Showing papers by "University of North Carolina at Charlotte published in 1997"

Adaptive evolutionary planner/navigator for mobile robots

Abstract: Based on evolutionary computation (EC) concepts, we developed an adaptive evolutionary planner/navigator (EP/N) as a novel approach to path planning and navigation. The EP/N is characterized by generality, flexibility, and adaptability. It unifies off-line planning and online planning/navigation processes in the same evolutionary algorithm which 1) accommodates different optimization criteria and changes in these criteria, 2) incorporates various types of problem-specific domain knowledge, and 3) enables good tradeoffs among near-optimality of paths, high planning efficiency, and effective handling of unknown obstacles. More importantly, the EP/N can self-tune its performance for different task environments and changes in such environments, mostly through adapting probabilities of its operators and adjusting paths constantly, even during a robot's motion toward the goal.

Stuck in the Model Trap: The Effects of Beautiful Models in Ads on Female Pre-Adolescents and Adolescents

Abstract: One of advertising's “unintended effects” is the impact highly attractive models may have on female pre-adolescents and adolescents. Using social comparison theory as a framework, the authors propose that young girls compare their physical attractiveness with that of advertising models and, subsequently, their self-perceptions and self-esteem may be affected, depending on the motive for social comparison. They report a study with a mixed-model design in which motive was manipulated. Girls in grades four, six, and eight participated. The results suggest that motive is important, as support was found for all hypotheses. However, the support was not consistent across all grades or for all dependent variables. The authors consider possible reasons for the inconsistency and discuss the implications of the findings for advertisers and educators.

Generality, Continuity, and Change in Offending

Abstract: A number of criminological theories make either implicit or explicit predictions about the empirical relationship between prior and future offending behavior. Some argue that time-stable characteristics such as criminal propensity should account for any positive correlation between past and future criminal behavior for all individuals. Others contend that the positive association between offending behavior at different points in time are partly causal and partly spurious. Still others anticipate that different patterns will emerge for different groups (distinguished by their ciminal propensity) of individuals. Using a longitudinal data set comprised of 848 training school releasees, we test various hypotheses emanating from these different theoretical perspectives. The results indicate that (1) both stability and change have causal implications for one's offending behavior and (2) with but one exception, these effects do not vary between high and low criminal propensity groups.

Duality and singular continuous spectrum in the almost Mathieu equation

Abstract: q2 a P--E~ I --+ 0 (1.2) qn I as n ~ c ~ . Then for a.e. 8, hA=2,a,o has purely singular continuous spectrum. Remarks. (1) (1.2) is used because for such a, Last [22] has proven that the spectrum, a~,~, of h~,~,e (which is 0-independent [5]) has la2,al=0 (where I" I denotes Lebesgue measure). Our proof is such that for any other a with la~=2,~ I=0 (presumably all irrational a), one has that hA=2,a,e has purely singular continuous spectrum for a.e.O.

Wavelet sets in ℝ n

Abstract: A congruency theorem is proven for an ordered pair of groups of homeomorphisms of a metric space satisfying an abstract dilation-translation relationship. A corollary is the existence of wavelet sets, and hence of single-function wavelets, for arbitrary expansive matrix dilations on L 2 (ℝ n). Moreover, for any expansive matrix dilation, it is proven that there are sufficiently many wavelet sets to generate the Borel structure ofℝ n.

Neuropsychology of chronic fatigue syndrome: A critical review

Abstract: This article provides a comprehensive and critical review of the neuropsychological and related literature on chronic fatigue syndrome (CFS) Despite the methodological limitations observed in several studies, some consistent findings are noted The most consistently documented neuropsychological impairments are in the areas of complex information processing speed and efficiency General intellectual abilities and higher order cognitive skills are intact Emotional factors influence subjective report of cognitive difficulty, whereas their effect on objective performance remains uncertain Although the neuropathological processes underlying cognitive dysfunction in CFS are not yet known, preliminary evidence suggests the involvement of cerebral white matter Directions for future research are outlined

Fiberoptic interferometer and associated method for analyzing tissue

Abstract: The fiberoptic interferometer includes a broadband light source which is selected to illuminate tissue of predetermined organ with light having a wavelength within a predetermined range of wavelengths. Within the predetermined range of wavelengths, the attenuation characteristics of tissue of the predetermined organ define a region of minimum attenuation upon illumination with light having a first wavelength. As a result, the fiberoptic interferometer can precisely determine the optical properties of the tissue and can therefore identify the tissue by comparing the interferometric signal produced upon illumination of the tissue sample with predetermined interferometric signals corresponding to illumination of different types of tissue of the predetermined organ with light having the first wavelength. The fiberoptic interferometer can also include a light source which includes wavelength selection means for controllably selecting the predetermined wavelength of light emitted by the light source. Thus, the optical properties of the tissue can be analyzed at the different wavelengths emitted by the light source to individually determine the optimum wavelength of light for subsequent treatment of the tissue.

