1,903 research outputs found

    The Sparse Abstract Machine

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    We propose the Sparse Abstract Machine (SAM), an abstract machine model for targeting sparse tensor algebra to reconfigurable and fixed-function spatial dataflow accelerators. SAM defines a streaming dataflow abstraction with sparse primitives that encompass a large space of scheduled tensor algebra expressions. SAM dataflow graphs naturally separate tensor formats from algorithms and are expressive enough to incorporate arbitrary iteration orderings and many hardware-specific optimizations. We also present Custard, a compiler from a high-level language to SAM that demonstrates SAM's usefulness as an intermediate representation. We automatically bind from SAM to a streaming dataflow simulator. We evaluate the generality and extensibility of SAM, explore the performance space of sparse tensor algebra optimizations using SAM, and show SAM's ability to represent dataflow hardware.Comment: 18 pages, 17 figures, 3 table

    Bridging Two Worlds

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    The rise of China and India could be the most important political development of the twenty-first century. What will the foreign policies of China and India look like in the future? What should they look like? And what can each country learn from the other? Bridging Two Worlds gathers a coterie of experts in the field, analyzing profound political thinkers from these ancient regions whose theories of interstate relations set the terms for the debates today. This volume is the first work of its kind and is essential reading for anyone interested in the growth of China and India and what it means for the rest of the world. “This brilliant volume shines a light on the two great civilizations that will once again drive world history. No volume could be more timely, more relevant, and more needed than this one.” — KISHORE MAHBUBANI, Distinguished Fellow, Asia Research Institute, NUS, and author of The Asian 21st Century “With the recently elevated economic and political power of China and the great potential of India in the twenty-first century, interdisciplinary dialogue and engagement such as is found in this book is necessary for contemporary debates in political theory and international relations.” — KUIYI SHEN, Professor of Asian Art History, Theory, and Criticism, University of California, San Diego

