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International Conference on Cloud Computing

作者： Wu, Jing Zheng Ding, Liping Wang, Yongji Han, Wei National Engineering Research Center for Fundamental Software Institute of Software Beijing China State Key Laboratory of Computer Science Institute of Software Beijing China Graduate School Chinese Academy of Science Beijing China

ISBN: (纸本)9780769544601

Virtualization technology is the basis of cloud computing, and the most important property of virtualization is isolation. Isolation guarantees security between virtual machines. However, covert channel breaks the isolation and leaks sensitive message covertly. In this paper, we formally model the isolation into noninterference, and define that all the transmission channels violating noninterference are covert channels. With this definition, we present an identification method based on information flow. This method first compiles the source code into a more structured equivalent code with LLVM. And then a search algorithm is proposed to obtain the shared resources and the operational processes in the equivalent code. A new covert channel termed sharing memory covert timing channel (SMCTC) is identified from Xen source code. We construct channel scenario for SMCTC, and evaluate its threat with the metrics of channel capacity and transmission accuracy. The results show that SMCTC is much more threatened than CPU load based and cache based covert channels etc. © 2011 IEEE.

关键词： Virtual machine

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BibClus: A clustering algorithm of bibliographic networks by message passing on center linkage structure

BibClus: A clustering algorithm of bibliographic networks by...

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11th IEEE International Conference on Data Mining, ICDM 2011

作者： Xu, Xiaoran Deng, Zhi-Hong School of Electronics Engineering and Computer Science Peking University Beijing 100871 China State Key Lab of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China

ISBN: (纸本)9780769544083

Multi-type objects with multi-type relations are ubiquitous in real-world networks, e.g. bibliographic networks. Such networks are also called heterogeneous information networks. However, the research on clustering for heterogeneous information networks is little. A new algorithm, called NetClus, has been proposed in recent two years. Although NetClus is applied on a heterogeneous information network with a star network schema, considering the relations between center objects and all attribute objects linking to them, it ignores the relations between center objects such as citation relations, which also contain rich information. Hence, we think the star network schema cannot be used to characterize all possible relations without integrating the linkage structure among center objects, which we call the Center Linkage Structure, and there has been no practical way good enough to solve it. In this paper, we present a novel algorithm, BibClus, for clustering heterogeneous objects with center linkage structure by taking a bibliographic information network as an example. In BibClus, we build a probabilistic model of pairwise hidden Markov random field (P-HMRF) to characterize the center linkage structure, and convert it to a factor graph. We further combine EM algorithm with factor graph theory, and design an efficient way based on message passing algorithm to inference marginal probabilities and estimate parameters at each iteration of EM. We also study how factor functions affect clustering performance with different function forms and constraints. For evaluating our proposed method, we have conducted thorough experiments on a real dataset that we had crawled from ACM Digital Library. The experimental results show that BibClus is effective and has a much higher quantity than the recently proposed algorithm, NetClus, in both recall and precision. © 2011 IEEE.

关键词： Graph theory

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Demo: A sensor network time synchronization protocol based on fm radio data system 11

Demo: A sensor network time synchronization protocol based o...

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9th International Conference on Mobile Systems, Applications, and Services, MobiSys'11 and Co-located Workshops

作者： Li, Liqun Xing, Guoliang Sun, Limin Huangfu, Wei Zhou, Ruogu Zhu, Hongsong Institute of Software Chinese Academy of Sciences China Graduate University Chinese Academy of Sciences China Department of Computer Science and Engineering Michigan State University United States

No abstract available.

ISBN: (纸本)9781450306430

No abstract available.

关键词： wireless sensor network fm radio time synchronization radio data system

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Exploiting FM radio data system for adaptive clock calibration in sensor networks 11

Exploiting FM radio data system for adaptive clock calibrati...

