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Boosting for Learning From Imbalanced, Multiclass Data Sets
In many real-world applications, it is common to have uneven number of examples among multiple classes. The data imbalance, however, usually complicates the learning process, especially for the minority classes, and results in deteriorated performance. Boosting methods were proposed to handle the imbalance problem. These methods need elongated training time and require diversity among the classifiers of the ensemble to achieve improved performance. Additionally, extending the boosting method to handle multi-class data sets is not straightforward. Examples of applications that suffer from imbalanced multi-class data can be found in face recognition, where tens of classes exist, and in capsule endoscopy, which suffers massive imbalance between the classes. This dissertation introduces RegBoost, a new boosting framework to address the imbalanced, multi-class problems. This method applies a weighted stratified sampling technique and incorporates a regularization term that accommodates multi-class data sets and automatically determines the error bound of each base classifier. The regularization parameter penalizes the classifier when it misclassifies instances that were correctly classified in the previous iteration. The parameter additionally reduces the bias towards majority classes. Experiments are conducted using 12 diverse data sets with moderate to high imbalance ratios. The results demonstrate superior performance of the proposed method compared …
Date:
December 2013
Creator:
Abouelenien, Mohamed
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Finitness and Verb-Raising in Second Language Acquisition of French by Native Speakers of Moroccan Arabic
In this thesis, the three hypotheses on the nature of early L2 acquisition (the Full Transfer/Full Access view of Schwartz and Sprouse (e.g., 1996), the Minimal Trees view of Vainikka and Young-Scholten (e.g., 1996), and the Valueless Features view of Eubank (e.g., 1996)), are discussed. Analysis of the early French production by two native speakers of Moroccan Arabic is done to determine if the L1 grammar is transferred onto the L2 grammar. In particular, the phenomena of verb-raising (as determined by the verb's position vis-a-vis negation) and finiteness are examined. The results of this study indicate that the relevant structures of Moroccan Arabic do not transfer onto the emerging French grammar.
Date:
August 1996
Creator:
Aboutaj, Heidi H. (Heidi Huttar)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Derivatives of 1,4-Naphthoquinone and 1,4-Anthraquinone
The purpose of this investigation was the synthesis of some 1,4-naphthoquinones and 1,4-anthraquinones. It will be shown that some of these substituted quinones exhibit physiological properties.
Date:
August 1959
Creator:
Aboytes, Peter
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Development of a Cost Effective Wireless Sensor System for Indoor Air Quality Monitoring Applications
Poor air quality can greatly affect the public health. Research studies indicate that indoor air can be more polluted than the outdoor air. An indoor air quality monitoring system will help to create an awareness of the quality of air inside which will eventually help in improving it. The objective of this research is to develop a low cost wireless sensor system for indoor air quality monitoring. The major cost reduction of the system is achieved by using low priced sensors. Interface circuits had to be designed to make these sensors more accurate. The system is capable of measuring carbon dioxide, carbon monoxide, ozone, temperature, humidity and volatile organic compounds. The prototype sensor node modules were developed. The sensor nodes were the connected together by Zigbee network. The nodes were developed in such a way that it is compact in size and wireless connection of sensor nodes enable to collect air quality data from multiple locations simultaneously. The collected data was stored in a computer. We employed linear least-square approach for the calibration of each sensor to derive a conversion formula for converting the sensor readings to engineering units. The system was tested with different pollutants and data collected was …
Date:
May 2014
Creator:
Abraham, Sherin
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
An Art Program Utilizing Discarded Materials in the Improvement of Interiors of Homes of Children in a Low Income Group
The problem with which this investigation is concerned is that of planning and carrying out an art program in which a particular group of students in a low income group, by utilizing discarded and inexpensive materials, can create useful and satisfying objects for the improvement of their home interiors.
