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Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) 2014年 8723卷 101-117页

作者： Chen, Liqian Liu, Jiangchao Mine, Antoine Kapur, Deepak Wang, Ji National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha China École Normale Supérieure Paris France CNRS France University of New Mexico NM United States

The octagon abstract domain, devoted to discovering octagonal constraints (also called Unit Two Variable Per Inequality or UTVPI constraints) of a program, is one of the most commonly used numerical abstractions in practice, due to its quadratic memory complexity and cubic time complexity. However, the octagon domain itself is restricted to express convex sets and has limitations in handling non-convex properties which are sometimes required for proving some numerical properties in a program. In this paper, we intend to extend the octagon abstract domain with absolute value, to infer certain non-convex properties by exploiting the absolute value function. More precisely, the new domain can infer relations of the form {±X ± Y ≤ c, ±X ± |Y| ≤ d,±|X|±|Y| ≤ e}. We provide algorithms for domain operations such that the new domain still enjoys the same asymptotic complexity as the octagon domain. Moreover, we present an approach to support strict inequalities over rational or real-valued variables in this domain, which also fits for the octagon domain. Experimental results of our prototype are encouraging;The new domain is scalable and able to find non-convex invariants of interest in practice but without too much overhead (compared with that using octagons). © Springer International Publishing Switzerland 2014.

关键词： Set theory

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Constraint-Relaxation Approach for Nonnegative Matrix Factorization: A Case Study

Constraint-Relaxation Approach for Nonnegative Matrix Factor...

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IEEE International Conference on Systems, Man and Cybernetics

作者： Jue Wang Naiyang Guan Xuhui Huang Zhigang Luo Science and Technology on Parallel and Distributed Processing Laboratory College of Computer National University of Defense Technology Hunan P.R. China Department of Computer Science and Techonoly College of Computer National University of Defense Technology Hunan P.R. China

ISBN: (纸本)9781479986989

Nonnegative matrix factorization (NMF) is a powerful technique for dimensionality reduction. Conventional NMF algorithms usually keep the matrices W and H nonnegative while iterating. However, to get the NMF of a matrix, it's unnecessary to force the temporary solutions in iterations nonnegative. In this paper, we propose a two-staged approach for NMF. At the relaxation stage, the nonnegative constraint of temporary solutions is relaxed and a real valued matrix factorization is generated. At the constraint stage, the real valued matrix factorization is transformed to a nonnegative matrix factorization by an invertible linear transformation. Based on this approach, we study on exact nonnegative matrix factorization when rank=2. We proved that, given two real valued matrices of rank=2, there exists an invertible linear transformation which can transform the real valued matrices to nonnegative matrices with their product stable. We propose an algorithm to find out the transformation. When rank is higher than 2, this kind of transformation may not exist. In the experiments, it's showed that this approach can reach a nonnegative matrix factorization with lower reconstruction error than conventional methods, and the technique for rank=2 exact NMF works well.

关键词： Algorithm design and analysis Matrix decomposition Additives Computers Transforms Matrix converters Clustering algorithms

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DREAMS: Dynamic resource allocation for MapReduce with data skew

DREAMS: Dynamic resource allocation for MapReduce with data ...

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IFIP/IEEE International Symposium on Integrated Network Management

作者： Zhihong Liu Qi Zhang Mohamed Faten Zhani Raouf Boutaba Yaping Liu Zhenghu Gong College of Computer National University of Defense Technology Changsha China David R. Cheriton School of Computer Science University of Waterloo Waterloo ON Canada Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha Hunan China

ISBN: (纸本)9781479982424

MapReduce has become a popular model for large-scale data processing in recent years. However, existing MapRe-duce schedulers still suffer from an issue known as partitioning skew, where the output of map tasks is unevenly distributed among reduce tasks. In this paper, we present DREAMS, a framework that provides run-time partitioning skew mitigation. Unlike previous approaches that try to balance the workload of reducers by repartitioning the intermediate data assigned to each reduce task, in DREAMS we cope with partitioning skew by adjusting task run-time resource allocation. We show that our approach allows DREAMS to eliminate the overhead of data repartitioning. Through experiments using both real and synthetic workloads running on a 11-node virtual virtualised Hadoop cluster, we show that DREAMS can effectively mitigate negative impact of partitioning skew, thereby improving job performance by up to 20.3%.

关键词： Resource management Containers Predictive models Mathematical model Monitoring Biomedical monitoring Yarn

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NVLAN: A Novel VLAN Technology for Scalable Multi-tenant Datacenter Networks 2

NVLAN: A Novel VLAN Technology for Scalable Multi-tenant Dat...

