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A numerical algorithm for calculating microbial survival curves during thermal processing

FOOD RESEARCH INTERNATIONAL 2007年第1期40卷 203-208页

作者： Chen, Guibing Campanella, Osvaldo H. Corvalan, Carlos M. Purdue Univ Dept Agr & Biol Engn W Lafayette IN 47907 USA Purdue Univ Dept Food Sci W Lafayette IN 47907 USA

Assuming that the targeted microorganism's isothermal survival curves follow the Weibullian pattern, which describes a large number of microbial isothermal survival curves, a simple numerical algorithm was developed to calculate the momentary survival ratio during non-isothermal thermal processes. The algorithm is based on a mathematical expression derived from a non-isothermal survival rate model proposed in the literature. Simulations indicated that the proposed algorithm generated the same results as those obtained from other non-isothermal models found in the literature. However, compared to the published models, the proposed algorithm has two advantages. One is that the calculation speed is very fast because only simple algebraic operations are involved, and the other is that it can be programmed very easily in different computer languages and spreadsheets. In addition, the algorithm provides an effective way to estimate changes of microbial survival ratio with time from product temperatures that are either directly measured during thermal processing or predicted by proper heat transfer models. Thus, the algorithm can also be easily incorporated into control systems of commercial thermal process equipment. (c) 2006 Elsevier Ltd. All rights reserved.

关键词： numerical algorithm microbial survival curves thermal processing Weibullian model

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Theoretical modeling and experimental verification for structural response of NOPD based on endochronic theory

Theoretical modeling and experimental verification for struc...

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1st International Conference on Mechanical Engineering

作者： Wang Wei Li Yuyan Chinese Acad Sci Space Opt Lab Xian Inst Opt & Precis Mech Xian 710119 Peoples R China Xian Technol univ Dept Mech & Elect Engn Xian 710032 Peoples R China

ISBN: (纸本)9783037850770

Non-obstructive particle damping (NOPD) is a new composite damping technology based on traditional partical damping and impacting damping, and it has good vibration-reduced results. Through studying thermodynamics constraint condition for non-inverse variation of inner tissue structure of the material, the endochronic theory obtained variation regularity of inner variable, further gave out evolution path of specific non-inverse thermodynamics variable under specific condition, and thus the constitutive relationship of the material was obtained. Based on endochronic theory, an incremental form of the endochronic constitutive relationship of discrete particle was derived, and then penalty element was introduced to solve the connection problem between structure and discrete particle, lastly finite element dynamics equation of NOPD composite structure was constructed. Based on the model of NOPD composite structure, simulation and experiment for response of NOPD free beam were made. It indicated that applying endochronic theory to analyze the response of NOPD is rational, which supplied an effective method for engineering application of NOPD.

关键词： Non-obstructive particle damping Endochronic theory Structural response Vibration-reduced numerical algorithm

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Fuzzy Optimal Control Problem with Non-linear Functional

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FUZZY INFORMATION AND ENGINEERING 2011年第3期3卷 311-320页

作者： Niftiyev, A. A. Zeynalov, C. I. Poormanuchehri, M. Baku State Univ Inst Appl Math Baku Azerbaijan Naxchivan State Univ Nakhchivan Azerbaijan

In this paper, we introduce a new space of fuzzy numbers equipped with a scalar product defined in this space. The notion of a derivative of a fuzzy function in this space is defined. By employing these notions, an optimal control problem with non-linear functional is formulated and an optimality condition is obtained in the form of maximum principle. Using this result, the numerical algorithm is offered for the solution of such problems.

