Downloads & Free Reading Options - Results

Mathematical Modeling with Differential Equations and the SAGE Program; by David Joyner. Used for MP520 Computer Systems in Medicine for Radiological Technologies University, South Bend, Indiana Campus. Uploaded by Gerard Arthus and released into the Public Domain under the Creative Commons License Non-Attribute.

Mathematical Modeling with Differential Equations and the SAGE Program; by David Joyner. Used for MP520 Computer Systems in Medicine for Radiological Technologies University, South Bend, Indiana Campus. Uploaded by Gerard Arthus and released into the Public Domain under the Creative Commons License Non-Attribute.

We consider the problem of quantum behavior in the finite background. Introduction of continuum or other infinities into physics leads only to technical complications without any need for them in description of empirical observations. The finite approach makes the problem constructive and more tractable. We argue that quantum behavior is a natural consequence of symmetries of dynamical systems. It is a result of fundamental impossibility to trace identity of indistinguishable objects in their evolution - only information about invariant combinations of such objects is available. We demonstrate that any quantum dynamics can be embedded into a simple permutation dynamics. Quantum phenomena, such as interferences, arise in invariant subspaces of permutation representations of the symmetry group of a system. Observable quantities can be expressed in terms of the permutation invariants.

We consider the problem of quantum behavior in the finite background. Introduction of continuum or other infinities into physics leads only to technical complications without any need for them in description of empirical observations. The finite approach makes the problem constructive and more tractable. We argue that quantum behavior is a natural consequence of symmetries of dynamical systems. It is a result of fundamental impossibility to trace identity of indistinguishable objects in their evolution - only information about invariant combinations of such objects is available. We demonstrate that any quantum dynamics can be embedded into a simple permutation dynamics. Quantum phenomena, such as interferences, arise in invariant subspaces of permutation representations of the symmetry group of a system. Observable quantities can be expressed in terms of the permutation invariants.

We consider the problem of quantum behavior in the finite background. Introduction of continuum or other infinities into physics leads only to technical complications without any need for them in description of empirical observations. The finite approach makes the problem constructive and more tractable. We argue that quantum behavior is a natural consequence of symmetries of dynamical systems. It is a result of fundamental impossibility to trace identity of indistinguishable objects in their evolution - only information about invariant combinations of such objects is available. We demonstrate that any quantum dynamics can be embedded into a simple permutation dynamics. Quantum phenomena, such as interferences, arise in invariant subspaces of permutation representations of the symmetry group of a system. Observable quantities can be expressed in terms of the permutation invariants.

Mathematical modeling forms a bridge between the study of mathematics and the application of mathematics with the intent of explaining or predicting real world behavior. In their book A First Course in Mathematical Modeling, Frank R. Giordano, Maurice D. Weir, and William P. Fox provide an introduction to the entire modeling process. Model verification, an important step(in the modeling process, often requires the analysis of vast amounts of data, making computational support essential. Mathematical Modeling Using MA MATLAB acts as a companion resource to A First Course in Mathematical Modeling with the goal of guiding the reader to a fuller understanding of the modeling process through the employment of MATLAB's powerful computational capabilities. In it, the reader is led through a series of examples, each building upon the previous, which apply MATLAB's computational power to various modeling scenarios. While not intended as a text in modeling, Mathematical Modeling Using MA TIAB is a useful resource for the novice modeler interested in tackling problems too large to be performed manually

Mathematical modeling forms a bridge between the study of mathematics and the application of mathematics with the intent of explaining or predicting real world behavior. In their book A First Course in Mathematical Modeling, Frank R. Giordano, Maurice D. Weir, and William P. Fox provide an introduction to the entire modeling process. Model verification, an important step(in the modeling process, often requires the analysis of vast amounts of data, making computational support essential. Mathematical Modeling Using MA MATLAB acts as a companion resource to A First Course in Mathematical Modeling with the goal of guiding the reader to a fuller understanding of the modeling process through the employment of MATLAB's powerful computational capabilities. In it, the reader is led through a series of examples, each building upon the previous, which apply MATLAB's computational power to various modeling scenarios. While not intended as a text in modeling, Mathematical Modeling Using MA TIAB is a useful resource for the novice modeler interested in tackling problems too large to be performed manually