An Evaluation of Transition Components of Individualized Education Programs

Abstract: This study evaluated the transition component of the individualized education programs (IEPs) of 94 high school students between the ages of 18 and 21—students with learning disabilities, mild mental retardation, moderate mental retardation, and emotional/behavioral disorders. The study examined the format of the transition component document, compliance with the mandates of the Individuals with Disabilities Education Act (IDEA), and reflections of best practices, as well as the differences in these aspects of IEP transition components among disability groups. Results indicated that although the majority of the transition components complied with IDEA's mandate, they lacked many of the essential elements reflective of best practices in transition.

Localized Classical Waves Created by Defects

Abstract: We study acoustic and electromagnetic waves in a periodic medium (or any other background medium with a spectral gap) disturbed by a single defect, i.e., a local disturbance analogous to a well potential in solid state physics. We show that defects do not change the essential spectrum of the associated nonnegative operators and can only create isolated eigenvalues of finite multiplicity in a gap of the periodic medium, with the eigenmodes decaying exponentially. We give a constructive and simple description of defects in acoustic and dielectric media, including a simple condition on the parameters of the medium and of the defect, which ensures the rise of a localized eigenmode with the corresponding eigenvalue in a specified subinterval of the given gap of the periodic medium.

Double standards in just earnings for male and female workers

Abstract: When observers judge the amount of a reward they consider just for target recipients, they may treat male and female recipients differently, and this gender-based double standard may itself differ by the observer's own gender. In this paper we develop a framework that enables quantitative assessment of multiple standards as well as of the mechanisms by which they operate. The framework also makes it possible to test for differences in multiple standards across different subsets of respondents; and it is applicable to questions of multiple standards in both justice judgments and allocation decisions. To illustrate the framework, we examine a special case of multiple standards-gender-based double standards-and we focus on judgments of just earnings, using data collected by Rossi's factorial survey method. We conduct two main sets of analyses, the first focusing on the double standard and the second on the mechanisms by which the double standard operates. In the first set we estimate the just gender wage gap, in the eyes of male and female observers separately, establishing the existence and direction of the just gender wage gap and quantifying the differential across male and female observers. In the second set we assess the mechanisms by which the double standards operate, separating and quantifying two mechanisms-double standards in the just base wage (i.e., the base wage regarded as just by the observer) and in the just rate of return to schooling (i.e., the rate of return to schooling regarded as just by the observer)-establishing their direction and testing whether the mechanisms differ by observer's gender.

A search for quantitative trait loci affecting asymmetry of mandibular characters in mice.

Abstract: An interval mapping procedure was used to search for and describe the effects of any quantitative trait loci (QTLs) for directional asymmetry (DA) and fluctuating asymmetry (FA) of 10 bilateral mandible characters in house mice. It was hypothesized that more QTLs would be found for DA than for FA, but that any discovered for FA should tend to exhibit dominance. All mandible characters were triply measured and 76 microsatellite markers were scored in an average of 471 mice from the F2 intercross of the Large (LG/J) and Small (SM/J) inbred strains. A total of 16 QTLs significantly affected DA in nine of the 10 mandible characters, and this was more than the 9.5 expected by chance alone. These QTLs were found on seven of the 19 chromosomes, often at or near locations of QTLs affecting the mean of the two sides for various dimensions on the mandible. It was concluded that there is genetical variability for DA in these characters, although its level was low (4.4% of the total variation in this particular F2 population). Eleven QTLs were detected for FA, suggesting that there is very little genetic variability for FA, at least as seen in the mandible characters in this particular F2 population. As hypothesized, however, these QTLs did tend to exhibit dominance.

