399 research outputs found
ReForeSt: Random forests in apache spark
Random Forests (RF) of tree classifiers are a popular ensemble method for classification. RF are usually preferred with respect to other classification techniques because of their limited hyperparameter sensitivity, high numerical robustness, native capacity of dealing with numerical and categorical features, and effectiveness in many real world classification problems. In this work we present ReForeSt, a Random Forests Apache Spark implementation which is easier to tune, faster, and less memory consuming with respect to MLlib, the de facto standard Apache Spark machine learning library. We perform an extensive comparison between ReForeSt and MLlib by taking advantage of the Google Cloud Platform (https://cloud.google.com). In particular, we test ReForeSt and MLlib with different library settings, on different real world datasets, and with a different number of machines equipped with different number of cores. Results confirm that ReForeSt outperforms MLlib in all the above mentioned aspects. ReForeSt is made publicly available via GitHub (https://github.com/alessandrolulli/reforest)
Resistencia de quince variedades de arroz (Oryza sativa L.) al virus Hoja Blanca y al vector Sogatodes oryzicolus Muir.
Relaciona la resistencia de un grupo de variedades de arroz al virus hoja blanca y al insecto vector Sogatodes oryzicolus para determinar una posible correlación entre estas dos características. Se realizó bajo condiciones de invernadero en el Centro de Investigaciones Tibaitatá, con temperatura entre 17 y 33 grados centigrados y humedad relativa de 56 a 100 por ciento. Se emplearon 15 variedades de arroz, y de un arrozal de Nataima, fueron recolectados aproximadamente 500 insectos entre ninfas y adultos. Las variedades ICA-10, ICA-3, Nilo 3A y Napal fueron resistentes al virus hoja blanca; IR-8 fué resistente al S. oryzicolus; Mudgo e IR 5 fueron resistentes tanto al virus como al vector. No se encontró correlación entre resistencia al virus hoja blanca y resistencia al vector. Los adultos hembras y ninfas fueron los que más daño ocasionaron a las plantas de arroz. Tratando de explicar los efectos de las variedades resistentes en la biología del insecto, se encontró que estos sobreviven menos en las variedades resistentes, hay menor oviposición y progenie y el peso del insecto es menorArroz-Oryza sativaMaestría en CienciasMaestrí
Diet of a restocked population of the European pond turtle Emys orbicularis in NW Italy
Recently several projects have been implemented for the conservation of the European turtle Emys orbicularis, but few aspects of the captive-bred animals released into the wild have been described. In this note we report about the trophic habits of a small restocked population of the endemic subspecies E. o. ingauna that is now reproducing in NW Italy. Faecal contents from 25 individuals (10 females, 11 males and 4 juveniles) were obtained in June 2016. Overall, 11 taxonomic categories of invertebrates were identified, together with seeds and plant remains. Plant material was present in 24 out of 25 turtle faecal contents, suggesting that ingestion was deliberate. There were no differences between the dietary habits of females and males, and the trophic strategy of adult individuals was characterised by a relatively high specialization on dragonfly nymphae. These findings suggest that captive bred turtles are adapting well to the wild and that restocked individuals assumed an omnivorous diet, a trophic behaviour typical of other wild turtle populations living in similar habitats
Energy Efficient Smartphone-Based Activity Recognition Using Fixed-Point Arithmetic
In this paper we propose a novel energy efficient approach for the recog- nition of human activities using smartphones as wearable sensing devices, targeting assisted living applications such as remote patient activity monitoring for the disabled and the elderly. The method exploits fixed-point arithmetic to propose a modified multiclass Support Vector Machine (SVM) learning algorithm, allowing to better pre- serve the smartphone battery lifetime with respect to the conventional floating-point based formulation while maintaining comparable system accuracy levels. Experiments show comparative results between this approach and the traditional SVM in terms of recognition performance and battery consumption, highlighting the advantages of the proposed method
Comparison between Two Different Two-Stage Transperineal Approaches to Treat Urethral Strictures or Bladder Neck Contracture Associated with Severe Urinary Incontinence that Occurred after Pelvic Surgery: Report of Our Experience
Introduction. The recurrence of urethral/bladder neck stricture after multiple endoscopic procedures is a rare complication that can follow prostatic surgery and its treatment is still controversial. Material and Methods. We retrospectively analyzed our data on 17 patients, operated between September 2001 and January 2010, who presented severe urinary incontinence and urethral/bladder neck stricture after prostatic surgery and failure of at least four conservative endoscopic treatments. Six patients underwent a transperineal urethrovesical anastomosis and 11 patients a combined transperineal suprapubical (endoscopic) urethrovesical anastomosis. After six months the patients that presented complete incontinence and no urethral stricture underwent the implantation of an artificial urethral sphincter (AUS). Results. After six months 16 patients were completely incontinent and presented a patent, stable lumen, so that they underwent an AUS implantation. With a mean followup of 50.5 months, 14 patients are perfectly continent with no postvoid residual urine. Conclusions. Two-stage procedures are safe techniques to treat these challenging cases. In our opinion, these cases could be managed with a transperineal approach in patients who present a perfect operative field; on the contrary, in more difficult cases, it would be preferable to use the other technique, with a combined transperineal suprapubical access, to perform a pull-through procedure
