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AIAA Modeling and Simulation Technologies Conference, 2016

作者： Ding, Jianzhong Wang, Chunjie School of Mechanical Engineering and Automation Beihang University Xueyuan Road No.37 Haidian District Beijing100191 China State Key Laboratory of Virtual Reality Technology and Systems and School of Mechanical Engineering and Automation Beihang University Xueyuan Road No.37 Haidian District Beijing100191 China

ISBN: (数字)9781624103872

ISBN: (纸本)9781624103872

A Large amount of dynamics analysis work should be done to predict the landing performance of a specific lunar lander before it really lands on the lunar surface and the modeling procedure turns to be repetitive and time-consuming. To shorten the modeling period and improve the analysis efficiency, an attempt of fast modeling is discussed. In this proposed approach, the lunar-landing system, which consists of components of the landing vehicle, the virtual lunar surface and landing conditions, is completely parameterized to integrate to realize the automation of the modeling process. The parameterization of the landing system is discussed in detail for a precise integration. Using the integrated system, various landing models can be got automated by simply adjusting some parameter values. The prototype used for parameterization is the typical legged lunar lander, and by means of integration, the automation of landing dynamics analysis is realized, making great progress in efficiency improvement. © 2016, American institute of Aeronautics and Astronautics Inc. All rights reserved.

关键词： Landing

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An Improved Vascular Model Based on Mass Spring Model and Parameters Optimization by Gaussian Processes

An Improved Vascular Model Based on Mass Spring Model and Pa...

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IEEE International Conference on Mechatronics and Automation

作者： Dongmei Wu Chaoshun Lv Yidong Bao State Key Laboratory of Robotics and Systems Harbin Institute of Technology Harbin Heilongjiang 150080 China

ISBN: (纸本)9781509023974

This paper built an improved vascular model based on mass spring model, considering forces associated with springs elongation and bending. Meanwhile, for the improve of real-time computation, few nodes are used to build vascular model. In order to ensure vascular model is similar with biomechanics properties of real vascular, using Gaussian Processes to optimize parameters of model. Parameter set which can make model stable is obtained by Gaussian Process Classification and optimal parameter configuration is found by Gaussian Process Regression. A method is proposed for touch detection and force distribution between vascular model and virtual instrument. The method has been implemented in a system including a force feedback device by experiment.

关键词： Surgery simulation vascular model Gaussian Processes force feedback

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Airborne SAR and optical image fusion based on IHS transform and joint non-negative sparse representation

Airborne SAR and optical image fusion based on IHS transform...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Chunhui Liu Yue Qi Wenrui Ding State Key Laboratory of Virtual Reality Technology and System Beihang University Beijing China Research Institute of Unmanned Aerial Vehicle Beihang University Beijing China

ISBN: (纸本)9781509033331

In this paper, a novel airborne synthetic aperture radar (SAR) and optical image fusion method based on Intensity-Hue-Saturation (IHS) and joint non-negative sparse representation (JNNSR) is proposed. Firstly, the color optical image is transformed into IHS space. Then, the intensity component of the optical image and the SAR image are decomposed by JNNSR into common component and innovation components. Based on the non-negative property of the sparse coefficients, the innovation component of the SAR image is fused with the intensity component of the optical image. Finally, the fused result is obtained by performing inverse IHS transform. The experimental result shows that our method is superior to the traditional methods in terms of several universal quality evaluation indexes, as well as in the visual quality.

关键词： Dictionaries Optical imaging Optical sensors Image fusion Transforms Synthetic aperture radar Adaptive optics

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OnSeS: A Novel Online Short Text Summarization Based on BM25 and Neural Network

OnSeS: A Novel Online Short Text Summarization Based on BM25...

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2016 IEEE Global Communications Conference (GLOBECOM)

作者： Jianwei Niu Qingjuan Zhao Lei Wang Huan Chen Mohammed Atiquzzaman Fei Peng State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China School of Computer Science University of Oklahoma Norman OK USA Shanghai Research Institute of Aerospace Computer Technology Shanghai China

ISBN: (纸本)9781509013296

The last decade has witnessed a dramatic growth of social networks, such as Twitter, Sina Microblog, etc. Messages/short texts on these platforms are generally of limited length, causing difficulties for machines to understand. Moreover, it is rarely possible for users to read and understand all the content due to the large quantity. So it is imperative to cluster and extract the viewpoints of these short texts. To solve this, the representation of a word is enriched with additional features from external, but it is demanding in terms of computational and time resources. In this paper, we proposed OnSeS, a novel short text summarization method which makes full use of word2vec to represent a word and utilizes neural network model to generate each word of the summary. OnSeS consists of three phrases: 1) clustering short texts using the K-means algorithm; 2) ranking content of each cluster by building a graph-based ranking model using BM25; 3) generating main point of each cluster with the help of neural machine translation model on the top ranked sentence. The experimental results reveal that our proposed fully data-driven approach outperforms state-of-the-art method.

