Showing papers by "University of North Texas published in 2009"

Map-matching for low-sampling-rate GPS trajectories

Abstract: Map-matching is the process of aligning a sequence of observed user positions with the road network on a digital map. It is a fundamental pre-processing step for many applications, such as moving object management, traffic flow analysis, and driving directions. In practice there exists huge amount of low-sampling-rate (e.g., one point every 2--5 minutes) GPS trajectories. Unfortunately, most current map-matching approaches only deal with high-sampling-rate (typically one point every 10--30s) GPS data, and become less effective for low-sampling-rate points as the uncertainty in data increases. In this paper, we propose a novel global map-matching algorithm called ST-Matching for low-sampling-rate GPS trajectories. ST-Matching considers (1) the spatial geometric and topological structures of the road network and (2) the temporal/speed constraints of the trajectories. Based on spatio-temporal analysis, a candidate graph is constructed from which the best matching path sequence is identified. We compare ST-Matching with the incremental algorithm and Average-Frechet-Distance (AFD) based global map-matching algorithm. The experiments are performed both on synthetic and real dataset. The results show that our ST-matching algorithm significantly outperform incremental algorithm in terms of matching accuracy for low-sampling trajectories. Meanwhile, when compared with AFD-based global algorithm, ST-Matching also improves accuracy as well as running time.

It Takes Two: A Dyadic Analysis of Civil War Duration and Outcome

Abstract: Theories of conflict emphasize dyadic interaction, yet existing empirical studies of civil war focus largely on state attributes and pay little attention to nonstate antagonists. We recast civil war in a dyadic perspective, and consider how nonstate actor attributes and their relationship to the state influence conflict dynamics. We argue that strong rebels, who pose a military challenge to the government, are likely to lead to short wars and concessions. Conflicts where rebels seem weak can become prolonged if rebels can operate in the periphery so as to defy a government victory yet are not strong enough to extract concessions. Conflicts should be shorter when potential insurgents can rely on alternative political means to violence. We examine these hypotheses in a dyadic analysis of civil war duration and outcomes, using new data on nonstate actors and conflict attributes, finding support for many of our conjectures.

Soft colloids make strong glasses.

Abstract: Glass formation in colloidal suspensions has many of the hallmarks of glass formation in molecular materials. For hard-sphere colloids, which interact only as a result of excluded volume, phase behaviour is controlled by volume fraction, phi; an increase in phi drives the system towards its glassy state, analogously to a decrease in temperature, T, in molecular systems. When phi increases above phi* approximately 0.53, the viscosity starts to increase significantly, and the system eventually moves out of equilibrium at the glass transition, phi(g) approximately 0.58, where particle crowding greatly restricts structural relaxation. The large particle size makes it possible to study both structure and dynamics with light scattering and imaging; colloidal suspensions have therefore provided considerable insight into the glass transition. However, hard-sphere colloidal suspensions do not exhibit the same diversity of behaviour as molecular glasses. This is highlighted by the wide variation in behaviour observed for the viscosity or structural relaxation time, tau(alpha), when the glassy state is approached in supercooled molecular liquids. This variation is characterized by the unifying concept of fragility, which has spurred the search for a 'universal' description of dynamic arrest in glass-forming liquids. For 'fragile' liquids, tau(alpha) is highly sensitive to changes in T, whereas non-fragile, or 'strong', liquids show a much lower T sensitivity. In contrast, hard-sphere colloidal suspensions are restricted to fragile behaviour, as determined by their phi dependence, ultimately limiting their utility in the study of the glass transition. Here we show that deformable colloidal particles, when studied through their concentration dependence at fixed temperature, do exhibit the same variation in fragility as that observed in the T dependence of molecular liquids at fixed volume. Their fragility is dictated by elastic properties on the scale of individual colloidal particles. Furthermore, we find an equivalent effect in molecular systems, where elasticity directly reflects fragility. Colloidal suspensions may thus provide new insight into glass formation in molecular systems.

The Lie Detector: Explorations in the Automatic Recognition of Deceptive Language

Abstract: In this paper, we present initial experiments in the recognition of deceptive language. We introduce three data sets of true and lying texts collected for this purpose, and we show that automatic classification is a viable technique to distinguish between truth and falsehood as expressed in language. We also introduce a method for class-based feature analysis, which sheds some light on the features that are characteristic for deceptive text.

