9,262 research outputs found

    Meso-scale FDM material layout design strategies under manufacturability constraints and fracture conditions

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    In the manufacturability-driven design (MDD) perspective, manufacturability of the product or system is the most important of the design requirements. In addition to being able to ensure that complex designs (e.g., topology optimization) are manufacturable with a given process or process family, MDD also helps mechanical designers to take advantage of unique process-material effects generated during manufacturing. One of the most recognizable examples of this comes from the scanning-type family of additive manufacturing (AM) processes; the most notable and familiar member of this family is the fused deposition modeling (FDM) or fused filament fabrication (FFF) process. This process works by selectively depositing uniform, approximately isotropic beads or elements of molten thermoplastic material (typically structural engineering plastics) in a series of pre-specified traces to build each layer of the part. There are many interesting 2-D and 3-D mechanical design problems that can be explored by designing the layout of these elements. The resulting structured, hierarchical material (which is both manufacturable and customized layer-by-layer within the limits of the process and material) can be defined as a manufacturing process-driven structured material (MPDSM). This dissertation explores several practical methods for designing these element layouts for 2-D and 3-D meso-scale mechanical problems, focusing ultimately on design-for-fracture. Three different fracture conditions are explored: (1) cases where a crack must be prevented or stopped, (2) cases where the crack must be encouraged or accelerated, and (3) cases where cracks must grow in a simple pre-determined pattern. Several new design tools, including a mapping method for the FDM manufacturability constraints, three major literature reviews, the collection, organization, and analysis of several large (qualitative and quantitative) multi-scale datasets on the fracture behavior of FDM-processed materials, some new experimental equipment, and the refinement of a fast and simple g-code generator based on commercially-available software, were developed and refined to support the design of MPDSMs under fracture conditions. The refined design method and rules were experimentally validated using a series of case studies (involving both design and physical testing of the designs) at the end of the dissertation. Finally, a simple design guide for practicing engineers who are not experts in advanced solid mechanics nor process-tailored materials was developed from the results of this project.U of I OnlyAuthor's request

    Identity, Power, and Prestige in Switzerland's Multilingual Education

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    Switzerland is known for its multilingualism, yet not all languages are represented equally in society. The situation is exacerbated by the influx of heritage languages and English through migration and globalization processes which challenge the traditional education system. This study is the first to investigate how schools in Grisons, Fribourg, and Zurich negotiate neoliberal forces leading to a growing necessity of English, a romanticized view on national languages, and the social justice perspective of institutionalizing heritage languages. It uncovers power and legitimacy issues and showcases students' and teachers' complex identities to advocate equitable multilingual education

    Endogenous measures for contextualising large-scale social phenomena: a corpus-based method for mediated public discourse

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    This work presents an interdisciplinary methodology for developing endogenous measures of group membership through analysis of pervasive linguistic patterns in public discourse. Focusing on political discourse, this work critiques the conventional approach to the study of political participation, which is premised on decontextualised, exogenous measures to characterise groups. Considering the theoretical and empirical weaknesses of decontextualised approaches to large-scale social phenomena, this work suggests that contextualisation using endogenous measures might provide a complementary perspective to mitigate such weaknesses. This work develops a sociomaterial perspective on political participation in mediated discourse as affiliatory action performed through language. While the affiliatory function of language is often performed consciously (such as statements of identity), this work is concerned with unconscious features (such as patterns in lexis and grammar). This work argues that pervasive patterns in such features that emerge through socialisation are resistant to change and manipulation, and thus might serve as endogenous measures of sociopolitical contexts, and thus of groups. In terms of method, the work takes a corpus-based approach to the analysis of data from the Twitter messaging service whereby patterns in users’ speech are examined statistically in order to trace potential community membership. The method is applied in the US state of Michigan during the second half of 2018—6 November having been the date of midterm (i.e. non-Presidential) elections in the United States. The corpus is assembled from the original posts of 5,889 users, who are nominally geolocalised to 417 municipalities. These users are clustered according to pervasive language features. Comparing the linguistic clusters according to the municipalities they represent finds that there are regular sociodemographic differentials across clusters. This is understood as an indication of social structure, suggesting that endogenous measures derived from pervasive patterns in language may indeed offer a complementary, contextualised perspective on large-scale social phenomena

