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2009

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Articles 451 - 480 of 693

Full-Text Articles in Mathematics

Teaching Statistics Must Be Adapted To Changing Circumstances: A Case Study From Hungarian Higher Education, Andras Komaromi Jan 2009

Teaching Statistics Must Be Adapted To Changing Circumstances: A Case Study From Hungarian Higher Education, Andras Komaromi

The Mathematics Enthusiast

Teaching statistics can bring up difficulties of various types for the teacher. Some of these are independent of the environment, i.e. they could occur at any place and time; some are specifically conditional on the surrounding circumstances. This paper presents an example for both of these kinds from the practice of two Hungarian teachers.


Calculating Dependent Probabilities, Mike Fletcher Jan 2009

Calculating Dependent Probabilities, Mike Fletcher

The Mathematics Enthusiast

In the 2004 European soccer competition France were one of the favourites to win the World Cup and Thierry Henry, their star forward, was one of the favourites to be top goal scorer. Bookkeepers were offering odds of 4 :1 on France winning the competition and odds of 8: 1 on Thierry Henry being the top scorer. A large number of punters went into betting shops in the United Kingdom and made a single bet that France would win the competition and that Thierry Henry would be top scorer. The counter clerks in the betting shops accepted the bets and …


Teacher Knowledge And Statistics: What Types Of Knowledge Are Used In The Primary Classroom?, Tim Burgess Jan 2009

Teacher Knowledge And Statistics: What Types Of Knowledge Are Used In The Primary Classroom?, Tim Burgess

The Mathematics Enthusiast

School curricula are increasingly advocating for statistics to be taught through investigations. Although the importance of teacher knowledge is acknowledged, little is known about what types of teacher knowledge are needed for teaching statistics at the primary school level. In this paper, a framework is described that can account for teacher knowledge in relation to statistical thinking. This framework was applied in a study that was conducted in the classrooms of four second-year teachers, and was used to explore the teacher knowledge used in teaching statistics through investigations. As a consequence, descriptions of teacher knowledge are provided and give further …


Comparision Of High Achievers With Low Achievers: Discussion Of Juter’S (2007) Article, T. P. Hutchinson Jan 2009

Comparision Of High Achievers With Low Achievers: Discussion Of Juter’S (2007) Article, T. P. Hutchinson

The Mathematics Enthusiast

The use of questionnaires and interviews to compare the responses to a mathematical task of high achievers with low achievers has limitations. The partial information that they have provides a way of comparing high and low achievers. Some references are given here to relevant task formats and theories. An example is given of how examinees’ performance with unusual task formats (specifically, answer-until-correct) may be analysed to throw light on the mathematical description of partial information.


A Trailer, A Shotgun, And A Theorem Of Pythagoras, William H. Kazez Jan 2009

A Trailer, A Shotgun, And A Theorem Of Pythagoras, William H. Kazez

The Mathematics Enthusiast

Counselor: Please tell the Court your name.

Expert Witness: My name is Will Kazez

Counselor: No, no, no! Your name is…

This is not a good start. I am not naturally a nervous person. I have survived teaching calculus to a large class that included the entire freshman football team of the University of Pennsylvania, but I've never been an Expert Witness. Even though I'm confident of the mathematics, I'm not sure I like the idea of being cross-examined. But still, I'm just rehearsing my testimony with the lawyer, and even if I've got my own name a little wrong, …


Using Calculus To Model The Growth Of L. Plantarum Bacteria, Erin Carey Jan 2009

Using Calculus To Model The Growth Of L. Plantarum Bacteria, Erin Carey

Undergraduate Journal of Mathematical Modeling: One + Two

Experimental data for the growth of Lactobacillus plantarum bacteria have been obtained over time, creating the need for mathematical means to model this data. We use the Gompertz model because it is a sigmoid function for a time series, where growth is slowest at the start and end of a time period. The Gompertz model is especially useful because it defines specific parameters that characterize the S-shaped curve. In addition, the Gompertz model uses relative growth, which is the logarithm of the given population compared to the initial population. This reflects the fact that bacteria grow exponentially. The important parameters …


