SHAREOK Repository
Not a member yet
49261 research outputs found
Sort by
Augmenting Hierarchical Visualizations with Topology-Centric Representations and Interactions
No full textAs Tufte emphasizes, “above all else, show the data”. Consistently highlighting key aspects of the data in visualizations ensures a more reliable, quick, and insightful understanding of data, particularly when interpreting various aspects of the data. This is particularly applicable for hierarchical data, which have many facets of relational information. A hierarchy is a system that organizes entities by rank, order, or importance, using parent-child relationships at its foundation. These relationships often result in derivation of various other kinds of relationships within the hierarchy, some of which are widely applicable and considered of primary importance across domains, while others are domain-specific and of special importance. Examples of these relationships include siblings, levels and paths. The nodes and edges that comprise these relationships are often collectively referred to as topologies by the visualization community. In our research, we further distinguish the topologies of single node and edge elements, referred to as basic topologies and those formed by sets of nodes and edges, which we term composite topologies. Having the ability to explicitly represent composite topologies and provide support for interactive operations on them is useful for revealing patterns, facilitating analysis, and drawing meaningful conclusions from hierarchical data. Tree visualizations are a subclass of hierarchical visualizations designed to represent data with strict parent-child relationships in a tree structure. These techniques emphasize visual clarity in conveying hierarchical depth and structural relationships. Existing tree visualization techniques and systems primarily focus on representing node entities and parent-child relationships between node entities, and to some extent supporting operations on nodes and edges. These visualizations often reveal various other composite topologies incidentally through their design. Some relationships, like parent-child relationships, are easier to interpret in these visualizations than composite topologies because they are explicitly represented. Other relationships represented by composite topologies require deliberate effort by users to interpret their structure from what they see. Explicit representation of composite topologies can allow users to see those topologies directly rather than discerning them from their constituent node and edge representations, opening new avenues for interactive data exploration and analysis of hierarchies. This research explores how existing tree visualizations represent information and how these visualizations can be extended to support representation of composite topologies and interactive operations on them. We examine the concept of topologies: the structures in a hierarchy, comprising nodes and edges, that constitute various relations. We develop a software architecture and a data pipeline to support tree visualization design, along with an implemented tree visualization system called Hieros. We conduct a user evaluation to study the usability and utility of representing various relations and interacting with them in tree visualizations. This dissertation makes five main research contributions. The first contribution is C4D3, a JavaScript-based coordination library for building coordinated multiple view visualizations using the D3 library for web-based visualizations. It is based on the Live Properties architecture of the Improvise visualization system. C4D3 aims to adapt and implement the coordination architecture of Improvise as an independent library that can be used with web-based visualization libraries such as D3, and eventually make it possible to build and coordinate tree visualizations via their topologies. The second contribution is a conceptual model of representative suitability, which is used to assess the capability and suitability of tree visualizations to represent the structures and their attributes in hierarchical data. The model aims to help in predicting how likely tree visualizations are to effectively visually represent specific topologies and the information associated with them. The third contribution is the design of Hieros, a tree visualization library with a modular software architecture and a hierarchical data pipeline. The architecture supports explicit representation of topologies and interactive operations on them at various stages of the visualization pipeline. The fourth contribution is a reference implementation of Hieros, a tree visualization library implemented in the Improvise visualization environment to support construction of topology-augmented tree visualizations. The fifth contribution is a user evaluation to assess the utility and usability of tree visualizations in explicitly representing topologies. Overall, this dissertation contributes to the systematic understanding of tree visualizations in terms of topological structures that form the building blocks of hierarchies, the building of a visualization system and data processing pipeline to support topology-centric tree visualizations, and demonstration of their application to a variety of knowledge domains
