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About Performance and Intellectuality of Supercomputer Modeling

PROGRAMMING AND computer SOFTWARE 2016年第1期42卷 5-16页

作者： Il'in, V. P. Skopin, I. N. Russian Acad Sci Siberian Branch Inst Computat Math & Math Geophys Pr Akad Lavrenteva 6 Novosibirsk 630090 Russia Novosibirsk State Univ Ul Pirogova 2 Novosibirsk 630090 Russia

The concept of supercomputer technologies is traditionally related to mapping algorithms onto the computer architecture, which, taking into account the explosive growth of computational capabilities, implies the necessity for an adequate increase in the performance of algorithms and programs. At the same time, it is well known that the rate of building "computer muscles" far exceeds the rate of increasing the labor productivity of software developers, which becomes a bottleneck of computer evolution. The only way to deal with this problem is to automate the construction of models, algorithms, and programs, which directly implies the revolutionary change in the level of artificial intelligence in supercomputer technologies. In this paper, it is from this standpoint that main computational stages of mathematical modeling of various processes and phenomena are discussed, some aspects of high logical complexity of modern high-performance methods for solving "large" applied problems are pointed out, and some intelligent solutions for various modeling problems are proposed.

关键词： SUPERcomputerS computer science computer architecture computer algorithms ARTIFICIAL intelligence

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Testing of Lagrange multiplier damped least-squares control algorithm for woofer-tweeter adaptive optics

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APPLIED OPTICS 2012年第9期51卷 1198-1208页

作者： Zou, Weiyao Burns, Stephen A. Indiana Univ Sch Optometry Bloomington IN 47405 USA

A Lagrange multiplier-based damped least-squares control algorithm for woofer-tweeter (W-T) dual deformable-mirror (DM) adaptive optics (AO) is tested with a breadboard system. We show that the algorithm can complementarily command the two DMs to correct wavefront aberrations within a single optimization process: the woofer DM correcting the high-stroke, low-order aberrations, and the tweeter DM correcting the low-stroke, high-order aberrations. The optimal damping factor for a DM is found to be the median of the eigenvalue spectrum of the influence matrix of that DM. Wavefront control accuracy is maximized with the optimized control parameters. For the breadboard system, the residual wavefront error can be controlled to the precision of 0.03 mu m in root mean square. The W-T dual-DM AO has applications in both ophthalmology and astronomy. (C) 2012 Optical Society of America

关键词： Optimization Procedure Root mean square ASTRONOMY characteristic spectrum Wavefront aberration absorption of shock computer algorithms Ophthalmology Lagrange AUXILIARY ORIFICES adaptive optics wavefront error algorithms Lagrange multipliers control parameter

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Opposition-Based Animal Migration Optimization

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MATHEMATICAL PROBLEMS IN ENGINEERING 2013年第1期2013卷 1-7页

作者： Cao, Yi Li, Xiangtao Wang, Jianan NE Normal Univ Sch Comp Sci & Informat Technol Changchun 130117 Peoples R China

AMO is a simple and efficient optimization algorithm which is inspired by animal migration behavior. However, as most optimization algorithms, it suffers from premature convergence and often falls into local optima. This paper presents an opposition-based AMO algorithm. It employs opposition-based learning for population initialization and evolution to enlarge the search space, accelerate convergence rate, and improve search ability. A set of well-known benchmark functions is employed for experimental verification, and the results show clearly that opposition-based learning can improve the performance of AMO.

关键词： ANIMAL migration MATHEMATICAL optimization computer algorithms BENCHMARK problems (computer science) LEARNING EVOLUTIONARY algorithms

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Semantic subtyping with an SMT solver

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JOURNAL OF FUNCTIONAL PROGRAMMING 2012年第1期22卷 31-105页

作者： Bierman, Gavin M. Gordon, Andrew D. Hritcu, Catalin Langworthy, David Microsoft Res Cambridge England Univ Penn Philadelphia PA 19104 USA Univ Saarland Philadelphia PA USA Microsoft Corp Redmond WA 98052 USA

We study a first-order functional language with the novel combination of the ideas of refinement type (the subset of a type to satisfy a Boolean expression) and type-test (a Boolean expression testing whether a value belongs to a type). Our core calculus can express a rich variety of typing idioms;for example, intersection, union, negation, singleton, nullable, variant, and algebraic types are all derivable. We formulate a semantics in which expressions denote terms, and types are interpreted as first-order logic formulas. Subtyping is defined as valid implication between the semantics of types. The formulas are interpreted in a specific model that we axiomatize using standard first-order theories. On this basis, we present a novel type-checking algorithm able to eliminate many dynamic tests and to detect many errors statically. The key idea is to rely on a Satisfiability Modulo Theories solver to compute subtyping efficiently. Moreover, using a satisfiability modulo theories solver allows us to show the uniqueness of normal forms for non-deterministic expressions, provide precise counterexamples when type-checking fails, detect empty types, and compute instances of types statically and at run-time.

