1,207 research outputs found
Abstracting Gradual References (SCICO Journal-first)
No full textGradual typing is an effective approach to integrate static and dynamic typing, which supports the smooth transition between both extremes via the (programmer-controlled) precision of type annotations [Jeremy Siek and Walid Taha, 2006; Siek et al., 2015]. Imprecision is normally introduced via the unknown type ?, e.g. function type Int → Bool is more precise than ? → ?, and both more precise than ?. Gradual typing relates types of different precision using consistent type relations, such as type consistency (resp. consistent subtyping), the gradual counterpart of type equality (resp. subtyping). For instance, ? → Int is consistent with Bool → ?. This approach has been applied in a number of settings, such as objects [Jeremy Siek and Walid Taha, 2007], subtyping [Jeremy Siek and Walid Taha, 2007; Ronald Garcia et al., 2016], effects [Bañados Schwerter et al., 2014; Bañados Schwerter et al., 2016], ownership [Ilya Sergey and Dave Clarke, 2012], typestates [Roger Wolff et al., 2011; Ronald Garcia et al., 2014], information-flow typing [Tim Disney and Cormac Flanagan, 2011; Luminous Fennell and Peter Thiemann, 2013; Matías Toro et al., 2018], session types [Igarashi et al., 2017], refinements [Nico Lehmann and {É}ric Tanter, 2017], set-theoretic types [Castagna and Lanvin, 2017], Hoare logic [Johannes Bader et al., 2018], parametric polymorphism [Amal Ahmed et al., 2011; Ahmed et al., 2017; Ina and Igarashi, 2011; Igarashi et al., 2017; Ningning Xie et al., 2018; Matías Toro et al., 2019], and references [Jeremy Siek and Walid Taha, 2006; Herman et al., 2010; Siek et al., 2015].
In particular, gradual typing for mutable references has seen the elaboration of various possible semantics: invariant references [Jeremy Siek and Walid Taha, 2006], guarded references [Herman et al., 2010], monotonic references [Siek et al., 2015], and permissive references [Siek et al., 2015]. Invariant references are a form of references where reference types are invariant with respect to type consistency. Guarded references admit variance thanks to systematic runtime checks on reference reads and writes; the runtime type of an allocated cell never changes during execution. Guarded references have been formulated in a space-efficient coercion calculus, which ensures that gradual programs do not accumulate unbounded pending checks during execution. Hereafter, we refer to this language as HCC. Monotonic references favor efficiency over flexibility by only allowing reference cells to vary towards more precise types. This allows reference operations in statically-typed regions to safely proceed without any runtime checks. Permissive references are the most flexible approach, in which reference cells can be initialized and updated to any value of any type at any time.
These four developments reflect different design decisions with respect to gradual references: is the reference type constructor variant under consistency? Can the programmer specify a precise bound on the static type of a reference, and hence on the corresponding heap cell type? Can the heap cell type evolve its precision at runtime, and if yes, how? There is obviously no absolute answer to these questions, as they reflect different tradeoffs such as in efficiency and precision. This work explores the semantics that results from the application of a systematic methodology to gradualize static type systems. Currently we can find in the literature two methodologies to gradualize statically-typed languages: Abstracting Gradual Typing (AGT) [Ronald Garcia et al., 2016], and the Gradualizer [Matteo Cimini and Jeremy Siek, 2016]. In this work, we consider the AGT methodology as it naturally scales to auxiliary structures such as a mutable heap.
The AGT methodology helps to systematically construct gradually-typed languages by using abstract interpretation [Cousot and Cousot, 1977] at the type level. In brief, AGT interprets gradual types as an abstraction of sets of possible static types, formally captured through a Galois connection. The static semantics of a gradual language are then derived by lifting the semantics of a statically-typed language through this connection, and the dynamic semantics follow by Curry-Howard from proof normalization of the type safety argument. The AGT methodology has been shown to be effective in many contexts: records and subtyping [Ronald Garcia et al., 2016], type-and-effects [Bañados Schwerter et al., 2014; Bañados Schwerter et al., 2016], refinement types [Nico Lehmann and Éric Tanter, 2017; Niki Vazou et al., 2018], set-theoretic and union types [Castagna and Lanvin, 2017; Matías Toro and Éric Tanter, 2017], information-flow typing [Matías Toro et al., 2018], and parametric polymorphism [Matías Toro et al., 2019]. However, this methodology has never been applied to mutable references in isolation. Although Toro et al. [Matías Toro et al., 2018] apply AGT to a language with references, they only gradualize security levels of types (e.g. Ref Int_?), not whole types (e.g. Ref ? is not supported). In this article we answer the following open questions: Which semantics for gradually-type references follows by systematically applying AGT? Does AGT justify one of the existing approaches, or does it suggest yet another design? Can we recover other semantics for gradual references, if yes, how?