关键词： Clustering algorithms Natural language processing Feature extraction Machine learning Neural networks Solid modeling Semantics

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Dynamics Analysis of Bionic Parallel Joint Mechanism for the Snake Robot

Dynamics Analysis of Bionic Parallel Joint Mechanism for the...

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第35届中国控制会议

作者： Chuncheng Wu Zhengcai Cao Qing Xiao Yili Fu Key Laboratory of Symbolic Computation and Knowledge Engineering of Ministry of Education Jilin University State Key Laboratory of Robotics and Systems Harbin Institute of Technology College of Information Science and Technology Beijing University of Chemical Technology

ISBN: (纸本)9781509009107

Joint mechanism is a key factor for a snake robot adjusting its postures adapted to clutter environments in search and rescue *** joint mechanisms in prior research simply consist of serially connected revolute joints,which are lack of great load carrying *** nature snake structure,a modular bionic parallel joint mechanism(BPJM) is proposed for the rescue snake *** analysis of the BPJM is necessary for its optimal design and control,providing the force and constraint that must be resisted by joints,links and *** reduce the dynamics computation load,Newton equation and Euler equation are combined by synchronizing the inertial force and inertial moment with the aid of screw ***,the dynamics equations for moving platform and links are formulated in a simplified *** friction at the joints and external force acting on BPJM,which actually affect the motion,are both considered in the ***,the virtual prototype is provided in order to visualize the joint mechanism and the numerical results from the dynamics analysis are given.

关键词： Rescue snake robot Dynamics analysis Bionic parallel joint mechanism Screw theory Newton method

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RETRACTED: Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES

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Journal of Biomedical Informatics 2016年 60卷 410-421页

作者： Jun J. Pan Woojin Ahn Saurabh Dargar Tansel Halic Bai C. Li Ganesh Sankaranarayanan Kurt Roberts Steven Schwaitzberg Suvranu De State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China Center for Modeling Simulation and Imaging in Medicine Rensselaer Polytechnic Institute Troy USA Computer Science Department University of Central Arkansas Conway USA Gastrointestinal Surgery Yale School of Medicine Yale University New Heaven USA Department of Surgery Cambridge Health Alliance Harvard Medical School Boston USA

This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://***/locate/withdrawalpolicy ). This article has been retracted at the request of the Editor-in-Chief. The Publisher and Editor have been informed that the article was submitted to the journal without the consent of all the coauthors. The coauthor Suvranu De expressed concerns regarding the validity of some of the techniques and data reported in the paper, particularly in Figure 18 and Table 3. In addition, we identified in the article a significant portion of copied text that came from the following publications: Metaballs-based physical modeling and deformation of organs for virtual surgery Junjun Pan, Chengkai Zhao, Xin Zhao, Aimin Hao, Hong Qin The Visual Computer , June 2015, Volume 31, Issue 6, pp 947–957 DOI: 10.1007/s00371-015-1106-y virtual reality training and assessment in laparoscopic rectum surgery Jun J. Pan, Jian Chang, Xiaosong Yang, Hui Liang, Jian J. Zhang, Tahseen Qureshi, Robert Howell and Tamas Hickish The International Journal of Medical robotics and Computer Assisted Surgery , Volume 11, Issue 2, pages 194–209 DOI: 10.1002/rcs.1582 As such, this article represents an abuse of the scientific publishing system, which we believe warrants the retraction of the article. The scientific community takes a very strong view on this matter and apologies are offered to the readers of the journal that our processes, which have since been updated, did not adequately verify the assent of the coauthors and their approval of the paper’s content.

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Smoke Simulation with User Specified Details

Smoke Simulation with User Specified Details

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2015 IEEE International Conference on Computer and Communications(ICCC 2015)

作者： Yinbo Han Qing Zuo Yue Qi State Key Laboratory of Virtual Reality Technology and Systems （Beihang University）

Fluid flowing with small-scale details is involved in many games or animation effects. This paper aims to add such small-scale details to fast smoke simulation. In the paper, the whole smoke motion is divided into two parts: a low-resolution motion field and a high-resolution detail motion field, both of which are handled respectively and then combined with each other. The low-resolution motion field is obtained by physical simulation, during which the velocity field is stored and calculated on a coarse grid. The high-resolution detail motion field is gained through two ways. The first is by texture synthesis from an input example texture. The second is translating a small image containing simple contours to a detailed motion field. In both ways, the generation of detail motion field needs to be done only once before the lowresolution motion simulation, while the combination is executed each frame during smoke simulation. In the paper, experiments with varieties of inputs are made on twodimension grids. Results have shown the method introduced in this paper feasible and efficient.

