Digital Commons Network^™

A Study Of The Knowledge Structure Of Expert, Intermediate, And Novice Subjects In The Domain Of Physics, Jennifer L. Discenna

Dissertations

The objective of this research was to investigate the knowledge structure in physics by describing the knowledge of experts, intermediates, and novices. A review of the literature on expertise, physics knowledge, and conceptual structure provided two competing representations of physics knowledge: one defined as a hierarchy of models arranged from general to specific models, the second defined by theories which link knowledge together.

In order to investigate the two representations described above, a reiterative categorization task was employed. This task resulted in a hierarchical sort with larger piles at the top of the hierarchy and smaller piles at the bottom …

Surface Models Of Finite Geometries, Ramon Manuel Figueroa-Centeno

Dissertations

The standard non-Euclidean geometries, hyperbolic geometry and elliptical geometry, both arise by negating the parallel postulate of Euclid. Both these geometries share with Euclidean geometries an infinitude of points and lines. But also possible are many finite geometries. Among these are the class of projective geometries PG(m,q) of projective dimension m (m > 2) and the k-configurations. These mathematical objects, although primarily geometric in nature, provide related structures of combinatorial interest: block designs. These have applications in scheduling problems and the design of experiments for statistical analysis. Recently, A. T. White has added a topological flavor to the study …

Perturbed Hamiltonian System Of Two Parameters With Several Turning Points, Myeong Joon Ann

Dissertations

No abstract provided.

Preparation For The Gre, Corina Groeger

Dissertations

The present research consisted of two empirical studies and a literature review. The first study was a systematic replication of the studies by Miller, Goodyear-Orwart, and Malott (1996) and Vunovich and Malott (1997). Fourteen undergraduate students and one graduate student participated in four intensive, extensive, structured Graduate Record Examination (GRE) preparation courses that met for seven weeks and lasted between 99 and 140 hours. The courses offered a monetary reward for students who met a minimum of 92% for attendance and participation during the course. The results of this study showed statistically significant mean improvements of 145 points for the …

Electron Emission Following The Interaction Of Slow Highly Charged Ions With Solids, Joseph W. Mcdonald

Dissertations

The interaction of highly-charged ions with surfaces involves many excitation processes of the surface atoms and the bulk material. One such process, the emission of electrons from surfaces due to the potential energy of the incident ions has been studied. The experimental results presented here confirm that the majority of electrons emitted as a result of highly-charged ions interacting with a solid surface have energies of about 20 eV. Auger processes contribute a smaller fraction of the total emitted electrons with increasing Z o f the projectile. This contribution to the total electron emission yield is found to be less …

The Effects Of Writing Assignments On Second-Semester Calculus Students' Understanding Of The Limit Concept, Melanie A. Wahlberg

Dissertations

The purpose of this study was to determine the impact of writing assignments on second-semester calculus students’ understanding of the limit concept, using both qualitative and quantitative techniques. The study involved two sections of second semester calculus (n = 37, 34) at Western Michigan University during the fall semester of 1997.

The treatment group completed six writing tasks focusing on the mathematical concept of limit. These conceptually-oriented writing assignments replaced some of the problem sets that the instructor would have normally assigned. The control group did not engage in writing tasks but handed in problem sets more frequently than the …

Fostering Reflective Thinking In First-Semester Calculus Students, Pamela Crawford

Dissertations

This study focuses on the fostering of reflective thinking in students in a reform calculus course through completion of homework assignments incorporating reflective tasks, and the effect of these assignments on student understandings of calculus and conceptions of mathematics. The study, conducted in Fall 1997, involved two sections of first-semester calculus at a large midwestern university and used quantitative (n = 25, 18) and qualitative (n = 7) techniques.

Homework assignments incorporating reflective tasks included asking students to compare and contrast textbook ideas; to write about how obstacles were overcome as they attempted exercises; to develop concept maps organizing and …

Analytical And Experimental Study Of Investment Casting With Laser Stereolithography Models, Wen-Long Yao

Dissertations

This dissertation presents an analytical and experimental investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography (SLA) patterns. Included in the consideration are the cracking temperature of the ceramic shell, the web link buckling temperature, and the glass transition temperature of the epoxy resin. The hypothesis is that shell cracking will occur when the cracking temperature is lower than the glass transition temperature and the web buckling temperature.

