Diabetic retinopathy affects millions of working-age people worldwide. Of the countries in Latin America, Brazil has the highest incidence of cases. Diabetic retinopathy is detected through images of the fundus that contain lesions such as hard exudates, soft exudates, microaneurysms, and hemorrhages. Early identification of these lesions prevents the progression of the disease, which leads to a decrease in visual capacity. In addition, the early identification of these lesions allows the screening of patients who need priority care. The detection of these lesions occurs through the processing and analysis of fundus images using deep learning models. In this work, we present a new method that uses the You Only Learn One Representation with Cross Stage Partial Network (YOLOR-CSP) architecture combined with the Slicing Aided Hyper Inference (SAHI) framework to detect lesions. The proposed method was trained, adjusted, and evaluated using the Dataset for Diabetic Retinopathy (DDR) and the Indian Diabetic Retinopathy Image Dataset (IDRiD). The proposed method obtained in the data set DDR mAP equal to 38.08%, in the validation set, and 22.25% in the test set with SGD optimizer. The presented results were superior in the detection of eye fundus lesions in comparison with similar works found in the state-of-the-art literature.

This article proposes an integrated approach for reliability modeling and maintenance scheduling of repairable parallel systems subject to hidden failures. The system consists of heterogeneous redundant subsystems whose failures are detected only by inspections. Inspections at periodic times reveal the components state, and repair actions are decided by the excursion of a basic state process describing the total number of failed components (deterioration level) in each subsystem. Using the standard renewal arguments, this article aims at minimizing the average cost rate by the joint determination of the optimal inspection interval$\tau$and maintenance parameters$\kappa$(partial repair threshold) and$\ell$(preventive replacement threshold). We illustrate the procedure for the case as the components’ lifetimes conform to the Weibull distribution. The proposed model and the response of the optimal solutions to the model’s parameters are illustrated through numerical examples. The approach outlined here allows exploring different scenarios and further extensions.

Model Driven Engineering (MDE) techniques raise the level of abstraction at which developers construct software. However, modern cyber-physical systems are becoming more prevalent and complex and hence software models that represent the structure and behavior of such systems still tend to be large and complex. These models may have numerous if not infinite possible behaviors, with complex communications between their components. Appropriate software testing techniques to generate test cases with high coverage rate to put these systems to test at the model-level (without the need to understand the underlying code generator or refer to the generated code) are therefore important. Concolic testing, a hybrid testing technique that benefits from both concrete and symbolic execution, gains a high execution coverage and is used extensively in the industry for program testing but not for software models. In this paper, we present a novel technique and its tool mCUTE1, an open source 2 model-level concolic testing engine. We describe the implementation of our tool in the context of Papyrus-RT, an open source Model Driven Engineering (MDE) tool based on UML-RT, and report the results of validating our tool using a set of benchmark models.

Testing models of modern cyber-physical systems is not straightforward due to timing constraints, numerous if not infinite possible behaviors, and complex communications between components. Software testing tools and approaches that can generate test cases to test these systems are therefore important. Many of the existing automatic approaches support testing at the implementation level only. The existing model-level testing tools either treat the model as a black box (e.g., random testing approaches) or have limitations when it comes to generating complex test sequences (e.g., symbolic execution). This paper presents a novel approach and tool support for automatic unit testing of models of real-time embedded systems by conducting concolic testing, a hybrid testing technique based on concrete and symbolic execution. Our technique conducts automatic concolic testing in two phases. In the first phase, model is isolated from its environment, is transformed to a testable model and is integrated with a test harness. In the second phase, the harness tests the model concolically and reports the test execution results. We describe an implementation of our approach in the context of Papyrus-RT, an open source Model Driven Engineering (MDE) tool based on the modeling language UML-RT, and report the results of applying our concolic testing approach to a set of standard benchmark models to validate our approach.

Models of Real-time Embedded (RTE) systems may encompass many components with often many different kinds of dependencies describing, e.g., structural relationships or the flow of data, control, or messages. Understanding and properly accounting for them during development, testing and debugging can be challenging. This paper presents an approach for slicing models of RTE systems to facilitate model understanding and other model-level activities. A key novelty of our approach is the support for models with composite components (with multiple hierarchical levels) and capturing the dependencies that involve structural and behavioural model elements, including a combination of the two. Moreover, we describe an implementation of our approach in the context of Papyrus-RT, an open source Model Driven Engineering (MDE) tool based on the modeling language UML-RT. We conclude the paper with the results of applying our slicer to a set of UML-RT models to validate our approach and to demonstrate the applications of our approach for facilitating model-level analysis tasks, such as testing and debugging.

This paper describes the design of traits, abstract superclasses, in the verification-aware programming language Dafny. Although there is no inheritance among classes in Dafny, the traits make it possible to describe behavior common to several classes and to write code that abstracts over the particular classes involved. The design incorporates behavioral specifications for a trait's methods and functions, just like for classes in Dafny. The design has been implemented in the Dafny tool.

This work compares the dynamic performance of a PV charger system designed using three different power electronic converters. First it introduces the PV charger system and the three converters. Next, it presents the dynamic model of the three converters. Then, it uses the dynamic models to study and compare the dynamic performance of the converters in a range of operating points. Finally, it offers time domain simulation results to verify the theoretical outcomes.

This paper provides an easy yet accurate approach for estimating vehicle inertia for the purpose of simulating the effect of vehicle inertia using a large flywheel. The method used to properly map the linear inertia of a vehicle to an equivalent rotational inertia is described in detail and an expression for equivalent rotational inertia of a vehicle is derived analytically using two different approaches considering kinetic energy of a moving mass in the linear and rotational context and vehicle dynamic equations. A MATLAB/Simulink model of a test bench consisting of a torque actuator connected to a large flywheel is used to emulate the effect of vehicle inertia. Using this model, the dynamic inertia effect of an electric vehicle on its traction motor is illustrated for two standard drive cycles. The results obtained from simulation are validated by ADVISOR to confirm the effectiveness of the proposed method in estimating vehicle inertia and it is shown that the use of a flywheel with a calculated rotational inertia using the proposed method can be sufficient in emulating vehicle inertia effect on a test bench.