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Microscopic view of phytoplankton along the Yangtze River

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Science China(Technological Sciences) 2019年第11期62卷 1873-1884页

作者： LIU YuXin XU XuMing WANG Ting NI JinRen Key Laboratory of Water and Sediment Sciences Ministry of EducationCollege of Environmental Sciences and EngineeringPeking University

Phytoplankton play an important role in nutrient cycling and energy conversion. However, phytoplankton community is poorly understood in large river ecosystems. Based on the large-scale samplings conducted in spring and autumn of 2017, a systematic study has been made on seasonal and spatial distributions of phytoplankton community along the mainstream of the Yangtze River. As results, 6 phyla were identified and 59 phytoplankton species were detected using microscopy, including Bacillariophyta(29 species), Chlorophyta(13 species) and Cyanophyta(8 species) as the dominant group. Moreover, the density of phytoplankton was ranged 0.05×10^6–1.90×10^6 cells/L and the biomass was 0.01–1.01 mg/L, both reaching their maximum in the middle reach from Yichang to Wuhan. Significant seasonal difference of phytoplankton community was observed and spatial dissimilarity in spring was revealed. The cell abundance and biomass of phytoplankton could be fairly estimated by chlorophylla, and redundancy analysis indicated that water temperature, dissolved oxygen, biochemical oxygen demand, nitrite, and ammonia nitrogen were the most important explanatory environmental factors for phytoplankton compositions in the Yangtze River.

关键词： microscopic view phytoplankton community spatiotemporal distribution Yangtze River environmental factor

Three-dimensional free view reconstruction in axially distributed image sensing

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Chinese Optics Letters 2017年第8期15卷 40-43页

作者： chang-taek seo shin-won kang myungjin cho 3d display components support center gumi electronics and information technology research instituteGumi-siGyeongsangbuk-do 730-853Korea school of electronics engineering college of it engineeringkyungpook national universityDaegu 702-701Korea department of electrical electronicand control engineeringiitchankyong national university327 Chungang-roAnseong-siGyonggi-do 456-749Korea

Three-dimensional （3D） acquisition has been the most important technique for augmented reality or virtual reality industries. Stereo vision can obtain 3D infor- mation of objects using disparity between two images captured by a stereo camera. However, due to lack of per- spectives for 3D objects in this technique, accurate 3D information may not be generated and the number of viewing points is limited. By contrast, multi-view or super multi-view imaging techniques can obtain more accurate 3D information because they use multiple cameras for pickup of 3D objects so that more perspec- tives and viewing points of 3D objects can be recorded.

关键词： view free Three-dimensional free view reconstruction in axially distributed image sensing

Structure and deformation measurements of shallow overburden during top coal caving longwall mining

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International Journal of Mining Science and Technology 2017年第6期27卷 1081-1085页

作者： Li Sheng Fan Chaojun Luo Mingkun Yang Zhenhua Lan Tianwei Zhang Haifeng College of Mining Liaoning Technical University State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines Henan Polytechnic University State Key Laboratory of Coal Resources and Safe Mining China University of Mining & Technology Chengyi Coal Mine Inner Mongolia Yitai Coal Co.Ltd.

Mining induced pressures are strong and overburden failure areas are large in top coal caving longwall mining, which constrains high production and safety mining. By employing the combination of the full view borehole photography technique and the seismic CT scanner technique, the deformation and failure of overlying strata of fully mechanized caving face in shallow coal seam were studied and the failure development of overburden was determined. Results show that the full view borehole photography can reveal the characteristics of strata, and the seismic CT scanner can reflect the characteristics of strata between the boreholes. The combined measurement technique can effectively determine the height of fractured and caved zones. The top end of the caved zone in Yangwangou coal mine employing the top coal caving longwall mining was at the depth of 171 m and fractured zone was at the depth of 106-110 m. The results provide a theoretic foundation for controlling the overburden strata in the shallow buried top coal caving panel.

