Analyzing the presence of noise in multi-class problems: alleviating its influence with the One-vs-One decomposition

The presence of noise in data is a common problem that produces several negative consequences in classification problems. In multi-class problems, these consequences are aggravated in terms of accuracy, building time, and complexity of the classifiers. In these cases, an interesting approach to reduce the effect of noise is to decompose the problem into several binary subproblems, reducing the complexity and, consequently, dividing the effects caused by noise into each of these subproblems. This paper analyzes the usage of decomposition strategies, and more specifically the One-vs-One scheme, to deal with noisy multi-class datasets. In order to investigate whether the decomposition is able to reduce the effect of noise or not, a large number of datasets are created introducing different levels and types of noise, as suggested in the literature. Several well-known classification algorithms, with or without decomposition, are trained on them in order to check when decomposition is advantageous. The results obtained show that methods using the One-vs-One strategy lead to better performances and more robust classifiers when dealing with noisy data, especially with the most disruptive noise schemes.     

Tactile sensors based on conductive polymers

This paper presents results from a selection of tactile sensors that have been designed and fabricated. These sensors are based on a common approach that consists in placing a sheet of piezoresistive material on the top of a set of electrodes. We use a thin film of conductive polymer as the piezoresistive material. Specifically, a conductive water-based ink of this polymer is deposited by spin-coating on a flexible plastic sheet, giving it a smooth, homogeneous and conducting thin film. The main interest in this procedure is that it is cheap and it allows the fabrication of flexible and low cost tactile sensors. In this work, we present results from sensors made using two technologies. Firstly, we have used a flexible printed circuit board (PCB) technology to fabricate the set of electrodes and addressing tracks. The result is a simple, flexible tactile sensor. In addition to these sensors on PCB, we have proposed, designed and fabricated sensors with screen-printing technology. In this case, the set of electrodes and addressing tracks are made by printing an ink based on silver nanoparticles. The exhaustive characterization provides us insights into the design of these tactile sensors.     

An approach based on an adaptive multi-rate smith predictor and gain scheduling for a networked control system: Implementation over Profibus-DP

This paper presents a control strategy to face time-varying delays induced in a Networked Control System (NCS). The delay is divided into two parts: the largest one (an integer multiple of the bus cycle) is compensated by means of an adaptive multi-rate Smith predictor, and the smallest one (whose value is strictly smaller than the bus cycle) via a gain scheduling approach based on root locus contour and linearization techniques. The gains to be scheduled belong to a multi-rate PID controller. Control system stability is studied by means of Lyapunov theory. Simulation results and the implementation on a test-bed Profibus-DP environment illustrate that this control structure can maintain NCS performance and stability, despite the considered delays.     

Rank Estimation in Missing Data Matrix Problems

A novel technique for missing data matrix rank estimation is presented. It is focused on matrices of trajectories, where every element of the matrix corresponds to an image coordinate from a feature point of a rigid moving object at a given frame; missing data are represented as empty entries. The objective of the proposed approach is to estimate the rank of a missing data matrix in order to fill in empty entries with some matrix completion method, without using or assuming neither the number of objects contained in the scene nor the kind of their motion. The key point of the proposed technique consists in studying the frequency behaviour of the individual trajectories, which are seen as 1D signals. The main assumption is that due to the rigidity of the moving objects, the frequency content of the trajectories will be similar after filling in their missing entries. The proposed rank estimation approach can be used in different computer vision problems, where the rank of a missing data matrix needs to be estimated. Experimental results with synthetic and real data are provided in order to empirically show the good performance of the proposed approach.     

GPU-accelerated level-set segmentation

The level-set method, a technique for the computation of evolving interfaces, is a solution commonly used to segment images and volumes in medical applications. GPUs have become a commodity hardware with hundreds of cores that can execute thousands of threads in parallel, and they are nowadays ideal platforms to execute computational intensive tasks, such as the 3D level-set-based segmentation, in real time. In this paper, we propose two GPU implementations of the level-set-based segmentation method called Fast Two-Cycle. Our proposals perform computations in independent domains called tiles and modify the structure of the original algorithm to better exploit the features of the GPU. The implementations were tested with real images of brain vessels and a synthetic MRI image of the brain. Results show that they execute faster than a CPU-sequential implementation of the same method, without any significant loss of the segmentation quality and without requiring distributed parallel computer infrastructures.     

A comparison of path planning strategies for autonomous exploration and mapping of unknown environments

To date, a large number of algorithms to solve the problem of autonomous exploration and mapping has been presented. However, few efforts have been made to compare these techniques. In this paper, an extensive study of the most important methods for autonomous exploration and mapping of unknown environments is presented. Furthermore, a representative subset of these techniques has been chosen to be analysed. This subset contains methods that differ in the level of multi-robot coordination and in the grade of integration with the simultaneous localization and mapping (SLAM) algorithm. These exploration techniques were tested in simulation and compared using different criteria as exploration time or map quality. The results of this analysis are shown in this paper. The weaknesses and strengths of each strategy have been stated and the most appropriate algorithm for each application has been determined.     

王圪堵水库大坝填筑土料配水试验分析

陕北北部地区兴建水利工程,主要建筑材料为风积黄土,由于气候条件的特殊性,土料的物理力学特性具有很大的差异。故施工前对土料的物理、力学特性进行分析研究至关重要。本工程土料的最大特点是含水率低,不能满足填筑要求。为此,对土料进行了专门的配水试验和施工碾压试验,通过试验分析评价,为设计提供可行的开采方案与施工碾压参数。     

Description of the intensive care unit. Hospital de Leon (Leon)

Sirenomelia or the mermaid syndrome is a rare birth defect, often combined with severe malformations of the urogenital system and the lower gastrointestinal tract. The incidence is about one case in 60,000. Ultrasound can be very important in early detection of this deformity. Because of the high incidence of oligohydramnios amnioninfusion could be helpful. Also a magnetic resonance radiographia in the prenatal period could be performed. We report three cases of sirenomelia and in addition the literature is reviewed and discussed.     

A New Process for Exhausting a Permethrin-based Mothproofing Agent on Wool Fibres

To rind appropriate systems to solubilize mothproofing agents and to promote their total exhaustion on wool fibres is essential from the environmental point of view. Since the predominant mechanism for the uptake of a water-insoluble mothproofing agent by the wool fibre is analogous to that of a disperse dyestuff, a permethrin-based mothproofing agent was applied to wool fibres under the same experimental conditions as those previously found suitable for non-ionic disperse agents.

A sodium sulphite/or sodium bisulphite/cationic-surfactant aqueous medium is a suitable system to solubilize and to promote the exhaustion of a permethrin-based mothproofing agent on wool fibres. This treatment system also confers shrink-resist properties on wool fabrics.     

30—INTERACTIONS BETWEEN ALKYLSULPHATES AND CATIONIC SHRINK-RESIST RESINS FOR WOOL PART I: THE INFLUENCE OF THE SURFACTANT CHAIN LENGTH

A kinetic study of the formation of Hercosett–alkylsulphate aggregates is reported. The stability of the turbidity that the aggregates confer to the solution was investigated as a factor of time and the concentrations of each surfactant, i.e., C_8?, C_10?, C_12?, and C_14?alkylsulphates.