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Exploiting AML algorithm for multiple acoustic source 2D and 3D DOA estimations

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控制理论与应用（英文版） 2011年第1期9卷 34-43页

作者： Juo-Yu LEE ralph E. HUDSON Kung YAO Electrical Engineering Department University of CaliforniaLos AngelesCalifornia 90095-1594U.S.A.

The approximate maximum likelihood (AML) algorithm shows promises for joint estimations of acoustic source spectrum and direction-of-arrival (DOA). For the multisource case, the AML algorithm remains feasible as one considers an alternating projection procedure based on sequential iterative search on single source parameters. In order to perform multisource beamforming operations, earlier, we used a two-dimensional (2D) sensor array with 2D AML to obtain the DOA estimations for sources in the far field of the array. Now, the 3D AML algorithm enables a 3D sensor array to collect acoustic data for estimation of DOA represented in azimuth and elevation angles. In this paper, we consider two acoustic sources being simultaneously active and derive Crame′r-Rao bound (CRB) on DOA estimation given by a 3D array. Also, we compare the two-source DOA estimation results of 2D AML and 3D AML, respectively. To construct reasonable constraints on sensor topology, we adopt the concept of isotropic array and decouple the interplay between azimuth and elevation angle variations. The 3D AML algorithm exhibits superior spatial separation over its 2D counterpart for multiple sources located at different azimuth and elevation angles. Although the 3D AML algorithm requires more demanding computational complexity, we have developed a number of efficiency enhancements to reduce the loading for the grid search.

关键词： Approximate maximum likelihood Direction-of-arrival Alternating projection procedure

Panorama completion for street views

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Computational Visual Media 2015年第1期1卷 49-57页

作者： Zhe Zhu ralph R.Martin Shi-Min Hu TNLIST Department of Computer Science and Technology Tsinghua University School of Computer Science & Informatics Cardiff University

This paper considers panorama images used for street views. Their viewing angle of 360° causes pixels at the top and bottom to appear stretched and warped. Although current image completion algorithms work well, they cannot be directly used in the presence of such distortions found in panoramas of street views. We thus propose a novel approach to complete such 360° panoramas using optimizationbased projection to deal with distortions. Experimental results show that our approach is efficient and provides an improvement over standard image completion algorithms.

关键词： image completion panorama street views structure-rectifying warp

Harmonic Field Based Volume Model Construction from Triangle Soup

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Journal of Computer Science & Technology 2010年第3期25卷 562-571页

作者：沈超慧张国鑫来煜坤胡事民 ralph R. Martin Tsinghua National Laboratory for Information Science and Technology Department of Computer Science and Technology Tsinghua University School of Computer Science Cardiff University

Surface triangle meshes and volume data are two commonly used representations of digital geometry. Converting from triangle meshes to volume data is challenging, since triangle meshes often contain defects such as small holes, internal structures, or self-intersections. In the extreme case, we may be simply presented with a set of arbitrarily connected triangles, a ＂triangle soup＂. This paper presents a novel method to generate volume data represented as an octree from a general 3D triangle soup. Our motivation is the Faraday cage from electrostatics. We consider the input triangles as forming an approximately closed Faraday cage, and set its potential to zero. We then introduce a second conductor surrounding it, and give it a higher constant potential. Due to the electrostatic shielding effect, the resulting electric field approximately lies in that part of space outside the shape implicitly determined by the triangle soup. Unlike previous approaches, our method is insensitive to small holes and internal structures, and is observed to generate volumes with low topological complexity. While our approach is somewhat limited in accuracy by the requirement of filling holes, it is still useful, for example, as a preprocessing step for applications such as mesh repair and skeleton extraction.

关键词： volume model triangle soup harmonic field representation conversion mesh repair

Robust tracking-by-detection using a selection and completion mechanism

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Computational Visual Media 2017年第3期3卷 285-294页

作者： Ruochen Fan Fang-Lue Zhang Min Zhang ralph R.Martin Tsinghua University School of Engineering and Computer Science Victoria University of Wellington Center of Mathematical Sciences and Applications Harvard University School of Computer Science and Informatics Cardiff University

It is challenging to track a target continuously in videos with long-term occlusion,or objects which leave then re-enter a *** tracking algorithms combined with onlinetrained object detectors perform unreliably in complex conditions, and can only provide discontinuous trajectories with jumps in position when the object is occluded. This paper proposes a novel framework of tracking-by-detection using selection and completion to solve the abovementioned problems. It has two components, tracking and trajectory completion. An offline-trained object detector can localize objects in the same category as the object being tracked. The object detector is based on a highly accurate deep learning model. The object selector determines which object should be used to re-initialize a traditional tracker. As the object selector is trained online,it allows the framework to be adaptable. During completion, a predictive non-linear autoregressive neural network completes any discontinuous *** tracking component is an online real-time algorithm, and the completion part is an after-theevent mechanism. Quantitative experiments show a significant improvement in robustness over prior stateof-the-art methods.

