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FAAD:an unsupervised fast and accurate anomaly detection method for a multi-dimensional sequence over data stream

Frontiers of Information Technology & Electronic Engineering 2019年第3期20卷 388-404页

作者： Bin LI Yi-jie WANG Dong-sheng YANG Yong-mou LI Xing-kong MA Science and Technology on Parallel and Distributed Processing Laboratory College of ComputerNational University of Defense Technology Block Chain Research Institute of LianLian Pay

Recently, sequence anomaly detection has been widely used in many fields. Sequence data in these fields are usually multi-dimensional over the data stream. It is a challenge to design an anomaly detection method for a multi-dimensional sequence over the data stream to satisfy the requirements of accuracy and high speed. It is because:(1) Redundant dimensions in sequence data and large state space lead to a poor ability for sequence modeling;(2) Anomaly detection cannot adapt to the high-speed nature of the data stream, especially when concept drift occurs, and it will reduce the detection rate. On one hand, most existing methods of sequence anomaly detection focus on the single-dimension sequence. On the other hand, some studies concerning multi-dimensional sequence concentrate mainly on the static database rather than the data stream. To improve the performance of anomaly detection for a multi-dimensional sequence over the data stream, we propose a novel unsupervised fast and accurate anomaly detection(FAAD) method which includes three algorithms. First, a method called "information calculation and minimum spanning tree cluster" is adopted to reduce redundant dimensions. Second, to speed up model construction and ensure the detection rate for the sequence over the data stream, we propose a method called"random sampling and subsequence partitioning based on the index probabilistic suffix tree." Last, the method called "anomaly buffer based on model dynamic adjustment" dramatically reduces the effects of concept drift in the data stream. FAAD is implemented on the streaming platform Storm to detect multi-dimensional log audit *** with the existing anomaly detection methods, FAAD has a good performance in detection rate and speed without being affected by concept drift.

关键词： Data stream Multi-dimensional sequence Anomaly detection Concept drift Feature selection

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A novel approach for recommending semantically linkable issues in GitHub projects

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Science China(Information Sciences) 2019年第9期62卷 202-204页

作者： Yang ZHANG Yiwen WU Tao WANG Huaimin WANG Key Laboratory of Parallel and Distributed Computing National University of Defense Technology College of Computer National University of Defense Technology

Dear editor,GitHub1)is a web-based project hosting platform which was launched in 2008 and has become one of the premier open-source development sites [1]. During the software development process of GitHub projects, issue reports, as an important development knowledge, are likely to be related as they contain relevant information. One

关键词： GitHub A novel approach for recommending semantically linkable issues in GitHub projects

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A hyper-cube based P2P information service for data grid

A hyper-cube based P2P information service for data grid

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5th International Conference on Grid and Cooperative Computing, GCC 2006

作者： Ren, Hao Wang, Zhiying Liu, Zhong National Laboratory for Parallel and Distributed Processing NUDT China

ISBN: (纸本)0769526942

There are many researches use peer-to-peer model to organize the Grid Information Service (GIS) and have been testified which be able to improve scalability and reliability of Grid environment. However, Data Grid Information Service (DGIS) has its special requirements and all approaches of PIP model used in GIS cannot be applied to DGIS. In this paper, we propose a new approach for DGIS that imposes a deterministic P2P shape based on hypercube topology, which allows for very efficient query broadcasting. Furthermore, we proposed a transposition algorithm to optimize the overlay network's topology according to the access statistics between peers, making the peers always access each other become neighbor by transposing peer's place. The simulation shows that the transposition algorithm could significant improve searches efficiency. © 2006 IEEE.

关键词： Information services

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Towards a framework for scalable model checking of concurrent C programs

Towards a framework for scalable model checking of concurren...

