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基于条件高斯PAC-Bayes的机载CNN分类器安全性评估 被引量:1
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作者 马赞 白杰 +2 位作者 陈勇 刘瑞华 张艳婷 《航空学报》 北大核心 2025年第4期217-230,共14页
针对机器学习技术的固有不确定输出特性给航空器适航安全性定量评估造成的挑战,在SAE ARP4761标准框架下,基于条件高斯PAC-Bayes泛化理论提出一种面向卷积神经网络(CNN)分类功能的系统安全性评估方法。首先,基于PAC-Bayes理论,通过条件... 针对机器学习技术的固有不确定输出特性给航空器适航安全性定量评估造成的挑战,在SAE ARP4761标准框架下,基于条件高斯PAC-Bayes泛化理论提出一种面向卷积神经网络(CNN)分类功能的系统安全性评估方法。首先,基于PAC-Bayes理论,通过条件高斯分布改进训练方法,优化泛化界,获取CNN模型不确定性量化表示。其次,提出一种基于泛化界置信度的软件不确定性与硬件可靠性融合方法,获取CNN部件的综合失效基础数据,支持整机/系统的定量安全性评估。最后,以基于CNN的全球导航卫星系统干扰信号识别模块装机为案例,表明该方法对适航安全性评估的有效支撑作用,为CNN技术的装机应用提供了必要的适航符合性保证。同时也实验验证基于条件高斯的方法比标准PAC-Bayes及Vapnik-Chervonenkis维都具有更紧的计算边界。 展开更多
关键词 机载CNN分类器 PAC-bayes SAE ARP4761 条件高斯 适航安全性
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基于随机建模与Bayes推断的结构热传导数字孪生建模方法研究
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作者 李建宇 付介祥 +1 位作者 郝鑫野 李广利 《应用数学和力学》 北大核心 2025年第8期983-998,共16页
极端热环境条件下结构传热温度场的准确预测是评估装备热⁃力耦合性能的关键基础.数字孪生(digital twin)技术通过对观测数据与仿真模型的深度融合,可实现温度场的高精度动态重构.然而,考虑观测噪声、模型参数不确定性、边界条件扰动等... 极端热环境条件下结构传热温度场的准确预测是评估装备热⁃力耦合性能的关键基础.数字孪生(digital twin)技术通过对观测数据与仿真模型的深度融合,可实现温度场的高精度动态重构.然而,考虑观测噪声、模型参数不确定性、边界条件扰动等多源不确定性因素的结构传热温度场预测数字孪生模型目前还不多见.该文基于Bayes推断框架,提出了一种结合随机传热分析的数据与模型融合方法,旨在构建考虑不确定性量化的热传导数字孪生模型.首先,在热传导方程中引入随机扰动热源项,以模拟未被原模型量化表征的不确定性因素;其次,采用随机有限元方法求解随机扰动热传导模型,获得包含物理信息的温度场先验分布;最后,基于Bayes法则,将含噪声的观测数据与模型预测先验分布进行融合,并针对Gauss分布情形推导出温度场后验分布的解析表达式.通过一维和二维热传导算例验证,所提方法不仅能够实现对温度场的高精度预测,还可有效量化预测结果的不确定性. 展开更多
关键词 热传导分析 数字孪生 随机有限元 bayES推断 不确定性量化
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双定时混合截尾下双参数指数分布参数的Bayes估计
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作者 牟悦嘉 李云飞 《西华师范大学学报(自然科学版)》 2025年第5期492-498,共7页
在双定时混合截尾场合下,针对双参数指数分布,首先研究了门限参数(μ)和尺度参数(θ)的极大似然估计。然后讨论了μ已知时,θ在3种损失函数下的Bayes估计和E-Bayes估计,结合遗传算法得到了共轭先验分布中超参数的最优值,数值模拟表明遗... 在双定时混合截尾场合下,针对双参数指数分布,首先研究了门限参数(μ)和尺度参数(θ)的极大似然估计。然后讨论了μ已知时,θ在3种损失函数下的Bayes估计和E-Bayes估计,结合遗传算法得到了共轭先验分布中超参数的最优值,数值模拟表明遗传算法能够更加准确地估计超参数,从而提高参数Bayes估计的精度。最后研究了μ和θ均未知时两个参数的Bayes估计,数值模拟表明两参数的Bayes估计精度高于极大似然估计精度。 展开更多
关键词 双参数指数分布 双定时混合截尾 极大似然估计 bayES估计 E-bayES估计
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k阶Erlang分布参数在加权p、q对称熵损失下的Bayes估计
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作者 季海波 《淮阴师范学院学报(自然科学版)》 2025年第2期102-106,共5页
研究了k阶Erlang分布的参数在加权p、q对称熵损失下的Bayes估计问题.在不同先验分布下给出了参数的Bayes估计的精确形式,进一步研究了Gamma先验分布情形下多层Bayes估计和E-Bayes估计,并运用Monte-Carlo模拟方法验证了各个Bayes估计的... 研究了k阶Erlang分布的参数在加权p、q对称熵损失下的Bayes估计问题.在不同先验分布下给出了参数的Bayes估计的精确形式,进一步研究了Gamma先验分布情形下多层Bayes估计和E-Bayes估计,并运用Monte-Carlo模拟方法验证了各个Bayes估计的合理性. 展开更多
关键词 ERLANG分布 加权p、q对称熵损失 bayES估计 Monte-Carlo模拟
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SPOT和Bayes递推估计融合的运载火箭样本量设计
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作者 黄彭奇子 段晓君 张银辉 《国防科技大学学报》 北大核心 2025年第1期207-213,共7页
针对运载火箭小子样条件,结合序贯验后加权检验(sequential posterior odd test, SPOT)和Bayes递推估计法,分别从假设检验和参数估计两方面,对传统试验样本量评估方法进行改进。在对运载火箭服从正态分布的性能指标进行评估时,引入复合... 针对运载火箭小子样条件,结合序贯验后加权检验(sequential posterior odd test, SPOT)和Bayes递推估计法,分别从假设检验和参数估计两方面,对传统试验样本量评估方法进行改进。在对运载火箭服从正态分布的性能指标进行评估时,引入复合等效系数来有效融合多源数据,弥补真实试验数据或现场数据的不足。综合考虑两类风险和置信度要求,制定合理的评估方案,有效减少所需试验样本数量,从而控制试验成本。通过算例分析发现,提出样本量评估方法结果真实可信,能够有效降低样本量需求,可较好用于小子样条件下的运载火箭样本量试验设计。 展开更多
