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Structural properties and generative model of non-giant connected components in social networks

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Science China Earth Sciences 2016年第12期59卷 229-234页

作者： jianwei niu Lei WANG State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and EngineeringBeihang University

Most previous studies have mainly focused on the analyses of one entire network(graph) or the giant connected components of networks. In this paper, we investigate the disconnected components(non-giant connected component) of some real social networks, and report some interesting discoveries about structural properties of disconnected components. We study three diverse, real networks and compute the significance profile of each component. We discover some similarities in the local structure between the giant connected component and disconnected components in diverse social networks. Then we discuss how to detect network attacks based on the local structure properties of networks. Furthermore, we propose an empirical generative model called i Friends to generate networks that follow our observed patterns.

关键词： disconnected components giant connected component structural properties significance profile generative model

An Energy-Efficient Data Collection Scheme Using Denoising Autoencoder in Wireless Sensor Networks

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Tsinghua Science and Technology 2019年第1期24卷 86-96页

作者： Guorui Li Sancheng Peng Cong Wang jianwei niu Ying Yuan School of Computer Science and Engineering Northeastern University School of Information Science and Technology Guangdong University of Foreign Studies State Key Laboratory of Virtual Reality Technology and Systems Beihang University

As one of the key operations in Wireless Sensor Networks(WSNs), the energy-efficient data collection schemes have been actively explored in the literature. However, the transform basis for sparsifing the sensed data is usually chosen empirically, and the transformed results are not always the sparsest. In this paper, we propose a Data Collection scheme based on Denoising Autoencoder(DCDA) to solve the above problem. In the data training phase, a Denoising AutoEncoder(DAE) is trained to compute the data measurement matrix and the data reconstruction matrix using the historical sensed data. Then, in the data collection phase, the sensed data of whole network are collected along a data collection tree. The data measurement matrix is utilized to compress the sensed data in each sensor node, and the data reconstruction matrix is utilized to reconstruct the original data in the ***, the data communication performance and data reconstruction performance of the proposed scheme are evaluated and compared with those of existing schemes using real-world sensed data. The experimental results show that compared to its counterparts, the proposed scheme results in a higher data compression rate, lower energy consumption, more accurate data reconstruction, and faster data reconstruction speed.

关键词： wireless sensor networks data collection neural networks autoencoder data reconstruction

万宁日月湾近岸海域悬浮泥沙输运特征及沉积动力环境分析

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海洋湖沼通报（中英文） 2024年第3期46卷 73-81页

作者：林纪江王平张卓唐灵王蕾游大伟聂宇华牛建伟国家海洋局南海信息中心广东广州510310 南方海洋科学与工程广东省实验室(珠海) 广东珠海519000 自然资源部海洋环境探测技术与应用重点实验室广东广州510310 福建省港航管理局勘测中心福建福州350009 中国科学院南海海洋研究所广东广州510301

依据实测悬浮泥沙和同步观测的海流数据,利用悬沙通量机制分解法计算各站潮平均单宽输沙量,分析研究区海域的悬沙输运机制及主要的力学控制因素。依据表层沉积物的粒度数据,分析了研究区表层沉积物的分布特征,并利用Flemming三角图示法... 详细信息

依据实测悬浮泥沙和同步观测的海流数据,利用悬沙通量机制分解法计算各站潮平均单宽输沙量,分析研究区海域的悬沙输运机制及主要的力学控制因素。依据表层沉积物的粒度数据,分析了研究区表层沉积物的分布特征,并利用Flemming三角图示法对研究区进行沉积动力环境分区。结果表明,研究区悬浮泥沙输移主要受拉格朗日平流输运控制,垂向净环流影响次之;潮平均单宽净输沙量输运方向为SW向,与研究区余流方向基本一致;外侧站位潮平均单宽输沙量呈现自东北向西南方向递减趋势,而内侧站位却相反,潮平均单宽输沙量呈现自东北向西南方向递增趋势,表明近岸有沙源供给,近岸侵蚀或河流输沙;研究区整体被砂覆盖,局部区域为粉砂质砂、砾质砂、砂质砾,存在少量贝壳或珊瑚礁;水动力环境可划分为S区、A区和B区,表层沉积物由推移、跃移、悬移三类运动方式的物质组成,其中以跃移物质为主,随着水动力环境变弱,表层沉积物的跃移组分含量降低,悬移组分含量升高。

关键词：悬浮泥沙沉积动力环境输运机制余流

Variations of suspended sediment transport caused by changes in shoreline and bathymetry in the Zhujiang(Pearl)River Estuary in the wet season

