Common-image gathers are an important output of prestack depth migration. They provide information needed for velocity model building and amplitude and phase information for subsurface attribute interpretation. Conventionally, common-image gathers are computed using Kirchhoff migration on commonoffset/azimuth data volumes. When geologic structures are complex and strong contrasts exist in the velocity model, the complicated wave behaviors will create migration artifacts in the image gathers. As long as the gather output traces are indexed by any surface attribute, such as source location, receiver location, or surface plane-wave direction, they suffer from the migration artifacts caused by multiple raypaths. These problems have been addressed in a significant amount of work, resulting in common-image gathers computed in the reflection angle domain, whose traces are indexed by the subsurface reflection angle and/or the subsurface azimuth angle.Most of these efforts have concentrated on Kirchhoff and oneway wave-equation migration methods. For reverse time migration, subsurface angle gathers can be produced using the same approach as that used for one-way wave-equation migration. However, these approaches need to be revisited when producing high-quality subsurface angle gathers in three dimensions (reflection angle/azimuth angle), especially for wide-azimuth data. We have developed a method for obtaining 3D subsurface reflection angle/azimuth angle common-image gathers specifically for the amplitude-preserved reverse time migration. The method builds image gathers with a highdimensional convolution of wavefields in the wavenumber domain. We have found a windowed antileakage Fourier transform method that leads to an efficient and practical implementation. This approach has generated high-resolution angle-domain gathers on synthetic 2.5D data and 3D wideazimuth real data.

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Full three-dimensional time-dependent quantum wave-pack calculations have been carried out for the F+HCl and F+DCl reactions on a many-body expansion of the ground 2A′HClF potential energy surface. The calculated energy-dependence of reaction probability exhibits oscillating structure in the F+HCl reaction but not in the F+DCl system. The effects of initial state excitation on the total reaction probabilities as a function of collision energy are investigated for reactions from various initial vibrational and rotational states of HCl and DCl. Our results show that reagent vibrational and/or rotational excitation can generally lead to an increase in reaction probability at low collision energy and a slight decrease at relatively high collision energy. Thermal rate constants for the title reactions are calculated and they are in generally good agreement with experimental measurement. Investigation of steric effects for the reactions indicates that the H (or D) side of HCl (or DCl) molecule is only slightly favored for reactive attack and reaction proceeds from almost all attack angles. The present results indicate that the H/D kinetic isotope effect should not be totally neglected.

Abstract-MapReduce is an emerging programming model for dataintensive application proposed by Google, which has attracted a lot of attention recently. MapReduce borrows ideas from functional programming, where programmer defines Map and Reduce tasks to process large set of distributed data. In this paper we propose an implementation of the MapReduce programming model. We present the architecture of the prototype based on BitDew, a middleware for large scale data management on Desktop Grid. We describe the set of features which makes our approach suitable for large scale and loosely connected Internet Desktop Grid: massive fault tolerance, replica management, barriers-free execution, latency-hiding optimisation as well as distributed result checking. We also present performance evaluation of the prototype both against micro-benchmarks and real MapReduce application. The scalability test shows that we achieve linear speedup on the classic WordCount benchmark. Several scenarios involving lagger hosts and host crashes demonstrate that the prototype is able to cope with an experimental context similar to real-world Internet.

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We present an analytical study on quantum breathers in one-dimensional ferromagnetic XXZ chains with Dzyaloshinsky-Moriya interaction by means of the time-dependent Hartree approximation and the semidiscrete multiple-scale method. The stationary localized single-boson wave functions are obtained and these analytical solutions are checked by numerical simulations. With such stationary localized single-boson wave functions, we construct quantum breather states. Furthermore, the role of the Dzyaloshinsky-Moriya interaction is discussed.

Accurate three-dimensional time-dependent quantum wave packet calculations for the NϩOH reaction on the 3 AЉ potential energy surface ͓Guadagnini, Schatz, and Walch, J. Chem. Phys. 102, 774 ͑1995͔͒ have been carried out. The calculations show for the first time that the initial state-selected reaction probabilities are dominated by resonance structures, and the lifetime of the resonance is generally in the subpicosecond time scale. The calculated reaction cross sections indicate that they are a decreasing function of the translational energy, which is in agreement qualitatively with the quasiclassical trajectory calculations. The rate constants obtained from the quantum mechanical calculations are consistent with the quasiclassical trajectory results and the experimental measurements.

Summary This paper introduces HybridMR, a novel model for the execution of MapReduce (MR) computation on hybrid computing environment. Using this model, high performance cloud resources and heterogeneous desktop personal computers (PCs) in Internet or Intranet can be integrated to form a hybrid computing environment. Thanks to HybridMR, the computation and storage capability of large scale desktop PCs can be fully utilized to process large scale datasets. HybridMR relies on two innovative solutions to enable such large scale data‐intensive computation. The first one is HybridDFS, which is a hybrid distributed file system. HybridDFS features reliable distributed storage that alleviates the volatility of desktop PCs, thanks to fault tolerance and file replication mechanism. The second innovation is a new node priority‐based fair scheduling (NPBFS) algorithm has been developed in HybridMR to achieve both data storage balance and job assignment balance by assigning each node a priority through quantifying CPU speed, memory size, and input and output capacity. In this paper, we describe the HybridMR, HybridDFS, and NPBFS. We report on performance evaluation results, which show that the proposed HybridMR not only achieves reliable MR computation, reduces task response time, and improves the performance of MR, but also reduces the computation cost and achieves a greener computing mode. Copyright © 2015 John Wiley & Sons, Ltd.