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2nd International Symposium on Leveraging Applications of Formal Methods, Verification and Validation, ISoLA 2006

作者： Ji, Wang Yi, Xiaodong Yang, Xuejun National Laboratory for Parallel and Distributed Processing Changsha China

ISBN: (纸本)0769530710

The paper presents a novel framework for scalable model checking of concurrent C programs. With the idea of verification reuse, it shows an integrated approach to efficient reduction of state space by abstraction, symbolic representation and dynamic partial-order reduction (DPOR) techniques. The framework is founded on an over-approximated model of the concurrent program by variable abstraction, and combines DPOR with lightweight symbolic execution to generate the symbolic conditions for all locations, called α-conditions, which are intended for verification reuse. The α-conditions of a location are weak approximation of the conditions that must be satisfied at that location so as to guarantee the temporal safety properties to be verified. These conditions will be checked for reusing the previous exploration in verification, and will be iteratively refined under the guidance of spurious counterexamples. The presented framework is demonstrated by several experiments including a concurrent software system whose server and client processes are derived from openssl-0.9.6c C source codes implementing the SSL protocol. © 2007 IEEE.

关键词： Model checking

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Combining model and iterative compilation for program performance optimization

Journal of Software

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Journal of Software 2009年第3期4卷 240-246页

作者： Lu, Pingjing Che, Yonggang Wang, Zhenghua National Laboratory for Parallel and Distributed Processing School of Computer National University of Defense Technology Changsha 410073 China

The performance gap for high performance applications has been widening over time. High level program transformations are critical to improve applications' performance, many of which concern the determination of optimal values for transformation parameters, such as loop unrolling and blocking. Static approaches achieve these values based on analytical models that are hard to achieve because of increasing architecture complexity and code structures. Recent iterative compilation approaches achieve it by executing different versions of the program on actual platforms and select the one that renders best performance, outperforming static compilation approaches significantly. But the expensive compilation cost has limited their application scope to embedded applications and a small group of math kernels. This paper proposes a combinative approach--Combining Model and Iterative Compilation for Program Performance Optimization (CMIC). Such an approach first constructs a program optimization transformation model based on hardware performance counters to decide how and when to apply transformations, and then selects the optimal transformation parameters using Nelder-Mead simplex algorithm. Experimental results show that our approach can effectively improve programs' floating-point performance, reducing programs' runtime, therefore, lessening the performance gap for high-performance applications. © 2009 ACADEMY PUBLISHER.

关键词： Digital arithmetic

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Jammer Localization for Wireless Sensor Networks

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电子学报(英文版) 2011年第4期20卷 735-738页

作者： SUN Yanqiang WANG Xiaodong ZHOU Xingming National Key Laboratory for Parallel and Distributed Processing College of Computer Science National University of Defense Technology Changsha China

Jamming attack can severely affect the performance of Wireless sensor networks (WSNs) due to the broadcast nature of wireless medium. In order to localize the source of the attacker, we in this paper propose a jammer localization algorithm named as Minimum-circlecovering based localization (MCCL). Comparing with the existing solutions that rely on the wireless propagation parameters, MCCL only depends on the location information of sensor nodes at the border of the jammed region. MCCL uses the plane geometry knowledge, especially the minimum circle covering technique, to form an approximate jammed region, and hence the center of the jammed region is treated as the estimated position of the jammer. Simulation results showed that MCCL is able to achieve higher accuracy than other existing solutions in terms of jammer's transmission range and sensitivity to nodes' density.

关键词：无线传感器网络干扰定位传感器节点位置信息覆盖技术定位算法无线传播几何知识

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Fast garment simulation with aid of hybrid bones

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Journal of Central South University 2015年第6期22卷 2218-2226页

作者：吴博陈寅徐凯程志全熊岳山 College of Computer National University of Defense Technology Science and Technology on Parallel and Distributed Processing Laboratory (National University of Defense Technology) Avatar Science Company

A data-driven method was proposed to realistically animate garments on human poses in reduced space. Firstly, a gradient based method was extended to generate motion sequences and garments were simulated on the sequences as our training data. Based on the examples, the proposed method can fast output realistic garments on new poses. Our framework can be mainly divided into offline phase and online phase. During the offline phase, based on linear blend skinning(LBS), rigid bones and flex bones were estimated for human bodies and garments, respectively. Then, rigid bone weight maps on garment vertices were learned from examples. In the online phase, new human poses were treated as input to estimate rigid bone transformations. Then, both rigid bones and flex bones were used to drive garments to fit the new poses. Finally, a novel formulation was also proposed to efficiently deal with garment-body penetration. Experiments manifest that our method is fast and accurate. The intersection artifacts are fast removed and final garment results are quite realistic.