An analytical and experimental study has been conducted, with the cross-sectional area, the span length of the web structure, and the shell thickness being …

A Combined Simulated Annealing And Tabu Search Strategy To Solve Network Design Problem With Two Classes Of Users, Qifeng Zeng

Dissertations

A methodology to solve a transportation network design problem (TCNDP) with two classes of users (passenger cars and trucks) is developed. Given an existing highway system, with a capital investment budget constraint, the methodology selects the best links to be expanded by an extra lane by considering one of three types of traffic operations: exclusive for passenger cars, exclusive for trucks, and for both passenger cars and trucks such that the network total user equilibrium (UE) travel time is minimized.

The problem is formulated as an NP-hard combinatorial nonlinear integer programming problem. The classical branch and bound methodology for the …

Space-Time Reduced Rank Methods And Cfar Signal Detection Algorithms With Applications To Hprf Radar, Tareq F. Ayoub

Dissertations

In radar applications, the statistical properties (covariance matrix) of the interference are typically unknown a priori and are estimated from a dataset with limited sample support. Often, the limited sample support leads to numerically ill-conditioned radar detectors. Under such circumstances, classical interference cancellation methods such as sample matrix inversion (SMI) do not perform satisfactorily. In these cases, innovative reduced-rank space-time adaptive processing (STAP) techniques outperform full-rank techniques. The high pulse repetition frequency (HPRF) radar problem is analyzed and it is shown that it is in the class of adaptive radar with limited sample support. Reduced-rank methods are studied for the …

Removal Of Volatile Organic Compound (Voc) Vapors In Biotrickling Filters : Process Modeling And Validation With Chlorinated Aromatic Compounds, Christos J. Mpanias

Dissertations

This study dealt with the removal of vapors of volatile organic compounds from airstreams in biotrickling filters (BTFs). A detailed general model was developed for describing the process under steady-state conditions. The model accounts for mass transfer between phases (air, liquid, biofilm) and biodegradation of pollutants in the biofilm. It also accounts for potential kinetic interactions among pollutants as well as potential process limitations by oxygen availability.

The general model was experimentally validated using mono-chlorobenzene (m-CB) and ortho-dichlorobenzene (o-DCB) as model compounds either alone or in mixture with each other. Before BTF experiments were undertaken, a systematic kinetic study was …

Robust Fuzzyclustering For Object Recognition And Classification Of Relational Data, Sumit Sen

Dissertations

Prototype based fuzzy clustering algorithms have unique ability to partition the data while detecting multiple clusters simultaneously. However since real data is often contaminated with noise, the clustering methods need to be made robust to be useful in practice. This dissertation focuses on robust detection of multiple clusters from noisy range images for object recognition. Dave's noise clustering (NC) method has been shown to make prototype-based fuzzy clustering techniques robust. In this work, NC is generalized and the new NC membership is shown to be a product of fuzzy c-means (FCM) membership and robust M-estimator weight (or possibilistic membership). Thus …

The Intelligent Browser For Texpros, Chih-Ying Wang

Dissertations

Browsing is a technique, which helps users to formulate their query and retrieve information in the information retrieval system. This technique provides users with capabilities of understanding their information needs and gaining system knowledge during the course of the browsing and thus it eases the users' burden when issuing queries. The basic components of the browser provides an underlying structure which allows users to navigate and a browsing process controller which provides users with the needed assistance during each browsing session.

In this dissertation, a new infrastructure (OP-Net), transformed from the existing object network is proposed. Each object in the …

Modelling Of In-Situ Bioremediation With Emphasis On Inhibitory Kinetics And Biomass Growth, Dilip Kumar Mandal

Dissertations

This thesis was motivated by the need for better engineering tools to predict the extent of contaminant plume migration in the saturated zone. The principal result was a mathematical model analogous to a catalytic packed-bed reactor, in which the subsurface was considered to be composed (conceptually) of soil aggregates (the "catalyst" particles, in which biodegradation, diffusion, and sorption take place), and a mobile phase (groundwater) passing around the aggregates, in which convection, axial diffusion, and mass transfer from the aggregates take place.

The modelling emphasis was on a more detailed exposition of the biokinetics of the system (including an inhibitory …

Knowledge-Based Document Filing For Texpros, Xien Fan

Dissertations

This dissertation presents a knowledge-based document filing system for TEXPROS. The requirements of a. personal document processing system are investigated. In order for the system to be used in various application domains, a flexible, dynamic modeling approach is employed by getting the user involved in document modeling. The office documents are described using a dual-model which consists of a document type hierarchy and a folder organization. The document type hierarchy is used to capture the layout, logical and conceptual structures of documents. The folder organization, which is defined by the user, emulates the real world structure for organizing and storing …

A Paleoclimatic Study Of The Midwestern United States From The Stable Isotope Records In Lake Sediments, Norman Alan Lovan

Dissertations

No abstract provided.

