Revista y Edición

Volumen 22 (2022): Edición 6 (December 2022)

Volumen 22 (2022): Edición 5 (October 2022)

Volumen 22 (2022): Edición 4 (August 2022)

Volumen 22 (2022): Edición 3 (June 2022)

Volumen 22 (2022): Edición 2 (April 2022)

Volumen 22 (2022): Edición 1 (February 2022)

Volumen 21 (2021): Edición 6 (December 2021)

Volumen 21 (2021): Edición 5 (October 2021)

Volumen 21 (2021): Edición 4 (August 2021)

Volumen 21 (2021): Edición 3 (June 2021)

Volumen 21 (2021): Edición 2 (April 2021)

Volumen 21 (2021): Edición 1 (February 2021)

Volumen 20 (2020): Edición 5 (October 2020)

Volumen 20 (2020): Edición 4 (August 2020)

Volumen 20 (2020): Edición 3 (June 2020)

Volumen 20 (2020): Edición 2 (April 2020)

Volumen 20 (2020): Edición 1 (February 2020)

Volumen 19 (2019): Edición 6 (December 2019)

Volumen 19 (2019): Edición 5 (October 2019)

Volumen 19 (2019): Edición 4 (August 2019)

Volumen 19 (2019): Edición 3 (June 2019)

Volumen 19 (2019): Edición 2 (April 2019)

Volumen 19 (2019): Edición 1 (February 2019)

Volumen 18 (2018): Edición 6 (October 2018)

Volumen 18 (2018): Edición 5 (October 2018)

Volumen 18 (2018): Edición 4 (August 2018)

Volumen 18 (2018): Edición 3 (June 2018)

Volumen 18 (2018): Edición 2 (April 2018)

Volumen 18 (2018): Edición 1 (February 2018)

Volumen 17 (2017): Edición 6 (December 2017)

Volumen 17 (2017): Edición 5 (October 2017)

Volumen 17 (2017): Edición 3 (June 2017)

Volumen 17 (2017): Edición 2 (April 2017)

Volumen 17 (2017): Edición 1 (February 2017)

Volumen 16 (2016): Edición 6 (December 2016)

Volumen 16 (2016): Edición 5 (October 2016)

Volumen 16 (2016): Edición 4 (August 2016)

Volumen 16 (2016): Edición 3 (June 2016)

Volumen 16 (2016): Edición 2 (April 2016)

Volumen 16 (2016): Edición 1 (February 2016)

Volumen 15 (2015): Edición 6 (December 2015)

Volumen 15 (2015): Edición 5 (October 2015)

Volumen 15 (2015): Edición 4 (August 2015)

Volumen 15 (2015): Edición 3 (June 2015)

Volumen 15 (2015): Edición 2 (April 2015)

Volumen 15 (2015): Edición 1 (February 2015)

Volumen 14 (2014): Edición 6 (December 2014)

Volumen 14 (2014): Edición 5 (October 2014)

Volumen 14 (2014): Edición 4 (August 2014)

Volumen 14 (2014): Edición 3 (June 2014)

Volumen 14 (2014): Edición 2 (April 2014)

Volumen 14 (2014): Edición 1 (February 2014)

Volumen 13 (2013): Edición 6 (December 2013)

Volumen 13 (2013): Edición 5 (October 2013)

Volumen 13 (2013): Edición 4 (August 2013)

Volumen 13 (2013): Edición 3 (June 2013)

Volumen 13 (2013): Edición 2 (April 2013)

Volumen 13 (2013): Edición 1 (February 2013)

Volumen 12 (2012): Edición 6 (December 2012)

Volumen 12 (2012): Edición 5 (October 2012)

Volumen 12 (2012): Edición 4 (August 2012)

Volumen 12 (2012): Edición 3 (June 2012)

Volumen 12 (2012): Edición 2 (April 2012)

Volumen 12 (2012): Edición 1 (February 2012)

Volumen 11 (2011): Edición 6 (December 2011)

Volumen 11 (2011): Edición 5 (October 2011)

Volumen 11 (2011): Edición 4 (August 2011)

Volumen 11 (2011): Edición 3 (June 2011)

Volumen 11 (2011): Edición 2 (April 2011)

Volumen 11 (2011): Edición 1 (February 2011)

Volumen 10 (2010): Edición 6 (December 2010)

Volumen 10 (2010): Edición 5 (October 2010)

Volumen 10 (2010): Edición 4 (August 2010)

Volumen 10 (2010): Edición 3 (June 2010)

Volumen 10 (2010): Edición 2 (April 2010)

Volumen 10 (2010): Edición 1 (February 2010)

Volumen 9 (2009): Edición 6 (December 2009)

Volumen 9 (2009): Edición 5 (October 2009)

Volumen 9 (2009): Edición 4 (August 2009)

