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Optimal control for a discrete time influenza model

2nd Colombian Congress on Computational Biology and Bioinformatics, CCBCOL 2013

作者： Parra, Paula Andrea Gonzalez Ceberio, Martine Lee, Sunmi Castillo-Chavez, Carlos Universidad Autónoma de Occidente Departamento de Matematicas Cali Colombia The University of Texas at El Paso Computer Science Department El Paso TX 79968-0514 United States Kyung Hee University Department of Applied Mathematics Yongin 446-701 Korea Republic of Arizona State University Mathematical Computational and Modeling Sciences Center Tempe AZ 85287 United States

ISBN: (纸本)9783319015675

We formulated a discrete time model in order to study optimal control strategies for a single influenza outbreak. In our model, we divided the population into four classes: susceptible, infectious, treated, and recovered individuals. The total population was divided into subgroups according to activity or susceptibility levels. The goal was to determine how treatment doses should be distributed in each group in order to reduce the final epidemic size. The case of limited resources is considered by including an isoperimetric constraint. We found that the use of antiviral treatment resulted in reductions in the cumulative number of infected individuals. We proposed to solve the problem by using the primal-dual interior-point method that enforces epidemiological constraints explicitly. © Springer International Publishing Switzerland 2014.

关键词： Optimization

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Island-dynamics model for mound formation: Effect of a step-edge barrier

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Physical Review E 2014年第2期90卷 022404-022404页

作者： Joe Papac Dionisios Margetis Frederic Gibou Christian Ratsch Department of Mathematics University of California Los Angeles California 90095 USA Department of Mathematics and Institute for Physical Science and Technology and Center for Scientific Computation and Mathematical Modeling University of Maryland College Park Maryland 20742 USA Department of Mechanical Engineering and Department of Computer Science and Department of Mathematics University of California Santa Barbara California 93106 USA Department of Mathematics and Institute for Pure and Applied Mathematics University of California Los Angeles California 90095 USA

We formulate and implement a generalized island-dynamics model of epitaxial growth based on the level-set technique to include the effect of an additional energy barrier for the attachment and detachment of atoms at step edges. For this purpose, we invoke a mixed, Robin-type, boundary condition for the flux of adsorbed atoms (adatoms) at each step edge. In addition, we provide an analytic expression for the requisite equilibrium adatom concentration at the island boundary. The only inputs are atomistic kinetic rates. We present a numerical scheme for solving the adatom diffusion equation with such a mixed boundary condition. Our simulation results demonstrate that mounds form when the step-edge barrier is included, and that these mounds steepen as the step-edge barrier increases.

关键词： HEAT equation OPTOELECTRONIC devices EPITAXY CRYSTAL morphology CRYSTAL lattices

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Back-propagating modes in elastic logging-while-drilling collars and their effect on PML stability

Back-propagating modes in elastic logging-while-drilling col...

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作者： Matuszyk, Pawel Jerzy Torres-Verdín, Carlos Department of Petroleum and Geosystems Engineering University of Texas Austin TX 78712 United States Department of Applied Computer Science and Modeling AGH - University of Science and Technology Kraków Poland

The Perfectly Matched Layer (PML) approach is widely used to implement the absorbing boundary conditions for coupled multi-physics wave propagation problems. However, it has been recognized that the solution in the PML absorbing layer can become unstable in the presence of back-propagating modes. This paper analyzes the spectral location of those modes excited by monopole acoustic sources in logging-while-drilling cylindrical tools. To recover the stability of the solution for such a class of problems involving the modeling of elastic cylindrical waveguides, we propose the implementation of artificial attenuation in the waveguide to dampen undesirable modes, thereby making their amplitude negligible in the PML absorbing layer due to the limited numerical accuracy and round-off errors. © 2013 Elsevier Ltd. All rights reserved.

关键词： Acoustic logging

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Physicochemical signatures of nanoparticle-dependent complement activation

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Computational science and Discovery 2014年第1期7卷 015003页

作者： Thomas, Dennis G. Chikkagoudar, Satish Heredia-Langner, Alejandro Tardiff, Mark F. Xu, Zhixiang Hourcade, Dennis E. Pham, Christine T. N. Lanza, Gregory M. Weinberger, Kilian Q. Baker, Nathan A. Knowledge Discovery and Informatics Pacific Northwest National Laboratory RichlandWA99352 United States Applied Statistics and Computational Modeling Group Pacific Northwest National Laboratory RichlandWA99352 United States Department of Computer Science and Engineering Washington University in St. Louis St. LouisMO63130 United States Division of Rheumatology Department of Medicine Washington University School of Medicine St. LouisMO63110 United States Division of Cardiology Department of Medicine Washington University School of Medicine St. LouisMO63110 United States

