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2011 International Conference on Computational and Information Sciences, ICCIS 2011

作者： Fan, Beibei Liang, Xiaoyan Luo, Yang Bo, Yang Xia, Chunhe State Key Laboratory of Virtual Reality Technology and System School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9780769545011

Cross-domain interoperation based on role-mapping increasingly becomes a representative research field of collaborative environment. However, in this collaborative environment, there would still be more permission or less than the role of role-mapping policy required when authorization, this situation can not be completely avoided. This disaccord will result in conflict of access control policies (ACPs) in collaborative domains, and ultimately lead to unauthorized access to resources in autonomy domains. A new method is presented to detect the conflict between access control policies in collaborative environment automatically. The ACPs conflict detection model (ACPCDM) is established, the termination of ACPCDM is proved by the putdown automation, and the prototype system is implemented. At last, we validate the validity of this method with experiments, the result of the experiments shows that the analysis report of conflict can not only detect if there is conflict, but also figure out the conflict type, the causes and location of the conflict. So it is much easier for administer in each domain to resolve the conflict. © 2011 IEEE.

关键词： Mapping

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Image based experiment scene builder for virtual educational experiments

Image based experiment scene builder for virtual educational...

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2011 International Conference on virtual Reality and Visualization, ICVRV 2011

作者： Chi, Changjian Chen, Xiaowu Yang, Ziqiang Jia, Guodong State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9780769546025

Realism and simplicity of virtual experiment scene building can influence the usage of virtual educational experiment applications. This paper proposes an image based method of experiment scene building for virtual Educational Experiments. Firstly, virtual educational experiment components are extracted from images of experiment instrument by using the interactive method of object extraction. Then, the corresponding logical model descriptions are attached to the extracted components. Finally, the components required in a specific experiment are inserted into the selected virtual experiment scene and are connected interactively. A routing algorithm based on equivalent connection line is designed to make the generated line connections between components clear and legible. A virtual experiment scene building system, named VE Scene builder, has been implemented and widely used. The feedbacks demonstrated that our system can rapidly generate realistic and legible virtual experiment scene. © 2011 IEEE.

关键词： Routing algorithms

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Automatic compositing soccer video highlights with core-around event model

Automatic compositing soccer video highlights with core-arou...

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12th International Conference on computer-Aided Design and computer Graphics, CAD/Graphics 2011

作者： Jiang, Kai Chen, Xiaowu Zhao, Qinping State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9780769544977

This paper presents an automatic video highlighting approach in relation to a soccer match video lasting over ninety minutes, in which only the match video and the target length of the highlight video are required for the composition. Firstly, we propose a core-around event model, which represents the highlight as a complex event and consists of three components: semantic relations, temporal relationship among the activities and local motion appearance of each activity. Secondly, we detect activities involved in a highlight in the soccer match video by the local motion appearance. Thirdly, a candidate highlight video segment is aligned with the model by a specific kernel activity extracted on the basis of the semantic relations, and then assigned a matching score. Finally, we splice together the highlight segments of high matching score. Experimental results demonstrate that the composed highlight videos are attractive episodes of soccer matches, and similar to those edited by professional editors. © 2011 IEEE.

关键词： Semantics

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A Network Security Situation Analysis framework based on information fusion

A Network Security Situation Analysis framework based on inf...

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2011 6th IEEE Joint International Information technology and Artificial Intelligence Conference, ITAIC 2011

作者： Zhang, Songmei Yao, Shan Ye, Xin'En Xia, Chunhe State Key Laboratory of Virtual Reality Technology and System School of Computer Science and Engineering Beihang University Beijing 100191 China

ISBN: (纸本)9781424486236

With the rapid development of the Internet, the network structure becomes larger and more complicated and attacking methods are more sophisticated, too. To enhance network security, Network Security Situation Analysis (NSSA) technology is a research hot spot in the network security domain. But at present, the NSSA framework and model which not only analyze the affected results of the network security but also the process how the network security is affected are less. In this paper, a novel NSSA framework is presented. The framework includes two parts: calculate the Network Security Situation Value (NSSV) and discover intrusion processes. NSSA quantitative assesses the impact on network security caused by attacks upon Analytical Hierarchy Process (AHP) and hierarchical network structure. Based on attack classification, intrusion processes discover the process how network security is affected. At last from the experiments results, NSSV exactly changes as attacks take place and the accurate intrusion processes are discovered. The applicability of the framework and algorithms are verified. © 2011 IEEE.