Global convexity in a three-dimensional inverse acoustic problem

Abstract: We consider an inverse scattering problem (ISP) for the acoustic equation $% u_{tt}=c_{}^2(x)\Delta u,u|_{t=0}=0,u_t|_{t=0}=\delta (x),x\in {\Bbb R}^3.$ The ISP consists of the determination of the speed of sound $c(x)$ inside a bounded domain $\Omega \subset {\Bbb R}^3$ given $c(x)$ outside $\Omega $ and measurements of the amplitude $u(x,t)$ of the sound at the boundary $% \partial \Omega ,\;u|_{_{\partial \Omega }}=\varphi (x,t).$ This problem is nonoverdetermined since only a single source location at $\left\{ 0\right\}$ is counted. Assuming regularity of the rays generated by $c(x)$ and using the Carleman's weight functions, we construct a cost functional $J_\lambda $. The main result is Theorem 3.1, which claims global strict convexity of $J_\lambda $ on "reasonable" compact sets of solutions. Therefore, global convergence on such a set of a number of standard minimization algorithms to the unique global minimum of $J_\lambda $ (i.e., solution of the ISP) is guaranteed. This in turn shows a possibil...

Localization of Classical Waves II: Electromagnetic Waves

Abstract: We consider electromagnetic waves in a medium described by a position dependent dielectric constant \(\). We assume that \(\) is a random perturbation of a periodic function \(\) and that the periodic Maxwell operator \(\) has a gap in the spectrum, where \(\). We prove the existence of localized waves, i.e., finite energy solutions of Maxwell's equations with the property that almost all of the wave's energy remains in a fixed bounded region of space at all times. Localization of electromagnetic waves is a consequence of Anderson localization for the self-adjoint operators \(\). We prove that, in the random medium described by \(\), the random operator \(\) exhibits Anderson localization inside the gap in the spectrum of \(\). This is shown even in situations when the gap is totally filled by the spectrum of the random operator; we can prescribe random environments that ensure localization in almost the whole gap.

Children's Understanding of the Intent of Advertising: A Meta-Analysis:

Abstract: The author conducts a meta-analysis investigating the extent to which children understand the intent of advertising. The results show several study characteristics that have contributed to variance...

Is developmental stability heritable

Abstract: The past few years have been witness to a resurgence of interest in the phenomenon of developmental stability, most often assessed by non-directional differences between right and left sides of bilateral characters known as fluctuating asymmetry, FA (Van Valen, 1962; Palmer, 1994). Several factors have contributed to this interest, including the increasingly recognized usefulness of FA in the comparison of developmental stability levels in populations believed to be stressed or not stressed by factors such as pollution, inbreeding, selection, and parasites (Zakharov, 1989; Parsons, 1990; Graham, 1992; Moller and Pomiankowski, 1993). Most recently it has been shown that high FA is correlated with reduced male mating success in three different species (Markow, 1987; Markow and Ricker, 1992; Moller, 1992; Thornhill, 1992). Although there are several potential explanations for this, one possibility is a “good genes” model of sexual selection in which females choose males with the least FA since these males may reflect a heritable quality that affects offspring viability (Maller, 1990, 1992; Moller and Pomiankowski, 1993; Thornhill, 1992). In one species of Drosophilu it has been shown that FA increases with parasitic infections, so perhaps females cue on reduced FA in males as an indicator of greater resistance to parasites, a trait that may be passed on to their offspring (Polak, 1992). Alternatively, FA may simply be an environmental consequence of parasitism and not be directly involved in the sexual selection process. But is developmental stability heritable, as it must be to play a role in at least some of these models of sexual selection? Most, but not all, of the studies using FA to estimate the heritability of developmental stability from conventional parent-offspring or sib analyses and from the results of selection, have yielded non-significant results (e.g., Leary et al., 198.5; Leamy, 1986). However, it is well known that

Remodeling of hepatic microvascular responsiveness after ischemia/reperfusion.

Abstract: Although there is substantial evidence suggesting that the integrity of the microcirculation is an important determinant of tissue viability during reperfusion after ischemia in the liver, as well as other tissues, the mechanisms responsible for microvascular failure are not fully understood. It is now recognized that the microvascular response to reperfusion, similar to the whole organism response to shock, can consist of either a rapid exacerbation of injury after a severe ischemic episode or, alternatively, a more slowly developing alteration in responsiveness that occurs after a less severe insult. In the more slowly developing response, the alterations in vascular status are the result of up-regulation of stress-induced vascular mediators such as endothelin, nitric oxide synthase (NOS), and heme oxygenase, as well as changes in the reactivity of the effector cells to the mediators. The mechanisms for change in reactivity of vascular cells range from changes in receptor expression to overt phenotypic transformation, as can occur in the hepatic stellate cells in response to repeated injury. When maintained in balance, these counteracting constrictor and dilator influences can be protective; however, local imbalance can result in focal ischemia, thus propagating the injury. Thus, the remodeling of the hepatic microvascular responsiveness during reperfusion after ischemia may serve as a useful paradigm for consideration of the overall response of the organism to shock.

