Tiziano Leidi

Design and implementation of industrial automation control systems: A survey

The level of automation in factories and plants, and the need for their fast design and customization, increases steadily. These systems are often designed with various means, and controlled by heterogeneous embedded hard- and software. These circumstances raise the problem complexity and the time to be invested. The state-of-the art and the trends in design and engineering for the industrial automation have not yet provided an applicable solution to the mentioned issues. Hence a new European project tries to overcome the previous problems with a new component based approach for automatically linking the design and implementation phases. This document resumes and analyses the results of a survey conducted among the project industrial partners about their current design and implementation processes. What emerges is the need and the lack of connection, and even transformation rules, between the two aforementioned processes.

Surface Growth Effects On Reactive Capillary-Driven Flow: Lattice Boltzmann Investigation

Abstract The Washburn law has always played a critical role for ceramics. In the microscale, surface forces take over volume forces and the phenomenon of spontaneous infiltration in narrow interstices becomes of particular relevance. The Lattice Boltzmann method is applied in order to ascertain the role of surface reaction and subsequent deformation of a single capillary in 2D for the linear Washburn behavior. The proposed investigation is motivated by the problem of reactive infiltration of molten silicon into carbon preforms. This is a complex phenomenon arising from the interplay between fluid flow, the transition to wetting, surface growth and heat transfer. Furthermore, it is characterized by slow infiltration velocities in narrow interstices resulting in small Reynolds numbers that are difficult to reproduce with a single capillary. In our simulations, several geometric characteristics for the capillaries are considered, as well as different infiltration and reaction conditions. The main result of our work is that the phenomenon of pore closure can be regarded as independent of the infiltration velocity, and in turn a number of other parameters. The instrumental conclusion drawn from our simulations is that short pores with wide openings and a round-shaped morphology near the throats represent the optimal configuration for the underlying structure of the porous preform in order to achieve faster infiltration. The role of the approximations is discussed in detail and the robustness of our findings is assessed.

Lattice Boltzmann simulations on the role of channel structure for reactive capillary infiltration

It is widely recognized that the structure of porous media is of relevance for a variety of mechanical and physical phenomena. The focus of the present work is on capillarity, a pore-scale process occurring at the micron scale. We attempt to characterize the influence of pore shape for capillary infiltration by means of Lattice Boltzmann simulations in 2D with reactive boundaries leading to surface growth and ultimately to pore closure. The systems under investigation consist of single channels with different simplified morphologies: namely, periodic profiles with sinusoidal, step-shaped and zigzag walls, as well as constrictions and expansions with rectangular, convex and concave steps. This is a useful way to break the complexity of typical porous media down into basic structures. The simulations show that the minimum radius alone fails to properly characterize the infiltration dynamics. The structure of the channels emerges as the dominant property controlling the process. A factor responsible for this behavior is identified as being the occurrence of the pinning of the contact line. It turns out that the optimal configuration for the pore structure arises from the packing of large particles with round shapes. In this case, the probability of having wide and straight flow paths is higher. Faceted surfaces with sharp edges should be avoided because of the phenomenon of pinning near narrow-to-wide parts. This study is motivated by the infiltration of molten metals into carbon preforms. This is a manufacturing technique for ceramic components devised for advanced applications. Guidelines for experimental work are discussed.

Event-driven Scheduling for Parallel Stream Processing

To optimize real-time stream-processing applications for chip-level multi processors, several challenges have to be met. Poor scalability and poor internal data pressure may result from serial dependencies within or between the algorithms. Load imbalances introduced by the parallel-processing hardware and execution environment may also limit performance. To maximize the throughput and minimize the latency of parallel stream-processing applications, we propose an approach that complements run-time dynamic load balancing with static pre-compile partitioning. In our solution, the dynamic features are based on event-driven scheduling, while the static features benefit from profile-guided automatic optimizations. In this paper, we present some recent enhancements of DSPE, an open-source development environment, featuring model and source code generators for prototyping, refining and customizing real-time stream-processing applications. By using our approach on micro-benchmarks and sample applications, we also show that it is possible to reduce the impact of the different speed-up constrainers.

CEC designer: Domain specific modelling for the industrial automation based on the IEC 61499 standard

Support for evolutionary design approaches is not a very much investigated topic in the automation domain. Advanced facilities for semantic validation, refactoring and model transformations, which are necessary for rapid prototyping of control applications, are seldom found in design tools. Implementing such facilities is even more difficult when using the IEC 61499 standard, through some characteristics of the persistence model. This paper presents a specialized development environment for modelling and automatically generating applications for the industrial automation field, its unique facilities for supporting evolutionary design and the suggested improvements to the IEC 61499 model. This environment was developed inside a project for assessing the IEC 61499 principles and for verifying design approaches and execution models on a real plant.

Computing effective properties of random heterogeneous materials on heterogeneous parallel processors

In recent decades, finite element (FE) techniques have been extensively used for predicting effective properties of random heterogeneous materials. In the case of very complex microstructures, the choice of numerical methods for the solution of this problem can offer some advantages over classical analytical approaches, and it allows the use of digital images obtained from real material samples (e.g., using computed tomography). On the other hand, having a large number of elements is often necessary for properly describing complex microstructures, ultimately leading to extremely time-consuming computations and high memory requirements. With the final objective of reducing these limitations, we improved an existing freely available FE code for the computation of effective conductivity (electrical and thermal) of microstructure digital models. To allow execution on hardware combining multi-core CPUs and a GPU, we first translated the original algorithm from Fortran to C, and we subdivided it into software components. Then, we enhanced the C version of the algorithm for parallel processing with heterogeneous processors. With the goal of maximizing the obtained performances and limiting resource consumption, we utilized a software architecture based on stream processing, event-driven scheduling, and dynamic load balancing. The parallel processing version of the algorithm has been validated using a simple microstructure consisting of a single sphere located at the centre of a cubic box, yielding consistent results. Finally, the code was used for the calculation of the effective thermal conductivity of a digital model of a real sample (a ceramic foam obtained using X-ray computed tomography). On a computer equipped with dual hexa-core Intel Xeon X5670 processors and an NVIDIA Tesla C2050, the parallel application version features near to linear speed-up progression when using only the CPU cores. It executes more than 20 times faster when additionally using the GPU.

