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Detecting null dereference with a game

2012 International Conference on Information technology and Software Engineering, ITSE 2012

作者： Chen, Jie National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology 410073 Changsha China

ISBN: (纸本)9783642345302

As one of the most dangerous and common software vulnerabilities, null dereference often leads to program crashes. In this chapter we propose a human computation method to detect null dereference in a "frog and bug" game. The purpose of the game is to utilize the rich distributed human resource to do the complex science work in a simple and pleasant way. Programs are transformed into visual puzzles first, and then the server collects information from the people playing the game. Finally the recorded metadata is translated back into the positions in the programs where null dereference may happen. The game has shown to be effective. © 2013 Springer-Verlag.

关键词： Computers

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Fault tolerant Lu factorization in transactional memory system

Fault tolerant Lu factorization in transactional memory syst...

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2013 IEEE Conference Anthology, ANTHOLOGY 2013

作者： Song, Wei Jia, Jia National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China

ISBN: (纸本)9781479916603

With the popularization of multi-core processors, transaction memory, as a concurrent control mechanism with easy programing and high scalability, has attracted more and more attention. As a result, the reliability problems of transactional memory become a concerning issue. This paper addresses a transactional implementation of the Lu benchmark of SPLASH-2, and proposes a fault-tolerant Lu algorithm for this transactionalize Lu algorithm. The fault-tolerant Lu uses the data-versioning mechanism of the transactional memory system, detects errors based on transactions and recovers the error by rolling back the error transaction. The experiments show that the fault-tolerant Lu can get a better fault tolerance effect under a smaller cost. © 2013 IEEE.

关键词： Errors

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Continuous probabilistic reverse skyline monitoring over uncertain data streams

Continuous probabilistic reverse skyline monitoring over unc...

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2013 International Conference on Vehicle and Mechanical Engineering and Information technology, VMEIT 2013

作者： Yang, Yong Tao Wang, Yi Jie Guo, Min Li, Xiao Yong National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9783037858202

Reverse skyline is useful for supporting many applications, such as marketing decision, environmental monitoring. Since the uncertainty of data is inherent in many scenarios, there is a need for processing probabilistic reverse skyline queries. In this paper, we study the problem of efficiently processing these queries on uncertain data streams. We first show the formal definitions of reverse skyline probability and probabilistic reverse skyline. Then we propose a new algorithm called CPRS to maintain the most recent N uncertain data elements and to process continuous queries on them. CPRS is based on R-tree, and efficient pruning techniques, one of which is based on a new structure named Characteristic Rectangle, are incorporated into it to handling the extra computing complexity arising from the uncertainty of data. Finally, extensive experiments demonstrate that our techniques are very efficient in handling uncertain data streams. © (2013) Trans Tech Publications, Switzerland.

关键词： Decision trees

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Static analysis of list-manipulating programs via bit-vectors and numerical abstractions 13

Static analysis of list-manipulating programs via bit-vector...

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28th Annual ACM Symposium on Applied Computing, SAC 2013

作者： Chen, Liqian Li, Renjian Wu, Xueguang Wang, Ji National University of Defense Technology Changsha 410073 China National Laboratory for Parallel and Distributed Processing Changsha 410073 China

ISBN: (纸本)9781450316569

We present an approach under the framework of abstract interpretation to analyze list-manipulating programs by combining shape and numerical abstractions. The analysis automatically divides a list into non-overlapping list segments according to the reachability property of pointer variables to list nodes. The list nodes in each segment are abstracted by a bit-vector wherein each bit corresponds to a pointer variable and indicates whether the nodes can be reached by that pointer variable. Moreover, for each bit-vector, we introduce an auxiliary integer variable, namely a counter variable, to record the number of nodes in the segment abstracted by that bit-vector. On this basis, we leverage the power of numerical abstractions to discover numerical relations among counter variables, so as to infer relational length properties among list segments. Our approach stands out in its ability to find intricate properties that involve both shape and numerical information, which are important for checking program properties such as memory safety and termination. A prototype is implemented and preliminary experimental results are encouraging. Copyright 2013 ACM.