Date:
January 1960
Creator:
Abram, W. B.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Ultrastructural Changes of Tumor Implants in Mice
The purpose of this investigation was to observe the sequential ultrastructural changes in tumor implants of a well established tumor line in isologous mice.
Date:
January 1970
Creator:
Abrams, Joe A.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Proton-Induced L-shell X-Rays of Pr, Sm, Eu, Gd, and Dy
Characteristic L-shell x rays of the five rare earths Pr, Sm, Eu, Gd, and Dy were studied in this work. The x rays were produced by ionization from 0.3 to 2.0 MeV protons from the 2.0 MV Van de Graaff at North Texas State University. Total L-shell ionization and x-ray production cross sections were measured for Sm and compared to the BEA, CBEA and PWBA theories. Total L-shell ionization cross sections were measured for Pr, Eu, Gd, and Dy and compared to the BEA, CBEA, and PWBA. The CBEA and PWBA fit the samarium data well for both ionization and x-ray production cross sections. The BEA was generally 40 per cent lower than the data. The CBEA and the PWBA also fit the ionization cross section data for Pr, Eu, Gd and Dy, while the BEA was generally 40 per cent lower than the data.
Date:
August 1974
Creator:
Abrath, Frederick G.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Diphenyloxazole Metabolism by Aryl Hydrocarbon Hydroxylase
2,5-Diphenyloxazole (PPO) was tested as a potential alternate inducer for the aryl hydrocarbon hydroxylase (AHH) system. Its apparent lack. of carcinogenicity and toxicity provide a possible system for investigation of enzyme systems related to chemical carcinogenesis without exposure of the researcher to potent carcinogenic compounds. These studies found PPO to be an inducer of AHH in cultured human lymphocytes. When PPO was utilized as a substrate for the AHH assay system, the major metabolites produced were strongly fluorescent. A simple fluorometric assay was developed which employed PPO as the substrate and which measured constitutive activity more efficiently than similar assays using benzo(a)pyrene as the substrate. Quantitation of both basal and induced lymphocyte AHH metabolism of PPO may be applicable to human population studies and may provide a tool to determine possible genetic variables with respect to carcinogen metabolism related to cancer risk.
Date:
December 1976
Creator:
Abreu, Mary E.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Immunofluorescence as a Method for the Rapid Identification of Streptococcus Faecalis in Water
The development and refinement of FA has been adequately investigated with major emphasis on pathogenic microorganisms. The development of this technique has reduced both the time and number of biochemical tests necessary to identify a diversity of organisms. The organisms included are the protozoans, as described by Goldman (1953 and 1957) and by Ingram (1961), viruses, as reported by Liu (1955a) and Burgdorfer and Lackman (1960a), pathogenic bacteria which have been investigated by Moody, Goldman, and Thomason (1956), Moody and Winter (1959), Deason, Falcone, and Harris (1957) and Thomason, Cherry, and Moody (1957). Various fungi have been studied with FA by Kaufman and Brandt (1964), Kaufman and Kaplan (1961 and 1963) and Gordon (1958). Therefore, due to the success of the fluorescent antibody technique in many areas of microbiology in previous investigations, the logical assumption was that immunofluorescence might be incorporated into an efficient system in which a specific organism associated with fecal pollution, such as S. faecalis, could be rapidly identified. Based on this assumption, the feasibility of fluorescent antibody techniques, using S. faecalis was investigated as a means of rapid determination of bacterial pollution in water. Although much progress has been achieved in the study of cytochemical reactions …
Date:
August 1970
Creator:
Abshire, Robert Louis
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Ultrafast Laser Sampling of a Plant Tissue and ion Conductivity Measurement for Investigation of Light Stress Generation Mechanisms