The Role Of Ethnicity Among International Students In Adjustment To Acculturative Stress, Mohd. Tajudin Hj Ninggal

Dissertations

This study examined whether there were differences in six acculturative stress themes among three Malaysian ethnic groups who were enrolled at Western Michigan University during the Fall, 1997 semester. The study also investigated whether the following demographic attributes: (a) gender, (b) academic major, (c) financial sponsorship, (d) family socioeconomic status, (e) type of residential setting, and (f) scores on the Test of English as a Foreign Language (TOEFL) affected Malaysian students in relation to the six acculturative stress themes: (1) Perceived Discrimination, (2) Homesickness, (3) Perceived Hate, (4) Fear, (5) Culture Shock, and (6) Guilt.

A total of 138 respondents …

Groundwater Hydraulics And Slope Stability Analysis: Elements For Prediction Of Shoreline Recession, William W. Montgomery

Dissertations

Studies documenting the roles that geologic materials and groundwater play in Great Lakes bluff recession are rare. This study reports findings concerning relationships between bluff lithology, bluff hydrology, and bluff recession along a 10-mile stretch of eastern Lake Michigan shoreline in heterogeneous Pleistocene deposes. According to a newly-developed, field-tested, GIS-based methodology, bluffs in the study area can be characterized lithologically as sand, clay, or mixed sand/clay, and can be characterized hydrologically as exhibiting either high head or low head.

Geotechnical analysis indicates that Atterberg limits, index properties, consolidation state, and drainage conditions affect the shear strength of bluff materials. Silty …

Implications Of Changing To 4 By 4 Semester Block Scheduling For Secondary Students With Learning Disabilities, Sandra Kay Wayne

Dissertations

The purpose of this study was to investigate the impact of changing from a traditional schedule to a block schedule on selected school-related behaviors and measures of secondary students with learning disabilities and their regular education teachers. Areas of impact that were addressed included school performance measures of student success rates, attendance rates, and discipline referrals as well as affective measures of levels of students' active engagement in learning activities, the variety of teaching and learning modes used, and the amount of individualized teacher attention given to students.

The research population consisted of six high schools in south and central …

An Analysis Of Fecal Coliform Bacteria As A Water Quality Indicator, Janet Heyl Vail

Dissertations

The focus of this study is to assess the efficacy of fecal coliform bacteria as a microbiological water quality indicator. The scientific and educational context of fecal coliform bacteria is explored through analysis of large sets of water quality data, focused field monitoring projects, and review of commonly used resources for school-based and volunteer water-related studies. Analyzed data sets include long term sampling (10 years), multiple sites, daily samples, storm event samples, and other parameters monitored in parallel with bacteria. Special attention is given to data sets from Kent County, Michigan. A background reference site in Michigan unimpacted by humans …

Orthogonal Transmultiplexers : Extensions To Digital Subscriber Line (Dsl) Communications, Xueming Lin

Dissertations

An orthogonal transmultiplexer which unifies multirate filter bank theory and communications theory is investigated in this dissertation. Various extensions of the orthogonal transmultiplexer techniques have been made for digital subscriber line communication applications.

It is shown that the theoretical performance bounds of single carrier modulation based transceivers and multicarrier modulation based transceivers are the same under the same operational conditions. Single carrier based transceiver systems such as Quadrature Amplitude Modulation (QAM) and Carrierless Amplitude and Phase (CAP) modulation scheme, multicarrier based transceiver systems such as Orthogonal Frequency Division Multiplexing (OFDM) or Discrete Multi Tone (DMT) and Discrete Subband (Wavelet) Multicarrier …

A Model For Travel Mode Switching, Lei Cao

Dissertations

Transportation policy research assesses the effect of policy changes such as the imposition of a parking charge or the augmentation of passenger rail service, on individual travel behavior. Over the last few decades, Conditional Lo it Model has been strongly advocated among discrete choice models for transportation policy study due to its ease of estimation and realistic outcomes.