The thyristor is a power electronics device that is widely used in various electrical appliances due to its lower on-conduction losses, easyavailability, lower switching loss, greater efficiency and cost-benefit. Mostly a thyristor is used in rectifiers and variable-speed drives. Almost 70% of loads used in the world consists of induction motors in various types and forms. In this work, a thyristor-based controller is used to control the speed of a single phase induction motor by adjusting the firing angle for the gate terminal of the thyristor. Depending upon the firing angle, the output voltage, output current, speed, power factor and the total harmonic distortion are varied which is analyzed through MATLAB/Simulink. Further curve fitting technique is used to formulate the mathematical relationships between varying parameters concerning thyristor’s firing angle. The findings of this work are helpful to achieve the best curve fit model for varying parameters concerningthe thyristor firing angle. 

The thyristor is a power electronics device that is widely used in various electrical appliances due to its lower on-conduction losses, easyavailability, lower switching loss, greater efficiency and cost-benefit. Mostly a thyristor is used in rectifiers and variable-speed drives. Almost 70% of loads used in the world consists of induction motors in various types and forms. In this work, a thyristor-based controller is used to control the speed of a single phase induction motor by adjusting the firing angle for the gate terminal of the thyristor. Depending upon the firing angle, the output voltage, output current, speed, power factor and the total harmonic distortion are varied which is analyzed through MATLAB/Simulink. Further curve fitting technique is used to formulate the mathematical relationships between varying parameters concerning thyristor’s firing angle. The findings of this work are helpful to achieve the best curve fit model for varying parameters concerningthe thyristor firing angle. 

The Javelin antitank weapon system will replace the Dragon m Infantry and Combat Engineer battalions on a one for one basis. The tactics and techniques for Javelin employment will closely mirror those used for Dragon and TOW missile systems. This thesis examines the effectiveness of Javelin versus Dragon and examines a different employment method. The thesis goals are: • To investigate the suitability of Janus(A) to model the employment of various weapon systems. • To compare Javelin against Dragon, using measures of effectiveness and performance outlined in the Test and Evaluation Plan (TEP). • To examine how changes in the composition and tactical employment of anti-armor weapon systems influence their lethality and survivability, potentially suggesting a more effective employment method. The data generated from the simulated force-on-force scenarios is analyzed using graphical, statistical, and mathematical modeling techniques. The results could benefit the Army's Training and Doctrine Command in their combat development and combat effectiveness analysis.

The Javelin antitank weapon system will replace the Dragon m Infantry and Combat Engineer battalions on a one for one basis. The tactics and techniques for Javelin employment will closely mirror those used for Dragon and TOW missile systems. This thesis examines the effectiveness of Javelin versus Dragon and examines a different employment method. The thesis goals are: • To investigate the suitability of Janus(A) to model the employment of various weapon systems. • To compare Javelin against Dragon, using measures of effectiveness and performance outlined in the Test and Evaluation Plan (TEP). • To examine how changes in the composition and tactical employment of anti-armor weapon systems influence their lethality and survivability, potentially suggesting a more effective employment method. The data generated from the simulated force-on-force scenarios is analyzed using graphical, statistical, and mathematical modeling techniques. The results could benefit the Army's Training and Doctrine Command in their combat development and combat effectiveness analysis.

Solid oxide fuel cells (SOFC) are the most efficient devices for directly converting the chemical energy of a fuel into electrical energy. This is one of the main reasons why these fuel cells have received a lot of attention from the scientific community and from several developers who have invested in the use of this technology in various applications. Biogas is one of the products of anaerobic decomposition (absence of gaseous oxygen) of organic matter, which occurs due to the action of certain types of bacteria. Biogas is mainly composed of methane (CH4) and carbon dioxide (CO2) and its use in solid oxide fuel cells has been investigated since Biogas is a renewable biofuel. The aim of this paper was to perform mathematical modeling of a solid oxide fuel cell operating on biogas. The results confirmed that the overall efficiency of the system is above 94% and the largest irreversibilities of the system are related to heat exchangers.