In this study we applied ultra-short laser pulses on a biological sample (Arabidopsis), in order to cut it precisely in a square pattern and subsequently use it for studying stress generation mechanisms. For this purpose, we utilized femtosecond laser pulses at 100 fs pulse width and 80 MHz repetition rate. We took two processing parameters into consideration such as laser power, laser exposure time which is related to the stage speed. Therefore, we were able to find the laser optimum conditions for ablation of biological tissues. The mutant and wildtype (control) obtained from laser cutting with a size of 500 µm × 500 µm were directly transferred (in-situ with laser cutting) into a microfabricated chamber containing ~500 nanoliters deionized water for measuring ion conductivity. The ion conductivity is a signature of cell-death mechanisms caused by various stresses. A light with intensity of 100 µmol was exposed to the samples for 2 hours and 20 minutes as a source of stress. A quantitative electrical analysis with high accuracy was assured by utilizing a microchamber, which enables a measurement in nanoliter volume. We measured the impedance which is reciprocal of conductivity using a lock-in amplifier and a precise current source at frequency …
Date:
August 2010
Creator:
Abtahi, Seyed Ali
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Students' Attitudes toward Educational Gamification in Online Learning Environments
This study explored undergraduate and graduate students' attitudes toward the pleasurability of educational gamification in online learning environments. The study is a sequential explanatory mixed-methods research that investigated students' attitudes quantitatively, then qualitatively. In the quantitative phase, an online survey, the Pleasurable Learning Experiences scale (PLLEXs), was administrated at one of the largest public southwestern universities in the U.S. (N = 119). The qualitative phase involved conducting eight semi-structured interviews with selected participants. The PLLEXs uses a 4-point Likert scale that encompasses 4 subscales: (a) Preferences for Instructions, (b) Preferences for Instructors' Teaching Styles, (c) Preferences for Activities, and (d) Preferences for Learning Effectiveness. A series of analyses of variances (ANOVAs) were used to identify predictors of students' overall attitudes toward educational gamification. The main findings were: (a) students had strong preferences toward educational gamification with Preferences of Instructions rated the highest subscale and Preferences for Activities rated the lowest subscale, (b) major was a statistically significant predictor of students' attitudes toward educational gamification, (c) international students had statistically significant lower preferences toward educational gamification compared with U.S. domestic students, (c) online learning experiences measured by the number of previous online courses and the number of hours spent weekly on …
Date:
May 2019
Creator:
Abu Dawood, Sumayah Mohammadlutfi
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Pressure Controlled Topochemical Polymerization in Two-Dimensional Hybrid Perovskite
Mechanical pressure offers unique control over the energy landscape of chemical reactions, opening up pathways that are inaccessible through conventional thermochemistry. We hypothesize that the reduced dimensionality defines the conformational space of the high-pressure reaction, giving rise to new selectivity that is unavailable in 3D systems. Here, we demonstrate this concept through the pressure-controlled topochemical polymerization of the diacetylene molecule deca‐3,5‐diyn‐1‐amine (DDA) incorporated in the two-dimensional (2D) perovskite [DDA]2PbBr4. Compression at 3 GPa drives the first topochemical polymerization through 1,2 addition, forming a polyene product at room temperature. The reaction is initiated by the mechanical bending of the linear DDA molecule, a mechanism fundamentally different from the 1,4-addition in 3D solids. Importantly, pressure hinders the second 1,2-addition by disfavoring the gauche conformation between the remaining acetylene groups, allowing for the selective formation of polyene versus polyacene products. We characterize the reaction mechanisms and products using spectroscopies (Raman, X-ray photoelectron, ultraviolet-visible), X-ray diffraction and density-functional theory simulations. These results highlight the important role of dimensionality in high-pressure chemistry, and offers a new paradigm for creating low-dimensional functional materials.
