Traditional feature-based turbine blade models can match the needs of geometric modeling but could hardly meet the requirement of data extraction in 1-D heat transfer analysis. In this paper, the requirements of data ...Traditional feature-based turbine blade models can match the needs of geometric modeling but could hardly meet the requirement of data extraction in 1-D heat transfer analysis. In this paper, the requirements of data extraction in 1-D heat transfer analysis are taken into consideration as well as geometric representation in parametric design process. An improved turbine blade parametric modeling method is proposed. Based on the modeling method proposed, a system structure of blade modeling process considering 1-D heat transfer analysis is devised. Eventually, a turbine blade parametric modeling system is constructed to test and verify the feasibility of the proposed modeling method and system structure. Experiments show that the blade parametric modeling method proposed can make geometric models better adapt to the specific requirements of 1-D heat transfer analysis and has certain reference value to the creation of high quality digital models.展开更多
In this paper,the latest progress,major achievements and future plans of Chinese meteorological satellites and the core data processing techniques are discussed.First,the latest three FengYun(FY)meteorological satelli...In this paper,the latest progress,major achievements and future plans of Chinese meteorological satellites and the core data processing techniques are discussed.First,the latest three FengYun(FY)meteorological satellites(FY-2H,FY-3D,and FY-4A)and their primary objectives are introduced Second,the core image navigation techniques and accuracies of the FY meteorological satellites are elaborated,including the latest geostationary(FY-2/4)and polar-orbit(FY-3)satellites.Third,the radiometric calibration techniques and accuracies of reflective solar bands,thermal infrared bands,and passive microwave bands for FY meteorological satellites are discussed.It also illustrates the latest progress of real-time calibration with the onboard calibration system and validation with different methods,including the vicarious China radiance calibration site calibration,pseudo invariant calibration site calibration,deep convective clouds calibration,and lunar calibration.Fourth,recent progress of meteorological satellite data assimilation applications and quantitative science produce are summarized at length.The main progress is in meteorological satellite data assimilation by using microwave and hyper-spectral infrared sensors in global and regional numerical weather prediction models.Lastly,the latest progress in radiative transfer,absorption and scattering calculations for satellite remote sensing is summarized,and some important research using a new radiative transfer model are illustrated.展开更多
传统移相控制下,无线电能传输(Wireles power transfer,WPT)系统输出功率宽范围调节时逆变器开关管易丢失零电压开关(Zero voltage switching,ZVS)状态,导致逆变器切换损耗增大甚至损坏。阶跃脉冲调制(Stepped Pulse Modulation)是一种...传统移相控制下,无线电能传输(Wireles power transfer,WPT)系统输出功率宽范围调节时逆变器开关管易丢失零电压开关(Zero voltage switching,ZVS)状态,导致逆变器切换损耗增大甚至损坏。阶跃脉冲调制(Stepped Pulse Modulation)是一种低输出纹波调制方法,可实现宽负载范围内的ZVS运行。但是,该调制方法包含有限状态机等环节,不易采用传统的机理建模访求进行建模,给控制器设计带来困难。在Simulink电路的基础上,基于数据驱动方法辨识了无线电能传输在阶跃脉冲调制下传递函数模型,并基于该模型设计内模控制器。实验表明,基于Simulink电路仿真方法获取采样数据,能够有效解决实物实验在某些场景下难以获取实验数据的难题,获得满意的辨识模型。同时,基于辨识模型设计的内模控制器,能够精确估计不同控制参数下的系统控制性能,满足了阶跃脉冲调制无线电能传输输出电压闭环控制的性能需求。展开更多
Geo-Spatial Data Transfer Standard is an important part of 'National Spatial Data Infrastructure(NSDI)' ,as well as a necessary means for data sharing. 'Chinese National Geo-Spatial Data Transfer Format (C...Geo-Spatial Data Transfer Standard is an important part of 'National Spatial Data Infrastructure(NSDI)' ,as well as a necessary means for data sharing. 'Chinese National Geo-Spatial Data Transfer Format (CNSDTF)' was approved by National Quality Technology Supervise Bureau in 1999 with the standard serial number of 17798-1999. It is designed to support vector and raster spatial data. This paper describes the vector part of CNSDTF, including design ideas, main characters, conceptual model, definition of spatial object, and file structure.展开更多