This paper is devoted to methodologies in the field of mathematical foundations of information technology and computer sciences. The theoretical foundations of mathematical modeling of dynamic systems are briefly presented. Various aspects of the concept of a model are considered. The division into types of models is presented. The steps of the mathematical modeling process are detailed. Basic requirements for mathematical models are formulated. The main approaches used in the process of mathematical modeling are described.

This paper is devoted to methodologies in the field of mathematical foundations of information technology and computer sciences. The theoretical foundations of mathematical modeling of dynamic systems are briefly presented. Various aspects of the concept of a model are considered. The division into types of models is presented. The steps of the mathematical modeling process are detailed. Basic requirements for mathematical models are formulated. The main approaches used in the process of mathematical modeling are described.

Magnetostrictive wires of diameter in the nanometer scale have been proposed for application as acoustic sensors [Downey et al., 2008], [Yang et al., 2006]. The sensing mechanism is expected to operate in the bending regime. In this work we derive a variational theory for the bending of magnetostrictive nanowires starting from a full 3-dimensional continuum theory of magnetostriction. We recover a theory which looks like a typical Euler-Bernoulli bending model but includes an extra term contributed by the magnetic part of the energy. The solution of this variational theory for an important, newly developed magnetostricitve alloy called Galfenol (cf. [Clark et al., 2000]) is compared with the result of experiments on actual nanowires (cf. [Downey, 2008]) which shows agreement.

This research explores a continuous-time mathematical model that outlines the transmission dynamics of the dengue virus across different regions, in-volving both human and mosquito hosts. We propose an optimal strat-egy that includes awareness campaigns, safety measures, and health inter-ventions in dengue-endemic areas, with the goal of reducing transmission between individuals and mosquitoes, thus lowering human infections and eliminating the virus in mosquito populations. Utilizing the discrete-time Pontryagin’s maximum principle, we identify optimal control measures and employ an iterative approach to solve the optimal system. Numerical sim-ulations are carried out using MATLAB, and a cost-effectiveness ratio is computed. Through an in-depth cost-effectiveness analysis, we highlight the effectiveness of strategies focused on protecting at-risk populations, pre-venting contact between infected humans and mosquitoes, and promoting the use of quarantine facilities as the most powerful methods for controlling the spread of the dengue virus.

This research explores a continuous-time mathematical model that outlines the transmission dynamics of the dengue virus across different regions, in-volving both human and mosquito hosts. We propose an optimal strat-egy that includes awareness campaigns, safety measures, and health inter-ventions in dengue-endemic areas, with the goal of reducing transmission between individuals and mosquitoes, thus lowering human infections and eliminating the virus in mosquito populations. Utilizing the discrete-time Pontryagin’s maximum principle, we identify optimal control measures and employ an iterative approach to solve the optimal system. Numerical sim-ulations are carried out using MATLAB, and a cost-effectiveness ratio is computed. Through an in-depth cost-effectiveness analysis, we highlight the effectiveness of strategies focused on protecting at-risk populations, pre-venting contact between infected humans and mosquitoes, and promoting the use of quarantine facilities as the most powerful methods for controlling the spread of the dengue virus.

Click here to view the University of Florida catalog record

This article addresses the logistics of implementing projects in an undergraduate mathematics class and is intended both for new instructors and for instructors who have had negative experiences implementing projects in the past. Project implementation is given for both lower and upper division mathematics courses with an emphasis on mathematical modeling and data collection. Projects provide tangible connections to course content which can motivate students to learn at a deeper level. Logistical pitfalls and insights are highlighted as well as descriptions of several key implementation resources. Effective assessment tools, which allowed me to smoothly adjust to student feedback, are demonstrated for a sample class. As I smoothed the transition into each project and guided students through the use of the technology, their negative feedback on projects decreased and more students noted how the projects had enhanced their understanding of the course topics. Best practices learned over the years are given along with project summaries and sample topics. These projects were implemented at a small liberal arts university, but advice is given to extend them to larger classes for broader use.

