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Empowering Sentiment Analysis in Resource-Constrained Environments:Leveraging Lightweight Pre-trained Models for Optimal Performance
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作者 V.Prema V.Elavazhahan 《Journal of Harbin Institute of Technology(New Series)》 2025年第1期76-84,共9页
Sentiment analysis,a cornerstone of natural language processing,has witnessed remarkable advancements driven by deep learning models which demonstrated impressive accuracy in discerning sentiment from text across vari... Sentiment analysis,a cornerstone of natural language processing,has witnessed remarkable advancements driven by deep learning models which demonstrated impressive accuracy in discerning sentiment from text across various domains.However,the deployment of such models in resource-constrained environments presents a unique set of challenges that require innovative solutions.Resource-constrained environments encompass scenarios where computing resources,memory,and energy availability are restricted.To empower sentiment analysis in resource-constrained environments,we address the crucial need by leveraging lightweight pre-trained models.These models,derived from popular architectures such as DistilBERT,MobileBERT,ALBERT,TinyBERT,ELECTRA,and SqueezeBERT,offer a promising solution to the resource limitations imposed by these environments.By distilling the knowledge from larger models into smaller ones and employing various optimization techniques,these lightweight models aim to strike a balance between performance and resource efficiency.This paper endeavors to explore the performance of multiple lightweight pre-trained models in sentiment analysis tasks specific to such environments and provide insights into their viability for practical deployment. 展开更多
关键词 sentiment analysis light weight models resource⁃constrained environment pre⁃trained models
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The ρ-Meson Electromagnetic Form Factors within the Light-Front Quark Model
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作者 Shuai Xu Xiao-Nan Li Xing-Gang Wu 《Chinese Physics Letters》 2025年第8期31-37,共7页
In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius... In this paper,we study the ρ-meson electromagnetic form factors(EMFFs)within the framework of the light-front quark model.The physical form factors G_(C,M,Q)(Q^(2))of the ρ-meson,as well as the charged square radius<r^(2)>,the magnetic moment μ,and the quadrupole moment Q,are calculated,which describe the behaviors of EMFFs at zero momentum transfer.Using the type-Ⅱ replacement,we find that the zero-mode does contribute zero to the matrix element S_(00)^(+).It is found that the“M→M_(0)”replacement improves the angular condition remarkably,which permits different prescriptions of ρ-meson EMFFs to give the consistent results.The residual tiny violation of angular condition needs other explanations beyond the zero-mode contributions.Our results indicate that the relativistic effects or interaction internal structure are weaken in the zero-binding limit.This work is also applicable to other spin-1 particles. 展开更多
