Concurrent Model Transformations with Linda

Nowadays, model transformations languages and engines use a sequential execution model. This is, only one execution thread deals with the whole transformation. However, model transformations dealing with very large models, such as those used in biology or aerospace applications, require concurrent solutions in order to speed up their performance. In this ongoing work we explore the use of Linda for implementing a set of basic mechanisms to enable concurrent model transformations, and present our initial results.Proyectos TIN2011-23795, TIN2011-15497-E y Andalucía Tech Campus de Excelencia

On the Modular Specification of NFPs: A Case Study

The modular specification of non-functional properties of systems is a current challenge of Software Engineering, for which no clear solution exists. However, in the case of Domain-Specific Languages some successful proposals are starting to emerge, combining model-driven techniques with aspect-weaving mechanisms. In this paper we show one of these approaches in practice, and present the implementation we have developed to fully support it. We apply our approach for the specification and monitoring of non-functional properties using observers to a case study, illustrating how generic observers defining non-functional properties can be defined in an independent manner. Then, correspondences between these observers and the domain-specific model of the system can be established, and then weaved into a unified system specification using ATL model transformation. Such a unified specification can also be analyzed in a natural way to obtain the required non-functional properties of the system.This work is partially funded by Research Projects TIN2011-23795 and TIN2011-15497-E

Improving query performance on dynamic graphs

Querying large models efficiently often imposes high demands on system resources such as memory, processing time, disk access or network latency. The situation becomes more complicated when data are highly interconnected, e.g. in the form of graph structures, and when data sources are heterogeneous, partly coming from dynamic systems and partly stored in databases. These situations are now common in many existing social networking applications and geo-location systems, which require specialized and efficient query algorithms in order to make informed decisions on time. In this paper, we propose an algorithm to improve the memory consumption and time performance of this type of queries by reducing the amount of elements to be processed, focusing only on the information that is relevant to the query but without compromising the accuracy of its results. To this end, the reduced subset of data is selected depending on the type of query and its constituent f ilters. Three case studies are used to evaluate the performance of our proposal, obtaining significant speedups in all cases.This work is partially supported by the European Commission (FEDER) and the Spanish Government under projects APOLO (US-1264651), HORATIO (RTI2018-101204-B-C21), EKIPMENT-PLUS (P18-FR-2895) and COSCA (PGC2018-094905B-I00)

Towards Approximate Model Transformations

As the size and complexity of models grow, there is a need to count on novel mechanisms and tools for transforming them. This is required, e.g., when model transformations need to provide target models without having access to the complete source models or in really short time—as it happens, e.g., with streaming models—or with very large models for which the transformation algorithms become too slow to be of practical use if the complete population of a model is investigated. In this paper we introduce Approximate Model Transformations, which aim at producing target models that are accurate enough to provide meaningful and useful results in an efficient way, but without having to be fully correct. So to speak, this kind of transformations treats accuracy for execution performance. In particular, we redefine the traditional OCL operators used to query models (e.g., allInstances, select, collect, etc.) by adopting sampling techniques and analyse the accuracy of approximate model transformations results.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. European Commission under the ICT Policy Support Programme (grant no. 317859). Research Project TIN2011-23795

Uncertainty representation in software models: a survey

This paper provides a comprehensive overview and analysis of research work on how uncertainty is currently represented in software models. The survey presents the definitions and current research status of different proposals for addressing uncertainty modeling and introduces a classification framework that allows to compare and classify existing proposals, analyze their current status and identify new trends. In addition, we discuss possible future research directions, opportunities and challenges.This work is partially supported by the European Commission (FEDER) and the Spanish Government under projects APOLO (US1264651), HORATIO (RTI2018-101204-B-C21), EKIPMENT-PLUS (P18-FR-2895) and COSCA (PGC2018-094905-B-I00)

On the Realization of TractsTool

Model transformations play an important role in Model-Driven Engineering (MDE), and as their size and complexity grow, there is an increasing need to count on tool support for testing their correctness. In this presentation, we introduce TractsTool, a tool for specifying and testing several different kinds of model transformations, e.g., model-to-model, model-to-text, and text-to-model transformations, based on contracts. We explain the main principles behind the tool, demonstrate some of its capabilities by a running example, and show how it is internally realized by using MDE techniques. In particular, we describe the transformation chain that is used to compute the test results. TractsTool with accompanying information is available at: http://atenea.lcc.uma.es/index.php/Main_Page/Resources/Tract

Key-Value vs Graph-based data lakes for realizing Digital Twin systems

Digital twins constitute virtual representations of physically existing systems, synchronized at a specified frequency and fidelity. One way to connect physical and digital twins is through data lakes, which are efficient storage and query processing systems to manage the data exchanged between the twins. Existing digital twin systems make use of NoSQL or time databases for realizing their data lakes. Although very efficient, these proposals present some limitations for implementing non-trivial queries over highly connected data. In this paper we explore the use of graph databases for implementing data lakes, compare them with similar NoSQL proposals, and discuss the situations where one solution outperforms the other.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Análisis de Conformidad de Gemelos Digitales Multi-Fidelidad

