Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/1142
2024-03-29T02:37:14Z
2024-03-29T02:37:14Z
Characterization of time domain EM field double-loaded curved loop probe
Pous Solà, Marc
Quílez Figuerola, Marcos
Fernández Chimeno, Mireya
Silva Martínez, Fernando
http://hdl.handle.net/2117/366175
2022-12-11T08:41:05Z
2022-04-21T12:17:59Z
Characterization of time domain EM field double-loaded curved loop probe
Pous Solà, Marc; Quílez Figuerola, Marcos; Fernández Chimeno, Mireya; Silva Martínez, Fernando
In this paper, we present and analyze the performance of a double-loaded curved loop probe to measure simultaneously electric and magnetic fields (EMF). The aim is to construct a probe that can be fitted to non-planar structures and have a proper response to EMF. The curved probe is studied in comparison with well-known planar probes, which have been verified and used previously. The time-domain data obtained through EM simulation allow us to identify if the probe's response is suitable although its geometry. Finally, the probe has been constructed and evaluated with experimental test, measuring and validating the conclusions find out by the EM simulation.
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2022-04-21T12:17:59Z
Pous Solà, Marc
Quílez Figuerola, Marcos
Fernández Chimeno, Mireya
Silva Martínez, Fernando
In this paper, we present and analyze the performance of a double-loaded curved loop probe to measure simultaneously electric and magnetic fields (EMF). The aim is to construct a probe that can be fitted to non-planar structures and have a proper response to EMF. The curved probe is studied in comparison with well-known planar probes, which have been verified and used previously. The time-domain data obtained through EM simulation allow us to identify if the probe's response is suitable although its geometry. Finally, the probe has been constructed and evaluated with experimental test, measuring and validating the conclusions find out by the EM simulation.
Sedimentation monitoring of the active biomass in bioreactors by electrical impedance spectroscopy
Cerrillo Moreno, Míriam
Serrano Finetti, Roberto Ernesto
Mata Calabuig, Nuria
http://hdl.handle.net/2117/342669
2022-03-01T01:37:01Z
2021-03-29T09:37:31Z
Sedimentation monitoring of the active biomass in bioreactors by electrical impedance spectroscopy
Cerrillo Moreno, Míriam; Serrano Finetti, Roberto Ernesto; Mata Calabuig, Nuria
Sequencing batch reactors are used in wastewater treatment to produce biogas (methane). Currently, when biogas production ceases the active sludge sedimentation process is not monitored but operated on a fixed time basis. One step towards gas production optimization would be to detect sedimentation and no expend time unnecessarily. In this work the use of electrical impedance spectroscopy is explored as a tool for
sedimentation monitoring. Two electrodes were placed vertically on the reactor wall and the impedance measurements were used to compute the impedance estimator E2. Changes in E2 have proven to be reliable enough to detect whenever the active sludge fell below the lower electrode position hence enabling the development of impedance probes to monitor sedimentation for this kind of reactors.
2021-03-29T09:37:31Z
Cerrillo Moreno, Míriam
Serrano Finetti, Roberto Ernesto
Mata Calabuig, Nuria
Sequencing batch reactors are used in wastewater treatment to produce biogas (methane). Currently, when biogas production ceases the active sludge sedimentation process is not monitored but operated on a fixed time basis. One step towards gas production optimization would be to detect sedimentation and no expend time unnecessarily. In this work the use of electrical impedance spectroscopy is explored as a tool for
sedimentation monitoring. Two electrodes were placed vertically on the reactor wall and the impedance measurements were used to compute the impedance estimator E2. Changes in E2 have proven to be reliable enough to detect whenever the active sludge fell below the lower electrode position hence enabling the development of impedance probes to monitor sedimentation for this kind of reactors.
On a finite domain magnetic localization by means of TMR triaxial sensors
Cerro, G
Ferrigno, L
Laracca, M
Milano, F.