The Tired Helpers: How Media Synchronicity and Technology-Mediated Interpersonal Helping Impact Technostress in Remote Knowledge Work
No full textThe rise of remote work has highlighted the critical role of Information Communication Technologies (ICTs) in shaping organizational behaviors. While ICTs help facilitate efficient communication and collaboration, they have also given rise to a pervasive issue, technostress — stress experienced by end-users in organizations as a result of their ICT use.. Technostress impacts employee well-being and productivity and is particularly important to understand in the growing context of remote work. This dissertation examines how Technology-Mediated Interpersonal Helping (TMIH), a form of extra-role Organizational Citizenship Behaviors (OCB) facilitated by ICTs, impacts employee well-being and productivity within remote knowledge work. Drawing on Media Synchronicity Theory, which explains how communication media supports coordinated communication, and Social Presence Theory, which describes the extent to which a communication medium conveys the realness of the interacting other, this dissertation offers a new perspective on technostress by exploring the cognitive and emotional mechanisms through which TMIH affects remote workers’ well-being and productivity. Two studies were conducted: the first study found that using synchronous ICTs to help coworkers while working remotely reduces interruption overload and psychological transition. Surprisingly, intensity and extended TMIH positively influences productivity. Lastly, interruption overload, psychological transition, and task closure served as key cognitive mediators linking TMIH with technostress outcomes. The second study examined social presence as an emotional mediator and was found to alleviate technostress and improve employee wellbeing. However, social presence also increased fatigue. This dissertation contributes to research by integrating Media Synchronicity Theory and Social Presence Theory to explain how TMIH shape technostress experiences in remote work. A key contribution of this dissertation is that media synchronicity helps alleviate technology-induced strain, offering a pathway for organizations to manage technostress through strategic ICT choices
An Excellence-Based View of Virtuous Motivation
No full textIn my dissertation I explore the nature of virtuous motivation. The output of this exploration is a novel account of virtuous motivation which I argue is preferable to approaches currently available within contemporary virtue ethics. More specifically, I aim to account for the kinds of reasons that motivate virtuous individuals when they act virtuously, which involves identifying the explicit reasons that motivate them when they act as well as implicit or deeper motives that are likewise operative, although in a different way. Throughout my work, I argue that there is a central concept or specific kind of motivating reason that consistently motivates virtuous persons when they act virtuously. This is the motive to exhibit excellence or virtue in some way whenever they act. I also refer to this as the concept of “agential excellence.” Because of this I call my view the excellence-based view of virtuous motivation, since the motive for excellence is both present and sufficiently motivating in every case of virtuous motivation. Although the excellence-based view is proposed as a novel approach to the topic of virtuous motivation, it borrows its conceptual framework from Aristotle’s account of virtue. However, I depart from this framework in a significant way. Aristotle thought that because eudaimonia (or a flourishing life) was our ultimate end, all of our choices and actions were ultimately for the sake of this end. For our motives, this meant that whatever choices we made and the reasons motivating our actions, these were motivated by our ultimate desire to flourish: including the motive to be virtuous. Several contemporary virtue-ethicists reflect Aristotle’s belief that eudaimonia plays a necessary role in the motivational structure of virtuous persons (I refer to these as eudaimonist accounts of virtuous motivation). One way they argue this is through the role eudaimonia must play in our practical rationality, specifically in terms of being the ultimate terminus within our reasoning. If eudaimonia is our ultimate end, then our choices and motivating reasons for whatever we do are rational insofar as they are connected to or grounded in this desire to flourish. And if our motives are to be virtuous, they must be rational in this sense. Ultimately, when