The impact of client treatment preferences on outcome: a meta‐analysis

Abstract: An important part of evidence-based practice is to include client preferences in the treatment decision-making process. However, based on previous reviews of the literature there is some question as to whether including client preferences actually has an effect on treatment outcome. This meta-analytic review summarized data from over 2,300 clients across 26 studies comparing the treatment outcome differences between clients matched to a preferred treatment and clients not matched to a preferred treatment. The findings indicate a small significant effect (r=.15, CI(.95): .09 to .21) in favor of clients who received a preferred treatment. The binomial effect size indicated that matched clients have a 58% chance of showing greater improvement, and further analysis indicate that they are about half as likely to drop-out of treatment when compared with clients not receiving a preferred treatment. Study design was seen to be a moderating variable in that partially randomized preference trials may underestimate the treatment preference effect. Implications for best practice standards are discussed.

Graph Directed Markov Systems: Geometry and Dynamics of Limit Sets

Abstract: The main focus of this book is the exploration of the geometric and dynamic properties of a far reaching generalization of a conformal iterated function system - a Graph Directed Markov System. These systems are very robust in that they apply to many settings that do not fit into the scheme of conformal iterated systems. The basic theory is laid out here and the authors have touched on many natural questions arising in its context. However, they also emphasise the many issues and current research topics which can be found in original papers. For example the detailed analysis of the structure of harmonic measures of limit sets, the examination of the doubling property of conformal measures, the extensive study of generalized polynomial like mapping or multifractal analysis of geometrically finite Kleinian groups. This book leads readers onto frontier research in the field, making it ideal for both established researchers and graduate students.

The global distribution of net primary production: resolving the paradox

Abstract: The distribution of the diversity and abundance of life on Earth is thought to be shaped by the patterns of plant growth (net primary production, NPP) in the oceans and on land. The well-known latitudinal gradient of species diversity reaches its maximum in tropical rain forests, which are considered to be the most productive ecosystems on the planet. However, this high tropical productivity on land is the opposite of the well-documented distribution of marine productivity, which is greatest in the high-latitude oceans around the poles. This paradox can be resolved by a reevaluation of the terrestrial productivity gradient. Compilations of direct measurements of forest NPP show that annual NPP in tropical forests is no different than annual NPP in temperate forests, contrary to recent syntheses and to the output of global vegetation models. Other properties of forest ecosystems, such as basal area of trees, wood density, and the ratio of wood to leaf production, as well as animal properties such as body size, population density, and reproductive rates, support the conclusion that ecologically relevant terrestrial productivity is actually highest in the temperate latitudes, reaching a maximum between 30° and 50° before declining toward the poles. This “reversal” of the latitudinal productivity gradient, if substantiated by a systematic global sampling effort, will necessitate a major reevaluation of ecological and evolutionary theory, as well as conservation strategies and international development policies.

Omalizumab for the treatment of exacerbations in children with inadequately controlled allergic (IgE-mediated) asthma

Abstract: Background Many children with asthma continue to experience symptoms despite available therapies. Objective This study evaluated the efficacy and safety of omalizumab, a humanized anti-IgE mAb, in children with moderate-to-severe persistent allergic (IgE-mediated) asthma that was inadequately controlled despite treatment with medium-dose or high-dose inhaled corticosteroids (ICSs) with or without other controller medications. Methods A randomized, double-blind, placebo-controlled trial enrolled children age 6 to Results A total of 627 patients (omalizumab, n=421; placebo, n=206) were randomized, with efficacy analyzed in 576 (omalizumab, n=384; placebo, n=192). Over the 24-week fixed-steroid phase, omalizumab reduced the rate of clinically significant asthma exacerbations (worsening symptoms requiring doubling of baseline ICS dose and/or systemic steroids) by 31% versus placebo (0.45 vs 0.64; rate ratio, 0.69; P = .007). Over a period of 52 weeks, the exacerbation rate was reduced by 43% versus placebo ( P Conclusion Add-on omalizumab is effective and well tolerated as maintenance therapy in children (6 to

Text-to-Text Semantic Similarity for Automatic Short Answer Grading

Abstract: In this paper, we explore unsupervised techniques for the task of automatic short answer grading. We compare a number of knowledge-based and corpus-based measures of text similarity, evaluate the effect of domain and size on the corpus-based measures, and also introduce a novel technique to improve the performance of the system by integrating automatic feedback from the student answers. Overall, our system significantly and consistently outperforms other unsupervised methods for short answer grading that have been proposed in the past.