关键词： Top coal caving Shallow depth Overburden failure and deformation Full view borehole photography Seismic CT scanner

New color correction method for multi-view video using disparity vector information

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Chinese Optics Letters 2008年第9期6卷 654-656页

作者：符冉迪邵枫蒋刚毅郁梅 Faculty of Information Science and Engineering Ningbo University

Color inconsistency is an urgent problem to be solved in free viewpoint television. In this letter, a new color correction method is proposed by using disparity vector information. At first, we separate foreground and background from the scene with a method of mean-removed disparity estimation. Then the correction parameters are estimated by adopting linear fitting for foreground and background regions, respectively. Next, with expectation-maximization algorithm, we integrate correction parameters of foreground and background to get the final corrected image. Finally, video tracking technique is performed to correct multi-view video. Experimental results show that the proposed method is quite effective.

关键词： view In FTV

Web3D Learning Framework for 3D Shape Retrieval Based on Hybrid Convolutional Neural Networks

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Tsinghua Science and Technology 2020年第1期25卷 93-102页

作者： Wen Zhou Jinyuan Jia Chengxi Huang Yongqing Cheng School of Computer and Information Anhui Normal UniversityWuhu 241002China School of Software Engineering Tongji UniversityShanghai 201804China College of Electronics and Information Engineering Tongji UniversityShanghai 201804China School of Engineering and Computer Science University of HullHullHU6 7RXUK.

With the rapid development of Web3 D technologies, sketch-based model retrieval has become an increasingly important challenge, while the application of Virtual Reality and 3 D technologies has made shape retrieval of furniture over a web browser feasible. In this paper, we propose a learning framework for shape retrieval based on two Siamese VGG-16 Convolutional Neural Networks(CNNs), and a CNN-based hybrid learning algorithm to select the best view for a shape. In this algorithm, the AlexNet and VGG-16 CNN architectures are used to perform classification tasks and to extract features, respectively. In addition, a feature fusion method is used to measure the similarity relation of the output features from the two Siamese networks. The proposed framework can provide new alternatives for furniture retrieval in the Web3 D environment. The primary innovation is in the employment of deep learning methods to solve the challenge of obtaining the best view of 3 D furniture,and to address cross-domain feature learning problems. We conduct an experiment to verify the feasibility of the framework and the results show our approach to be superior in comparison to many mainstream state-of-the-art approaches.

关键词： Web3D sketch-based model retrieval Convolutional Neural Networks(CNNs) best view cross-domain

Global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

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Science China(Technological Sciences) 2010年第3期53卷 595-607页

作者： ZHANG Li1,WANG HuaiLei1 & HU HaiYan1,2 1 MOE Key Lab of Mechanics and Control of Aerospace Structures,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China 2 School of Aerospace Engineering,Beijing Institute of Technology,Beijing 100081,China MOE Key Lab of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and Astronautics Nanjing China School of Aerospace Engineering Beijing Institute of Technology Beijing China

This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback.Based on a detailed analysis of the stability switches of the trivial equilibrium of the system,the stability charts are given in a parameter space consisting of the time delay and the feedback gains.The center manifold reduc-tion and the normal form method are used to study Hopf bifurcations with respect to the time delay.To gain an insight into the persistence of a Hopf bifurcation as the time delay varies farther away from its critical value,the method of multiple scales is used to obtain the global view of Hopf bifurcations with respect to the time delay.Both the analytical results of Hopf bifurca-tions and global view of those bifurcations are validated via a collocation scheme implemented on DDE-Biftool.The most important discovery in this paper is the well-structured global view of Hopf bifurcations for the system of concern,showing the generality of the persistence of Hopf bifurcations.

