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Data stream clustering algorithm based on spatial directed graph

Advances in Information Sciences and Service Sciences 2012年第20期4卷 241-249页

作者： Ren, Jiadong Yuan, Xuemei Dong, Jun College of Information Science and Engineering Yanshan University Qinhuangdao Hebei 066004 China The Key Laboratory for Computer Virtual Technology and System Integration of Hebei Province Qinhuangdao City 066004 China

Recently, the grid-density based clustering has become one of the major issues among all of the clustering approaches, it has special advantages over other clustering algorithms, such as less computation and the ability of clustering with arbitrarily shape, which are particularly useful for the data stream clustering. This paper defines a spatial directed graph named Grid-Based Graph (GBG) to store the non-empty grids in data space, and proposes a data stream clustering algorithm based on spatial directed graph GBGSClu (Grid-Based Graph Stream Clustering). GBG graph composes of vertices and directed edges, if a vertex A has a neighboring dense vertex B, and then there is a directed edge from vertex B to A in GBG. The algorithm maps the data stream into the non-empty vertices online, updates the vertices' feature vectors with the arriving of data stream, deletes the sparse vertices every gap time, generates GBG graph when the clustering quest coming and finally clusters on the current structure. The eventual clustering results can be obtained by only checking the vertices' in-degree which can reduce the computation needed in clustering. The validity and efficiency of GBGSClu algorithm have been tested and verified by clustering on real and synthetic datasets.

关键词： Directed graphs

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Commodity dynamic pricing and inventory joint decision-making model based on specific power demand function

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Revista Tecnica de la Facultad de Ingenieria Universidad del Zulia 2016年第4期39卷 74-81页

作者： Sun, Dejie Liu, Wenyuan Zhang, Jie School of Information Science and Engineering Yanshan University Qinhuangdao Hebei066004 China Key Laboratory for Computer Virtual Technology and System Integration of Hebei Province Qinhuangdao Hebei066004 China

Dynamic pricing and inventory play a respective role. The purpose of inventory is to try best to maintain an even production speed and efficiently ease supply-and-demand contradiction during the production process and among enterprises in the supply chain. However, dynamic pricing aims at maximizing revenues by setting commodities or services at different price levels according to diversified demands of consumers and different commodity or service price evaluation by consumers in different periods. Therefore, it is important for enterprises to optimize their dynamic pricing strategies and commodity inventory so as to maximize value of researches. However, demands for tangible commodities are uncertain. Generally speaking, the commodity demand volume should first be confirmed before any specific analysis. Therefore, this paper focuses on introducing the commodity demand function and relevant factors influencing the commodity demand volume. The utility function describing consumers' demands for a single commodity is analyzed. The specific power demand function model based on utility maximization is built through the utility function. At last, we conduct an in-depth analysis and simulation of the model.

关键词： Economics

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Exploring the Factors of Students' Online Learning Based on Structural Equation Modeling 11

Exploring the Factors of Students' Online Learning Based on ...

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11th IEEE International Conference on Teaching, Assessment and Learning for Engineering, TALE 2022

作者： Wan, Han Luo, Hongzhen Zhong, Zihao Yang, Jianlei Beihang University School of Computer Science and Engineering State Key Laboratory of Virtual Reality Technology and Systems Beijing China

ISBN: (纸本)9781665491174

Due to the COVID-19 pandemic, traditional teaching has been migrated online. Different from traditional face-to-face teaching, when students learn online, the online learning platform will generate various data. And these data make it possible for us to analyze students' final academic performance. In this paper, we use structural equation modeling (SEM) to analyze the relationship between students' learning factors. It is found that students' lab scores (LS), exercise scores (LS) and participation in the discussion (PID) have a direct impact on their final programming scores (FPS). This paper also finds that students' assignment submissions have an indirect influence on their final programming scores (FPS) but have a direct effect on lab scores (LS). In addition, students' participation in the discussion (PID) has an indirect influence on assignment submissions (AS) and lab scores (LS). The research in this paper can provide instructional designers with references for instructional design. © 2022 IEEE.