关键词： Network security

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3D model multiple semantic automatic annotation for small scale labeled data set

3D model multiple semantic automatic annotation for small sc...

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2011 International Conference on virtual Reality and Visualization, ICVRV 2011

作者： Tian, Feng Shen, Xu-Kun Xian-Mei, Liu Hong-Tao, Xie State Key Laboratory of Virtual Reality Technology and Systems BeiHang University Beijing China School of Computer and Information Technology Northeast Petroleum University DaQing China

ISBN: (纸本)9780769546025

Automatically assigning keywords to 3D models is of great interest as it allows one to retrieve, index, organize and understand large collections of 3D models. Most Methods require high sample size for training, so the data quality is in high demand. For small scale labeled data set, we propose a semi-supervised method to realize the 3D models multiple semantic annotation, which needs only a small amount of hand tagged information provided by users. The proposed technique utilizes low-level shape features and the keywords are assigned using a graphed-based label transfer mechanism to expand the training dataset. A weighted metric learning method is used to learn the distance measure from the extended dataset. Then multiple semantic annotation task can be completed on the learned distance measure. The proposed method outperforms the current state-of-the-art methods on the small scale labeled dataset and large unlabelled dataset. We believe that such measure will provide a strong platform to label 3D models when a small amount of labeled models were given. © 2011 IEEE.

关键词： Semantics

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Timeline generation through evolutionary trans-temporal summarization

Timeline generation through evolutionary trans-temporal summ...

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Conference on Empirical Methods in Natural Language Processing, EMNLP 2011

作者： Yan, Rui Kong, Liang Huang, Congrui Wan, Xiaojun Li, Xiaoming Zhang, Yan School of Electronics Engineering and Computer Science Peking University China Institute of Computer Science and Technology Peking University China State Key Laboratory of Virtual Reality Technology and Systems Beihang University China

ISBN: (纸本)1937284115

We investigate an important and challenging problem in summary generation, i.e., Evolutionary Trans-Temporal Summarization (ETTS), which generates news timelines from massive data on the Internet. ETTS greatly facilitates fast news browsing and knowledge comprehension, and hence is a necessity. Given the collection of time-stamped web documents related to the evolving news, ETTS aims to return news evolution along the timeline, consisting of individual but correlated summaries on each date. Existing summarization algorithms fail to utilize trans-temporal characteristics among these component summaries. We propose to model trans-temporal correlations among component summaries for timelines, using inter-date and intra-date sentence dependencies, and present a novel combination. We develop experimental systems to compare 5 rival algorithms on 6 instinctively different datasets which amount to 10251 documents. Evaluation results in ROUGE metrics indicate the effectiveness of the proposed approach based on trans-temporal information. © 2011 Association for Computational Linguistics.

关键词： Computational linguistics

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A Publish/Subscribe based correlative matching method for multi-domain virtual environment

A Publish/Subscribe based correlative matching method for mu...

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IEEE International Symposium on VR Innovation

作者： Liu, Li Wu, Wei Chen, Hongqian School of Computer Science and Information Engineering Beijing Technology and Business University Beijing 100048 China State Key Laboratory of Virtual Reality Technology Beihang University Beijing 100083 China

ISBN: (纸本)9781457700538

The multi-domain virtual environment is an important research area of the distributed virtual reality. However, frequent interaction, great quantity of messages and the discrepant need of each individual simulation domain resulted in numerous redundant messages. In this paper, we propose a Publish/Subscribe based correlative matching method for multi-domain virtual environment. This method focus on data filtering of domains' gateways in addition to the DDM scheme. The paper introduces the correlative matching algorithm, the binary representation and the matching method which based on publish/subscribe relationship. Analysis and experiments show that this new solution effectively reduces the redundant data transferring among gateways, thus greatly enhances the performance of the virtual environment, and that the cost of matching method is relative small in multi-domain virtual environment application. © 2011 IEEE.