属性级情感分析作为一种细粒度情感分析方法,目前在许多应用场景中都具有重要作用.然而,随着社交媒体和在线评论的日益广泛以及各类新兴领域的出现,使得跨领域属性级情感分析面临着标签数据不足以及源领域与目标领域文本分布差异等挑战...属性级情感分析作为一种细粒度情感分析方法,目前在许多应用场景中都具有重要作用.然而,随着社交媒体和在线评论的日益广泛以及各类新兴领域的出现,使得跨领域属性级情感分析面临着标签数据不足以及源领域与目标领域文本分布差异等挑战.目前已有许多数据增强方法试图解决这些问题,但现有方法生成的文本仍存在语义不连贯、结构单一以及特征与源领域过于趋同等问题.为了克服这些问题,提出一种基于大语言模型(large language model,LLM)数据增强的跨领域属性级情感分析方法.所提方法利用大模型丰富的语言知识,合理构建针对跨领域属性级别情感分析任务的引导语句,挖掘目标领域与源领域相似文本,通过上下文学习的方式,使用领域关联关键词引导LLM生成目标领域有标签文本数据,用以解决目标领域数据缺乏以及领域特异性问题,从而有效提高跨领域属性级情感分析的准确性和鲁棒性.所提方法在多个真实数据集中进行实验,实验结果表明,该方法可以有效提升基线模型在跨领域属性级情感分析中的表现.展开更多
Generally, predicting whether an item will be liked or disliked by active users, and how much an item will be liked, is a main task of collaborative filtering systems or recommender systems. Recently, predicting most ...Generally, predicting whether an item will be liked or disliked by active users, and how much an item will be liked, is a main task of collaborative filtering systems or recommender systems. Recently, predicting most likely bought items for a target user, which is a subproblem of the rank problem of collaborative filtering, became an important task in collaborative filtering. Traditionally, the prediction uses the user item co-occurrence data based on users' buying behaviors. However, it is challenging to achieve good prediction performance using traditional methods based on single domain information due to the extreme sparsity of the buying matrix. In this paper, we propose a novel method called the preference transfer model for effective cross-domain collaborative filtering. Based on the preference transfer model, a common basis item-factor matrix and different user-factor matrices are factorized.Each user-factor matrix can be viewed as user preference in terms of browsing behavior or buying behavior. Then,two factor-user matrices can be used to construct a so-called ‘preference dictionary' that can discover in advance the consistent preference of users, from their browsing behaviors to their buying behaviors. Experimental results demonstrate that the proposed preference transfer model outperforms the other methods on the Alibaba Tmall data set provided by the Alibaba Group.展开更多
文摘Traditional feature-based turbine blade models can match the needs of geometric modeling but could hardly meet the requirement of data extraction in 1-D heat transfer analysis. In this paper, the requirements of data extraction in 1-D heat transfer analysis are taken into consideration as well as geometric representation in parametric design process. An improved turbine blade parametric modeling method is proposed. Based on the modeling method proposed, a system structure of blade modeling process considering 1-D heat transfer analysis is devised. Eventually, a turbine blade parametric modeling system is constructed to test and verify the feasibility of the proposed modeling method and system structure. Experiments show that the blade parametric modeling method proposed can make geometric models better adapt to the specific requirements of 1-D heat transfer analysis and has certain reference value to the creation of high quality digital models.
基金funded by the National Key R&D Program of China(Grant Nos.2018YFB0504900 and 2015AA123700)
文摘In this paper,the latest progress,major achievements and future plans of Chinese meteorological satellites and the core data processing techniques are discussed.First,the latest three FengYun(FY)meteorological satellites(FY-2H,FY-3D,and FY-4A)and their primary objectives are introduced Second,the core image navigation techniques and accuracies of the FY meteorological satellites are elaborated,including the latest geostationary(FY-2/4)and polar-orbit(FY-3)satellites.Third,the radiometric calibration techniques and accuracies of reflective solar bands,thermal infrared bands,and passive microwave bands for FY meteorological satellites are discussed.It also illustrates the latest progress of real-time calibration with the onboard calibration system and validation with different methods,including the vicarious China radiance calibration site calibration,pseudo invariant calibration site calibration,deep convective clouds calibration,and lunar calibration.Fourth,recent progress of meteorological satellite data assimilation applications and quantitative science produce are summarized at length.The main progress is in meteorological satellite data assimilation by using microwave and hyper-spectral infrared sensors in global and regional numerical weather prediction models.Lastly,the latest progress in radiative transfer,absorption and scattering calculations for satellite remote sensing is summarized,and some important research using a new radiative transfer model are illustrated.