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2nd International Conference on Advanced Cloud and Big Data, CBD 2014

作者： Hu, Yang Li, Huiba Peng, Yuxing Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Computer Science Department China

ISBN: (纸本)9781479980857

Nowadays, cloud providers of 'Infrastructure as a service' require datacenter networks to support virtualization and multi-tenancy at large scale, while it brings a grand challenge to datacenters. Traditional network technologies of datacenters and common commodity devices of network can not meet these new needs. In this paper, we present NVLAN, a novel VLAN technology for scalable multi-tenant datacenter networks. NVLAN eliminates the quantity limitation of logic isolated networks on VLAN through a slight modification. NVLAN can be applied to very large-scale datacenter networks, without the need of expensive and dedicated switches. Through encapsulation of tenant's packets, NVLAN provides tenants with full address space virtualization to configure their own logic network. We implemented NVLAN on a test bed, and demonstrated that it can be scaled up to large numbers of multi-tenant networks with negligible overhead. © 2014 IEEE.

关键词： Virtualization

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AUModel: A conceptual model for adaptive software 5

AUModel: A conceptual model for adaptive software

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2014 5th IEEE International Conference on Software Engineering and Service Science, ICSESS 2014

作者： Liu, Hui Ding, Bo Shi, Dianxi Wang, Huaimin National Key Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Changsha Hunan410073 China

ISBN: (纸本)9781479932788

Pervasive software should be able to adapt itself to the changing environments and user requirements. Obviously, it will bring great challenges to the software engineering practice. This paper proposes AUModel, a conceptual model for adaptive software, which takes adaptability as an inherent feature and can act as the foundation of the engineering process. By introducing AUModel, the reuse of software adaptation infrastructure as well as the separation of adaptation concerns are enabled, which can facilitate both the development and maintenance of adaptive software. This paper also presents our initial attempts to realize this model, including a middleware prototype to support this model and an application to validate its effectiveness. © 2014 IEEE.

关键词： Middleware

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RTC: Link schedule based MAC design in multi-hop wireless network

RTC: Link schedule based MAC design in multi-hop wireless ne...

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International Conference on Quality of Service in Heterogeneous Wired/Wireless Networks (QSHINE)

作者： Xuan Dong Yinjia Huo Chunsheng Zhu Shaohe Lv Wenxiang Li Xiaodong Wang Department of Electrical and Computer Engineering The University of British Columbia Vancouver BC Canada National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha China Engineering Research Center for Metallurgical Automation and Detecting Technology of Ministry of Education Wuhan University of Science and Technology Wuhan China

ISBN: (纸本)9781479982172

The performance of an ad-hoc network is greatly limited by collisions due to hidden terminals. In this paper, we propose a receiver tracking contention (RTC) scheme, which achieves high throughput by allowing the receivers to assist for channel contention. In RTC, link is the basic unit for channel access contention. Specifically, transmitter is used to contend for the channel and receiver is used to announce the potential collision. Based on INT message coding scheme, transmitter and its corresponding receiver can be well coordinated. In such mechanism, hidden terminals are avoided and exposed terminals are encouraged to transmit simultaneously. Based on OFDM modulation, RTC packets several subcarriers as subcontention unit and operates channel contention over multiple subcontention units. Furthermore, each subcontention unit maintains a transmission set, where collision-free links are allowed to merged into the transmission set In this case, the transmission set of subcontention unit can be aggregated after each contention period. When the subcontention unit i is the smallest index of non-empty subcontention unit, the transmission set of unit i will win the channel contention and transmitters of unit i will start to transmit in the following data transmission period. Analysis and simulation results show that RTC achieves a notable throughput gain over Back2f as high as 190% through simulation.

关键词： Receivers OFDM Transmitters Electronics packaging

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Synchronization error detection of MPI programs by symbolic execution 21

Synchronization error detection of MPI programs by symbolic ...

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21st Asia-Pacific Software Engineering Conference, APSEC 2014

作者： Fu, Xianjin Chen, Zhenbang Huang, Chun Dong, Wei Wang, Ji Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha China College of Computer National University of Defense Technology Changsha China

ISBN: (纸本)9781479974252

Asynchrony based overlapping of computation and communication is commonly used in MPI applications. However, this overlapping introduces synchronization errors frequently in asynchronous MPI programming. In this paper, we propose a symbolic execution based method for detecting input-related synchronization errors. The path space of an MPI program is systematically explored, and the related operations of the synchronization errors in the program are checked specifically. In addition, two optimizations are proposed to improve the efficiency. We have implemented our method as a prototype tool based on the symbolic executor Cloud9. The results of the extensive experiments indicate the effectiveness of our method. © 2014 IEEE.

