Model learning and test generation using cover automata

We propose an approach which, given a state-transition model of a system, constructs, in parallel, an approximate automaton model and a test suite for the system. The approximate model construction relies on a variant of Angluin's automata learning algorithm, adapted to finite cover automata. A finite cover automaton represents an approximation of the system which only considers sequences of length up to an established upper bound . Crucially, the size of the cover automaton, which normally depends on , can be significantly lower than the size of the exact automaton model. Thus, controlling , the state explosion problem normally associated with constructing and checking state based models can be mitigated. The proposed approach also allows for a gradual construction of the model and of the associated test suite, with complexity and time savings. Moreover, we provide automation of counterexample search, by a combination of black-box and random testing, and metrics to evaluate the quality of the produced results. The approach is presented and implemented in the context of the Event-B modeling language, but its underlying ideas and principles are much more general and can be applied to any system whose behavior can be suitably described by a state-transition model

Estudio y evaluación de la identidad digital en Blockchain

Este proyecto consiste en un estudio teórico de la identidad descentralizada basada en Blockchain (identidad soberana), así como las soluciones existentes para la gestión de la identidad en Blockchain. Dichas soluciones son: Alastria ID, Sovrin, Hyperledger Indy y uPort. Finalmente, también se presenta una pequeña tabla comparativa de las principales características de cada una de las soluciones que se han analizado. La segunda parte de este proyecto (parte práctica) consiste en diseñar y poner en marcha una solución de identidad soberana partiendo de la base de alguna de las soluciones examinadas en el apartado teórico (Hyperledger Indy). Posteriormente se realizará una adaptación del sistema que se ha puesto en marcha para el ámbito de la salud, concretamente para el traspaso de expedientes médicos entre diferentes instituciones sanitarias de diferentes comunidades autónomas o países, teniendo en cuenta el actual Reglamento de Protección de Datos (GDPR) de la Unión Europea (UE). Finalmente, para cumplir el objetivo principal del proyecto, se hará una evaluación del sistema de intercambio de expedientes puesto en marcha con Hyperledger Indy.This project consists of a theoretical study of decentralized identity (blockchain - sovereign identity), as well as the existing solutions for decentralized identity management. These solutions are: Alastria ID, Sovrin, Hyperledger Indy and uPort. Finally, a comparative table of the main characteristics of each of the solutions that have been analyzed is also presented. The second part of this project consists of designing and implementing a sovereign identity solution based on one of the solutions examined in the theoretical section (Hyperledger Indy). Subsequently, an adaptation of the system that has been implemented for the healthcare field will be carried out, specifically for the transfer of medical records between different healthcare institutions in different regions or countries, taking into account the current Data Protection Regulation (GDPR) of the European Union (EU). Finally, in order to fulfil the main objective of the project, an evaluation of the exchange system implemented with Hyperledger Indy will also be carried out.Aquest projecte consisteix en un estudi teòric de la identitat descentralitzada basada en Blockchain (identitat sobirana), així com les solucions existents per a la gestió de la identitat en Blockchain. Aquestes solucions són: Alastria ANEU, Sovrin, Hyperledger Indy i uPort. Finalment, també es presenta una petita taula comparativa de les principals característiques de cadascuna de les solucions que s'han analitzat. La segona part d'aquest projecte (part pràctica) consisteix a dissenyar i posar en marxa una solució d'identitat sobirana partint de la base d'alguna de les solucions examinades en l'apartat teòric (Hyperledger Indy). Posteriorment es realitzarà una adaptació del sistema que s'ha posat en marxa per a l'àmbit de la salut, concretament per al traspàs d'expedients mèdics entre diferents institucions sanitàries de diferents comunitats autònomes o països, tenint en compte l'actual Reglament de Protecció de Dades (GDPR) de la Unió Europea (UE). Finalment, per a complir l'objectiu principal del projecte, es farà una avaluació del sistema d'intercanvi d'expedients posat en marxa amb Hyperledger Indy

Implementing Realistic Asynchronous Automata

Zielonka’s theorem, established 25 years ago, states that any regular language closed under commutation is the language of an asynchronous automaton (a tuple of automata, one per process, exchanging information when performing common actions). Since then, constructing asynchronous automata has been simplified and improved [6, 19, 7, 12, 8, 4, 2, 20, 21]. We first survey these constructions and conclude that the synthesized systems are not realistic in the following sense: existing constructions are either plagued by deadends, non deterministic guesses, or the acceptance condition or choice of actions are not distributed. We tackle this problem by giving (effectively testable) necessary and sufficient conditions which ensure that deadends can be avoided, acceptance condition and choices of action can be distributed, and determinism can be maintained. Finally, we implement our constructions, giving promising results when compared with the few other existing prototypes synthesizing asynchronous automata

