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virtual visualisation-based approach for fighter stealth-coating analysis

Materials Research Innovations 2015年 19卷 46-50页

作者： Geng, J. Lv, C. Guo, Z. Zhou, D. Wang, Z. School of Reliability and Systems Engineering Beijing University of Aeronautics and Astronautics Beijing100191 China State Key Laboratory of Virtual Reality Technology and System Beijing100191 China

This paper presents a novel stealth-coating analysis method based on virtual visualisation technology to provide recommendations for stealthcoating in fighter design and maintenance. The proposed methodology focuses on the inherent property and extrinsic performance of the stealth material and visualises both stealth coating and its performance in a virtual environment according to corresponding material properties. Stealth-coating design or maintenance is then conducted in a predictive manner intuitively and systemically for analysis. A case study on infrared stealth is presented to illustrate the performance of the method. Results show the feasibility of virtual visualisation in improving fighter stealth-coating design. © W. S. Maney & Son Ltd 2015.

关键词： virtual reality

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Speed-accuracy tradeoff of controlling absolute magnitude of fingertip force

Speed-accuracy tradeoff of controlling absolute magnitude of...

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World Haptics Conference

作者： Teng Li Dangxiao Wang Shusheng Zhang Yuru Zhang Chun Yu State Key Lab of Virtual Reality Technology and Systems Beihang University Beijing China Tsinghua Univesity Beijing China

Controlling absolute magnitudes of fingertip force is an important skill in many haptic interactions such as surgical operations and mechanical assemblies. A fundamental question in the force control is how quickly human can output a target force with expected accuracy. In this paper, human's capability to control absolute magnitudes of fingertip force under audio or visual feedback was observed through experiments. Twelve participants applied a target force by pressing a force sensor with their fingers and maintained the force within a specified tolerance for a specific period of time (500ms). The magnitudes of target force and tolerance were manipulated systematically to yield varied levels of task difficulty. The experimental data showed that the applied fingertip force obeyed Fitts' law under both visual and auditory feedback modes when the index of difficulty (ID) was smaller than a threshold. The results may be used as guidelines for the applications that rely on accurate and quick changing force control over a target region such as multiple tapping tasks.

关键词： Force Visualization Force control Time factors Fingers Accuracy Force sensors

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Effect of vibrotactile cues for guiding simultaneous procedural motion of two joints on upper limbs

Effect of vibrotactile cues for guiding simultaneous procedu...

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IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Mu Xu Dangxiao Wang Yuru Zhang Dong Wu State Key Lab of Virtual Reality Technology and Systems Beihang University Beijing China College Beijing Sport University Beijing China

Simultaneous motion control of multiple joints has many potential applications such as Tai Chi, Yoga etc. The capability of vibrotactile cues to assist this kind of motor task has not been well explored. In this paper, we studied the effect of vibrotactile cues for guiding procedural motion of two joints on human's upper limbs. By mounting eight vibrotactile motors on two arms, we performed two experiments to measure human's perception and motor performance in response to the vibrotactile commands. In the first experiment, we measured perceptual performance of correctly identifying the location of two active vibrotactile cues. The difference between sustained, pulsed and hybrid vibration conditions was compared. To explore the possible reasons leading to the wrong perception results, the correct rate was ranked among different combinations of cues. In the second experiment, the correct rate of procedural motion control of two joints was measured, while vibrotactile cues were used as guidance signals to produce the motion command. The results showed that average correct rate of two cues localization on upper limbs was as high as 98%, while the average correct rate of procedural motion control of two joints was only 86%. Further analysis revealed that low correct rate of procedural motion control was caused by the unnatural motion pattern, i.e. two joints on a same arm and rotate in opposite directions.

关键词： Motion control Vibrations Visualization Tactile sensors Haptic interfaces User interfaces Motion measurement

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Performance of simultaneous motion and respiration control under guidance of audio-haptic cues

Performance of simultaneous motion and respiration control u...