    Adding hygiene to gambit scheme

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    Le langage de programmation Scheme est reconnu pour son puissant système de macro-transformations. La représentation du code source d'un programme, sous forme de données manipulables par le langage, permet aux programmeurs de modifier directement l'arbre de syntaxe abstraite sous-jacent. Les macro-transformations utilisent une syntaxe similaire aux procédures régulières mais, elles définissent plutôt des procédures à exécuter lors de la phase de compilation. Ces procédures retournent une représentation sous forme d'arbre de syntaxe abstraite qui devra être substitué à l'emplacement de l'appel du transformateur. Les procédures exécutées durant la phase de compilation profitent de la même puissance que celles exécutées durant de la phase d'évaluation. Avec ce genre de système de macro-transformations, un programmeur peut créer des règles de syntaxe spécialisées sans aucun coût additionnel en performance: ces extensions syntactiques permettent l'abstraction de code sans les coûts d'exécution habituels reliés à la création d'une fermeture sur le tas. Cette représentation pour le code source de Scheme provient directement du langage de programmation Lisp. Le code source est représenté sous forme de listes manipulables de symboles, ou bien de listes contenants d'autres listes: une structure appelée S-expression. Cependant, avec cette approche simpliste, des conflits de noms peuvent apparaître. En effet, l'association référée par un certain identifiant est déterminée exclusivement par le contexte lexical de celui-ci. En déplaçant un identifiant dans l'arbre de syntaxe abstraite, il est possible que cet identifiant se retrouve dans un contexte lexical contenant une certaine association pour un identifiant du même nom. Dans de tels cas, l'identifiant déplacé pourrait ne plus référer à l'association attendue, puisque cette seconde association pourrait avoir prévalence sur la première. L'assurance de transparence référentielle est alors perdue. En conséquence, le choix de nom pour les identifiants vient maintenant influencer directement le comportement du programme, générant des erreurs difficiles à comprendre. Les conflits de noms peuvent être corrigés manuellement dans le code en utilisant, par exemple, des noms d'identifiants uniques. La préservation automatique de la transparence référentielle se nomme hygiène, une notion qui a été beaucoup étudiée dans le contexte des langages de la famille Lisp. La dernière version du Scheme revised report, utilisée comme spécification pour le langage, étend ce dernier avec un support pour les macro-transformations hygiéniques. Jusqu'à maintenant, l'implémentation Gambit de Scheme ne fournissait pas de tel système à sa base. Comme contribution, nous avons ré-implémenter le système de macro de Gambit pour supporter les macro-transformations hygiéniques au plus bas niveau de l'implémentation. L'algorithme choisi se base sur l'algorithme set of scopes implémenté dans le langage Racket et créé par Matthew Flatt. Le langage Racket s'est grandement inspiré du langage Scheme mais, diverge sur plusieurs fonctionnalités importantes. L'une de ces différences est le puissant système de macro-transformation sur lequel Racket base la majorité de ses primitives. Dans ce contexte, l'algorithme a donc été testé de façon robuste. Dans cette thèse, nous donnerons un aperçu du langage Scheme et de sa syntaxe. Nous énoncerons le problème d'hygiène et décrirons différentes stratégies utilisées pour le résoudre. Nous justifierons par la suite notre choix d'algorithme et fourniront une définition formelle. Finalement, nous présenterons une analyse de la validité et de la performance du compilateur en comparant la version originale de Gambit avec notre version supportant l'hygiène.The Scheme programming language is known for its powerful macro system. With Scheme source code represented as actual Scheme data, macro transformations allow the programmer, using that data, to act directly on the underlying abstract syntax tree. Macro transformations use a similar syntax to regular procedures but, they define procedures meant to be executed at compile time. Those procedures return an abstract syntax tree representation to be substituted at the transformer's call location. Procedures executed at compile-time use the same language power as run-time procedures. With the macro system, the programmer can create specialized syntax rules without additional performance costs. This also allows for code abstractions without the expected run-time cost of closure creations. Scheme's representation of source code using values inherits that virtue from the Lisp programming language. Source code is represented as a list of symbols, or lists of other lists: a structure coined S-expressions. However, with this simplistic approach, accidental name clashes can occur. The binding to which an identifier refers to is determined by the lexical context of that identifier. By moving an identifier around in the abstract syntax tree, it can be caught within the lexical context of another binding definition with the same name. This can cause unexpected behavior for programmers as the choice of names can create substantial changes in the program. Accidental name clashes can be manually fixed in the code, using name obfuscation, for instance. However, the programmer becomes responsible for the program's safety. The automatic preservation of referential transparency is called hygiene and was thoroughly studied in the context of lambda calculus and Lisp-like languages. The latest Scheme revised report, used as a specification for the language, extend the language with hygienic macro transformations. Up to this point, the Gambit Scheme implementation wasn't providing a built-in hygienic macro system. As a contribution, we re-implemented Gambit's macro system to support hygienic transformations at its core. The algorithm we chose is based on the set of scopes algorithm, implemented in the Racket language by Matthew Flatt. The Racket language is heavily based on Scheme but, diverges on some core features. One key aspect of the Racket language is its extensive hygienic syntactic macro system, on which most core features are built on: the algorithm was robustly tested in that context. In this thesis, we will give an overview of the Scheme language and its syntax. We will state the hygiene problem and describe different strategies used to enforce hygiene automatically. Our algorithmic choice is then justified and formalized. Finally, we present the original Gambit macro system and explain the changes required. We also provide a validity and performance analysis, comparing the original Gambit implementation to our new system