关键词 light front quark model zero mode contribution electromagnetic form factors emffs within relativistic effects rho meson magnetic moment electromagnetic form factors angular condition
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Light Use Efficiency Model Based on Chlorophyll Content Better Captures Seasonal Gross Primary Production Dynamics of Deciduous Broadleaf Forests
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作者 YANG Rongjuan LIU Ronggao +3 位作者 LIU Yang CHEN Jingming XU Mingzhu HE Jiaying 《Chinese Geographical Science》 2025年第1期55-72,共18页
Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes... Gross primary production(GPP)is a crucial indicator representing the absorption of atmospheric CO_(2) by vegetation.At present,the estimation of GPP by remote sensing is mainly based on leaf-related vegetation indexes and leaf-related biophysical para-meter leaf area index(LAI),which are not completely synchronized in seasonality with GPP.In this study,we proposed chlorophyll content-based light use efficiency model(CC-LUE)to improve GPP estimates,as chlorophyll is the direct site of photosynthesis,and only the light absorbed by chlorophyll is used in the photosynthetic process.The CC-LUE model is constructed by establishing a linear correlation between satellite-derived canopy chlorophyll content(Chlcanopy)and FPAR.This method was calibrated and validated utiliz-ing 7-d averaged in-situ GPP data from 14 eddy covariance flux towers covering deciduous broadleaf forest ecosystems across five dif-ferent climate zones.Results showed a relatively robust seasonal consistency between Chlcanopy with GPP in deciduous broadleaf forests under different climatic conditions.The CC-LUE model explained 88% of the in-situ GPP seasonality for all validation site-year and 56.0% of in-situ GPP variations through the growing season,outperforming the three widely used LUE models(MODIS-GPP algorithm,Vegetation Photosynthesis Model(VPM),and the eddy covariance-light use efficiency model(EC-LUE)).Additionally,the CC-LUE model(RMSE=0.50 g C/(m^(2)·d))significantly improved the underestimation of GPP during the growing season in semi-arid region,re-markably decreasing the root mean square error of averaged growing season GPP simulation and in-situ GPP by 75.4%,73.4%,and 37.5%,compared with MOD17(RMSE=2.03 g C/(m^(2)·d)),VPM(RMSE=1.88 g C/(m^(2)·d)),and EC-LUE(RMSE=0.80 g C/(m^(2)·d))model.The chlorophyll-based method proved superior in capturing the seasonal variations of GPP in forest ecosystems,thereby provid-ing the possibility of a more precise depiction of forest seasonal carbon uptake. 展开更多
关键词 canopy chlorophyll content(Chlcanopy) PHOTOSYNTHESIS gross primary production(GPP) light use efficiency(LUE)model seasonal dynamics deciduous broadleaf forest(DBF)
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LightDiffu-DCE:基于光照强度扩散的低光照图像增强
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作者 闫光辉 吴佰靖 马龙 《光学精密工程》 北大核心 2025年第7期1114-1129,共16页
