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Prompt reverse learning:enhancing visual language models for medical image recognition
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作者 Shuhan Zhu Yonggang Zhang Xinmei Tian 《Journal of University of Science and Technology of China》 北大核心 2026年第1期23-33,I0001,共12页
Large visual language models such as CLIP have demonstrated impressive performance on various downstream tasks involving natural images,by leveraging prompt learning.However,these models often falter when applied to t... Large visual language models such as CLIP have demonstrated impressive performance on various downstream tasks involving natural images,by leveraging prompt learning.However,these models often falter when applied to tasks involving medical images.We provide an experimental insight into this phenomenon:CLIP is insensitive to the class names of medical images.For instance,replacing the class name“medulloblastoma”(a type of brain tumor)with“dog”in prompts has minimal impact on performance,a phenomenon not observed with natural images.To realign prompt learning with medical image recognition,we propose a novel prompt learning strategy,termed prompt reverse learning(PeLen).Different from the existing methods that adapt CLIP’s representations to downstream tasks,PeLen adapts task-specific representations to CLIP’s representations.Built upon the insensitivity to the class names of medical images,PeLen designates natural images and their class names to represent a specific class of medical images and class names,e.g.,allowing the image and text of a dog to correspond to the image and text of medulloblastoma.Consequently,PeLen learns prompts to align the representations between the medical images and the visual and textual representations of natural images.Our experiments demonstrate the efficacy of PeLen for medical image recognition. 展开更多
关键词 prompt learning image recognition visual language model
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Agri-Eval:Multi-level Large Language Model Valuation Benchmark for Agriculture
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作者 WANG Yaojun GE Mingliang +2 位作者 XU Guowei ZHANG Qiyu BIE Yuhui 《农业机械学报》 北大核心 2026年第1期290-299,共10页
Model evaluation using benchmark datasets is an important method to measure the capability of large language models(LLMs)in specific domains,and it is mainly used to assess the knowledge and reasoning abilities of LLM... Model evaluation using benchmark datasets is an important method to measure the capability of large language models(LLMs)in specific domains,and it is mainly used to assess the knowledge and reasoning abilities of LLMs.Therefore,in order to better assess the capability of LLMs in the agricultural domain,Agri-Eval was proposed as a benchmark for assessing the knowledge and reasoning ability of LLMs in agriculture.The assessment dataset used in Agri-Eval covered seven major disciplines in the agricultural domain:crop science,horticulture,plant protection,animal husbandry,forest science,aquaculture science,and grass science,and contained a total of 2283 questions.Among domestic general-purpose LLMs,DeepSeek R1 performed best with an accuracy rate of 75.49%.In the realm of international general-purpose LLMs,Gemini 2.0 pro exp 0205 standed out as the top performer,achieving an accuracy rate of 74.28%.As an LLMs in agriculture vertical,Shennong V2.0 outperformed all the LLMs in China,and the answer accuracy rate of agricultural knowledge exceeded that of all the existing general-purpose LLMs.The launch of Agri-Eval helped the LLM developers to comprehensively evaluate the model's capability in the field of agriculture through a variety of tasks and tests to promote the development of the LLMs in the field of agriculture. 展开更多
关键词 large language models assessment systems agricultural knowledge agricultural datasets
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Ecological Dynamics of a Logistic Population Model with Impulsive Age-selective Harvesting
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作者 DAI Xiangjun JIAO Jianjun 《应用数学》 北大核心 2026年第1期72-79,共8页
In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asy... In this paper,we establish and study a single-species logistic model with impulsive age-selective harvesting.First,we prove the ultimate boundedness of the solutions of the system.Then,we obtain conditions for the asymptotic stability of the trivial solution and the positive periodic solution.Finally,numerical simulations are presented to validate our results.Our results show that age-selective harvesting is more conducive to sustainable population survival than non-age-selective harvesting. 展开更多
关键词 The logistic population model Selective harvesting Asymptotic stability EXTINCTION
