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A real-time simulation method for large-scale 3D clouds

Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao/Journal of computer-Aided Design and computer Graphics 2010年第4期22卷 662-669页

作者： Ren, Wei Liang, Xiaohui Ma, Shang Shen, Xukun State Key Laboratory of Virtual Reality Technology and Systems Beijing 100191 China School of Computer Science and Engineering Beihang University Beijing 100191 China

According to the problem of time consuming on large-scale 3D clouds rendering in virtual environment, this paper presents a real-time simulation method for large-scale 3D clouds. In modeling process, the Navier-Stokes equations are adopted for cloud modeling, and a method based on octree is presented to reduce the particle number of the cloud model. In rendering process, impostor technique is used and a schedule algorithm based on Cell is proposed to render the mixed 3D clouds and impostor automatically. As the clouds are simulated by physical model and updated in real time when the view moves, the rendering effect is highly realistic. Compared with other works, our algorithm based on Cell schedule shows better efficiency on computation, and substantially improves the jerky phenomenon effectively.

关键词： virtual reality

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Motion Choreographing Based on Kinetic Energy with Accelerometer Signal

Motion Choreographing Based on Kinetic Energy with Accelerom...

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International Conference on Multimedia technology

作者： Yubo Liu Xiaohui Liang Zhiying He State Key Laboratory of Virtual Reality Technology School of Computer Science Beihang University Beijing China

ISBN: (纸本)9781424478712

Motion choreographing is extremely important nowadays. To provide an intuitive control interface and improve the end-user's experience, low-cost accelerometer, which serving as creating and choreographing character animation based on the performers' movements, attracts more and more researchers. This paper proposes a new feature vector using kinetic energy, which can be calculated from acceleration directly. Our method gives the feature vector more accurate physical significance and improves the recognition rate. Furthermore, post-processing for signal refinement can also benefit from it. We build a prototype of motion recognition system to verify our method. Experiments show that the proposed method leads to a higher recognition rate comparing to typical methods on a database of 48 pre-trained signal data with 8 different categories.

关键词： Kinetic energy Hidden Markov models Accelerometers Acceleration Timing Animation Prototypes

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A Dynamic Multi-radio Multi-channel MAC Protocol for Wireless Sensor Networks

A Dynamic Multi-radio Multi-channel MAC Protocol for Wireles...

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International Conference on Communication Software and Networks, ICCSN

作者： Zhiwu Liu Wei Wu State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science BeiHang University Beijing China

For improving throughput and energy efficiency in wireless sensor networks, multi-channel media access control has been proposed. Existing multi-channel MAC protocols are mainly focus on channel assignment and media access, it means that a senor node is bound with one channel, which makes the whole network inflexible and cannot be adapted to the variations of environment. In this paper, we proposed a Dynamic Multi-radio Multi-channel media Access control (DMMA) for wireless sensor networks, it can chose the channel dynamically according to the changing of spectrum environment, and make the network more robust to the interferences from external surroundings, meanwhile, take into account the energy efficiency, DMMA use a sleeping-based mechanism to reduce energy consumption. We also invent an ARM9 based four radios wireless sensor node to evaluate our solution on a real sensor network. Through our experiments, DMMA can avoid the impact of interference effectively, and also it achieves good fairness for multiple channel access.

关键词： Media Access Protocol Wireless application protocol Wireless sensor networks Interference Access protocols Energy efficiency Throughput Frequency virtual reality computer science

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International Conference on Educational and Information technology (ICEIT)

作者： Senshen Hao Jian Jiao Chunhe Xia Xiaojian Li Shan Yao State Key Laboratory of Virtual Reality Technology and System Beijing Key Laboratory of Network Technology School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9781424480333

In order to effectively deal with large-scale attacks on computer networks, computer Network Defense (CND) policy refinement based on descriptive language is wildly used. However, it's very difficult to figure out the semantic discrepancies between the measures and the predefined policy after the calculation with symbols by computers. A new method is presented to solve the discordance of semantic between the measures and the predefined policy automatically. Based on the establishment of the ontology of CND policy and measure (CNDPM), the CND policy and measure semantic similarity analysis model (CNDPMSSAM) is established, and then the termination of the two main components of CNDPMSSAM are proofed by the putdown automaton, and the prototype system of CNDPMSSAM is implemented. At last, we validate the validity of this method on analyzing semantic similarity of transferring from computer Network Defense Policy Specification Language (CNDPSL) to Defense Measure Description Language (DMDL) with experiments.

