An Introduction to Software Testing

The development of large software systems is a complex and error prone process. Faults might occur at any development stage and they must be identified and removed as early as possible to stop their propagation and reduce verification costs. Quality engineers must be involved in the development process since the very early phases to identify required qualities and estimate their impact on the development process. Their tasks span over the whole development cycle and go beyond the product deployment through maintenance and post mortem analysis. Developing and enacting an effective quality process is not a simple task, but it requires that we integrate many quality-related activities with product characteristics, process organization, available resources and skills, and budget constraints.This paper discusses the main characteristics of a good quality process, then surveys the key testing phases and presents modern functional and model-based testing approaches.     

Σynergos—Synergetic Vision Research

This paper reports the development of a powerful andversatile laboratory for vision research, namely ynergos,which has been developed and implemented under Delphi/Windowsin a distributed systems of microcomputers. The main paradigmunderlying the whole approach consists in integrating severalconcepts and techniques into a single computing environment,i.e. ynergos, in such a way that the requisitesand possibilities of each of the constituent components complementone another and the thus obtained result becomes greater thanthe sum of its parts. The components of ynergosinclude distributed system capabilities and a number of librariescontaining algorithms for: computer vision, modeling and simulationof biological visual systems, data and classification analysis,software validation and comparative evaluation, Internet, off-the-shelfapplication, image databases, artificial intelligence, data mining,and visualization resources. In this paper special emphasis isplaced upon the Internet, distributed implementation and biologicalvision. After outlining the principal requisites and potentialsunderlying each of such components, some specific situationsof interest arising from the integration of two or more of suchelements are described and discussed. Details concerning theintegration with Internet and the implementation of the laboratoryas a distributed system are provided, and a complete case-exampleis presented. This applications regards the implementation ofa psychophysical experiment aimed at investigating human perceptionof pictorial complexity, including the derivation of a mathematic-computationalframework modeling such a perception as well as the use of theInternet as a source of stimuli and for reporting the obtainedresults. In addition, the mathematic-computational model is derivedby using a parallel version of the genetic algorithm runningon the distributed system of PCs. The obtained encouraging resultssubstantiate the potential of this vision laboratory for multidisciplinaryvision research.     

Evaluation of a grid based molecular dynamics approach for polypeptide simulations

Molecular dynamics is very important for biomedical research because it makes possible simulation of the behavior of a biological macromolecule in silico. However, molecular dynamics is computationally rather expensive: the simulation of some nanoseconds of dynamics for a large macromolecule such as a protein takes very long time, due to the high number of operations that are needed for solving the Newton's equations in the case of a system of thousands of atoms. In order to obtain biologically significant data, it is desirable to use high-performance computation resources to perform these simulations. Recently, a distributed computing approach based on replacing a single long simulation with many independent short trajectories has been introduced, which in many cases provides valuable results. This study concerns the development of an infrastructure to run molecular dynamics simulations on a grid platform in a distributed way. The implemented software allows the parallel submission of different simulations that are singularly short but together bring important biological information. Moreover, each simulation is divided into a chain of jobs to avoid data loss in case of system failure and to contain the dimension of each data transfer from the grid. The results confirm that the distributed approach on grid computing is particularly suitable for molecular dynamics simulations thanks to the elevated scalability.     

Experimental study of the thermo-mechanical properties of recycled PET fiber-reinforced concrete

This work presents an experimental study of thermal conductivity, compressive strength, first crack strength and ductility indices of recycled PET fiber-reinforced concrete (RPETFRC). We examine PET filaments industrially extruded from recycled PET bottle flakes with different mechanical properties and profiles. On considering a volumetric fiber dosage at 1%, we observe marked improvements in thermal resistance, mechanical strengths and ductility of RPETFRC, as compared to plain concrete. A comparative study with earlier literature results indicates that RPETFRC is also highly competitive over polypropylene-fiber-reinforced concrete in terms of compressive strength and fracture toughness.     

Cadmium adsorption by coal combustion ashes-based sorbents--relationship between sorbent properties and adsorption capacity