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Peak separation and small-signal modeling analysis of abnormal shift in the transconductance curve in InAs composite channel HEMT
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作者 GONG Yong-Heng CHEN Yu-Xuan +5 位作者 SHI Jing-Yuan ZHANG Da-Yong SU Yong-Bo DING Wu-Chang DING Peng JIN Zhi 《红外与毫米波学报》 北大核心 2026年第2期270-278,共9页
In this work,100 nm gate-length InP-based high electron mobility transistors(HEMTs)with a composite InGaAs/InAs/InGaAs channel are fabricated.DC measurements indicate that the InAs channel enhances transconductance bu... In this work,100 nm gate-length InP-based high electron mobility transistors(HEMTs)with a composite InGaAs/InAs/InGaAs channel are fabricated.DC measurements indicate that the InAs channel enhances transconductance but shifts the peak point toward lower V_(gs) under high V_(ds) bias.Peak separation analysis reveals the DC transconductance curve is composed of two components:the gate-controlled transconductance and the impact-ionization-induced additional transconductance.Further analysis demonstrates that the anomalous shift originates from the channel impact ionization intensity variation,which is caused by changes in the gate-drain electric field rather than the carrier density in the channel.Two additional current sources are introduced in the small-signal model to characterize the impact-ionization-induced transconductance,and the numerical variation trends of their parameters are consistent with the peak separation results,which validate the mechanism's correctness.RF measurements confirm that the DC transconductance enhancement does not effectively improve RF characteristics,which is attributed to the ionization-induced transconductance having a time constant significantly larger than that of conventional transconductance components.These findings provide a theoretical foundation for controlling the impact-ionization. 展开更多
关键词 HEMTS INAS peak separation impact ionization TRANSCONDUCTANCE small-signal equivalent model
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Efficient Model Reduction of Linear Time-varying Systems via Shifted Legendre Polynomial Approximations
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作者 XIAO Zhihua TANG Man ZHU Zhihui 《应用数学》 北大核心 2026年第2期481-493,共13页
This paper presents an efficient model reduction technique for linear time-varying systems based on shifted Legendre polynomials.The approach constructs approximate low-rank decomposition factors of finite-time Gramia... This paper presents an efficient model reduction technique for linear time-varying systems based on shifted Legendre polynomials.The approach constructs approximate low-rank decomposition factors of finite-time Gramians directly from the expansion coefficients of impulse responses.Leveraging these factors,we develop two model reduction algorithms that integrate the low-rank square root method with dominant subspace projection.Our method is computationally efficient and flexible,requiring only a few matrix-vector operations and a singular value decomposition of a low-dimensional matrix,thereby avoiding the need to solve differential Lyapunov equations.Numerical experiments confirm the effectiveness of the proposed approach. 展开更多
关键词 model reduction Time-varying systems Low-rank Gramians Balanced truncation Shifted Legendre polynomials
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Learning Performance of Nonlinear Classification Models Based on Markov Sampling
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作者 HU Shulan WANG Yusheng +1 位作者 QIAN Zhiyong WANG Renhe 《应用概率统计》 北大核心 2026年第1期61-74,共14页
Nonlinear classification models are widely used in various fields due to their excellent performance in handling complex problems.This paper investigates the learning performance of nonlinear classification models bas... Nonlinear classification models are widely used in various fields due to their excellent performance in handling complex problems.This paper investigates the learning performance of nonlinear classification models based on Markov sampling,which builds upon the traditional framework using i.i.d.samples.Subsequently,we introduce a ueMC-NL algorithm,tailored specifically for nonlinear classification models,facilitating the production of ueMC samples from a finite dataset.Numerical investigations on the random forest and the MLP model reveal that nonlinear classification models utilizing ueMC samples yield lower misclassification rates compared to i.i.d.samples. 展开更多
关键词 learning performance Markov sampling nonlinear classification models uniformly ergodic Markov chain
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Modeling of Penicillin Fermentation Process Based on a Multi-stage LHS-EPRCC Method
