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Diagnosing Source Geometrical Complexity of Large Earthquakes

PURE AND APPLIED GEOPHYSICS 2014年第10期171卷 2819-2840页

作者： Rivera, L. Kanamori, H. Univ Strasbourg CNRS Inst Phys Globe Strasbourg Strasbourg France CALTECH Seismol Lab Pasadena CA 91125 USA

We investigated the possible frequency dependence of the moment tensor of large earthquakes by performing W phase inversions using teleseismic data and equally-spaced narrow, overlapping frequency bands. We investigated frequencies from 0.6 to 3.8 mHz. Our focus was on the variation with frequency of the scalar moment, the amount of non-double-couple, and the focal mechanism. We applied this technique to 30 major events in the period 1994-2013 and used the results to detect source complexity. Based on the results, we classed them into three groups according to the variability of the source parameters with frequency: simple, complex and intermediate. Twelve of these events fell into the simple category: Bolivia-1994, Kuril-1994, Sanriku-1994, Antofagasta-1995, Andreanoff-1996, Peru-2001, Sumatra-2004, Sumatra-2005, Tonga-2006, Sumatra-2007, Japan-2011, and the recent Sea of Okhotsk-2013. Seven exhibited significant complexity: Balleny-1998, Sumatra-2000, Indian Ocean-2000, Macquarie Island-2004, Sichuan-2008, and Samoa-2009. The remaining 11 events showed a moderate degree of complexity. Here, we discuss the results of this study in light of independent observations of source complexity, made by various investigators.

关键词： EARTHQUAKES computer algorithms SCALAR field theory RADIATION EIGENVALUES

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Formulation and Simulations of the Conserving Algorithm for Feedback Stabilization on Rigid Body Rotations

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-11页

作者： Pu, Yong-Ren Posbergh, Thomas A. Chang Jung Christian Univ Dept Occupat Safety & Hlth Tainan 71101 Taiwan Univ Minnesota Dept Elect & Comp Engn Minneapolis MN 55455 USA

The problem of stabilization of rigid bodies has received a great deal of attention for many years. People have developed a variety of feedback control laws to meet their design requirements and have formulated various but mostly open loop numerical algorithms for the dynamics of the corresponding closed loop systems. Since the conserved quantities such as energy, momentum, and symmetry play an important role in the dynamics, we investigate the conserved quantities for the closed loop control systems which formally or asymptotically stabilize rigid body rotation and modify the open loop numerical algorithms so that they preserve these important properties. Using several examples, the authors first use the open loop algorithm to simulate the tumbling rigid body actions and then use the resulting closed loop one to stabilize them.

关键词： computer simulation computer algorithms FEEDBACK control systems RIGID bodies (Mechanics) CLOSED loop systems ENERGY conservation

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Visual wafer dies counting using geometrical characteristics

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IET IMAGE PROCESSING 2014年第5期8卷 280-288页

作者： Xu, Shaoqiu Cheng, Zhihang Gao, Yang Pan, Qing Guangdong Univ Technol Fac Informat Engn Guangzhou 510006 Guangdong Peoples R China

This study presents a computer vision-based wafer dies counting algorithm. It utilises the single model and multi-model RANSAC (Random Sample Consensus) algorithms to detect the circular contour of a wafer and its dicing lanes, respectively. Statistical analysis is performed to extract the characteristics of layout so that missed dicing lanes can be supplemented. The number of integral dies is counted after segmenting individual dies based on the complete layout information. The experimental results show that the proposed algorithm has high counting accuracy and good computational efficiency.

关键词： GEOMETRIC analysis computer vision computer algorithms SAMPLING (Statistics) SEGMENTATION (Image processing)

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A divide-conquer-recombine algorithmic paradigm for large spatiotemporal quantum molecular dynamics simulations

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JOURNAL OF CHEMICAL PHYSICS 2014年第18期140卷 18A529-18A529页

作者： Shimojo, Fuyuki Hattori, Shinnosuke Kalia, Rajiv K. Kunaseth, Manaschai Mou, Weiwei Nakano, Aiichiro Nomura, Ken-ichi Ohmura, Satoshi Rajak, Pankaj Shimamura, Kohei Vashishta, Priya Univ So Calif Dept Comp Sci Dept Phys & Astron Los Angeles CA 90089 USA Univ So Calif Dept Chem Engn & Mat Sci Los Angeles CA 90089 USA Kumamoto Univ Dept Phys Kumamoto 8608555 Japan Natl Nanotechnol Ctr Pathum Thani 12120 Thailand Kyoto Univ Dept Phys Kyoto 6068502 Japan Kyushu Univ Dept Appl Quantum Phys & Nucl Engn Fukuoka 8190395 Japan

