检索结果-内蒙古大学图书馆

Uniform convergence of multigrid finite element method for time-dependent riesz tempered fractional problem

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Chen, Minghua Bu, Weiping Qi, Wenya Wang, Yantao School of Mathematics and Statistics Gansu Key Laboratory of Applied Mathematics and Complex Systems Lanzhou University Lanzhou730000 China School of Mathematics and Computational Science Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan411105 China South University of Science and Technology of China Shenzhen518055 China

In this article a theoretical framework for the Galerkin finite element approximation to the time-dependent Riesz tempered fractional problem is provided without the fractional regularity assumption. Because the time-dependent problems should become easier to solve as the time step τ → 0, which correspond to the mass matrix dominant [R. E. Bank and T. Dupont, Math. Comp., 153 (1981), pp. 35-51]. Based on the introduced and analysis of the fractional τ-norm, the uniform convergence estimates of the V-cycle multigrid method with the time-dependent fractional problem is strictly proved, which means that the convergence rate of the V-cycle MGM is independent of the mesh size h and the time step τ. The numerical experiments are performed to verify the convergence with only O(NlogN) complexity by the fast Fourier transform method, where N is the number of the grid points. To the best of our knowledge, this is the first proof for the convergence rate of the V-cycle multigrid finite element method with τ → 0. Copyright © 2017, The Authors. All rights reserved.

关键词： Fast Fourier transforms

Energy efficiency analysis of heterogeneous platforms: Early experiences 7

学校读者我要写书评

暂无评论

Energy efficiency analysis of heterogeneous platforms: Early...

7th International Green and Sustainable Computing Conference, IGSC 2016

作者： Li, Youhuizi Shi, Weisong Jiang, Congfeng Zhang, Jilin Wan, Jian Key Laboratory of Complex Systems Modeling and Simulation Hangzhou Dianzi University China Mobile and Internet Systems Laboratory Wayne State University United States School of Information and Electronic Engineering Zhejiang University of Science and Technology China

ISBN: (纸本)9781509051175

Heterogeneous multi-core platforms, e.g., ARM's ***, are a promising trend to improve the performance and energy efficiency of future mobile systems. However, the immediate benefits and the challenges to take advantage of the heterogeneity are still not clear. In this paper, we present our early experiences about the energy efficiency of the two *** heterogeneous platforms: ODROID XU+E and ODROID XU3. We quantified compared them with homogeneous platforms through multiple benchmarks which include popular mobile applications and high-performance parallel benchmarks. Besides, we analyzed the scheduling impact on the energy consumption of the heterogeneous platforms and the migration cost is also discussed. Based on the results, several insights, such as fine-granularity power control and thread level parallelism, related to hardware, application and system design are derived. © 2016 IEEE.

关键词： Energy utilization

New self-calibration schemes for accelerometers in platform INS

学校读者我要写书评

暂无评论

Journal of systems Engineering and Electronics 2015年第5期26卷 1032-1042页

作者： Hong Cai Anliang Li Yuan Cao College of Aerospace Science and Engineering National University of Defence Technology Science and Technology on Complex Land Systems Simulation Laboratory

To ensure success of precise navigation, it is necessary to carry out in-field calibration for the accelerometers in platform inertial navigation system(PINS) before a mission is *** continuous self-calibration methods are not fit for fast calibration of accelerometers because the platform misalignments have to be estimated precisely and the nonlinear coupling terms will affect accuracy. The multi-position methods with a "shape of motion" algorithm also have some existing disadvantages: High precision calibration results cannot be obtained when the accelerometer’s output data are used directly and it is difficult to optimize the calibration scheme. Focusing on this field, this paper proposes new fast self-calibration methods for the accelerometers of PINS. A data compression filter is employed to improve the accuracy of parameter estimation because it is impossible to obtain non-biased estimation for accelerometer parameters when using the "shape of motion" algorithm. Besides, continuous calibration schemes are designed and optimized by the genetic algorithm(GA) to improve the observability of parameters. simulations prove that the proposed methods can estimate the accelerometer parameter more precisely than traditional continuous methods and multi-position methods, and they are more practical to deal with urgent situations than multi-position methods.