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作者 Li Quan Su Peng +5 位作者 Wan Haiying Zhang Chengxi He Zhijian Ni Yiyang Zhao Zhonggai Liu Fei 《系统仿真学报》 北大核心 2026年第5期1255-1276,共22页
This paper focused on the modeling of microbial fermentation processes under varying production environments and proposed a novel approach.Considering that the dynamic characteristics of microorganisms differ across g... This paper focused on the modeling of microbial fermentation processes under varying production environments and proposed a novel approach.Considering that the dynamic characteristics of microorganisms differ across growth stages,we introduced the concept of multi-stage sensitivity analysis,in which each stage was investigated separately.The fuzzy C-means(FCM)algorithm was employed to cluster process data under nominal conditions,thereby dividing the penicillin fermentation process into distinct growth stages.Based on this division,the Latin hypercube sampling with partial rank correlation coefficient(LHS-EPRCC)method was applied to conduct sensitivity analysis for each stage,identifying an importance parameter set(IPS)that corresponds to the stage-specific growth characteristics.Re-estimation and correction of the IPS were then performed to enhance the predictive accuracy of the model.In a penicillin fermentation process deviating from nominal conditions,the proposed method was applied for model correction.Simulation results demonstrate that the corrected model aligns well with the actual process,thereby verifying the effectiveness of the proposed multistage sensitivity analysis approach in addressing complex fermentation processes and environmental uncertainties. 展开更多
关键词 penicillin fermentation process FCM algorithm LHS-EPRCC method importance parameter set model correction
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Design optimization and FEA of B-6 and B-7 levels ballistics armor:A modelling approach
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作者 Muhammad Naveed CHU Jinkui +1 位作者 Atif Ur Rehman Arsalan Hyder 《大连理工大学学报》 北大核心 2026年第1期66-77,共12页
Utilizing finite element analysis,the ballistic protection provided by a combination of perforated D-shaped and base armor plates,collectively referred to as radiator armor,is evaluated.ANSYS Explicit Dynamics is empl... Utilizing finite element analysis,the ballistic protection provided by a combination of perforated D-shaped and base armor plates,collectively referred to as radiator armor,is evaluated.ANSYS Explicit Dynamics is employed to simulate the ballistic impact of 7.62 mm armor-piercing projectiles on Aluminum AA5083-H116 and Steel Secure 500 armors,focusing on the evaluation of material deformation and penetration resistance at varying impact points.While the D-shaped armor plate is penetrated by the armor-piercing projectiles,the combination of the perforated D-shaped and base armor plates successfully halts penetration.A numerical model based on the finite element method is developed using software such as SolidWorks and ANSYS to analyze the interaction between radiator armor and bullet.The perforated design of radiator armor is to maintain airflow for radiator function,with hole sizes smaller than the bullet core diameter to protect radiator assemblies.Predictions are made regarding the brittle fracture resulting from the projectile core′s bending due to asymmetric impact,and the resulting fragments failed to penetrate the perforated base armor plate.Craters are formed on the surface of the perforated D-shaped armor plate due to the impact of projectile fragments.The numerical model accurately predicts hole growth and projectile penetration upon impact with the armor,demonstrating effective protection of the radiator assemblies by the radiator armor. 展开更多
关键词 radiator armor ballistics simulation Johnson-Cook model armor-piercing projectile perforated D-shaped armor plate
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Pathogenesis Reasoning Chain-of-thought Supervision for Large Language Models:Syndrome Manifestation Recognition and Multidimensional Evaluation in Spleen-stomach Disorders
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作者 YANG Shu-Han HU Yu-Xin +3 位作者 YU Xin-Yu TU Yu-Ying ZANG Yi-Chang LI Pan-Fei 《生物化学与生物物理进展》 北大核心 2026年第5期1240-1263,共24页