关键词： Static analysis

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Tree-Structured parallel Regeneration for Multiple Data Losses in distributed Storage Systems Based on Erasure Codes

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China Communications 2013年第4期10卷 113-125页

作者：孙伟东王意洁裴晓强 National Key Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology

To reduce the time required to complete the regeneration process of erasure codes, we propose a Tree-structured parallel Regeneration (TPR) scheme for multiple data losses in distributed storage systems. Under the scheme, two algorithms are proposed for the construction of multiple regeneration trees, namely the edge-disjoint algorithm and edge-sharing algorithm. The edge-disjoint algorithm constructs multiple independent trees, and is simple and appropriate for environments where newcomers and their providers are distributed over a large area and have few intersections. The edge-sharing algorithm constructs multiple trees that compete to utilize the bandwidth, and make a better utilization of the bandwidth, although it needs to measure the available band-width and deal with the bandwidth changes; it is therefore difficult to implement in practical systems. The parallel regeneration for multiple data losses of TPR primarily includes two optimizations: firstly, transferring the data through the bandwidth optimized-paths in a pipe-line manner; secondly, executing data regeneration over multiple trees in parallel. To evaluate the proposal, we implement an event-based simulator and make a detailed comparison with some popular regeneration methods. The quantitative comparison results show that the use of TPR employing either the edge-disjoint algorithm or edge-sharing algorithm reduces the regeneration time significantly.

关键词： distributed storage system erasure code replication regeneration tree

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Balancing CPU-GPU Collaborative High-Order CFD Simulations on the Tianhe-1A Supercomputer

Balancing CPU-GPU Collaborative High-Order CFD Simulations o...

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International Symposium on parallel and distributed processing (IPDPS)

作者： Chuanfu Xu Lilun Zhang Xiaogang Deng Jianbin Fang Guangxue Wang Wei Cao Yonggang Che Yongxian Wang Wei Liu College of Computer Science National University of Defense Technology Changsha P.R. China parallel and Distributed Systems Group Delft University of Technology Delft The Netherlands State Key Laboratory of Aerodynamics Mianyang P.R. China National University of Defense Technology Changsha Hunan CN

ISBN: (纸本)9781479938018

HOSTA is an in-house high-order CFD software that can simulate complex flows with complex geometries. Large scale high-order CFD simulations using HOSTA require massive HPC resources, thus motivating us to port it onto modern GPU accelerated supercomputers like Tianhe-1A. To achieve a greater speedup and fully tap the potential of Tianhe-1A, we collaborate CPU and GPU for HOSTA instead of using a naive GPU-only approach. We present multiple novel techniques to balance the loads between the store-poor GPU and the store-rich CPU, and overlap the collaborative computation and communication as far as possible. Taking CPU and GPU load balance into account, we improve the maximum simulation problem size per Tianhe-1A node for HOSTA by 2.3X, meanwhile the collaborative approach can improve the performance by around 45% compared to the GPU-only approach. Scalability tests show that HOSTA can achieve a parallel efficiency of above 60% on 1024 Tianhe-1A nodes. With our method, we have successfully simulated China's large civil airplane configuration C919 containing 150M grid cells. To our best knowledge, this is the first paper that reports a CPUGPU collaborative high-order accurate aerodynamic simulation result with such a complex grid geometry.

关键词： Graphics processing units Kernel Collaboration Computational fluid dynamics Computational modeling Memory management Performance evaluation

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A mathematical model for empowerment of Beowulf clusters for exascale computing

A mathematical model for empowerment of Beowulf clusters for...

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2013 11th International Conference on High Performance Computing and Simulation, HPCS 2013

作者： Mirtaheri, Seyedeh Leili Khaneghah, Ehsan Mousavi Grandinetti, Lucio Sharifi, Mohsen Center of High Performance Computing for Parallel and Distributed Processing University of Calabria Rende Italy School of Computer Engineering Iran University of Science and Technology Tehran Iran