Detecting Edges, Sam Maniscalo Jan 2009

Detecting Edges, Sam Maniscalo

Undergraduate Journal of Mathematical Modeling: One + Two

In human vision the first level of processing is edge detection. Edges are determined by the transitions from dark points to bright points in an image. For this paper, we consider an edge profile model representing a boundary or edge in an image. From this model we can determine the strength of the edge, the width of the edge, and either the transition from dark to bright to dark or the transition from bright to dark to bright. Our first step was to take the given edge profile and determine the type of edge that is represented and the characteristics …


Determination Of Azeotropy, Kyle Cogswell Jan 2009

Determination Of Azeotropy, Kyle Cogswell

Undergraduate Journal of Mathematical Modeling: One + Two

The ultimate goal of this paper is the determination of an azeotrope within a methanol-acetone system. An azeotrope is the point in a chemical system at which coexisting compositions of vapor and liquid phases are equal. The importance of this point lies in the fact that azeotropes are undesirable; they prevent one from completely separating a mixture through distillation. This state can occur over a range of temperatures and for the purposes of this paper there is only one azeotrope for each given temperature. All azeotropes occur at relative extrema in pressure. By finding these extrema, we find the mole …


Infection Of A Homogeneous Population By A Known Bacterium, Arthur Maknenko Jan 2009

Infection Of A Homogeneous Population By A Known Bacterium, Arthur Maknenko

Undergraduate Journal of Mathematical Modeling: One + Two

In order for the development of antibiotics and vaccines to be successful, the lifecycle and infection pattern of a pathogen must be studied well. In this paper, we study the rate of replication and the pattern of infection in a homogeneous population, which may or may not have an effective immunity or immunization program against the pathogen. We utilize three functions: one will determine the rate with which the pathogen replicates; the second will show the result of an infection by a single individual of a susceptible population without a removal rate; and the third will include the removal rate …


2009 Ford Mustang Performance Test, Daniel Fernandes Jan 2009

2009 Ford Mustang Performance Test, Daniel Fernandes

Undergraduate Journal of Mathematical Modeling: One + Two

Our goal is to find the time required for a 2009 Ford Mustang to accelerate from rest to 88 feet per second. We begin with three equations involving force, velocity, and force inverse, which is a value derived from Newton's Law, F=ma. The Mustang has three gears with three different gear ratios that must be used as the car accelerates. We found results from 2000 to 6000 RPMs for all three gears. Once the force inverse was found, we plotted the force inverse vs. velocity graph. The area beneath this curve from 0 to 88 feet per second is the …


Modulus Of Subgrade Reaction And Deflection, Austin Potts Jan 2009

Modulus Of Subgrade Reaction And Deflection, Austin Potts

Undergraduate Journal of Mathematical Modeling: One + Two

Differential equations govern the bending and deflection of roads under a concentrated load. Identifying critical parameters, such as the maximum deflection and maximum bending moments of a street supported by an elastic subgrade, is key to designing safe and reliable roadways. This project solves the underlying differential equation in pavement deflection and tests various parameters to highlight the importance in selecting proper foundation materials.


That's A Drag: The Effects Of Drag Forces, Shane Maxemow Jan 2009

That's A Drag: The Effects Of Drag Forces, Shane Maxemow

Undergraduate Journal of Mathematical Modeling: One + Two

Drag is a force that opposes motion due to an object's shape, material, and speed. This project defined what drag force is, derived the governing equation for drag and listed some applications of drag forces. Derivation of the drag equation was achieved using the Buckingham π theorem, a dimensional analysis tool. Lastly, this project explored the problem of how long and how far a dragster takes to stop once its parachute is deployed.