针对低光照图像中不同光源的光照强度分布不均,在图像增强时造成轮廓特征丢失及效果不自然的问题,提出一种基于光照强度扩散的低光照图像增强方法(Light Diffusion based Zero-DCE Image Enhancement Algorithm,LightDiffu-DCE)。为增... 针对低光照图像中不同光源的光照强度分布不均,在图像增强时造成轮廓特征丢失及效果不自然的问题,提出一种基于光照强度扩散的低光照图像增强方法(Light Diffusion based Zero-DCE Image Enhancement Algorithm,LightDiffu-DCE)。为增强模型的泛化能力,提出了基于光源光照强度建模的扩散模型,以生成不同光照强度的训练数据集。设计了边缘特征融合的深度曲线估计网络,能够提取更丰富的低光照图像的多尺度轮廓和细节特征,提升对光照强度估计的准确性。为恢复出光照更加自然的图像,融合大气光估计来计算不同图像区域的光照强度,实现了对光增强曲线和光增强系数的动态微调。在无参考数据集ExDark和有参考数据集LOL上,使用6种评价指标进行实验分析。实验结果表明,相较于基准方法,LightDiffu-DCE在ExDark上的无参考评价指标NIQE,PIQE和RISQ上分别提升了约8.35%,6.20%和21.83%,在LOL数据集上的有参考评价指标PSNR,SSIM和RMSE提升了约12.12%,4.76%和49.89%。该方法可以有效增强低光照图像,且恢复出的低光照图像轮廓更加清晰,色彩鲜明且效果更自然。 展开更多
关键词 计算机视觉 扩散模型 低光照增强 边缘特征 深度曲线估计网络
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基于DDPM-LightGBM的电力CPS多标签不平衡虚假数据注入攻击的检测 被引量:1
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作者 李俊颉 高莲 +3 位作者 李鹏 张璇 杨家全 苏适 《昆明理工大学学报(自然科学版)》 北大核心 2025年第3期49-57,共9页
针对电力信息-物理系统(Cyber-Physical Systems,CPS)数据不平衡导致的多标签虚假数据注入攻击(False Data Injection Attack,FDIA)检测模型精度不高以及数据量大导致检测时间长的问题,提出了一种基于去噪扩散概率模型(Denoising Diffus... 针对电力信息-物理系统(Cyber-Physical Systems,CPS)数据不平衡导致的多标签虚假数据注入攻击(False Data Injection Attack,FDIA)检测模型精度不高以及数据量大导致检测时间长的问题,提出了一种基于去噪扩散概率模型(Denoising Diffusion Probabilistic Models,DDPM)和轻量梯度提升机(Light Gradient Boosting Machine,LightGBM)的FDIA检测模型.利用DDPM模型来生成数据集中不同标签的少数类攻击数据样本,解决数据集平衡问题,通过余弦相似性来对生成的数据的质量进行评价,从而判断数据生成的质量;采用LightGBM算法,通过直方图技术、梯度单边采样技术和互斥特征捆绑技术简化数据和模型复杂度,提升检测速度和精度.以密西西比州立大学和橡树岭国家实验室提供的电力CPS多标签数据集进行仿真实验,结果表明本模型能够生成高质量的攻击数据,解决数据不平衡问题,明显提升了对多标签FDIA的检测率. 展开更多
关键词 虚假数据注入攻击 去噪扩散概率模型 不平衡数据 轻量梯度提升机
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基于Light-GBM算法的地震动显著持时预测模型
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作者 崔铭钊 公茂盛 +3 位作者 左占宣 赵一男 贾佳 张孔 《振动与冲击》 北大核心 2025年第16期185-192,共8页
地震动持时对地震结构反应有显著影响,因此对考虑持时效应的工程结构抗震设计和区域地震危险性分析具有重要意义。该研究提出了一种基于轻量级梯度提升机(light gradient boosting machine,Light-GBM)算法的地震动显著持时预测模型,基于... 地震动持时对地震结构反应有显著影响,因此对考虑持时效应的工程结构抗震设计和区域地震危险性分析具有重要意义。该研究提出了一种基于轻量级梯度提升机(light gradient boosting machine,Light-GBM)算法的地震动显著持时预测模型,基于NGA-West2数据库,筛选了其中15541条地震动记录并计算其显著持时,随后通过特征重要性筛选输入参数并利用贝叶斯优化方法调整模型超参数,最终构建了地震动显著持时的预测模型,并与其他传统模型和深度学习模型对比,从而对模型的准确性和鲁棒性进行验证。结果表明,所建立的地震动显著持时预测模型具有良好预测性能、极高的计算效率和通用性,结果可供地震动持时预测及地震危险性分析等工作参考。 展开更多
关键词 地震动持时 预测模型 轻量级梯度提升机(light-GBM)算法 显著持时 机器学习
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LightGBM模型及模型可解释性方法在预测职业伤害严重程度中的探讨 被引量:1
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作者 莫有桦 张鹏 +2 位作者 谷一硕 朱晓俊 樊晶光 《环境与职业医学》 北大核心 2025年第2期157-164,共8页
[背景]轻量级梯度提升机算法(LightGBM)以其高效、快速等特点成为预测模型中的热门选择。然而,由于机器学习模型存在“黑盒”特性,导致模型可解释性较差。目前很少有研究从LightGBM模型及模型可解释性的角度评估职业伤害的严重程度。[目... [背景]轻量级梯度提升机算法(LightGBM)以其高效、快速等特点成为预测模型中的热门选择。然而,由于机器学习模型存在“黑盒”特性,导致模型可解释性较差。目前很少有研究从LightGBM模型及模型可解释性的角度评估职业伤害的严重程度。[目的]评估LightGBM模型及模型可解释性方法在职业伤害预测中的应用价值。[方法]应用美国矿山安全与健康管理局(MSHA)1983—2022年采矿业工人职业伤害数据集,以伤害程度(死亡/致命性职业伤害和永久/部分残疾)作为结局变量,以伤害发生的月份、年龄、性别、事故发生时间、轮班开始时间、事故发生时间与轮班开始时间间隔、总工龄、矿山总工龄、现矿山工龄、职业伤害致因、事故类型、伤害发生活动(即伤害发生时工人正在进行的活动)、伤害来源、受伤部位、作业环境类型、产品类别、伤害性质共17个指标作为预测变量。通过最小绝对收缩与选择算子算法(Lasso)回归方法筛选特征集。应用LightGBM构建职业伤害预测模型,以预测模型的曲线下面积(AUC)为主要评价指标,AUC越接近1,说明模型预测性能越好。应用Shapley加法解释(SHAP)法对模型可解释性进行评价。[结果]通过Lasso回归,识别出关键影响因素7个,分别为事故发生时间与轮班开始时间间隔、现矿山工龄、职业伤害致因、事故类型、受伤部位、伤害性质、作业环境类型。基于Lasso回归特征筛选构建的LightGBM模型预测性能良好,其AUC值、准确度、特异度、灵敏度分别为0.9941(95%CI:0.9917~0.9966)、0.9743、0.9781、0.9640,预测的致死性职业伤害概率与实际的致死性职业伤害概率一致性较高。在职业伤害预测模型中,通过SHAP值分析各指标的重要性,发现受伤部位和伤害性质是影响模型预测结果的两个主要特征,其他特征的影响较小。受伤部位的SHAP值分布广泛,尤其是头颈部和多部位的受伤,对预测致死性风险的模型有显著影响。伤害性质也对模型有不同方向的影响,窒息/溺水、挤压和多部位受伤对工人发生致死性职业伤害风险影响较大。[结论]LightGBM模型能够高效地处理大规模数据并提供高精度的预测结果。模型可解释性研究有助于更准确地探索、分析采矿业工人发生致死性职业伤害的各种风险关键因素,并进一步揭示这些因素间的复杂交互作用,从而为劳动工人提供更好的预防干预保护措施和最佳的资源配置。 展开更多
