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Experimental verification of the parasitic bipolar amplification effect in PMOS single event transients

Chinese Physics B 2014年第7期23卷 775-779页

作者：何益百陈书明 College of Computer National University of Defense Technology Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology

The contribution of parasitic bipolar amplification to SETs is experimentally verified using two P-hit target chains in the normal layout and in the special layout. For PMOSs in the normal layout, the single-event charge collection is composed of diffusion, drift, and the parasitic bipolar effect, while for PMOSs in the special layout, the parasitic bipolar junction transistor cannot turn on. Heavy ion experimental results show that PMOSs without parasitic bipolar amplification have a 21.4% decrease in the average SET pulse width and roughly a 40.2% reduction in the SET cross-section.

关键词： single event effect single event transient parasitic bipolar amplification heavy ion experiments

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Scalability of 3D deterministic particle transport on the Intel MIC architecture

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Nuclear Science and Techniques 2015年第5期26卷 88-97页

作者：王庆林刘杰龚春叶邢座程 Science and Technology on Parallel and Distributed Processing Laboratory National University of Defense Technology Science and Technology on Space Physics Laboratory

The key to large-scale parallel solutions of deterministic particle transport problem is single-node computation performance. Hence, single-node computation is often parallelized on multi-core or many-core computer architectures. However, the number of on-chip cores grows quickly with the scale-down of feature size in semiconductor technology. In this paper, we present a scalability investigation of one energy group time-independent deterministic discrete ordinates neutron transport in 3D Cartesian geometry(Sweep3D) on Intel's Many Integrated Core(MIC) architecture, which can provide up to 62 cores with four hardware threads per core now and will own up to 72 in the future. The parallel programming model, Open MP, and vector intrinsic functions are used to exploit thread parallelism and vector parallelism for the discrete ordinates method, respectively. The results on a 57-core MIC coprocessor show that the implementation of Sweep3 D on MIC has good scalability in performance. In addition, the application of the Roofline model to assess the implementation and performance comparison between MIC and Tesla K20 C Graphics processing Unit(GPU) are also reported.

关键词：计算机体系结构可扩展性粒子输运三维几何英特尔麦克风离散坐标法计算性能

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Prediction-based federated management of multi-scale resources in cloud

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Advances in Information Sciences and Service Sciences 2012年第6期4卷 324-334页

作者： Shi, Peichang Wang, Huaimin Yin, Gang Lu, Fengshun Wang, Tianzuo National Laboratory for Parallel and Distributed Processing College of Computer National University of Defense Technology Changsha China

The connotation of the cloud resources have been extended to be multi-scale resources, which includes central resources as presented by data center, edge resources as presented by Content Delivery Network (CDN) and end resources as presented by Peer-to-Peer (P2P). Under the development situation of the scale of the cloud services, it is difficult to provide services (e.g. streaming distribution) with guaranteed QoS only relying on single type of resource (e.g. central resources) to geo-distributed users. Therefore, making multi-resources cooperative to provide reliable services is necessary. However, it is a great challenge to realize Federated Management of Multi-scale Resources (FMMR). In this research, we propose the idea of prediction-based FMMR, and present the problem formulation introducing economic profit from the perspective of CDN operators. Then, we present the method of Time-series Prediction based on Wavelet Analysis (TPWA) to predict the resource requirements of streaming cloud services in CDN. Finally, the predictability of the resource requirement pattern of the streaming cloud service and the effectiveness of our proposed method have been verified, based on the traces collected from a real CDN entity.

关键词： Quality of service

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Exploiting a depth context model in visual tracking with correlation filter

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Frontiers of Information Technology & Electronic Engineering 2017年第5期18卷 667-679页

作者： Zhao-yun CHEN Lei LUO Da-fei HUANG Mei WEN Chun-yuan ZHANG College of Computer National University of Defense TechnologyChangsha 410073China National Key Laboratory of Parallel and Distributed Processing Changsha 410073China

Recently correlation filter based trackers have attracted considerable attention for their high computational efficiency. However, they cannot handle occlusion and scale variation well enough. This paper aims at preventing the tracker from failure in these two situations by integrating the depth information into a correlation filter based tracker. By using RGB-D data, we construct a depth context model to reveal the spatial correlation between the target and its surrounding regions. Furthermore, we adopt a region growing method to make our tracker robust to occlusion and scale variation. Additional optimizations such as a model updating scheme are applied to improve the performance for longer video sequences. Both qualitative and quantitative evaluations on challenging benchmark image sequences demonstrate that the proposed tracker performs favourably against state-of-the-art algorithms.