Nanoparticles are potentially powerful therapeutic tools that have the capacity to target drug payloads and imaging agents. However, some nanoparticles can activate complement, a branch of the innate immune system, and cause adverse side-effects. Recently, we employed an in vitro hemolysis assay to measure the serum complement activity of perfluorocarbon nanoparticles that differed by size, surface charge, and surface chemistry, quantifying the nanoparticle-dependent complement activity using a metric called Residual Hemolytic Activity (RHA). In the present work, we have used a decision tree learning algorithm to derive the rules for estimating nanoparticle-dependent complement response based on the data generated from the hemolytic assay studies. Our results indicate that physicochemical properties of nanoparticles, namely, size, polydispersity index, zeta potential, and mole percentage of the active surface ligand of a nanoparticle, can serve as good descriptors for prediction of nanoparticle-dependent complement activation in the decision tree modeling framework. © 2014 IOP Publishing Ltd.

关键词： Nanoparticles

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DNS and les of excited rectangular jets 8

DNS and les of excited rectangular jets

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8th International Symposium on Turbulence and Shear Flow Phenomena, TSFP 2013

作者： Tyliszczak, Artur Geurts, Bernard J. Department of Mechanical Engineering and Computer Science Institute of Thermal Machinery Czestochowa University of Technology Al. Armii Krajowej 21 Czestochowa42-200 Poland Department of Applied Mathematics Multiscale Modeling and Simulation University of Twente P.O. Box 217 AE Enschede7500 Netherlands

The paper presents results of numerical studies devoted to an active flow control method applied to jet flow and focusses on rectangular jets with aspect ratio Ar = 1, 2 and 3. Square and rectangular jets are more unstable than their circular counterparts, which is expressed by an increased intensity of mixing. It is shown that the application of a suitable excitation (forcing) at the jet nozzle can qualitatively alter the character of the flow, resulting in an increased spreading rate of passive tracer. The excitation is obtained from a superposition of axial and helical forcing terms. We study the mixing in the flow upon varying parameters such as the frequency of the excitations and possible phase shifts between components. The numerical results are obtained applying LES and DNS based on a high-order compact difference code for the incompressible flows.

关键词： Aspect ratio

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Data exploration approach in control of metal forming manufacturing chain. Example of fasteners production

Data exploration approach in control of metal forming manufa...

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14th International Conference on Metal Forming, METAL FORMING 2012

作者： Regulski, Krzysztof Rojek, Gabriel Skóra, Mariusz Kusiak, Jan AGH University of Science and Technology Department of Applied Computer Science and Modeling Al. Mickiewicza 30 30-059 Kraków Poland KOELNER Lańcucka Fabryka Śrub Sp. z o.o. w Lańcucie Poland

ISBN: (纸本)9783514007970

The paper presents the preliminary results of research concerning the data exploration approach in application to the control of production chains. The aim of research is finding the rules that can help the correct setting of process control parameters by using the data exploration techniques. The proposed methodology was validated in the part of a manufacturing chain of fasteners production. The aim was to find relationships between various parameters of heat treatment process, and to determine their influence on the required tensile strength of the final products. Next, the decision rules were elaborated, which can be used in the production control system, allowing achievement of the appropriate quality of final products. Classification trees techniques were used in the presented analysis of the fasteners production. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

关键词： Locks (fasteners)

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Solving satisfiability in fuzzy logics with evolution strategies

Solving satisfiability in fuzzy logics with evolution strate...

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Conference of the North American Fuzzy Information Processing Society - NAFIPS

作者： Tim Brys Yann-Michaël De Hauwere Martine De Cock Ann Nowé Computational Modeling Laboratory Vrije Universiteit Brussel Brussels Belgium Department of Applied Mathematics and Computer Science Universiteit Gent Gent Belgium

Satisfiability in propositional logic is well researched and many approaches to checking and solving exist. In infinite-valued or fuzzy logics, however, there have only recently been attempts at developing methods for solving satisfiability. In this paper, we propose a new incomplete solver, based on a class of continuous optimization algorithms called evolution strategies. We show experimentally that our method is an important contribution to the state of the art in incomplete fuzzy-SAT solvers.

关键词： Sociology Covariance matrix Linear programming Fuzzy logic Benchmark testing Cognition

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Comparison of genetic association strategies in the presence of rare alleles

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BMC proceedings 2011年第9期5 Suppl 9卷 S32页

作者： Jestinah M Mahachie John Tom Cattaert Lizzy De Lobel François Van Lishout Alain Empain Kristel Van Steen Systems and Modeling Unit Montefiore Institute University of Liege Grande Traverse 10 4000 Liège Belgium. Bioinformatics and Modeling GIGA-R University of Liege Avenue de l'Hôpital 1 4000 Liège Belgium. Department of Applied Mathematics and Computer Science Ghent University Krijgslaan 281 S9 9000 Ghent Belgium.