This article addresses the logistics of implementing projects in an undergraduate mathematics class and is intended both for new instructors and for instructors who have had negative experiences implementing projects in the past. Project implementation is given for both lower and upper division mathematics courses with an emphasis on mathematical modeling and data collection. Projects provide tangible connections to course content which can motivate students to learn at a deeper level. Logistical pitfalls and insights are highlighted as well as descriptions of several key implementation resources. Effective assessment tools, which allowed me to smoothly adjust to student feedback, are demonstrated for a sample class. As I smoothed the transition into each project and guided students through the use of the technology, their negative feedback on projects decreased and more students noted how the projects had enhanced their understanding of the course topics. Best practices learned over the years are given along with project summaries and sample topics. These projects were implemented at a small liberal arts university, but advice is given to extend them to larger classes for broader use.

This article addresses the logistics of implementing projects in an undergraduate mathematics class and is intended both for new instructors and for instructors who have had negative experiences implementing projects in the past. Project implementation is given for both lower and upper division mathematics courses with an emphasis on mathematical modeling and data collection. Projects provide tangible connections to course content which can motivate students to learn at a deeper level. Logistical pitfalls and insights are highlighted as well as descriptions of several key implementation resources. Effective assessment tools, which allowed me to smoothly adjust to student feedback, are demonstrated for a sample class. As I smoothed the transition into each project and guided students through the use of the technology, their negative feedback on projects decreased and more students noted how the projects had enhanced their understanding of the course topics. Best practices learned over the years are given along with project summaries and sample topics. These projects were implemented at a small liberal arts university, but advice is given to extend them to larger classes for broader use.

This study explores a continuous spatio-temporal mathematical model to illustrate the dynamics of Monkeypox virus spread across various regions, considering both human and animal hosts. We propose a comprehensive strategy that includes awareness campaigns, security measures, and health interventions in areas where the virus is prevalent. The goal is to reduce transmission between humans and animals, thereby decreasing human infections and eradicating the virus in animal populations. Our model, which integrates spatial variables, accurately reflects the geographical spread of the virus and the impact of interventions, followed by the implementation and analysis of an applicable optimal control problem. Optimal control theory methods are applied in this work to demonstrate the existence of optimal control and the necessary conditions for optimality. We conduct numerical simulations using MATLAB with the forward-backward sweep method, revealing the efficiency of strategies focused on protecting vulnerable populations, preventing contact with infected individuals and animals, and promoting the use of quarantine facilities as the most effective means to control the spread of the Monkeypox virus. Additionally, the study examines the socio-economic impacts of the virus and the benefits of timely intervention. This approach provides valuable insights for policymakers and public health officials in managing and controlling the spread of Monkeypox.

In this paper we study the gravitational field of a straight string generated from a class of nonlinear sigma models, specifically the Skyrme model without a twist and the Skyrme model with a twist (the twisted Skyrmion string). The twist term, $mkz$, is included to stabilize the vortex solution. To model the effects of gravity, we replace the Minkowski tensor, $\eta^{\mu\nu}$, in the standard Skyrme Lagrangian density with a space-time metric tensor, $g^{\mu\nu}$, assumed to be static and cylindrically symmetric. The Einstein equations for the metric and field components are then derived. This work is still in progress.

In this paper we study the gravitational field of a straight string generated from a class of nonlinear sigma models, specifically the Skyrme model without a twist and the Skyrme model with a twist (the twisted Skyrmion string). The twist term, $mkz$, is included to stabilize the vortex solution. To model the effects of gravity, we replace the Minkowski tensor, $\eta^{\mu\nu}$, in the standard Skyrme Lagrangian density with a space-time metric tensor, $g^{\mu\nu}$, assumed to be static and cylindrically symmetric. The Einstein equations for the metric and field components are then derived. This work is still in progress.

In this paper we study the gravitational field of a straight string generated from a class of nonlinear sigma models, specifically the Skyrme model without a twist and the Skyrme model with a twist (the twisted Skyrmion string). The twist term, $mkz$, is included to stabilize the vortex solution. To model the effects of gravity, we replace the Minkowski tensor, $\eta^{\mu\nu}$, in the standard Skyrme Lagrangian density with a space-time metric tensor, $g^{\mu\nu}$, assumed to be static and cylindrically symmetric. The Einstein equations for the metric and field components are then derived. This work is still in progress.