关键词 样本量评估 SPOT bayES估计
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基于Bayes推断的COVID-19流行病干预政策评估
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作者 罗俊藤 唐明 《华东师范大学学报(自然科学版)》 北大核心 2025年第3期157-166,共10页
为应对2019年新型冠状病毒病(corona virus disease 2019,COVID-19)的大流行,全球197个国家采取了各种防控政策,取得了不同程度的抑制效果.许多学者利用数学建模分析了各种非药物干预和疫苗接种政策对COVID-19传播的影响,但这些研究主... 为应对2019年新型冠状病毒病(corona virus disease 2019,COVID-19)的大流行,全球197个国家采取了各种防控政策,取得了不同程度的抑制效果.许多学者利用数学建模分析了各种非药物干预和疫苗接种政策对COVID-19传播的影响,但这些研究主要侧重于定量评估干预政策对COVID-19再生数的影响.建立了一个双层Bayes模型,并基于Bayes推断分别定量评估了不同政策对COVID-19感染和恢复过程影响的有效性;将干预措施分为公共卫生干预政策和管控政策两大类.结果显示,两类干预政策都可以降低COVID-19的感染率,提高COVID-19的恢复率;但干预政策的类型对传播过程和恢复过程的影响有明显的倾向性,即公共卫生干预政策更有助于COVID-19的恢复过程,大多数管控政策及部分公共卫生措施对COVID-19的传播过程影响较大. 展开更多
关键词 COVID-19 传播 恢复 bayES推断 政策评估
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基于Bayes超参数优化梯度提升树的心脏病预测方法
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作者 王海燕 焦增晨 +2 位作者 赵剑 安天博 鞠熠 《吉林大学学报(理学版)》 北大核心 2025年第2期472-478,共7页
针对传统机器学习算法在数据集Cleveland和Hungary上预测准确率低的问题,提出一种基于Bayes超参数优化梯度提升树的心脏病预测方法.首先,采用K-最近邻算法对数据集中的缺失值进行填补,用Min-Max标准化、One-Hot编码处理数据,并基于梯度... 针对传统机器学习算法在数据集Cleveland和Hungary上预测准确率低的问题,提出一种基于Bayes超参数优化梯度提升树的心脏病预测方法.首先,采用K-最近邻算法对数据集中的缺失值进行填补,用Min-Max标准化、One-Hot编码处理数据,并基于梯度提升树算法进行心脏病预测;其次,采用Bayes优化和十倍交叉验证的方式搜寻算法的最佳超参数组合.实验结果表明,优化后的梯度提升树算法在心脏病数据集Cleveland上预测准确率可达90.2%,在心脏病数据集Hungary上预测准确率可达81.4%,优于决策树、支持向量机、K-最近邻等传统机器学习方法,可辅助医生进行心脏病诊断. 展开更多
关键词 心脏病预测 K-最近邻算法 梯度提升树 bayes优化
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双定数混合截尾下Lomax分布参数的Bayes估计
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作者 韩旭 李云飞 《西华师范大学学报(自然科学版)》 2025年第3期263-268,共6页
在双定数混合截尾试验下,针对双参数Lomax分布,求出了形状参数的极大似然估计,研究了形状参数的Bayes估计。当尺度参数已知,取形状参数的先验分布为Gamma分布时,在4种不同损失函数下,给出了形状参数的Bayes估计,并结合粒子群算法寻找最... 在双定数混合截尾试验下,针对双参数Lomax分布,求出了形状参数的极大似然估计,研究了形状参数的Bayes估计。当尺度参数已知,取形状参数的先验分布为Gamma分布时,在4种不同损失函数下,给出了形状参数的Bayes估计,并结合粒子群算法寻找最优超参数。最后,在各种损失函数下,对形状参数Bayes估计值的平均相对误差进行比较。数值分析结果表明,粒子群算法能更加准确高效地确定超参数,使得在不同损失函数下形状参数的Bayes估计更加精确。 展开更多
关键词 Lomax分布 双定数混合截尾 极大似然估计 bayES估计 粒子群算法
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加权p、q对称损失函数下Topp-Leone分布的Bayes估计
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作者 王佳旭 徐宝 《井冈山大学学报(自然科学版)》 2025年第5期1-11,共11页
该文针对加权p、q对称损失函数的场景,运用Bayes参数估计法,对Topp-Leone分布参数的贝叶斯估计形式与性质展开探究。并针对无信息先验分布与共轭先验分布两种情形,成功推导出了参数估计量的精确表达式,从理论上验证了这些估计的可容许... 该文针对加权p、q对称损失函数的场景,运用Bayes参数估计法,对Topp-Leone分布参数的贝叶斯估计形式与性质展开探究。并针对无信息先验分布与共轭先验分布两种情形,成功推导出了参数估计量的精确表达式,从理论上验证了这些估计的可容许性及最小最大估计。经过计算,得到了多层Bayes估计、刀切Bayes估计以及经验Bayes估计。最后,利用R语言软件结合MCMC算法对这些估计进行数值模拟,结果表明,无信息先验分布下的Bayes估计在精度方面优于共轭先验分布下的Bayes估计。 展开更多
关键词 Topp-Leone分布 加权p、q对称损失函数 bayES估计 可容许性 MCMC算法
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加权平方损失函数下Rayleigh分布参数的刀切Bayes估计
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作者 于雪松 徐宝 《淮阴师范学院学报(自然科学版)》 2025年第2期95-101,115,共8页
利用刀切法和Bayes估计方法,在加权平方损失函数下,得到Rayleigh分布在选取先验分布为Jefferys无信息分布和Gamma分布的情况下参数的Bayes估计的精确形式,在此基础上进一步研究了参数的刀切Bayes估计.最后在R软件中运用MCMC(Markov Chai... 利用刀切法和Bayes估计方法,在加权平方损失函数下,得到Rayleigh分布在选取先验分布为Jefferys无信息分布和Gamma分布的情况下参数的Bayes估计的精确形式,在此基础上进一步研究了参数的刀切Bayes估计.最后在R软件中运用MCMC(Markov Chain Monte Carlo)算法对Rayleigh分布参数的Bayes估计和刀切Bayes估计进行数值模拟.模拟结果显示:当样本容量较大时,相同先验分布下刀切Bayes估计模拟效果更好. 展开更多