Date:
December 2021
Creator:
Abu-Amara, Lama Marwan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Application of Synthetic Peptides as Substrates for Reversible Phosphorylation
Two highly homologous synthetic peptides MLC(3-13) (K-R-A-K-A-K-T-TK-K-R-G) and MLC(5-13) (A-K-A-K-T-T-K-K-R-G) corresponding to the amino terminal amino acid sequence of smooth muscle myosin light chain were utilized as substrates for protein kinase C purified from murine lymphosarcoma tumors to determine the role of the primary amino acid sequence of protein kinase C substrates in defining the lipid (phosphatidyl serine and diacylglycerol) requirements for the activation of the enzyme. Removal of the basic residues lysine and arginine from the amino terminus of MLC(3-13) did not have a significant effect on the Ka value of diacylglycerol. The binding of effector to calcium-protein kinase C appears to be random since binding of one effector did not block the binding of the other.
Date:
August 1992
Creator:
Abukhalaf, Imad Kazem
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
An Analysis of Marketing in Saudi Arabia and American Marketing Executives' Knowledge About the Saudi Arabian Market
The problem of the present study was to describe and analyze marketing in Saudi Arabia and American marketing executives' knowledge about the Saudi market. The purposes of the study were twofold: (1) to describe and analyze marketing in Saudi Arabia and (2) to determine what American marketing executives know about the Saudi Arabian market. This study employed both primary and secondary data. For the analysis of marketing in Saudi arabia, primarily secondary sources were used from the available literature. For the analysis of American marketing executives' knowledge about the Saudi Arabian market, primary sources were used in the form of American marketers' responses to a mailed questionnaire.
Date:
December 1981
Creator:
Abunabaa, Abdelaziz M.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Corporate Christians and Terrible Turks: Economics, Aesthetics, and the Representation of Empire in the Early British Travel Narrative, 1630 - 1780
This dissertation examines the evolution of the early English travel narrative as it relates to the development and application of mercantilist economic practices, theories of aesthetic representation, and discourses of gender and narrative authority. I attempt to redress an imbalance in critical work on pre-colonialism and colonialism, which has tended to focus either on the Renaissance, as exemplified by the works of critics such as Stephen Greenblatt and John Gillies, or on the later eighteenth and early nineteenth centuries, as in the work of scholars such as Srinivas Aravamudan and Edward Said. This critical gap has left early travel narratives by Sir Francis Moore, Jonathan Harris, Penelope Aubin, and others largely neglected. These early writers, I argue, adapted the conventions of the travel narrative while relying on the authority of contemporary commercial practices. The early English travelers modified contemporary conventions of aesthetic representation by formulating their descriptions of non-European cultures in terms of the economic and political conventions and rivalries of the early eighteenth century. Early English travel literature, I demonstrate, functioned as a politically motivated medium that served both as a marker of authenticity, justifying the colonial and imperial ventures that would flourish in the nineteenth century, and as …
Date:
December 2003
Creator:
Abunasser, Rima Jamil
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Studies on the Mechanism of Protection by Carotenoids Against Photodynamic Killing in Curtobacterium Flaccumfaciens Pathover Poinsettiae
The mechanism of protection by carotenoids against photodynamic killing in Curtobacterium flaccumfaciens pathover poinsettiae (C. poinsettiae) was studied using pigment mutants isolated by treatment with nitrosoguanidine and DNA gyrase inhibitors. Growth rates, pigment composition, pigment levels and the ultrastructure of the wild-type streptomycin resistant strain of G. poinsettiae (wt-str) and all mutants were compared. One mutant, NTG-1, lacked colored carotenoids, and another, NTG-2, was a slow growing mutant containing low levels (14%) of wild-type carotenoid pigments. Except for NTG-1, the other pigment mutants had different proportions of the same pigments found in the wild type as determined by high performance liquid chromatography (HPLC). Only NTG-2 was morphologically distinct at the ultrastructural level.