关键词： Students

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Effects of virtual environment and self-representations on perception and physical performance in redirected jumping

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virtual Reality & Intelligent Hardware 2021年第6期3卷 451-469页

作者： Yijun LI Miao WANG Derong JIN Frank STEINICKE Qinping ZHAO State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and EngineeringBeihang UniversityBeijing 100083China Peng Cheng Laboratory Shenzhen 518055China Universiẗat Hamburg Hamburg 21071Germany

Background Redirected jumping(RDJ)allows users to explore virtual environments(VEs)naturally by scaling a small real-world jump to a larger virtual jump with virtual camera motion manipulation,thereby addressing the problem of limited physical space in VR *** RDJ studies have mainly focused on detection threshold ***,the effect VE or self representation(SR)has on the perception or performance of RDJs remains *** In this paper,we report experiments to measure the perception(detection thresholds for gains,presence,embodiment,intrinsic motivation,and cybersickness)and physical performance(heart rate intensity,preparation time,and actual jumping distance)of redirected forward jumping under six different combinations of VE(low and high visual richness)and SRs(invisible,shoes,and human-like).Results Our results indicated that the detection threshold ranges for horizontal translation gains were significantly smaller in the VE with high rather than low visual *** different SRs were applied,our results did not suggest significant differences in detection thresholds,but it did report longer actual jumping distances in the invisible body case compared with the other two *** the high visual richness VE,the preparation time for jumping with a human-like avatar was significantly longer than that with other ***,some correlations were found between perception and physical performance *** All these findings suggest that both VE and SRs influence users'perception and performance in RDJ and must be considered when designing locomotion techniques.

关键词： virtual reality virtual locomotion Redirected jumping

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Single image based illumination estimation for lighting virtual object in real scene

Single image based illumination estimation for lighting virt...

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

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

ISBN: (纸本)9780769544977

Rendering virtual objects into real scenes with real illumination can greatly increase the realism of virtual objects and the consistency between the virtual and the real. The main challenge lies in illumination estimation from a single image. This article proposes a novel method of single image based illumination estimation for lighting virtual object in real scene. Only a single image, without any knowledge of the 3D geometry or reflectance, is needed, which greatly increases the applicability of the method. We first estimate coarse scene geometry and intrinsic components including shading image and reflectance image. Then the sparse radiance map of the scene is inferred based on the scene geometry and intrinsic components. Finally, the virtual objects are illuminated by the estimated sparse radiance map. Some experimental results show that this method can convincingly light virtual objects into a single real image, without any pre-recorded 3D geometry and reflectance, illumination acquisition equipments or imaging information of the image. © 2011 IEEE.

关键词： Geometry

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GPU accelerating for rapid multi-core cache simulation

GPU accelerating for rapid multi-core cache simulation

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25th IEEE International Parallel and Distributed Processing Symposium, Workshops and Phd Forum, IPDPSW 2011

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

ISBN: (纸本)9780769543857

To find the best memory system for emerging workloads, traces are obtained during application's execution, then caches with different configurations are simulated using these traces. Since program traces can be several gigabytes, simulation of cache performance is a time consuming process. Compute unified device architecture (CUDA) is a software development platform which enables programmers to accelerate the general-purpose applications on the graphics processing unit (GPU). This paper presents a real time multi-core cache simulator, which was built based on the Pin tool to get the memory reference;and fast method for multi-core cache simulation using the CUDA-enabled GPU. The proposed method is accelerated by the following techniques: execution parallelism exploration;memory latency hiding;a novel trace compression methodology. We describe how these techniques can be incorporated into CUDA code. Experimental results show that the hybrid parallel method of time-partitioning combines with set-partitioning presented here is 11.10× speedup compared to the CPU serial simulation algorithm. The present simulator can characterize cache performance of single-threaded or multi-threaded workloads at the speeds of 6-15 MIPS. It can simulates 6 cache configurations within one single pass at this speeds compared to CMP$im, which can only simulate one cache configuration each simulation pass at the speeds of 4-10 MIPS. © 2011 IEEE.

关键词： Graphics processing unit

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Face illumination transfer through edge-preserving filters

Face illumination transfer through edge-preserving filters

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

ISBN: (纸本)9781457703942

This article proposes a novel image-based method to transfer illumination from a reference face image to a target face image through edge-preserving filters. According to our method, only a single reference image, without any knowledge of the 3D geometry or material information of the target face, is needed. We first decompose the lightness layers of the reference and the target images into large-scale and detail layers through weighted least square (WLS) filter after face alignment. The large-scale layer of the reference image is filtered with the guidance of the target image. Adaptive parameter selection schemes for the edge-preserving filters is proposed in the above two filtering steps. The final relit result is obtained by replacing the large-scale layer of the target image with that of the reference image. We acquire convincing relit result on numerous target and reference face images with different lighting effects and genders. Comparisons with previous work show that our method is less affected by geometry differences and can preserve better the identification structure and skin color of the target face. © 2011 IEEE.