关键词： Space of fuzzy numbers Fuzzy differential equation Optimality condition Maximum principle numerical algorithm

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numerical Construction of Nash and Stackelberg Solutions in a Two-Player Linear Non-Zero-Sum Positional Differential Game

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PROCEEDINGS OF THE STEKLOV INSTITUTE OF MATHEMATICS 2010年第1-Sup期269卷 S147-S161页

作者： Kleimenov, A. F. Kuvshinov, D. R. Osipov, S. I. Russian Acad Sci Inst Math & Mech Ural Div Ul S Kovalevskoi 16 Ekaterinburg 620990 Russia Ural State Univ Ekaterinburg 620083 Russia

numerical methods are proposed for constructing Nash and Stackelberg solutions in a two-player linear non-zero-sum positional differential game with terminal cost functionals and geometric constraints on the players' controls. The formalization of the players' strategies and of the motions generated by them is based on the formalization and results from the theory of positional zero-sum differential games developed by N.N. Krasovskii and his school. It is assumed that the game is reduced to a planar game and the constraints on the players' controls are given in the form of convex polygons. The problem of finding solutions of the game may be reduced to solving nonstandard optimal control problems. Several computational geometry algorithms are used to construct approximate trajectories in these problems, in particular, algorithms for constructing the convex hull as well as the union, intersection, and algebraic sum of polygons.

关键词： non-zero-sum positional differential game Nash solution Stackelberg solution numerical algorithm

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A Taylor series approach to the numerical analysis of the M/D/1/N queue

A Taylor series approach to the numerical analysis of the M/...

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International Conference on Computational Science (ICCS)

作者： Abbas, Karim Heidergott, Bernd Aissani, Djamil Vrije Univ Amsterdam Amsterdam Netherlands Univ Bejaia LAMOS Bejaia Algeria

This paper presents a functional approximation of the M/D/1/N built on a Taylor series approximation. numerical examples are carried out to illustrate the performance of our approach. (C) 2010 Published by Elsevier Ltd.

关键词： Taylor series numerical algorithm queueing

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Spacecraft Magnetic Control Using Dichotomous Coordinate Descent algorithm with Box Constraints

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MODELING IDENTIFICATION AND CONTROL 2010年第4期31卷 123-131页

作者： Schlanbusch, Rune Kristiansen, Raymond Nicklasson, Per Johan Narvik Univ Coll Dept Technol N-8505 Narvik Norway

In this paper we present magnetic control of a spacecraft using the Dichotomous Coordinate Descent (DCD) algorithm with box constraints. What is common for most work on magnetic spacecraft control is the technique for solving for the control variables of the magnetic torquers where a cross product is included which is well known to be singular. The DCD algorithm provides a new scheme which makes it possible to use a general control law and then adapt it to work for magnetic torquers including restrictions in available magnetic moment, instead of designing a specialized controller for the magnetic control problem. A non-linear passivity-based sliding surface controller is derived for a fully actuated spacecraft and is then implemented for magnetic control by utilizing the previous mentioned algorithm. Results from two simulations are provided, the first comparing the results from the DCD algorithm with older results, and the second showing how easily the derived sliding surface controller may be implemented, improving our results.

关键词： Magnetic attitude control numerical algorithm sliding surface control space vehicle control

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New interpolation technique for the CIP method on curvilinear coordinates

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JOURNAL OF COMPUTATIONAL PHYSICS 2010年第16期229卷 5573-5596页

作者： Fujimatsu, Nobuyoshi Suzuki, Kojiro Aoyama Gakuin Univ Dept Mech Sci & Engn Kanagawa 2298558 Japan Univ Tokyo Grad Sch Frontier Sci Dept Adv Energy Chiba 2278561 Japan

We propose a new interpolation technique for the CIP method applied to curvilinear coordinates. The CIP method can hardly maintain third-order accuracy on curvilinear coordinates. The reason for the degeneracy in accuracies has not been discussed in detail. This paper reveals the problems of the CIP method on curvilinear coordinates and presents an improved CIP method to solve the advection equation accurately. The features of the presented method are: (1) the metric computation on the upwind stencil is defined in the same manner as in the advection phase of the CIP method;and (2) gradient values in the physical domain in the computation on the curvilinear coordinates are used. Various test problems show that the improved CIP method has approximate third-order accuracy. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Curvilinear coordinate numerical algorithm Semi-Lagrangian schemes