Date:
August 1992
Creator:
Abusada, Gabi M. (Gabi Michael)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Exploratory Analysis of Social E-health Behavior
Extant literature has documented well that people seek health information via the internet as patients and consumers. Much less, however, is known about interaction and creation behaviors in the development of new online health information and knowledge. More specifically, generalizable sociodemographic data on who engages in this online health behavior via social media is lacking in the sociological literature. The term “social e-health” is introduced to emphasize the difference between seeking behaviors and interaction and creation behaviors. A 2010 dataset of a large nationally representative and randomly sampled telephone survey made freely available from the Pew Research Center is used to examine social e-health behavior according to respondents’ sociodemographics. The dependent variable of social e-health behavior is measured by 13 survey questions from the survey. Gender, race, ethnicity, age, education, and income are used as independent variables. Logistic regression analysis was used to determine the odds of engagement in social e-health behavior based on the sociodemographic predictors. The social determinants of health and digital divide frameworks are used to help explain why socioeconomic variances exist in social e-health behavior. The findings of the current study suggest that predictable sociodemographic patterns along the dimensions of gender, race, age, education, and income …
Date:
May 2014
Creator:
Acadia, Spencer
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Cooperative Strategy and Sources of Knowledge Integration Capability and Innovation: A Relational View
Faced with the challenges to addressing the novelties of the changing business environments (e.g., new customer requirement, changes in customers taste and preferences, the introduction of new products or services by competitors), organizations seek to build collaboration among their employees who possess complementary knowledge. Integrating complementary knowledge enhances employees' ability to address environmental challenges and foster innovation. Despite the importance of knowledge integration for innovation, integration of such knowledge becomes difficult when employees lack a shared understanding of knowledge, and when the knowledge is newly generated. Because new knowledge is tacit in nature and highly personal to a particular individual, it is difficult to articulate, making knowledge integration (KI) an arduous task. Lack of shared understanding, the presence of new knowledge, and lack of common interests in employees creates three types of knowledge boundaries – syntactic (information processing) boundaries, semantic (interpretive) boundaries, and pragmatic (political) boundaries. The presence of knowledge boundaries makes it difficult for employees to share and access their knowledge with each other. To overcome the challenges related to the knowledge boundaries, employees use boundary-spanning objects, which are common lexicons, common meaning, and common interests, to share and access their knowledge across the boundaries. Although prior studies have …
Date:
August 2016
Creator:
Acharya, Chandan
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Love Attitudes and Marital Adjustment Through Five Stages of the Marital Life-Cycle in Protestant Nigerian Society
This study examined the relationship between love attitude and marital adjustment across five stages of the marital life-cycle in Nigerian society. The subjects for this study were 202 volunteers from six protestant churches representing six cities in the southern part of Nigeria. An average of 20 couples were representatives of each of the five marital life-cycles. Each of the subjects completed the Love Attitude Inventory (LAI), and the Marital Adjustment Test (short form) (MAT). Wilk's multivariate analysis revealed no significant differences between husbands' and wives' love attitude and marital adjustment across the five stages of the marital life cycle. Multivariate analysis split-plot 5.2 with repeated measures revealed no significant difference for the total sample among the groups, but indicated a significant difference between love attitude and marital adjustment for the total sample using sex as a factor. A univariate test of the MAT and LAI indicated that the MAT accounted for the difference. A canonical correlation indicated a significant positive relationship between husbands1 and wives' marital adjustment and love attitude within each of the five groups. The findings suggest that husbands and wives included in this study have a good understanding of their roles in the marriage relationship and that …
Date:
December 1988
Creator:
Acho, Onyebuchi S. (Onyebuchi Sunday)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Cognitive Congruence and Interactional Behavior of Cotherapists
Proponents of the use of cotherapists have stressed the importance of compatibility for effective cotherapy teams; however, the nature of compatibility has received little attention in experimental literature. This study investigated the nature of an effective cotherapy relationship through use of concepts espoused by George Kelly in his personal construct theory. Based on the results of the study, it was recommended that cotherapists be paired on the basis of their cognitive congruence. It was further proposed that cotherapists, especially those low in content congruence, allow themselves sufficient time for case discussion prior to and following their therapy sessions.