关键词： Bandpass filters

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Generative Cooperative Network for Person Image Generation 6

Generative Cooperative Network for Person Image Generation

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6th IEEE International Conference on Universal Village, UV 2022

作者： Liu, Yang Wang, Shuai Wu, Yubin Sheng, Hao Xiong, Zhang Beihang University State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beijing China

ISBN: (纸本)9781665474771

Person image generation is to synthesize realistic pedestrian images that follow the same distribution as the given dataset. Previous attempts can be generally categorized into two classes: some methods use human pose information as guidance and others try to generate person images from scratch. The former is to transfer the pose of a source image to a reference pose. The generated person image have the same identity as the source image. The latter takes a random noise from latent space as input, and the real person images are only used as references for the discriminator. While pose-guided person image generation is widely studied, generating-from-scratch methods are also worth exploring because they can synthesize person image with new identity, which is a useful manner of data augmentation. These two types of generating methods have their different advantages and disadvantages, and sometimes they are complementary. In this work, the authors design a Generative Cooperative Network (GCN) to jointly train two types of GANs. The two GANs serve different purposes, and can learn from each other during the cooperative learning procedure. The proposed approach is verified on public datasets, and the results show that our GCN improves the performance of the baseline methods. Comparisons with state-of-the-art methods also prove the effectiveness of the proposed method. © 2022 IEEE.

关键词： computer vision

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Efficient subtree results computation for XML keyword queries

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Frontiers of computer Science 2015年第2期9卷 253-264页

作者： Ziyang CHEN School of Information Science and Engineering Yanshan University Hebei 066004 China Environmental Management College of China Hebei 066004 China The Key Laboratory for Computer Virtual Technology and System Integration of HeBei Province Yanshan University Hebei 066004 China

In this paper, we focus on efficient construction of restricted subtree （RSubtree） results for XML keyword queries on a multicore system. We firstly show that the perfor- mance bottlenecks for existing methods lie in 1） computing the set of relevant keyword nodes （RKNs） for each subtree root node, 2） constructing the corresponding RSubtree, and 3） parallel execution. We then propose a two-step generic top-down subtree construction algorithm, which computes SLCA/ELCA nodes in the first step, and parallelly gets RKNs and generates RSubtree results in the second step, where generic means that 1） our method can be used to compute dif- ferent kinds of subtree results, 2） our method is independent of the query semantics; top-down means that our method con- structs each RSubtree by visiting nodes of the subtree con- structed based on an RKN set level-by-level from left to right, such that to avoid visiting as many useless nodes as possible. The experimental results show that our method is much more efficient than existing ones according to various metrics.

关键词： XML SLCA/ELCA RSubtree RKNs parallel

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Data-driven season characteristic enhancement of natural image

Data-driven season characteristic enhancement of natural ima...

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2013 7th International Conference on Image and Graphics, ICIG 2013

作者： Ding, Feng Li, Jianwei Zou, Dongqing Chen, Xiaowu State Key Laboratory of Virtual Reality Technology and Systems School of Computer Science and Engineering Beihang University Beijing China

ISBN: (纸本)9780769550503

We present a system of creating new scenes in different seasons from an input image captured in a particular season by stylizing it according to similar images in our library which includes a vast number of different season scenes and objects. Firstly, we transfer the color appearance of the input scene in accordance with the color style of other seasons scenes by using color transfer approach. Secondly, user scribbles are used to guide the detection of repeated elements in the input image and geometric information of these detected elements are obtained. Then context-sensitive objects of specified class that match most of the required properties are retrieved from our library and edited according to the geometric information of the specified elements in the scene, such as inserting new objects into the scene or replacing objects by new ones. After that, a repeated-elements-based modification duplication scheme is proposed and implemented to semi-automatically propagate the user-specified objects modification. Finally, blending is applied to the inserted objects to achieve consistency with the target scene in illumination. The main contribution of this work is that we present a complete system to create new scenes of different seasons. © 2013 IEEE.

关键词： Color

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