OMEGA: a software tool for the management, analysis, and dissemination of intracellular trafficking data that incorporates motion type classification and quality control

MOTIVATION Particle tracking coupled with time-lapse microscopy is critical for understanding the dynamics of intracellular processes of clinical importance. Spurred on by advances in the spatiotemporal resolution of microscopy and automated computational methods, this field is increasingly amenable to multi-dimensional high-throughput data collection schemes (Snijder et al., 2012). Typically, complex particle tracking datasets generated by individual laboratories are produced with incompatible methodologies that preclude comparison to each other. There is therefore an unmet need for data management systems that facilitate data standardization, meta-analysis, and structured data dissemination. The integration of analysis, visualization, and quality control capabilities into such systems would eliminate the need for manual transfer of data to diverse downstream analysis tools. At the same time, it would lay the foundation for shared trajectory data, particle tracking, and motion analysis standards. RESULTS Here, we present Open Microscopy Environment inteGrated Analysis (OMEGA), a cross-platform data management, analysis, and visualization system, for particle tracking data, with particular emphasis on results from viral and vesicular trafficking experiments. OMEGA provides intuitive graphical interfaces to implement integrated particle tracking and motion analysis workflows while providing easy to use facilities to automatically keep track of error propagation, harvest data provenance and ensure the persistence of analysis results and metadata. Specifically, OMEGA: 1) imports image data and metadata from data management tools such as the Open Microscopy Environment Remote Objects (OMERO; Allan et al., 2012); 2) tracks intracellular particles movement; 3) facilitates parameter optimization and trajectory results inspection and validation; 4) performs downstream trajectory analysis and motion type classification; 5) estimates the uncertainty propagating through the motion analysis pipeline; and, 6) facilitates storage and dissemination of analysis results, and analysis definition metadata, on the basis of our newly proposed FAIRsharing.org complainant Minimum Information About Particle Tracking Experiments (MIAPTE; Rigano and Strambio-De- Castillia, 2016; 2017) guidelines in combination with the OME-XML data model (Goldberg et al., 2005). In so doing, OMEGA maintains a persistent link between raw image data, intermediate analysis steps, the overall analysis output, and all necessary metadata to repeat the analysis process and reproduce its results. Availability and implementation OMEGA is a cross-platform, open-source software developed in Java. Source code and cross-platform binaries are freely available on GitHub at https://github.com/OmegaProject/Omega (doi: 10.5281/zenodo.2535523), under the GNU General Public License v.3. Contact caterina.strambio@umassmed.edu and alex.rigano@umassmed.edu Supplementary information Supplementary Material is available at BioRxiv.org

Simulation of capillary infiltration into packing structures for the optimization of ceramic materials using the lattice Boltzmann method

In this work we want to simulate with the Lattice-Boltzmann method in 2D the capillary infiltration into porous structures obtained from the packing of particles. The experimental problem motivating our work is the densification of carbon preforms by reactive melt infiltration. The aim is to determine optimization principles for the manufacturing of high-performance ceramics. Simulations are performed for packings with varying structural properties. Our analysis suggests that the observed slow infiltrations can be ascribed to interface dynamics. Pinning represents the primary factor retarding fluid penetration. The mechanism responsible for this phenomenon is analyzed in detail. When surface growth is allowed, it is found that the phenomenon of pinning becomes stronger. Systems trying to reproduce typical experimental conditions are also investigated. It turns out that the standard for accurate simulations is challenging. The primary obstacle to overcome for enhanced accuracy seems to be the over-occurrence of pinning.ABSTRACT This study uses the lattice Boltzmann method (LBM) to simulate in 2D the capillary infiltration into porous structures obtained from the packing of particles. The experimental problem motivating the work is the densification of carbon preforms by reactive melt infiltration. The aim is to determine the optimization principles for the manufacturing of high-performance ceramics. Simulations are performed for packings with varying structural properties. The results suggest that the observed slow infiltrations can be ascribed to interface dynamics. Pinning represents the primary factor retarding fluid penetration. The mechanism responsible for this phenomenon is analyzed in detail. When surface growth is allowed, it is found that the phenomenon of pinning becomes stronger. Systems trying to reproduce typical experimental conditions are also investigated. It turns out that the standard for accurate simulations is challenging. The primary obstacle to overcome for enhanced accuracy seems to be the over-occurrence of pinning.

User-profiled platform with advanced navigation support

The increasing spreading of top-medium range mobile phones offering advanced capabilities and the broader use of short-range wireless technologies embedded in them are laying the foundations for the development of new added-value services. In this paper we present an architectural solution for delivering location-based services over heterogeneous mobile phones tailored to the preferences of individual users. We then discuss the performance of a solution for proximity marketing derived from the platform, in terms of localization accuracy and client-application usability.

A Complete Tool-Chain for Developing and TestingWSNApplications with FLEXOR

In this paper, we present the complete tool-chainfor FLEXOR, a sustainable and platform independent softwarearchitecture that is optimized to support the implementation,rapid prototyping, evaluation, and testing of wireless sensornetwork applications. Keywords—Wireless SensorNetworks, Architecture, Tool