The Legitimacy Puzzle in Latin America: Political Support and Democracy in Eight Nations

Abstract: Political scientists have worried about declining levels of citizens' support for their regimes (legitimacy), but have failed to empirically link this decline to the survival or breakdown of democracy. This apparent paradox is the 'legitimacy puzzle', which this book addresses by examining political legitimacy's structure, sources, and effects. With exhaustive empirical analysis of high-quality survey data from eight Latin American nations, it confirms that legitimacy exists as multiple, distinct dimensions. It finds that one's position in society, education, knowledge, information, and experiences shape legitimacy norms. Contrary to expectations, however, citizens who are unhappy with their government's performance do not drop out of politics or resort mainly to destabilizing protest. Rather, the disaffected citizens of these Latin American democracies participate at high rates in conventional politics and in such alternative arenas as communal improvement and civil society. And despite regime performance problems, citizen support for democracy remains high.

Psychopathy: assessment and forensic implications

Abstract: Psychopathy is commonly viewed as a personality disorder defined by a cluster of interpersonal, affective, lifestyle, and antisocial traits and behaviours, including grandiosity, egocentricity, deceptiveness, shallow emotions, lack of empathy or remorse, irresponsibility, impulsivity, and a tendency to violate social norms. In our article, we outline standard methods for the assessment of psychopathy, its association with antisocial personality disorder (ASPD), and its implications for clinical and forensic issues, including crime and violence, risk assessment, and treatment options.

Transformational Play as a Curricular Scaffold: Using Videogames to Support Science Education

Abstract: Drawing on game-design principles and an underlying situated theoretical perspective, we developed and researched a 3D game-based curriculum designed to teach water quality concepts. We compared undergraduate student dyads assigned randomly to four different instructional design conditions where the content had increasingly level of contextualization: (a) expository textbook condition, (b) simplistic framing condition, (c) immersive world condition, and (d) a single-user immersive world condition. Results indicated that the immersive-world dyad and immersive-world single user conditions performed significantly better than the electronic textbook group on standardized items. The immersive-world dyad condition also performed significantly better than either the expository textbook or the descriptive framing condition on a performance-based transfer task, and performed significantly better than the expository textbook condition on standardized test items. Implications for science education, and consistent with the goals of this special issue, are that immersive game-based learning environments provide a powerful new form of curriculum for teaching and learning science.

Barriers to adopting technology for teaching and learning in Oman

Abstract: This study investigates the perceived barriers to adopting information and communication technologies (ICT) in Omani higher education. One hundred faculty members from four different departments at the College of Applied Sciences in Oman participated in the study. The participants took a survey, which was developed based on the Western literature. Five factors were extracted from the survey: lack of equipment, lack of institutional support, disbelief of ICT benefits, lack of confidence, and lack of time. The findings showed that the faculty members perceived moderate degrees of barriers in applying ICT to their teaching practices. Group differences based on gender, academic rank, and academic field were generally not found except for the interaction effects on the barriers related to lack of equipment, disbelief of ICT benefits, and the overall mean. Male faculty members with less usage of ICT perceived more barriers regarding the lack of computing equipment, disbeliefs of ICT benefits, and the overall barrier than the female counterparts. It is recommended that the survey be further refined to include more subtle and culturally relevant items, larger sample sizes, and more heterogeneous samples to validate and extend the findings. Important implications of this study include a need to provide more institutional support, technical training, and personal time for faculty members to learn and upgrade their knowledge and skills in educational technologies.

Female Collegiate Athletes: Prevalence of Eating Disorders and Disordered Eating Behaviors

Abstract: Objective: The authors assessed the prevalence of pathogenic eating and weight-control behaviors among female college athletes, using a psychometrically valid measure. Participants: Participants were 204 college athletes (M age = 20.16 years, SD = 1.31 years) from 17 sports at 3 universities. On average, they participated in their sport for 10.88 years (SD = 16.68 years) and on their college team for 2.10 years (SD = 1.03 years). Methods: Participants completed a demographic and weight background questionnaire, Questionnaire for Eating Disorder Diagnoses, and the Bulimia Test-Revised. Results: The authors classified participants as eating disordered (n = 4, 2.0%), symptomatic (n = 52, 25.5%), and asymptomatic (n = 148, 72.5%). Few participants engaged in binge eating; most used exercise, as opposed to vomiting, dieting, laxatives, or diuretics, to control their weight. Conclusions: Female athletes suffer from eating disorders, and most experience symptom levels that are subclinical but problematic.