Date:
August 1980
Creator:
Achterberg, Gloria Jeanne
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Haves, Halves, and Have-Nots: School Libraries and Student Achievement in California
This descriptive, non-experimental study examines the strength of the relationship between California school library media programs and student achievement, using data from California criterion-referenced state-wide tests, publically available school and community demographic data, and a state survey of school library programs. Results indicate a substantial discrepancy in library staffing levels from the elementary grades through the high schools. Nevertheless, statistically significant correlations were found between certificated staffing levels and student achievement at each grade. Significant correlations persisted at the elementary and middle school when controlling for five of six school and community variables, and at the high school when controlling for all six of those variables. Bivariate correlations between total staffing and student achievement were significant at both the middle school and high school level when controlling for all school and community variables. Generally, the strength of the correlations between both certificated and total staffing tended to increase with grade level; at the high school level, correlations were among the strongest reported in any statewide study to date. There was a significant positive relationship between a majority of the 21 library services regularly provided and student achievement at all levels. Total library services were significantly related to student achievement at …
Date:
December 2008
Creator:
Achterman, Douglas L.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Critical Analysis of the Trio in E Flat Major, Opus 40, by Brahms
It is the purpose of this study to aide in the understanding of the Horn Trio through a biographical sketch of Brahms, a discussion of his use and characterization of the instruments, and the thematic, harmonic, and structural organization of the trio.
Date:
August 1948
Creator:
Acker, Mary March
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Victorian Ideology and British Children's Literature 1830-1914
This dissertation shows the ideas of Victorian England, 1850-1914, as reflected in Victorian children's literature. To establish the validity of studying children's literature as a guide to the Victorian age, it was necessary first to show that children's literature in those years reflected and promoted adult ideals. Sources used include not only works by established authors but also children's periodicals and transient writings like "penny dreadfuls." There are four background chapters: an introduction, a brief social history, a history of publishing for children, and an examination of Victorian children's authors. Six chapters examine Victorian children's literature in relation to specific historical themes: class structure; the social problems of poverty; temperance; morality, manners, religion, and science; patriotism; and natives, slavery, and missionaries in relation to imperialism. Many findings support accepted historical theories. Attitudes on social class revealed definite class separations, mobility, and obligations. Stories on poverty and child labor show Victorian concern, but suggest few solutions other than charity. Literary items on religion and morality reflect a dominance of evangelical values. There was a morality separate from religion, and it was not threatened by the new developing science; indeed, the materials examined reveal how Victorians tried to reconcile the new science …
Date:
December 1984
Creator:
Ackerman, Ann Trugman
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
A Study to Determine the Relationship of Versatile Behavior to Individual Demographics, Job Characteristics, Organizational Climate Performance Feedback and Job Satisfaction
The behavioral characteristics of leaders have been subjects of study for centuries. The scope of these studies has grown to encompass task analysis, follower needs and situational requirements. Current leadership theories consistently recognize the need for a successful leader to adjust behavior to meet the needs of the task, followers and situation. The problem of this research is to define this ability to modify one's behavior, measure it and test its relationship to demographic and job characteristics. The purpose of this study is to evaluate the correlation of individuals" ability to modify their behavior to job function, hierarchy, climate, feedback, satisfaction and their demographic characteristics. The hypotheses held that high ability to modify behavior would correlate positively with job characteristics, climate, feedback and satisfaction and show no correlation to individual demographics. Data were collected through the administration of three research instruments to 138 managers of three business firms. The instruments were the Participant Data Form providing job and demographic characteristics, Descriptive Adjective Questionnaire measuring an individual ability to modify behavior, and Climate and Satisfaction Evaluation Index measuring climate, feedback and satisfaction. Perason's correlation coefficients were calculated to identify possible relationship between the manager's ability to modify behavior, called versatility, and …
Date:
May 1988
Creator:
Ackerman, Raymond L. (Ramond Lorens)
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library