Diversifying focused testing for unit testing

Software changes constantly because developers add new features or modifications. This directly affects the effectiveness of the testsuite associated with that software, especially when these new modifications are in a specific area that no test case covers. This paper tackles the problem of generating a high quality test suite to cover repeatedly a given point in a program, with the ultimate goal of exposing faults possibly affecting the given program point. Both search based software testing and constraint solving offer ready, but low quality, solutions to this: ideally a maximally diverse covering test set is required whereas search and constraint solving tend to generate test sets with biased distributions. Our approach, Diversified Focused Testing (DFT), uses a search strategy inspired by GödelTest. We artificially inject parameters into the code branching conditions and use a bi-objective search algorithm to find diverse inputs by perturbing the injected parameters, while keeping the path conditions still satisfiable. Our results demonstrate that our technique, DFT, is able to cover a desired point in the code at least 90% of the time. Moreover, adding diversity improves the bug detection and the mutation killing abilities of the test suites. We show that DFT achieves better results than focused testing, symbolic execution and random testing by achieving from 3% to 70% improvement in mutation score and up to 100% improvement in fault detection across 105 software subjects

UWE en Sistema de Recomendación de Objetos de Aprendizaje. Aplicando Ingeniería Web: Un Método en Caso de Estudio

La Ingeniería Web propone nuevos métodos para el diseño de aplicaciones que se ejecutan en esta nueva plataforma que es la World Wide Web. Uno de estos métodos es UWE (UML Web Engineering), el cual aprovecha la notación estándar del UML e incorpora elementos que son propios del desarrollo Web. En este artículo se presenta un caso de estudio para el diseño de un Sistema de Recomendación de Objetos de Aprendizaje, donde el modelado básico se realiza mediante el UWE. Se modela una aplicación Web que permite a los usuarios realizar la composición de los Objetos de Aprendizaje que el mismo sistema le recomienda al usuario previo análisis de las características tanto del mismo como de los Objeto de Aprendizaje almacenados en un repositorio especializado llamado AGORA

Electronic structure of crystalline binary and ternary Cd-Te-O compounds

The electronic structure of crystalline CdTe, CdO, $\alpha$-TeO$_2$, CdTeO$_3$ and Cd$_3$TeO$_6$ is studied by means of first principles calculations. The band structure, total and partial density of states, and charge densities are presented. For $\alpha$-TeO$_2$ and CdTeO$_3$, Density Functional Theory within the Local Density Approximation (LDA) correctly describes the insulating character of these compounds. In the first four compounds, LDA underestimates the optical bandgap by roughly 1 eV. Based on this trend, we predict an optical bandgap of 1.7 eV for Cd$_3$TeO$_6$. This material shows an isolated conduction band with a low effective mass, thus explaining its semiconducting character observed recently. In all these oxides, the top valence bands are formed mainly from the O 2p electrons. On the other hand, the binding energy of the Cd 4d band, relative to the valence band maximum, in the ternary compounds is smaller than in CdTe and CdO.Comment: 13 pages, 15 figures, 2 tables. Accepted in Phys Rev

Modeling the acquisition front-end in high resolution gamma-ray imaging

The availability of synthetic realistic data eases design optimization, algorithm evaluation and verification of any digital system where a significant amount of digital signal processing is performed. The evolution of positron emission tomography cameras towards continuous sampling of individual position-sensitive photomultiplier anodes with processing algorithms implemented on digital programmable logic devices creates a new framework where new approaches to the γ-event detection are possible. We have developed a system model of the acquisition chain, including multi-layer phoswich, photomultiplier, front-end analog electronics, data acquisition and digital processing. This processing includes estimation algorithms for the most relevant event parameters: energy, layer-of-interaction, time picking-off and event location. The selected simulation platform couples gently to digital hardware simulation tools, in such a way that implemented models may generate real-like stimuli for the digital system under development. The modeling of the whole front-end electronics enables deeper understanding and tuning of different system trade-offs and provides a rapid and soft transition between specification and hardware developmentPublicad

