457 research outputs found

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    Essays on monetary policy

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    This is a summary of the four chapters that comprise this D.Phil. thesis.1 This thesis examines two major aspects of policy. The first two chapters examine monetary policy communication. The second two examine the causes and consequences of a time-varying reaction function of the central bank. 1. Central Bank Communication and Higher Moments In this first chapter, I investigate which parts of central bank communication affect the higher moments of expectations embedded in financial market pricing. Much of the literature on central bank communication has focused on how communication impacts the conditional expected mean of future policy. But this chapter asks how central bank communication affects the second and third moments of the financial market’s perceived distribution of future policy decisions. I use high frequency changes in option-prices around Bank of England communications to show that communication affects higher moments of the distribution of expectations. I find that the relevant communication in the case of the Bank of England is primarily confined to the information contained in the Q&A and Statement, rather than the longer Inflation Report. 2. Mark My Words: The Transmission of Central Bank Communication to the General Public via the Print Media In the second chapter, jointly with James Brookes, I ask how central banks can change their communication in order to receive greater newspaper coverage, if that is indeed an objective of theirs. We use computational linguistics combined with an event-study methodology to measure the extent of news coverage a central bank communication receives, and the textual features that might cause a communication to be more (or less) likely to be considered newsworthy. We consider the case of the Bank of England, and estimate the relationship between news coverage and central bank communication implied by our model. We find that the interaction between the state of the economy and the way in which the Bank of England writes its communication is important for determining news coverage. We provide concrete suggestions for ways in which central bank communication can increase its news coverage by improving readability in line with our results. 3. Uncertainty and Time-varying Monetary Policy In the third chapter, together with Michael McMahon, I investigate the links between uncertainty and the reaction function of the Federal Reserve. US macroeconomic evidence points to higher economic volatility being positively correlated with more aggressive monetary policy responses. This represents a challenge for “good policy” explanations of the Great Moderation which map a more aggressive monetary response to reduced volatility. While some models of monetary policy under uncertainty can match this comovement qualitatively, these models do not, on their own, account for the reaction-function changes quantitatively for reasonable changes in uncertainty. We present a number of alternative sources of uncertainty that we believe should be more prevalent in the literature on monetary policy. 4. The Element(s) of Surprise In the final chapter, together with Michael McMahon, I analyse the implications for monetary surprises of time-varying reaction functions. Monetary policy surprises are driven by several separate forces. We argue that many of the surprises in monetary policy instruments are driven by unexpected changes in the reaction function of policymakers. We show that these reaction function surprises are fundamentally different from monetary policy shocks in their effect on the economy, are likely endogenous to the state, and unable to removed using current orthogonalisation procedures. As a result monetary policy surprises should not be used to measure the effect of a monetary policy “shock” to the economy. We find evidence for reaction function surprises in the features of the high frequency asset price surprise data and in analysing the text of a major US economic forecaster. Further, we show that periods in which an estimated macro model suggests policymakers have switched reaction functions provide the majority of variation in monetary policy surprises

    Syntax-semantics interface: an algebraic model

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    We extend our formulation of Merge and Minimalism in terms of Hopf algebras to an algebraic model of a syntactic-semantic interface. We show that methods adopted in the formulation of renormalization (extraction of meaningful physical values) in theoretical physics are relevant to describe the extraction of meaning from syntactic expressions. We show how this formulation relates to computational models of semantics and we answer some recent controversies about implications for generative linguistics of the current functioning of large language models.Comment: LaTeX, 75 pages, 19 figure

    A Survey on Mapping Semi-Structured Data and Graph Data to Relational Data

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    The data produced by various services should be stored and managed in an appropriate format for gaining valuable knowledge conveniently. This leads to the emergence of various data models, including relational, semi-structured, and graph models, and so on. Considering the fact that the mature relational databases established on relational data models are still predominant in today's market, it has fueled interest in storing and processing semi-structured data and graph data in relational databases so that mature and powerful relational databases' capabilities can all be applied to these various data. In this survey, we review existing methods on mapping semi-structured data and graph data into relational tables, analyze their major features, and give a detailed classification of those methods. We also summarize the merits and demerits of each method, introduce open research challenges, and present future research directions. With this comprehensive investigation of existing methods and open problems, we hope this survey can motivate new mapping approaches through drawing lessons from eachmodel's mapping strategies, aswell as a newresearch topic - mapping multi-model data into relational tables.Peer reviewe

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    Fundamentals

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    Volume 1 establishes the foundations of this new field. It goes through all the steps from data collection, their summary and clustering, to different aspects of resource-aware learning, i.e., hardware, memory, energy, and communication awareness. Machine learning methods are inspected with respect to resource requirements and how to enhance scalability on diverse computing architectures ranging from embedded systems to large computing clusters

    ShapeCoder: Discovering Abstractions for Visual Programs from Unstructured Primitives