Un gemelo digital es una réplica virtual de un sistema a un cierto nivel de fidelidad, sincronizados a una determinada frecuencia. Los gemelos digitales suelen emplearse para replicar sistemas físicos cuyas simulaciones son computacionalmente muy costosas. Una de las soluciones que la literatura propone a este problema es definir una jerarquía de gemelos digitales multi-fidelidad, donde dependiendo del propósito concreto, empleemos un gemelo u otro. Sin embargo, uno de los problemas que surgen es la necesidad de determinar si los distintos gemelos son equivalentes entre ellos y conforme al sistema físico. En este artículo exploramos distintos métodos para medir esta equivalencia analizando el estado y el comportamiento de los gemelos.II Plan Propio de Investigación, Transferencia y Divulgación Científica de la UMA // Proyecto COSCA (PGC2018-094905-B-I00) del Ministerio de Ciencia e Innovación - Agencia Estatal de Investigació

Evaluation of dried blood spot samples for screening of hepatitis C and human immunodeficiency virus in a real-world setting

Both hepatitis C virus (HCV) infection and human immunodeficiency virus (HIV) infection are underdiagnosed, particularly in low-income countries and in difficult-to-access populations. Our aim was to develop and evaluate a methodology for the detection of HCV and HIV infection based on capillary dry blood spot (DBS) samples taken under real-world conditions. We carried out a cross-sectional study of 139 individuals (31 healthy controls, 68 HCV-monoinfected patients, and 40 HCV/HIV-coinfected patients). ELISA was used for anti-HCV and anti-HIV antibody detection; and SYBR Green RT-PCR was used for HCV-RNA detection. The HIV serological analysis revealed 100% sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). The HCV serological analysis revealed a sensitivity of 92.6%, specificity of 100%, PPV of 100%, and NPV of 79.5%. Finally, the HCV-RNA detection test revealed a detection limit of 5 copies/µl with an efficiency of 100% and sensitivity of 99.1%, specificity of 100%, PPV of 100%, and NPV of 96.9%. In conclusion, our methodology was able to detect both HCV infection and HIV infection from the same DBS sample with good diagnostic performance. Screening for HCV and HIV using DBS might be a key strategy in the implementation of national programs for the control of both infections.We acknowledge the patients’ involvement in this study. The authors thank Thomas O’Boyle for writing assistance during the preparation of the manuscript. This study was supported by grants from Fondo de Investigación de Sanidad en España (FIS) [Spanish Health Founds for Research] [grant numbers PI14CIII/00011] Red Española de Investigación en SIDA (RIS) [AIDS Research Network] [grant numbers RD16CIII/0002/0002RD16] and a research grant from Merck Sharpe & Dohme (MISP IIS#54846).S

Autoantibodies neutralizing type I IFNs are present in ~4% of uninfected individuals over 70 years old and account for ~20% of COVID-19 deaths

Publisher Copyright: © 2021 The Authors, some rights reserved.Circulating autoantibodies (auto-Abs) neutralizing high concentrations (10 ng/ml; in plasma diluted 1:10) of IFN-alpha and/or IFN-omega are found in about 10% of patients with critical COVID-19 (coronavirus disease 2019) pneumonia but not in individuals with asymptomatic infections. We detect auto-Abs neutralizing 100-fold lower, more physiological, concentrations of IFN-alpha and/or IFN-omega (100 pg/ml; in 1:10 dilutions of plasma) in 13.6% of 3595 patients with critical COVID-19, including 21% of 374 patients >80 years, and 6.5% of 522 patients with severe COVID-19. These antibodies are also detected in 18% of the 1124 deceased patients (aged 20 days to 99 years; mean: 70 years). Moreover, another 1.3% of patients with critical COVID-19 and 0.9% of the deceased patients have auto-Abs neutralizing high concentrations of IFN-beta. We also show, in a sample of 34,159 uninfected individuals from the general population, that auto-Abs neutralizing high concentrations of IFN-alpha and/or IFN-omega are present in 0.18% of individuals between 18 and 69 years, 1.1% between 70 and 79 years, and 3.4% >80 years. Moreover, the proportion of individuals carrying auto-Abs neutralizing lower concentrations is greater in a subsample of 10,778 uninfected individuals: 1% of individuals 80 years. By contrast, auto-Abs neutralizing IFN-beta do not become more frequent with age. Auto-Abs neutralizing type I IFNs predate SARS-CoV-2 infection and sharply increase in prevalence after the age of 70 years. They account for about 20% of both critical COVID-19 cases in the over 80s and total fatal COVID-19 cases.Peer reviewe