Improved Annual Average Daily Traffic (AADT) estimation for local roads using parcel-level travel demand modeling

Annual Average Daily Traffic (AADT) is a critical input to many transportation analyses. By definition, AADT is the average 24-hour volume at a highway location over a full year. Traditionally, AADT is estimated using a mix of permanent and temporary traffic counts. Because field collection of traffic counts is expensive, it is usually done for only the major roads, thus leaving most of the local roads without any AADT information. However, AADTs are needed for local roads for many applications. For example, AADTs are used by state Departments of Transportation (DOTs) to calculate the crash rates of all local roads in order to identify the top five percent of hazardous locations for annual reporting to the U.S. DOT. ^ This dissertation develops a new method for estimating AADTs for local roads using travel demand modeling. A major component of the new method involves a parcel-level trip generation model that estimates the trips generated by each parcel. The model uses the tax parcel data together with the trip generation rates and equations provided by the ITE Trip Generation Report. The generated trips are then distributed to existing traffic count sites using a parcel-level trip distribution gravity model. The all-or-nothing assignment method is then used to assign the trips onto the roadway network to estimate the final AADTs. The entire process was implemented in the Cube demand modeling system with extensive spatial data processing using ArcGIS. ^ To evaluate the performance of the new method, data from several study areas in Broward County in Florida were used. The estimated AADTs were compared with those from two existing methods using actual traffic counts as the ground truths. The results show that the new method performs better than both existing methods. One limitation with the new method is that it relies on Cube which limits the number of zones to 32,000. Accordingly, a study area exceeding this limit must be partitioned into smaller areas. Because AADT estimates for roads near the boundary areas were found to be less accurate, further research could examine the best way to partition a study area to minimize the impact.^

Market definition in industrial high-technology markets

This dissertation analyzes how marketers define markets in technology-based industries. One of the most important strategic decisions marketers face is determining the optimal market for their products. Market definition is critical in dynamic high technology markets characterized by high levels of market and technological uncertainty. Building on literature from marketing and related disciplines, this research is the first in-depth study of market definition in industrial markets. Using a national, probability sample stratified by firm size, 1,000 marketing executives in nine industries (automation, biotechnology, computers, medical equipment and instrumentation, pharmaceuticals, photonics, software, subassemblies and components, and telecommunications) were surveyed via a mail questionnaire. A 20.8% net response rate yielding 203 surveys was achieved. The market structure-conduct-performance (SCP) paradigm from industrial organization provided a conceptual basis for testing a causal market definition model via LISREL. A latent exogenous variable (competitive intensity) and four latent endogenous variables (marketing orientation, technological orientation, market definition criteria, and market definition success) were used to develop and test hypothesized relationships among constructs. Research questions relating to market redefinition, market definition characteristics, and internal (within the firm) and external (competitive) market definition were also investigated. Market definition success was found to be positively associated with a marketing orientation and the use of market definition criteria. Technological orientation was not significantly related to market definition success. Customer needs were the key market definition characteristic to high-tech firms (technology, competition, customer groups, and products were also important). Market redefinition based on changing customer needs was the most effective of seven strategies tested. A majority of firms regularly defined their market at the corporate and product-line level within the firm. From a competitive perspective, industry, industry sector, and product-market definitions were used most frequently.

The use of a computer graphic organizer for persuasive composition writing by Hispanic students with specific learning disabilities

Many culturally and linguistically diverse (CLD) students with specific learning disabilities (SLD) struggle with the writing process. Particularly, they have difficulties developing and expanding ideas, organizing and elaborating sentences, and revising and editing their compositions (Graham, Harris, & Larsen, 2001; Myles, 2002). Computer graphic organizers offer a possible solution to assist them in their writing. This study investigated the effects of a computer graphic organizer on the persuasive writing compositions of Hispanic middle school students with SLD. A multiple baseline design across subjects was used to examine its effects on six dependent variables: number of arguments and supporting details, number and percentage of transferred arguments and supporting details, planning time, writing fluency, syntactical maturity (measured by T-units, the shortest grammatical sentence without fragments), and overall organization. Data were collected and analyzed throughout baseline and intervention. Participants were taught persuasive writing and the writing process prior to baseline. During baseline, participants were given a prompt and asked to use paper and pencil to plan their compositions. A computer was used for typing and editing. Intervention required participants to use a computer graphic organizer for planning and then a computer for typing and editing. The planning sheets and written composition were printed and analyzed daily along with the time each participant spent on planning. The use of computer graphic organizers had a positive effect on the planning and persuasive writing compositions. Increases were noted in the number of supporting details planned, percentage of supporting details transferred, planning time, writing fluency, syntactical maturity in number of T-units, and overall organization of the composition. Minimal to negligible increases were noted in the mean number of arguments planned and written. Varying effects were noted in the percent of transferred arguments and there was a decrease in the T-unit mean length. This study extends the limited literature on the effects of computer graphic organizers as a prewriting strategy for Hispanic students with SLD. In order to fully gauge the potential of this intervention, future research should investigate the use of different features of computer graphic organizer programs, its effects with other writing genres, and different populations.

