425 research outputs found
Programming language foundations / Aaron Stump, Department of Computer Science, University of Iowa.
No full textcomputer bookfair2015Includes bibliographical references (pages 321-323) and index.x, 326 pages :"Stump's Programming Language Foundations is a short concise text that covers semantics, equally weighting operational and denotational semantics for several different programming paradigms: imperative, concurrent, and functional. Programming Language Foundations provides: an even coverage of denotational, operational an axiomatic semantics; extensions to concurrent and non-deterministic versions; operational semantics for untyped lambda calculus; functional programming; type systems; and coverage of emerging topics and modern research directions. "-- Provided by publisher
Simulating Large Eliminations in Cedille
No full textLarge eliminations provide an expressive mechanism for arity- and type-generic programming. However, as large eliminations are closely tied to a type theory’s primitive notion of inductive type, this expressivity is not expected within polymorphic lambda calculi in which datatypes are encoded using impredicative quantification. We report progress on simulating large eliminations for datatype encodings in one such type theory, the calculus of dependent lambda eliminations (CDLE). Specifically, we show that the expected computation rules for large eliminations, expressed using a derived type of extensional equality of types, can be proven within CDLE. We present several case studies, demonstrating the adequacy of this simulation for a variety of generic programming tasks, and a generic formulation of the simulation allowing its use for a broad family of datatype encodings. All results have been mechanically checked by Cedille, an implementation of CDLE
Type Preservation as a Confluence Problem
No full textThis paper begins with recent work by Kuan, MacQueen, and Findler,
which shows how standard type systems, such as the simply typed lambda
calculus, can be viewed as abstract reduction systems operating on
terms. The central idea is to think of the process of typing a term
as the computation of an abstract value for that term. The standard
metatheoretic property of type preservation can then be seen as a
confluence problem involving the concrete and abstract operational
semantics, viewed as abstract reduction systems (ARSs).
In this paper, we build on the work of Kuan et al. by showing show how
modern ARS theory, in particular the theory of decreasing diagrams,
can be used to establish type preservation via confluence. We
illustrate this idea through several examples of solving such problems
using decreasing diagrams. We also consider how automated tools for
analysis of term-rewriting systems can be applied in testing typ
Twenty-foot High Petrified Tree Stump, Yellowstone National Park, A
No full textTwenty-foot High Petrified Tree Stump, Yellowstone National Park,
Stump appendicitis; a case report
No full textWhen a patient has had an appendectomy, he/she may return with similar symptoms again. In this case, part of the appendix may be remain and become inflamed again, so the patient may present with symptoms similar to appendicitis, which is rare. in this report, we describe a 13 years old boy with similar symptoms to appendicitis with a history of appendectomy about 6 months ago. the patient had abdominal pain, nausea, and vomiting with fever, anorexia and diarrhea from two days ago. The patient had a gradual onset of pain with maximum severity in the RLQ region. According to clinical signs and paraclinical results, laparotomy was performed, inflammation of the remained appendix (stump appendicitis) was observed. In this group of patients, pain in the RLQ area causes differential diagnoses but due to the history of previous appendectomy, re-inflammation of the appendix called �stump appendicitis� is less noticeable and may increase mortality and morbidity. © 2020 The Author
Computing in the field: language modeling for elicitation and documentation of Shughni