Applying the Direct Absorption Method and LSC for 14C Concentration Measurement in Aqueous Samples

From the 19th International Radiocarbon Conference held in Keble College, Oxford, England, April 3-7, 2006.We investigated a simple, reliable radiocarbon measurement procedure for water samples using the direct absorption method for sample preparation, followed by low-level liquid scintillation spectrometry. This process has involved quantitative evaluation of the conversion steps in order to estimate the appropriate working parameters. The 14C activity of dissolved inorganic carbon (DIC) for several types of water (ranging from seawater to groundwater) has been measured, paying attention to the preparation requirements of each type of water. The main advantage of this method is the simplified sample preparation, allowing measurement of a great number of samples in less time. This method was designed for routine analysis of water samples, and it is proposed particularly for use in 14C monitoring programs of CANDU-type reactors.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

Radiocarbon and Tritium Levels along the Romanian Lower Danube River

From the 20th International Radiocarbon Conference held in Kona, Hawaii, USA, May 31-June 3, 2009.The Lower Danube Basin covers the Romanian-Bulgarian sub-basin downstream from Cazane Gorge and the sub-basins of the Siret and Prut rivers. To extensively survey the Romanian nuclear power plant impact on the Danube water, tritium and radiocarbon baseline values are required. Therefore, the reported study tried to establish these values based on a 2-yr sampling campaign covering 975 km of the Danube from Cazane Gorge to Tulcea. The tributaries Cerna, Jiu, Olt, and Arges were also included in this study. During the sampling campaigns, tritium concentration of different sampling locations showed values between 7 ± 2.1 and 33.5 ± 2.3 TU. Measured 14C activity for the same locations ranged between 88.45 ± 1.46 and 112.36 ± 1.56 pMC. Lower values were recorded for tributaries: between 8.3 ± 2.1 and 12.2 ± 2.2 TU for tritium and between 67.3 ± 1.29 and 86.04 ± 1.42 pMC for 14C. Despite the nuclear activity in the observed areas, tritium and 14C activities presented slightly higher values for specific locations without any influence on Danube River water.The Radiocarbon archives are made available by Radiocarbon and the University of Arizona Libraries. Contact [email protected] for further information.Migrated from OJS platform February 202

A new Time-of-flight detector for the R 3 B setup

© 2022, The Author(s).We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R3B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision σΔE/ ΔE of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.11Nsciescopu

Stoma-free survival after anastomotic leak following rectal cancer resection: worldwide cohort of 2470 patients

Background: The optimal treatment of anastomotic leak after rectal cancer resection is unclear. This worldwide cohort study aimed to provide an overview of four treatment strategies applied. Methods: Patients from 216 centres and 45 countries with anastomotic leak after rectal cancer resection between 2014 and 2018 were included. Treatment was categorized as salvage surgery, faecal diversion with passive or active (vacuum) drainage, and no primary/secondary faecal diversion. The primary outcome was 1-year stoma-free survival. In addition, passive and active drainage were compared using propensity score matching (2: 1). Results: Of 2470 evaluable patients, 388 (16.0 per cent) underwent salvage surgery, 1524 (62.0 per cent) passive drainage, 278 (11.0 per cent) active drainage, and 280 (11.0 per cent) had no faecal diversion. One-year stoma-free survival rates were 13.7, 48.3, 48.2, and 65.4 per cent respectively. Propensity score matching resulted in 556 patients with passive and 278 with active drainage. There was no statistically significant difference between these groups in 1-year stoma-free survival (OR 0.95, 95 per cent c.i. 0.66 to 1.33), with a risk difference of -1.1 (95 per cent c.i. -9.0 to 7.0) per cent. After active drainage, more patients required secondary salvage surgery (OR 2.32, 1.49 to 3.59), prolonged hospital admission (an additional 6 (95 per cent c.i. 2 to 10) days), and ICU admission (OR 1.41, 1.02 to 1.94). Mean duration of leak healing did not differ significantly (an additional 12 (-28 to 52) days). Conclusion: Primary salvage surgery or omission of faecal diversion likely correspond to the most severe and least severe leaks respectively. In patients with diverted leaks, stoma-free survival did not differ statistically between passive and active drainage, although the increased risk of secondary salvage surgery and ICU admission suggests residual confounding