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Frontiers of Computer Science

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, Volume 12 Issue 4 Previous Issue   
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Cyber-physical-social collaborative sensing: from single space to cross-space
Fei YI, Zhiwen YU, Huihui CHEN, He DU, Bin GUO
Front. Comput. Sci.. 2018, 12 (4): 609-622.
Abstract   PDF (1144KB)

The development of wireless sensor networking, social networking, and wearable sensing techniques has advanced the boundaries of research on understanding social dynamics. Collaborative sensing, which utilizes diversity sensing and computing abilities across different entities, has become a popular sensing and computing paradigm. In this paper, we first review the history of research in collaborative sensing, which mainly refers to single space collaborative sensing that consists of physical, cyber, and social collaborative sensing. Afterward, we extend this concept into cross-space collaborative sensing and propose a general reference framework to demonstrate the distinct mechanism of cross-space collaborative sensing. We also review early works in cross-space collaborative sensing, and study the detail mechanism based on one typical research work. Finally, although cross-space collaborative sensing is a promising research area, it is still in its infancy. Thus, we identify some key research challenges with potential technical details at the end of this paper.

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Redesign of the gStore system
Front. Comput. Sci.. 2018, 12 (4): 623-641.
Abstract   PDF (601KB)

gStore is an open-source native Resource Description Framework (RDF) triple store that answers SPARQL queries by subgraph matching over RDF graphs. However, there are some deficiencies in the original system design, such as answering simple queries (including onetriple pattern queries). To improve the efficiency of the system, we reconsider the system design in this paper. Specifically, we propose a new query plan generation module that generates different query plans according to the structures of query graphs. Furthermore, we re-design our vertex encoding strategy to achieve more pruning power and a new multi-join algorithm to speed up the subgraph matching process. Extensive experiments on synthetic and real RDF datasets show that our method outperforms the state-of-the-art algorithms significantly.

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The role of model checking in software engineering
Anil Kumar KARNA, Yuting CHEN, Haibo YU, Hao ZHONG, Jianjun ZHAO
Front. Comput. Sci.. 2018, 12 (4): 642-668.
Abstract   PDF (1470KB)

Model checking is a formal verification technique. It takes an exhaustively strategy to check hardware circuits and network protocols against desired properties. Having been developed for more than three decades, model checking is now playing an important role in software engineering for verifying rather complicated software artifacts.

This paper surveys the role of model checking in software engineering. In particular, we searched for the related literatures published at reputed conferences, symposiums, workshops, and journals, and took a survey of (1) various model checking techniques that can be adapted to software development and their implementations, and (2) the use of model checking at different stages of a software development life cycle. We observed that model checking is useful for software debugging, constraint solving, and malware detection, and it can help verify different types of software systems, such as object- and aspect-oriented systems, service-oriented applications, web-based applications, and GUI applications including safety- and mission-critical systems.

The survey is expected to help human engineers understand the role of model checking in software engineering, and as well decide which model checking technique(s) and/or tool(s) are applicable for developing, analyzing and verifying a practical software system. For researchers, the survey also points out how model checking has been adapted to their research topics on software engineering and its challenges.

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StreamTune: dynamic resource scheduling approach for workload skew in video data center
Yihong GAO, Huadong MA
Front. Comput. Sci.. 2018, 12 (4): 669-681.
Abstract   PDF (786KB)

Video surveillance applications need video data center to provide elastic virtual machine (VM) provisioning. However, the workloads of the VMs are hardly to be predicted for online video surveillance service. The unknown arrival workloads easily lead to workload skew among VMs. In this paper, we study how to balance the workload skew on online video surveillance system. First, we design the system framework for online surveillance service which consists of video capturing and analysis tasks. Second, we propose Stream Tune, an online resource scheduling approach for workload balancing, to deal with irregular video analysis workload with the minimum number of VMs. We aim at timely balancing the workload skew on video analyzers without depending on any workload prediction method. Furthermore, we evaluate the performance of the proposed approach using a traffic surveillance application. The experimental results show that our approach is well adaptive to the variation of workload and achieves workload balance with less VMs.

