Laser-induced fluorescence(LIF)spectroscopy is employed for plasma diagnosis,necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal.However,direct deconvol...Laser-induced fluorescence(LIF)spectroscopy is employed for plasma diagnosis,necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal.However,direct deconvolution becomes invalid in the presence of noise as it leads to infinite amplification of high-frequency noise components.To address this issue,we propose a deconvolution algorithm based on the maximum entropy principle.We validate the effectiveness of the proposed algorithm by utilizing simulated LIF spectra at various noise levels(signal-to-noise ratio,SNR=20–80 d B)and measured LIF spectra with Xe as the working fluid.In the typical measured spectrum(SNR=26.23 d B)experiment,compared with the Gaussian filter and the Richardson–Lucy(R-L)algorithm,the proposed algorithm demonstrates an increase in SNR of 1.39 d B and 4.66 d B,respectively,along with a reduction in the root-meansquare error(RMSE)of 35%and 64%,respectively.Additionally,there is a decrease in the spectral angle(SA)of 0.05 and 0.11,respectively.In the high-quality spectrum(SNR=43.96 d B)experiment,the results show that the running time of the proposed algorithm is reduced by about98%compared with the R-L iterative algorithm.Moreover,the maximum entropy algorithm avoids parameter optimization settings and is more suitable for automatic implementation.In conclusion,the proposed algorithm can accurately resolve Doppler spectrum details while effectively suppressing noise,thus highlighting its advantage in LIF spectral deconvolution applications.展开更多
Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty ...Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty are synthesized in the so-called probability of failure.This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint.In view of this issue,this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments.The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion.Then,failure probabilities are estimated employing maximum entropy distribution with fractional moments.The application of the proposed approach is examined with two examples:a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope.The results show that the proposed approach has excellent accuracy and high efficiency,and it can be applied straightforwardly to similar geotechnical engineering problems.展开更多
In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feas...In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feasible solution of first-level subarray tiling and employs the particle swarm algorithm to optimize the conformal array subarray tiling scheme with the maximum entropy of the planar mapping as the fitness function.Subsequently,convex optimization is applied to optimize the subarray amplitude phase.Data results verify that the method can effectively find the optimal conformal array tiling scheme.展开更多
Taking the Dapingzhang copper-polymetallic deposit in Yunnan Province, China as the research object, the maximum entropy model was used to extract the mining information, and the mineral resource prediction model was ...Taking the Dapingzhang copper-polymetallic deposit in Yunnan Province, China as the research object, the maximum entropy model was used to extract the mining information, and the mineral resource prediction model was established by using the exploration data of the deposit and related regions in this area, so as to determine the prospecting prospect area in the study area. In this paper, the Jacknife analysis module of maximum entropy model is used to quantitatively rank the importance of 39 geochemical element variables, and finally obtain the prospecting prospect map of the study area. The research results show that the Dapingzhang mining area has the potential to find hidden ore in the deep and surrounding areas, and the northern and southern ends and western sides of the rock ore control structural belt in the eastern region of the mining area have good prospecting prospects. The research results provide an important basis for the deployment of follow-up exploration work in the study area, and the maximum entropy model has a good application effect in mineral resources exploration.展开更多
The survival of agroforestry tree species in sub-Saharan Africa is essential for sustainable livelihoods, particularly in the semi-arid environment. Drought in the Agroecological zones (AEZ) of Nigeria is one of the e...The survival of agroforestry tree species in sub-Saharan Africa is essential for sustainable livelihoods, particularly in the semi-arid environment. Drought in the Agroecological zones (AEZ) of Nigeria is one of the environmental factors limiting parkland tree regeneration. Species distribution modelling offers the opportunity to predict future distributions of plant species based on current distribution data and bioclimatic variables. Maxent (maximum entropy) model was employed to predict the future tree distribution in AEZ parklands, under the four Representative Concentration Pathway (RCP) climate change prediction using current tree distribution (presence-only data) along a transect across three agroecological zones. The spatial data used were 19 bioclimatic variables and presence-only data for the two most important tree species—Parkia biglobosa and Vitellaria