关键词： self-calibration accelerometers data compression genetic algorithm

Grand-canonical Monte-Carlo simulation of solutions of salt mixtures: theory and implementation

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Nguyen, Toan T. VNU Key Laboratory"Multiscale Simulation of Complex Systems" Faculty of Physics VNU University of Science Vietnam National University 334 Nguyen Trai Street Thanh Xuan Hanoi School of Physics Georgia Institute of Technology 837 State Street AtlantaGA30332-0430 United States

A Grand-canonical Monte-Carlo simulation method extended to simulate a mixture of salts is presented. Due to charge neutrality requirement of electrolyte solutions, ions must be added to or removed from the system in groups. This leads to some complications compared to regular Grand Canonical simulation. Here, a recipe for simulation of electrolyte solution of salt mixture is presented. It is then implemented to simulate solution of 1:1, 2:1 and 2:2 salts or their mixtures at different concentrations using the primitive ion model. The osmotic pressures of the electrolyte solutions are calculated and shown to depend linearly on the salt concentrations within the concentration range simulated. We also show that at the same concentration of divalent anions, the presence of divalent cations make it easier to insert monovalent cations into the system. This can explain some quantitative differences observed in experiments of the MgCl2 salt mixture and MgSO4 salt mixture. Copyright © 2017, The Authors. All rights reserved.

关键词： Magnesium compounds

Beyond bilinear: Generalized multimodal factorized high-order pooling for visual question answering

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Yu, Zhou Yu, Jun Xiang, Chenchao Fan, Jianping Tao, Dacheng Key Laboratory of Complex Systems Modeling and Simulation School of Computer Science and Technology Hangzhou Dianzi University China Department of Computer Science University of North Carolina Charlotte United States UBTECH Sydney Artificial Intelligence Centre School of Information Technologies Faculty of Engineering and Information Technologies University of Sydney DarlingtonNSW2008 Australia

Visual question answering (VQA) is challenging because it requires a simultaneous understanding of both visual content of images and textual content of questions. To support the VQA task, we need to find good solutions for the following three issues: 1) fine-grained feature representations for both the image and the question;2) multi-modal feature fusion that is able to capture the complex interactions between multi-modal features;3) automatic answer prediction that is able to consider the complex correlations between multiple diverse answers for the same question. For fine-grained image and question representations, a 'co-attention' mechanism is developed by using a deep neural network architecture to jointly learn the attentions for both the image and the question, which can allow us to reduce the irrelevant features effectively and obtain more discriminative features for image and question representations. For multi-modal feature fusion, a generalized Multi-modal Factorized High-order pooling approach (MFH) is developed to achieve more effective fusion of multi-modal features by exploiting their correlations sufficiently, which can further result in superior VQA performance as compared with the state-of-the-art approaches. For answer prediction, the KL (Kullback-Leibler) divergence is used as the loss function to achieve precise characterization of the complex correlations between multiple diverse answers with same or similar meaning, which can allow us to achieve faster convergence rate and obtain slightly better accuracy on answer prediction. A deep neural network architecture is designed to integrate all these aforementioned modules into a unified model for achieving superior VQA performance. With an ensemble of our MFH models, we achieve the state-of-the-art performance on the large-scale VQA datasets and win the runner-up in VQA Challenge 2017. Copyright © 2017, The Authors. All rights reserved.

关键词： Deep neural networks

Quasi-two-body decays B → ηc(1S, 2S) [ρ(770), ρ(1450), ρ(1700) →] ππ in the perturbative QCD approach

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Li, Ya Ma, Ai-Jun Rui, Zhou Xiao, Zhen-Jun Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing Jiangsu210023 China College of Sciences North China University of Science and Technology Tangshan063009 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing Jiangsu210023 China

In this paper, we calculated the branching ratios of the quasi-two-body decays B → ηc(1S, 2S) [ρ(770), ρ(1450), ρ(1700) →]ππ by employing the perturbative QCD (PQCD) approach. The contributions from the P -wave resonances ρ(770), ρ(1450) and ρ(1700) were taken into account. The two-pion distribution amplitude ΦPππ is parameterized by the vector current time-like form factor Fπ to study the considered decay modes. We found that (a) the PQCD predictions for the branching ratios of the considered quasi-two-body decays are in the order of 10−7 ∼ 10−6, while the two-body decay rates B(B → ηc(1S, 2S)(ρ(1450), ρ(1700))) are extracted from those for the corresponding quasi-two-body decays;(b) the whole pattern of the pion form factor-squared |Fπ|2 measured by the BABAR Collaboration could be understood based on our theoretical results;(c) the general expectation based on the similarity between B → ηcππ and B → J/ψππ decays are confirmed: R2(ηc) ≈ 0.45 is consistent with the measured R2(J/ψ) ≈ 0.56 ± 0.09 within errors;and (d) new ratios R3(ηc(1S)) and R4(ηc(2S)) among the branching ratios of the considered decay modes are defined and could be tested by future experiments. Copyright © 2017, The Authors. All rights reserved.