In this paper we study the gravitational field of a straight string generated from a class of nonlinear sigma models, specifically the Skyrme model without a twist and the Skyrme model with a twist (the twisted Skyrmion string). The twist term, $mkz$, is included to stabilize the vortex solution. To model the effects of gravity, we replace the Minkowski tensor, $\eta^{\mu\nu}$, in the standard Skyrme Lagrangian density with a space-time metric tensor, $g^{\mu\nu}$, assumed to be static and cylindrically symmetric. The Einstein equations for the metric and field components are then derived. This work is still in progress.

The Coastal Modeling System (CMS) is an integrated numerical modeling system for simulating nearshore waves, currents, water levels, salinity and sediment transport, and morphology change. The CMS was designed and developed for coastal inlets and navigation applications, including channel performance and sediment exchange between inlets and adjacent beaches. The present report provides an updated description of the mathematical formulations and numerical methods of hydrodynamic, salinity and sediment transport, and morphology change model CMS-Flow. The CMS-Flow uses the Finite Volume Method on Cartesian grids and has both fully explicit and fully implicit time stepping schemes. A detailed description of the explicit time stepping scheme was provided in Militello et al. (2004) and Buttolph et al. (2006). The present report focuses on the recent changes in the mathematical formulations, and the implicit time stepping schemes. The CMS-Wave and CMS-Flow models are tightly coupled within a single inline code. The CMS-Wave and CMS-Flow grids may be the same or have different spatial extents and resolutions. The hydrodynamic model includes physical processes such as advection, turbulent mixing, combined wave-current bottom friction; wave mass flux; wind, atmospheric pressure, wave, river, and tidal forcing; Coriolis force; and the influence of coastal structures. The implicit hydrodynamic model is coupled to a nonequilibrium transport model of multiple-sized total-load sediments. The model includes physical processes such as hiding and exposure, bed sorting and gradation, bed slope effects, nonerodible surfaces, and avalanching.

The goal is the development of a time-domain acoustical method for investigating the spatial and temporal stochastic variations in fish density within fish schools, and thereby to study the statistical fluctuations in the scattering of sound from these objects.

Soldering is the default joining proce0073s in the electronic packaging industry. Solder joints are obtained by interaction of the substrate (mostly copper) with the molten solder. The dissolution kinetics of copper and the growth of intermetallic compound (IMC) during soldering process are concurrent processes. The dissolution of the metal from the substrate components is even more critical due to ever increasing miniaturization of the electronic components.The assessment of base metal lost during the process is another important subject being investigated by the researchers in the last two decades. Extensive experimentation is done to quantify the IMC thickness and metal dissolution for various combinations of substrate metal and solders. As a matter of fact these experiments are time consuming and expensive. Moreover, the experimental results have the application to a limited domain. Various models have been suggested by researchers to quantify the substrate thickness lost and IMC growth during soldering. Most of the existing models to estimate the IMC growth and metal dissolution during the soldering process are heavily based on the experimental data. These models do not depict the actual physics of the process. In the present study a review of the modeling techniques has been done and a model has been proposed which is based on the diffusion of and interface kinetics during soldering process. The proposed one-dimensional model has been solved and compared with the experimental data. The present model has a good potential to be extended in two and possibly three dimensions and incorporation of scalloped IMC in order to capture the complete physics of the process.

Some theoretical questions involved in the mathematical modeling of the kinetics of complex chemical process are discussed. The analysis is carried out for the homogeneous oxidation of ethylbenzene in the liquid phase. Particular attention is given to the determination of the general characteristics of chemical systems from an analysis of mathematical models developed on the basis of linear algebra.

A study is performed under NASA contract to evaluate data from an AN/FPS-16 radar installed for support of flight programs at Dryden Flight Research Facility of NASA Ames Research Center. The purpose of this study is to provide information necessary for improving post-flight data reduction and knowledge of accuracy of derived radar quantities. Tracking data from six flights are analyzed. Noise and bias errors in raw tracking data are determined for each of the flights. A discussion of an altitude bias error during all of the tracking missions is included. This bias error is defined by utilizing pressure altitude measurements made during survey flights. Four separate filtering methods, representative of the most widely used optimal estimation techniques for enhancement of radar tracking data, are analyzed for suitability in processing both real-time and post-mission data. Additional information regarding the radar and its measurements, including typical noise and bias errors in the range and angle measurements, is also presented. This report is in two parts. This is part 2, a discussion of the modeling of propagation path errors.