关键词 职业伤害 轻量级梯度提升机算法 预测模型 模型可解释性 Shapley加法解释
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Approach to Modeling and Virtual-reality-based Simulation for Plant Canopy Lighting
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作者 WANG Haopeng ZHAO Kai SONG Fengbin 《Chinese Geographical Science》 SCIE CSCD 2008年第4期374-381,共8页
Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ... Over the past 20 years, significant progress has been made in virtual plant modeling corresponding to the rapid advances in information technology. Virtual plant research has broad applications in agronomy, forestry, ecol- ogy and remote sensing. As many biological processes are driven by light, it is the key for virtual plant to estimate the light absorbed by each organ. This paper presents the radiance equation suitable for calculating sun and sky light intercepted by plant organs based on the principles of the interaction between light and plant canopy firstly; analyzes the process principles of plant canopy primary lighting based on ray casting and projection secondly; describes the multiple scattering of plant lighting based on Monte Carlo ray tracing method and on the radiosity method thirdly; and confirms the research with 3D visualization based on Virtual Reality Modeling Language (VRML) finally. The research is the primary work of digital agriculture, and important for monitoring and estimating corn growth in Northeast China. 展开更多
关键词 virtual plant canopy light modeling radiative modeling Virtual Reality modeling Language (VRML)
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基于TPE-LightGBM的平顶山煤田矿井水源判识模型研究
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作者 谢潇 鲁璐 《陕西煤炭》 2025年第6期13-20,共8页
快速识别突水水源类型是矿井水害防治的关键环节。为实现对平顶山煤田矿井水源的准确识别,分别提取地表水、第四系孔隙水、石炭系灰岩岩溶水、二叠系砂岩水和寒武系灰岩岩溶水的水样,并选择关键判别指标Na^(+)+K^(+)、Ca^(2+)、Mg^(2+)... 快速识别突水水源类型是矿井水害防治的关键环节。为实现对平顶山煤田矿井水源的准确识别,分别提取地表水、第四系孔隙水、石炭系灰岩岩溶水、二叠系砂岩水和寒武系灰岩岩溶水的水样,并选择关键判别指标Na^(+)+K^(+)、Ca^(2+)、Mg^(2+)、Cl^(-)、SO_(4)^(2-)、HCO_(3)^(-)进行分析。为避免模型因离群数据的干扰产生过拟合现象,利用箱型图准确地显示出数据的离散分布情况,并从数据中快速识别出20组异常值,对研究数据进行了清洗。将清洗后的数据以8∶2的比例划分为学习样本和测试样本,并将学习样本输入光梯度提升机(LightGBM)进行模型训练。利用树状结构帕森估计器(TPE)对LightGBM进行主要参数的优化,构建TPE-LightGBM模型。将LightGBM与TPE-LightGBM的结果对比可知,模型的精度提升了13.9%,表明TPE算法具有一定的有效性。为进一步验证模型的性能,将实验结果与随机搜索-多层感知机(RS-MLP)、遗传算法-极限梯度提升树(GA-XGBoost)模型进行比较。结果显示,TPE-LightGBM模型具有更高的精度和较低的泛化误差,这表明TPE-LightGBM在水源辨识中更具优势并且适用性较强。利用Gini系数对变量的贡献度进行量化,根据计算结果可知Ca^(2+)的贡献度最高,因此需要注意Ca^(2+)的浓度变化。综上所述,TPE-LightGBM具有较高的精确度和泛化能力,在水源识别问题上具有一定的指导意义。 展开更多
关键词 平顶山煤田 矿井水害 树状结构帕森估计器(TPE) 光梯度提升机(lightGBM) 智能化水源辨识模型
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Theoretical Models of Light Scattering Applied in Sizing Particles in Coal Water Slurry 被引量:1
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作者 王仁哲 张荣曾 徐志强 《Journal of China University of Mining and Technology》 2004年第1期64-66,81,共4页