Objective The essence of syndrome manifestation recognition in traditional Chinese medicine(TCM)is to infer the body’s latent pathogenesis state from clinical observational information,rather than to perform simple l... Objective The essence of syndrome manifestation recognition in traditional Chinese medicine(TCM)is to infer the body’s latent pathogenesis state from clinical observational information,rather than to perform simple label matching.However,previous studies have largely modeled this task as syndrome pattern classification within a fixed label space,which does not adequately reflect the cognition process of TCM syndrome differentiation centered on pathogenesis reasoning,and is also insufficient to capture the openness,semantic variability,and cross-disease reusability of syndrome manifestation expression.This study aimed to investigate whether introducing pathogenesis reasoning chain-of-thought(PR-CoT)supervision into large language models(LLMs)could improve the quality and cognitive consistency of syndrome manifestation recognition and support cross-disease transfer.Methods Syndrome manifestation recognition was formulated as a conditional generation task under the framework of clinical observational information(X)→pathogenesis structure(Z)→syndrome pattern output(Y),where Z serves as an explicit intermediate structural variable linking the clinical evidence and syndrome judgment.Within this framework,a PR-CoT-supervised dataset for syndrome manifestation recognition was constructed based on medical case records of spleen-stomach disorders.After preprocessing,information extraction,manual proofreading,and data cleaning,the dataset comprised 4800 training cases,400 development cases,and 400 test cases.Each sample was annotated with a structured PR-CoT consisting of three progressive levels:clinical information summarization,comprehensive pathogenesis analysis,and syndrome pattern output.Supervised fine-tuning was conducted on open-source LLMs,with an end-to-end model serving as the baseline.Qwen3-32B was used as the primary experimental model,and Qwen3-14B as the scale comparison model.A progressive multidimensional evaluation framework was further established,comprising a structural parsing level,a semantic similarity level,and an expert blind review level.At the structural parsing level,syndrome pattern expressions were decomposed into structural elements and evaluated using Precision,Recall,F1 score,and Jaccard similarity.At the semantic similarity level,independent LLMs scored the theoretical proximity between predicted and reference syndrome patterns.At the expert blind review level,three TCM experts independently evaluated model outputs on two dimensions:syndrome differentiation consistency and terminology standardization of syndrome patterns.In addition,zero-shot cross-disease transfer evaluation was conducted on gynecological and heart-system disorder test sets.Results At the structural parsing level,PR-CoT supervision did not lead to a stable improvement in the element-wise overlap of syndrome pattern structural components.Compared with the corresponding baselines,neither Qwen3-32B nor Qwen3-14B showed consistent advantages in structural matching metrics after the introduction of PR-CoT supervision.In contrast,at the semantic similarity level,PR-CoT supervision produced stable positive gains across different model scales and evaluation systems.The average semantic score of Qwen3-32B increased from 6.4258 in the baseline model to 6.5850 after PR-CoT supervision,and that of Qwen3-14B increased from 5.8700 to 5.9642.At the expert blind review level,the overall score of Qwen3-32B(PR-CoT)was 7.0260±0.1077,higher than 6.4163±0.2889 for its baseline.In zero-shot cross-disease testing,the PR-CoT model still showed advantages in semantic evaluation and expert evaluation on both gynecological and heart-system disorder test sets,indicating a certain degree of transferability.Conclusion The benefits of PR-CoT supervision are mainly reflected in TCM semantic consistency and clinical plausibility,rather than in improved hard matching of structural elements.These findings support understanding syndrome manifestation recognition as a process of generating and expressing latent pathogenesis structures,rather than as a classification task within a traditional fixed label space.By introducing pathogenesis reasoning as an explicit intermediate structure into the modeling process and combining it with a progressive multidimensional evaluation framework,this study provides a methodological pathway for intelligent TCM syndrome differentiation that integrates theoretical alignment,interpretability,and multi-level evaluation. 展开更多
关键词 traditional Chinese medicine syndrome manifestation recognition large language models chain-of-thought syndrome pattern evaluation spleen-stomach disorders
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Command-agent:Reconstructing warfare simulation and command decision-making using large language models
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作者 Mengwei Zhang Minchi Kuang +3 位作者 Heng Shi Jihong Zhu Jingyu Zhu Xiao Jiang 《Defence Technology(防务技术)》 2026年第2期294-313,共20页