Volumen 9 (2009): Edición 3 (June 2009)

Volumen 9 (2009): Edición 2 (April 2009)

Volumen 9 (2009): Edición 1 (February 2009)

Volumen 8 (2008): Edición 6 (December 2008)

Volumen 8 (2008): Edición 5 (October 2008)

Volumen 8 (2008): Edición 4 (August 2008)

Volumen 8 (2008): Edición 3 (June 2008)

Volumen 8 (2008): Edición 2 (April 2008)

Volumen 8 (2008): Edición 1 (February 2008)

Detalles de la revista
Formato
Revista
eISSN
1335-8871
Publicado por primera vez
07 Mar 2008
Periodo de publicación
6 veces al año
Idiomas
Inglés

Buscar

Volumen 18 (2018): Edición 3 (June 2018)

Detalles de la revista
Formato
Revista
eISSN
1335-8871
Publicado por primera vez
07 Mar 2008
Periodo de publicación
6 veces al año
Idiomas
Inglés

Buscar

6 Artículos
Acceso abierto

Proportional Error Back-Propagation (PEB): Real-Time Automatic Loop Closure Correction for Maintaining Global Consistency in 3D Reconstruction with Minimal Computational Cost

Publicado en línea: 12 Jun 2018
Páginas: 86 - 93

Resumen

Abstract

This paper introduces a robust, real-time loop closure correction technique for achieving global consistency in 3D reconstruction, whose underlying notion is to back-propagate the cumulative transformation error appearing while merging the pairs of consecutive frames in a sequence of shots taken by an RGB-D or depth camera. The proposed algorithm assumes that the starting frame and the last frame of the sequence roughly overlap. In order to verify the robustness and reliability of the proposed method, namely, Proportional Error Back- Propagation (PEB), it has been applied to numerous case-studies, which encompass a wide range of experimental conditions, including different scanning trajectories with reversely directed motions within them, and the results are presented. The main contribution of the proposed algorithm is its considerably low computational cost which has the possibility of usage in real-time 3D reconstruction applications. Also, neither manual input nor interference is required from the user, which renders the whole process automatic.

Palabras clave

  • 3D reconstruction
  • global consistency
  • loop closure correction
  • Iterative Closest Point
  • Proportional Error Back-propagation
Acceso abierto

Self-Organizing Map Classification of the Extremely Low-Frequency Magnetic Field Produced by Typical Tablet Computers

Publicado en línea: 12 Jun 2018
Páginas: 94 - 99

Resumen

Abstract

In this paper, the extremely low frequency magnetic field produced by the tablet computers is explored. The measurement of the tablet computers’ magnetic field is performed by using a measuring geometry previously proposed for the laptop computers. The experiment is conducted on five Android tablet computers. The measured values of the magnetic field are compared to the widely accepted TCO safety standard. Then, the results are classified by the Self-Organizing Map method in order to create different levels of safety or danger concerning the magnetic field to which tablet computer users are exposed. Furthermore, a brief comparison of the obtained magnetic field levels with the ones from typical laptops is performed. At the end, a practical suggestion on how to avoid the high exposure to the low frequency magnetic field emitted by the tablet computers is given.

Palabras clave

  • Classification
  • magnetic field
  • measurement
  • Self-organizingmap
  • tablet computers
Acceso abierto

Development of a Device to Measure Mass and Resuspension Rate of Dust inside Confined Environments

Publicado en línea: 12 Jun 2018
Páginas: 100 - 106

Resumen

Abstract

A dust explosion is one of the key security issues for many industrial, pharmaceutical and agro-alimentary plants and for the safety of the workers. We have developed an optoelectronic sensor system to determine the mass of deposited dust and the resuspension rate. The authors also mount antennas on an optoelectronic sensor system to perform measurements remotely. The technique used is based on a non-invasive light absorption method. The paper reports a cost analysis in order to demonstrate the possibility to use, in our optoelectronic sensor system, several sensors to monitor large volume. In this paper the authors present the sensor system, the test and calibration of its components together with the results and the error analysis, demonstrating experimentally what is the maximum and the minimum readable range.

Palabras clave

  • Measure
  • sensor
  • mass
  • resuspension rate
  • non-invasive
Acceso abierto

Design and Construction of Novel Instrumentation for Low-Field MR Tomography

Publicado en línea: 12 Jun 2018
Páginas: 107 - 112

Resumen

Abstract

Magnetic resonance imaging (MRI) is a very popular tool for diagnostic applications and research studies. Low-field MR scanners, usually with an open design, are suitable for claustrophobic and obese patients, as well as for children, who may be fearful in closed MR scanners. However, these types of scanners provide lower spatial resolution and a lower signal-to-noise ratio (SNR) if compared with the same examination performed at the same time at high field scanners. It is dominantly caused by the low field strength and other factors, such as radiofrequency noise. Therefore, a long measurement time is usually necessary. This research paper is focused on the development of novel probes and preamplifiers for low-field MR scanners to improve SNR, and thus, shorten the measurement time. In this study, we describe the design of a high impedance preamplifier and a high temperature superconductor (HTS) coil. This novel instrumentation was compared with uncooled and cooled copper coils. Improvement in SNR in the case of an HTS coil is reported.