关键词： object tracking detection proposal selection trajectory completion

Principles of carbon nanotube dielectrophoresis

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Nano Research 2021年第7期14卷 2188-2206页

作者： Wenshan Li Frank Hennrich Benjamin S.Flavel Simone Dehm Manfred Kappes ralph Krupke Institute of Nanotechnology Karlsruhe Institute of TechnologyKarlsruhe 76021Germany Institute of Physical Chemistry Karlsruhe Institute of TechnologyKarlsruhe 76021Germany Institute of Materials Science Technische Universität DarmstadtDarmstadt 64287Germany Institute for Quantum Materials and Technologies Karlsruhe Institute of TechnologyKarlsruhe 76021Germany School of Mechanical Engineering Shanghai Jiao Tong UniversityNo.800 Dongchuan RoadShanghai 200240Chin

Dielectrophoresis(DEP)describes the motion of suspended objects when exposed to an inhomogeneous electric *** has been successful as a method for parallel and site-selective assembling of nanotubes from a dispersion into a sophisticated device *** have conducted extensive works to understand the DEP of nanotubes in aqueous ionic surfactant ***,only recently,DEP was applied to polymer-wrapped single-walled carbon nanotubes(SWCNTs)in organic solvents due to the availability of ultra-pure SWCNT *** this paper,the focus is on the difference between the DEP in aqueous and organic *** starts with an introduction into the DEP of carbon nanotubes(CNT-DEP)to provide a comprehensive,in-depth theoretical background before discussing in detail the experimental procedures and *** academic interests,this work focuses on the CNT-DEP deposition scheme,discusses the importance of the electrical double layer,and employs finite element simulations to optimize CNT-DEP deposition condition with respect to the experimental *** important outcome is an understanding of why DEP in organic solvents allows for the deposition and alignment of SWCNTs in low-frequency and even static electric fields,and why the response of semiconducting SWCNTs(s-SWCNTs)is strongly enhanced in non-conducting,weakly polarizable *** to further improve CNT-DEP for s-SWCNT-relevant applications are given as ***,this work should serve as a practical guideline to select the appropriate setting for effective CNT DEPs.

关键词： single-walled carbon nanotubes hydrodynamics assembly deposition alignment polarizability dielectrophoresis

Responses to defoliation and fertiliser,corm development and chemical control of onion grass(Romulea rosea)in the Mediterranean environment of southern Australia

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Grassland Research 2022年第3期1卷 197-206页

作者： Zhongnan Nie Reto Zollinger ralph Behrendt Department of Jobs Precincts and RegionsHamiltonVictoriaAustralia College of Grassland ScienceGansu Agricultural UniversityLanzhouGansu ProvinceChina

Background:Onion grass(Romulea rosea)is a common weed that infests native and improved pastures in the Mediterranean environments of southern *** is a very challenging weed to control due to its distinctive growth and survival mechanisms involving ***:Three glasshouse experiments were conducted in Australia to investigate the response of onion grass to defoliation and fertiliser application,the development and growth of onion grass corms and the chemical control of the weed in winter and ***:Defoliating consistently to 1 cm above ground reduced corm weight by 84%compared with the *** or high fertiliser application did not increase herbage mass of onion grass compared with the nonfertilised *** corm weight of onion grass declined from Weeks 1 to 8 after emergence,remained at 53-60 mg dry matter(DM)corm−1 from Weeks 8 to 19 and then declined on average to 37mgDMcorm−1 up to Week 26 after *** corms started to develop at Week 6 after emergence.A small proportion of the onion grass plants(7.5%)developed multiple new corms(3-6 corms)from a single old *** most effective herbicide control was a winter application of metsulfuron methyl or imazamox as an alternative product to protect ***:This study has identified the growth and development patterns of onion grass corms,how the plant responded to defoliation and fertiliser application and effective chemical control of this *** findings have significant practical implications for the improvement of onion grass-infested pastures.