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Fault-tolerant feedback virtual machine deployment based on user-personalized requirements
Shukun LIU, Weijia JIA, Xianmin PAN
Front. Comput. Sci.. 2018, 12 (4): 682-693.
Abstract   PDF (362KB)

A key requirement of the cloud platform is the reasonable deployment of its large-scale virtual machine infrastructure. The mapping relation between the virtual node and the physical node determines the specific resource distribution strategy and reliability of the virtual machine deployment. Resource distribution strategy has an important effect on performance, energy consumption, and guarantee of the quality of service of the computer, and serves an important role in the deployment of the virtual machine. To solve the problem of meeting the fault-tolerance requirement and guarantee high reliability of the application system based on the full use of the cloud resource under the prerequisite of various demands, the deployment framework of the feedback virtual machine in cloud platform facing the individual user’s demands of fault-tolerance level and the corresponding deployment algorithm of the virtual machine are proposed in this paper. Resource distribution strategy can deploy the virtual machine in the physical nodes where the resource is mutually complementary according to the users’ different requirements on virtual resources. The deployment framework of the virtual machine in this paper can provide a reliable computer configuration according to the specific fault-tolerance requirements of the user while considering the usage rate of the physical resources of the cloud platform. The experimental result shows that the method proposed in this paper can provide flexible and reliable select permission of faulttolerance level to the user in the virtual machine deployment process, provide a pertinent individual fault-tolerant deployment method of the virtual machine to the user, and guarantee to meet the user service in a large probability to some extent.

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Dropout training for SVMs with data augmentation
Ning CHEN, Jun ZHU, Jianfei CHEN, Ting CHEN
Front. Comput. Sci.. 2018, 12 (4): 694-713.
Abstract   PDF (2291KB)

Dropout and other feature noising schemes have shown promise in controlling over-fitting by artificially corrupting the training data. Though extensive studies have been performed for generalized linear models, little has been done for support vector machines (SVMs), one of the most successful approaches for supervised learning. This paper presents dropout training for both linear SVMs and the nonlinear extension with latent representation learning. For linear SVMs, to deal with the intractable expectation of the non-smooth hinge loss under corrupting distributions, we develop an iteratively re-weighted least square (IRLS) algorithm by exploring data augmentation techniques. Our algorithm iteratively minimizes the expectation of a reweighted least square problem, where the re-weights are analytically updated. For nonlinear latent SVMs, we consider learning one layer of latent representations in SVMs and extend the data augmentation technique in conjunction with first-order Taylor-expansion to deal with the intractable expected hinge loss and the nonlinearity of latent representations. Finally, we apply the similar data augmentation ideas to develop a new IRLS algorithm for the expected logistic loss under corrupting distributions, and we further develop a non-linear extension of logistic regression by incorporating one layer of latent representations. Our algorithms offer insights on the connection and difference between the hinge loss and logistic loss in dropout training. Empirical results on several real datasets demonstrate the effectiveness of dropout training on significantly boosting the classification accuracy of both linear and nonlinear SVMs.

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Learning from context: a mutual reinforcement model for Chinese microblog opinion retrieval
Jingjing WEI, Xiangwen LIAO, Houdong ZHENG, Guolong CHEN, Xueqi CHENG
Front. Comput. Sci.. 2018, 12 (4): 714-724.
Abstract   PDF (384KB)

This study addresses the problem of Chinese microblog opinion retrieval, which aims to retrieve opinionated Chinese microblog posts relevant to a target specified by a user query. Existing studies have shown that lexicon-based approaches employed online public sentiment resources to rank sentimentwords relying on the document features. However, this approach could not be effectively applied to microblogs that have typical user-generated content with valuable contextual information: “user–user” interpersonal interactions and “user–post/comment” intrapersonal interactions. This contextual information is very helpful in estimating the strength of sentiment words more accurately. In this study, we integrate the social contextual relationships among users, posts/comments, and sentiment words into a mutual reinforcement model and propose a unified three-layer heterogeneous graph, on which a random walk sentiment word weighting algorithm is presented to measure the strength of opinion of the sentiment words. Furthermore, the weights of sentiment words are incorporated into a lexicon-based model for Chinese microblog opinion retrieval. Comparative experiments are conducted on a Chinese microblog corpus, and the results show that our proposed mutual reinforcement model achieves significant improvement over previous methods.

