Grid Infrastructure for Domain Decomposition Methods in Computational ElectroMagnetics

The accurate and efficient solution of Maxwell's equation is the problem addressed by the scientific discipline called Computational ElectroMagnetics (CEM). Many macroscopic phenomena in a great number of fields are governed by this set of differential equations: electronic, geophysics, medical and biomedical technologies, virtual EM prototyping, besides the traditional antenna and propagation applications. Therefore, many efforts are focussed on the development of new and more efficient approach to solve Maxwell's equation. The interest in CEM applications is growing on. Several problems, hard to figure out few years ago, can now be easily addressed thanks to the reliability and flexibility of new technologies, together with the increased computational power. This technology evolution opens the possibility to address large and complex tasks. Many of these applications aim to simulate the electromagnetic behavior, for example in terms of input impedance and radiation pattern in antenna problems, or Radar Cross Section for scattering applications. Instead, problems, which solution requires high accuracy, need to implement full wave analysis techniques, e.g., virtual prototyping context, where the objective is to obtain reliable simulations in order to minimize measurement number, and as consequence their cost. Besides, other tasks require the analysis of complete structures (that include an high number of details) by directly simulating a CAD Model. This approach allows to relieve researcher of the burden of removing useless details, while maintaining the original complexity and taking into account all details. Unfortunately, this reduction implies: (a) high computational effort, due to the increased number of degrees of freedom, and (b) worsening of spectral properties of the linear system during complex analysis. The above considerations underline the needs to identify appropriate information technologies that ease solution achievement and fasten required elaborations. The authors analysis and expertise infer that Grid Computing techniques can be very useful to these purposes. Grids appear mainly in high performance computing environments. In this context, hundreds of off-the-shelf nodes are linked together and work in parallel to solve problems, that, previously, could be addressed sequentially or by using supercomputers. Grid Computing is a technique developed to elaborate enormous amounts of data and enables large-scale resource sharing to solve problem by exploiting distributed scenarios. The main advantage of Grid is due to parallel computing, indeed if a problem can be split in smaller tasks, that can be executed independently, its solution calculation fasten up considerably. To exploit this advantage, it is necessary to identify a technique able to split original electromagnetic task into a set of smaller subproblems. The Domain Decomposition (DD) technique, based on the block generation algorithm introduced in Matekovits et al. (2007) and Francavilla et al. (2011), perfectly addresses our requirements (see Section 3.4 for details). In this chapter, a Grid Computing infrastructure is presented. This architecture allows parallel block execution by distributing tasks to nodes that belong to the Grid. The set of nodes is composed by physical machines and virtualized ones. This feature enables great flexibility and increase available computational power. Furthermore, the presence of virtual nodes allows a full and efficient Grid usage, indeed the presented architecture can be used by different users that run different applications

Virtual Environment for Next Generation Sequencing Analysis

Next Generation Sequencing technology, on the one hand, allows a more accurate analysis, and, on the other hand, increases the amount of data to process. A new protocol for sequencing the messenger RNA in a cell, known as RNA- Seq, generates millions of short sequence fragments in a single run. These fragments, or reads, can be used to measure levels of gene expression and to identify novel splice variants of genes. The proposed solution is a distributed architecture consisting of a Grid Environment and a Virtual Grid Environment, in order to reduce processing time by making the system scalable and flexibl

Reverse Engineering of TopHat: Splice Junction Mapper for Improving Computational Aspect

TopHat is a fast splice junction mapper for Next Generation Sequencing analysis, a technology for functional genomic research. Next Generation Sequencing technology allows more accurate analysis increasing data to elaborate, this opens to new challenges in terms of development of tools and computational infrastructures. We present a solution that cover aspects both software and hardware, the first one, after a reverse engineering phase, provides an improvement of algorithm of TopHat making it parallelizable, the second aspect is an implementation of an hybrid infrastructure: grid and virtual grid computing. Moreover the system allows to have a multi sample environment and is able to process automatically totally transparent to user

Seismic Behavior of RC Beam-Column Subassemblages with Flat Beam

More reliable assessment procedures of existing RC buildings are currently available, and have been introduced in the Italian and European codes reporting new rules for seismic design and analysis. However, further studies are necessary in order to upgrade such procedures and, specifically, obtain more detailed information on the behaviour of beam-column joints, whose role on the global behaviour of framed RC buildings can be crucial. Until now studies on this issue have been mainly devoted to joint specimens with rigid beams, however joint specimens having flat (flexible) beams are widely used in the European residential RC buildings. To this purpose, given the lack of knowledge, an experimental investigation on full scale beam-column joints with flat beam has been planned and is currently in progress. In the present paper the first results of four tests are reported and discussed

Influence of Axial Load on the Seismic Behavior of RC Beam-Column Joints with Wide Beam

Beam-column joints can play a key role on the seismic behavior of reinforced concrete buildings. Until now studies and experimental investigations on this topic have been mainly focused on beam-column joints with stiff beams, i.e. beams with height larger than the thickness of the adjacent floor slab. However, especially in the European residential building stock, frame structures are often equipped with wide - therefore rather flexible - beams. However, not many studies have been devoted so far to this type of connection, therefore an experimental investigation on full scale beam-column joints with wide beam was planned at the University of Basilicata and is currently in progress. In the present paper the main results of two cyclic tests are reported and discussed specifically analyzing the role of the axial load applied to the column on the joint performances and damage mechanisms. Test results highlights that the axial load value has a significant influence of on deformation capacity and ductility behavior

Viable seismic strengthening solutions for RC wide beam-column joints

Beam-column joints play a key role on the seismic behavior of reinforced concrete buildings. Many of these buildings, although they belong to earthquake prone countries, were designed only to withstand gravity loads, thus without appropriate strength and ductility capacity with respect to seismic actions. Beam-column joints with flat or wide beam are rather widespread in the European residential building stock. Contrarily to joints provided with stiff beams, there are a few studies devoted to evaluate their performance and, especially, the arrangement and effectiveness of strengthening solutions for this type of joints. For this reason an experimental program has been setup in order to evaluate the effectiveness of simple and easy to apply strengthening techniques derived from the CAM technique. Three identical specimens were tested, one in the as-built condition and two specimens after the application of steel based strengthening solutions. The present paper shows a preliminary analysis of the test results highlighting the effectiveness of the techniques proposed in improving the seismic behavior of the specimens under study

Validating of a new procedure for damage localization using shaking table tests on a 1:15 scaled structure

In Earthquake Engineering field, due to the complexity of the phenomena that characterize the behaviour of structures and their interaction with the foundation soil, the recourse to experimental research is necessary to better understand the mechanical behaviour of the various structural and non-structural components, to validate new techniques for Structural Health Monitoring and for damage detection and localization. Aim of this paper is to present the preliminary results retrieved from an experimental campaign performed on a five-floor 1:15 scaled structure excited using several shaking-table tests in order to validate an innovative methodology for damage localization