constructing an account of virtuous motivation, the default position for contemporary virtue-ethicists that follow in Aristotle’s footsteps is to claim that eudaimonia is both central to and necessary for displaying virtuous motivation. In chapter 1, I both challenge the eudaimonist view of virtuous motivation and motivate my excellence-based view. To do this, I use an example inspired by a collection of letters written by several men and women who opposed the Nazi regime and were subsequently imprisoned and executed for their resistance. I refer to this example as the Letter-Writers case. The example is intended to demonstrate how the flourishing life may not have been possible for these individuals, who I take to be virtuous, but they were still motivated to maintain their character and act nobly, despite the horrific nature of their circumstances. I argue that it is plausible that thoughts of flourishing were not decisive in motivating the Letter-Writers to act and live in a virtuous way within this situation. In other words, they exhibited virtuous motivation without being motivated by eudaimonia. This paves the way for an excellence-based view, which places “agential excellence” rather than eudaimonia, as the central concept for understanding virtuous motivation. The concept of agential excellence is inspired by Aristotle’s view of virtue, according to which virtue is understood as the excellent functioning of human beings which makes them good human beings. Basically, humans can display excellence through cultivating and maintaining virtuous character traits, acting virtuously in consistent way, and through living excellent or virtuous lives. With this concept in hand, I go on to argue that the motivating reasons of the Letter-Writers can more plausibly be connected to and grounded in the concept of agential excellence, or excellence-based reasons, rather than eudaimonia and eudaimonist reasons. Chapter 2 extends the challenge against eudaimonist virtue ethics, specifically regarding their account of virtuous motivation towards others. Recall that the eudaimonist claims that all moral motivation ultimately traces back to a desire to flourish, which naturally extends to our motives to respect and act on behalf of others. However, much like in chapter 1, there are cases of individuals acting virtuously towards others who are not also motivated by their pursuit of their own eudaimonia. In other words, virtuous persons can act and be motivated in a virtuous way towards others without also considering their own flourishing. In light of this, I argue that the eudaimonist cannot account for such cases, insofar as they insist on a strong link between virtuous motivation and flourishing. I propose that the excellence-based view can better handle cases of virtuous motivation towards others. In such cases, virtuous actions towards others are motivated by a deep care and concern for them, combined with a desire to express that care excellently. Where deep other-concern and a desire to express that concern in a virtuous way are present, virtuous motivation emerges. For chapter 3, we take a bit of a detour. In chapters 1 and 2, virtuous motivation was largely influenced by the exercise of one’s practical rationality. And since there is a form of practical rationality or deliberation that is characteristic of virtuous persons and since both Aristotle and several contemporary virtue-ethicists claim that eudaimonia must guide this deliberation, the argument in chapter 3 challenges this view. I do this by considering cases where virtuous persons deliberate excellently about how to act and live but do not employ a conception of a flourishing life when doing so. Perhaps such individuals deliberate in accordance with what is virtuous to do, what expresses a virtuous character, or what is consistent with a virtuous life. These considerations led me to propose an “excellence-based view of practical wisdom”, which claims that practical wisdom can always be guided by the concept of agential excellence, whether this is situated within a broader desire to flourish. And when guided by agential excellence, one can deliberate effectively to determine what’s best to do for any circumstance. Thus, the excellence-based view provides a plausible alternative to eudaimonist accounts of practical wisdom. I also argue that an excellence-based view is preferable to the eudaimonist view, since agential excellence can provide consistent deliberative guidance across different lives and when agential excellence guides practically wise deliberation, this still positions us well to attain a flourishing life. In chapter 4, I return to the main discussion of virtuous motivation and consider alternative virtue-ethical approaches to the topic. The alternatives I have mind are Stoicism (in both ancient and contemporary form), Michael Slote’s care-based ethics, and Christine Swanton’s target-centered virtue ethics. The goal of this chapter was to illustrate how an excellence-based view of virtuous motivation fares better than these alternative views. To do this, I examine each alternative view to show what their account of virtuous motivation would look like alongside its merits and deficiencies. The upshot of considering these alternative views is that an excellence-based view can incorporate the attractive elements of each view, it can avoid the problems of such views, and, most importantly, can capture what can be found in every instance of virtuous motivation