Advantges and disadvantage of Mie scattering model and Fraunhofer diffraction model are discussed. The result shows that 1) the Fraunhofer diffraction model is simple in design and fast in operation, which is quite su... Advantges and disadvantage of Mie scattering model and Fraunhofer diffraction model are discussed. The result shows that 1) the Fraunhofer diffraction model is simple in design and fast in operation, which is quite suitable for on-line control and 2) the intensity and energy distribution of diffracted light of both the Mie scattering model and the Fraunhofer theoretical model are compared and researched. Feasibility of using the Fraunhofer diffraction model to replace the Mie scattering model in measuring particles in coal water slurry is demonstrated. 展开更多
关键词 coal water slurry light scattering model Mie scattering model DIFFRACTION
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Lighting Model of the Real World in Augmented Reality
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作者 周雅 闫达远 赵虎 《Journal of Beijing Institute of Technology》 EI CAS 2004年第2期165-168,共4页
Construction of a lighting model of the real world is one of the critical aims in an augmented reality (AR) system. The theory of lighting modeling used in computer graphics(CG) is applied in this study. The position... Construction of a lighting model of the real world is one of the critical aims in an augmented reality (AR) system. The theory of lighting modeling used in computer graphics(CG) is applied in this study. The position of the real light-source is first conjectured from light and shade of the registration image element by element using a ray tracking algorithm. Then the virtual light-source and virtual fiducial are constructed in the CG environment, in which, the Phong model is used to draw the light effect. By comparing the CG scene with the real image, one can modify the parameters of the lighting model over and over again, until the lighting effect of the CG scene is close enough to that of the real image. It is proved that this method works well in the indoor AR system. The method can be used feasibly in most applications with some improvements. 展开更多
关键词 augmented reality lighting model REGISTRATION
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Simulation of traffic flow with traffic light strategies via a modified cellular automaton model 被引量:1
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作者 何红弟 董力耘 戴世强 《Journal of Shanghai University(English Edition)》 CAS 2006年第3期189-191,共3页
Traffic flows controlled by traffic light strategies were investigated via a cellular automaton model with anticipation, which is suitable for describing urban traffic. Three kinds of strategies, i. e., synchronized, ... Traffic flows controlled by traffic light strategies were investigated via a cellular automaton model with anticipation, which is suitable for describing urban traffic. Three kinds of strategies, i. e., synchronized, green-wave and random switching lights, were designed, simulated and compared with each other. It is shown that the green-wave strategy is only valid at lower density and there is not an effective way with the three strategies to improve the efficiency of traffic flow at high density. 展开更多
关键词 traffic flow cellular automaton model trafflc light strategy.