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    We introduce ShapeCoder, the first system capable of taking a dataset of shapes, represented with unstructured primitives, and jointly discovering (i) useful abstraction functions and (ii) programs that use these abstractions to explain the input shapes. The discovered abstractions capture common patterns (both structural and parametric) across a dataset, so that programs rewritten with these abstractions are more compact, and suppress spurious degrees of freedom. ShapeCoder improves upon previous abstraction discovery methods, finding better abstractions, for more complex inputs, under less stringent input assumptions. This is principally made possible by two methodological advancements: (a) a shape-to-program recognition network that learns to solve sub-problems and (b) the use of e-graphs, augmented with a conditional rewrite scheme, to determine when abstractions with complex parametric expressions can be applied, in a tractable manner. We evaluate ShapeCoder on multiple datasets of 3D shapes, where primitive decompositions are either parsed from manual annotations or produced by an unsupervised cuboid abstraction method. In all domains, ShapeCoder discovers a library of abstractions that captures high-level relationships, removes extraneous degrees of freedom, and achieves better dataset compression compared with alternative approaches. Finally, we investigate how programs rewritten to use discovered abstractions prove useful for downstream tasks

    Vérification efficace de systèmes à compteurs à l'aide de relaxations

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    Abstract : Counter systems are popular models used to reason about systems in various fields such as the analysis of concurrent or distributed programs and the discovery and verification of business processes. We study well-established problems on various classes of counter systems. This thesis focusses on three particular systems, namely Petri nets, which are a type of model for discrete systems with concurrent and sequential events, workflow nets, which form a subclass of Petri nets that is suited for modelling and reasoning about business processes, and continuous one-counter automata, a novel model that combines continuous semantics with one-counter automata. For Petri nets, we focus on reachability and coverability properties. We utilize directed search algorithms, using relaxations of Petri nets as heuristics, to obtain novel semi-decision algorithms for reachability and coverability, and positively evaluate a prototype implementation. For workflow nets, we focus on the problem of soundness, a well-established correctness notion for such nets. We precisely characterize the previously widely-open complexity of three variants of soundness. Based on our insights, we develop techniques to verify soundness in practice, based on reachability relaxation of Petri nets. Lastly, we introduce the novel model of continuous one-counter automata. This model is a natural variant of one-counter automata, which allows reasoning in a hybrid manner combining continuous and discrete elements. We characterize the exact complexity of the reachability problem in several variants of the model.Les systèmes à compteurs sont des modèles utilisés afin de raisonner sur les systèmes de divers domaines tels l’analyse de programmes concurrents ou distribués, et la découverte et la vérification de systèmes d’affaires. Nous étudions des problèmes bien établis de différentes classes de systèmes à compteurs. Cette thèse se penche sur trois systèmes particuliers : les réseaux de Petri, qui sont un type de modèle pour les systèmes discrets à événements concurrents et séquentiels ; les « réseaux de processus », qui forment une sous-classe des réseaux de Petri adaptée à la modélisation et au raisonnement des processus d’affaires ; les automates continus à un compteur, un nouveau modèle qui combine une sémantique continue à celles des automates à un compteur. Pour les réseaux de Petri, nous nous concentrons sur les propriétés d’accessibilité et de couverture. Nous utilisons des algorithmes de parcours de graphes, avec des relaxations de réseaux de Petri comme heuristiques, afin d’obtenir de nouveaux algorithmes de semi-décision pour l’accessibilité et la couverture, et nous évaluons positivement un prototype. Pour les «réseaux de processus», nous nous concentrons sur le problème de validité, une notion de correction bien établie pour ces réseaux. Nous caractérisions précisément la complexité calculatoire jusqu’ici largement ouverte de trois variantes du problème de validité. En nous basant sur nos résultats, nous développons des techniques pour vérifier la validité en pratique, à l’aide de relaxations d’accessibilité dans les réseaux de Petri. Enfin, nous introduisons le nouveau modèle d’automates continus à un compteur. Ce modèle est une variante naturelle des automates à un compteur, qui permet de raisonner de manière hybride en combinant des éléments continus et discrets. Nous caractérisons la complexité exacte du problème d’accessibilité dans plusieurs variantes du modèle

    Computer Aided Verification

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    This open access two-volume set LNCS 13371 and 13372 constitutes the refereed proceedings of the 34rd International Conference on Computer Aided Verification, CAV 2022, which was held in Haifa, Israel, in August 2022. The 40 full papers presented together with 9 tool papers and 2 case studies were carefully reviewed and selected from 209 submissions. The papers were organized in the following topical sections: Part I: Invited papers; formal methods for probabilistic programs; formal methods for neural networks; software Verification and model checking; hyperproperties and security; formal methods for hardware, cyber-physical, and hybrid systems. Part II: Probabilistic techniques; automata and logic; deductive verification and decision procedures; machine learning; synthesis and concurrency. This is an open access book
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