关键词： FUNCTIONAL programming (computer science) PROGRAMMING languages (Electronic computers) BOOLEAN functions (Mathematics) computer algorithms computer programming INFORMATION theory

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Sharp Separation and Applications to Exact and Parameterized algorithms

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ALGORITHMICA 2012年第3期63卷 692-706页

作者： Fomin, Fedor V. Grandoni, Fabrizio Lokshtanov, Daniel Saurabh, Saket Inst Math Sci Madras 600113 Tamil Nadu India Univ Bergen Dept Informat N-5008 Bergen Norway Univ Roma Tor Vergata Dept Comp Sci Rome Italy

Many divide-and-conquer algorithms employ the fact that the vertex set of a graph of bounded treewidth can be separated in two roughly balanced subsets by removing a small subset of vertices, referred to as a separator. In this paper we prove a trade-off between the size of the separator and the sharpness with which we can fix the size of the two sides of the partition. Our result appears to be a handy and powerful tool for the design of exact and parameterized algorithms for NP-hard problems. We illustrate that by presenting two applications. Our first application is a O(2 (n+o(n)))-time algorithm for the Degree Constrained Spanning Tree problem: find a spanning tree of a graph with the maximum number of nodes satisfying given degree constraints. This problem generalizes some well-studied problems, among them Hamiltonian Path, Full Degree Spanning Tree, Bounded Degree Spanning Tree, and Maximum Internal Spanning Tree. The second application is a parameterized algorithm with running time O(16 (k+o(k))+n (O(1))) for the k-Internal Out-Branching problem: here the goal is to compute an out-branching of a digraph with at least k internal nodes. This is a significant improvement over the best previously known parameterized algorithm for the problem by Cohen et al. (J. Comput. Syst. Sci. 76:650-662, 2010), running in time O(49.4 (k) +n (O(1))).

关键词： computer algorithms SPANNING trees (Graph theory) DIRECTED graphs PARTITIONS (Mathematics) GRAPHIC methods

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Semiautomatic Algorithm for Lymph Node Analysis Corrected for Partial Volume Effects in Combined Positron Emission Tomography-Computed Tomography

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MOLECULAR IMAGING 2010年第6期9卷 319-328页

作者： Bundschuh, Ralph A. Essler, Markus Dinges, Julia Berchtenbreiter, Christian Mariss, Jan Martinez-Moeller, Axel Delso, Gaspar Hohberg, Melanie Nekolla, Stephan G. Schulz, Dominik Ziegler, Sibylle I. Schwaiger, Markus Tech Univ Munich Klinikum Rechts Isar Nukl Med Klin & Poliklin D-81675 Munich Germany Tech Univ Munich Klinikum Rechts Isar Inst Rontgendiagnost D-81675 Munich Germany

Positron emission tomography-computed tomography (PET-CT) is superior compared to stand-alone PET in evaluation of malignancies. Few studies have employed high-resolution structural information to correct PET. We designed a semiautomatic algorithm using CT and PET to obtain a partial volume corrected (PVC) standardized uptake value (SUV) and a combined morphologic and functional parameter (multimodal SUV) for lymph node assessment. Lesions were segmented by a semiautomatic algorithm in CT images. Lesion volume was used for PVC and for calculating the multimodal SUV. The method was applied to 47 lymph nodes (30 patients) characterized as suspicious in F-18-fluorodeoxyglucose-PET-CT. In phantoms, PVC improved significantly the measured uptake of the lesion. In patients, 36 lymph nodes could be segmented without problems;in 11 lesions, a manual interaction was necessary. SUVs before PVC (mean 1.29) increased significantly (p < .0005) after PVC (mean 2.8). If SUV 2.5 was used as a threshold value to distinguish between benign and malignant lesions, 11 of the 47 lesions changed from benign to malignant after the PVC. The mean multimodal SUV was 0.39 mL for the benign lesions and 4.47 mL for the malignant lesions. In this work we presented a method for quantitative analysis of lymph nodes in PET-CT. PVC leads to significant differences in SUV.

关键词： EMISSION tomography LYMPH nodes computer algorithms DIAGNOSTIC imaging PRECANCEROUS conditions DIAGNOSIS COMPARATIVE studies QUANTITATIVE research

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Jazz Harmonic Analysis as Optimal Tonality Segmentation

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computer MUSIC JOURNAL 2011年第2期35卷 49-66页

作者： Choi, Andrew 131 Shawnee Pl SW Calgary AB T2Y 1X1 Canada

The article focuses on the new harmonic analysis algorithm of jazz chord sequences. It says that harmonic analysis algorithm can be solved as a tonality segmentation problem through a dynamic programming algorithm and the outcome of the analysis as understood by jazz musicians resulted from the segmentation and key centers of the segments. It mentions several related areas in studying jazz chord sequences including rule-based harmonic analysis, jazz improvisation systems, and jazz theory.