A study is performed under NASA contract to evaluate data from an AN/FPS-16 radar installed for support of flight programs at Dryden Flight Research Facility of NASA Ames Research Center. The purpose of this study is to provide information necessary for improving post-flight data reduction and knowledge of accuracy of derived radar quantities. Tracking data from six flights are analyzed. Noise and bias errors in raw tracking data are determined for each of the flights. A discussion of an altitude bias error during all of the tracking missions is included. This bias error is defined by utilizing pressure altitude measurements made during survey flights. Four separate filtering methods, representative of the most widely used optimal estimation techniques for enhancement of radar tracking data, are analyzed for suitability in processing both real-time and post-mission data. Additional information regarding the radar and its measurements, including typical noise and bias errors in the range and angle measurements, is also presented. This report is in two parts. This is part 2, a discussion of the modeling of propagation path errors.

In this study, thin layer drying experiments were conducted to compute drying characteristics of fermented cocoa beans in open sun and indirect natural convection solar dryer. The drying experiments were conducted at the same time for comparison. Three different thin layers drying of the fermented beans were examined under field conditions for Akure, Nigeria. The drying process took place only in the falling rate period. The drying curves obtained from the experimental data were fitted to thirteen (13) different thin layer mathematical models. All the models were compared according to three evaluation parameters. These include coefficient of determination (R2), Root mean square error (RMSE) and Chi-square (X2).The results showed that increasing drying air temperature resulted to shorter drying times. The Vermal et al. model was found to be the most suitable for describing the drying curve of the convective indirect solar drying process of cocoa beans with R2 = 0.9562, X2=0.0069 and RMSE=0.0067; while, the Midilli and Kucuk model, best described the drying curve of fermented cocoa beans under open sun with R2 = 0.9866, X2=0.0024 and RMSE=0.0023.

This paper presents an intervention study whose aim was to promote teacher beliefs about mathematics and learning mathematics and student competences in mathematical modeling. In the intervention, teachers received written curriculum materials about mathematical modeling. The concept underlying the materials was based on constructivist ideas and findings from mathematics education. Teacher beliefs about mathematics, learning and self-efficacy were expected to have a major impact on their classroom practices. We therefore assessed teacher beliefs about the usefulness of mathematics, learning (constructivist and socio-constructivist beliefs) and teacher self-efficacy when teaching modeling (teacher or class level variable). The student level variables assessed were modeling competence and other individual factors, such as basic mathematical skills and cognitive abilities. The effectiveness of the intervention was measured in a pre-post control group design using multilevel structural equation modeling. The results showed no direct effect of the intervention on student modeling competence. However, they did reveal that the intervention had a significant effect on teacher beliefs about learning (constructivist and socio-constructivist view) and an effect of these teacher beliefs about learning on student modeling competence. Further, the results showed that students' gains in modeling competence is not only mediated by teacher beliefs, but also influenced by individual factors. Implications for teaching as well as limitations of the study are discussed.

This paper presents an intervention study whose aim was to promote teacher beliefs about mathematics and learning mathematics and student competences in mathematical modeling. In the intervention, teachers received written curriculum materials about mathematical modeling. The concept underlying the materials was based on constructivist ideas and findings from mathematics education. Teacher beliefs about mathematics, learning and self-efficacy were expected to have a major impact on their classroom practices. We therefore assessed teacher beliefs about the usefulness of mathematics, learning (constructivist and socio-constructivist beliefs) and teacher self-efficacy when teaching modeling (teacher or class level variable). The student level variables assessed were modeling competence and other individual factors, such as basic mathematical skills and cognitive abilities. The effectiveness of the intervention was measured in a pre-post control group design using multilevel structural equation modeling. The results showed no direct effect of the intervention on student modeling competence. However, they did reveal that the intervention had a significant effect on teacher beliefs about learning (constructivist and socio-constructivist view) and an effect of these teacher beliefs about learning on student modeling competence. Further, the results showed that students' gains in modeling competence is not only mediated by teacher beliefs, but also influenced by individual factors. Implications for teaching as well as limitations of the study are discussed.

