13,197 research outputs found

    Self-Supervised Learning to Prove Equivalence Between Straight-Line Programs via Rewrite Rules

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    We target the problem of automatically synthesizing proofs of semantic equivalence between two programs made of sequences of statements. We represent programs using abstract syntax trees (AST), where a given set of semantics-preserving rewrite rules can be applied on a specific AST pattern to generate a transformed and semantically equivalent program. In our system, two programs are equivalent if there exists a sequence of application of these rewrite rules that leads to rewriting one program into the other. We propose a neural network architecture based on a transformer model to generate proofs of equivalence between program pairs. The system outputs a sequence of rewrites, and the validity of the sequence is simply checked by verifying it can be applied. If no valid sequence is produced by the neural network, the system reports the programs as non-equivalent, ensuring by design no programs may be incorrectly reported as equivalent. Our system is fully implemented for a given grammar which can represent straight-line programs with function calls and multiple types. To efficiently train the system to generate such sequences, we develop an original incremental training technique, named self-supervised sample selection. We extensively study the effectiveness of this novel training approach on proofs of increasing complexity and length. Our system, S4Eq, achieves 97% proof success on a curated dataset of 10,000 pairs of equivalent programsComment: 30 pages including appendi

    Central-provincial Politics and Industrial Policy-making in the Electric Power Sector in China

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    In addition to the studies that provide meaningful insights into the complexity of technical and economic issues, increasing studies have focused on the political process of market transition in network industries such as the electric power sector. This dissertation studies the central–provincial interactions in industrial policy-making and implementation, and attempts to evaluate the roles of Chinese provinces in the market reform process of the electric power sector. Market reforms of this sector are used as an illustrative case because the new round of market reforms had achieved some significant breakthroughs in areas such as pricing reform and wholesale market trading. Other policy measures, such as the liberalization of the distribution market and cross-regional market-building, are still at a nascent stage and have only scored moderate progress. It is important to investigate why some policy areas make greater progress in market reforms than others. It is also interesting to examine the impacts of Chinese central-provincial politics on producing the different market reform outcomes. Guangdong and Xinjiang are two provinces being analyzed in this dissertation. The progress of market reforms in these two provinces showed similarities although the provinces are very different in terms of local conditions such as the stages of their economic development and energy structures. The actual reform can be understood as the outcomes of certain modes of interactions between the central and provincial actors in the context of their particular capabilities and preferences in different policy areas. This dissertation argues that market reform is more successful in policy areas where the central and provincial authorities are able to engage mainly in integrative negotiations than in areas where they engage mainly in distributive negotiations

    Improving the estimation of Cost-of-Illness in rheumatoid arthritis

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    Cost-of-illness (COI) studies measure the economic burden of a disease and estimate the maximum amount that could potentially be saved or gained if a disease were to be eradicated. Estimates of the COI can help appropriately target specific problems and policies on a disease in policy agenda setting. COI studies are particularly useful for chronic diseases that impact heavily on health expenditures and productivity loss for the whole society. It is essential for policymakers to know where costs are incurred. Consequently, appropriate interventions can be implemented and prioritised. Over the past two decades, the accumulation of coexisting long-term conditions within an individual has been confirmed as the best predictor of sustained high costs. It is now an established priority for both research and clinical practice owing to the high prevalence of coexisting diseases among patients, particularly with ageing populations. Because of this shift in how we approach chronic diseases in medical research, it is pertinent that we also think about how this impacts the way we look at COI. On the other hand, inconsistencies in the designs and methodologies that COI studies are conducted and a lack of transparency in reporting have made interpretation and comparison difficult and have limited the usefulness of results in health decision making. Variations include data sources, perspectives, cost components, and costing approaches. On the other hand, while standardisation of methodology through the implementation of guidelines is becoming increasingly important, some flexibility may be required for diseases or different contexts with unique characteristics to be adequately described. Rheumatoid arthritis (RA), as one of the most common chronic diseases, is a leading cause of work disability worldwide. Although numerous COI studies have attempted to quantify the economic burden of RA, the cost estimates vary substantially due to different methodological approaches, perspectives and settings. This thesis aims to improve the estimation of COI. To explore the differences in estimating COI, two case studies were developed in diverse contexts: Scotland and Tanzania. Both studies were complementary to each other in terms of different approaches and contexts to estimating COI. The former was in a high-income country, using secondary data analysis from a RA inception cohort linked to routinely collected health records to estimate the COI. In contrast, the latter was in a low- and middle-income country with limited treatment options. Due to the absence of routinely collected health data and the availability of screening tools for RA, a widening criterion of musculoskeletal (MSK) disorders was adopted. A context-specific questionnaire was developed to collect primary data to estimate the COI of MSK in Tanzania. This thesis confirms the need for improved estimation of COI studies. Good quality COI studies are not easy to do. Current evidence shows a lack of consistency in taking into account indirect costs, resulting in underestimating COI in RA. Moreover, indirect costs need more attention, with improvements in terms of data collection and costing approaches. Health conditions are complex and multi-dimensional, especially when the way we look at them have evolved over time. It is becoming clear that context is also an influencing factor in estimating COI. These complexities need to be considered in COI. While many systematic reviews for COI studies have urged the need to increase comparability, it is more crucial to be transparent in reporting contexts and methodological clarity, including identifying, measuring, and valuing COI