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Proceedings of the 9th international conference on Mobile systems, applications, and services

ISBN: (纸本)9781450306430

Clock synchronization is critical for Wireless Sensor Networks (WSNs) due to the need of inter-node coordination and collaborative information processing. Although many message passing protocols can achieve satisfactory clock synchronization accuracy, they incur prohibitively high overhead when the network scales to more than tens of nodes. An alternative approach is to take advantage of the global time reference induced by existing infrastructures including GPS, timekeeping radio stations, or power grid. However, high power consumption and geographic constraints present them from being widely adopted in WSNs. In this paper, we propose ROCS, a new clock synchronization approach exploiting the Radio Data System (RDS) of FM radios. First, we design a new hardware FM receiver that can extract a periodic pulse from FM broadcasts, referred to as RDS clock. We then conduct a large-scale measurement study of RDS clock in our lab for a period of six days and on a vehicle driving through a metropolitan area of over 40 km2. Our results show that RDS clock is highly stable and hence is a viable means to calibrate the clocks of large-scale city-wide sensor networks. To reduce the high power consumption of FM receiver, ROCS intelligently predicts the time error due to drift, and adaptively calibrates the native clock via the RDS clock. We implement ROCS in TinyOS on our hardware FM receiver and a TelosB-compatible WSN platform. Our extensive experiments using a 12-node testbed and our driving measurement traces show that ROCS achieves accurate and precise clock synchronization with low power consumption. © 2011 ACM.

关键词： Synchronization

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Line drawing technique for building images

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Ruan Jian Xue Bao/Journal of software 2012年第SUPPL.2期23卷 34-41页

作者： Liu, You-Quan Wu, Zong-Sheng Wang, Shan-Dong Xue, Ru Wu, En-Hua School of Information Engineering Chang'an University Xi'an 710064 China Faculty of Science and Technology University of Macau Macao China State Key Laboratory of Computer Science Institute of Software The Chinese Academy of Sciences Beijing 100190 China Tibet University for Nationalities Xianyang 712082 China

This paper presents an automatic line-drawing method designed for building images. The fast line segment detector with a false detection control and detects the outline and the door, or window edge features detected, which are used in the construction of edge tangent flow. Based on the modified ETF, the Difference-of-Gaussians is used to render the final line drawing styles. This scheme gives clear line features for building images without much noise, which is also simple and easy to implement. The test results verify the effectiveness of the presented algorithm. © Copyright 2012, Editorial Department of Journal of software.

关键词： Rendering (computer graphics)

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The preservation of liveness in self-loops connection of Petri net systems

The preservation of liveness in self-loops connection of Pet...

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3rd International Conference on Multimedia Information Networking and Security, MINES 2011

作者： Fei, Pu College of Computer and Information Engineering Zhejiang Gongshang University China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences 100190 Beijing China

ISBN: (纸本)9780769545592

In study of Petri net systems, the approach of synthesis process is playing an increasingly significant role. In a synthesis process, the properties of subsystems must be preserved in the global system in order to reduce the high complexity of analyzing. This paper focuses on such property as live ness in self-loops connection of Petri net systems. The system behavior relation i.e. language relation in self-loops connection process is stressed studied. The corresponding concurrent language formula is presented and proved, and it can be applied to judge the live ness in self-loops connection operation. Moreover, some criteria are introduced, which are necessary and sufficient for live ness preservation. Then, under these conditions, the live ness of global system can be determined by the same properties of local systems. Contrasted with other works, our approaches can synthesize Petri net systems beyond asymmetric choice nets and are based on concurrent behavior of systems. © 2011 IEEE.

关键词： Petri nets

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Information security for service oriented computing: Ally or antagonist

Information security for service oriented computing: Ally or...