War rehearsals have become increasingly important in national security due to the growing complexity of international affairs.However,traditional rehearsal methods,such as military chess simulations,are inefficient an... War rehearsals have become increasingly important in national security due to the growing complexity of international affairs.However,traditional rehearsal methods,such as military chess simulations,are inefficient and inflexible,with particularly pronounced limitations in command and decision-making.The overwhelming volume of information and high decision complexity hinder the realization of autonomous and agile command and control.To address this challenge,an intelligent warfare simulation framework named Command-Agent is proposed,which deeply integrates large language models(LLMs)with digital twin battlefields.By constructing a highly realistic battlefield environment through real-time simulation and multi-source data fusion,the natural language interaction capabilities of LLMs are leveraged to lower the command threshold and to enable autonomous command through the Observe-Orient-Decide-Act(OODA)feedback loop.Within the Command-Agent framework,a multimodel collaborative architecture is further adopted to decouple the decision-generation and command-execution functions of LLMs.By combining specialized models such as Deep Seek-R1 and MCTool,the limitations of single-model capabilities are overcome.MCTool is a lightweight execution model fine-tuned for military Function Calling tasks.The framework also introduces a Vector Knowledge Base to mitigate hallucinations commonly exhibited by LLMs.Experimental results demonstrate that Command-Agent not only enables natural language-driven simulation and control but also deeply understands commander intent.Leveraging the multi-model collaborative architecture,during red-blue UAV confrontations involving 2 to 8 UAVs,the integrated score is improved by an average of 41.8%compared to the single-agent system(MCTool),accompanied by a 161.8%optimization in the battle loss ratio.Furthermore,when compared with multi-agent systems lacking the knowledge base,the inclusion of the Vector Knowledge Base further improves overall performance by 16.8%.In comparison with the general model(Qwen2.5-7B),the fine-tuned MCTool leads by 5%in execution efficiency.Therefore,the proposed Command-Agent introduces a novel perspective to the military command system and offers a feasible solution for intelligent battlefield decision-making. 展开更多
关键词 Digital twin battlefield Large language models Multi-agent system Military command
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Rock-concrete composite specimens with different interface inclination angles:Creep characteristics and nonlinear damage constitutive model
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作者 YAO Wei-jing NOUBISSI KENGNE Honorine +2 位作者 LIU Yu PANG Jian-yong XU Han-bing 《Journal of Central South University》 2026年第2期968-986,共19页
Weak rock-concrete interfaces significantly affect the stability of underground supporting structures.This study aims to investigate the effects of interface inclination on the creep behavior and failure mechanisms of... Weak rock-concrete interfaces significantly affect the stability of underground supporting structures.This study aims to investigate the effects of interface inclination on the creep behavior and failure mechanisms of composite specimens.Seven rock-concrete composite specimens with different inclination angles under hydrothermal curing at 60℃were prepared,and uniaxial and graded loading creep tests were completed.The results show that with increasing interface inclination,the compressive strength of the composite specimens initially decreases and then increases,with the minimum strength observed at inclinations between 60°and 75°.Three typical failure patterns were identified:axial failure,composite failure,and interface failure.The creep failure strength exceeded the uniaxial compressive strength,indicating improved time-dependent deformation resistance under elevated temperature curing.The instantaneous strain initially decreases and then increases as the interface inclination angle grows.Compared to 0°inclination,specimens with 45°,60°,75°,and 90°inclinations exhibited reductions in instantaneous strain of 2.64%,18.84%,23.29%,and 0.73%,respectively.The steady-state creep rate and creep ratio exhibited a decrease-stabilization-increase trend with increasing stress levels.Creep strain increased with increasing stress levels for all inclinations,with a sharp increase near the failure stage.A nonlinear constitutive model considering interface inclination and creep damage was developed based on damage theory.A nonlinear damage-based constitutive model incorporating interface inclination effects was developed,and its theoretical predictions closely matched the experimental data in all creep stages.These findings provide a quantitative understanding of creep failure mechanisms in rock-concrete interfaces and provide practical references for enhancing the safety of underground support systems. 展开更多