文摘传统移相控制下,无线电能传输(Wireles power transfer,WPT)系统输出功率宽范围调节时逆变器开关管易丢失零电压开关(Zero voltage switching,ZVS)状态,导致逆变器切换损耗增大甚至损坏。阶跃脉冲调制(Stepped Pulse Modulation)是一种低输出纹波调制方法,可实现宽负载范围内的ZVS运行。但是,该调制方法包含有限状态机等环节,不易采用传统的机理建模访求进行建模,给控制器设计带来困难。在Simulink电路的基础上,基于数据驱动方法辨识了无线电能传输在阶跃脉冲调制下传递函数模型,并基于该模型设计内模控制器。实验表明,基于Simulink电路仿真方法获取采样数据,能够有效解决实物实验在某些场景下难以获取实验数据的难题,获得满意的辨识模型。同时,基于辨识模型设计的内模控制器,能够精确估计不同控制参数下的系统控制性能,满足了阶跃脉冲调制无线电能传输输出电压闭环控制的性能需求。
基金Project supported by the National Outstanding Youth Researchers Foundation(No.49525101)
文摘Geo-Spatial Data Transfer Standard is an important part of 'National Spatial Data Infrastructure(NSDI)' ,as well as a necessary means for data sharing. 'Chinese National Geo-Spatial Data Transfer Format (CNSDTF)' was approved by National Quality Technology Supervise Bureau in 1999 with the standard serial number of 17798-1999. It is designed to support vector and raster spatial data. This paper describes the vector part of CNSDTF, including design ideas, main characters, conceptual model, definition of spatial object, and file structure.
文摘属性级情感分析作为一种细粒度情感分析方法,目前在许多应用场景中都具有重要作用.然而,随着社交媒体和在线评论的日益广泛以及各类新兴领域的出现,使得跨领域属性级情感分析面临着标签数据不足以及源领域与目标领域文本分布差异等挑战.目前已有许多数据增强方法试图解决这些问题,但现有方法生成的文本仍存在语义不连贯、结构单一以及特征与源领域过于趋同等问题.为了克服这些问题,提出一种基于大语言模型(large language model,LLM)数据增强的跨领域属性级情感分析方法.所提方法利用大模型丰富的语言知识,合理构建针对跨领域属性级别情感分析任务的引导语句,挖掘目标领域与源领域相似文本,通过上下文学习的方式,使用领域关联关键词引导LLM生成目标领域有标签文本数据,用以解决目标领域数据缺乏以及领域特异性问题,从而有效提高跨领域属性级情感分析的准确性和鲁棒性.所提方法在多个真实数据集中进行实验,实验结果表明,该方法可以有效提升基线模型在跨领域属性级情感分析中的表现.
基金supported by the National Basic Research Program(973)of China(No.2012CB316400)the National Natural Science Foundation of China(No.61571393)
文摘Generally, predicting whether an item will be liked or disliked by active users, and how much an item will be liked, is a main task of collaborative filtering systems or recommender systems. Recently, predicting most likely bought items for a target user, which is a subproblem of the rank problem of collaborative filtering, became an important task in collaborative filtering. Traditionally, the prediction uses the user item co-occurrence data based on users' buying behaviors. However, it is challenging to achieve good prediction performance using traditional methods based on single domain information due to the extreme sparsity of the buying matrix. In this paper, we propose a novel method called the preference transfer model for effective cross-domain collaborative filtering. Based on the preference transfer model, a common basis item-factor matrix and different user-factor matrices are factorized.Each user-factor matrix can be viewed as user preference in terms of browsing behavior or buying behavior. Then,two factor-user matrices can be used to construct a so-called ‘preference dictionary' that can discover in advance the consistent preference of users, from their browsing behaviors to their buying behaviors. Experimental results demonstrate that the proposed preference transfer model outperforms the other methods on the Alibaba Tmall data set provided by the Alibaba Group.