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Acta Oceanologica Sinica 2022年第10期41卷 54-73页

作者： Shicheng Lin jianwei niu Guangping Liu Xing Wei Shuqun Cai State Key Laboratory of Tropical Oceanography South China Sea Institute of OceanologyChinese Academy of SciencesGuangzhou510301China Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou) Guangzhou511458China University of Chinese Academy of Sciences Beijing100049China Institution of South China Sea Ecology and Environmental Engineering Chinese Academy of SciencesGuangzhou510301China

A wave-current-sediment coupled numerical model is employed to study the responses of suspended sediment transport in the wet season to changes in shoreline and bathymetry in the Zhujiang(Pearl)River Estuary(ZRE)from 1971 to *** is shown that,during the wavy period,the large wave-induced bottom stress enhances sediment resuspension,resulting in an increase in the area of suspended sediment concentration(SSC)greater than 100 mg/L by 183.4%.On one hand,in spring tide,the change in shoreline reduces the area of SSC greater than 100 mg/L by 17.8%in the west shoal(WS)but increases the SSC,owing to the closer sediment source to the offshore and the stronger residual current at the Hengmeng(HEM)and Hongqili(HQL)*** eastward Eulerian transport is enhanced in the WS and west channel(WC),resulting in a higher SSC *** reclamation of Longxue Island(LXI)increases SSC on its east side and east shoal(ES)but decreases the SSC on its west and south ***,in the WC,the estuarine turbidity maximum(ETM)is located near the saltwater wedge and moves southward,which is caused by the southward movement of the maximum longitudinal Eulerian *** neap tide,the changes are similar but relatively *** the other hand,in spring tide,the change in bathymetry makes the SSC in the WS increase,and the area of SSC greater than 100 mg/L increases by 11.4%and expands eastward and southward,which is caused by the increases in wave-induced bottom stress and eastward Eulerian *** the east side of the WC,the eastward Eulerian transport decreases significantly,resulting in a smaller SSC in the middle shoal(MS).In addition,in the WC,the maximum SSC is reduced,which is caused by the smaller wave-induced bottom stress and a significant increase of 109.88%in southward Eulerian *** results in neap tide are similar to those in spring tide but with smaller changes,and the sediment transports northward in the WC owing to the northward Eulerian transport and

关键词： suspended sediment concentration wave bottom stress estuarine turbidity maximum numerical model Zhujiang(Pearl)River Estuary

Visual object tracking- classical and contemporary approaches

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Frontiers of Computer Science 2016年第1期10卷 167-188页

作者： Ahmad ALI Abdul JALIL jianwei niu Xiaoke ZHAO Saima RATHORE Javed AHMED Muhammad AKSAM IFTIKHAR Department of Computer and Information Sciences Pakistan Institute of Engineering & Applied Sciences Islamabad 44000 Pakistan State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing 100191 China Department of Electrical (Telecom) Engineering NUST Military College of Signals Islamabad 44000 Pakistan COMSATS Institute of Information Technology Lahore 54000 Pakistan

Visual object tracking （VOT） is an important sub- field of computer vision. It has widespread application do- mains, and has been considered as an important part of surveillance and security system. VOA facilitates finding the position of target in image coordinates of video frames. While doing this, VOA also faces many challenges such as noise, clutter, occlusion, rapid change in object appearances, highly maneuvered （complex） object motion, illumination changes. In recent years, VOT has made significant progress due to availability of low-cost high-quality video cameras as well as fast computational resources, and many modern techniques have been proposed to handle the challenges faced by VOT. This article introduces the readers to 1） VOT and its applica- tions in other domains, 2） different issues which arise in it, 3） various classical as well as contemporary approaches for object tracking, 4） evaluation methodologies for VOT, and 5） online resources, i.e., annotated datasets and source code available for various tracking techniques.

关键词： visual object tracking computer vision imageprocessing point tracking kernel tracking silhouette track-ing

Real-time haptic model for soft tissue deformation in surgery simulation

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High Technology Letters 2013年第3期19卷 233-239页

作者：孙伟 Zhu Jiandong Zhang Xiaorui Zhao Xinping niu jianwei Song Aiguo School of Information and Control Nanjing University of Information Science & Technology State Key Laboratory of Virtual Reality Technology and Systems Beihang University School of Instrument Science and Engineering Southeast University

The modelling and simulation of deformable objects is a challenging topic in the field of haptic rendering between human and virtual *** this paper,a novel and efficient layered rhombus-chain-connected haptic deformation model based on physics is proposed for an excellent haptic *** the modelling,the accumulation of relative displacements in every chain structure unit in each layer is equal to the deformation on the virtual object surface,and the resultant force of corresponding springs is equivalent to the external *** layered rhombus-chain-connected model is convenient and fast to calculate,and can satisfy real-time requirement due to its simple *** experiments in virtual human liver based on the proposed model are conducted,and the results demonstrate that our model provides stable and realistic haptic feeling in real ***,the display result is vivid.