关键词 RAYLEIGH分布 加权平方损失函数 刀切bayes估计 MCMC算法
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基于Bayes判别准则的风电场等值误差阈值最小风险量化方法
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作者 朱乾龙 金小强 +3 位作者 王绪利 苏凡亚 邓天白 陶骏 《中国电力》 北大核心 2025年第4期98-106,共9页
等值误差阈值是平衡风电场模型数学复杂度与仿真速度的基石,可推动风电场等值模型的标准化进程。世界主要风电大国在量化风电模型误差阈值方面的出发点和侧重点不同,误差阈值的形式及指标尚未统一。为此,从理论层面提出一种基于Bayes判... 等值误差阈值是平衡风电场模型数学复杂度与仿真速度的基石,可推动风电场等值模型的标准化进程。世界主要风电大国在量化风电模型误差阈值方面的出发点和侧重点不同,误差阈值的形式及指标尚未统一。为此,从理论层面提出一种基于Bayes判别准则的风电场等值误差阈值最小风险量化方法。首先,以等值误差的时间分布特性为切入点,量化不同时段内风电场等值模型的欧几里得误差,进而通过核密度估计拟合上述误差的概率密度分布。然后,使用实时加权先验概率算法获取风电场模型有效的先验概率,并计及模型有效性漏判和误判给电力系统带来的不同损失,基于Bayes判别准则建立面向最小风险的风电场等值误差阈值量化模型。最后,以某实际风电场算例进行分析,验证了所提方法的可行性,与国内外误差阈值相比,所提方法可更加快速、准确地判定风电场等值模型的有效性。 展开更多
关键词 风电场等值误差 阈值量化 bayes判别准则 先验概率 判别损失比
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混频数据分位回归模型的Bayes分析
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作者 董小刚 叶盼盼 +1 位作者 袁晓惠 孙长智 《吉林大学学报(理学版)》 北大核心 2025年第5期1313-1324,共12页
针对混频数据的建模问题,提出自回归U-MIDAS(unrestricted mixed data sampling)分位回归模型.首先,结合嵌套Lasso惩罚方法及spike-and-slab先验进行Bayes参数估计和变量选择;其次,通过数值模拟证明该方法的优越性;最后,将该方法用于美... 针对混频数据的建模问题,提出自回归U-MIDAS(unrestricted mixed data sampling)分位回归模型.首先,结合嵌套Lasso惩罚方法及spike-and-slab先验进行Bayes参数估计和变量选择;其次,通过数值模拟证明该方法的优越性;最后,将该方法用于美国名义国内生产总值(GDP)年化季度增长率的预测,结果表明,该方法预测精度较好. 展开更多
关键词 混频数据 自回归U-MIDAS分位回归模型 bayES分析 嵌套Lasso惩罚
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两类损失函数下泊松差分布参数的Bayes估计
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作者 王德辉 李昕炎 《辽宁大学学报(自然科学版)》 2025年第1期86-96,共11页
本文研究在熵损失函数以及0-1损失函数下泊松差分布参数的Bayes估计问题.首先,以Bayes推断思想为基础,分别得出在两类损失函数下参数的Bayes估计.其次,通过随机模拟验证了两类损失函数下Bayes估计的相合性与渐近正态性,并且对这两类损... 本文研究在熵损失函数以及0-1损失函数下泊松差分布参数的Bayes估计问题.首先,以Bayes推断思想为基础,分别得出在两类损失函数下参数的Bayes估计.其次,通过随机模拟验证了两类损失函数下Bayes估计的相合性与渐近正态性,并且对这两类损失函数下的Bayes估计进行了比较.结果表明,两类损失函数下的Bayes估计均具有良好的估计效果,在相同样本下,熵损失函数下的Bayes估计要优于0-1损失函数下的Bayes估计.最后,利用泊松差分布对某医院每日使用床位数目的变化量进行实证分析,通过皮尔逊卡方检验,熵损失函数下的Bayes估计得到的泊松差分布与数据的拟合度较好. 展开更多
关键词 泊松差分布 bayES估计 熵损失函数 0-1损失函数 随机模拟
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Interlinked water and sediment microplastics in the Laizhou Bay of China
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作者 Hong CHEN Fenghua JIANG +5 位作者 Jingxi LI Wei CAO Di ZHANG Futao ZHANG Shiliang WANG Chengjun SUN 《Journal of Oceanology and Limnology》 2025年第2期446-458,共13页
To explore the relationship of microplastic pollution in different media in marine environment,microplastics in the surface seawater and sediments of Laizhou Bay,Bohai Sea,North China,were studied.Seawater samples wer... To explore the relationship of microplastic pollution in different media in marine environment,microplastics in the surface seawater and sediments of Laizhou Bay,Bohai Sea,North China,were studied.Seawater samples were collected using a pre-concentrator equipped with a 20-μm mesh size sieve,and sediment samples were collected by a box sampler.The shape,color,size,and type of microplastics were obtained by a stereomicroscope and a