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Non-parametric Bayesian super-resolution

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IET RADAR SONAR AND NAVIGATION 2010年第4期4卷 639-648页

作者： Lane, R. O. QinetiQ Malvern Technol Ctr Malvern WR14 3PS Worcs England

Super-resolution of signals and images can improve the automatic detection and recognition of objects of interest. However, the uncertainty associated with this process is not often taken into consideration. This is important because the processing of noisy signals can result in spurious estimates of the scene content. This study reviews a variety of super-resolution techniques and presents two non-parametric Bayesian super-resolution algorithms that not only take uncertainty into account, but also retain knowledge about the output uncertainty in the form of a full probability distribution. One of the two Bayesian techniques is based on an analytical calculation re-interpreted as super-resolution, and the other is a novel numerical algorithm. Although the algorithms are presented as stand-alone techniques for image analysis, such Bayesian super-resolution algorithms can increase automatic target recognition performance over standard super-resolution.

关键词： nonparametric Bayesian superresolution image analysis probability automatic object detection object recognition Computer vision and image processing techniques object detection numerical analysis probability distribution Image recognition signal superresolution numerical algorithm automatic object recognition Other numerical methods image superresolution image resolution Other topics in statistics

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Automation of LCF material model parameters' identification

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COMPUTATIONAL MATERIALS SCIENCE 2010年第3期48卷 529-536页

作者： Franulovic, Marina Basan, Robert Kunc, Robert Prebil, Ivan Univ Rijeka Fac Engn HR-51000 Rijeka Croatia Univ Ljubljana Fac Mech Engn SI-1000 Ljubljana Slovenia

Modeling of of material behaviour has significant influence on design and optimization of mechanical structures and consequently calculation of their lifetime. When using complex constitutive material model that describes elastic-plastic behaviour of the cyclically loaded material and takes into account damage occurrence and accumulation, the process of parameter identification from experimental data is very complex and time-consuming. In this paper the damage occurrence and accumulation within the material are described by means of models of Bauschinger effect, kinematic and isotropic hardening (or softening) according to Chaboche material model and mean stress relaxation according to Ohno-Wang material model. Since the material model is highly non-linear, its parameter identification requires complex numerical procedures, carefully chosen algorithms and numerical operators, followed by software solution development. The developed automated system for material model parameter identification is validated by comparing the calculated with experimental response of the material. Its usage can make material behaviour modeling for numerous materials accurate, fast and user-friendly. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Fatigue Constitutive behaviour Elastic-plastic material Finite element numerical algorithm

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Recent Developments in the Pure Streamfunction Formulation of the Navier-Stokes System

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JOURNAL OF SCIENTIFIC COMPUTING 2010年第1-3期45卷 238-258页

作者： Fishelov, D. Ben-Artzi, M. Croisille, J-P. Afeka Tel Aviv Acad Coll Engn IL-69107 Tel Aviv Israel Hebrew Univ Jerusalem Inst Math IL-91904 Jerusalem Israel Univ Paul Verlaine Metz Dept Math LMAM UMR 7122 F-57045 Metz France

In this paper we review fourth-order approximations of the biharmonic operator in one, two and three dimensions. In addition, we describe recent developments on second and fourth order finite difference approximations of the two dimensional Navier-Stokes equations. The schemes are compact both for the biharmonic and the Laplacian operators. For the convective term the fourth order scheme invokes also a sixth order Pade approximation for the first order derivatives, using an approximation suggested by Carpenter-Gottlieb-Abarbanel (J. Comput. Phys. 108:272-295, 1993). We also introduce the derivation of a pure streamfunction formulation for the Navier-Stokes equations in three dimensions.

关键词： Navier-Stokes equations Streamfunction formulation Vorticity numerical algorithm Compact schemes

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