关键词： Hopf bifurcation global view center manifold reduction method of multiple scales collocation scheme

A review of progress on nano-aperture VCSEL Invited Paper

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Chinese Optics Letters 2008年第10期6卷 748-754页

作者： Sonny Vo James S.Harris Solid State and Photonics Laboratory Stanford UniversityStanfordCalifornia94305USA

This paper reviews the progress on nano-aperture vertical-cavity surface-emitting lasers （VCSELs）. The design, fabrication, and polarization control of nano-aperture VCSELs are reviewed. With the nanoaperture evolving from conventional circular and square aperture to unique C-shaped, H-shaped, I-shaped, and bowtie-shaped aperture, both the near-field intensity and near-field beam confinement from nanoaperture VCSELs are significantly improved. As a high-intensity compact light source with sub-100- nm spot size, nano-aperture VCSELs are promising to realize many new near-field optical systems and applications.

关键词： VCSEL view A review of progress on nano-aperture VCSEL Invited Paper

Large field of view computed laminography with the asymmetric rotational scanning geometry

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Science China(Technological Sciences) 2010年第8期53卷 2261-2271页

作者： FU Jian 1,2 ,JIANG BaiHong&LI Bin 1 School of Mechanical Engineering and Automation,Beihang University,Beijing 100191,China 2 Research Center of Digital Radiation Imaging and Biomedical Imaging,Beihang University,Beijing 100191,China School of Mechanical Engineering and Automation Beihang University Beijing China Research Center of Digital Radiation Imaging and Biomedical Imaging Beihang University Beijing China

X-ray computed laminography(CL)is used in the fields of industrial inspection and medical imaging.It can provide the internal structure three-dimensional(3D)information of a region of the objects nondestructively.It is important to the clinical diagnosis and the quality control of flat objects like printed circuit boards,aircraft wings and satellite solar panels.With the restriction that the imaging region must be within the X-ray beam formed by the X-ray source and the detector,the imaging field of view of CL is limited by the size of detector.A new CL method with an asymmetric rotational cone-beam scanning geometry,called large field of view CL,is presented to overcome the existing disadvantage.It can extend the imaging region when the imaging spatial resolution keeps the same as that of the conventional CL.It can also improve the imaging spatial resolution when the imaging region keeps the same as that of the conventional CL.The asymmetric configuration can be achieved by offsetting the detector from the conventional symmetric configuration.It does not,however,require new detectors and X-ray source nor alter the scanning mechanical system.The filtered back-projection(FBP)reconstruction algorithm and the data truncation smoothing functions have been deduced to reconstruct the images directly from the data acquired with this asymmetric configuration.We performed numerical studies and experiments to demonstrate and validate the proposed approach. Results in these studies and experiments confirm that the proposed method can enlarge the imaging region and improve the spatial resolution.The proposed approach may find applications in the CL system with the rotational scanning geometry.

关键词： computed laminography image reconstruction reconstruction algorithm imaging field of view imaging spatial resolution

Conceptual model of real-time IoT systems

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Frontiers of Information Technology & Electronic Engineering 2019年第11期20卷 1457-1464页

作者： Bo YUAN De-ji CHEN Dong-mei XU Ming CHEN Department of Computer Science and Technology Tongji UniversityShanghai 201804China School of Electronics and Information Engineering Jinggangshan UniversityJi'an 343009China MOE Key Laboratory of Embedded System and Service Computing Tongji UniversityShanghai 201804China China Electronics Standardization Institute Beijing 100007China Chinesisch-Deutsche Hochschule for Angewandte Wissenschaften Tongji UniversityShanghai 201804China

We address a special kind of Internet of Things (IoT) systems that are also real-time. We call them real-time IoT (RT-IoT) systems. An RT-IoT system needs to meet timing constraints of system delay, clock synchronization, deadline, and so on. The timing constraints turn to be more stringent as we get closer to the physical things. Based on the reference architecture of IoT (ISO/IEC 30141), the RT-IoT conceptual model is established. The idea of edge subsystem is introduced. The sensing & con-trolling domain is the basis of the edge subsystem, and the edge subsystem usually must meet the hard real-time constraints. The model includes four perspectives, the time view, computation view, communication view, and control view. Each view looks, from a different angle, at how the time parameters impact an RT-IoT system.

关键词： Internet of Things(IoT) Real-time system Conceptual model view Hard/Soft real-time