Fourier transform infrared spectrometer(ATR-μ-FT-IR).Results show that the abundance of microplastics in the surface seawater of Laizhou Bay was 858.3±573.2 items/m~3,and that of microplastics in sediments was 151.0±77.4 items/kg dry weight(d.w.)The microplastics in seawater and sediments were mainly fibrous.Meanwhile,the microplastics in seawater were mainly transparent,and those in sediments were transparent and blue.The highest proportion of microplastics in seawater was rayon(77.48%),followed by polyethylene terephthalate(PET,13.17%).The highest proportion of microplastics in sediments was rayon(73.66%),followed by PET(8.90%).The size of microplastics in 1000-2000μm accounted for the largest proportion of 28.54%in seawater,while that in 500-1000μm took 27.93%in sediment.Microplastics in seawater and sediment showed medium-level pollution.In seawater,microplastic abundance was higher in offshore and nearshore areas of Weifang.In sediment,microplastic abundance was higher in offshore and nearshore areas of Dongying.The results of the principal component analysis(PCA)indicated that microplastics in sediment exhibited greater stability compared to those in seawater.The microplastics in seawater and sediment show a positive correlation in terms of shape and plastic type,while exhibiting a negative correlation in terms of color.Overall,microplastics in sediments were smaller in size,and those in seawater and sediments had consistent size distribution characteristics in space. 展开更多
关键词 microplastic Laizhou bay SEDIMENT seawater CORRELATION
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Two New Species of Tricoma Cobb,1894(Nematoda:Desmoscolecidae)from the Continental Shelf of Bay of Bengal,India(Indian EEZ)
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作者 ANSARI Kapuli Gani Mohamed Thameemul MANOKARAN Seerangan +1 位作者 RAJA Sanjeeve BOUFAHJA Fehmi 《Journal of Ocean University of China》 2025年第4期1045-1057,共13页
Two new free-living marine nematode species belonging to the genus Tricoma Cobb,1894(Desmoscolecidae)are identi-fied from the continental shelf region of the Bay of Bengal.Tricoma ajmalia sp.nov.is characterized by th... Two new free-living marine nematode species belonging to the genus Tricoma Cobb,1894(Desmoscolecidae)are identi-fied from the continental shelf region of the Bay of Bengal.Tricoma ajmalia sp.nov.is characterized by the number of main rings(84 male and 85 female),the arrangement of somatic setae,the head shape with broadly truncated end,the relatively long cephalic setae(69%-73%of corresponding head diameter),the amphids extending up to second main ring,slender spicules slightly curved and gu-berbaculum with dorsocaudally directed apophyses.The second new species,Tricoma sampadansis sp.nov.is characterized by the number of rings(64),the arrangement of somatic setae(14-13 subdorsal,16 subvenral),the head shape with broadly truncated end,the relatively long cephalic setae(75%corresponding head diameter),the amphidial fovea extending over first main ring,anterioirly bent spicules and gubernaculum with hooked proximal end.An updated valid species list of Tricoma is also presented. 展开更多