No full textWe propose a way of enhancing computer-based approaches to language documentation by making use not only of the engineering capability of computing but also its modeling capacity. Our proposal arises from a documentation pilot project where we used computational modeling as an elicitation tool for documenting the complex verbal morphology of the underdocumented East Iranian Pamir language Shughni. Using the computable lexical knowledge representation language DATR (Evans & Gazdar 1996) and its variant KATR (Author et al. 2002), we wrote a theory of a fragment of the Shughni verb system based on what little we knew about the language. We then presented its theorem to our group of Shughni consultants, and based on their responses refined the model, and then consulted them on the new theorem, and so on to the next refinement. Cycling through these steps allowed us to refine our model and so lead to a more accurate account of the data. Equally importantly, this method gave us an automated ‘questionnaire generator’, i.e. the model's theorem. This provided not only elicitation queries that, given enough time, we may have thought of ourselves but those which may never have occurred to us. Both types of query were available to us precisely because our understanding of the grammar was formal and computationally implemented, and could thereby automatically generate theorems. Computing plays a key language engineering role in language documentation and its accessibility to the wider audience, from standard mark-up of data to its storage in a relational database for query-based retrieval. But computing serves a second purpose for linguists, that of language modeling: this is “the instrumental use of computation in the pursuit of linguistic goals” (Thompson 1983: 23). As we develop new methods for documentation, we need to explore the possibility of harnessing this other language modeling capacity of computing. We demonstrate through our work on Shughni that computer modeling can be a means of furnishing the field-worker with elicitation tasks whose results feed into an enhanced understanding of the data, which in turn show the path to the next stage of elicitation, ultimately leading to a well-informed and robust account of the data which is already digitized and therefore exchangeable. Advances in technology, such as palm-held computers, mean that an automated model-theorem-refinement method is both a practical and potentially highly valuable addition to the field-worker’s toolkit, both while in the field and back in the lab
Primary data of the mechanized stump extraction in Estonia
No full textTöö annab ülevaate tööaja jaotumisest, ekskavaatori tootlikkusest ja juurimisoperatsioonideks kuluva aja seosest kännu diameetriga. Varasemalt pole Eestis sarnaseid uurimusi läbi viidud, kuid samalaadsest valdkonnast võib leida palju välismaiseid artikleid.
Antud töö eesmärgiks oli teada saada, erinevatel katsealadel, juurimismasina tootlikkus ja diameetri mõju kändude juurimise ajale. Töö on valminud autori poolt kronometreeritud andmete põhjal. Andmete töötlemiseks kasutas autor L. G. Marklundi maa-alust biomassivalemit ja P. Hakkila kändude keskmist tihedust.
Tööst selgus, et kändude diameeter mõjutab oluliselt juurimisoperatsioonideks kuluvat aega. Diameetri suurenedes, suureneb aeg kännu juurimisoperatsioonideks. Suurema diameetriga kändudest saab jällegi rohkem biomassi, mistõttu tootlikkus ühes efektiivses töötunnis on suurem. Näiteks Orguse kännu alalt, kust juuriti 49 kändu efektiivses töötunnis ja kännu keskmine diameeter oli 46,1 cm, saadi tootlikkuseks 16,8 m3/Eh, kuid Rõuge kännu alalt, kust juuriti 52 kändu ja keskmine diameeter oli 43,3 cm, saadi tootlikkuseks 16,2 m3 efektiivses töötunnis.
Töös saadud eksponentvõrrandeid ja parameetreid kasutades saab prognoosida, kui palju aega kulub kännu juurimiseks, teades kännu diameetrit. Uurimustöö materjali, saab kasutada edasiseks arendamiseks magistritööks.The research gives an overview of the time distribution, the productivity of the excavator and the relationship between stump extraction time and stump diameter. Previously, in Estonia, similar studies have not been performed, but in a similar field may find a lot of foreign articles.
Purpose of this research was to find out excavator productivity and the influence of the stump diameter to extraction time in the different plots. The research is done by the author chronometration data. Processing of the data, L. G. Marklund below-ground biomass formula and P. Hakkila average stump density were used.
Research showed that the diameter of the stump have a significant impact to stump extraction time. Increasing diameter increases the extraction time of the stump. From larger stumps the amount of biomass is higher, which increases the productivity in the one effective working hour. For example, Orguse stump area, where extracted 49 stumps in effective working hour and the average stump diameter was 46,1 cm, the results was 16,8 m3/Eh, but Rõuge stump area, where extracted 52 stumps and the average diameter of the stump was 43,3 cm, the productivity was 16,2 m3 of the effective working hour.