This article first reviews the different existing gradual approaches to mutable references through examples. It then presents the semantics for gradual references that is obtained by applying AGT, and how to accommodate the other semantics. More specifically, this work makes the following contributions:
- We present λ_REF~, a gradual language with support for mutable references. We derive λ_REF~ by applying the AGT methodology to a fully-static simple language with mutable references called λ_REF. This is the first application of AGT that focuses on gradually-typed mutable references.
- We prove that λ_REF~ satisfies the gradual guarantee of Siek et al. [Siek et al., 2015]. We also present the first formal statement and proof of the conservative extension of the dynamic semantics of the static language [Siek et al., 2015], for a gradual language derived using AGT.
- We prove that the derived language, λ_REF~, corresponds to the semantics of guarded references from HCC. Formally, given a λ_REF~ term and its compilation to HCC^+ (an adapted version of HCC extended with conditionals and binary operations) we prove that both terms are bisimilar, and that consequently they either both terminate, both fail, or both diverge.
- We observe that λ_REF~ and HCC^+ differ in the order of combination of runtime checks. As a result, HCC is space efficient whereas λ_REF~ is not: we can write programs in λ_REF~ that may accumulate an unbounded number of checks. We formalize the changes needed in the dynamic semantics of λ_REF~ to achieve space efficiency. This technique to recover space efficiency is in fact independent from mutable references, and is therefore applicable to other gradual languages derived with AGT.
- We formally describe how to support other gradual reference semantics in λ_REF~ by presenting λ_REF~^, an extension that additionally supports both permissive and monotonic references. Finally, we prove for the first time that monotonic references satisfy the dynamic gradual guarantee, a non-trivial result that requires careful consideration of updates to the store.
Additionally, we implemented λ_REF~ as an interactive prototype that displays both typing derivations and reduction traces. All the examples mentioned in this paper are readily available in the online prototype available at https://pleiad.cl/grefs.
As a result, this paper sheds further light on the design space of gradual languages with mutable references and contributes to deepening the understanding of the AGT methodology
El diablo dijo… “¡acción!”: Hellboy en el laberinto Del Toro
No full textDirected by Guillermo del Toro from the comic-book created by Mike Mignola, Hellboy (2004) is the most cherished film by the author of Pan’s Labyrinth (2006). This paper analyses the film’s literary debts –gothic narrative, Lovecraft, Machen, american pulp serials– as well as filmic homages and borrows –Spielberg, Lucas, 50’s science fiction, B movies, cartoons, manga, etc.– that enriches the deltorian imaginery
Defying the law, negotiating change The Futanke’s opposition to the national ban on FGM in Senegal
No full textThis thesis is concerned with the politics of the preservation and ‘abandonment’ of female circumcision in Fouta Toro, Senegal. The focal point of analysis is the overt opposition to the law criminalising female genital cutting in 1999, and development projects raising awareness about excision in human rights and reproductive health education programmes. As an ethnography of the politics around bodily practices in the light of governmental and non-governmental intervention, the thesis looks at how different interest groups justify their position towards excision. This is a timely enquiry, given the Senegalese government’s ‘acceleration programme of the complete abandonment of excision by 2015’ and some Futanke leaders’ non-compliance with, and opposition to this intervention.
After providing details about ‘the ban’ on ‘female genital mutilation’ in Senegal and a critical reflection on the events that are seen to have led to the call for this ban, I carefully disentangle what ‘the opposition to the law’ is and who disagrees with ‘the abandonment’ of the practice in Fouta Toro. The central part of the thesis is guided by an analysis of how excision is embedded in constructions of personhood, sociality and ethnic identity, and how the body is imagined and located in this process. I show how conceptions of ethnic purity and pride are formulated in terms of fear about a ‘loss of culture’ and ‘foreign invasion’ which nourishes discourses of opposition to the law and non-governmental intervention. Others use ‘human rights’ associated with non-governmental organisations and the state as a vehicle to express their views against excision and those who oppose its criminalisation. I examine how idioms like ‘the state’, ‘human rights’ and ‘Futanke way of life’ feature in discourses around the ban of excision in Fouta Toro, and how respectability and honour are maintained through competing representations of the female body as a site of morality. Some claim the female body – a reproducer of cultural identities – with reference to duties through kin obligations, others with reference to ‘human rights’ and ‘the state’.