A communication platform demonstrator for new generation railway traffic management systems: Testing and validation
Current rail traffic management and control systems cannot be easily upgraded to the new needs and challenges of modern railway systems because they do not offer interoperable data structures and standardized communication interfaces. To meet this need, the Horizon 2020 Shift2Rail OPTIMA project has developed a communication platform for testing and validating the new generation of traffic management systems (TMS), whose main innovative features are the interoperability of the data structures used, standardization of communications, continuous access to real-time and persistent data from heterogeneous data sources, modularity of components and scalability of the platform. This paper presents the main components, their functions and characteristics, then describes the testing and validation of the platform, even when federated with other innovative TMS modules developed in separate projects. The successful validation of the system has confirmed the achievement of the objectives set and allowed a new set of objectives to be defined for the reference platform for the railway TMS/Traffic Control systems
Evaluation of a geometry-based knee joint compared to a planar knee joint
peer reviewedToday neuromuscular simulations are used in sev- eral fields, such as diagnostics and planing of surgery, to get a deeper understanding of the musculoskeletal system. Dur- ing the last year, new models and datasets have been pre- sented which can provide us with more in-depth simulations and results. The same kind of development has occurred in the field of studying the human knee joint using complex three dimensional finite element models and simulations. In the field ofmusculoskeletal simulations, no such knee joints can be used. Instead themost common knee joint description is an idealized knee joint with limited accuracy or a planar knee joint which only describes the knee motion in a plane. In this paper, a new knee joint based on both equations and geometry is introduced and compared to a common clinical planar knee joint. The two kinematical models are analyzed using a gait motion, and are evaluated using the muscle ac- tivation and joint reaction forces which are compared to in- vivo measured forces. We show that we are able to predict the lateral, anterior and longitudinal moments, and that we are able to predict better knee and hip joint reaction forces
So close so different: what makes the difference?
The introduction of alien fish species in wetland ecosystems could have a great impact on freshwater communities
and ecological processes. Despite fish introduction has been noticed as one of the principal cause of freshwater
extinctions, ecosystem processes alteration, and change in aquatic community assemblage, very few data about
impact on freshwater reptiles are available. As study model we used two neighbour sub-populations of the endangered
Sicilian pond turtle, Emys trinacris, inhabiting two small, close each other and very similar lakes, except for the presence
of allocthonous fish, Cyprinus carpio and Gambusia hoolbroki in one of the two. The multi-year study allowed
highlighting significant differences in abundance, growth and reproductive output between the two freshwater turtle
sub-populations, suggesting their influence on phenotypic plasticity of the studied population. These results are
discussed in the light of previous evidence about the impact of these alien species on abundance and assemblage of
the invertebrate community with an evident impact on niche width, diet composition and therefore energy intake by
Emys trinacris. These data may provide important information to address management strategies and conservation
actions of small wetland areas inhabited by pond turtles, pointing out a threats never highlighted up to now
Societal issues in machine learning: When learning from data is not enough
It has been argued that Artificial Intelligence (AI) is experiencing a fast process of commodification. Such characterization is on the interest of big IT companies, but it correctly reflects the current industrialization of AI. This phenomenon means that AI systems and products are reaching the society at large and, therefore, that societal issues related to the use of AI and Machine Learning (ML) cannot be ignored any longer. Designing ML models from this human-centered perspective means incorporating human-relevant requirements such as safety, fairness, privacy, and interpretability, but also considering broad societal issues such as ethics and legislation. These are essential aspects to foster the acceptance of ML-based technologies, as well as to ensure compliance with an evolving legislation concerning the impact of digital technologies on ethically and privacy sensitive matters. The ESANN special session for which this tutorial acts as an introduction aims to showcase the state of the art on these increasingly relevant topics among ML theoreticians and practitioners. For this purpose, we welcomed both solid contributions and preliminary relevant results showing the potential, the limitations and the challenges of new ideas, as well as refinements, or hybridizations among the different fields of research, ML and related approaches in facing real-world problems involving societal issues
- …