    SPEC5G: A Dataset for 5G Cellular Network Protocol Analysis

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    5G is the 5th generation cellular network protocol. It is the state-of-the-art global wireless standard that enables an advanced kind of network designed to connect virtually everyone and everything with increased speed and reduced latency. Therefore, its development, analysis, and security are critical. However, all approaches to the 5G protocol development and security analysis, e.g., property extraction, protocol summarization, and semantic analysis of the protocol specifications and implementations are completely manual. To reduce such manual effort, in this paper, we curate SPEC5G the first-ever public 5G dataset for NLP research. The dataset contains 3,547,586 sentences with 134M words, from 13094 cellular network specifications and 13 online websites. By leveraging large-scale pre-trained language models that have achieved state-of-the-art results on NLP tasks, we use this dataset for security-related text classification and summarization. Security-related text classification can be used to extract relevant security-related properties for protocol testing. On the other hand, summarization can help developers and practitioners understand the high level of the protocol, which is itself a daunting task. Our results show the value of our 5G-centric dataset in 5G protocol analysis automation. We believe that SPEC5G will enable a new research direction into automatic analyses for the 5G cellular network protocol and numerous related downstream tasks. Our data and code are publicly available

    Employee Engagement and Leadership in the Federal Sector

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    While levels of engagement have slightly increased, employee engagement in the U.S. federal government sector still significantly lags when compared to the private sector. When asked if organizational leaders generate high levels of motivation and commitment in the workforce, only 48% of U.S. federal government employees indicated a positive response. The purpose of this quantitative correlation study and primary research question was to determine to what extent, if any, does a relationship exist between perceptions of leadership communication and effectiveness and employee engagement in the U.S. federal government sector. The theoretical framework of this quantitative correlational study was informed by William A. Kahn’s theory of personal engagement and the public service motivation theory. An online survey was employed, and a total of 139 participants were included in this study. To test the research hypothesis, a linear regression analysis was conducted. The findings suggest that there is a significant relationship between perceptions of leadership communication and effectiveness and levels of employee engagement; public service motivation and employee engagement; and trust in leadership and employee engagement in the U.S. federal government. These findings may help contribute to positive social change as improved engagement and leadership practices may enhance productivity and increase employee effectiveness in the federal workplace

    Alexander Dallas Bache: Building the American Nation through Science and Education in the Nineteenth Century

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    Alexander Dallas Bache was the key leader of antebellum American scientists. Presuming his profession to be a herald of an integrated U.S. nation-state, Bache guided organizations such as the United States Coast Survey, then the country's largest scientific enterprise. In this analytical biography, Axel Jansen explains Bache's efforts to build and shape public institutions as a national foundation for a universalistic culture - efforts that culminated during the Civil War when Bache helped found the National Academy of Sciences as a symbol for the continued viability of an American nation

    Operatic Pasticcios in 18th-Century Europe

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    In Early Modern times, techniques of assembling, compiling and arranging pre-existing material were part of the established working methods in many arts. In the world of 18th-century opera, such practices ensured that operas could become a commercial success because the substitution or compilation of arias fitting the singer's abilities proved the best recipe for fulfilling the expectations of audiences. Known as »pasticcios« since the 18th-century, these operas have long been considered inferior patchwork. The volume collects essays that reconsider the pasticcio, contextualize it, define its preconditions, look at its material aspects and uncover its aesthetical principles

    Strategies Dental Center Leaders Use to Improve Productivity Using Onsite 3D Printing

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    Many dental centers are leveraging onsite 3D printing to increase their productivity and improve the quality of care they provide. However, dental center leaders lacking strategies to implement onsite 3D printing in their dental centers fail to take advantage of the substantial benefits of using this new technology. Grounded in the theory of disruptive innovation, the purpose of this qualitative multiple-case study was to explore strategies dental center leaders use to improve productivity using onsite 3D printing. The participants comprised five dental center leaders in the United States who successfully implemented strategies to improve productivity using onsite 3D printing. Data were collected from semistructured interviews, company websites, and publicly available information. Thematic analysis was used to analyze the data. Three themes emerged: (a) enabling technology strategy, (b) innovative business model strategy, and (c) customer demand strategy. A key recommendation includes ensuring better patient experiences with less chair time, fewer visits, and more access to care. The implications for positive social change have the potential to make affordable quality dental care available to underserved communities, facilitate new career opportunities for local communities, and contribute to the economic development of these communities
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