关键词 marine nematodes Tricominae TAXONOMY morphology continental shelf bay of Bengal
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Long-term dynamics of net-phytoplankton community under environmental drivers in Jiaozhou Bay,China
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作者 Shimeng YANG Shujin GUO +3 位作者 Mingliang ZHU Yongfang ZHAO Shan ZHENG Xiaoxia SUN 《Journal of Oceanology and Limnology》 2025年第5期1477-1487,共11页
To better understand the spatial variations in phytoplankton abundance and community structure and their relationship with environmental parameters in Jiaozhou Bay,Yellow Sea,in Shandong,East China,observations were c... To better understand the spatial variations in phytoplankton abundance and community structure and their relationship with environmental parameters in Jiaozhou Bay,Yellow Sea,in Shandong,East China,observations were conducted to estimate abundance of net-phytoplankton and key groups along with environmental parameters in three typical sites in seasonal survey from 2004 to 2016 in the bay.The spatial patterns of phytoplankton abundance differed obviously between the inner and the outer bay.The abundance of total phytoplankton and diatoms increased obviously in the northern part of the bay,while decreased in the southern part and outer bay.An increase in dinoflagellate abundance was obvious in the outer bay.Variations in the dynamics of phytoplankton abundance could be largely explained by the succession of chain-forming diatoms and dinoflagellates.The key chain forming diatom groups Chaetoceros and Thalassiosira increased markedly,especially in winter in the northern part of the bay,while in the southern part and the outer bay,Chaetoceros declined.Besides,the key dinoflagellate groups Ceratium and Noctiluca increased noticeably,resulting in a significant increase in the dinoflagellate/diatom ratio in the outer bay.These variations has a significant correlation with environmental variables of surface seawater temperature,phosphorus,nitrogen,salinity,and N/Si ratio(P<0.05).For the key groups,temperature was the primary driver of dinoflagellate abundance,while the N/P ratio was critical for chain-forming diatoms.The abundance of phytoplankton showed a clear spatial pattern and associated obviously with environmental factors in the marine ecosystems,offering insights into coastal ecosystem management and conservation strategies. 展开更多
关键词 PHYTOPLANKTON ABUNDANCE long-term variation environmental factor Jiaozhou bay
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Tidal variability and microplastics distribution:source analysis in Dongshan Bay beach sediments,South China
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作者 A B M Sadique RAYHAN Jun WANG +4 位作者 Md Mazharul ISLAM Kazi Belayet HOSSAIN Bin CHEN Hongwei KE Minggang CAI 《Journal of Oceanology and Limnology》 2025年第2期459-473,共15页