关键词 rock-concrete composite interface inclination stress level CREEP nonlinear damage model
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A Model-based Method Deployed on Smartphones for Evaluating Hardness and Anthocyanin Content of Blue Honeysuckle Berry
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作者 Zheng Xianzhe Jiang Zhenze +4 位作者 Xue Liangliang Zhang Yuhan Bai Caiyu Liu Huiran Cong Hongyue 《Journal of Northeast Agricultural University(English Edition)》 2026年第1期71-87,共17页
A machine learning-based APP may quickly and non-destructively evaluate the quality of parameters,such as hardness and anthocyanin content in blue honeysuckle berries(Lonicera caerulea L.,BHB),based on changes in peri... A machine learning-based APP may quickly and non-destructively evaluate the quality of parameters,such as hardness and anthocyanin content in blue honeysuckle berries(Lonicera caerulea L.,BHB),based on changes in pericarp color characteristics.The color feature information of the BHB pericarp was extracted,and the corresponding hardness and anthocyanin content were determined at various growing stages.Correlation analysis of BHB quality indexes was conducted by single and combined components of BHB epidermal color features.The results showed that fruit hardness had a significantly negative correlation with color feature parameter R-G,and its anthocyanin content had a significantly positive correlation with color feature parameter R.Comparing the eight models,random forest(RF)was established to evaluate the hardness and anthocyanin content of BHB according to the correlation between pericarp color features and hardness and anthocyanin content on BHB quality evaluation APP on the WeChat platform.The credibility of APP embedding RF model for evaluating hardness and anthocyanin content in BHB was validated with the determination coefficient of 0.89 and 0.93 in practice.This approach could efficiently and conveniently evaluate the quality indexes of BHB in real time and serve as a technical reference for the detection of quality indicators of other berries using smartphones. 展开更多
关键词 WeChat APP blue honeysuckle berry anthocyanins quality evaluation random forest model
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Two-phase pairwise comparison-based model for the ranking prediction of global innovation capability
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作者 CUI Ruijing SUN Jianbin YANG Kewei 《Journal of Systems Engineering and Electronics》 2026年第2期504-520,共17页
To predict the ranking of the country’s innovation capability in the world in real-time,this study designs a twophased prediction model based on the pairwise comparison.Data from the global innovation index(GII)repor... To predict the ranking of the country’s innovation capability in the world in real-time,this study designs a twophased prediction model based on the pairwise comparison.Data from the global innovation index(GII)reports are employed in this study.Countries with different income levels have shown different development inertias,the two-phased prediction model is thus proposed.In the first phase,the GII data from the previous year are applied to predict the ranking of innovation capability for high-income countries.In the second phase,more years of historical data are adopted to predict the innovation ranking for other countries.The global innovation rankings for all countries and economies are thus obtained.Experiments have proved that the model requires only a few indicators to get accurate results.The model provides real-time decision support for decision-makers to formulate innovative development policies. 展开更多
关键词 global innovation index(GII) pairwise comparison ranking prediction two-phased model
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基于TOPMODEL-LSTM耦合模型的安墩水流域洪水模拟研究
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作者 张慧文 解河海 +3 位作者 莫李娟 杨一彬 吴仁达 鞠琴 《节水灌溉》 北大核心 2026年第3期63-69,共7页
针对长短期记忆(LSTM)神经网络模型难以融合流域物理特征的问题,提出了TOPMODEL-LSTM耦合模型,基于安墩水流域2008-2018年水文数据,对比分析了3种输入方案下1~6 h预见期的径流模拟性能。结果表明:(1)耦合模型在各预见期下的预报精度均优... 针对长短期记忆(LSTM)神经网络模型难以融合流域物理特征的问题,提出了TOPMODEL-LSTM耦合模型,基于安墩水流域2008-2018年水文数据,对比分析了3种输入方案下1~6 h预见期的径流模拟性能。结果表明:(1)耦合模型在各预见期下的预报精度均优于LSTM模型,其中RMSE值平均降幅15%,MAE值平均降幅13%,R2由0.78提升至0.83,在一定程度上提升了洪水模拟精度;(2)在流域水文过程模拟中,采用逐时降水数据与同期径流量观测值联合作为模型基础输入数据的方案,经多组对比试验验证,其模拟精度显著优于单一径流输入或其他组合输入方案;(3)随着预见期延长,所有模型及其方案的模拟精度均出现下降,但耦合模型有效缓解了LSTM模型的记忆衰减问题,表现出更稳定的模拟性能。研究结果可为传统洪水模拟模型与人工智能模型的耦合建模提供技术参考。 展开更多