关键词： human-computer interaction deformable objects haptic rendering feedbackforce virtual reality

Virtual brain surgery simulation system based on haptic interaction

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High Technology Letters 2015年第2期21卷 185-191页

作者：张小瑞 Zhu Jiandong Sun Wei Norman I.Badler Song Aiguo niu jianwei Liu Jia School of Computer and Software Nanjing University of Information Science & Technology Jiangsu Engineering Center of Network Monitoring Nanjing University of Information Science and Technology School of Information and Control Nanjing University of Information Science & Technology School of Engineering and Applied Science University of Pennsylvania School of Instrument Science and Engineering Southeast University State key Laboratory of Virtual Reality Technology and Systems Beihang University

To improve the accuracy and interactivity of soft tissue delormatlon simulation, a new plate spring model based on physics is proposed. The model is parameterized and thus can be adapted to simulate different organs. Different soft tissues are modeled by changing the width, number of pieces, thickness, and length of a single plate spring. In this paper, the structural design, calcula- tion of soft tissue deformation and real-time feedback operations of our system are also introduced. To evaluate the feasibility of the system and validate the model, an experimental system of haptic in- teraction, in which users can use virtual hands to pull virtual brain tissues, is built using PHANTOM OMNI devices. Experimental results show that the proposed system is stable, accurate and promising for modeling instantaneous soft tissue deformation.

关键词： haptic feedback human-computer interaction surgery simulation soft tissue deformation

干煤粉气化炉烧嘴偏置角度变化下的烧嘴罩性能优化研究

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煤化工 2024年第2期52卷 12-14,58页

作者：康建邦张克李志强许冬亮吴平王高峰牛建伟华能(天津)煤气化发电有限公司天津300452

介绍了华能公司IGCC机组干煤粉气化工艺,针对干煤粉气化炉一段烧嘴水平偏置改造后,产渣量大幅提升,导致烧嘴罩发生漫渣、泄漏的问题,通过采取提高烧嘴罩探入深度、优化配煤方式控制气化炉产渣量、改造粉煤给料罐底锥稳定煤线波动等措施... 详细信息

介绍了华能公司IGCC机组干煤粉气化工艺,针对干煤粉气化炉一段烧嘴水平偏置改造后,产渣量大幅提升,导致烧嘴罩发生漫渣、泄漏的问题,通过采取提高烧嘴罩探入深度、优化配煤方式控制气化炉产渣量、改造粉煤给料罐底锥稳定煤线波动等措施,进一步提升了烧嘴罩运行的稳定性,基本避免了烧嘴罩发生漫渣、泄漏现象。

关键词：干煤粉气化炉烧嘴罩烧嘴偏置改造底锥漫渣

基于移动机器人的无线传感器网络高效广播策略

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机械工程学报 2017年第21期53卷 16-23页

作者：吴少波丑武胜牛建伟北京航空航天大学虚拟现实技术与系统国家重点实验室北京100191 北京航空航天大学机械工程及自动化学院北京100191 北京航空航天大学计算机学院北京100191

广播是无线传感器网络一项重要的操作,而网络中节点能量通常受限且通信链路不稳定。针对低占空比传感器网络中引入机器人作为可移动汇点的场景,设计了考虑延迟和能耗的高效广播策略。首先采用最小覆盖圆算法,寻找最优广播位置。然后提... 详细信息

广播是无线传感器网络一项重要的操作,而网络中节点能量通常受限且通信链路不稳定。针对低占空比传感器网络中引入机器人作为可移动汇点的场景,设计了考虑延迟和能耗的高效广播策略。首先采用最小覆盖圆算法,寻找最优广播位置。然后提出了一种延迟约束的高能效广播树算法(DCEBT)。DCEBT在构造广播树时,使用新的量度来充分利用无线广播特性减小能耗,同时基于地理位置对节点进行延迟约束。结果表明,利用机器人的移动性优化广播位置可改善广播性能。而和目前常用的方法相比,DCEBT在保持延迟性能相当的条件下,能大幅提高能量效率。

关键词：无线传感器网络移动汇点广播能量效率延迟