关键词： data-driven linear blend skinning hybrid bones interactive

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Superscalar communication: A runtime optimization for distributed applications

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Science China(Information Sciences) 2010年第10期53卷 1931-1946页

作者： LI HuiBa , LIU ShengYun, PENG YuXing, LI DongSheng, ZHOU HangJun & LU XiCheng National laboratory for parallel and distributed Processing, National University of Defense Technology, Changsha 410073, China 1. National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China

Building distributed applications is difficult mostly because of concurrency management. Existing approaches primarily include events and threads. Researchers and developers have been debating for decades to prove which is superior. Although the conclusion is far from obvious, this long debate clearly shows that neither of them is perfect. One of the problems is that they are both complex and error-prone. Both events and threads need the programmers to explicitly manage concurrencies, and we believe it is just the source of difficulties. In this paper, we propose a novel approach—superscalar communication, in which concurrencies are automatically managed by the runtime system. It dynamically analyzes the programs to discover potential concurrency opportunities; and it dynamically schedules the communication and the computation tasks, resulting in automatic concurrent execution. This approach is inspired by the idea of superscalar technology in modern microprocessors, which dynamically exploits instruction-level parallelism. However, hardware superscalar algorithms do not fit software in many aspects, thus we have to design a new scheme completely from scratch. Superscalar communication is a runtime extension with no modification to the language, compiler or byte code, so it is good at backward compatibility. Superscalar communication is likely to begin a brand new research area in systems software, which is characterized by dynamic optimization for networking programs.

关键词： network programming concurrency event thread superscalar

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Game-based software errors detection

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Advances in Information Sciences and Service Sciences 2012年第15期4卷 426-433页

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

Software security is one of the most important aspects of software quality, but errors in programs are still inevitable. Despite the development of static and dynamic analysis, the useful but costly manual analysis is still heavily used. In this paper, we propose a human computation game based software error detection mechanism. The purpose of our mechanism is to improve the effectiveness and efficiency of manual error detection. The framework includes four main steps: 1) get all suspicious error locations by static tools according to different security properties;2) slice the programs from each error location;3) construct games for each slice and show them to players;4) collect game information and generate the final error report. We evaluate our approach by instantiating it for detecting errors of buffer overflow. The results show that our technique is successful in practice.

关键词： Error detection

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MPtostream:an OpenMP compiler for CPU-GPU heterogeneous parallel systems

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Science China(Information Sciences) 2012年第9期55卷 1961-1971页

作者： YANG XueJun,TANG Tao ,WANG GuiBin,JIA Jia & XU XinHai National laboratory for parallel and distributed Processing,National University of Defense Technology,Changsha 410073,China 1. National Laboratory for Parallel and Distributed Processing National University of Defense Technology Changsha 410073 China

In light of GPUs’ powerful floating-point operation capacity,heterogeneous parallel systems incorporating general purpose CPUs and GPUs have become a highlight in the research field of high performance computing(HPC).However,due to the complexity of programming on GPUs,porting a large number of existing scientific computing applications to the heterogeneous parallel systems remains a big *** OpenMP programming interface is widely adopted on multi-core CPUs in the field of scientific *** effectively inherit existing OpenMP applications and reduce the transplant cost,we extend OpenMP with a group of compiler directives,which explicitly divide tasks among the CPU and the GPU,and map time-consuming computing fragments to run on the GPU,thus dramatically simplifying the *** have designed and implemented MPtoStream,a compiler of the extended OpenMP for AMD’s stream processing *** experimental results show that programming with the extended directives deviates from programming with OpenMP by less than 11% modification and achieves significant speedup ranging from 3.1 to 17.3 on a heterogeneous system,incorporating an Intel Xeon E5405 CPU and an AMD FireStream 9250 GPU,over the execution on the Xeon CPU alone.

关键词： GPGPU stream OpenMP compiler

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