    A Framework to Support Continuous Range Queries over Multi-Attribute Trajectories

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    Desarrollo de una herramienta integral de gestión de gases de efecto invernadero para la toma de decisión contra el cambio climático a nivel regional y local en la Comunitat Valenciana

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    Tesis por compendio[ES] Actualmente, los responsables de tomar decisiones contra el cambio climático carecen de herramientas para desarrollar inventarios de emisiones de gases de efecto invernadero (GEI) con suficiente rigor científico-técnico y precisión para priorizar e invertir los recursos disponibles de manera eficiente en las medidas necesarias para luchar contra el cambio climático. Por ello, en esta tesis se expone el desarrollo de un sistema de información territorial y sectorial (SITE) para monitorear las emisiones de GEI que sirva como herramienta de gobernanza climática local y regional. SITE combina las ventajas de los enfoques metodológicos descendente o top-down (de arriba hacia abajo) y ascendente o bottom-up (de abajo hacia arriba), para lograr un enfoque híbrido innovador para contabilizar y gestionar de manera eficiente las emisiones de GEI. Por tanto, en esta tesis se definen los diferentes desarrollos metodológicos, tanto generales como específicos de sectores clave del Panel Intergubernamental de Cambio Climático (IPPC) (edificación, transporte, sector forestal, etc.), un desarrollo informático para la parte de SITE que se ejecuta del lado del servidor, que de ahora en adelante denominaremos back-end del sistema, y siete implementaciones como casos de estudio representativos, a diferentes escalas y aplicados sobre diferentes sectores. Estas implementaciones a diferentes escalas y sectores demuestran el potencial del sistema como herramienta de apoyo en la toma de decisión contra el cambio climático a nivel regional y local. Las diferentes implementaciones en casos piloto representativos, tanto a nivel regional en la Comunitat Valenciana como a nivel local en municipios grandes (València) y medianos (Quart de Poblet y Llíria) muestran el potencial de adaptación territorial y sectorial que tiene la herramienta. Las metodologías desarrolladas para los sectores específicos de tráfico rodado, edificación o sector forestal, ofrecen cuantificaciones con una resolución espacial con gran capacidad de optimizar las políticas locales y regionales. Por tanto, la herramienta cuenta con un gran potencial de escalabilidad y gran capacidad de mejora continua mediante la inclusión de nuevos enfoques metodológicos, adaptación de las metodologías a la disponibilidad de datos, metodologías concretas para sectores clave y actualización a las mejores metodologías disponibles derivadas de actividades de investigación de la comunidad científica.[CA] Actualment, els responsables de prendre decisions contra el canvi climàtic no tenen eines per aconseguir inventaris d'emissions de gasos d'efecte hivernacle (GEH) amb prou cientificotècnic rigor, precisió i integritat per invertir els recursos disponibles de manera eficient en les mesures necessàries contra el canvi climàtic. Per això, en aquesta tesis se exposa el desenvolupa un sistema d'informació territorial i sectorial (SITE) per monitoritzar les emissions de GEH com a eina de governança climàtica local i regional. Aquest sistema combina els avantatges dels enfocaments metodològics descendent o top-down (de dalt a baix) i ascendent o bottom-up (de baix a dalt), per aconseguir un enfocament híbrid innovador per comptabilitzar i gestionar de manera eficient les emissions de GEH. Per tant, en aquesta tesi doctoral es descriuen els diferents desenvolupaments metodològics, tant generals com específics de sectors clau del Panel Intergovernamental contra el Canvi Climàtic (edificació, transport, forestal, etc.), un desenvolupament informàtic per al back-end del sistema i set implementacions com a casos d'estudi representatius, a diferents escales, amb els diferents enfocaments metodològics i aplicats sobre diferents sectors. Això queda descrit en sis capítols. Aquestes implementacions a diferents escales i sectors demostren el potencial del sistema com a eina de suport en la presa de decisió contra el canvi climàtic a nivell regional i local. Les