Microplastic(MP)contamination is becoming a major worldwide concern,affecting terrestrial and aquatic ecosystems.This study investigated the source,distribution,and abundance of MPs in sediments from Dongshan Bay,Fuji... Microplastic(MP)contamination is becoming a major worldwide concern,affecting terrestrial and aquatic ecosystems.This study investigated the source,distribution,and abundance of MPs in sediments from Dongshan Bay,Fujian,South China,emphasizing particularly the coastline region's susceptibility to tidal impacts in four study sites.The concentrations of MPs in the sediments in the four sites were high from 7.4 to 283.1 items/kg(dry weight).There were notable differences in abundance between the locations and tide levels.Tides influenced the distribution of MPs greatly;however,the estuary areas showed greater MPs abundance during high tide,due possibly to enhanced water turbulence and riverine inputs.Low tide indicated higher concentrations in coastal locations owing to accumulation.Popular varieties,including nylon,polypropylene,and polyethylene,were identified by polymer research,pointing to the origins from fishing,packaging,and mariculture industries.Potential sources were determined using the PCA-K-means statistical analysis,by linking the origins of MPs to domestic activities,fishing,mariculturing,shipping,and packing.Fishing and packing were shown in the Sankey diagram as the two main sources,but their effects varied with research locations and tidal regimes.This study clarified the intricate dynamics of MPs pollution,highlighting the impact of tides on its dispersal and the variety of sources that contribute to this widespread environmental problem in coastal areas. 展开更多
关键词 microplastic(MP) TIDE source sediment Dongshan bay
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Current Population,Habitat Status and Species of Amphioxus in Dongshan Bay,Fujian Province
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作者 WENG Zhaohong XIE Yangjie +6 位作者 FANG Qi LI Jun LIU Jingwen WANG Jiaqiao HUANG Liangmin QU Tao XIE Wenliang 《Journal of Ocean University of China》 2025年第2期417-426,共10页
Dongshan Bay,along with Xiamen Bay,serves as a significant distribution area for amphioxus in Fujian Province.In this survey,we observed that the sedimentary environment of Dongshan Bay has been seriously silted due t... Dongshan Bay,along with Xiamen Bay,serves as a significant distribution area for amphioxus in Fujian Province.In this survey,we observed that the sedimentary environment of Dongshan Bay has been seriously silted due to rapid economic development and the thriving aquaculture industry.Consequently,there has been a significant reduction in suitable habitats for amphioxus and a sharp decline in its resource abundance.Totally 9 amphioxuses were collected from its eastern region in 2022 with a population density of 18.75 ind m^(-2) and a body length from 34.15 to 48.02 mm.The amphioxuses acquired in this investigation were classified as Branchiostoma japonicum based on morphological traits,such as a cuspate rostral fin,measurements of angles between the dorsal and super-caudal fins,angles between the pre-anal and sub-caudal fins,along with an accurate count of pre-anal fin chambers which matched