Biodiversity In A Florida Sandhill Ecosystem, Samantha Robertson Jan 2009

Biodiversity In A Florida Sandhill Ecosystem, Samantha Robertson

Undergraduate Journal of Mathematical Modeling: One + Two

This project compares two transects of land in the University of South Florida's Botanical Gardens for their biodiversity. The transects were chosen to represent a Florida sandhill ecosystem and the individual Longleaf Pine, Saw Palmetto, Turkey Oak, Laurel Oak and Live Oak specimens were counted. All other species above waist height were counted as "other"?. Once the individuals were counted, the Simpson's and Shannon-Wiener indices were calculated. Since the Shannon-Wiener index incorporates several diversity characteristics, it is typically more reliable than Simpson's. However, both biodiversity indices agreed that transect B was more diverse than transect A.


Repeatability Estimates Of Sloped Scattered Data, Angelique Waller Jan 2009

Repeatability Estimates Of Sloped Scattered Data, Angelique Waller

Undergraduate Journal of Mathematical Modeling: One + Two

Repeatability is the variance in data accumulated under fixed conditions. It is important for quality control as it costs both time and money to recalibrate tools and remanufacture machines. This project compares three methods for approximating the repeatability of a sloped scattered data set. The first method uses a linear approximation, the second involves rotating the data points, and the third calculates distance using right triangles. The methods are compared for both precision and ease of use.


Robotics Potential Fields, Jordi Lucero Jan 2009

Robotics Potential Fields, Jordi Lucero

Undergraduate Journal of Mathematical Modeling: One + Two

This problem was to calculate the path a robot would take to navigate an obstacle field and get to its goal. Three obstacles were given as negative potential fields which the robot avoided, and a goal was given a positive potential field that attracted the robot. The robot decided each step based on its distance, angle, and influence from every object. After each step, the robot recalculated and determined its next step until it reached its goal. The robot's calculations and steps were simulated with Microsoft Excel.


Arsenic And Growth Of Amphistegina Gibbosa, Elise Keister Jan 2009

Arsenic And Growth Of Amphistegina Gibbosa, Elise Keister

Undergraduate Journal of Mathematical Modeling: One + Two

A laboratory tested various concentrations of arsenic on the growth of foraminifera and recorded their findings. Upon examination, the plotted probability density function for each of these trials resembled a similar shape. The plots were then characterized in a general model composed of linear segments. Using calculus, statistics such as the expected value, variance and standard deviation were calculated to interpret the collected data. The statistics revealed that arsenic limits the growth of ocean life.


Call Forecasting For Inbound Call Center, Peter Vinje Jan 2009

Call Forecasting For Inbound Call Center, Peter Vinje

Undergraduate Journal of Mathematical Modeling: One + Two

In a scenario of inbound call center customer service, the ability to forecast calls is a key element and advantage. By forecasting the correct number of calls a company can predict staffing needs, meet service level requirements, improve customer satisfaction, and benefit from many other optimizations. This project will show how elementary statistics can be used to predict calls for a specific company, forecast the rate at which calls are increasing/decreasing, and determine if the calls may stop at some point.


Multiple Linear Regression Model Of Visceral Leishmaniasis In Bihar, India, Darren Sheets Jan 2009

Multiple Linear Regression Model Of Visceral Leishmaniasis In Bihar, India, Darren Sheets

Mathematics Theses - Archive

Visceral Leishmaniasis (VL) is one of the world's worst parasitic killers, second only to Malaria, claiming nearly 500,000 lives each year. The disease attacks the spleen, liver, and bone marrow, and if left untreated is nearly always fatal. Whilst the disease is found all around the world, it is primarily prevalent in developing countries, in particular India. The most affected state in India is Bihar, where the disease is endemic. While other research has been conducted with emphasis on the effect of climate variables on the disease incidence rate, this analysis focuses on socio-economic variables such as literacy rate, housing …


A New Method For Non-Rigid Registration Of 3d Images, Mehmet Ali Akinlar Jan 2009

A New Method For Non-Rigid Registration Of 3d Images, Mehmet Ali Akinlar

Mathematics Dissertations - Archive

In this dissertation we present a novel method for the nonrigid registration of 3D images using a well-established mathematical framework mostly known as the deformation based grid generation method. The deformation based grid generation method is able to generate a grid with desired grid density distribution that is free from grid folding. This method gives direct control over the cell size of the adaptive grid and determines the node velocities directly. The adaptive grid system naturally distributes more grids to deprived areas. The positive monitor function disallows grid folding and provides a mean to control the ratio of the areas …