Beyond Engagement:Toward a Framework and Operational Definition for Employee Work Passion:

Abstract: The purpose of this article is to respond to the lack of consistency in the academic and practitioner literature regarding the construct of employee engagement and to offer a platform for the resea...

Anatomy of a mobilized lesson: Learning my way

Abstract: With the mass adoption of mobile computing devices by the current school generation, significant opportunities have emerged for genuinely supporting differentiated and personalized learning experiences through mobile devices. In our school-based research work in introducing mobilized curricula to a class, we observe one compelling mobilized lesson that exploits the affordances of mobile learning to provide multiple learning pathways for elementary grade (primary) 2 students. Through the lesson, students move beyond classroom activities that merely mimic what the teacher says and does in the classroom, and yet they still learn in personally meaningful ways. In deconstructing the lesson, we provide an in-depth analysis of how the affordances of mobile computing enable personalized learning from four facets: (a) allowing multiple entry points and learning pathways, (b) supporting multi-modality, (c) enabling student improvisation in situ, and (d) supporting the sharing and creation of student artifacts on the move. A key property of mobile technology that enables these affordances lies with the small form factor and the lightweightness of these devices which make them non-obtrusive in the learning spaces of the student. This article makes a contribution on the design aspects of mobilized lessons, namely, what the affordances of mobile technologies can enable.

Crystallographic Observation of Dynamic Gas Adsorption Sites and Thermal Expansion in a Breathable Fluorous Metal–Organic Framework†

Abstract: Playing accordion: Cooling a single crystal of a microporous fluorous metal-organic framework under ambient atmosphere leads to very large breathing upon gas adsorption, during which multiple N(2) molecules are filled into channels and cages (see picture). While the framework exhibits remarkable positive thermal expansion under vacuum, a gigantic apparent negative thermal expansion takes place when the crystal is exposed to N(2) at ambient pressure.

Service quality, customer satisfaction, and behavioral intentions in fast‐food restaurants

Abstract: Purpose – This study aims to explore the potential dimensions of service quality, and examine the relationship among service quality, food quality, perceived value, customer satisfaction and behavioral intentions in fast‐food restaurants (FFRs).Design/methodology/approach – The construct reliability and validity was assessed using exploratory factor analysis and confirmatory factor analysis. Structural equation modeling was employed to estimate the relationship among service quality, customer satisfaction, and behavioral intentions.Findings – Results indicated that five dimensions were significant: tangibles, reliability/responsiveness, recovery, assurance, and empathy. Service quality and food quality were two main determinants of customer satisfaction. The insignificance of perceived value is potentially due to the homogeneous nature of the construct within the FFR group rather than the importance of the perceived value construct within food service.Originality/value – The FFR success model, using the o...

Why people do what they do to protect against earthquake risk: perceptions of hazard adjustment attributes.

Abstract: This study examined respondents' self-reported adoption of 16 hazard adjustments (preimpact actions to reduce danger to persons and property), their perceptions of those adjustments' attributes, and the correlations of those perceived attributes with respondents' demographic characteristics. The sample comprised 561 randomly selected residents from three cities in Southern California prone to high seismic risk and three cities from Western Washington prone to moderate seismic risks. The results show that the hazard adjustment perceptions were defined by hazard-related attributes and resource-related attributes. More significantly, the respondents had a significant degree of consensus in their ratings of those attributes and used them to differentiate among the hazard adjustments, as indicated by statistically significant differences among the hazard adjustment profiles. Finally, there were many significant correlations between respondents' demographic characteristics and the perceived characteristics of hazard adjustments, but there were few consistent patterns among these correlations.

Ru(II) catalysts supported by hydridotris(pyrazolyl)borate for the hydroarylation of olefins: reaction scope, mechanistic studies, and guides for the development of improved catalysts.

Abstract: Carbon−carbon bond formation is the central method by which synthetic chemists add complexity, which often represents value, to molecules. Uniting a carbon chain with an aromatic substrate to yield an alkyl arene product is thus a molecular means of creating value-added materials. A traditional method for generating alkyl arenes is Friedel−Crafts catalysis, in which an alkyl halide or olefin is activated to react with an aromatic substrate. Unfortunately, despite the development of new generations of solid-state catalysts, the reaction often requires relatively harsh conditions and frequently gives poor to moderate selectivity. Conversely, a halide can first be incorporated into the aromatic ring, and the aryl halide can subsequently be joined by a variety of catalytic coupling techniques. But generating the aryl halide itself can be problematic, and such methods typically are not atom-economical. The addition of aromatic C−H bonds across the C−C double bonds of olefins (olefin hydroarylation) is therefor...