those observed in B.japonicum.Moreover,a molecular barcoding analysis was conducted using a fragment of the mitochondrial COI gene.The results indicated that Branchiostoma sp.from Dongshan Bay in this study belongs to B.japonicum,providing additional support for the morphological identification results.Considering amphioxuses are still surviving in Dongshan Bay despite the destruction of their habitat,it is recommended to implement measures to safeguard their resources and habitats.The measures may include designating protection areas,strengthening law enforcement management to prohibit sand mining,regulating the scale of cage aquaculture,and augmenting wild resources through artificial breeding and release. 展开更多
关键词 AMPHIOXUS distribution species identification habitat status Dongshan bay
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Leveraging Bayesian methods for addressing multi-uncertainty in data-driven seismic liquefaction assessment
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作者 Zhihui Wang Roberto Cudmani +2 位作者 Andrés Alfonso Peña Olarte Chaozhe Zhang Pan Zhou 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第4期2474-2491,共18页
When assessing seismic liquefaction potential with data-driven models,addressing the uncertainties of establishing models,interpreting cone penetration tests(CPT)data and decision threshold is crucial for avoiding bia... When assessing seismic liquefaction potential with data-driven models,addressing the uncertainties of establishing models,interpreting cone penetration tests(CPT)data and decision threshold is crucial for avoiding biased data selection,ameliorating overconfident models,and being flexible to varying practical objectives,especially when the training and testing data are not identically distributed.A workflow characterized by leveraging Bayesian methodology was proposed to address these issues.Employing a Multi-Layer Perceptron(MLP)as the foundational model,this approach was benchmarked against empirical methods and advanced algorithms for its efficacy in simplicity,accuracy,and resistance to overfitting.The analysis revealed that,while MLP models optimized via maximum a posteriori algorithm suffices for straightforward scenarios,Bayesian neural networks showed great potential for preventing overfitting.Additionally,integrating decision thresholds through various evaluative principles offers insights for challenging decisions.Two case studies demonstrate the framework's capacity for nuanced interpretation of in situ data,employing a model committee for a detailed evaluation of liquefaction potential via Monte Carlo simulations and basic statistics.Overall,the proposed step-by-step workflow for analyzing seismic liquefaction incorporates multifold testing and real-world data validation,showing improved robustness against overfitting and greater versatility in addressing practical challenges.This research contributes to the seismic liquefaction assessment field by providing a structured,adaptable methodology for accurate and reliable analysis. 展开更多