A very interesting possibility of coal combustion ashes reutilization is their use as adsorbent materials, that can also take advantage from proper beneficiation techniques. In this work, adsorption of cadmium from aqueous solutions was taken into consideration, with the emphasis on the intertwining among waste properties, beneficiation treatments, properties of the beneficiated materials and adsorption capacity. The characterization of three solid materials used as cadmium sorbents (as-received ash, ash sieved through a 25 μm-size sieve and demineralized ash) was carried out by chemical analysis, infrared spectroscopy, laser granulometry and mercury porosimetry. Cadmium adsorption thermodynamic and kinetic tests were conducted at room temperature, and test solutions were analyzed by atomic absorption spectrophotometry. Maximum specific adsorption capacities resulted in the range 0.5-4.3 mg g(-1). Different existing models were critically considered to find out an interpretation of the controlling mechanism for adsorption kinetics. In particular, it was observed that for lower surface coverage the adsorption rate is governed by a linear driving force while, once surface coverage becomes significant, mechanisms such as the intraparticle micropore diffusion may come into play. Moreover, it was shown that both external fluid-to-particle mass transfer and macropore diffusion hardly affect the adsorption process, which was instead regulated by intraparticle micropore diffusion: characteristic times for this process ranged from 4.1 to 6.1d, and were fully consistent with the experimentally observed equilibrium times. Results were discussed in terms of the relationship among properties of beneficiated materials and cadmium adsorption capacity. Results shed light on interesting correlations among solid properties, cadmium capture rate and maximum cadmium uptake.     

A Parallel Tester Architecture for Accelerometer and Gyroscope MEMS Calibration and Test

This paper describes a tester architecture for Accelerometer and Gyroscope Micro-ElectroMechanical System (MEMS) devices test and calibration, allowing increased parallelism rate and process accuracy. The proposed tester architecture tackles some critical issues related to MEMS testing, such as mitigating mechanical concerns that potentially impact on the equipment Mean Time Between Maintenance and guaranteeing a sufficient number of measurements in the time unit. The proposed strategy consists in an innovative and low cost tester resource partitioning that overcomes current limitations to multisite Accelerometer and Gyroscope MEMS testing. A tester prototype was implemented exploiting FPGAs; feasibility and effectiveness of the proposed methodology was demonstrated on commercial accelerometer and gyroscope MEMS devices.     

Optimization of the extraction of flavanols and anthocyanins from the fruit pulp of Euterpe edulis using the response surface methodology

The response surface methodology (RSM) was employed to optimize the ultrasound extraction of flavanols and anthocyanins from the pulp of jussara (Euterpe edulis), using a second-order polynomial equation to describe the experimental data for total flavanol (TF), total phenolic (TP), and total monomeric anthocyanin (TMA) contents, as well as the total antioxidant activity (TAA). A central composite design with two-variables (extraction time and solid to liquid ratio) was then applied. The optimized conditions that maximized the yields of flavanol-enriched extract were a solvent methanol/0.1 M HCl, solid to liquid ratio of between 1:50 and 1:100 and extraction time of 15 min. For anthocyanin-enriched extracts the respective optimal parameters were a solvent methanol/1.5 M HCl, solid to liquid ratio of between 1:30 and 1:50 and extraction time of 24 h. The results showed good fits with the proposed model for both the flavanol-enriched extract (R² = 0.94) and for the anthocyanin-enriched extract (R² = 0.99).     

The Potential of NanoCellulose in the Packaging Field: A Review

Nanocellulose has potential applications across several industrial sectors and allows the development of innovative materials, as well as the enhancement of conventional materials properties. The nanocellulose particles can be utilized as fillers, in composites manufacture, as coating and as self‐standing thin films, achieving always very interesting and promising properties. Very few of the several reviews that recently appeared on this topic in the scientific literature, however, summarized the potential of cellulose in nanoform specifically for the packaging field rather focusing on different aspects, ranging from the chemistry and the morphology of nanocellulose particles to the preparation methods, the industrial applications and the patents released. In the present review, the remarkable chemical and physical properties of nanocellulose are introduced and discussed with specific reference to the packaging needs. First, the cellulose resources and structure are introduced, then the process methods to reach the nanoscale, the corresponding morphologies and nomenclatures are summarized, mentioning also the possible chemical modifications of nanocellulose and, finally, its practical and potential applications for packaging materials, especially food packaging materials, are tentatively proposed and discussed. Although the review might not cover every aspect on nanocellulose, yet the key points, particularly those related to safety and biodegradability issues, are regarded and considered. Copyright © 2015 John Wiley & Sons, Ltd.     

144 Channel measurement IC for CdZnTe sensors with energy and time resolution

A 144 channel measurement IC for CdZnTe detectors, used for PET, is presented. Each channel consists of a charge sensitive amplifier, a fast and a slow shaper, a peak sampler for the energy acquisition and an event detector based on a time to digital converter to generate an accurate time stamp for each event. The channels are multiplexed to a fast pipeline ADC on demand. Measurement results for the ASIC showed a noise equivalent input charge of 800 e⁻ rms and a time resolution of 737 ps rms. Evaluation results with a CdZnTe detector yielded an energy resolution of 4.4% full width half maximum at 662 keV with a ¹³⁷Cs radiation source. The IC is implemented on a 180 nm CMOS process with a total chip size of 100 mm².