    Ab Initio Language Teaching in British Higher Education

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    Drawing extensively on the expertise of teachers of German in universities across the UK, this volume offers an overview of recent trends, new pedagogical approaches and practical guidance for teaching at beginners level in the higher education classroom. At a time when entries for UK school exams in modern foreign languages are decreasing, this book serves the urgent need for research and guidance on ab initio learning and teaching in HE. Using the example of teaching German, it offers theoretical reflections on teaching ab initio and practice-oriented approaches that will be useful for teachers of both German and other languages in higher education. The first chapters assess the role of ab initio provision within the wider context of modern languages departments and language centres. They are followed by sections on teaching methods and innovative approaches in the ab initio classroom that include chapters on the use of music, textbook evaluation, the effective use of a flipped classroom and the contribution of language apps. Finally, the book focuses on the learner in the ab initio context and explores issues around autonomy and learner strengths. The whole builds into a theoretically grounded guide that sketches out perspectives for teaching and learning ab initio languages that will benefit current and future generations of students

    Distribution of distributivity in syntax and discourse

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    In this thesis, I will explore the semantics of overt distributors and investigate how it interfaces with syntax and discourse. The main claims are as follows. (1) a. Syntax-semantics interface: Denotations of quantifiers over individuals are type-ambiguous with respect to their restrictor NP, while denotations of quantifiers over situations are constant across different syntactic positions. b. Semantics-discourse interface: Overt distributors are classified into two types: one partitions variable assignments and the other partitions situations. As a case study, I discuss two overt distributors in Japanese, “sorezore” and “zutsu.” As for the first thesis, I will propose that quantifiers over individuals in Japanese has several type-variants which differ in (i) whether its restrictor NP occurs local to it or nonlocal to it, and (ii) whether its restrictor NP is predicative or argumental. Furthermore, I claim that idiosyncratic properties of quantifiers over individuals are also related with this variation with respect to the restrictor update. On the other hand, quantifiers over situations do not need a set of individuals for its restrictor and do not take a restrictor NP. Accordingly, they are not type-ambiguous and have the same denotation at the prenominal position and the floating position. Their interpretive difference comes from an independent difference between nominal predicates and verbal predicatess with respect to applicability of type-shifting principles and insertablity of situation pronouns. As for the second thesis, I claim that the semantic difference between “sorezore” and “zutsu” are best understood from the perspective of anaphoricity in dynamic semantics versus uniqueness requirement in situation semantics. “Sorezore” is anaphoric and partitions variable assignment, but “zutsu” involves uniqueness presupposition and partitions situations. Accordingly, this suggests that there are two types of overt distributors. The upshot is anaphoricity and uniqueness are two basic strategies to pick up an individual from the context because they respectively rely on two types of information content stored in the context, namely the anaphoric content and the propositional content. Thus, the dichotomy in overt distributivity can be taken as a reflection of the bipartite structure of the discourse context

    Power, Gender, and Trust in Experiences of Pediatric Emergency Physician Teleconsultation and Maternal Antenatal Anxiety in Pakistan