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Electromagnetic Properties of S11 States in a Light Cone Quark Model
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作者 HE Jun DONG Yu-Bing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第2X期269-274,共6页
Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N(1535) and N(1650), and the helicity amplitudes A1... Using relativistic spin-flavor wave functions of a Lorentz-covariant light cone quark model, we calculate the electromagnetic form factors of two S11 resonances, N(1535) and N(1650), and the helicity amplitudes A1/2 and S1/2 for electroexcitation of the S11 resonances from the nucleon. The electromagnetic form factors of these S11 resonances are found to be similar to those of the nucleon in shape, while the charge form factor of neutral N(1650) is nearly zero. The relative peak height of the S11 charge form factors is controlled by the mixing angle common to both resonance wave functions. As in most quark models, there is a systematic overestimate of A1/2 in both N(1535) and N(1650) cases at the photon point. A sizeable S1/2 for all cases is produced as suggested by experiments. 展开更多
关键词 electromagntic properties S11 states light cone quark model
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Simplified prediction model for lighting energy consumption in office building scheme design
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作者 余琼 周潇儒 +1 位作者 林波荣 朱颖心 《Journal of Central South University》 SCIE EI CAS 2009年第S1期28-32,共5页
At the scheme design stage,the potential of daylighting is significant due to the saving for electric lighting use. There are few simple tools for architects to optimize the daylighting design. Therefore,it is useful ... At the scheme design stage,the potential of daylighting is significant due to the saving for electric lighting use. There are few simple tools for architects to optimize the daylighting design. Therefore,it is useful to develop a design guideline related to the evaluation of lighting energy saving potential and sunlight design strategies. This paper analyzes the impacts of different artificial lighting control methods and design parameters on daylighting. A direct correlation between lighting energy consumption and parameters such as orientations,window to wall ratio (WWR) and perimeter depth is established. A simplified prediction model is proposed to estimate lighting energy consumption with the given perimeter depth,WWR,and window transparency. Validation of the model is carried out compared with detailed lighting simulation software for an office building. After the variation analysis for these parameters,design advises for the daylighting design at scheme design phase are summarized. 展开更多
关键词 DAYlightING prediction model lightING ENERGY CONSUMPTION ENERGY-SAVING design GUIDELINE
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Light-absorbing Particles in Snow and Ice: Measurement and Modeling of Climatic and Hydrological impact 被引量:24
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作者 Yun QIAN Teppei J.YASUNARI +7 位作者 Sarah J.DOHERTY Mark G.FLANNER William K.M.LAU MING Jing Hailong WANG Mo WANG Stephen G.WARREN Rudong ZHANG 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2015年第1期64-91,共28页