We introduce an extension of the divide-and-conquer (DC) algorithmic paradigm called divide-conquer-recombine (DCR) to perform large quantum molecular dynamics (QMD) simulations on massively parallel supercomputers, in which interatomic forces are computed quantum mechanically in the framework of density functional theory (DFT). In DCR, the DC phase constructs globally informed, overlapping local-domain solutions, which in the recombine phase are synthesized into a global solution encompassing large spatiotemporal scales. For the DC phase, we design a lean divide-and-conquer (LDC) DFT algorithm, which significantly reduces the prefactor of the O(N) computational cost for N electrons by applying a density-adaptive boundary condition at the peripheries of the DC domains. Our globally scalable and locally efficient solver is based on a hybrid real-reciprocal space approach that combines: (1) a highly scalable real-space multigrid to represent the global charge density;and (2) a numerically efficient plane-wave basis for local electronic wave functions and charge density within each domain. Hybrid space-band decomposition is used to implement the LDC-DFT algorithm on parallel computers. A benchmark test on an IBM Blue Gene/Q computer exhibits an isogranular parallel efficiency of 0.984 on 786 432 cores for a 50.3 x 10(6)-atom SiC system. As a test of production runs, LDC-DFT-based QMD simulation involving 16 661 atoms is performed on the Blue Gene/Q to study on-demand production of hydrogen gas from water using LiAl alloy particles. As an example of the recombine phase, LDC-DFT electronic structures are used as a basis set to describe global photoexcitation dynamics with nonadiabatic QMD (NAQMD) and kinetic Monte Carlo (KMC) methods. The NAQMD simulations are based on the linear response time-dependent density functional theory to describe electronic excited states and a surface-hopping approach to describe transitions between the excited states. A series of techniques

关键词： MOLECULAR dynamics RESEARCH SUPERcomputerS DENSITY functional theory PARALLEL computers computer algorithms MONTE Carlo method LINEAR systems

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A Fast Iterative Pursuit Algorithm in Robust Face Recognition Based on Sparse Representation

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-11页

作者： Jian, Zhao Huang Luxi Jian, Jia Yu, Xie Northwest Univ Sch Informat Sci & Technol Xian 710069 Peoples R China Northwest Univ Dept Math Xian 710069 Peoples R China

A relatively fast pursuit algorithm in face recognition is proposed, compared to existing pursuit algorithms. More stopping rules have been put forward to solve the problem of slow response of OMP, which can fully develop the superiority of pursuit algorithm - avoiding to process useless information in the training dictionary. For the test samples that are affected by partial occlusion, corruption, and facial disguise, recognition rates of most algorithms fall rapidly. The robust version of this algorithm can identify these samples automatically and process them accordingly. The recognition rates on ORL database, Yale database, and FERET database are 95.5%, 93.87%, and 92.29%, respectively. The recognition performance under various levels of occlusion and corruption is also experimentally proved to be significantly enhanced.

关键词： ITERATIVE methods (Mathematics) ROBUST control HUMAN face recognition (computer science) SPARSE approximations computer algorithms PROBLEM solving

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In-Orbit Tracking of Resident Space Objects: A Comparison of Monocular and Stereoscopic Vision

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IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS 2014年第1期50卷 676-688页

作者： Segal, Shai Gurfil, Pini Shahid, Kamran Technion Israel Inst Technol IL-32000 Haifa Israel Technion Israel Inst Technol Dept Aerosp Engn IL-32000 Haifa Israel

This paper develops new methods for vision-based satellite attitude control aimed at space-based optical tracking of resident space objects (RSOs). An Earth-orbiting chaser satellite equipped with either one or two body-fixed cameras can successfully track an RSO provided that the target is kept within the camera field of view. Because the cameras are body fixed, the attitude of the satellite needs to be controlled to maintain target lock. Novel vision-based control algorithms are developed to align the chaser camera's optical axis with the chaser-target line of sight. Two control architectures are presented for the cases of monocular and stereoscopic vision. In the case of the monocular architecture, relative chaser-target acceleration information is not available. Moreover, in both cases unknown perturbations can impair the tracking performance. To increase the tracking algorithm's robustness to these effects, a variable structure attitude control technique is employed. The stability of the developed control laws are substantiated based on Lyapunov's direct method and demonstrated using Monte Carlo simulations. The results clearly show that using stereoscopic vision yields faster target tracking, increased robustness to noise and field-of-view limits, and reduced fuel consumption compared with monocular vision-based attitude tracking.