paradoxa. The result showed a drastic reduction (>45%) in the suitability of farmlands across predictions observed in the studied agroecological zones. The 2050 scenario in both species predicted areas had an increasing mid-range potential, over 44% lower suitability in sampled AEZ distribution predictions. The future prediction potential distribution maps for year 2070 of both species displayed large variations in suitability compared to 2050, showing a significant increase (up to 53%) in areas climatically suitable for both species to regenerate and thrive. This is attributed to over increased annual evapotranspiration, despite increasing seasonal precipitation. This study highlights the need for more climate-smart regeneration and improved restoration strategies to reduce land degradation as climate conditions change over time.展开更多
为全面评价生态气候因子对湖北省烟叶生长发育的影响,利用2008—2020年中国气象局陆面数据同化系统(CMA land data assimilation system,CLDAS)数据集和其他环境因子,基于最大熵模型(MaxEnt),利用湖北省西部烟区实际种植点位模拟湖北省...为全面评价生态气候因子对湖北省烟叶生长发育的影响,利用2008—2020年中国气象局陆面数据同化系统(CMA land data assimilation system,CLDAS)数据集和其他环境因子,基于最大熵模型(MaxEnt),利用湖北省西部烟区实际种植点位模拟湖北省烟区的潜在适宜性分布,并评估影响适宜性分布的主导环境因子。结果显示:MaxEnt模型对烟草适宜性分布的模拟预测精度较高(AUC=0.854)。海拔(650~1750 m)、土壤类型(黄壤)、团棵期平均最低气温(8.9~15.0℃)、旺长期平均气温(16.0~22.9℃)、成熟期平均气温(18.8~25.6℃)是影响湖北烟草分布的主导环境因子。烟草的高适生区主要分布在恩施、十堰和襄阳南部及宜昌东南部,占湖北省总面积的18.2%,80%区域的海拔为700~1350 m、团棵期平均最低气温11.2~14.5℃、旺长期平均气温19.2~22.8℃、成熟期平均气温22.0~25.4℃。在所有环境因子中,海拔高度起决定性作用,温度则是影响烟草生长发育的重要气象因子。研究表明,本研究结果与湖北烟区实际空间分布基本相符。展开更多
In the multilevel thresholding segmentation of the image, the classification number is always given by the supervisor. To solve this problem, a fast multilevel thresholding algorithm considering both the threshold val...In the multilevel thresholding segmentation of the image, the classification number is always given by the supervisor. To solve this problem, a fast multilevel thresholding algorithm considering both the threshold value and the classification number is proposed based on the maximum entropy, and the self-adaptive criterion of the classification number is given. The algorithm can obtain thresholds and automatically decide the classification number. Experimental results show that the algorithm is effective.展开更多
The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis...The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus.展开更多
Based on the maximum entropy principle a new probability density function （PDF） f（x） for the surface elevation of nonlinear sea waves, X, is derived through performing a coordinate transform of X and solving a var...Based on the maximum entropy principle a new probability density function （PDF） f（x） for the surface elevation of nonlinear sea waves, X, is derived through performing a coordinate transform of X and solving a variation problem subject to three constraint conditions of f（ x ）. Compared with the maximum entropy PDFs presented previously, the new PDF has the following merits： （1） it has four parameters to be determined and hence can give more refined fit to observed data and has wider suitability for nonlinear waves in different conditions; （2） these parameters are expressed in terms of distribution moments of X in a relatively simple form and hence are easy to be determined from observed data; （3） the PDF is free of the restriction of weak nonlinearity and possible to be used for sea waves in complicated conditions, such as those in shallow waters with complicated topography; and （4） the PDF is simple in form and hence convenient for theoretical and practical uses. l.aboratory wind-wave experiments have been conducted to test the competence of the new PDF for the surface elevation of nonlinear waves. The experimental results manifest that the new PDF gives somewhat better fit to the laboratory wind-wave data than the well-known Gram-Charlier PDF and beta PDF.展开更多
文摘Laser-induced fluorescence(LIF)spectroscopy is employed for plasma diagnosis,necessitating the utilization of deconvolution algorithms to isolate the Doppler effect from the raw spectral signal.However,direct deconvolution becomes invalid in the presence of noise as it leads to infinite amplification of high-frequency noise components.To address this issue,we propose a deconvolution algorithm based on the maximum entropy principle.We validate the effectiveness of the proposed algorithm by utilizing simulated LIF spectra at various noise levels(signal-to-noise ratio,SNR=20–80 d B)and measured LIF spectra with Xe as the working fluid.In the typical measured spectrum(SNR=26.23 d B)experiment,compared with the Gaussian filter and the Richardson–Lucy(R-L)algorithm,the proposed algorithm demonstrates an increase in SNR of 1.39 d B and 4.66 d B,respectively,along with a reduction in the root-meansquare error(RMSE)of 35%and 64%,respectively.Additionally,there is a decrease in the spectral angle(SA)of 0.05 and 0.11,respectively.In the high-quality spectrum(SNR=43.96 d B)experiment,the results show that the running time of the proposed algorithm is reduced by about98%compared with the R-L iterative algorithm.Moreover,the maximum entropy algorithm avoids parameter optimization settings and is more suitable for automatic implementation.In conclusion,the proposed algorithm can accurately resolve Doppler spectrum details while effectively suppressing noise,thus highlighting its advantage in LIF spectral deconvolution applications.