Negative expressions as parts of logos in Plato’s Sophist
No full textIn the thesis, I offer an interpretation of the middle part of the Sophist, according to which its goal is to construct an account of meaningful language (logos) that welcomes negativity. I argue that non being is a part of logos in two senses: as negative predicates (257b-c) and as false statements (259e-263d). Following the incompatible property range view proposed by Lesley Brown, I argue that Plato’s account of negative predication is about internal negation, as opposed to external negation defended by scholars such as G.E.L. Owen. Further, I argue that according to Plato, meaningful language is a proper mixture of heterofunctional parts of speech: subjects and predicates. The improper mixture of a subject with a predicate results in a false statement. However, a false statement is still a part of logos, because it takes the wrong predicate from the right predicate-range
PREDICTION OF LENGTH OF STAY AMONG PREECLAMPTIC PATIENTS USING SUPERVISED LEARNING METHODS
Full text linkHypertensive disorders during pregnancy, particularly preeclampsia, are among the leading causes of maternal and neonatal mortality. In the United States, preeclampsia affects approximately 2 to 8% of pregnancies, with a higher incidence among African American women (6.04%) compared to Caucasian women (3.75%). Due to its severity, preeclampsia often requires intensive care unit (ICU) intervention, resulting in prolonged hospital stays. This study aims to predict the length of stay (LOS) for preeclamptic patients using supervised machine learning on a highly imbalanced dataset. We adopted two modeling approaches: classification and regression, and evaluated multiple algorithms, including logistic regression, decision tree, SVM, KNN, random forest, XGBoost, linear regression, and elastic net. To address class imbalance, we employed oversampling techniques (SMOTE, ADASYN, SMOGN) and cost sensitive learning strategies. Our findings show that cost sensitive logistic regression achieved the highest classification performance with AUC of 66% and G-mean of 60%. Additionally, the analysis revealed that African American women tend to have longer hospital stays. This research supports improved hospital resource allocation, staff planning, and early intervention for high risk cases, contributing to more efficient and equitable healthcare delivery
STREAMSCOPE: FIXED-MOUNT LASER SCANNING INSTRUMENTATION FOR REMOTE STREAM GAUGING IN SHALLOW RIVERS WITH FREQUENTLY CHANGING GEOMORPHOLOGIES
Full text linkAccurate streamflow monitoring in shallow rivers with frequently changing geomorphology poses a unique challenge, particularly in remote and ungauged locations. This thesis presents a novel approach developed in collaboration with the United States Geological Survey (USGS) to generate real-time discharge estimates using a low-power, non-contact sensor system. StreamScope integrates a Class II 620 nm laser rangefinder with an ultrasonic sensor to remotely measure river cross-sectional geometry and develop stage–area ratings. Through onboard automation, the system captures highresolution bathymetric data, enabling continuous discharge estimation without physical contact with the stream. Laboratory experiments were conducted to evaluate the selected laser rangefinder under varying conditions of solar radiation, water turbidity, water depth, bottom substrate, and sensor height. The results demonstrated that the unit operates best under low solar radiation, is capable of obtaining measurements under low turbidity up to 20 NTU, and that the laser’s returns may serve as a proxy for turbidity. Additionally, the tests established the operational limits of the sensor. The field deployment at Falls Creek in Davis, Oklahoma, demonstrated the robustness and precision of the instrument in a dynamic, real-world environment. The data collected provided a significant improvement in resolution compared to a traditional USGS stream survey
Variability, Multi-wavelength Properties, and Environments of Active Galactic Nuclei