关键词： corm development herbicide plant density seedpod number timing of chemical control

Cancer stem cells, stemness markers and selected drug targeting: metastatic colorectal cancer and cyclooxygenase-2/prostaglandin E2 connection to WNT as a model system

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Journal of Cancer Metastasis and Treatment 2019年第1期4卷 18-40页

作者： Reem Ali ALHulais Stephen John ralph School of Medical Sciences Griffith University Menzies Health Institute Queensland Gold Coast QLD 4222 Australia

Few studies have reported on the analyses of drugs targeting enriched populations of cancer stem cells (CSCs) as a means for identifying potent anti-CSC agents. This review evaluates recent information on the identification and functions of specific CSC surface markers, with particular emphasis on colorectal cancers and the screening of drugs to eliminate such cells. Many of these CSC markers are found commonly expressed on CSCs from different cancer types as well as embryonic stem cells. These markers are often related to hypoxic activation of the WNT/b-catenin pathway, cyclooxygenase-2/prostaglandin E signalling and their relationship to LGR5. By effectively using drugs that inhibit these pathways to kill the CSC population, or otherwise forcing them out of dormancy into active cell division, cancers should become more susceptible to chemotherapy. Such combinational therapies targeting both CSCs and proliferating tumor cells should greatly improve upon the current basis for treatment.

关键词： Cancer stem cells colorectal cancer markers selective drug targeting

3D modeling and motion parallax for improved videoconferencing

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Computational Visual Media 2016年第2期2卷 131-142页

作者： Zhe Zhu ralph R.Martin Robert Pepperell Alistair Burleigh TNList Tsinghua University School of Computer Science & Informatics Cardiff University Cardiff School of Art & Design Cardiff Metropolitan University

We consider a face-to-face videoconferencing system that uses a Kinect camera at each end of the link for 3D modeling and an ordinary2 D display for output. The Kinect camera allows a 3D model of each participant to be transmitted;the(assumed static) background is sent ***, the Kinect tracks the receiver's head,allowing our system to render a view of the sender depending on the receiver's viewpoint. The resulting motion parallax gives the receivers a strong impression of 3D viewing as they move, yet the system only needs an ordinary 2D display. This is cheaper than a full3 D system, and avoids disadvantages such as the need to wear shutter glasses, VR headsets, or to sit in a particular position required by an autostereo *** studies show that users experience a greater sensation of depth with our system compared to a typical 2D videoconferencing system.

关键词： naked-eye 3D motion parallax videoconferencing real-time 3D modeling

Predicting erosion and sediment yield in a mesoscale basin in the semiarid monsoon region Miyun/China

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Ecological Processes 2014年第1期3卷 214-224页

作者： Michael Gebel Mario Uhlig Stefan Halbfass ralph Meissner Shuhuai Duan Gesellschaft für Angewandte Landschaftsforschung(GALF)bR Am Ende 1401277 DresdenGermany Department of Soil Physics Helmholtz Centre for Environmental Research–UFZLysimeter StationDorfstraße 5539615 FalkenbergGermany Beijing Soil and Water Conservation Center(BWA) No.5 Yunuantan South RoadBeijing 100038Haidian DistrictChina

Introduction:Changes in land use and agricultural management have caused a strong increase in sediment and particulate phosphorus input into the Miyun *** simulation of the relevant runoff and sediment fluxes at the mesoscale needs adequate procedures,adapted to a semiarid monsoon climate and regional land-use ***:The modified Universal Soil Loss Equation(USLE-M)was integrated into the STOFFBILANZ model to calculate daily soil losses in the entire Miyun catchment *** results are well within the range of monitoring data from Wischmeier plots that are located inside the investigation *** the reference year 2009,soil erosion was estimated at an average of 952 kg ha^(-1) year^(-1).Daily based simulation of sediment input into surface waters was done in the next step,taking into account the likeliness of sediment input and sediment delivery *** sediment inputs are by 113 kg ha^(-1) year^(-1).Critical source areas are located on cropland and are particularly relevant on the former lakebed of the Miyun reservoir which has recently been used for corn ***:Compared with observation data from the Bai and Chao rivers,the simulation of sediment loads showed a satisfying agreement that underlines the suitability of the selected approach to substitute recently used one-year balances based on the Universal Soil Loss Equation(USLE)*** tillage was selected as a possible mitigation option to reduce soil erosion and sediment *** to the limited availability of spatial and monitoring data,the simulations are approximate and only a first step in contributing to an integrated river basin management that should be improved in future.

关键词： Direct runoff Mesoscale Miyun Model Sediment input Soil erosion STOFFBILANZ