关键词： Visual tracking Depth context model Correlation filter Region growing

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Bidirectional Influence and Interaction for Multiagent Reinforcement Learning

IEEE Transactions on Artificial Intelligence

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IEEE Transactions on Artificial Intelligence 2024年第10期5卷 4984-4995页

作者： Sun, Shaoqi Xu, Kele Feng, Dawei Ding, Bo National University of Defense Technology National Key Laboratory of Parallel and Distributed Processing Changsha410003 China

In recent years, multiagent reinforcement learning (MARL) has demonstrated considerable potential across diverse applications. However, in reinforcement learning environments characterized by sparse rewards, the scarcity of reward signals may give rise to reward conflicts among agents. In these scenarios, each agent tends to compete to obtain limited rewards, deviating from collaborative efforts aimed at achieving collective team objectives. This not only amplifies the learning challenge but also imposes constraints on the overall learning performance of agents, ultimately compromising the attainment of team goals. To mitigate the conflicting competition for rewards among agents in MARL, we introduce the bidirectional influence and interaction (BDII) MARL framework. This innovative approach draws inspiration from the collaborative ethos observed in human social cooperation, specifically the concept of "sharing joys and sorrows." The fundamental concept behind BDII is to empower agents to share their individual rewards with collaborators, fostering a cooperative rather than competitive behavioral paradigm. This strategic shift aims to resolve the pervasive issue of reward conflicts among agents operating in sparse-reward environments. BDII incorporates two key factors—namely, the Gaussian kernel distance between agents (physical distance) and policy diversity among agents (logical distance). The two factor collectively contribute to the dynamic adjustment of reward allocation coefficients, culminating in the formation of reward distribution weights. The incorporation of these weights facilitates the equitable sharing of agents’ contributions to rewards, promoting a cooperative learning environment. Through extensive experimental evaluations, we substantiate the efficacy of BDII in addressing the challenge of reward conflicts in MARL. Our research findings affirm that BDII significantly mitigates reward conflicts, ensuring that agents consistently align with the origi

关键词： Reinforcement learning

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Auxo: an architecture-centric framework supporting the online tuning of software adaptivity

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Science China(Information Sciences) 2015年第9期58卷 31-45页

作者： WANG HuaiMin DING Bo SHI DianXi CAO JianNong Alvin T.S.Chan National Key Laboratory of Parallel and Distributed Processing College of ComputerNational University of Defense Technology Department of Computing Hong Kong Polytechnic University

Adaptivity is the capacity of software to adjust itself to changes in its environment. A common approach to achieving adaptivity is to introduce dedicated code during software development stage. However,since those code fragments are designed a priori, self-adaptive software cannot handle situations adequately when the contextual changes go beyond those that are originally anticipated. In this case, the original builtin adaptivity should be tuned. For example, new code should be added to provide the capacity to sense the unexpected environment or to replace outdated adaptation decision logic. The technical challenges in this process, especially that of tuning software adaptivity at runtime, cannot be understated. In this paper,we propose an architecture-centric application framework for self-adaptive software named Auxo. Similar to existing work, our framework supports the development and running of self-adaptive software. Furthermore,our framework supports the tuning of software adaptivity without requiring the running self-adaptive software to be terminated. In short, the architecture style that we are introducing can encapsulate not only general functional logic but also the concerns in the self-adaptation loop(such as sensing, decision, and execution)as architecture elements. As a result, a third party, potentially the operator or an augmented software entity equipped with explicit domain knowledge, is able to dynamically and flexibly adjust the self-adaptation concerns through modifying the runtime software architecture. To truly exercise, validate, and evaluate our approach,we describe a self-adaptive application that was deployed on the framework, and conducted several experiments involving self-adaptation and the online tuning of software adaptivity.

关键词： software architecture self-adaptive software architecture style application framework software adaptation

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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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Slicing hierarchical automata for model checking UML statecharts 4th

Slicing hierarchical automata for model checking UML statech...

引用

4th International Conference on Formal Engineering Methods, ICFEM 2002

作者： Ji, Wang Wei, Dong Qi, Zhi-Chang National Laboratory for Parallel and Distributed Processing China

ISBN: (纸本)9783540000297

Hierarchical Automata has been widely used in modeling dynamic aspects of reactive software, such as in UML Statecharts. At the same time, model checking is an automatic technique to ensure the correctness of software models, where state space explosion is the main obstacle to applying this technique in large scale applications. The paper presents a method for slicing hierarchical automata with respect to properties to be verified. The considered formalism is Extended Hierarchical Automata (EHA), in which a set of dependence relations is specified after analyzing characteristics such as hierarchy, concurrency and synchronization. We present the algorithm of slicing EHA based on the slicing criterion in terms of states and transitions. The algorithm can remove the hierarchies and concurrent states which are irrelevant to the property, and reduce the state space efficiently in model checking UML Statecharts. © Springer-Verlag Berlin Heidelberg 2002.

关键词： Model checking

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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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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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