关键词： CND measure CND policy ontology semantic similarity Ontology Semantics Policies ANALYSIS MODELS Discordance Signs and symbols

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Simplification for texture mapping models with mesh segmentation

Simplification for texture mapping models with mesh segmenta...

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International Conference on virtual Systems and MultiMedia

作者： Lili Wang Zhiqiang Ma Bing Xue Zhe Shen State Key Laboratory of Virtual Reality Technology and System School of Computer Science and Engineering Beihang University Beijing China

To reduce the loss of visual details in simplification for textured meshes, this paper presents a simplification method based on mesh segmentation. Firstly, the model is partitioned into some sub-meshes according to their properties of appearance, such as texture, normal, etc. Thus, the correlation between sub-meshes can be decreased. Then, we calculate the error metric for the edge collapse in each sub-mesh. Lastly, we merge the simplified sub-meshes and fix the gap among them to regain an integrated mesh. Because the properties of appearance are used to separate the high-frequency details from low-frequency ones, our approach decreases the loss of the detailed. Therefore, we can not only keep the over whole contours of the model, but also maintain better geometric and appearance details. The results of experiments demonstrate our mesh segmentation based method is effective.

关键词： Mathematical model Measurement Equations Solid modeling Image edge detection Visualization Adaptation model

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Interval-valued Matrix Factorization with Applications

Interval-valued Matrix Factorization with Applications

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IEEE International Conference on Data Mining (ICDM)

作者： Zhiyong Shen Liang Du Xukun Shen Yidong Shen Hewlett Packard Laboratories China State Key Laboratory of Virtual Reality Technology and Systems China State Key Laboratory of Computer Science China

In this paper, we propose the Interval-valued Matrix Factorization (IMF) framework. Matrix Factorization (MF) is a fundamental building block of data mining. MF techniques, such as Nonnegative Matrix Factorization (NMF) and Probabilistic Matrix Factorization (PMF), are widely used in applications of data mining. For example, NMF has shown its advantage in Face Analysis (FA) while PMF has been successfully applied to Collaborative Filtering (CF). In this paper, we analyze the data approximation in FA as well as CF applications and construct interval-valued matrices to capture these approximation phenomenons. We adapt basic NMF and PMF models to the interval-valued matrices and propose Interval-valued NMF (I-NMF) as well as Interval-valued PMF (I-PMF). We conduct extensive experiments to show that proposed I-NMF and I-PMF significantly outperform their single-valued counterparts in FA and CF applications.

关键词： Face Matrix decomposition Linear approximation Sparse matrices Face recognition Pixel

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Descriptive model of peer-to-peer Botnet structures

Descriptive model of peer-to-peer Botnet structures

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International Conference on Educational and Information technology (ICEIT)

作者： Junfeng Duan Jian Jiao Chunhe Xia Shan Yao Xiaojian Li State Key Laboratory of Virtual Reality Technology and System Beijing Key Laboratory of Network Technology School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9781424480333

Peer-to-peer (P2P) Botnets, which are more resilient and robust than centralized botnets, have emerged as the peer-to-peer technology evolves. Better understanding of this new phenomenon will help researchers develop detection and mitigation methods. Most of existing work is case study of typical P2P botnets. In this paper, we focus on systematically analyzing structures of P2P botnets. We propose a descriptive model of P2P botnet structures, which consists of features of P2P bot, definitions of structures, and structural properties. Firstly, we detail two key functionalities of P2P bot, command-and-control (C&C) functionality and peer-to-peer (P2P) functionality, and give several features of P2P bot. And then, we define two structures of P2P botnets: C&C structure and P2P structure. To characterize these structures, we propose several properties and corresponding quantitative methods. Finally, we conduct experiments to verify our results.