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Instance selection method for improving graph-based semi-supervised learning
Hai WANG, Shao-Bo WANG, Yu-Feng LI
Front. Comput. Sci.. 2018, 12 (4): 725-735.
Abstract   PDF (346KB)

Graph-based semi-supervised learning is an important semi-supervised learning paradigm. Although graphbased semi-supervised learning methods have been shown to be helpful in various situations, they may adversely affect performance when using unlabeled data. In this paper, we propose a new graph-based semi-supervised learning method based on instance selection in order to reduce the chances of performance degeneration. Our basic idea is that given a set of unlabeled instances, it is not the best approach to exploit all the unlabeled instances; instead, we should exploit the unlabeled instances that are highly likely to help improve the performance, while not taking into account the ones with high risk. We develop both transductive and inductive variants of our method. Experiments on a broad range of data sets show that the chances of performance degeneration of our proposed method are much smaller than those of many state-of-the-art graph-based semi-supervised learning methods.

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Chromatic framework for quantum movies and applications in creating montages
Fei YAN, Sihao JIAO, Abdullah M. ILIYASU, Zhengang JIANG
Front. Comput. Sci.. 2018, 12 (4): 736-748.
Abstract   PDF (3595KB)

A framework that introduces chromatic considerations to earlier descriptions of movies on quantum computers is proposed. This chromatic framework for quantum movies (CFQM) integrates chromatic components of individual frames (each a multi-channel quantum image- MCQI state) that make up the movie, while each frame is tagged to a time component of a quantum register (i.e., a movie strip). The formulation of the CFQM framework and properties inherent to the MCQI images facilitate the execution of a cortege of carefully formulated transformations including the frame-to-frame (FTF), color of interest (COI), and subblock swapping (SBS) operations that are not realizable on other quantum movie formats. These innovative transformations are deployed in the creation of digital movie-like montages on the CFQM framework. Future studies could explore additional MCQI-related operations and their use to execute more advanced montage applications.

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Unification of identifiers in the Sea-Cloud system
Zheng HE, Kunpeng BAI, Dongdai LIN, Chuankun WU
Front. Comput. Sci.. 2018, 12 (4): 749-762.
Abstract   PDF (571KB)

The Sea-Cloud Innovative and Experimental Environment is designed for the Strategic Priority Research Program of the “Next Generation of Information Technology for Sensing China”. It was founded by the Chinese Academy of Sciences. There will be billions of heterogeneous devices in the “Sea” domain. Without unified identifier standards for these devices, issues such as confusion of identifier standards and duplicate identifiersmight arise when using these devices in the Sea-Cloud Environment. This paper proposes a unified identifier scheme for the Sea-Cloud system based on different existing identifier standards for different types of devices in the Sea domain. Furthermore, this paper defines a unique identifier for every person who uses smart devices in the Sea domain.

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Probabilistic verification of hierarchical leader election protocol in dynamic systems
Yu ZHOU, Nvqi ZHOU, Tingting HAN, Jiayi GU, Weigang WU
Front. Comput. Sci.. 2018, 12 (4): 763-776.
Abstract   PDF (693KB)

Leader election protocols are fundamental for coordination problems—such as consensus—in distributed computing. Recently, hierarchical leader election protocols have been proposed for dynamic systems where processes can dynamically join and leave, and no process has global information. However, quantitative analysis of such protocols is generally lacking. In this paper, we present a probabilistic model checking based approach to verify quantitative properties of these protocols. Particularly, we employ the compositional technique in the style of assume-guarantee reasoning such that the sub-protocols for each of the two layers are verified separately and the correctness of the whole protocol is guaranteed by the assume-guarantee rules. Moreover, within this framework we also augment the proposed model with additional features such as rewards. This allows the analysis of time or energy consumption of the protocol. Experiments have been conducted to demonstrate the effectiveness of our approach.

