The mechanical behaviour of a superplastic material is often modelled by the power law relationship between the equivalent flow stress, the equivalent strain and the equivalent strain-rate at least over a limited rang...
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ISBN:
(纸本)9783038351801
The mechanical behaviour of a superplastic material is often modelled by the power law relationship between the equivalent flow stress, the equivalent strain and the equivalent strain-rate at least over a limited range of strain rates. This paper introduces an original mathematicalmodelling to determine the superplastic material constants m, n and K by means of experimental tests carried out using a standard forming die geometry.
In this work, we develop mathematical models describing the interactions between human papillomavirus (HPV)-infected cells and the immune system. We start with simple models in order to capture the most important feat...
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In this work, we develop mathematical models describing the interactions between human papillomavirus (HPV)-infected cells and the immune system. We start with simple models in order to capture the most important features of such interactions. Then, we proceed to consider fundamental immunological characteristics for the models. For the numerical counterpart, we develop and implement efficient numerical discretizations of our models in order to illustrate the behavior of the schemes using different initial conditions, which represent the degree of infection of the disease. Understanding such interactions is of paramount importance for the prevention and the potential eradication of the infection. One main goal of this research is to analyze how and under what circumstances the immune system succeeds in eliminating HPV-infected cells.
This paper describes review of the relevant literature about two phase analysis of air and particle flow through human airways. An emphasis of the review is placed on elaborating the steps involved in two phase analys...
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This paper describes review of the relevant literature about two phase analysis of air and particle flow through human airways. An emphasis of the review is placed on elaborating the steps involved in two phase analysis, which are Geometric modelling methods and mathematical models. The first two parts describes various approaches that are followed for constructing an Airway model upon which analysis are conducted. Broad two categories of geometric modelling viz. Simplified modelling and Accurate modelling using medical scans are discussed briefly. Ease and limitations of simplified models, then examples of CT based models are discussed. In later part of the review different mathematical models implemented by researchers for analysis are briefed. mathematical models used for Air and Particle phases are elaborated separately.
The mathematical simulation of the evacuation process has a wide and largely untapped scope of application within the aircraft industry. The function of the mathematical model is to provide insight into complex behavi...
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The mathematical simulation of the evacuation process has a wide and largely untapped scope of application within the aircraft industry. The function of the mathematical model is to provide insight into complex behaviour by allowing designers, legislators, and investigators to ask 'what if' questions. Such a model, EXODUS, is currently under development, and this paper describes its evolution and potential applications. EXODUS is an egress model designed to simulate the evacuation of large numbers of individuals from an enclosure, such as an aircraft. The model tracks the trajectory of each individual as they make their way out of the enclosure or are overcome by fire hazards, such as heat and toxic gases. The software is expert system-based, the progressive motion and behaviour of each individual being determined by a set of heuristics or rules. EXODUS comprises five core interacting components: (i) the Movement Submodel - controls the physical movement of individual passengers from their current position to the most suitable neighbouring location;(ii) the behaviour Submodel - determines an individual's response to the current prevailing situation;(iii) the Passenger Submodel - describes an individual as a collection of 22 defining attributes and variables;(iv) the Hazard Submodel - controls the atmospheric and physical environment;and (v) the Toxicity Submodel - determines the effects on an individual exposed to the fire products, heat, and narcotic gases through the Fractional Effective Dose calculations. These components are briefly described and their capabilities and limitations are demonstrated through comparison with experimental data and several hypothetical evacuation scenarios.
A mathematical model of angiography catheters is developed in order to carry out parameter studies to determine the optimum combination of materials and geometric configuration for several different loading situations...
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A mathematical model of angiography catheters is developed in order to carry out parameter studies to determine the optimum combination of materials and geometric configuration for several different loading situations. The objective is to replace some of the expensive experimental trials currently used with the modelling studies. Analytical and finite element software packages are developed to study the thermomechanical behaviour of the catheters. Verification of the developed software and the finite element models is carried out. Closed-form solutions for in-line loading of the tubes are used to verify the developed software, which will be extended to deal with complex curved configurations in the future. Parameter studies on the effect of geometric characteristics on the ply stresses under the different loading situations are also carried out.
In September 2011, the University of Essex, UK, hosted an interdisciplinary conference, mathematical and Theoretical Ecology 2011 (MATE 2011), with the theme of 'Linking models with ecological processes'. The ...
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In September 2011, the University of Essex, UK, hosted an interdisciplinary conference, mathematical and Theoretical Ecology 2011 (MATE 2011), with the theme of 'Linking models with ecological processes'. The aim of the meeting was to create discussion and debate between modellers and empiricists working in ecology. A wide range of topics were discussed at the meeting including evolutionary and community models of ecosystem structure, epidemiological models, non-linear models of population dynamics, spatiotemporal models, individual and collective movement behaviour, and applications of ecological models to engineering problems. In this introductory article, we provide a report of the MATE 2011 meeting, and briefly review the most recent relevant research in the fields of mathematical and theoretical ecology. We introduce and summarise the eight contributed articles that were selected for this special issue. The diverse range of topics and the wide range of mathematical, statistical and computational tools used illustrate the broad appeal and depth of research in the rich field of mathematical and theoretical ecology. (C) 2013 Elsevier B.V. All rights reserved.
