Consider an initial-boundary problem vt - ux=0,u, + （）x + f（u） = （）x,θt+ux=（）ux=（）x+ （E） v（x,0） = v0（x）,u（x,0） = u0（x）,θ（0,x） = θ0（x）, （I） u（t,0） = u（t,1） = θx（t,0） = θx（t,1） （J...Consider an initial-boundary problem vt - ux=0,u, + （）x + f（u） = （）x,θt+ux=（）ux=（）x+ （E） v（x,0） = v0（x）,u（x,0） = u0（x）,θ（0,x） = θ0（x）, （I） u（t,0） = u（t,1） = θx（t,0） = θx（t,1） （J） Sufficient and necessary conditions for （E）, （I） and （J） to have asymptotic stability of the gobal smooth solution are given by means of the elemental L2 energy method.展开更多
由于现有的多数概念演化检测方法本质上是基于监督学习,且通常用于解决一个时间段内仅出现一个新类,不能处理数据流中的类消失和类循环任务。为此,提出一种基于弱监督集成的概念演化自适应检测方法(AD_WE:Adaptive Detection Method for...由于现有的多数概念演化检测方法本质上是基于监督学习,且通常用于解决一个时间段内仅出现一个新类,不能处理数据流中的类消失和类循环任务。为此,提出一种基于弱监督集成的概念演化自适应检测方法(AD_WE:Adaptive Detection Method for Concept Evolution Based on Weakly Supervised Ensemble)。该方法利用弱监督集成策略构建集成学习器,对数据块中的训练样本进行局部预测,在此基础上,基于局部密度和相对距离识别特征空间中具有较强内聚性的相似数据并对其聚类,对聚类结果进行相似度比较,实现新类实例的检测及不同新类的区分;同时根据数据随时间变化特征建立动态衰减模型,及时消除消失类,并通过相似度比较检测循环类。实验表明,所提方法能对概念演化做出及时响应,可有效识别消失类和循环类,提高学习器的泛化性能。展开更多
Industry foundation classes(IFC)is an open and neutral data format specification for building information modeling(BIM)that plays a crucial role in facilitating interoperability.With increases in web-based BIM applica...Industry foundation classes(IFC)is an open and neutral data format specification for building information modeling(BIM)that plays a crucial role in facilitating interoperability.With increases in web-based BIM applications,there is an urgent need for fast loading large IFC models on a web browser.However,the task of fully loading large IFC models typically consumes a large amount of memory of a web browser or even crashes the browser,and this significantly limits further BIM applications.In order to address the issue,a method is proposed for dynamically loading IFC models based on spatial semantic partitioning(SSP).First,the spatial semantic structure of an input IFC model is partitioned via the extraction of story information and establishing a component space index table on the server.Subsequently,based on user interaction,only the model data that a user is interested in is transmitted,loaded,and displayed on the client.The presented method is implemented via Web Graphics Library,and this enables large IFC models to be fast loaded on the web browser without requiring any plug-ins.When compared with conventional methods that load all IFC model data for display purposes,the proposed method significantly reduces memory consumption in a web browser,thereby allowing the loading of large IFC models.When compared with the existing method of spatial partitioning for 3D data,the proposed SSP entirely uses semantic information in the IFC file itself,and thereby provides a better interactive experience for users.展开更多
This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a h...This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a high 37 dB output power dynamic range with good average power adding efficiency. The measurement results show that the PA achieves a high power gain of 23 dBm and power added efficiency (PAE) by 38%. The circuit was post layout simulated in a standard 0.18 μm CMOS technology.展开更多
以某型无人直升机为仿真对象设计了一款飞行模拟系统,该系统由飞行仿真模块、座舱仿真模块、视景仿真模块和控制台模块4部分组成。飞行仿真模块对旋翼、尾桨、机身、平尾、垂尾等各部件进行动力学建模,并使用S函数编写了Simulink模块;...以某型无人直升机为仿真对象设计了一款飞行模拟系统,该系统由飞行仿真模块、座舱仿真模块、视景仿真模块和控制台模块4部分组成。飞行仿真模块对旋翼、尾桨、机身、平尾、垂尾等各部件进行动力学建模,并使用S函数编写了Simulink模块;座舱仿真模块使用GL Studio软件设计了照片级的飞行仪表用于实时显示飞行数据;视景仿真模块是基于Vega Prime仿真平台二次开发的;采用基于MFC(microsoft foundation classes)的多线程方法搭建了基本的仿真框架并设计了控制台模块界面,可以用于和用户的实时交互。最后仿真验证了系统的可行性。展开更多
文摘Consider an initial-boundary problem vt - ux=0,u, + （）x + f（u） = （）x,θt+ux=（）ux=（）x+ （E） v（x,0） = v0（x）,u（x,0） = u0（x）,θ（0,x） = θ0（x）, （I） u（t,0） = u（t,1） = θx（t,0） = θx（t,1） （J） Sufficient and necessary conditions for （E）, （I） and （J） to have asymptotic stability of the gobal smooth solution are given by means of the elemental L2 energy method.