diferents implementacions en casos pilot representatius, tant a nivell regional a la Comunitat Valenciana com a nivell local en municipis grans (València) i mitjans (Quart de Poblet i Llíria,) mostren el potencial d'adaptació territorial i sectorial que té l'eina. Les metodologies desenvolupades per als sectors específics de trànsit rodat, edificació i forestal, ofereixen quantificacions amb una resolució espacial amb gran capacitat d'optimitzar les polítiques locals i regionals. Per tant, l'eina compta amb un gran potencial d'escalabilitat i gran capacitat de millora contínua mitjançant la inclusió de nous enfocaments metodològics, adaptació de les metodologies a la disponibilitat de dades, metodologies concretes per a sectors clau, i actualització a les millors metodologies disponibles derivades de activitats de investigació de la comunitat científica.[EN] Currently, regional and local decision-makers lack of tools to achieve greenhouse gases (GHG) emissions inventories with enough rigor, accuracy and completeness in order to prioritize available resources efficiently against climate change. Thus, in this thesis the development of a territorial and sectoral information system (SITE) to monitor GHG emissions as a local and regional climate governance tool is exposed. This system combines the advantages of both, top-down and bottom-up approaches, to achieve an innovative hybrid approach to account and manage efficiently GHG emissions. Furthermore, this thesis defines the methodologies developed, a computer proposal for the back-end of the system and seven implementations as representative case studies at different scales (local and regional level), with the different methodological approaches and applied to different sectors. Thus, these implementations demonstrate the potential of the system as decision-making tool against climate change at the regional and local level as climate governance tool. The different implementations in representative pilot cases, both at the regional level in the Valencian Community and at the local level in large (Valencia) and medium-sized municipalities (Quart de Poblet and Llíria) demonstrate the potential for territorial and sectoral adaptation of the system developed. The methodologies developed for the specific sectors of road transport, building and forestry, offer quantifications with a spatial resolution with a great capacity to optimize local and regional policies. Therefore, the tool has a great potential for scalability and a great capacity for continuous improvement through the inclusion of new methodological approaches, adapting the methodologies to the availability of data, specific methodologies for key sectors, and updating to the best methodologies available in the scientific community.Lorenzo Sáez, E. (2022). Desarrollo de una herramienta integral de gestión de gases de efecto invernadero para la toma de decisión contra el cambio climático a nivel regional y local en la Comunitat Valenciana [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/181662TESISCompendi

    DIGITAL PROCTORING IN HIGHER EDUCATION: A SYSTEMATIC LITERATURE REVIEW

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    To improve the academic integrity of online examination, digital proctoring systems have been implemented in higher education worldwide, particularly during the COVID-19 pandemic. In this paper, we conducted a literature review of the research on digital proctoring in higher education. We found 115 relevant publications in nine databases. We applied topic modeling methods to analyze the corpus which resulted in eight topics. The review shows that the previous studies focus largely on the systems’ development, adoption of the systems, the effects of proctored online exams on students’ performance, and the legal, ethical, security, and privacy issues of digital proctoring. The annual topic trends indicate future research concerns, such as systems’ development, online programs (MOOCs) and proctoring, along with various issues of using digital proctoring. The results of the review provide useful insights as well as implications for future research on digital proctoring, a crucial process for digitalizing higher education

    Grace, Disruption and Stability: The Christian Life in the Theologies of Rowan Williams and Oliver O’Donovan