关键词： virtual reality

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Cooperatively resolving occlusion between real and virtual in multiple video sequences

Proceedings - 2011 6th Annual ChinaGrid Conference, ChinaGri...

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Proceedings - 2011 6th Annual ChinaGrid Conference, ChinaGrid 2011 2011年 234-240页

作者： Jin, Xin Chen, Xiaowu Zhou, Bin Lin, Hongchang State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9780769544724

The occlusion between real and virtual objects influences not only seamless merging of virtual and real environments but also users' visual perception of orientations & locations and spatial interactions in augmented reality. If there exist a large amount of video sequences for representing the real environment, and each video sequence utilizes computer vision algorithms to deal with all of occlusions between real and virtual, this often drops down the real-time performance of augmented reality system. This article proposed an approach of cooperatively resolving the occlusion between real and virtual based on multiple video sequences in augmented reality scene. Firstly it analyzes the occlusion relations between virtual and real objects in initial video sequences with their intrinsic parameters and poses, and obtains the spatial relations among video sequences through 3D registration information. Secondly, for each video sequence, it divides and codes the perception regions of relative augmented reality scene. Lastly, according to the spatial relations of video sequences, the known occlusion relations in initial video sequences and the code data of perception regions, three types of occlusion relations including real occluding virtual, virtual occluding real and non-occlusion are detected out and represented in augmented reality scene. Some experimental results show that this approach can reduce redundant calculations on the way of resolving the occlusion between real and virtual objects, and improve the performance of generating augmented reality scene, especially which includes plenty of video sequences and occlusion relations of virtual occluding real or non-occlusion. © 2011 IEEE.

关键词： Augmented reality

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Modeling and Visualizing Dynamic Component for virtual Educational Experiments

Modeling and Visualizing Dynamic Component for Virtual Educa...

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第十一届中国虚拟现实大会(ICVRV2011)

作者： Ziqiang Yang Xiaowu Chen Guodong Jia State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Technology Beihang University Beijing China

virtual experiments have been used in education for a long time. However, most of the virtual experiments are modeled only for some special subjects, and are programmed case by case. To handle these problems, an online system of virtual Educational Experiments (VEEs) is designed to develop various virtual experiments and simplify the virtual experiment modeling by reusing the existed experiment components. Based on the system of VEEs, we proposed a method of modeling and visualizing dynamic experiment components. Firstly, the dynamic experiment components are modeled based on the combination of images and graphics. Then the visualization of the dynamic experiment components is designed for multidisciplinary virtual experiments. The system has been running in some colleges and universities for several months. The tests show that it can rapidly model dynamic experiment components and realistically visualize the dynamic experiment components for the system of VEEs.

关键词： virtual Educational Experiments Dynamic experiment component Modeling Visualization

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Collaborative Augmented Reality Ping-pong via Markerless Real Rackets

Collaborative Augmented Reality Ping-pong via Markerless Rea...

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第十一届中国虚拟现实大会(ICVRV2011)

作者： Yong Yan Xiaowu Chen Xin Li State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Technology Beihang University Beijing China

This article proposes a method of constructing a ping-pong system via markerless real rackets in collaborative augmented reality. Except a pair of video cameras, without any other sensors or artificial markers, users can use real rackets to hit virtual ping-pong ball on a virtual table and interact with remote partners in augmented reality scene just as they were playing ping-pong in the same place. First, the real racket can be detected and tracked in real-time in the video captured by a single camera in each site. By 3D registration, the real racket can seamlessly interact with the virtual ping-pong ball and table. Then, a communication scheme is designed for the consistent perception between users in collaborative augmented reality ping-pong system. To achieve real-time interaction, the whole method is implemented in a parallel computing environment through multi-core processors. Experimental results demonstrate that our system can provide consistent perception and natural user interaction with low latency and high precision.

关键词： collaborative augmented reality ping-pong real racket real-time

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