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    Background: In Pakistan, innovative strategies for improving access to health care, such as telemedicine (TM) and task shifting, are growing rapidly to address critical gaps in maternal and child health (MCH). Qualitative studies of social and contextual factors can help improve the development or implementation of such interventions. Objectives: This dissertation closely examines constructs of power, gender, and trust in the contexts of two populations: (1) pediatric emergency medicine (PEM) providers in a novel TM program applying synchronous expert teleconsultation to improve quality of care, and (2) pregnant women with experiences of anxiety informing the content of a psychological intervention by non-specialists. Methods: Manuscript one uses the TM Theory of Use framework to thematically analyze 20 in-depth interviews covering experiences or perspectives of doctors, nurses, and TM program administrators, while Manuscript two draws on conversation analysis methods to examine transcripts of 88 PEM teleconsultations. Manuscript three is a secondary analysis applying a women’s empowerment framework to formative research interviews on sources and mitigators of antenatal anxiety in 19 symptomatic women. Data for the qualitative TM program evaluation were collected from October 2019 to January 2020 at Sindh government hospitals, while formative research interviews on antenatal anxiety were conducted between September 2017 and August 2018 at Holy Family Hospital in Rawalpindi. Results: Perceived levels of asymmetric power and mutual trust in TM produced widely divergent and conflicting theories of use among PEM providers, while some gender-based opportunities in TM contributed to emergent social functions beyond its intended aims. Although teleconsultants accounted for a disproportionate share of asking questions and controlling topic, closer examination revealed strategic ambiguity and reciprocity as means of negotiating power and building trust in TM-mediated clinical discourse, particularly by women teleconsultants. For antenatal anxiety, gender norms and women’s disempowerment were key contextual factors contributing to women’s symptoms and limiting pregnancy-related agency and available coping strategies. Conclusion: Efforts to expand access to high quality care for mothers and children must include studies of context, whether the sociotechnical context of TM innovations or the cultural context of psychosocial interventions, to understand associated opportunities, constraints, successes, and failures in improving MCH

    Suffering in Babylon: Ludlul bēl nēmeqi and the scholars, ancient and modern

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    Suffering in Babylon comprises a series of studies on Ludlul bēl nēmeqi. Part One examines the modern scholarship surrounding the poem’s textual reconstruction and translation. Ludlul exists today as a composite text, pieced together over the last 180 years from dozens of cuneiform tablets and fragments from various archaeological sites. With these disparate sources, Assyriologists have reconstructed three quarters of the poem’s original text, which is here translated anew with extensive epigraphic and philological notes. Part Two explores the historical contexts of the poem and its reception among first-millennium scribes. Whether the poem’s protagonist is the historical Ć ubĆĄi-meĆĄrĂȘ-Ć akkan or not, his experiences as described in the poem provide insight into the worldview and concerns of the ancient scholars among whom the poem’s author was counted, likely from the ranks of the exorcists. The protagonist’s experience with divine revelation sheds light on those scholars’ divinatory worldview. The anatomical and pathological vocabulary used to describe his suffering compares well to the vocabulary in exorcism texts. The ritual failures he experiences reflect the poem’s institutional agenda. And the structure and language of his first person account shows intertextual connections with incantation prayers, a genre distinctive to exorcism. The poem’s subsequent incorporation into various scribal curricula and tablet collections demonstrates the poem’s cultural stature among first-millennium scribes, who wrote a commentary on Ludlul and used the text in the creation of others. Part Three offers a comparative study that bridges the ancient and modern scholarly horizons. Drawing on both ancient and modern scholarship, it compares the protagonist’s experience of the alĂ» demon with the clinical condition known today as sleep paralysis. The book’s underlying goal is to illustrate the potential of a multi-perspectival approach to Akkadian literature that acknowledges the contexts of both ancient and modern scholars involved in producing meaningful readings of this ancient literary gem

    Procedures as Programs: Hierarchical Control of Situated Agents through Natural Language

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    When humans conceive how to perform a particular task, they do so hierarchically: splitting higher-level tasks into smaller sub-tasks. However, in the literature on natural language (NL) command of situated agents, most works have treated the procedures to be executed as flat sequences of simple actions, or any hierarchies of procedures have been shallow at best. In this paper, we propose a formalism of procedures as programs, a powerful yet intuitive method of representing hierarchical procedural knowledge for agent command and control. We further propose a modeling paradigm of hierarchical modular networks, which consist of a planner and reactors that convert NL intents to predictions of executable programs and probe the environment for information necessary to complete the program execution. We instantiate this framework on the IQA and ALFRED datasets for NL instruction following. Our model outperforms reactive baselines by a large margin on both datasets. We also demonstrate that our framework is more data-efficient, and that it allows for fast iterative development
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