Full text linkIn the early twentieth century, Albert Einstein predicted the existence of black holes with his theory of general relativity. Over the past century, astronomers discovered many evidences that prove Einstein right. One of the most extreme cases of black holes is the supermassive black holes (SMBHs) found at the centers of most galaxies, with masses ranging from millions to billions of solar masses. Some of them are known to be actively consuming surrounding gas and dust, emitting a tremendous amount of energy during this process. These are called active galactic nuclei (AGNs), and these are some of the most energetic phenomena in the universe. AGNs are fascinating objects to study, as they are related to a number of areas in astronomy such as galaxy evolution and black hole physics. One of prominent features of AGNs is variability; their brightness is always changing over time. Observations show that the AGN variability is stochastic, or a "red noise", which means that the brightness difference increases as a function of time lag. This relation follows an approximate power law relation. However, past a certain time lag threshold, the power law index shifts to a smaller value. This point is called the break frequency, and this parameter is known to be correlated with the SMBH mass, suggesting that variability is closely related to the fundamental nature of AGNs. To better understand the nature of AGNs, the AGN variability was analyzed in a few different ways in this dissertation. First, variability characteristics of a sample of galaxies, computed using the data from All-Sky Automated Survey for SuperNovae (ASAS-SN), were examined to distinguish AGNs from quiescent galaxies. By constraining the AGN fraction among galaxies, the timescale of AGN activities compared to galaxies’ age can be estimated. Then the multi-wavelength and environmental properties of the variability selected AGNs are analyzed. Second, the AGN break frequencies in optical power spectral densities (PSDs) are measured and compared to X-ray breaks. Current AGN models suggest that different regions around the AGN emit light at different wavelengths—shorter wavelength from near the central SMBH and longer wavelength from outer parts. If there is a correlation between optical and X-ray break frequencies, it can provide clues on the structure of AGNs and interactions between different regions. To achieve this goal, the optical break frequencies were measured using the data from ASAS-SN and Transiting Exoplanet Survey Satellite (TESS) on the sample of AGNs with X-ray break frequencies previously measured. With these methods, this study can contribute to the understanding of AGNs in both temporal and spatial terms. The variability selection method showed that approximately 3% of galaxies are AGNs, and about 80% of them are classified as low-luminosity AGNs (LLAGNs). Because a portion of luminous AGNs are excluded from the parent galaxy sample, the true AGN fraction may be greater. LLAGNs are a subcategory of AGNs that display signs of activity, but not very energetic. This dissertation shows that LLAGNs most likely reside in denser environments compared to luminous AGNs, suggesting they may be triggered by different mechanisms compared to luminous AGNs. This result provides clues on timescales of different stages and evolution of AGN activities. Upon multi-wavelength analysis, the variability selected AGNs are often not classified as AGNs by traditional methods, meaning that this method provides a useful tool for discovering a larger population of AGNs, especially in the era of big data, as this procedure is automated and versatile so it can be used to any sets of data. From the optical PSDs, a set of break frequencies is measured that is consistent with previous studies. In addition, a new set of break frequencies that is 1--2 orders of magnitude greater is also discovered. The high-frequency optical breaks displayed approximately 1-to-1 correlation with X-ray break frequencies, but with an offset in order of a few days. This can be interpreted as the X-ray variability driving the optical variability with a time delay, as it takes time for light to travel from one region to another. The size estimate from this time delay is consistent with measurements from previous studies, suggesting that this method introduces a new way to analyze the AGN structure
Film Blowing of Biobased Biodegradable Polyesters: Poly(Pentylene Adipate-co-Terephthalate) and Poly (DodecyleneFuranoate)
Full text linkFinancial support was provided by the University of Oklahoma Libraries' Open Access Fund.Poly(pentylene adipate-co-terephthalate) (PPeAT), poly (dodecylene furanoate) (PDDF), polybutylene adipate terephthalate(PBAT), and linear low-density polyethylene (LLDPE) films were prepared using film blowing. Machine direction (MD) andtransverse direction (TD) properties of the blown films (BFs) are compared to the properties of compression molded sheets (CMSs).For all polymers, Young’s modulus, stress at break elongation at break and storage modulus are higher for the CMSs vs. BFs. PPeATfilms have a higher modulus than PBAT films demonstrating its superior mechanical properties. X-ray scattering shows that CMSshave higher percent crystallinity, longer d-spacing, and larger crystal size compared with BFs. For BFs, SAXS measurements havemore intensity in the MD vs. the TD while the d-spacing is slightly higher for the MD; however, WAXS results indicate that films inthe TD have higher percent crystallinity than in the MD. CMSs exhibit lower oxygen permeability, carbon dioxide permeability, andnormalized water vapor transmission rates compared with BFs consistent with the higher crystallinity. Biobased, biodegradablePPeAT and PDDF show lower oxygen and carbon dioxide permeabilities compared with fossil fuel-based PBAT and LLDPE andlower water vapor transmission rates than PBAT. PPeAT and PDDF BFs show promising results and eventually might be used asa drop-in replacement for LLDPE in flexible film packaging.Ye