Examining argumentative coherence in essays by undergraduate students of English as a foreign language in Mainland China and their English speaking peers in the United States

I conducted this study to provide insights toward deepening understanding of association between culture and writing by building, assessing, and refining a conceptual model of second language writing. To do this, I examined culture and coherence as well as the relationship between them through a mixed methods research design. Coherence has been an important and complex concept in ESL/EFL writing. I intended to study the concept of coherence in the research context of contrastive rhetoric, comparing the coherence quality in argumentative essays written by undergraduates in Mainland China and their U.S. peers. In order to analyze the complex concept of coherence, I synthesized five linguistic theories of coherence: Halliday and Hasan's cohesion theory, Carroll's theory of coherence, Enkvist's theory of coherence, Topical Structure Analysis, and Toulmin's Model. Based upon the synthesis, 16 variables were generated. Across these 16 variables, Hotelling t-test statistical analysis was conducted to predict differences in argumentative coherence between essays written by two groups of participants. In order to complement the statistical analysis, I conducted 30 interviews of the writers in the studies. Participants' responses were analyzed with open and axial coding. By analyzing the empirical data, I refined the conceptual model by adding more categories and establishing associations among them. The study found that U.S. students made use of more pronominal reference. Chinese students adopted more lexical devices of reiteration and extended paralleling progression. The interview data implied that the difference may be associated with the difference in linguistic features and rhetorical conventions in Chinese and English. As far as Toulmin's Model is concerned, Chinese students scored higher on data than their U.S. peers. According to the interview data, this may be due to the fact that Toulmin's Model, modified as three elements of arguments, have been widely and long taught in Chinese writing instruction while U.S. interview participants said that they were not taught to write essays according to Toulmin's Model. Implications were generated from the process of textual data analysis and the formulation of structural model defining coherence. These implications were aimed at informing writing instruction, assessment, peer-review, and self-revision.

The Use of a Computer Graphic Organizer for Persuasive Composition Writing by Hispanic Students with Specific Learning Disabilities

Many culturally and linguistically diverse (CLD) students with specific learning disabilities (SLD) struggle with the writing process. Particularly, they have difficulties developing and expanding ideas, organizing and elaborating sentences, and revising and editing their compositions (Graham, Harris, & Larsen, 2001; Myles, 2002). Computer graphic organizers offer a possible solution to assist them in their writing. This study investigated the effects of a computer graphic organizer on the persuasive writing compositions of Hispanic middle school students with SLD. A multiple baseline design across subjects was used to examine its effects on six dependent variables: number of arguments and supporting details, number and percentage of transferred arguments and supporting details, planning time, writing fluency, syntactical maturity (measured by T-units, the shortest grammatical sentence without fragments), and overall organization. Data were collected and analyzed throughout baseline and intervention. Participants were taught persuasive writing and the writing process prior to baseline. During baseline, participants were given a prompt and asked to use paper and pencil to plan their compositions. A computer was used for typing and editing. Intervention required participants to use a computer graphic organizer for planning and then a computer for typing and editing. The planning sheets and written composition were printed and analyzed daily along with the time each participant spent on planning. The use of computer graphic organizers had a positive effect on the planning and persuasive writing compositions. Increases were noted in the number of supporting details planned, percentage of supporting details transferred, planning time, writing fluency, syntactical maturity in number of T-units, and overall organization of the composition. Minimal to negligible increases were noted in the mean number of arguments planned and written. Varying effects were noted in the percent of transferred arguments and there was a decrease in the T-unit mean length. This study extends the limited literature on the effects of computer graphic organizers as a prewriting strategy for Hispanic students with SLD. In order to fully gauge the potential of this intervention, future research should investigate the use of different features of computer graphic organizer programs, its effects with other writing genres, and different populations.