State Expenditures and Policy Outcomes in Environmental Program Management

Abstract: Comparative state environmental research seeks to explain the factors contributing to intergovernmental environmental management. In pursuing the answer to this query, researchers have relied on either fiscal (expenditures) or nonfiscal (ranking) measures of state environmental effort. Respecting the debate surrounding state policy outputs and fiscal versus nonfiscal measures, we evaluate comprehensive state environmental management comparing spending and ranking measures in our analysis. Though pronounced differences do exist between the two models, we find pollution and state size to be the primary factors affecting a state's environmental effort no matter which measure is used.

Expanded norms for the controlled oral word association test

Abstract: The Controlled Oral Word Association Test (COWAT) is a measure of a person's ability to make verbal associations to specified letters (i.e., C, F, and L). This measure is a useful component of a neuropsychological battery as it is able to detect changes in word association fluency often found with various disorders. In order to generate current norms for the elderly and aid in interpreting their performance, the COWAT was administered to a group of community-dwelling elderly persons. Information regarding total numbers of words produced as well as frequency of perseverations, breaking set, using the same word stem, and using a proper noun is provided.

Development and Demonstration of Multidimensional IRT‐Based Internal Measures of Differential Functioning of ltems and Tests

Abstract: This article defines and demonstrates a framework for studying differential item functioning (DIF) and differential test functioning (DTF) for tests that are intended to be multidimensional The procedure introduced here is an extension of unidimensional differential functioning of items and tests (DFIT) recently developed by Raju, van der Linden, & Fleer (1995). To demonstrate the usefulness of these new indexes in a multidimensional IRT setting, two-dimensional data were simulated with known item parameters and known DIF and DTE The DIF and DTF indexes were recovered reasonably well under various distributional differences of Os after multidimensional linking was applied to put the two sets of item parameters on a common scale. Further studies are suggested in the area of DIF/DTF for intentionally multidimensional tests.

Detection of the viable but nonculturable state in escherichia coli o157:h7

Abstract: Enterohemorrhagic Escherichia coli 0157:H7 (EHEC) is recognized as a frequent cause of gastroenteritis ranging from mild to severe bloody diarrhea. The Shiga-like toxin produced by EHEC can result in hemolytic uremic syndrome, now the major cause of acute kidney failure in children in the United States. Inadequately cooked beef is most commonly implicated in the transmission of EHEC, although only a small fraction of cattle appear to harbor the organism. In several studies EHEC positive herds were detected only in the summer months correlating with the occurrence of human infections. Numerous E. coli strains have been shown to enter a viable but nonculturable (VBNC) state as a result of environmental stresses, including low temperature. Using traditional plating methods and the BacLight Molecular Probe, we monitored EHEC strains incubated in river water (RW) and artificial sea water (ASW) at temperatures of 5C and 25C for their entry into the VBNC state. EHEC strains remained culturable for over 40 days in both ASW and RW incubated at 25C. In ASW, these levels were higher than a non-EHEC control. At 5C, the number of culturable EHEC cells dropped gradually in both RW and ASW. Using the BacLight Molecular Probe, we were able to demonstrate that these cells, though not culturable, were viable indicating entry into the VBNC state. Our study suggests that temperature and not salinity is the primary signal for entry into this state.

Risk of addiction to work and family functioning.

Abstract: A total of 107 self-identified workaholics from across the United States and Canada responded to a set of inventories assessing their scores on the Work Addiction Risk Test and the correlations with current family functioning. Individuals in the High-risk group, compared to those in the Low- and Medium-groups, were significantly more likely to perceive their current families as having less effective problem-solving ability, worse communication, less clearly established family roles, fewer affective responses, less affective involvement, and lower general family functioning.

Evaluations of organizational effectiveness in mental health programs.