Non-Traditional Socio-Mathematical Norms In Undergraduate Real Analysis, Paul Christian Dawkins Jan 2009

Non-Traditional Socio-Mathematical Norms In Undergraduate Real Analysis, Paul Christian Dawkins

Mathematics Dissertations - Archive

This study builds upon the framework of classroom norms (Cobb, Wood, & Yackel, 1993) and socio-mathematical norms (Cobb & Yackel, 1996) to understand how non-traditional socio-mathematical norms influence student reasoning and transitions to advanced mathematical thinking in undergraduate real analysis. The research involves a qualitative investigation of classroom instruction and interactions, student and instructor interviews, and class exams. The study explores the roles of each norm as the students constructed understanding of advanced mathematics and transitioned to advanced mathematical thinking. I define "non-traditional" according to research accounts of traditional instruction in proof-based mathematics courses and considerations on the culture of …


Large Deviation Principle For Functional Limit Theorems, Adina Oprisan Jan 2009

Large Deviation Principle For Functional Limit Theorems, Adina Oprisan

Mathematics Dissertations - Archive

We study a family of stochastic additive functionals of Markov processes with locally independent increments switched by jump Markov processes in an asymptotic split phase space. Based on an averaging limit theorem, we obtain a large deviation result for this stochastic evolutionary system using a weak convergence approach. Examples, including compound Poisson processes, illustrate cases in which the rate function is calculated in an explicit form.We prove also a large deviation principle for a class of empirical processes associated with additive functionals of Markov processes that were shown to have a martingale decomposition. Functional almost everywhere central limit theorems are …


Logistic Regression With Misclassified Covariates Using Auxiliary Data, Nathan N. Dong Jan 2009

Logistic Regression With Misclassified Covariates Using Auxiliary Data, Nathan N. Dong

Mathematics Dissertations - Archive

When standard regression methods are used, measurement errors cause a bias in parameters estimation. In dealing with discrete covariates, such measurement errors are known as misclassification and the corresponding discrete covariate is said to be misclassified. Even though the collected data may not be fully reliable, it may be possible to collect some sub-data with full precision called auxiliary data and the remaining data called primary data may contain misclassification. In this paper, in order to improve predictions from the primary data with misclassification, we propose a method based on the maximum likelihood approach; by using the prediction with auxiliary …


Optimal Control Approach To Image Registration, Stephen Taiwo Salako Jan 2009

Optimal Control Approach To Image Registration, Stephen Taiwo Salako

Mathematics Dissertations - Archive

The purpose of this dissertation is twofold: To present a new method of orthogonal grid generation and to investigate certain theoretical aspects of the optimal control approach to the image registration problem.In the first part of this dissertation, we will present a variational method of orthogonal grid generation which is based on the deformation method and solving Euler-Lagrange equations. Although the concept of grid generation has been studied extensively, the generation of orthogonal grids is still one of the most challenging problems of the grid generation methods.An orthogonal grid should offer significant advantages in the solution of systems of partial …


Transportation Of Machinery Through A Confined Space, Diana Atwood Jan 2009

Transportation Of Machinery Through A Confined Space, Diana Atwood

Undergraduate Journal of Mathematical Modeling: One + Two

Our goal in this paper is to determine whether a packaging machine of negligible width will fit through a hallway and into a certain room (see page 4 for comments about negligible width). Given the width of the hallway and the room, we apply calculus to find the minimum length available between the two. We determine that the machine will successfully fit into the room.