关键词： smoke simulation motion field texture synthesis simple contours

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A spaceborne WAS-GMTI mode based on azimuth multi-channels

A spaceborne WAS-GMTI mode based on azimuth multi-channels

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IET International Radar Conference 2015

作者： Zheng, Shichao Niu, Jianwei Wang, Hui Han, Xiaolei State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China Institute of Electronics Chinese Academy of Sciences Beijing China Beijing Institute of Spacecraft System Engineering Beijing China

ISBN: (纸本)9781849199940

In this paper, the spaceborne wide-area surveillance ground moving target indication (WAS-GMTI) mode is proposed. In the proposed mode, the requirement of detecting targets from different aspect angles with a high revisit rate can be achieved by modifying the TOPS mode which steers antenna in the azimuth direction. And a three-channel system is chosen to achieve fine GMTI performance. With the three-channel system, the detection of moving targets is realized by displaced phase center antenna (DPCA) technique and the motion parameter is estimated using the interferometric phase. The feasibility of the proposed mode as well as the performance of GMTI is validated by theoretical analysis and simulation experiments.

关键词： Synthetic aperture radar

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Graphic and haptic simulation for transvaginal cholecystectomy training in NOTES

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Journal of Biomedical Informatics 2016年 60卷 410-421页

作者： Pan, Jun J. Ahn, Woojin Dargar, Saurabh Halic, Tansel Li, Bai C. Sankaranarayanan, Ganesh Roberts, Kurt Schwaitzberg, Steven De, Suvranu State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China Center for Modeling Simulation and Imaging in Medicine Rensselaer Polytechnic Institute Troy United States Computer Science Department University of Central Arkansas Conway United States Gastrointestinal Surgery Yale School of Medicine Yale University New Heaven United States Department of Surgery Cambridge Health Alliance Harvard Medical School Boston United States

Background: Natural Orifice Transluminal Endoscopic Surgery (NOTES) provides an emerging surgical technique which usually needs a long learning curve for surgeons. virtual reality (VR) medical simulators with vision and haptic feedback can usually offer an efficient and cost-effective alternative without risk to the traditional training approaches. Under this motivation, we developed the first virtual reality simulator for transvaginal cholecystectomy in NOTES (VTEST™). Methods: This VR-based surgical simulator aims to simulate the hybrid NOTES of cholecystectomy. We use a 6DOF haptic device and a tracking sensor to construct the core hardware component of simulator. For software, an innovative approach based on the inner-spheres is presented to deform the organs in real time. To handle the frequent collision between soft tissue and surgical instruments, an adaptive collision detection method based on GPU is designed and implemented. To give a realistic visual performance of gallbladder fat tissue removal by cautery hook, a multi-layer hexahedral model is presented to simulate the electric dissection of fat tissue. Results: From the experimental results, trainees can operate in real time with high degree of stability and fidelity. A preliminary study was also performed to evaluate the realism and the usefulness of this hybrid NOTES simulator. Conclusions: This prototyped simulation system has been verified by surgeons through a pilot study. Some items of its visual performance and the utility were rated fairly high by the participants during testing. It exhibits the potential to improve the surgical skills of trainee and effectively shorten their learning curve. © 2016 Elsevier Inc.

关键词： virtual reality

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Real-time RTI development based on combined message and task scheduling

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Journal of Computational Information systems 2015年第5期11卷 1817-1824页

作者： Liu, Shutian Feng, Ce Dai, Shuling State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing China Flight Theory Department Naval Aviation Institute Huludao China

In order to improve the real-time performance of DVE (Distributed virtual Environment) under RTI (Run-Time Infrastructure), it is essential to ensure the determinacy of response of tasks communicating between federates in a time-bounded network. Precedence constraints are produced between tasks of different federates because of communicating, so combined scheduling of message and task must be considered. The objective of this paper is to develop a scheme that allows for the dynamic scheduling of local tasks and communication completed before their deadlines. Precedence constraints are converted into a communicating template, enabling efficient on-line processing. The EDF (Earliest Deadline First) scheduling operates in parallel involved in DVE, further obtaining efficiency. The simulation results show that the scheme can handle the combined scheduling of tasks and messages effectively and consequently improve the real-time performance of RTI. Copyright © 2015 Binary Information Press.

关键词： Scheduling

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