Abstract: We present a conceptual framework derived from organizational theory for understanding the evaluation of the effectiveness of mental health services. We postulate that organizations are deemed "successful" by their constituents when they conform to institutional demands and expectations that are both internally and externally generated. We empirically assess institutional conformity by examining evaluations of effectiveness by 269 mental health providers in 29 different mental health programs. Specialist programs responded to institutional demands by targeting services to those considered most in need: clients with severe mental illnesses. The formal structure and program philosophy of these programs clearly reflected this emphasis; consequently, levels of goal incongruence were low and evaluations of effectiveness were high. Generalist programs continued to provide care to diverse client groups, had more professionals, offered traditional services (such as psychotherapy), and exhibited higher levels of goal incongruence; these factors resulted in lower evaluations of effectiveness. This research is important because it demonstrates that organizational processes of institutional conformity (program objectives meet the demands of external constituents) and goal congruence (program objectives meet with expectations of internal constituents) are critical to positive evaluations of effectiveness. With the current institutional demand for effective, efficient services, it is critical that researchers have a conceptual framework for analyzing those factors which influence evaluations of effectiveness.

Restructuring of Hog Farming in North Carolina: Explosion and Implosion

Abstract: Over the past six years hog farming in North Carolina has undergone a significant restructuring. For most of this century raising hogs was a casual farm activity found throughout the state. During the past decade hog farming has been transformed along industrial-corporate lines. In the process, the swine population has expanded rapidly (exploded) and simultaneously collapsed in geographical bounds (imploded). This paper examines the linkage between the development of the industrial-corporate hog farming regime, the rapid growth in hog populations, and the geographical concentration of hog production in a newly emerging high-density hog production district in the south central area of the Coastal Plain region.

Evolutionary Algorithms — An Overview

Abstract: Evolutionary algorithms (EAs), which are based on a powerful principle of evolution: survival of the fittest, and which model some natural phenomena: genetic inheritance and Darwinian strife for survival, constitute an interesting category of modern heuristic search This introductory article presents the main paradigms of evolutionary algorithms (genetic algorithms, evolution strategies, evolutionary programming, genetic programming) and discusses other (hybrid) methods of evolutionary computation Also, various constraint-handling techniques in connection with evolutionary algorithms are discussed, since most engineering problems includes some problem-specific constraints

Women's perception. Breast cancer treatment and sexuality.

Abstract: PURPOSE The authors describe women's perceptions of how their sexuality was affected by treatment for breast cancer. This description is part of a larger study that tested the psychometric properties of a sexuality measure. DESCRIPTION OF STUDY This exploratory study analyzed 105 women's responses to one question that asked them to describe how their sexuality had changed since their breast cancer diagnosis. Two researchers independently used content analytic procedures to identify themes that emerged from the data. RESULTS Four themes emerged: Physical Sexual Functioning, Relationship Quality, Psychological Self, and Self as Female. Women who had reconstructive surgery indicated that the loss of feeling in the reconstructed breast was sexually troublesome and disappointing. Comparison of the qualitative data with quantitative data (triangulation) provided support for the finding of no significant differences in sexual functioning before women treated by lumpectomy versus mastectomy. CLINICAL IMPLICATIONS Breast cancer affects many aspects of a woman's sexuality, including changes in physical functioning and in perception of femaleness. Informed healthcare decisions cannot be made until patients are knowledgeable about the sexual outcomes of cancer therapies. Healthcare professionals must acknowledge the scope of the impact of cancer treatment on sexuality, include such information as part of the informed consent process, and provide appropriate education and referral.

Diet selection and foraging distances of African and European-African hybrid honey bee colonies in Costa Rica

Abstract: Summary Diet selection and foraging distances were compared among 3 pairs of matched colonies of African an European-African hybrid honey bees in Northwestern Costa Rica Mitochondrial DNA (mtDNA) analysis was used to classify each colony as neotropical African (possessing African mtDNA) or hybrid (possessing European mtDNA, and therefore containing workers arising from a European queen mated to African drones) African and hybrid colonies did not differ significantly in population size, the areas of comb devoted to brood rearing and food storage, flight activity, pollen foraging activity, or the distances traveled to pollen and nectar sources These nonsignificant differences suggest that the foraging behavior of the two colony types may have been more influenced by environmental factors than by genetically determined dietary or movement preferences Conversely, such genetically determined preferences may have been expressed, but African-like preferences may have been dominant within both colony types However, while no significant differences were observed, colonies with African mtDNA maintained slightly greater levels of brood rearing, had 15 times the level of pollen foraging activity, and traveled on the average 600 m less per round trip of foraging The potential influence of these slight but consistent differences on the long-term, relative success of African versus hybrid colonies is discussed