文摘由于现有的多数概念演化检测方法本质上是基于监督学习,且通常用于解决一个时间段内仅出现一个新类,不能处理数据流中的类消失和类循环任务。为此,提出一种基于弱监督集成的概念演化自适应检测方法(AD_WE:Adaptive Detection Method for Concept Evolution Based on Weakly Supervised Ensemble)。该方法利用弱监督集成策略构建集成学习器,对数据块中的训练样本进行局部预测,在此基础上,基于局部密度和相对距离识别特征空间中具有较强内聚性的相似数据并对其聚类,对聚类结果进行相似度比较,实现新类实例的检测及不同新类的区分;同时根据数据随时间变化特征建立动态衰减模型,及时消除消失类,并通过相似度比较检测循环类。实验表明,所提方法能对概念演化做出及时响应,可有效识别消失类和循环类,提高学习器的泛化性能。
基金The study was supported by the National Key R&D Program of China(No.2018YFB0505400)the National Natural Science Foundation of China(No.61472202)+1 种基金the Special Scientific Research Fund of China Railway Corporation(No.J2017X010)the Research on Key Technologies of Virtual Engineering of Railway Engineering Unit Based on BIM Technology(No.K2018G055).
文摘Industry foundation classes(IFC)is an open and neutral data format specification for building information modeling(BIM)that plays a crucial role in facilitating interoperability.With increases in web-based BIM applications,there is an urgent need for fast loading large IFC models on a web browser.However,the task of fully loading large IFC models typically consumes a large amount of memory of a web browser or even crashes the browser,and this significantly limits further BIM applications.In order to address the issue,a method is proposed for dynamically loading IFC models based on spatial semantic partitioning(SSP).First,the spatial semantic structure of an input IFC model is partitioned via the extraction of story information and establishing a component space index table on the server.Subsequently,based on user interaction,only the model data that a user is interested in is transmitted,loaded,and displayed on the client.The presented method is implemented via Web Graphics Library,and this enables large IFC models to be fast loaded on the web browser without requiring any plug-ins.When compared with conventional methods that load all IFC model data for display purposes,the proposed method significantly reduces memory consumption in a web browser,thereby allowing the loading of large IFC models.When compared with the existing method of spatial partitioning for 3D data,the proposed SSP entirely uses semantic information in the IFC file itself,and thereby provides a better interactive experience for users.
文摘This paper presents a 1.8 GHz class-E controlled power amplifier (PA). The proposed power amplifier is designed with two-stage architecture. The main advantage of the proposed technique for output control power is a high 37 dB output power dynamic range with good average power adding efficiency. The measurement results show that the PA achieves a high power gain of 23 dBm and power added efficiency (PAE) by 38%. The circuit was post layout simulated in a standard 0.18 μm CMOS technology.
文摘以某型无人直升机为仿真对象设计了一款飞行模拟系统,该系统由飞行仿真模块、座舱仿真模块、视景仿真模块和控制台模块4部分组成。飞行仿真模块对旋翼、尾桨、机身、平尾、垂尾等各部件进行动力学建模,并使用S函数编写了Simulink模块;座舱仿真模块使用GL Studio软件设计了照片级的飞行仪表用于实时显示飞行数据;视景仿真模块是基于Vega Prime仿真平台二次开发的;采用基于MFC(microsoft foundation classes)的多线程方法搭建了基本的仿真框架并设计了控制台模块界面,可以用于和用户的实时交互。最后仿真验证了系统的可行性。