This dissertation analyzes the necessity of the entry of constraints in the indirect utility function. These functions are used in discrete choice models and form the basis for travel demand modeling. This dissertation proposes a hypothesis that the explicit entry of constraints …

Biodegradation Of Pah Contaminated Soil And Sludge Using Non-Ionic Surfactants, Seema Narula

Dissertations

Polycyclic aromatic hydrocarbons (PAHs) are one of the most prevalent environmental pollutants contaminating a large number of industrial and Superfund sites. Low solubility and sorption to solid surfaces limit biodegradation rates of PAHs in the environment. Bioremediation of these compounds have been previously tested with partial success. In the present study, aerobic biodegradation of three PAHs (fluorene, phenanthrene, and pyrene) has been studied in shaker flasks, batch fermenter, and bioslurry reactor, in the presence of non-ionic surfactants. A mixed bacterial culture derived from both a refinery sludge and an activated sludge was used as the seed population in the degradation …

Flag : The Fault-Line Analytic Graph And Fingerprint Classification, Ching-Yu Huang

Dissertations

Fingerprints can be classified into millions of groups by quantitative measurements of their new representations - Fault-Line Analytic Graphs (FLAG), which describe the relationship between ridge flows and singular points. This new model is highly mathematical, therefore, human interpretation can be reduced to a minimum and the time of identification can be significantly reduced.

There are some well known features on fingerprints such as singular points, cores and deltas, which are global features which characterize the fingerprint pattern class, and minutiae which are the local features which characterize an individual fingerprint image. Singular points are more important than minutiae when …

Decentralized Reliable Control For Large-Scale Lti Systems, Zhengfang Chen

Dissertations

Reliable control concerns the ability of closed loop system to maintain stability and regulation properties during arbitrary sensor, controller, and actuator failure. Reliable control research has been an active research topic for more than 10 years.

Recent approach for reliable control includes the H∞ method, the algebraic factorization design, and the robust servomechanism control. These methods have been surveyed and discussed in this thesis with the robust servomechanism control methodology serving as the basis of the research development of this work.

In this thesis, the reliable control for large-scale, multi-input/output linear system is considered. Two concepts of reliable control …

Numerical Study Of Three-Dimensional Free Convection From Semi-Enclosed Geometry And Discontinuous Heat Sources, Aklilu T.G. Giorges

Dissertations

Three-dimensional natural convection from three-by-three array of isoflux heat sources mounted on one vertical wall of semi-enclosed region has been numerically investigated. Detailed thermal information of this important engineering configuration is currently not available. The major objective of this study was to obtain this needed thermal and velocity information.

The semi-enclosed geometry can be viewed as a thin rectangular region with four closed and two open sides. The open surfaces are located at the top and adjacent side. For the fluid air, Pr = 0.71, the study covered a heat flux based Rayleigh number (Ra) range of (10² ≤ …

Effects Of Surfactants And Fenton's Reagents On Extraction And Destruction Of Phenanthrene In Spiked Sand, Ming-Chin Chang

Dissertations

In this study, surfactants and Fenton's reagents (Fe(II) and H₂0₂) ere proposed to solve contaminated site problems in situ on a lab scale. Phenanthrene is a simple PAHs (polynuclear aromatic hydrocarbons). The phenanthrene spiked ottawa sand simulated contaminated soil. HPLC was used for phenanthrene analysis because it provided excellent separation and no interference. Six surfactants (including nonionic and ionic) were tested. The operating conditions were optimized based on process and economic considerations such as reaction time, mixing speed, concentrations of surfactants and concentrations of Fenton's reagents. Surfactants could effectively dissolve phenanthrene from the spiked sand. In …

An Analysis Of The Gallup Poll Data Regarding The Public's Assessment Of The Public Schools From 1986-1995, Biancalana Venette Meucci

Dissertations

No abstract provided.

Biophysical Studies Of The Spectrin Sequence Motif, Denise M. Lusitani

Dissertations

No abstract provided.

Variables That Discriminate Between Persisting And Nonpersisting, First-Year Undergraduate Students In An Open-Admissions, Multicampus, Commuter College System, Jeffrey David Hines

Dissertations

Problem. Most new undergraduate students begin college with the highest hope of finishing their educational programs. Unfortunately, a large number of students drop out prior to graduation. This is particularly true of nontraditional students who attend nonresidential commuter colleges. This study investigates the differences between nontraditional commuter students who persist through to completion, and those who do not.

Method. A total of 436 Davenport College students, 65 males and 371 females, was surveyed for this study. They were full or part-time, certificate, diploma, or degree-seeking students at one of five Davenport campuses: South Bend and Merrillville, Indiana; Grand Rapids, …