In the quest for the missing heritability of most complex diseases, rare variants have received increased attention. Advances in large-scale sequencing have led to a shift from the common disease/common variant hypothesis to the common disease/rare variant hypothesis or have at least reopened the debate about the relevance and importance of rare variants for gene discoveries. The investigation of modeling and testing approaches to identify significant disease/rare variant associations is in full motion. New methods to better deal with parameter estimation instabilities, convergence problems, or multiple testing corrections in the presence of rare variants or effect modifiers of rare variants are in their infancy. Using a recently developed semiparametric strategy to detect causal variants, we investigate the performance of the model-based multifactor dimensionality reduction (MB-MDR) technique in terms of power and family-wise error rate (FWER) control in the presence of rare variants, using population-based and family-based data (FAM-MDR). We compare family-based results obtained from MB-MDR analyses to screening findings from a quantitative trait Pedigree-based association test (PBAT). Population-based data were further examined using penalized regression models. We restrict attention to all available single-nucleotide polymorphisms on chromosome 4 and consider Q1 as the outcome of interest. The considered family-based methods identified marker C4S4935 in the VEGFC gene with estimated power not exceeding 0.35 (FAM-MDR), when FWER was kept under control. The considered population-based methods gave rise to highly inflated FWERs (up to 90% for PBAT screening).

关键词： Minor Allele Frequency Rare Variant Unrelated Individual Family Data Multiple Testing Corrective Method

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Hybrid knowledge system for optimization of rolling process of DP steels

Hybrid knowledge system for optimization of rolling process ...

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作者： Nadej, Lukasz Rauch, Lukasz Pietrzyk, Maciej Department of Applied Computer Science and Modeling Akademia Gorniczo-Hutnicza Krakow Poland

ISBN: (纸本)0872638685

The development of an efficient easily reconfigurable computer system for simulation of the entire rolling mill facility is presented in the paper. Elements such as furnaces, roughing and finishing mills, descalers, crops thermo-tunnel, roller tables, laminar cooling, coilers are taken into account. As a support to the developed tool the complex knowledge base that facilitates design of rolling technology is also proposed. Detailed description of the implementation technology and its application in numerical calculations and optimization is discussed in the paper. Development of microstructure evolution models is particularly highlighted. Examples of modeling of industrial hot strip rolling process are presented. Development of the rolling technology for modern steel grades like Dual Phase (DP) steels is used as an example.

关键词： Microstructure

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Inside Back Cover: The Reaction Coordinate of a Bacterial GH47 α-Mannosidase: A Combined Quantum Mechanical and Structural Approach (Angew. Chem. Int. Ed. 44/2012)

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Angewandte Chemie International Edition 2012年第44期51卷

作者： Andrew J. Thompson Dr. Jerome Dabin Javier Iglesias-Fernández Dr. Albert Ardèvol Dr. Zoran Dinev Assoc. Prof. Spencer J. Williams Dr. Omprakash Bande Dr. Aloysius Siriwardena Carl Moreland Dr. Ting-Chou Hu David K. Smith Prof. Harry J. Gilbert Prof. Carme Rovira Prof. Gideon J. Davies Department of Chemistry University of York Heslington York YO10 5DD (UK) Computer Simulation & Modeling Laboratory Parc Científic de Barcelona Baldiri Reixac 4 08028 Barcelona (Spain) Institut de Química Teòrica i Computacional (IQTCUB) (Spain) Present address: Departament de Química Orgànica Universitat de Barcelona Martí i Franquès 1 08028 Barcelona (Spain) Present address: Department of Chemistry and Applied Biosciences ETH Zurich USI Campus Via Giuseppe Buffi 13 CH-6900 Lugano (Switzerland) School of Chemistry and Bio21 Molecular Science and Biotechnology Institute University of Melbourne Parkville (Australia) Université de Picardie Jules Vernes Laboratoire des Glucides (CNRS-FRE 3617) 33 Rue Saint Leu 80039 Amiens (France) Institute for Cell and Molecular Biosciences The Medical School Newcastle University Framlington Place Newcastle upon Tyne NE2 4HH (UK) Institució Catalana de Recerca i Estudis Avançats (ICREA) Passeig Lluís Companys 23 08020 Barcelona (Spain) Carme Rovira Computer Simulation & Modeling Laboratory Parc Científic de Barcelona Baldiri Reixac 4 08028 Barcelona (Spain) Gideon J. Davies Department of Chemistry University of York Heslington York YO10 5DD (UK)

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