关键词 Data-driven method bayes analysis Seismic liquefaction UNCERTAINTY Neural network
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Influence of grounding giant iceberg D15 on sea ice and polynyas in a sea ice-ice shelf-ocean numerical model of the Prydz Bay,Antarctica
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作者 Quanyi Zhou Jiuxin Shi +5 位作者 Chuning Wang Longjiang Mu Zhigang Yao Zhaoru Zhang Yuxin Han Yongming Sun 《Acta Oceanologica Sinica》 2025年第3期147-160,共14页
A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the ... A three-dimensional coupled sea ice-ice shelf-ocean numerical model is developed for the Prydz Bay,Antarctica,using the Regional Ocean Modeling System with a grid resolution of approximately 2 km.The influence of the grounding giant iceberg D15 on the distribution of sea ice and polynyas in the Prydz Bay is analyzed through two numerical experiments.Iceberg D15,grounded off the western edge of the West Ice Shelf(WIS),obstructs the southwestward transport of sea ice along the east coast of Prydz Bay,causing sea ice to accumulate to the east of the iceberg and form multi-year fast ice.Grounding of Iceberg D15 also decreases sea ice coverage off its south edge and creates ice-free openings in spring near Davis Station and Zhongshan Station,facilitating the accessibility of vessels to the research stations.These simulated sea ice patterns closely match current satellite observations.When Iceberg D15 is removed,the previously blocked sea ice north of the iceberg,which moved westward,shifts southwesterly along the coastline,leading to a reduction in sea ice thickness during winter and spring,as well as lower sea ice concentrations in spring across large areas north and west of the iceberg.In contrast,the sea ice thickness increases considerably southwest of the WIS,extending to the front of the Amery Ice Shelf during seasons covered by sea ice.The increase in sea ice concentration can also extend to as far as 75°E in spring.Without Iceberg D15,which previously contributed to the ice barrier of Barrier Polynya(BP),the shape of BP changes,the area of BP and Davis Polynya(DP)decreases,and the polynya off the northwest edge of the WIS near 83°E expands.These polynya patterns are much similar to the satellite remote sensing observations before Iceberg D15 was grounded.From April to October,the total area of BP and DP decreases by 2.83×10^(4)km^(2)(60%)and 2.20×10^(3)km^(2)(20%),respectively,while the total sea ice production decreases by 4.11×10^(10)m^(3)(66%)and 1.52×10^(10)m^(3)(52%)compared to the experiment with iceberg.These results indicate the substantial effects of grounding giant icebergs on the spatio-temporal distribution of sea ice,the area of polynyas,and sea ice production.High-resolution Antarctic coastal numerical models,typically with grid scales of kilometers,are sufficient to represent large icebergs,and adding the grounding giant icebergs is crucial for producing realistic simulations of sea ice and polynyas. 展开更多
关键词 grounding iceberg sea ice POLYNYA numerical simulation Prydz bay ANTARCTICA
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