We describe in this paper a new method to perform automated mathematicalmodelling for financial time series prediction using Fuzzy Logic Techniques, Dynamical Systems and Fractal Theory. The main idea in this paper i...
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ISBN:
(纸本)0780332369
We describe in this paper a new method to perform automated mathematicalmodelling for financial time series prediction using Fuzzy Logic Techniques, Dynamical Systems and Fractal Theory. The main idea in this paper is that using Fuzzy Logic techniques we can simulate and automate the reasoning process of the human experts in mathematicalmodelling for financial time series prediction. Our new method for automated modelling consists of three main parts: Time Series Analysis, Developing a set of Admissible Models and Selecting the 'Best' model. Our method for Time Series Analysis consists in the use of the fractal dimension of a set of points as a measure of the geometrical complexity of the time series. Our method for developing a set of admissible dynamical systems models is based on the use of Fuzzy Logic techniques to simulate the decision process of the human experts in modelling financial problems. The selection of the 'best' model for Financial Time Series Prediction (FTSP) is done using heuristics from the experts and statistical calculations. This new method can be implemented as a computer program and can be considered an intelligent system for automated mathematicalmodelling for FTSP.
One of the objectives of machine learning is to enable intelligent systems to acquire knowledge in a highly automated manner. In systems modelling and control engineering, fuzzy systems have shown to be highly suitabl...
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One of the objectives of machine learning is to enable intelligent systems to acquire knowledge in a highly automated manner. In systems modelling and control engineering, fuzzy systems have shown to be highly suitable for the modelling of complex and uncertain systems. Recently, the interest in fuzzy systems has shifted from the seminal ideas about modelling the process or the behaviour of operators by knowledge acquisition towards a data-driven approach. Reasons to choose fuzzy systems instead of modelling techniques such as neural networks, radial basis functions, genetic algorithms or splines, are mainly the possibility of integrating logical information processing with the attractive mathematical properties of general function approximators. Furthermore, the rule-based structure of fuzzy systems makes analysis easier. The fuzzy sets in the rules represent linguistic qualitative terms that approximate the human-like way of information quantization. However, many of the data-driven fuzzy modelling algorithms that have been developed, aim at good numerical approximation and pay little attention to the semantical properties of the resulting rule base. In this article, we briefly discuss different approaches to data-intensive fuzzy modelling reported in the literature. Next, we present a data-driven approach to fuzzy modelling that provides the user with both accurate and transparent rule bases. The method has two main steps: data exploration by means of fuzzy clustering and fuzzy set aggregation by means of similarity analysis. First, fuzzy relations are identified in the product space of the system's variables and are described by means of fuzzy production rules. Compatible fuzzy concepts defined for the individual variables are then identified and aggregated to produce generalizing concepts, giving a comprehensible rule base with increased semantic properties. The transparent fuzzy modelling approach is demonstrated on a real world problem concerning the modellin
The reason for the present upsurge of interest in intelligent control is that the present generation of control systems are incapable, to a greater or less extent, of dealing with problems of a certain complexity. For...
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The reason for the present upsurge of interest in intelligent control is that the present generation of control systems are incapable, to a greater or less extent, of dealing with problems of a certain complexity. Fortunately, human operators are often experts in keeping the complex control systems on the right track. In this paper a method for controller design has been investigated based on a concept of developing a mathematical model for the behaviour of the human operator of the process. This method treats the human operator behaviour as a dynamic process by itself, transformed from the dynamics of the unknown process to be controlled. There are three phases for controller design, observation, modelling and testing phases during which the available observed data are used for training the system and testing it. The method has been successfully applied to control a nonlinear process using computer simulation.
The objective of the paper is to present a mathematical model for analysis of prestressed cable structures with flexible contour beam. The proposed numerical procedures are based on a discrete scheme according to the ...
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The objective of the paper is to present a mathematical model for analysis of prestressed cable structures with flexible contour beam. The proposed numerical procedures are based on a discrete scheme according to the finite element method. A reliable model of the interaction of the flexible contour beam with the cable network enables the achievement of more efficient solutions in the design analysis. Geometrical nonlinearity is accounted for in the cable net substructure and the contour beam is modelled by linear beam elements. Equations are solved by iterative methods and explicit time integration. The described numerical technique has been employed to model prestressing, static and dynamic behaviour. Theoretical results have been compared to experimental data and used in practical applications. (C) 2001 Civil-Comp Ltd. and Elsevier Science Ltd. All rights reserved.
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