关键词 洪水模拟 TOPmodel-LSTM耦合模型 LSTM模型 预见期 安墩水流域
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基于简化E-Model的IP网络语音质量在线评估模型
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作者 赵展 雒江涛 +3 位作者 刘子实 杨砚 邹文波 周安通 《声学技术》 北大核心 2026年第1期100-109,共10页
语音质量检测是实时语音通信领域的研究重点。针对当前语音质量检测模型存在计算所需参数复杂、算法不开源等问题,文章提出了一种基于经典E-Model的语音质量在线检测模型。通过构建编码损伤、丢包损伤、时延损伤模型,对IP网络中的语音... 语音质量检测是实时语音通信领域的研究重点。针对当前语音质量检测模型存在计算所需参数复杂、算法不开源等问题,文章提出了一种基于经典E-Model的语音质量在线检测模型。通过构建编码损伤、丢包损伤、时延损伤模型,对IP网络中的语音传输损伤进行建模,并采用主观语音质量评估和回归分析方法推导出语音编码的语音质量预测公式。以Opus、iLBC语音编码为例,使用上述模型建立了用于预测Opus、iLBC语音编码的语音质量公式。实验结果表明,文章所提方法有效地拟合了主观听力模型,将E-Model的应用范围扩展到了全频带,并支持可变比特率的IP语音编码语音质量在线评估,为提升IP语音服务系统抗弱网能力提供了有力支持。 展开更多
关键词 语音质量在线检测 E-model 平均意见得分
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基于24Model的动火作业事故致因文本挖掘 被引量:1
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作者 牛茂辉 李威君 +1 位作者 刘音 王璐 《中国安全科学学报》 北大核心 2025年第3期151-158,共8页
为探究工业动火作业事故的根源,提出一种基于“2-4”模型(24Model)的文本挖掘方法。首先,收集整理220篇动火作业事故报告,并作为数据集,构建基于来自变换器的双向编码器表征量(BERT)的24Model分类器,使用预训练模型训练和评估事故报告... 为探究工业动火作业事故的根源,提出一种基于“2-4”模型(24Model)的文本挖掘方法。首先,收集整理220篇动火作业事故报告,并作为数据集,构建基于来自变换器的双向编码器表征量(BERT)的24Model分类器,使用预训练模型训练和评估事故报告数据集,构建分类模型;然后,通过基于BERT的关键字提取算法(KeyBERT)和词频-逆文档频率(TF-IDF)算法的组合权重,结合24Model框架,建立动火作业事故文本关键词指标体系;最后,通过文本挖掘关键词之间的网络共现关系,分析得到事故致因之间的相互关联。结果显示,基于BERT的24Model分类器模型能够系统准确地判定动火作业事故致因类别,通过组合权重筛选得到4个层级关键词指标体系,其中安全管理体系的权重最大,结合共现网络分析得到动火作业事故的7项关键致因。 展开更多
关键词 “2-4”模型(24model) 动火作业 事故致因 文本挖掘 指标体系
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Modeling and sliding mode control based on inverse compensation of piezo-positioning system 被引量:6
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作者 LI Zhi-bin XIN Yuan-ze +1 位作者 ZHANG Jian-qiang SUN Chong-shang 《中国光学(中英文)》 北大核心 2025年第1期170-185,共16页
In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis... In order to enhance the control performance of piezo-positioning system,the influence of hysteresis characteristics and its compensation method are studied.Hammerstein model is used to represent the dynamic hysteresis nonlinear characteristics of piezo-positioning actuator.The static nonlinear part and dynamic linear part of the Hammerstein model are represented by models obtained through the Prandtl-Ishlinskii(PI)model and Hankel matrix system identification method,respectively.This model demonstrates good generalization capability for typical input frequencies below 200 Hz.A sliding mode inverse compensation tracking control strategy based on P-I inverse model and integral augmentation is proposed.Experimental results show that compared with PID inverse compensation control and sliding mode control without inverse compensation,the sliding mode inverse compensation control has a more ideal step response and no overshoot,moreover,the settling time is only 6.2 ms.In the frequency domain,the system closed-loop tracking bandwidth reaches 119.9 Hz,and the disturbance rejection bandwidth reaches 86.2 Hz.The proposed control strategy can effectively compensate the hysteresis nonlinearity,and improve the tracking accuracy and antidisturbance capability of piezo-positioning system. 展开更多
关键词 piezo-positioning system hysteresis nonlinearity Hammerstein model Prandtl-Ishlinskii(P-I)model system identification sliding mode control
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Comparative study on the oblique water-entry of high-speed projectile based on rigid-body and elastic-plastic body model 被引量:2
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作者 Xiangyan Liu Xiaowei Cai +3 位作者 Zhengui Huang Yu Hou Jian Qin Zhihua Chen 《Defence Technology(防务技术)》 2025年第4期133-155,共23页
To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conduc... To examine the similarities and differences in the evolution of cavity,wetting and dynamics of a highspeed,oblique water-entry projectile with different positive angles of attack,a comparative analysis has been conducted based on the numerical results of two mathematical models,the rigid-body model and fluid-structure interaction model.In addition,the applicable scope of the above two methods,and the structural response characteristics of the projectile have also been investigated.Our results demonstrate that:(1) The impact loads and angular motion of the projectile of the rigid-body method are more likely to exhibit periodic variations due to the periodic tail slap,its range of positive angles of attack is about α<2°.(2) When the projectile undergone significant wetting,a strong coupling effect is observed among wetting,structural deformation,and projectile motion.With the applied projectile shape,it is observed that,when the projectile bends,the final wetting position is that of Part B(cylinder of body).With the occu rrence of this phenomenon,the projectile ballistics beco me completely unstable.(3) The force exerted on the lower surface of the projectile induced by wetting is the primary reason of the destabilization of the projectile traj ectory and structu ral deformation failure.Bending deformation is most likely to appear at the junction of Part C(cone of body) and Part D(tail).The safe angles of attack of the projectile stability are found to be about α≤2°. 展开更多