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Stable and realistic crack pattern generation using a cracking node method
Juan ZHANG, Fuqing DUAN, Mingquan ZHOU, Dongcan JIANG, Xuesong WANG, Zhongke WU, Youliang HUANG, Guoguang DU, Shaolong LIU, Pengbo ZHOU, Xiangang SHANG
Front. Comput. Sci.. 2018, 12 (4): 777-797.
Abstract   PDF (3422KB)

This paper presents a method for simulating surface crack patterns appearing in ceramic glaze, glass, wood and mud. It uses a physically and heuristically combined method to model this type of crack pattern. A stress field is defined heuristically over the triangle mesh of an object. Then, a first-order quasi-static cracking node method (CNM) is used to model deformation. A novel combined stress and energy combined crack criterion is employed to address crack initiation and propagation separately according to physics. Meanwhile, a highest-stress-first rule is applied in crack initiation, and a breadth-first rule is applied in crack propagation. Finally, a local stress relaxation step is employed to evolve the stress field and avoid shattering artifacts. Other related issues are also discussed, such as the elimination of quadrature sub-cells, the prevention of parallel cracks and spurious crack procession. Using this method, a variety of crack patterns observed in the real world can be reproduced by changing a set of parameters. Consequently, our method is robust because the computational mesh is independent of dynamic cracks and has no sliver elements. We evaluate the realism of our results by comparing them with photographs of realworld examples. Further, we demonstrate the controllability of our method by varying different parameters.

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A perceptual quality metric for 3D triangle meshes based on spatial pooling
Xiang FENG, Wanggen WAN, Richard Yi Da XU, Haoyu CHEN, Pengfei LI, J. Alfredo SÁNCHEZ
Front. Comput. Sci.. 2018, 12 (4): 798-812.
Abstract   PDF (866KB)

In computer graphics, various processing operations are applied to 3D triangle meshes and these processes of ten involve distortions, which affect the visual quality of surface geometry. In this context, perceptual quality assessment of 3D triangle meshes has become a crucial issue. In this paper, we propose a new objective quality metric for assessing the visual difference between a reference mesh and a corresponding distorted mesh. Our analysis indicates that the overall quality of a distorted mesh is sensitive to the distortion distribution. The proposed metric is based on a spatial pooling strategy and statistical descriptors of the distortion distribution. We generate a perceptual distortion map for vertices in the reference mesh while taking into account the visual masking effect of the human visual system. The proposed metric extracts statistical descriptors from the distortion map as the feature vector to represent the overall mesh quality. With the feature vector as input, we adopt a support vector regression model to predict the mesh quality score.We validate the performance of our method with three publicly available databases, and the comparison with state-of-the-art metrics demonstrates the superiority of our method. Experimental results show that our proposed method achieves a high correlation between objective assessment and subjective scores.

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Identification and prioritization of differentially expressed genes for time-series gene expression data
Linlin XING, Maozu GUO, Xiaoyan LIU, Chunyu WANG
Front. Comput. Sci.. 2018, 12 (4): 813-823.
Abstract   PDF (1073KB)

Identification of differentially expressed genes (DEGs) in time course studies is very useful for understanding gene function, and can help determine key genes during specific stages of plant development. A few existing methods focus on the detection of DEGs within a single biological group, enabling to study temporal changes in gene expression. To utilize a rapidly increasing amount of single-group time-series expression data, we propose a two-step method that integrates the temporal characteristics of time-series data to obtain a B-spline curve fit. Firstly, a flat gene filter based on the Ljung–Box test is used to filter out flat genes. Then, a B-spline model is used to identify DEGs. For use in biological experiments, these DEGs should be screened, to determine their biological importance. To identify high-confidence promising DEGs for specific biological processes, we propose a novel gene prioritization approach based on the partner evaluation principle. This novel gene prioritization approach utilizes existing co-expression information to rank DEGs that are likely to be involved in a specific biological process/condition. The proposed method is validated on the Arabidopsis thaliana seed germination dataset and on the rice anther development expression dataset.

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14 articles