基金funding support from the China Scholarship Council(CSC).
文摘Spatial variability of soil properties imposes a challenge for practical analysis and design in geotechnical engineering.The latter is particularly true for slope stability assessment,where the effects of uncertainty are synthesized in the so-called probability of failure.This probability quantifies the reliability of a slope and its numerical calculation is usually quite involved from a numerical viewpoint.In view of this issue,this paper proposes an approach for failure probability assessment based on Latinized partially stratified sampling and maximum entropy distribution with fractional moments.The spatial variability of geotechnical properties is represented by means of random fields and the Karhunen-Loève expansion.Then,failure probabilities are estimated employing maximum entropy distribution with fractional moments.The application of the proposed approach is examined with two examples:a case study of an undrained slope and a case study of a slope with cross-correlated random fields of strength parameters under a drained slope.The results show that the proposed approach has excellent accuracy and high efficiency,and it can be applied straightforwardly to similar geotechnical engineering problems.
基金supported by the Advanced Functional Composites Technology Key Laboratory Fund under Grant No.6142906220404Sichuan Province Centralized Guided Local Science and Technology Development Special Project under Grant No.2022ZYD0121。
文摘In this paper,an effective algorithm for optimizing the subarray of conformal arrays is proposed.The method first divides theconformal array into several first-level subarrays.It uses the X algorithm to solve the feasible solution of first-level subarray tiling and employs the particle swarm algorithm to optimize the conformal array subarray tiling scheme with the maximum entropy of the planar mapping as the fitness function.Subsequently,convex optimization is applied to optimize the subarray amplitude phase.Data results verify that the method can effectively find the optimal conformal array tiling scheme.
文摘湖南省是白颈长尾雉(Syrmaticus ellioti)的主要栖息地之一,分析其潜在适生区对该物种保护具有现实指导意义。本研究综合考虑地形、水源、气候、植被、土地类型以及人为干扰等多项因子,结合有效的白颈长尾雉分布点,利用最大熵(maximum entropy, Maxent)模型预测湖南省白颈长尾雉的适宜栖息地。结果显示, Maxent模型10次重复运行训练集的平均曲线下面积(area under the curve, AUC)值为0.964,预测结果优秀;到县道距离(dis_x)、最暖季度降水量(bio18)、到混交林距离(dis_mxf)和平均气温日较差(bio2)是影响白颈长尾雉适宜栖息地分布的主要因子,到稀树草原距离(dis_sav)、海拔(altitude)和到荒地距离(dis_bar)对其分布的影响也较大,其余因子具有一定影响但并不显著;白颈长尾雉适生区面积为4.76×10^(4)km^(2),主要位于湘西、湘南的山地,但适宜栖息地破碎化程度较高,整体较为分散。
文摘Taking the Dapingzhang copper-polymetallic deposit in Yunnan Province, China as the research object, the maximum entropy model was used to extract the mining information, and the mineral resource prediction model was established by using the exploration data of the deposit and related regions in this area, so as to determine the prospecting prospect area in the study area. In this paper, the Jacknife analysis module of maximum entropy model is used to quantitatively rank the importance of 39 geochemical element variables, and finally obtain the prospecting prospect map of the study area. The research results show that the Dapingzhang mining area has the potential to find hidden ore in the deep and surrounding areas, and the northern and southern ends and western sides of the rock ore control structural belt in the eastern region of the mining area have good prospecting prospects. The research results provide an important basis for the deployment of follow-up exploration work in the study area, and the maximum entropy model has a good application effect in mineral resources exploration.
文摘The survival of agroforestry tree species in sub-Saharan Africa is essential for sustainable livelihoods, particularly in the semi-arid environment. Drought in the Agroecological zones (AEZ) of Nigeria is one of the environmental factors limiting parkland tree regeneration. Species distribution modelling offers the opportunity to predict future distributions of plant species based on current distribution data and bioclimatic variables. Maxent (maximum entropy) model was employed to predict the future tree distribution in AEZ parklands, under the four Representative Concentration Pathway (RCP) climate change prediction using current tree distribution (presence-only data) along a transect across three agroecological zones. The spatial data used were 19 bioclimatic variables and presence-only data for the two most important tree species—Parkia biglobosa and Vitellaria paradoxa. The result showed a drastic reduction (>45%) in the suitability of farmlands across predictions observed in the studied agroecological zones. The 2050 scenario in both species predicted areas had an increasing mid-range potential, over 44% lower suitability in sampled AEZ distribution predictions. The future prediction potential distribution maps for year 2070 of both species displayed large variations in suitability compared to 2050, showing a significant increase (up to 53%) in areas climatically suitable for both species to regenerate and thrive. This is attributed to over increased annual evapotranspiration, despite increasing seasonal precipitation. This study highlights the need for more climate-smart regeneration and improved restoration strategies to reduce land degradation as climate conditions change over time.