关键词： Noise robustness Residency SATELLITE ATTITUDE CONTROL new methods field camera CHASERS computer algorithms Depth Perception Cameras Fuel consumption satellites

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Reconstruction of opaque inclusions in objects with high refractive index

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PROGRAMMING AND computer SOFTWARE 2014年第4期40卷 185-192页

作者： Lebedev, A. S. Gaganov, V. A. Ignatenko, A. V. Moscow MV Lomonosov State Univ Moscow 119991 Russia

The problem of reconstruction of inclusions in rough diamonds occupies an important place in the entire technological process of extraction and cutting precious stones. Inclusions are foreign objects that are naturally formed in raw stock during the formation of diamond (see Fig. 1). The algorithm proposed in the present paper performs a full reconstruction of three-dimensional models of inclusions from photo images. Three-dimensional models of inclusions are based on a voxel representation. The algorithm performs the coloring of voxels and the segmentation of a voxel grid and constructs polygonal models of inclusions. Experiments carried out on real and synthetic data show that the algorithm can reconstruct three-dimensional models of medium- and large-size inclusions, which may serve as a first approximation for the methods of refinement of the shape of inclusions.

关键词： DATA extraction REFRACTIVE index ELECTRONIC data processing -- Research computer algorithms computer programming

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Cloud-clearing techniques over land for land-surface temperature retrieval from the Advanced Along-Track Scanning Radiometer

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2014年第10期35卷 3594-3615页

作者： Bulgin, C. E. Sembhi, H. Ghent, D. Remedios, J. J. Merchant, C. J. Univ Edinburgh Sch Geosci Edinburgh Midlothian Scotland Univ Leicester Space Res Ctr Leicester Leics England Univ Reading Dept Meteorol Reading Berks England

We present five new cloud detection algorithms over land based on dynamic threshold or Bayesian techniques, applicable to the Advanced Along-Track Scanning Radiometer (AATSR) instrument and compare these to the standard threshold-based SADIST cloud detection scheme. We use a manually classified dataset as a reference to assess algorithm performance and quantify the impact of each cloud detection scheme on land-surface temperature (LST) retrieval. The use of probabilistic Bayesian cloud detection methods improves algorithm true skill scores by 8-9% over SADIST (maximum score of 77.93% compared with 69.27%). We present an assessment of the impact of imperfect cloud masking, in relation to the reference cloud mask, on the retrieved AATSR LST imposing a 2K tolerance over a 3x3 pixel domain. We find an increase of 5-7% in the observations falling within this tolerance when using Bayesian methods (maximum of 92.02% compared with 85.69%). We also demonstrate that the use of dynamic thresholds in the tests employed by SADIST can significantly improve performance, applicable to cloud-test data to be provided by the Sea and Land Surface Temperature Radiometer (SLSTR) due to be launched on the Sentinel 3 mission (estimated 2014).

关键词： LAND surface temperature RADIOMETERS BAYESIAN analysis OCEAN temperature CLOUDS RESEARCH computer algorithms

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A Sweep-Line Method for Buchi Automata-based Model Checking

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FUNDAMENTA INFORMATICAE 2014年第1期131卷 27-53页

作者： Evangelista, Sami Kristensen, Lars Michael Univ Paris 13 Sorbonne Paris Cite LIPN CNRSUMR 7030 F-93430 Villetaneuse France Bergen Univ Coll Dept Comp Math & Phys Bergen Norway

The sweep-line method allows explicit state model checkers to delete states from memory on-the-fly during state space exploration, thereby lowering the memory demands of the verification procedure. The sweep-line method is based on a least-progress-first search order that prohibits the immediate use of standard on-the-fly Buchi automata-based model checking algorithms that rely on a depth-first search order in the search for an acceptance cycle. This paper proposes and experimentally evaluates an algorithm for Buchi automata-based model checking compatible with the search order and deletion of states prescribed by the sweep-line method.

关键词： MACHINE theory computer storage devices computer systems -- Verification computer algorithms SEARCH engines

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An Improved Task Scheduling Algorithm for Intelligent Control in Tiny Mechanical System

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-8页

作者： Wang, Jialiang Zhao, Hai Bi, Yuanguo Chen, Xingchi Zeng, Ruofan Wang, Yu Northeastern Univ Coll Informat Sci & Engn Shenyang 110819 Peoples R China

Wireless sensor network (WSN) has been already widely used in many fields in terms of industry, agriculture, and military, and so forth. The basic composition is WSN nodes that are capable of performing processing, gathering information, and communicating with other connected nodes in the network. The main components of a WSN node are microcontroller, transceiver, and some sensors. Undoubtedly, it also can be added with some actuators to form a tiny mechanical system. Under this case, the existence of task preemption while executing operating system will not only cost more energy for WSN nodes themselves, but also bring unacceptable system states caused by vibrations. However for these nodes, task I/O delays are inevitable due to the existence of task preemption, which will bring extra overhead for the whole system, and even bring unacceptable system states caused by vibrations. This paper mainly considers the earliest deadline first (EDF) task preemption algorithm executed in WSN OS and proposes an improved task preemption algorithm so as to lower the preemption overhead and I/O delay and then improve the system performance. The experimental results show that the improved task preemption algorithm can reduce the I/O delay effectively, so the real-time processing ability of the system is enhanced.

关键词： WIRELESS sensor networks computer algorithms TASK performance SCHEDULING INTELLIGENT control systems

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