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    This thesis explores the character of the Christian life in the writings of the contemporary Anglican theologians Rowan Williams and Oliver O’Donovan. I display a set of theological contrasts that arise from their respective accounts of creation and Christology, which are amplified in their understandings of the affective shape of the Christian life. I argue that the most constructive response to these differences is not to be found at the level of theological synthesis. Indeed, I argue for a certain kind of theological irresolution in response to these themes. When taken together, these thinkers’ works display a set of dissonant, yet equally necessary aspects of the Christian vision which are fruitful for wise Christian living. The dominant motif of Williams’ writings is the disruptive character of God’s transforming work in human lives, as each person grows into conformity with the crucified and risen Christ. In his vision, the Christian life involves a journey of being drawn by the Spirit into the endless abundance of God. It is a life marked by continual repentance and renewal, and learning to see Christ in new ways at the centre of all things. O’Donovan’s account of the Christian gospel focusses on the centrality of creation as a stable order, assured and restored through Christ’s resurrection. The Christian life entails seeking and joyously finding oneself within this good order of God’s making and redeeming. The gospel offers an assured place to survey one’s life, and a stable foundation from which to live well. I argue that these thinker’s works, when taken together, can nourish an account of Christian wisdom and discernment which brings to the foreground, in different ways and at different times, the disruptive and stabilising aspects of the Christian gospel, for the sake of faithful and flourishing Christian livin

    The crisis of cultural authority in museums : contesting human remains in the collections of Britain

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    Museums in Britain have displayed and researched human remains since the eighteenth century. However, in the last two decades human remains in collections have become subject to claims and controversies. Firstly, human remains associated with acquisition during the colonial period have become increasingly difficult to retain and have been transfered to culturally affiliated overseas indigenous groups. Secondly, a group of British Pagans have formed to make claims on ancient human remains in collections. Thirdly, human remains that are not requested by any community group, and of all ages, have become the focus of concerns expressed about their treatment by members of the profession. A discourse arguing for 'respect' has emerged, which argues that all human remains should be treated with new care. The claims made on human remains have been vigourously but differentially contested by members of the sector, who consider the human remains to be unique research objects. This thesis charts the influences at play on the contestation over human remains and examines its construction. The academic literature tends to understand changes to museums as a result of external factors. This thesis argues that this problem is influenced by a crisis of legitimacy and establishes that there are strong internal influences. Through a weak social constructionist approach I demonstrate that the issue has been promoted by influential members of the sector as part of a broader attempt to distance themselves from their foundational role, as a consequence of a crisis of cultural authority stimulated by external and internal factors. The symbolic character of human remains in locating this problem is informed by the unique properties of dead bodies and is influenced by the significance of the body as a scientific object; its association with identity work and as a site of political struggle, in the high modem period

    Statistical Learning for Gene Expression Biomarker Detection in Neurodegenerative Diseases

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    In this work, statistical learning approaches are used to detect biomarkers for neurodegenerative diseases (NDs). NDs are becoming increasingly prevalent as populations age, making understanding of disease and identification of biomarkers progressively important for facilitating early diagnosis and the screening of individuals for clinical trials. Advancements in gene expression profiling has enabled the exploration of disease biomarkers at an unprecedented scale. The work presented here demonstrates the value of gene expression data in understanding the underlying processes and detection of biomarkers of NDs. The value of novel approaches to previously collected -omics data is shown and it is demonstrated that new therapeutic targets can be identified. Additionally, the importance of meta-analysis to improve power of multiple small studies is demonstrated. The value of blood transcriptomics data is shown in applications to researching NDs to understand underlying processes using network analysis and a novel hub detection method. Finally, after demonstrating the value of blood gene expression data for investigating NDs, a combination of feature selection and classification algorithms were used to identify novel accurate biomarker signatures for the diagnosis and prognosis of Parkinson’s disease (PD) and Alzheimer’s disease (AD). Additionally, the use of feature pools based on previous knowledge of disease and the viability of neural networks in dimensionality reduction and biomarker detection is demonstrated and discussed. In summary, gene expression data is shown to be valuable for the investigation of ND and novel gene biomarker signatures for the diagnosis and prognosis of PD and AD
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