Buoy Dynamics In Subsurface Zones, Randy Guillen Jan 2009

Buoy Dynamics In Subsurface Zones, Randy Guillen

Undergraduate Journal of Mathematical Modeling: One + Two

The objective of this paper is to find the tension acting on a line that anchors a buoy submerged just beneath the surface of the ocean. Since the problem statement only gives the geometric shapes and dimensions of the buoy, we must use calculus to find its volume and surface area through integration of the volumes and surfaces of revolution formed by the specific parts of the buoy along an axis. The volume and surface area determine the buoyancy force and force of gravity, the two forces acting on the buoy that affect the tension in the line. After calculating …


Reconstruction Of Brooksville Ridge Cave Temperatures From Speleothem Samples, Amor Elder Jan 2009

Reconstruction Of Brooksville Ridge Cave Temperatures From Speleothem Samples, Amor Elder

Undergraduate Journal of Mathematical Modeling: One + Two

A problem was proposed to use an adjusted version of Dorale's speleothem delta function to model the temperature fluctuations in the Brooksville Ridge Cave from the Medieval Warm Period to the present. The temperature values reconstructed by the model can be compared to the known temperature trend during the same selected time period. If the results matched the trend, it indicates that the cave's temperature was the dominant influence. If not, a different variable was the main influence of the cave.

Using δ18O values gathered from a speleothem, past temperatures of the cave were modeled. Results show that …


Calculating Power Of A Co2 Compressor, Jennifer Wedebrock Jan 2009

Calculating Power Of A Co2 Compressor, Jennifer Wedebrock

Undergraduate Journal of Mathematical Modeling: One + Two

In this project the goal is to find the power of a CO2 compressor used in a process of storing CO2 underground. Although the compressor is not 100% efficient and does not exist under ideal conditions, the power can first be calculated as if it were under ideal conditions by calculating its enthalpy and entropy. Residual terms are then added to both the enthalpy and the entropy to account for the behavior of CO2 under non-ideal conditions. Since the sum of the change in entropy under ideal conditions and the residual terms for entropy is zero, a …


A Logistic Approximation To The Cumulative Normal Distribution, Shannon R. Bowling, Mohammad T. Khasawneh, Sittichai Kaewkuekool, Byung R. Cho Jan 2009

A Logistic Approximation To The Cumulative Normal Distribution, Shannon R. Bowling, Mohammad T. Khasawneh, Sittichai Kaewkuekool, Byung R. Cho

Engineering Management & Systems Engineering Faculty Publications

This paper develops a logistic approximation to the cumulative normal distribution. Although the literature contains a vast collection of approximate functions for the normal distribution, they are very complicated, not very accurate, or valid for only a limited range. This paper proposes an enhanced approximate function. When comparing the proposed function to other approximations studied in the literature, it can be observed that the proposed logistic approximation has a simpler functional form and that it gives higher accuracy, with the maximum error of less than 0.00014 for the entire range. This is, to the best of the authors’ knowledge, the …


A Note On The Positive Solutions Of An Inhomogeneous Elliptic Equation On Rn, Yinbin Deng, Yi Li, Fen Yang Jan 2009

A Note On The Positive Solutions Of An Inhomogeneous Elliptic Equation On Rn, Yinbin Deng, Yi Li, Fen Yang

Mathematics and Statistics Faculty Publications

This paper is contributed to the elliptic equation

(0.1) Δu+K(|x|)up+μf(|x|)=0,

where p>1, x∈Rn, n⩾3, and μ⩾0 is a constant. We study the structure of positive radial solutions of (0.1) and obtain the uniqueness of solution decaying faster than r−m at ∞ if μ is small enough under some assumptions on K and f, where m is the slow decay rate.


Periodic Traveling Waves In Sirs Endemic Models, Tong Li, Yi Li, Herbert W. Hethcote Jan 2009

Periodic Traveling Waves In Sirs Endemic Models, Tong Li, Yi Li, Herbert W. Hethcote

Mathematics and Statistics Faculty Publications

Mathematical models are used to determine if infection wave fronts could occur by traveling geographically in a loop around a region or continent. These infection wave fronts arise by Hopf bifurcation for some spatial models for infectious disease transmission with distributed-contacts. Periodic traveling waves are shown to exist for the spatial analog of the SIRS endemic model, in which the temporary immunity is described by a delay, but they do not exist in a similar spatial SIRS endemic model without a delay. Specifically, we found that the ratio of the delay ω in the recovered class and the average infectious …