Effects of MDMA on blood glucose levels and brain glucose metabolism

Purpose This study was designed to assess changes in glucose metabolism in rats administered single or repeated doses of MDMA. Methods Two different experiments were performed: (1) A single-dose study with four groups receiving 20 mg/kg, 40 mg/kg, saline or heat, and (2) a repeated-dose study with two groups receiving three doses, at intervals of 2 h, of 5 mg/kg or saline. Rats were imaged using a dedicated small-animal PET scanner 1 h after single-dose administration or 7 days after repeated doses. Glucose metabolism was measured in 12 cerebral regions of interest. Rectal temperature and blood glucose were monitored. Results Peak body temperature was reached 1 h after MDMA administration. Blood glucose levels decreased significantly after MDMA administration. In the single-dose experiment, brain glucose metabolism showed hyperactivation in cerebellum and hypo-activation in the hippocampus, amygdala and auditory cortex. In the repeated-dose experiment, brain glucose metabolism did not show any significant change at day 7. Conclusion These results are the first to indicate that MDMA has the potential to produce significant hypoglycaemia. In addition, they show that MDMA alters glucose metabolism in components of the motor, limbic and somatosensory systems acutely but not on a long-term basisPublicad

New embedded digital front-end for high resolution PET scanner

This work describes a new digital front-end for a high-resolution low-cost animal PET scanner which is currently under development. The advances in flexibility and size of modern FPGAs together with the release of new tools enable the integration of most of the front-end electronics in a single FPGA. The implemented system includes a small 32-bit RISC processor, several peripherals attached to the internal buses and a special DSP unit closely attached to the processor which is dedicated to the detection of the gamma events. On top of these, a small footprint real time operating system abstracts the underlying hardware, providing the mechanisms to combine on-chip slow control and data streamingThis work was supported in part by the FPU Research Grant from the Spanish Education and Science Ministry, by the Spanish Thematic Network IM3 (PI052204) and project TEC2004-07052-C02-02Publicad

Development and Initial testing of a Virtual Laboratory for the Build-up and Testing of Microgrid Management Algorithms

In a bid of facilitating the increasing penetration of intermittent and random renewable energies, microgrids along with their management algorithms are becoming crucial assets. To prove their effectiveness, these algorithms need to be tested in real environments and/or laboratories, which can be very difficult in many cases, especially at the initial development stages. To solve this issue, this article proposes the use of a laboratory digital twin, i.e., a virtual laboratory with a behaviour that is similar to that of real installations, aimed at facilitating the development, testing and debugging of microgrids management algorithms. The proposed solution is demonstrated to be safe and complete when it comes to test these algorithms.Acknowledgement This publication is part of the Sistemas energéticos aislados 100% renovables ENERISLA (exp. CER-20191002) Project which has received a grant from the Centre for Industrial Technological Development (CDTI, Centro para el Desarrollo Tecnológico Industrial in Spanish) under the Ministry of Science and Innovation in the call Acreditación y Concesión de Ayudas destinadas a Centros Tecnológicos de Excelencia “Cervera” in 2019. This research has received funding from the European Union’s Horizon 2020 Framework Program for Research and Innovation under grant agreement no. 893857

Real-Time Digital Timing in Positron Emission Tomography

Positron emission tomography (PET) requires accurate timing of scintillation events to properly discriminate between coincident and noncoincident pairs. The traditional solution to timing is based on custom application specific integrated circuits (ASIC) designs, whose cost may not be justified in the design of experimental small animal PET scanners. The new generation of PET scanners introduces the idea of continuous sampling of the detected scintillation pulse, replacing event-triggered acquisition front-ends. This approach enables new options to the timing procedure based on digital processing of the sampled pulse signal. This work proposes a time stamping algorithm based on the optically matched filter and compares the potential performance benefits of this approach versus other FIR-based timing algorithms, some of which have been already implemented by different authors. Results show that the coincidence timing resolution may be as low as 1.5 ns without the need of expensive high-speed converters when the proper signal processing is appliedIEEE Nuclear and Plasma Sciences SocietyPublicad

Quantification of SPIO using T2* and phase imaging

Proceeding of: 17th Scientific Meeting, International Society for Magnetic Resonance in Medicine, 18-24 April, 2009, Honolulu, Hawai, USAPublicad