ISBN: (纸本)9781479908363

High-performance computing (HPC) clusters are currently faced with two major challenges - namely, the dynamic nature of new generation of applications and the heterogeneity of platforms - if they are going to be useful for exascale computing. Processes running these applications may well demand unpredictable requirements and changes to system configuration and capabilities at runtime, thereby requiring fast system response without sacrificing the transparency and integrity of the reconfigured empowered system that is running on a heterogeneous platform. While a challenge in and of itself, platform heterogeneity is both useful and instrumental in the handling of unpredictable requests. The realization of such a dynamically reconfigurable and heterogeneous HPC cluster system for exascale computing requires a model to guide running processes to determine if they need empowerment of the current cluster, and if yes, by how much. To show the feasibility of empowerment of traditional HPC clusters for exascale computing, we have selected Beowulf as a noble candidate cluster and present a mathematical model for the empowerment of Beowulf clusters for exascale computing (EBEC). We have developed the model in line with Beowulf's cluster approach and by using vector space algebra. In contrast to traditional hardware-oriented approaches to improvise the performance of clusters, we use a software approach to the development of the proposed model by emphasizing processes, which act as the creators of the cluster and thus should decide on system (re)configuration, as the principal building blocks of the system. We have also adopted a new approach to heterogeneity by considering heterogeneity at different levels including hardware, system software, application software, and system functionality. In addition to support for heterogeneity and dynamic reconfiguration, the proposed model includes support for scalability that is crucial to exascale computing too. © 2013 IEEE.

关键词： Vector spaces

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Pruning false positives of static data-race detection via thread specialization

Pruning false positives of static data-race detection via th...

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10th International Symposium on Advanced parallel processing Technologies, APPT 2013

作者： Chen, Chen Lu, Kai Wang, Xiaoping Zhou, Xu Fang, Li National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China College of Computer National University of Defense Technology Changsha China Information Center National University of Defense Technology Changsha China

ISBN: (纸本)9783642452925

Static data-race detection is a powerful tool by providing clues for dynamic approaches to only instrument certain memory accesses. However, static data-race analysis suffers from high false positive rate. A key reason is that static analysis overestimates the set of shared objects a thread can access. We propose thread specialization to distinguish threads statically. By fixing the number of threads as well as the ID assigned to each thread, a program can be transformed to a simplified version. Static data-race analysis on this simplified program can infer the range of addresses accessed by each thread more accurately. Our approach prunes false positives by an average of 89.2% and reduces dynamic instrumentation by an average of 63.4% in seven benchmarks. © 2013 Springer-Verlag.

关键词： Static analysis

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A Trusted Remote Attestation Model Based on Trusted Computing

A Trusted Remote Attestation Model Based on Trusted Computin...

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IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom)

作者： Yue Yu Huaimin Wang Bo Liu Gang Yin National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

ISBN: (纸本)9781479914449

Traditional security protocols can not be trusted in some application scenarios of high security level because the endpoints integrity is ignored. In this paper, we propose a novel trusted remote attestation model which combines the secure channel and the integrity measurement architecture of trusted computing. We design and implement a prototype system based on a mature security protocol, Transport Layer Security (TLS) protocol, integrated with integrity report provided by trusted platform module (TPM). The TLS protocol guarantees the security of data exchange process and the integrity report of TPM provides the evidence about the trustworthiness and the security state of the communication endpoints. Compared by traditional approaches, our method is more efficient and can be deployed in large scale systems easily.

关键词： Protocols Servers Principal component analysis Authentication Computer architecture Privacy

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Data storage optimization of application-level checkpointing on heterogeneous systems

Data storage optimization of application-level checkpointing...

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IEEE Conference Anthology

作者： Jia Jia Wei Song National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China

General purpose GPU's (GPGPU) appearance made it possible that heterogeneous computing can be used by human beings. And it's also produce a reform for GPU's general purpose computing and parallel computing. Heterogeneous Systems has been adopted by large-scale of high-performance computers. Nowadays, fault tolerance technique is necessary among these large-scale kinds of scientific computing, but in a few years of GPGPU and heterogeneous system appearance, there is not an effective fault tolerance method come out, therefore, towards this situation, this paper will apply the traditional fault tolerance technique—application-level checkpointing to heterogeneous system. Cause the main solution of reducing overhead of the application-level checkpointing is reducing checkpoint data size, so after analyzing the heterogeneous system and GPGPU program, we propose a method to optimize the data storage of application-level checkpointing technique and validate its optimization by experiments.

关键词： Graphics processing units Checkpointing Kernel Fault tolerance Fault tolerant systems Optimization Hardware

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