This investigation is motivated by the need to study the cyclic plasticity response of standard aerospace fasteners within the context of finite element analysis. The available literature on mathematical models of plasticity along with their implementation in finite element procedures was reviewed. The investigation was limited to models of rate-independent plasticity based on the existence of a yield surface and the incremental (rate-type) theory of plasticity. Section II of the report introduces certain definitions and basic concepts including a discussion of the typical response of metals to cyclic loading. The mathematical models of the plastic behavior of metals are reviewed in Section III. Section IV covers the finite element implementation of certain models. A summary and some recommendations for future investigations are presented in Section V. (Author)

This project examines and assesses the extent to which U.S. military policy has effectively interpreted and responded to the military implications of Soviet weapons innovations. It focuses on the contributions of Soviet weapons innovations to military mission performance, and also examines the ability of the Soviet weapons innovation process to offer a militarily significant breakout option. Three related lines of inquiry were pursued. First, we examined the Soviet approach to weapons innovation as it is portrayed in their force planning and weapons evaluation literature. Next we analyzed the Soviet approach to measuring the relative contributions of weapons innovation efforts towards improving mission capabilities; and third, we assessed the degree to which the Soviets have the capacity for 'breakout' -- significantly improving their military capabilities in a short period of time -- through weapons innovation. Part I addressed one aspect of the second task. In part II we take a closer look at Soviet mathematical modeling related to notions of strategic technology innovation and strategic force development from their efforts to measure the nuclear balance. Keywords: Mathematical models; Weapon system effectiveness; Mission profiles; Innovations; Foreign technology.

This document is a final report of the research sponsored by AFOSR under contract No. F49620-91-C-0048-P0002 with Stanford University. This research effort focused on the mathematical modeling and numerical simulation of the dynamics of flexible structures undergoing large overall motions. The results reported below fall within the following areas: (i) Enhanced numerical models for shell intersections, (ii) Asymptotic methods for nonlinear shells, and (iii) Conserving time-stepping algorithms for nonlinear dynamics. (AN)

This document is a final report of the research sponsored by AFOSR under contract No. F49620-91-C-0048-P0002 with Stanford University. This research effort focused on the mathematical modeling and numerical simulation of the dynamics of flexible structures undergoing large overall motions. The results reported below fall within the following areas: (i) Enhanced numerical models for shell intersections, (ii) Asymptotic methods for nonlinear shells, and (iii) Conserving time-stepping algorithms for nonlinear dynamics. (AN)

This technical note describes Microwave Landing System (MLS) and Precision Distance Equipment (DME/P) mathematical modeling performed for runway 19L, Andrews Air Force Base (ADW), Camp Springs, Maryland. This study evaluates the effects of scattering and shadowing from selected buildings, hangars, aircraft, and terrain. Results are provided as plots illustrating the predicted multipath levels, separation angles, and the resulting error plots from the worst case contributors. Scenarios were modeled to determine the effects of the multipath sources in the modeled environment. These resulting errors were analyzed and compared to error tolerance (FAA-STD-022d) to determine if the errors are acceptable. The effects of the ADW environment were analyzed and evaluated. It was determined that the proposed site will perform satisfactorily with no changes.

The objectives of the project 'Biological-Mathematical Modeling of Chronic Toxicity' were to study the factors affecting the fate of inhaled vapors in the body and to develop a mathematical model. The main accomplishments are: (1) A general pharmacokinetic model for inhalation administration, based on physiological parameters of the exposed subject and on physical and chemical properties of the inhaled substance, was defined. (2) Information on interspecies differences was extracted from the literature; partition coefficients of eight organic solvents were determined for eight tissues of three species (man, monkey, rat); steady state clearances calculated from pulmonary uptake, and intrinsic clearance determined from vapor distribution in rats were used in the model as elimination rate constants. (3) The models were used to evaluate the effects of the following parameters on uptake, distribution and elimination of inhaled vapors: solubility, metabolism, body build, interspecies differences, physical exertion, exposure duration, exposure repetition, and short-term excursion limit. (4) Nonlinear dependence of pulmonary uptake on exposure concentration was observed in the animal model. (5) Reduced pulmonary uptake and quantitative and qualitative changes in elimination were observed if two vapors were inhaled simultaneously.