关键词： Synchronization

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Effective hierarchical routing algorithm for large-scale wireless mobile networks

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Journal of Networks 2014年第2期9卷 344-352页

作者： Yan, Guofeng Peng, Yuxing Hu, Ying Liu, Junyi School of Computer and Communication Hunan Institute of Engineering Hunan 411104 China Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha 410073 China School of Computer National University of Defense Technology Changsha 410073 China

The growing interest in wireless mobile network techniques has resulted in many routing protocol proposals. The unpredictable motion and the unreliable behavior of mobile nodes is one of the key issues in wireless mobile network. Virtual mobile node (VMN) consists of robust virtual nodes that are both predictable and reliable. Based on VMN, in this paper, we present a hierarchical routing algorithm, i.e., EHRA-WAVE, for large-scale wireless mobile networks. By using mobile WAVE technology, a routing path can be found rapidly between VMNs without accurate topology information. We introduce the routing algorithm and the implementation issues of the proposed EHRA-WAVE routing algorithm. Finally, we evaluate the performance of EHRA-WAVE through experiments, and compare the performance on VMN failure and message delivery ratio using hierarchical and non-hierarchical routing methods. However, due to the large amounts WAVE flooding, EHRA-WAVE results in too large load which would impede the application of the EHRA-WAVE algorithm. Therefore, the further routing protocol focuses on minimizing the number of WAVE using hierarchical structures in large-scale wireless mobile networks. © 2014 Academy Publisher.

关键词： Quality of service

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VAWS: Constructing trusted open computing system of mapreduce with verified participants

VAWS: Constructing trusted open computing system of mapreduc...

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作者： Ding, Yan Wang, Huaimin Wei, Lifeng Chen, Songzheng Fu, Hongyi Xu, Xinhai School of Computer National University of Defense Technology Changsha HN China National Laboratory for Parallel and Distributed Processing National Univ. of Defense Technology Changsha HN China

MapReduce is commonly used as a parallel massive data processing model. When deploying it as a service over the open systems, the computational integrity of the participants is becoming an important issue due to the untrustworthy workers. Current duplication-based solutions can effectively solve non-collusive attacks, yet most of them require a centralized worker to re-compute additional sampled tasks to defend collusive attacks, which makes the worker a bottleneck. In this paper, we try to explore a trusted worker scheduling framework, named VAWS, to detect collusive attackers and assure the integrity of data processing without extra re-computation. Based on the historical results of verification, we construct an Integrity Attestation Graph (IAG) in VAWS to identify malicious mappers and remove them from the framework. To further improve the efficiency of identification, a verification-couple selection method with the IAG guidance is introduced to detect the potential accomplices of the confirmed malicious worker. We have proven the effectiveness of our proposed method on the improvement of system performance in theoretical analysis. Intensive experiments show the accuracy of VAWS is over 97% and the overhead of computation is closed to the ideal value of 2 with the increasing of the number of map tasks in our scheme. Copyright © 2014 The Institute of Electronics, Information and Communication Engineers.

关键词： MapReduce

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Array receiving scheme for ultra-wideband WSN OFDM signals

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Ruan Jian Xue Bao/Journal of Software 2014年 25卷 30-38页

作者： Du, Xiao-Li Lü, Shao-He Wang, Xiao-Dong Zhou, Xing-Ming Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Changsha410073 China

This paper proposes an array receiving scheme for ultra-wideband (UWB) OFDM signals in WSN networks. The major feature of the proposed scheme is recovering the UWB OFDM signal by frequency stitching. Firstly, the UWB OFDM signal is divided into multiple sub-bands. Every two adjacent sub-bands share at least one overlapped subcarrier(s), which is used for time alignment later. A sub-signal of the UWB OFDM signal is received on each sub-band by a narrow-band receiver. The received data sets of narrow-band receivers are time aligned by performing peak value alignment retrieval (PVAR) on the shared subcarriers. Then the UWB OFDM signal is recovered by fusing the received data sets according to the result of PVAR. As the implementation of narrow-band receivers only needs low-speed ADCs, the challenge of high-speed ADC in traditional UWB OFDM receiver is addressed. Extensive simulations are performed to demonstrate the validity of the proposed scheme and further look into three performance metrics: (1) synchronization error-tolerance, (2) extensibility, (3) performance under different SNR values. ©2014 ISCAS.

关键词： Wireless sensor networks

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