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World Haptics Conference

作者： Mu Xu Dangxiao Wang Yuru Zhang Jian Song Dong Wu State Key Lab of Virtual Reality Technology and Systems Beihang University Beijing China Wushu College Beijing Sport University Beijing China

Compared with single-modal sensorimotor task, cross-modal sensorimotor tasks such as Tai Chi are more complex because they require simultaneous control of joint motion and respiration. In this paper, we compared the performance of single and multi-sensory cues in single-modal and cross-modal tasks. The experimental results showed that for single-modal task of two joint motions, the performance of using both audio and vibrotactile cues was slightly worse than that of using single-sensory cues where both joints were guided by vibrotactile cues, which implied that the single-sensory cue was more suitable for the single-modal motor tasks while the multi-sensory cues might produce distraction to participants. For simultaneous control of joint motion and respiration, the multiple sensory cues produced better performance than the single sensory cues. The results implied that multi-sensory cues were more effective than single sensory cues in reducing mental workload when learning complex cross-modal motor tasks.

关键词： Joints Motion control Vibrations Standards Elbow Shoulder Haptic interfaces

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An improved maintenance time prediction method in virtual environment 20

An improved maintenance time prediction method in virtual en...

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20th ISSAT International Conference Reliability and Quality in Design, RQD 2014

作者： Jie, Geng Chuan, Lv Dong, Zhou State Key Laboratory of Virtual Reality Technology and System Beijing University of Aeronautics and Astronautics Beijing China

ISBN: (纸本)9780991057603

In this paper, an improved maintenance time prediction method is proposed to predict maintenance time in virtual environment based on the presented paper in 19thRQD conference sponsored by ISSAT. The improved method focuses on two points to increase the accuracy of prediction: (1) considering more factors in practical maintenance process and classifying the factors for compensation with different principals;(2) analyzing the interrelationship between virtual operation and actual operation and confirming the corresponding compensation time for each factor. The detailed analysis solves the ratio problem between virtual maintenance time and practical maintenance time that mentioned in the former research, and the feedback information on practical maintenance from different domains indicates the proposed method is accurate to a certain extent.

关键词： virtual reality

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Methods of projecting 2D wrinkle curves onto a 3D model

Methods of projecting 2D wrinkle curves onto a 3D model

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International Conference on Machine Tool technology and Mechatronics Engineering, ICMTTME 2014

作者： Lin, Xiao Dan He, Bing Zhang, Xiu Lin State Key Lab of Virtual Reality Technology and Systems Beihang University Beijing China

ISBN: (纸本)9783038352464

Wrinkles make cloth simulation results more realistic. However, generating wrinkles with physically based methods usually requires a computationally expensive simulation, while geometric methods such as deforming the 3D mesh based on predefined curves need time-consuming manual design. In this paper, we extract 2D wrinkle curves from pictures of clothing and project the curves onto a 3D clothing model. Two schemes for projecting 2D curves to the 3D model are presented in the paper, including the brute force method and the acceleration method. The brute force method has excellent projection results and the acceleration method enhances the efficiency of projection process significantly. A quad tree for the 3D model is built up in the acceleration method to improve the efficiency of projection process. © (2014) Trans Tech Publications, Switzerland.

关键词： Efficiency

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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： Shichao Zheng Jianwei Niu Hui Wang Xiaolei Han 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

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： ground moving target indication (GMTI) synthetic aperture radar (SAR) terrain observation by progressive scans (TOPS) wide-area surveillance (WAS) Synthetic aperture radar MULTICHANNEL azimuth ground moving target indication ANTENNA antennae ASPECT ANGLE Theoretical analysis

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Deco: False data detection and correction framework for participatory sensing

Deco: False data detection and correction framework for part...