Based on 15 months’ ethnographic fieldwork in Fouta Toro and nine years working in and researching the impact of development in Senegal, this dissertation contributes to scholarship on Fouta Toro and indicates how governmental and non-governmental intervention stirs up the caste-related power structures of a society led by the Tooroɓɓe since the Islamic revolution in the 18th century. It shows how the female body is located as a site of morality, key to the reproduction of cultural identities
Propuesta para la implementación de un doble factor de autenticación físico para fortalecer el control de acceso en la sede del ministerio de tecnologías de la información y las comunicaciones (Mintic), conocida como el Edificio Murillo Toro
No full textLa seguridad de la información es esencial en un mundo digital interconectado, especialmente en sistemas críticos que manejan datos sensibles. Las entidades públicas deben proteger sus instalaciones y activos, utilizando medidas como el control de acceso. En este contexto, se propone implementar un sistema de doble factor de autenticación física en el edificio Murillo Toro del Ministerio de Tecnologías de la Información y las Comunicaciones. Esto fortalecerá el control de acceso y la seguridad al combinar dos elementos de verificación, reduciendo el riesgo de accesos no autorizados. Esta tecnología ha demostrado ser efectiva en la prevención de intrusiones. La implementación cumplirá con normas como la ISO 27001 y requisitos legales, demostrando el compromiso con la seguridad y la protección de datos personales. En resumen, el proyecto refuerza la seguridad física, el cumplimiento normativo y la protección de activos e información confidencial
Househould goods stock improvement procedures in Toro Ltd
No full textŠī darba mērķis ir izpētīt uzņēmuma SIA “Toro” krājumu novērtēšanas un uzskaites metodes, kā arī tā krājumu apriti, to uzraudzību un noliktavas darbības procesus. Darba autore ir izstrādājusi darbu trīs nodaļās, kurās ietverta krājumu teorētiskais apkopoums pēc speciālās literatūras un likumiem, novērtētas pielietojamās krājumu uzskaites metodes SIA “Toro”, kā arī analizēta uzņēmuma noliktavas darba organizēšana un inventarizācija. Pēc SIA “Toro” izpētes, ir konstatētas nepilnības noliktavas darba procesā, tāpēc ir izstrādāti priekšlikumi noliktavas darba un preču piegādes uzlabošanai. Atslēgvārdi: apgrozāmie līdzekļi, krājumu uzskaites metodes, krājumi, inventarizācija, noliktava.The aim of this paper is to analyse the company "Toro" stock valuation and accounting methods, as well as the movement of inventory, monitoring and warehouse operational processes. The author has developed a work in three chapters, which include theoretical inventory research after literature and laws, assessed inventory accounting methods in Toro Ltd., also analysis of the company's warehouse work organization and inventory. According to Toro Ltd. research has identified shortcomings in warehouse work process author made suggestions for warehouse labor and product delivery improvement. Keywords: current assets, asset keeping methods, assets, inventory, warehouse
Spontaneous ATM gene reversion in A-T iPSC to produce an isogenic cell line
No full textA spontaneously reverted iPSC line was identified from an A-T subject with heterozygous ATM truncation mutations. The reverted iPSC line expressed ATM protein and was capable of radiation-induced phosphorylation of CHK2 and H2A.X. Genome-wide SNP analysis confirmed a match to source T-cells and also to a distinct, non-reverted iPSC line from the same subject. Rearranged T-cell receptor sequences predict that the iPSC culture originated as several independently reprogrammed cells that resolved into a single major clone, suggesting that gene correction likely occurred early in the reprogramming process. Gene expression analysis comparing ATM-/- iPSC lines to unrelated ATM+/- cells identifies a large number of differences but comparing only the isogenic pair of A-T iPSC lines reveals that the primary pathway affected by loss of ATM is a diminished expression of p53-related mRNAs. Gene reversion in culture, while likely a rare event, provided a novel, reverted cell line for studying ATM function.Peer reviewe
Sahuarita/ El Toro corridor study : final report
No full textabstract: The Sahuarita/El Toro Corridor Study is a joint effort by the Town of Sahuarita and the Arizona Department of Transportation. The purpose of the study is to assess the feasibility of a transportation corridor that will provide adequate capacity for the potential future growth of the Town of Sahuarita and surrounding areas as well as increase local and regional connectivity in Pima County. The study is being funded by Federal Highway Administration’s State Planning and Research Program and administered through ADOT’s Multimodal Planning Division. In the completed Town of Sahuarita Transportation Study, it was recommended that El Toro Rd be constructed as a six-lane parkway to alleviate the severely congested principal thoroughfares due to the future growth identified in that study
Memoria personal e Historia nacional: conversando con Suso de Toro - Memoria personale e Storia nazionale: conversazione con Suso de Toro
No full textIn the following interview, Suso de Toro recalls his career as a novelist from the beginnings to the present day. He focuses on the evolution of his narrative style against the backdrop of the recent Spanish historical context. The author concentrates on those works that characterize him as an engaged writer: Non volvas (2000), Home sen nome (2006), Sete palabras (2010) e Somnámbulos (2014)
TD1-P01779 - Unea & John Gorogo & Eno Eno, Kopi (Tom Gavi's mother); Albert Toro
No full textSide 1 -- 1. Unea & John Gorogo (Vanapa) (& family & James Umebo'i in background) on Jack Tanner -- 2. Eno Eno (Manumanu) on same. -- Side 2 -- 1. Kopi (Tom Gavi's' (Jr) mother) (000-310) -- 2. Albert Toro, author of 'Sugar Days' (NBC Radio Play) (316-451). Interview with Albert Toro -- Location: Papua New Guinea, place unspecified -- Date: Monday, 17 September 1979 -- Transcript is at TD1-P01779-B.rtf/pdf. Language as given: Englis
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