A mathematical model has been developed which can be applied to evaluate the least-cost alternatives to meet the projected potable and non-potable water requirements of a US Army Corps-sized operation. It included the adaptation of the model to an existing solution technique, the Out-of-Kilter Algorithm (OKA), a search of the literature to obtain cost data for the various elements within the alternatives, a search of the literature for health and other related factors, a review of existing scenarios, a review of collateral issues pertinent to the production of water in an arid or semi-arid environment, and finally, proposed systems for the re-use of laundry and shower wastewaters. (Author)

An equivalence relation in the set of all square binary matrices is described in this work. It is discussed a combinatoric problem about finding the cardinal number and the elements of the factor set according to this relation. We examine the possibility to get some special elements of this factor set. We propose an algorithm, which solves these problems. The results we have received are used to describe the topology of the different weaving structures.

An equivalence relation in the set of all square binary matrices is described in this work. It is discussed a combinatoric problem about finding the cardinal number and the elements of the factor set according to this relation. We examine the possibility to get some special elements of this factor set. We propose an algorithm, which solves these problems. The results we have received are used to describe the topology of the different weaving structures.

An equivalence relation in the set of all square binary matrices is described in this work. It is discussed a combinatoric problem about finding the cardinal number and the elements of the factor set according to this relation. We examine the possibility to get some special elements of this factor set. We propose an algorithm, which solves these problems. The results we have received are used to describe the topology of the different weaving structures.

Thesis advisor, Roberto Cristi

System requirements for accompanying computer disc: Microsoft Windows 98+, MAC OS X, 128MB RAM, 266Mhz processor

Accurate theoretical results for interdigitated array of electrodes (IDAE) in semi-infinite cells can be found in the literature. However, these results are not always applicable when using finite cells. In this study, theoretical expressions for IDAE in a finite geometry cell are presented. At known current density, transient and steady state concentration profiles were obtained as well as the response time to a current step. Concerning the diffusion limited current, a lower bound was derived from the concentration profile and an upper bound was obtained from the limiting current of the semi-infinite case. The lower bound, which is valid when Kirchhoff's current law applies to the unit cell, can be useful to ensure a minimum current level during the design of the electrochemical cell. Finally, a criterion was developed defining when the behaviors of finite and semi-infinite cells are comparable. This allows to obtain higher current levels in finite cells, approaching that of the semi-infinite case. Examples with simulations were performed in order to illustrate and validate the theoretical results.

This article is from Microbes and Environments , volume 28 . Abstract In the past couple of decades, molecular ecological techniques have been developed to elucidate microbial diversity and distribution in microbial ecosystems. Currently, modern techniques, represented by meta-omics and single cell observations, are revealing the incredible complexity of microbial ecosystems and the large degree of phenotypic variation. These studies propound that microbiological techniques are insufficient to untangle the complex microbial network. This minireview introduces the application of advanced mathematical approaches in combination with microbiological experiments to microbial ecological studies. These combinational approaches have successfully elucidated novel microbial behaviors that had not been recognized previously. Furthermore, the theoretical perspective also provides an understanding of the plasticity, robustness and stability of complex microbial ecosystems in nature.

This article is from Microbes and Environments , volume 28 . Abstract In the past couple of decades, molecular ecological techniques have been developed to elucidate microbial diversity and distribution in microbial ecosystems. Currently, modern techniques, represented by meta-omics and single cell observations, are revealing the incredible complexity of microbial ecosystems and the large degree of phenotypic variation. These studies propound that microbiological techniques are insufficient to untangle the complex microbial network. This minireview introduces the application of advanced mathematical approaches in combination with microbiological experiments to microbial ecological studies. These combinational approaches have successfully elucidated novel microbial behaviors that had not been recognized previously. Furthermore, the theoretical perspective also provides an understanding of the plasticity, robustness and stability of complex microbial ecosystems in nature.