signal transmission.There is no apparent memory effects exist in the ROF link.
文摘An intelligent fuzzy logic inference pipeline for the control of a dc-dc buck-boost converter was designed and built using a semi-custom VLSI chip. The fuzzy linguistics describing the switching topologies of the converter was mapped into a look-up table that was synthesized into a set of Boolean equations. A VLSI chip–a field programmable gate array (FPGA) was used to implement the Boolean equations. Features include the size of RAM chip independent of number of rules in the knowledge base, on-chip fuzzification and defuzzification, faster response with speeds over giga fuzzy logic inferences per sec (FLIPS), and an inexpensive VLSI chip. The key application areas are: 1) on-chip integrated controllers;and 2) on-chip co-integration for entire system of sensors, circuits, controllers, and detectors for building complete instrument systems.
文摘A real time mixing module for high definition television (HDTV) data of SMPTE 274M and PC video data is designed. The hardware implementation, algorithm and simulation of the mixing module are given. In order to improve the capability of data processing, an anti-fuse FPGA chip and a mechanism of pipelining and modularization are adopted. With 6 parallel LUTs and a fast algorithm, it can mix 4∶2∶2 component signals in luminance and chrominance space respectively in real time. According to the simulation, the module has the ability to mix the uncompressed HDTV data with PC video data in real time, which can not be fulfilled by current ASIC chips. Furthermore, it can be extended to multi-stage mixing with the thoughts implied by the design. The mixing module can be widely used in HDTV production systems.