关键词 Fluid-structure interaction Rigid-body model Elastic-plastic model Structural deformation Impact loads Structural safety of projectile
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Failure microscopic mechanism and damage constitutive model of dolomite under water-rock coupling interaction 被引量:3
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作者 SUN Xiao-ming ZHANG Jing +6 位作者 SHI Fu-kun HE Lin-sen ZHANG Yong MIAO Cheng-yu DING Jia-xu MA Li-sha ZHAO Hao-ze 《Journal of Central South University》 2025年第4期1431-1446,共16页
To investigate the effects of water and cyclic loading on dolomite’s mechanical properties during deep mining,mechanical experiments on non-pressure water absorption and cyclic loading were conducted.The findings rev... To investigate the effects of water and cyclic loading on dolomite’s mechanical properties during deep mining,mechanical experiments on non-pressure water absorption and cyclic loading were conducted.The findings reveal that the elastic modulus and Poisson ratio of dolomite fluctuate with increasing water content.The mass of water absorption is positively correlated with time and the water absorption stage can be divided into three stages:accelerated,decelerated,and stabilized stages.During this process,the number of pores in dolomite increases,while the pore diameter initially decreases and then fluctuates.Microscopic analysis shows that the proportion of mesopores first increases and then decreases,while micropores exhibit the opposite trend,and the proportion of macropores fluctuates around 0%.A model diagram of structural evolution during water absorption has been developed.Additionally,the softening process of dolomite’s water absorption strength is categorized into three stages:a relatively stable stage,an accelerated softening stage dominated by mesopore water absorption,and a decelerated softening stage characterized by micropore water absorption.A uniaxial damage constitutive model for dolomite under water influence was established based on the Weibull distribution and Mohr-Coulomb strength criterion,and experimental validation indicates its strong applicability. 展开更多
关键词 water-rock coupling DOLOMITE constitutive model MICROSTRUCTURE loading-unloading cycle
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Intelligent modeling method for OV models in DoDAF2.0 based on knowledge graph 被引量:1
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作者 ZHANG Yue JIANG Jiang +3 位作者 YANG Kewei WANG Xingliang XU Chi LI Minghao 《Journal of Systems Engineering and Electronics》 2025年第1期139-154,共16页
Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a vi... Architecture framework has become an effective method recently to describe the system of systems(SoS)architecture,such as the United States(US)Department of Defense Architecture Framework Version 2.0(DoDAF2.0).As a viewpoint in DoDAF2.0,the operational viewpoint(OV)describes operational activities,nodes,and resource flows.The OV models are important for SoS architecture development.However,as the SoS complexity increases,constructing OV models with traditional methods exposes shortcomings,such as inefficient data collection and low modeling standards.Therefore,we propose an intelligent modeling method for five OV models,including operational resource flow OV-2,organizational relationships OV-4,operational activity hierarchy OV-5a,operational activities model OV-5b,and operational activity sequences OV-6c.The main idea of the method is to extract OV architecture data from text and generate interoperable OV models.First,we construct the OV meta model based on the DoDAF2.0 meta model(DM2).Second,OV architecture named entities is recognized from text based on the bidirectional long short-term memory and conditional random field(BiLSTM-CRF)model.And OV architecture relationships are collected with relationship extraction rules.Finally,we define the generation rules for OV models and develop an OV modeling tool.We use unmanned surface vehicles(USV)swarm target defense SoS architecture as a case to verify the feasibility and effectiveness of the intelligent modeling method. 展开更多
关键词 system of systems(SoS)architecture operational viewpoint(OV)model meta model bidirectional long short-term memory and conditional random field(BiLSTM-CRF) model generation systems modeling language
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