High-redshift sdss quasars with weak emission lines

Abstract: We identify a sample of 74 high-redshift quasars ( z> 3) with weak emission lines from the Fifth Data Release of the Sloan Digital Sky Survey and present infrared, optical, and radio observations of a subsample of four objects at z> 4. These weak emission-line quasars (WLQs) constitute a prominent tail of the Lyα + N v equivalent width distribution, and we compare them to quasars with more typical emission-line properties and to low-redshift active galactic nuclei with weak/absent emission lines, namely BL Lac objects. We find that WLQs exhibit hot (T ∼ 1000 K) thermal dust emission and have rest-frame 0.1–5 μm spectral energy distributions that are quite similar to those of normal quasars. The variability, polarization, and radio properties of WLQs are also different from those of BL Lacs, making continuum boosting by a relativistic jet an unlikely physical interpretation. The most probable scenario for WLQs involves broad-line region properties that are physically distinct from those of normal quasars.

Orphan LuxR regulators of quorum sensing.

Abstract: Bacteria can modulate their behavior by releasing and responding to the accumulation of signal molecules. This population co-ordination, referred to as quorum sensing, is prevalent in Gram-negative and Gram-positive bacteria. The essential constituents of quorum-sensing systems include a signal producer, or synthase, and a cognate transcriptional regulator that responds to the accumulated signal molecules. With the availability of bacterial genome sequences and an increased elucidation of quorum-sensing circuits, genes that code for additional transcriptional regulators, usually in excess of the synthase, have been identified. These additional regulators are referred to as 'orphan' regulators, because they are not directly associated with a synthase. Here, we review orphan regulators characterized in various Gram-negative bacteria and their role in expanding the bacterial regulatory network.

Palindromic richness

Abstract: In this paper, we study combinatorial and structural properties of a new class of finite and infinite words that are 'rich' in palindromes in the utmost sense. A characteristic property of the so-called rich words is that all complete returns to any palindromic factor are themselves palindromes. These words encompass the well-known episturmian words, originally introduced by the second author together with Droubay and Pirillo in 2001 [X. Droubay, J. Justin, G. Pirillo, Episturmian words and some constructions of de Luca and Rauzy, Theoret. Comput. Sci. 255 (2001) 539-553]. Other examples of rich words have appeared in many different contexts. Here we present the first unified approach to the study of this intriguing family of words. Amongst our main results, we give an explicit description of the periodic rich infinite words and show that the recurrent balanced rich infinite words coincide with the balanced episturmian words. We also consider two wider classes of infinite words, namely weakly rich words and almost rich words (both strictly contain all rich words, but neither one is contained in the other). In particular, we classify all recurrent balanced weakly rich words. As a consequence, we show that any such word on at least three letters is necessarily episturmian; hence weakly rich words obey Fraenkel's conjecture. Likewise, we prove that a certain class of almost rich words obeys Fraenkel's conjecture by showing that the recurrent balanced ones are episturmian or contain at least two distinct letters with the same frequency. Lastly, we study the action of morphisms on (almost) rich words with particular interest in morphisms that preserve (almost) richness. Such morphisms belong to the class of P-morphisms that was introduced by Hof, Knill, and Simon in 1995 [A. Hof, O. Knill, B. Simon, Singular continuous spectrum for palindromic Schrodinger operators, Comm. Math. Phys. 174 (1995) 149-159].

Quality of Research Design Moderates Effects of Grade Retention on Achievement: A Meta-Analytic, Multilevel Analysis

Abstract: The present meta-analysis examines the effect of grade retention on academic outcomes and investigates systemic sources of variability in effect sizes. Using multilevel modeling (MLM), the authors investigate characteristics of 207 effect sizes across 22 studies published between 1990 and 2007 at two levels: the study (between) and individual (within) levels. Design quality is a study-level variable. Individual-level variables are median grade retained and median number of years postretention. Quality of design is associated with less negative effects. Years postretention is negatively associated with retention effects, and this effect is stronger for studies using grade comparisons versus age comparisons. The results challenge the widely held view that retention has a negative impact on achievement. Suggestions for future research are discussed.