Exponential equation and parameters from research can be used to predict how much time stump extraction will take, knowing the diameter of the stump. Research material can be used for further development of the master's thesis
Thrombosis in the Pulmonary Vein Stump After Left Upper Lobectomy as a Possible Cause of Cerebral Infarction
No full textBackground. Thrombus in the stump of the pulmonary vein (PV) is not a well-known complication after lung resection, and it has the potential to cause embolism to vital organs. To clarify the frequency, risk factors, and cause of this complication, a retrospective clinical study of patients who underwent lobectomy was performed. Methods. The study evaluated 193 patients with primary lung cancer who underwent lobectomy from 2005 to 2011 and contrast-enhanced chest computed tomography (CT) within 2 years after lobectomy. Contrast-enhanced CT was retrospectively interpreted to check for thrombus in the PV stump. Results. The operative procedures were 65 right upper lobectomies, 14 right middle lobectomies, 40 right lower lobectomies, 52 left upper lobectomies (LUL), and 22 left lower lobectomies. Thrombus developed in the PV stump in 7 of the 193 patients (3.6%) after lobectomy. All patients with thrombus had undergone LUL, and 13.5% of those who had undergone LUL developed thrombus. Univariate analyses revealed that LUL and operation time were significant risk factors and that adjuvant chemotherapy was marginally significant. It appears that thrombus may be attributable to the length of the PV stump. Measurement of the length of the PV stump using 3-dimensional CT images of the PV revealed that the stump of the left superior PV was longer than the others. Conclusions. Thrombus in the PV stump occurred in 13.5% of patients after LUL. These findings suggest that contrast-enhanced CT should be recommended for patients after LUL to help identify those with a high risk for thromboembolism. (C) 2013 by The Society of Thoracic Surgeon
Proof Checking Technology for Satisfiability Modulo Theories
No full textAbstractA common proof format for solvers for Satisfiability Modulo Theories (SMT) is proposed, based on the Edinburgh Logical Framework (LF). Two problems arise: checking very large proofs, and keeping proofs compact in the presence of complex side conditions on rules. Incremental checking combines parsing and proof checking in a single step, to avoid building in-memory representations of proof subterms. LF with Side Conditions (LFSC) extends LF to allow side conditions to be expressed using a simple first-order functional programming language. Experimental data with an implementation show very good proof checking times and memory usage on benchmarks including the important example of resolution inferences
Stabilization of the Proximal Ulnar Stump in the Sauvé-Kapandji Procedure by Using the Extensor Carpi Ulnaris Tendon: Long-Term Follow-Up Studies
No full textPurpose: The Sauvé-Kapandji (S-K) procedure is considered a useful treatment option for distal radioulnar disorders. However, postoperative instability of the proximal ulnar stump and radioulnar convergence may be symptomatic. We modified the Sauvé-Kapandji procedure by stabilizing the proximal ulnar stump with a half-slip of the extensor carpi ulnaris tendon. We previously reported 13 patients with this procedure at an average follow-up of 35 months; the patients had satisfactory clinical results and improved stability of the proximal ulnar stump as shown by x-ray examination. In this paper, we address the question of whether those clinical and radiographic results noted at an average follow-up of 35 months postoperativery are maintained at later follow-up examinations.
Methods: We reexamined 12 of the 13 original patients and compared their intial follow-up results with their current results after an average follow-up of 95 months. Results: The results of this series after 95 months were similar to those at 35-months. These overall results suggest that the clinical and radiographic results at 35-month follow-up were maintained at the final follow-up visit.
Conclusions: Our results in this paper suggested that the clinical radiographic results at the 35-month follow-up were maintained in the long-term 95-month follow-up despite the finding that the hole in the proximal ulnar stump had broken in three wrists at follow-up
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