A Pedagogical Guide to and Analysis of Sixty Trombone Quartets
Full text linkThe staple of trombone chamber music is the trombone quartet; some authors have even described it as the trombone ensemble. However, no resources are solely dedicated to the ensemble’s repertoire, whether it be demographic information, piece descriptions, a standardized grading system, or a combination of these items. Many standard pedagogical texts merely list recommended quartets by title, composer, and publisher without providing any other details; authors also rarely assign a difficulty level to any of the works within their lists. Since instructors often claim the importance and value of chamber music, the works they select serve as both the textbook and curriculum in applied studio instruction. Given the limited information published on trombone quartet music, there remains a clear gap within low brass instructional resources available to teachers. The purpose of this study was to analyze and assign a difficulty (grade) level to sixty trombone quartets selected from a variety of sources written by trombone pedagogues (Denis Wick, Edward Kleinhammer, Buddy Baker, Marta Jean Hofacre, and Robin Gregory, etc.) and compile them into an annotated database. Each entry consists of three parts: (1) the work’s demographic information (composer, arranger, title, movements, duration, publisher, availability, range, clefs, mutes, etc.); (2) a piece description (i.e., a written commentary and analysis); and (3) an assigned difficulty level. As instructors continue looking for new repertoire, this pedagogical resource will assist instructors with making informed decisions, so that their selections can align with their curriculum and simultaneously challenge students while remaining accessible. The document also is accessible to students, so that they can be active in their own repertoire selection (via an online database)
MULTIMODAL BEARING FAULT CLASSIFICATION UNDER VARIABLE CONDITIONS: A PHYSICS-INFORMED 1D CNN WITH TRANSFER LEARNING
No full textBearings play an integral role in ensuring the reliability and efficiency of rotating machinery by reducing friction and handling critical loads. Bearing failures, which account for the majority of mechanical faults, highlight the imperative need for reliable condition monitoring and fault classification. This study proposes a multimodal bearing fault classification approach that leverages vibration and two motor phase current signals within a one-dimensional convolutional neural network (1D CNN) framework. The proposed method fuses feature from multiple signals to improve the accuracy of fault classification and systematically investigates the impact of regularization strategies—including L1, L2, and Dropout—on model performance and overfitting. The methodology is extensively evaluated on the Paderborn University (PU) Bearing Dataset under multiple operating conditions, allowing for a comprehensive analysis of the framework’s adaptability and effectiveness. Additionally, the framework is enriched by integrating a physics-informed branch utilizing vibration signal envelope spectra to extract characteristic fault frequencies, in particular, the ball pass frequency of the outer race (BPFO) and inner race (BPFI). Furthermore, a physics-informed loss function is incorporated to enforce physically consistent predictions, enabling the model to leverage domain knowledge for enhanced learning and interpretation. For adaptability across varying operational environments, three transfer learning strategies are introduced. The integration of domain knowledge through physics-informed features, in combination with transfer learning strategies, enables the framework to more accurately capture underlying faults and adapt to a range of operational conditions. Overall, this multimodal 1D CNN framework augmented with late fusion, advanced regularization, physics-informed element, and transfer learning strategies, lays a strong foundation for accurate, adaptable, and interpretable bearing fault classification. The proposed approach is robust to changes in operating conditions and offers practical benefits for industrial environments for reliable fault diagnosis and condition monitoring of critical machineries