Palabras clave

  • Imaging
  • MRI
  • low-field tomography
  • signal-to-noise ratio (SNR)
  • probe
  • coils
  • preamplifiers
Acceso abierto

Dimensional and Geometrical Errors in Vacuum Thermoforming Products: An Approach to Modeling and Optimization by Multiple Response Optimization

Publicado en línea: 12 Jun 2018
Páginas: 113 - 122

Resumen

Abstract

In the vacuum thermoforming process, the product deviations depend on several parameters of the system, which make the analysis, the computational modeling, and the optimization of errors a multi-variable process with conflicting objectives. In this sense, the aim of this work was to study the dimensional and geometrical errors as well as the optimization (minimization) of these errors in one typical vacuum thermoforming product made of polystyrene (PS). In particular, it was intended to predict and minimize errors in a range of ideal tolerances using Multiple Response Optimization (MRO) Models. Thus, through the fractional factorial design (2k-p), initial experimental tests were performed using proposed measurement procedures, and Analysis of Variance being the data analysis is discussed. Following that, the MRO models were implemented which were also validated to represent the sample data. Through this analysis of the results, it can be concluded that the regression models of errors are not linear functions, hence, the developed models are valid for the studied process, and finally that the validation results proved the efficiency of MOR models developed, but these models will not be able to generalize to new situations in a range far from the values studied.

Palabras clave

  • Dimensional and geometrical errors
  • vacuum thermoforming process
  • multiple response optimization
  • plastics processing
Acceso abierto

Experimental Models and Correlations between Surface Parameters after Slide Diamond Burnishing

Publicado en línea: 12 Jun 2018
Páginas: 123 - 129

Resumen

Abstract

In the paper the set of representative parameters for a comprehensive assessment of the surface texture status after slide burnishing has been proposed. The analysis of correlations between the parameters of the surface texture, obtained by slide diamond burnishing of 317Ti steel has been performed. Correlations have been determined and several groups of surface texture parameters with strong mutual correlations (also parameters uncorrelated with the other) have been selected. For both groups of parameters - representative and uncorrelated - experimental mathematical relations defining influences of the input parameters of slide diamond burnishing on the surface texture parameters have been developed. Also, interaction effects for individual parameters of this finishing process have been disclosed. It has been found that by appropriate selection of input conditions of the slide diamond burnishing process, it is possible to obtain a wide range of states of the surface texture.

Palabras clave

  • Surface texture
  • finishing
  • slide diamond burnishing
  • 317Ti
6 Artículos
Acceso abierto

Proportional Error Back-Propagation (PEB): Real-Time Automatic Loop Closure Correction for Maintaining Global Consistency in 3D Reconstruction with Minimal Computational Cost

Publicado en línea: 12 Jun 2018
Páginas: 86 - 93

Resumen

Abstract

This paper introduces a robust, real-time loop closure correction technique for achieving global consistency in 3D reconstruction, whose underlying notion is to back-propagate the cumulative transformation error appearing while merging the pairs of consecutive frames in a sequence of shots taken by an RGB-D or depth camera. The proposed algorithm assumes that the starting frame and the last frame of the sequence roughly overlap. In order to verify the robustness and reliability of the proposed method, namely, Proportional Error Back- Propagation (PEB), it has been applied to numerous case-studies, which encompass a wide range of experimental conditions, including different scanning trajectories with reversely directed motions within them, and the results are presented. The main contribution of the proposed algorithm is its considerably low computational cost which has the possibility of usage in real-time 3D reconstruction applications. Also, neither manual input nor interference is required from the user, which renders the whole process automatic.

Palabras clave

  • 3D reconstruction
  • global consistency
  • loop closure correction
  • Iterative Closest Point
  • Proportional Error Back-propagation
Acceso abierto

Self-Organizing Map Classification of the Extremely Low-Frequency Magnetic Field Produced by Typical Tablet Computers

Publicado en línea: 12 Jun 2018
Páginas: 94 - 99

Resumen

Abstract

In this paper, the extremely low frequency magnetic field produced by the tablet computers is explored. The measurement of the tablet computers’ magnetic field is performed by using a measuring geometry previously proposed for the laptop computers. The experiment is conducted on five Android tablet computers. The measured values of the magnetic field are compared to the widely accepted TCO safety standard. Then, the results are classified by the Self-Organizing Map method in order to create different levels of safety or danger concerning the magnetic field to which tablet computer users are exposed. Furthermore, a brief comparison of the obtained magnetic field levels with the ones from typical laptops is performed. At the end, a practical suggestion on how to avoid the high exposure to the low frequency magnetic field emitted by the tablet computers is given.