关键词： Peer to peer computing Routing protocols Concrete Storms Analytical models Fires

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Image retargeting based on delaunay triangle mesh

Image retargeting based on delaunay triangle mesh

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International Conference on Advanced Information Management and Service

作者： Zhigao Chen Wei Li Xiaoyan Li Tianran Li Naveed Akram State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China

Accurate presentation of high resolution images on wide varieties of multimedia devices, especially on pervasive mobile multimedia devices, faces great challenge. In this paper, we present an angle preserved warping method for image retargeting which allows resizing images to arbitrary aspect ratios while minimizing the loss of important information. To accomplish this, we first cover the original image with a Delaunay triangle mesh based on saliency map of the image, which is computed by considering the lumination, color, gradient and position features of the pixels comprehensively; and then the triangle mesh is deformed to target aspect ratios subject to a deformation loss function, to drive the visual prominent features to undergo similarity transformations. The deformation loss function is constrained by the angle's changes of the triangles in the triangle mesh. Compared with previous approaches using grid mesh, our method can transfer the distortion caused by the change of the image aspect ratios to less saliency regions much more effectively.

关键词： Pixel Image color analysis Equations Image edge detection Shape Mathematical model Multimedia communication

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ACCELERATE SMOOTHED PARTICLE HYDRODYNAMICS USING GPU

ACCELERATE SMOOTHED PARTICLE HYDRODYNAMICS USING GPU

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2010 IEEE Youth Conference on Information,Computing and Telecommunications(2010 IEEE青年信息、计算和通信技术大会)

作者： Xiaopeng Gao Zhiqiang Wang Han Wan Xiang Long State Key Laboratory of Virtual Reality Technology and System School of Computer Science and Engineering Beihang University 100191 Beijing China

Physic-based fluid simulation is used extensively nowadays;however the traditional serial algorithm can’t satisfy the realtime requirement due to its complexity and computeintensive. The development of modern GPU makes this possible. In this paper, a Smoothed Particle Hydrodynamics (SPH) method for incompressible fluid was implemented using CUDA on GPU. Since the algorithm was executed on the GPU entirely, the method can take full advantage of massive computational power of modern graphics hardware. The experiment results show that our GPU based SPH implementation can achieve the rate of 89 frames per second in the simulation of 102K particles and gain nearly 140x speedups compared with the serial algorithm.

关键词： CUDA fluid simulation Smoothed Particle Hydrodynamics GPU acceleration

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GPU-BASED TIME PARALLEL CACHE SIMULATOR

GPU-BASED TIME PARALLEL CACHE SIMULATOR

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2010 IEEE Youth Conference on Information,Computing and Telecommunications(2010 IEEE青年信息、计算和通信技术大会)

作者： Junjie Ma Han Wan Xiaopeng Gao Xiang Long State Key Laboratory of Virtual Reality Technology and System School of Computer Science and Engineering Beihang University Xueyuan Rd.37 100191 Beijing China

We present the design of time parallel trace-driven cache simulation for the purpose of evaluating different cache architectures. Due to the long simulation cycles, traditional sequential simulation methods are no longer practical. An obvious way to achieve fast parallel simulation is time parallel. It splits the whole trace into small slices which are assigned to parallel processors for concurrent simulation. In this paper, we introduce a novel time parallel multiconfiguration simulation on single pass method. It exploits time partitioning as the main sources of parallelism and takes the full advantage of the computational capability offered by the Compute Unified Device Architecture (CUDA) on the GPU. Our experimental results demonstrate that the cache simulator based on GPU platform gains 1.91x performance improvement compared to traditional serial algorithm.

关键词： cache simulation trace-driven simulation time partitioning GPU CUDA

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