Statistics in the Big Data era

It is estimated that about 90% of the currently available data have been produced over the last two years. Of these, only 0.5% is effectively analysed and used. However, this data can be a great wealth, the oil of 21st century, when analysed with the right approach. In this article, we illustrate some specificities of these data and the great interest that they can represent in many fields. Then we consider some challenges to statistical analysis that emerge from their analysis, suggesting some strategies

Deep learning for supervised classification

One of the most recent area in the Machine Learning research is Deep Learning. Deep Learning algorithms have been applied successfully to computer vision, automatic speech recognition, natural language processing, audio recognition and bioinformatics. The key idea of Deep Learning is to combine the best techniques from Machine Learning to build powerful general‑purpose learning algorithms. It is a mistake to identify Deep Neural Networks with Deep Learning Algorithms. Other approaches are possible, and in this paper we illustrate a generalization of Stacking which has very competitive performances. In particular, we show an application of this approach to a real classification problem, where a three-stages Stacking has proved to be very effective

Categorical Encoding for Machine Learning

Abstract: In recent years, interest has grown in addressing the problem of encoding categorical variables, especially in deep learning applied to big-data. However, the current proposals are not entirely satisfactory. The aim of this work is to show the logic and advantages of a new encoding method that takes its cue from the recent word embedding proposals and which we have called Categorical Embedding. Both a supervised and an unsupervised approach will be considered

Damaging micromechanisms in an as cast ferritic and a ferritized ductile cast iron

Mechanical behavior and damaging micromechanisms in Ductile Cast Irons (DCIs) are strongly effected by matrix microstructure (e.g., phases volume fraction, grains size and grain distribution) and graphite nodules morphology peculiarities (e.g., nodularity level, nodule size, nodule count, etc.). The influence of the graphite nodules depends on both the matrix microstructure and the loading conditions (e.g., quasi-static, dynamic or cyclic loadings). According to the most recent results, these graphite nodules show a mechanical properties gradient inside the graphite nodules, with the graphite elements – matrix debonding as only one of the possible damaging micromechanisms. In this work, two different ferritic DCIs were investigated (a ferritic matrix obtained from as-cast condition and a ferritized matrix) focusing on the damaging micromechanisms in graphite nodules due to tensile stress. Specimens lateral surfaces were observed using a Scanning Electron Microscope (SEM) during the tests following a step by step procedure.Fil: D' Agostino, Laura. Università di Cassino e del Lazio Meridionale; ItaliaFil: Di Cocco, Vittorio. Università di Cassino e del Lazio Meridionale; ItaliaFil: Fernandino, Diego Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y Tecnología de Materiales. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Instituto de Investigaciones en Ciencia y Tecnología de Materiales; ArgentinaFil: Lacoviello, Francesco. Università di Cassino e del Lazio Meridionale; Itali

Extended pelvic lymph node dissection at the time of robot-assisted radical prostatectomy: Impact of surgical volume on efficacy and complications in a single-surgeon series

INTRODUCTION: We assessed the impact of surgical volume on perioperative outcomes and complications of robotic extended pelvic lymph node dissection (ePLND). METHODS: From November 2008 to October 2012, a total of 233 consecutive patients with intermediate- or high-risk clinically localized prostate cancer underwent robot-assisted radical prostatectomy (RARP) and ePLND by a single, experienced open and laparoscopic surgeon. Data were prospectively collected. Complications were classified according to the Modified Clavien System. Complications potentially related to ePLND were documented. The minimum follow-up was 3 months. To evaluate the impact of surgical volume on the results, 4 patient subgroups (subgroup 1: cases 1-59; 2: 60-117; 3: 118-175; 4: 176-233) were compared using the Chi-squared and Kruskal-Wallis tests. RESULTS: The mean (range) operative time for ePLND was 79 minutes (range: 48-144), with a steady performance over time (p = 0.784). The count of resected lymph nodes plateaued after 60 procedures (mean [range]: 13 [range: 6-32], 15 [range: 7-34], 17 [range: 8-41], 16 [range: 8-42] in Groups 1 to 4, respectively, p = 0.001). Tumour lymph node involvement was 12% in Groups 1 and 2, 7% in Group 3 and 9% in Group 4 (p = 0.075). Overall, 115 complications were reported in 98/233 patients (42%), with a significant decrease after 175 cases (p = 0.028). In Group 4, 3 patients reported an ePLND-related bleeding requiring open revision. Lymphoceles were detected in 10/233 patients (4.2%) and 1 patient (1.7%) in each of the Groups 2 to 4 required a percutaneous drainage. CONCLUSIONS: A surgeon with extensive experience is expected to achieve a safe learning curve for ePLND during RARP. A learning curve of 60 cases is suggested for optimal lymph node yield

Optimal fault-tolerant placement of relay nodes in a mission critical wireless network

The operations of many critical infrastructures (e.g., airports) heavily depend on proper functioning of the radio communication network supporting operations. As a result, such a communication network is indeed a mission-critical communication network that needs adequate protection from external electromagnetic interferences. This is usually done through radiogoniometers. Basically, by using at least three suitably deployed radiogoniometers and a gateway gathering information from them, sources of electromagnetic emissions that are not supposed to be present in the monitored area can be localised. Typically, relay nodes are used to connect radiogoniometers to the gateway. As a result, some degree of fault-tolerance for the network of relay nodes is essential in order to offer a reliable monitoring. On the other hand, deployment of relay nodes is typically quite expensive. As a result, we have two conflicting requirements: minimise costs while guaranteeing a given fault-tolerance. In this paper address the problem of computing a deployment for relay nodes that minimises the relay node network cost while at the same time guaranteeing proper working of the network even when some of the relay nodes (up to a given maximum number) become faulty (fault-tolerance). We show that the above problem can be formulated as a Mixed Integer Linear Programming (MILP) as well as a Pseudo-Boolean Satisfiability (PB-SAT) optimisation problem and present experimental results com- paring the two approaches on realistic scenarios

I quanta acustici di Gabor nelle tecnologie del suono e della musica

Through a series of brillant paper publications dating from the late 1940s, Dennis Gabor developed a new conceptual and operational framework for the analysis of sound signals, based on a quantum-oriented view of acoustical phenomena. In the present essay, I try to illustrate the shaping up of Gabor’s quantum analysis of sound, especially as delineated in two papers from 1946 (Theory of communication) and 1947 (Acoustical quanta and the theory of hearing), and to overview its legacy in scientific research as well as in audio and musical applications. After some introductory remarks, I follow a hybrid path, between history of science and history of audio technology, sketching a “genealogy” of Gabor’s quantum view of sound (i.e. as connected to Heisenberg’s indeterminacy principle, to Mach’s analysis of sensation, etc.), and relating it to an empiricist tradition of modern science. I eventually situate his research in the context of contemporary research preoccupations shared by other, at the time, and I finally discuss some of the earliest audio devices that seem to tie back to Gabor’s own practical experiments (beside his theoretical framework) and that revealed of primary interest to pioneers in analog and digital music technologies and related creative practices