Palabras clave

  • Classification
  • magnetic field
  • measurement
  • Self-organizingmap
  • tablet computers
Acceso abierto

Development of a Device to Measure Mass and Resuspension Rate of Dust inside Confined Environments

Publicado en línea: 12 Jun 2018
Páginas: 100 - 106

Resumen

Abstract

A dust explosion is one of the key security issues for many industrial, pharmaceutical and agro-alimentary plants and for the safety of the workers. We have developed an optoelectronic sensor system to determine the mass of deposited dust and the resuspension rate. The authors also mount antennas on an optoelectronic sensor system to perform measurements remotely. The technique used is based on a non-invasive light absorption method. The paper reports a cost analysis in order to demonstrate the possibility to use, in our optoelectronic sensor system, several sensors to monitor large volume. In this paper the authors present the sensor system, the test and calibration of its components together with the results and the error analysis, demonstrating experimentally what is the maximum and the minimum readable range.

Palabras clave

  • Measure
  • sensor
  • mass
  • resuspension rate
  • non-invasive
Acceso abierto

Design and Construction of Novel Instrumentation for Low-Field MR Tomography

Publicado en línea: 12 Jun 2018
Páginas: 107 - 112

Resumen

Abstract

Magnetic resonance imaging (MRI) is a very popular tool for diagnostic applications and research studies. Low-field MR scanners, usually with an open design, are suitable for claustrophobic and obese patients, as well as for children, who may be fearful in closed MR scanners. However, these types of scanners provide lower spatial resolution and a lower signal-to-noise ratio (SNR) if compared with the same examination performed at the same time at high field scanners. It is dominantly caused by the low field strength and other factors, such as radiofrequency noise. Therefore, a long measurement time is usually necessary. This research paper is focused on the development of novel probes and preamplifiers for low-field MR scanners to improve SNR, and thus, shorten the measurement time. In this study, we describe the design of a high impedance preamplifier and a high temperature superconductor (HTS) coil. This novel instrumentation was compared with uncooled and cooled copper coils. Improvement in SNR in the case of an HTS coil is reported.

Palabras clave

  • Imaging
  • MRI
  • low-field tomography
  • signal-to-noise ratio (SNR)
  • probe
  • coils
  • preamplifiers
Acceso abierto

Dimensional and Geometrical Errors in Vacuum Thermoforming Products: An Approach to Modeling and Optimization by Multiple Response Optimization

Publicado en línea: 12 Jun 2018
Páginas: 113 - 122

Resumen

Abstract

In the vacuum thermoforming process, the product deviations depend on several parameters of the system, which make the analysis, the computational modeling, and the optimization of errors a multi-variable process with conflicting objectives. In this sense, the aim of this work was to study the dimensional and geometrical errors as well as the optimization (minimization) of these errors in one typical vacuum thermoforming product made of polystyrene (PS). In particular, it was intended to predict and minimize errors in a range of ideal tolerances using Multiple Response Optimization (MRO) Models. Thus, through the fractional factorial design (2k-p), initial experimental tests were performed using proposed measurement procedures, and Analysis of Variance being the data analysis is discussed. Following that, the MRO models were implemented which were also validated to represent the sample data. Through this analysis of the results, it can be concluded that the regression models of errors are not linear functions, hence, the developed models are valid for the studied process, and finally that the validation results proved the efficiency of MOR models developed, but these models will not be able to generalize to new situations in a range far from the values studied.

Palabras clave

  • Dimensional and geometrical errors
  • vacuum thermoforming process
  • multiple response optimization
  • plastics processing
Acceso abierto

Experimental Models and Correlations between Surface Parameters after Slide Diamond Burnishing

Publicado en línea: 12 Jun 2018
Páginas: 123 - 129

Resumen

Abstract

In the paper the set of representative parameters for a comprehensive assessment of the surface texture status after slide burnishing has been proposed. The analysis of correlations between the parameters of the surface texture, obtained by slide diamond burnishing of 317Ti steel has been performed. Correlations have been determined and several groups of surface texture parameters with strong mutual correlations (also parameters uncorrelated with the other) have been selected. For both groups of parameters - representative and uncorrelated - experimental mathematical relations defining influences of the input parameters of slide diamond burnishing on the surface texture parameters have been developed. Also, interaction effects for individual parameters of this finishing process have been disclosed. It has been found that by appropriate selection of input conditions of the slide diamond burnishing process, it is possible to obtain a wide range of states of the surface texture.

Palabras clave

  • Surface texture
  • finishing
  • slide diamond burnishing
  • 317Ti

Planifique su conferencia remota con Sciendo