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2011 6th International Conference on Availability, Reliability and Security, ARES 2011

作者： Chetty, Jacqui Coetzee, Marijke Business Information Technology University of Johannesburg Johannesburg South Africa Academy of Computer Science and Software Engineering University of Johannesburg Johannesburg South Africa

ISBN: (纸本)9780769544854

Service-oriented Architecture (SOA) is a leading paradigm that can be used to address the challenges of both cross-organisational and inter-organisational systems integration. This approach makes it necessary to investigate and apply suitable SOA information security policies, controls and mechanisms in order to comprehensively address the information security of composed applications. While this is an active research field, literature on the topic has not yet identified a standard approach to SOA information security. This paper uses a security theory SOA-S, to identify and compare current best practices and challenges of SOA information security. Based on this comparison, research challenges for SOA information security are identified. © 2011 IEEE.

关键词： Security of data

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ListOPT: Learning to optimize for XML ranking

ListOPT: Learning to optimize for XML ranking

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作者： Gao, Ning Deng, Zhi-Hong Yu, Hang Jiang, Jia-Jian School of Electronic Engineering and Computer Science Peking University China State Key Lab. of Computer Science Institute of Software Chinese Academy of Sciences Beijing 100190 China

ISBN: (纸本)9783642208461

Many machine learning classification technologies such as boosting, support vector machine or neural networks have been applied to the ranking problem in information retrieval. However, since the purpose of these learning-to-rank methods is to directly acquire the sorted results based on the features of documents, they are unable to combine and utilize the existing ranking methods proven to be effective such as BM25 and PageRank. To solve this defect, we conducted a study on learning-to-optimize, which is to construct a learning model or method for optimizing the free parameters in ranking functions. This paper proposes a listwise learning-to-optimize process ListOPT and introduces three alternative differentiable query-level loss functions. The experimental results on the XML dataset of Wikipedia English show that these approaches can be successfully applied to tuning the parameters used in an existing highly cited ranking function BM25. Furthermore, we found that the formulas with optimized parameters indeed improve the effectiveness compared with the original ones. © 2011 Springer-Verlag.

关键词： Information retrieval

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High viscosity fluid simulation using particle-based method

High viscosity fluid simulation using particle-based method

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作者： Chang, Yuanzhang Bao, Kai Zhu, Jian Wu, Enhua Department of Computer and Information Science University of Macau Macao China State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing China Division of Mathematical and Computer Sciences and Engineering KAUST Thuwal Saudi Arabia

ISBN: (纸本)9781457700538

We present a new particle-based method for high viscosity fluid simulation. In the method, a new elastic stress term, which is derived from a modified form of the Hooke's law, is included in the traditional Navier-Stokes equation to simulate the movements of the high viscosity fluids. Benefiting from the Lagrangian nature of Smoothed Particle Hydrodynamics method, large flow deformation can be well handled easily and naturally. In addition, in order to eliminate the particle deficiency problem near the boundary, ghost particles are employed to enforce the solid boundary condition. Compared with Finite Element Methods with complicated and time-consuming remeshing operations, our method is much more straightforward to implement. Moreover, our method doesn't need to store and compare to an initial rest state. The experimental results show that the proposed method is effective and efficient to handle the movements of highly viscous flows, and a large variety of different kinds of fluid behaviors can be well simulated by adjusting just one parameter. © 2011 IEEE.

关键词： Navier Stokes equations

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RFID protocol based on random number and encryption hash

RFID protocol based on random number and encryption hash

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IET International Communication Conference on Wireless Mobile and Computing, CCWMC 2011

作者： Quan, Qian Xiang, Guo Rui, Zhang School of Computer Engineering and Science Shanghai University Shanghai 200072 China State Key Laboratory of Information Security Institute of Software Chinese Academy of Sciences China

ISBN: (纸本)9781849195058

The features of the RFID system and the constraints of RFID devices may bring about various privacy problems. After analyzing some existing RFID protocols, this paper proposes a new protocol based on random number and encryption hash. A process of formal analysis is presented by using BAN logic;the security and the complexity of this protocol are compared with other typical ones. The messages in the protocol are encrypted by key, it makes the protocol can prevent from illegal reading, tracking, eavesdropping, spoofing and replay attack. Both theory and analysis show that this new protocol can ensure the security of RFID systems and keep low-cost.

关键词： Radio frequency identification (RFID)

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