关键词： Hadrons

LPI radar signal detection based on radial integration of Choi-Williams time-frequency image

学校读者我要写书评

暂无评论

Journal of systems science & complexity 2015年第5期28卷 973-981页

作者： Yongjian Liu Peng Xiao Hongchao Wu Weihua Xiao Science and Technology on Complex Aviation Systems Simulation Laboratory Aviation University of Air Force

This paper mainly revolves the time-frequency image of low probability of intercept(LPI) radar signals and carries out research work on image features selection and extraction and recognition. Since Choi-Williams distribution(CWD) uses the exponential kernel of bilinear generalized class of time-frequency distribution, it has an excellent time-frequency aggregation. And it is suitable for detecting LPI radar signals in a low signal-to-noise ratio(SNR) condition. A radial integration method based on the integral rotating factor is proposed to detect LPI radar signals when the signals' time-frequency image is obtained. First, the digital image processing method is used to preprocess the LPI radar signals' time-frequency images after CWD transformation; then, the radial integration method based on the integral rotating factor is used to detect LPI radar signals in the binary images. The analytic results of real data show that the method has a good performance on detecting LPI radar signals in a low SNR condition. Additionally,the method is simple and takes less logic resources and has the potential of real-time detection of LPI radar signals.

关键词： low probability of intercept （LPI） integral rotating fac-tor signal detection image processing

A system-of-systems architecture-driven modeling method for combat system effectiveness simulation 2

学校读者我要写书评

暂无评论

A system-of-systems architecture-driven modeling method for ...

2nd Annual IEEE International Symposium on systems Engineering, ISSE 2016

作者： Li, Xiaobo Wang, Weiping Shu, Zhe Zhu, Ning He, Hua Liao, Tianjun College of Information Systems and Management National University of Defense Technology Changsha Hunan410073 China Department of Mathematics and Computer Science University of Antwerp Antwerp2020 Belgium State Key Laboratory of Complex System Simulation Beijing Institute of Systems Engineering Beijing China

ISBN: (纸本)9781509007936

Under the background of system-of-systems (SoS) counterwork, it is more apparent that the simulation modeling of the equipment should be domain-specific, formal, automatic and composable. Current equipment effectiveness simulation modeling approaches are mainly based on the methods and techniques from the modeling and simulation (M&S) community and software engineering community, and they are not capable to satisfy these four requirements systematically. Thus the systems engineering architecture model and domain knowledge should be used to support effectiveness simulation modeling more effectively. In this research, we propose an architecture-driven modeling method which conforms to the principle of architecture-driven development, uses ontology techniques to build equipment SoS architecture model and sub-domain ontology. This method performs architecture driven simulation modeling to realize the transformation from architecture models to simulation model frameworks;employs ontological metamodeling to design domain-specific modeling languages (DSML) based on the comprehensive usage of architecture models, sub-domain ontologies and M&S formalisms;integrates domain-specific simulation models from various domains using the model framework, and supports the composable development of simulation applications. © 2016 IEEE.

关键词： System of systems

Virtual Page Behavior Based Page Management Policy for Hybrid Main Memory in Cloud Computing 12

学校读者我要写书评

暂无评论

Virtual Page Behavior Based Page Management Policy for Hybri...

12th International Conference on Mobile Ad-Hoc and Sensor Networks, MSN 2016

作者： Huang, Jie Zhang, Xuan Han, Guangjie Jia, Gangyong Liyou, Huizi Wan, Jian Department of Computer Science and Technology Hangzhou Dianzi University Hangzhou310018 China Key Laboratory of Complex Systems Modeling and Simulation Ministry of Education Hangzhou310018 China Department of Information and Communication Systems Hohai University Changzhou213022 China School of Information and Electronic Engineering Zhejiang University of Science and Technology Hangzhou310023 China

ISBN: (纸本)9781509056965

A new generation memory, Non-Volatile Memory (NVM), such as Phase-Change Memory (PCM), has been adopted together with DRAM in the main memory to form the hybrid main memory for low energy consumption and high capacity. The biggest challenge of hybrid memory is how to decrease the average memory access cost for the higher cost of NVM's read/write operation. Currently, most researches are based on migration. However, the page migration itself is a high cost operation. And the migration based policy produces many migration operations, which induces high cost in memory access. Therefore, in order to decrease the cost, we present a virtual page behavior based page management policy (VBPM) in this paper. According to the virtual pages' behavior, we allocate virtual pages into DRAM or PCM physical pages correspondingly. The whole process is migration independent. The experimental results show our VBPM decreases the average memory access time by 24%, moreover, VBPM improves real-time performance in critical path. © 2016 IEEE.

关键词： Phase change memory