Light absorbing particles(LAP, e.g., black carbon, brown carbon, and dust) influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated with atmospheric... Light absorbing particles(LAP, e.g., black carbon, brown carbon, and dust) influence water and energy budgets of the atmosphere and snowpack in multiple ways. In addition to their effects associated with atmospheric heating by absorption of solar radiation and interactions with clouds, LAP in snow on land and ice can reduce the surface reflectance(a.k.a., surface darkening), which is likely to accelerate the snow aging process and further reduces snow albedo and increases the speed of snowpack melt. LAP in snow and ice(LAPSI) has been identified as one of major forcings affecting climate change, e.g.in the fourth and fifth assessment reports of IPCC. However, the uncertainty level in quantifying this effect remains very high. In this review paper, we document various technical methods of measuring LAPSI and review the progress made in measuring the LAPSI in Arctic, Tibetan Plateau and other mid-latitude regions. We also report the progress in modeling the mass concentrations, albedo reduction, radiative forcing, and climatic and hydrological impact of LAPSI at global and regional scales. Finally we identify some research needs for reducing the uncertainties in the impact of LAPSI on global and regional climate and the hydrological cycle. 展开更多
关键词 light-absorbing aerosol SNOW ice ALBEDO MEASUREMENT climate modeling hydrological cycle
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Stochastic Modelling of Relative Light Sensitivity of Hair Follicles
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作者 Ilja L. Kruglikov 《Open Journal of Biophysics》 2013年第3期201-205,共5页
Relative light sensitivity (RLS) of HFs was mathematically described as the ratio of two stochastic variables presenting the durations of light sensitive and light insensitive sub-phases of the cycle according to a ne... Relative light sensitivity (RLS) of HFs was mathematically described as the ratio of two stochastic variables presenting the durations of light sensitive and light insensitive sub-phases of the cycle according to a new theory of HF light sensitivity formulated in our previous article (Kruglikov, Am J Cosm Surg, 2012, 29:266 - 272). RLS gives possibility to rank the HFs from different body regions according to their light sensitivities. Application of proposed method for estimation of the light sensitivity of scalp hairs predicts remarkable difference in light sensitivities of HFs in alopecic and non-alopecic patients. 展开更多
关键词 light Sensitivity HAIR Follicle MATHEMATICAL model
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Evaluating the Conservation Efforts of Multi-Projects Using Remote Sensing and Light Use Efficiency Model: A Case of Nyungwe Forest National Park, Rwanda
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作者 Evariste Rutebuka Lixiao Zhang +2 位作者 Ernest Frimpong Asamoah Emmanuel Rukundo Apollinaire William 《Open Journal of Forestry》 2018年第1期68-86,共19页
This paper investigates the effectiveness of conservation efforts in the Nyungwe Forest National Park (Nyungwe). The forest is one of the six key landscapes identified for conservation in the Albertine Rift because it... This paper investigates the effectiveness of conservation efforts in the Nyungwe Forest National Park (Nyungwe). The forest is one of the six key landscapes identified for conservation in the Albertine Rift because it hosts many threatened species. As such, a number of different stakeholders have been involved in its conservation since 1987;yet, studies that emphasize and evaluate the success of these conservation efforts are limited. We combined a rapid and relatively low cost remotely-sensed data and the Light Use Efficiency model to generate forest conservation indicators such as NDVI, forest canopy Net Primary Productivity and carbon sequestered from 1986 to 2010. The influence of topographic and climatic factors on these indicators was examined. The supervised classifier was used to catalogue the area into Forest, Wetland, and Bareland. The forest was the major category (above 90%) of Nyungwe relative to wetland and bareland. Based on degradation intensity, two distinctive periods were realised;the first period spans 8 years (1986-1994) whereas the second spans 16 