关键词： HARMONIC analysis (Mathematics) JAZZ SEQUENCES (Musical composition) computer algorithms JAZZ musicians TONALITY DYNAMIC programming CHORDS (Music theory)

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FAST TCP: From theory to experiments

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IEEE NETWORK 2005年第1期19卷 4-11页

作者： Jin, C Wei, D Low, SH Bunn, J Choe, HD Doyle, JC Newman, H Ravot, S Singh, S Paganini, CF Buhrmaster, G Cottrell, L Martin, O Feng, WC CALTECH Networking Lab Pasadena CA 91125 USA MIT Cambridge MA 02139 USA CALTECH Div Phys Math & Astron Pasadena CA 91125 USA CALTECH Tier 2 Ctr Pasadena CA 91125 USA

We describe a variant of TCP, called FAST, that can sustain high throughput and utilization at multigigabits per second over large distances. We present the motivation, review the background theory, summarize key feat... 详细信息

关键词： computer algorithms INTERNET OSCILLATIONS HIGH technology algorithms BROADBAND communication systems

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Elastostatic solutions of a multilayered transversely isotropic piezoelectric system under axisymmetric loading

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ACTA MECHANICA 2017年第1期228卷 107-128页

作者： Liu, Jun Zhang, Pengchong Lin, Gao Li, Chao Lu, Shan Dalian Univ Technol State Key Lab Coastal & Offshore Engn Dalian 116024 Peoples R China Dalian Univ Technol Sch Hydraul Engn Fac Infrastruct Engn Dalian Peoples R China Ocean Engn Joint Res Ctr DUT UWA Dalian Peoples R China Dalian Univ Technol State Key Lab Struct Anal Ind Equipment Dalian 116024 Peoples R China Univ New South Wales Sch Civil & Environm Engn Sydney NSW 2052 Australia

The precise integration algorithm (PIA) and the technique of dual vector formulation are extended to explore the axisymmetric response of multilayered transversely isotropic piezoelectric materials under the action of external forces. The planes of cross-anisotropy are assumed to be parallel to the horizontal surface. The mechanical and electrical loads distributed over a circular area can be applied either on the surface of the layered system or at the interface between neighboring layers with dissimilar materials. By means of the Hankel integral transformation and the approach of dual vector form, the governing partial differential equations are reduced to the standard ordinary differential matrix equation. The PIA is exploited to evaluate the first-order ordinary differential matrix equation in the transformed domain. As the PIA is a highly accurate algorithm, any desired accuracy of axisymmetric piezoelectric solutions can be accomplished. The whole calculation is based on standard matrix algebra, and computational effort can be saved to a great extent. Furthermore, dual vector forms of key equations can facilitate the combination of adjacent strata. Finally, several numerical examples are given to validate the accuracy of the proposed technique and to investigate the influence of loading positions, types of external forces, stratified characters, and weak and thin interlayer on the response of the layered piezoelectric medium.

关键词： PIEZOELECTRIC materials computer algorithms INTEGRAL transforms PARTIAL differential equations NUMERICAL analysis

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Evaluation of Peak Picking Quality in LC-MS Metabolomics Data

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ANALYTICAL CHEMISTRY 2010年第22期82卷 9177-9187页

作者： Brodsky, Leonid Moussaieff, Arieh Shahaf, Nir Aharoni, Asaph Rogachev, Ilana Weizmann Inst Sci Dept Plant Sci IL-76100 Rehovot Israel Univ Haifa Inst Evolut IL-31905 Haifa Israel

The output of LC-MS metabolomics experiments consists of mass-peak intensities identified through a peak-picking/alignment procedure. Besides imperfections in biological samples and instrumentation, data accuracy is highly dependent on the applied algorithms and their parameters. Consequently, quality control (QC) is essential for further data analysis. Here, we present a QC approach that is based on discrepancies between replicate samples. First, the quantile normalization of per-sample log-signal distributions is applied to each group of biologically homogeneous samples. Next, the overall quality of each replicate group is characterized by the Z-transformed correlation coefficients between samples. This general QC allows a tuning of the procedure's parameters which minimizes the inter-replicate discrepancies in the generated output. Subsequently, an in-depth QC measure detects local neighborhoods on a template of aligned chromatograms that are enriched by divergences between intensity profiles of replicate samples. These neighborhoods are determined through a segmentation algorithm. The retention time (RT)-m/z positions of the neighborhoods with local divergences are indicative of either: incorrect alignment of chromatographic features, technical problems in the chromatograms, or to a true biological discrepancy between replicates for particular metabolites. We expect this method to aid in the accurate analysis of metabolomics data and in the development of new peak-picking/alignment procedures.

关键词： METABOLITES LIQUID chromatography computer algorithms QUALITY control DATA analysis C++ (computer program language) SOFTWARE

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