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International Workshop on Quality of Service

作者： Long Cheng Linghe Kong Chengwen Luo Jianwei Niu Yu Gu Wenbo He Sajal Das State Key Lab of Networking & Switching Tech. Beijing Univ. of Posts & Telecomm. Beijing China State Key Lab of Virtual Reality Technology and Systems Beihang University Beijing China McGill University Canada National University of Singapore Singapore IBM Research Austin USA Missouri University of Science and Technology USA

Participatory sensing enables to collect a vast amount of data from the crowd by allowing a wide variety of sources to contribute data. However, the openness of participatory sensing exposes the system to malicious and erroneous participations, inevitably resulting in poor data quality. This brings forth the important issues of false data detection and correction in participatory sensing. Furthermore, data collected by participants normally include considerable missing values, which poses challenges for accurate false data detection. In this work, we propose DECO, a general framework to detect false values for participatory sensing in the presence of missing data. By applying a tailored spatio-temporal compressive sensing technique, DECO is able to accurately detect the false data and estimate both false and missing values for data correction. We validate our design through an experimental case study.

关键词： Sensors Quality of service IEEE 802.11 Standard Atmospheric measurements Particle measurements Compressed sensing Estimation

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Multi-task rank learning for image quality assessment 40

Multi-task rank learning for image quality assessment

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40th IEEE International Conference on Acoustics, Speech, and Signal Processing, ICASSP 2015

作者： Xu, Long Li, Jia Lin, Weisi Zhang, Yongbing Ma, Lin Fang, Yuming Zhang, Yun Yan, Yihua Key Laboratory of Solar Activity National Astronomical Observatories Chinese Academy of Sciences Beijing China State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering BeihangUniversity Beijing China International Research Institute for Multidisciplinary Science Beihang University Beijing China Department of Computer Engineering Nanyang Technological University Singapore Graduate School at Shenzhen Tsinghua University Shenzhen China Huawei Noah's Ark Lab Hong Kong School of Information Technology Jiangxi University of Finance and Economics Nanchang China Shenzhen Institutes of Advanced Technology Chinese Academy of Sciences Shenzhen China

ISBN: (纸本)9781467369978

In practice, multiple types of distortions are associated with an image quality degradation process. The existing machine learning (ML) based image quality assessment (IQA) approaches generally established a unified model for all distortion types, or each model is trained independently for each distortion type by using single-task learning, which lead to the poor generalization ability of the models as applied to practical image processing. There are often the underlying cross relatedness amongst these single-task learnings in IQA, which is ignored by the previous approaches. To solve this problem, we propose a multi-task learning framework to train IQA models simultaneously across individual tasks each of which concerns one distortion type. These relatedness can be therefore exploited to improve the generalization ability of IQA models from single-task learning. In addition, pairwise image quality rank instead of image quality rating is optimized in learning task. By mapping image quality rank to image quality rating, a novel no-reference (NR) IQA approach can be derived. The experimental results confirm that the proposed Multi-task Rank Learning based IQA (MRLIQ) approach is prominent among all state-of-the-art NR-IQA approaches. © 2015 IEEE.

关键词： image quality assessment machine learning MOS pairwise comparison Rank learning

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Vibration effects research on maintenance performance in virtual environment

Vibration effects research on maintenance performance in vir...

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作者： Guo, Zhiqi Lv, Chuan School of Reliability and System Engineering Beihang University Beijing China State Key Laboratory of Virtual Reality Technology and Systems Beijing China

In the past decades, virtual maintenance has been a vital tool to assist product maintainability design. However, these is few report about the vibration effects on maintenance which has been proved significantly to enhance worker fatigue. In this study, we develop a platform, Semi-physical Simulation Platform (SSP), to analyze vibration effects on maintenance where an advanced Rapid Upper Limb Assessment (A-RULA) is also proposed to realize both static and dynamic assessment of worker postures and fatigue. Furthermore, a series experiments with a specified maintenance task are taken into SSP to investigate the vibration effects on maintenance. The results demonstrate reasonable conclusions about the effects of various frequency vibration and fatigue on maintenance time, maintenance errors, and A-RULA obtained from SSP. © JVE INTERNATIONAL LTD.

关键词： virtual reality

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