years (1994-2010). The former degradation intensity period is 10 times higher than the latter period. Although the size of forest recovered up to 90%, the daily NPP and carbon sequestration capacity decreased by 37.1% (i.e. NPP 6.5 Mg tons in 1986 to 4.1 Mg tons in 2010). Areas of the forest that are physically constrained (high altitude) had a higher degradation. Guided by our indicators, there is an overall success in conservation efforts, but efforts were mostly concentrated in accessible areas. Therefore, conservation efforts that aim to respond to degradation of the inaccessible areas of the forest should be stressed in the management plan of the park. 展开更多
关键词 CONSERVATION EFFORTS FOREST CANOPY COVER light Use Efficiency model Remote Sensing Nyungwe Rwanda
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Research and Application of Caideng Model Rendering Technology for Virtual Reality
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作者 Xuefeng Wang Yadong Wu +1 位作者 Yan Luo Dan Luo 《Journal of Computer and Communications》 2024年第4期95-110,共16页
With the development of virtual reality (VR) technology, more and more industries are beginning to integrate with VR technology. In response to the problem of not being able to directly render the lighting effect of C... With the development of virtual reality (VR) technology, more and more industries are beginning to integrate with VR technology. In response to the problem of not being able to directly render the lighting effect of Caideng in digital Caideng scenes, this article analyzes the lighting model. It combines it with the lighting effect of Caideng scenes to design an optimized lighting model algorithm that fuses the bidirectional transmission distribution function (BTDF) model. This algorithm can efficiently render the lighting effect of Caideng models in a virtual environment. And using image optimization processing methods, the immersive experience effect on the VR is enhanced. Finally, a Caideng roaming interactive system was designed based on this method. The results show that the frame rate of the system is stable during operation, maintained above 60 fps, and has a good immersive experience. 展开更多
关键词 Virtual Reality Caideng model lighting model Point light Rendering
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通信延迟对车联网交通流演化的影响
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作者 陈宇峰 游康祥 +2 位作者 王琰 向郑涛 周旭 《公路交通科技》 北大核心 2025年第4期17-23,共7页
【目标】车联网是未来智能交通系统的核心组成部分,研究车联网环境下联网车辆渗透率和通信延迟对交通流稳定性及演化复杂性的影响具有重要意义。【方法】基于联网车辆和普通车辆对交通信息获取的差异性,区分联网车辆与普通车辆的期望间... 【目标】车联网是未来智能交通系统的核心组成部分,研究车联网环境下联网车辆渗透率和通信延迟对交通流稳定性及演化复杂性的影响具有重要意义。【方法】基于联网车辆和普通车辆对交通信息获取的差异性,区分联网车辆与普通车辆的期望间距规则和随机慢化规则,提出了考虑通信延迟影响的改进刹车灯元胞自动机模型,并通过数值模拟分析不同联网车辆渗透率和通信延迟下的交通流演化特性。【结果】数值模拟表明:(1)联网车辆渗透率的提高显著提升了道路通行能力,渗透率分别为0,0.5和1时,交通流量最大值可分别达到2.5,3.16和4.58;(2)通信延迟的增加导致道路最大交通流量下降,延迟为0.8 s时比0.1,0.3 s和0.5 s分别下降18.18%,13.76%和8.31%;(3)车联网通信延迟越大,交通流越不稳定,通信延迟分别为0.3,0.5 s和0.8 s时,流量样本开始出现波动的车流密度分别为0.22,0.21和0.19,说明随着通信延迟的增大,交通流将更早进入宽运动堵塞状态。【结论】联网车辆的普及有助于缓解交通拥堵,但通信延迟对交通流稳定性和演化复杂性有显著的负面影响,降低通信延迟是提升车联网交通流效率的关键。 展开更多
关键词 智能交通 改进刹车灯模型 元胞自动机 车联网 通信延迟
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基于LightGBM和可解释代理模型的风电场并网振荡稳定分析与控制
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作者 黄佳健 王宝华 韩杰 《武汉大学学报(工学版)》 CAS CSCD 北大核心 2024年第10期1424-1433,共10页
针对目前风电场并网振荡稳定评估的研究未考虑串补和黑箱模型无法充分被信任的问题,提出一种考虑串补特征的基于轻量级梯度提升机(light gradient boosting machine,Light GBM)和可解释代理模型的风电场并网振荡稳定在线评估和控制方法... 针对目前风电场并网振荡稳定评估的研究未考虑串补和黑箱模型无法充分被信任的问题,提出一种考虑串补特征的基于轻量级梯度提升机(light gradient boosting machine,Light GBM)和可解释代理模型的风电场并网振荡稳定在线评估和控制方法。利用模式分析法构造训练数据集,建立基于LightGBM的振荡稳定评估模型;提出基于广义加性模型的局部可解释模型的控制方法。在Simulink中搭建多风电场并网系统的仿真模型,验证了所提方法能有效地进行振荡稳定评估和抑制振荡。相比传统线性回归作为可解释代理模型,该方法能够充分拟合复杂模型,并对系统进行有效的针对性控制。 展开更多
关键词 振荡 稳定评估 轻量级梯度提升机 优化控制 代理模型
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