文摘为全面评价生态气候因子对湖北省烟叶生长发育的影响,利用2008—2020年中国气象局陆面数据同化系统(CMA land data assimilation system,CLDAS)数据集和其他环境因子,基于最大熵模型(MaxEnt),利用湖北省西部烟区实际种植点位模拟湖北省烟区的潜在适宜性分布,并评估影响适宜性分布的主导环境因子。结果显示:MaxEnt模型对烟草适宜性分布的模拟预测精度较高(AUC=0.854)。海拔(650~1750 m)、土壤类型(黄壤)、团棵期平均最低气温(8.9~15.0℃)、旺长期平均气温(16.0~22.9℃)、成熟期平均气温(18.8~25.6℃)是影响湖北烟草分布的主导环境因子。烟草的高适生区主要分布在恩施、十堰和襄阳南部及宜昌东南部,占湖北省总面积的18.2%,80%区域的海拔为700~1350 m、团棵期平均最低气温11.2~14.5℃、旺长期平均气温19.2~22.8℃、成熟期平均气温22.0~25.4℃。在所有环境因子中,海拔高度起决定性作用,温度则是影响烟草生长发育的重要气象因子。研究表明,本研究结果与湖北烟区实际空间分布基本相符。
文摘In the multilevel thresholding segmentation of the image, the classification number is always given by the supervisor. To solve this problem, a fast multilevel thresholding algorithm considering both the threshold value and the classification number is proposed based on the maximum entropy, and the self-adaptive criterion of the classification number is given. The algorithm can obtain thresholds and automatically decide the classification number. Experimental results show that the algorithm is effective.
基金the auspices of A Category of Strategic Priority Research Program of Chinese Academy of Sciences(No.XDA20010101)。
文摘The spatial interaction model is an effective way to explore the geographical disparities inherent in the Belt and Road Initiative(BRI) by simulating spatial flows. The traditional gravity model implies the hypothesis of equilibrium points without any reference to when or how to achieve it. In this paper, a dynamic gravity model was established based on the Maximum Entropy(MaxEnt) theory to estimate and monitor the interconnection intensity and dynamic characters of bilateral relations. In order to detect the determinants of interconnection intensity, a Geodetector method was applied to identify and evaluate the determinants of spatial networks in five dimensions. The empirical study clearly demonstrates a heterogeneous and non-circular spatial structure. The main driving forces of spatial-temporal evolution are foreign direct investment, tourism and railway infrastructure construction, while determinants in different sub-regions show obvious spatial differentiation. Southeast Asian countries are typically multi-island area where aviation infrastructure plays a more important role. North and Central Asian countries regard oil as a pillar industry where power and port facilities have a greater impact on the interconnection. While Western Asian countries are mostly influenced by the railway infrastructure, Eastern European countries already have relatively robust infrastructure where tariff policies provide a greater impetus.
基金This workis financially supported by the National Natural Science Foundation of China (Grant No.40490263 andNo.40276006)
文摘Based on the maximum entropy principle a new probability density function （PDF） f（x） for the surface elevation of nonlinear sea waves, X, is derived through performing a coordinate transform of X and solving a variation problem subject to three constraint conditions of f（ x ）. Compared with the maximum entropy PDFs presented previously, the new PDF has the following merits： （1） it has four parameters to be determined and hence can give more refined fit to observed data and has wider suitability for nonlinear waves in different conditions; （2） these parameters are expressed in terms of distribution moments of X in a relatively simple form and hence are easy to be determined from observed data; （3） the PDF is free of the restriction of weak nonlinearity and possible to be used for sea waves in complicated conditions, such as those in shallow waters with complicated topography; and （4） the PDF is simple in form and hence convenient for theoretical and practical uses. l.aboratory wind-wave experiments have been conducted to test the competence of the new PDF for the surface elevation of nonlinear waves. The experimental results manifest that the new PDF gives somewhat better fit to the laboratory wind-wave data than the well-known Gram-Charlier PDF and beta PDF.