Bellitti, Paolo
Serpelloni, Mauro
Casas Piedrafita, Óscar
http://hdl.handle.net/2117/342137
2021-03-22T12:20:31Z
2021-03-22T12:16:32Z
On a finite domain magnetic localization by means of TMR triaxial sensors
Cerro, G; Ferrigno, L; Laracca, M; Milano, F.; Bellitti, Paolo; Serpelloni, Mauro; Casas Piedrafita, Óscar
The paper proposes the realization and the preliminary characterization of a short–range localization systems based on the measurement of magnetic fields. Fixed anchors that generate sinusoidal wave magnetic fields at different frequencies and mobile anchors that measure the received magnetic field values compose the system. Main topics faced in the paper are: the realization and the preliminary characterization of threedimensional magnetic field sensors based on the suitable arrangement of single axis TMR magnetic sensors and the proposal of a novel, scalable and flexible localization set-up allowing multiple mobile agents without increasing the complexity and the operational time of the system. Thanks to the low cost and the flexibility of the proposal, the realized system has a wide impact on the possible applications in industrial, medical and smart-life fields. For example, it can be adopted in localization of probes that execute the defect detection in specimen, in the realization of low cost devices that help in recognizing the health–state of peoples affected by motor problems related to neurological diseases, in application related to the virtual reality, etc. At this stage, the obtained results place the measurement accuracy lower than 1 cm when the localization range is a cube of 30 cm.
2021-03-22T12:16:32Z
Cerro, G
Ferrigno, L
Laracca, M
Milano, F.
Bellitti, Paolo
Serpelloni, Mauro
Casas Piedrafita, Óscar
The paper proposes the realization and the preliminary characterization of a short–range localization systems based on the measurement of magnetic fields. Fixed anchors that generate sinusoidal wave magnetic fields at different frequencies and mobile anchors that measure the received magnetic field values compose the system. Main topics faced in the paper are: the realization and the preliminary characterization of threedimensional magnetic field sensors based on the suitable arrangement of single axis TMR magnetic sensors and the proposal of a novel, scalable and flexible localization set-up allowing multiple mobile agents without increasing the complexity and the operational time of the system. Thanks to the low cost and the flexibility of the proposal, the realized system has a wide impact on the possible applications in industrial, medical and smart-life fields. For example, it can be adopted in localization of probes that execute the defect detection in specimen, in the realization of low cost devices that help in recognizing the health–state of peoples affected by motor problems related to neurological diseases, in application related to the virtual reality, etc. At this stage, the obtained results place the measurement accuracy lower than 1 cm when the localization range is a cube of 30 cm.
Electromagnetic characterization of 3D printed antennas employing conductive filament
Pous Solà, Marc
Azpúrua Auyanet, Marco Aurelio
Quílez Figuerola, Marcos
Mateu Mateus, Marc
Fernández Chimeno, Mireya
Silva Martínez, Fernando
http://hdl.handle.net/2117/336858
2022-12-11T04:28:49Z
2021-02-04T08:52:07Z
Electromagnetic characterization of 3D printed antennas employing conductive filament
Pous Solà, Marc; Azpúrua Auyanet, Marco Aurelio; Quílez Figuerola, Marcos; Mateu Mateus, Marc; Fernández Chimeno, Mireya; Silva Martínez, Fernando
This work presents the need to accurately define EM characterization of novel materials like the 3D conductive filament. Although these construction techniques and materials are currently used by the industry, the influence of the manufacturing process is still not properly characterized. In this paper, different monopoles are assembled modifying the 3D printing structure when a conductive filament is employed to fabricate the radiating element. Measurements of the S 11 parameter are combined with electromagnetic simulations to determine the different performances of the built antennas. The results highlight that the definition of the printing parameters has a strong influence on the conductivity of the resulting 3D printed monopoles, producing remarkable variations at the antenna performance. Modifying the results from monopoles not suitable to propagate to performances that can produce proper electromagnetic fields.
2021-02-04T08:52:07Z
Pous Solà, Marc
Azpúrua Auyanet, Marco Aurelio
Quílez Figuerola, Marcos
Mateu Mateus, Marc
Fernández Chimeno, Mireya
Silva Martínez, Fernando
This work presents the need to accurately define EM characterization of novel materials like the 3D conductive filament. Although these construction techniques and materials are currently used by the industry, the influence of the manufacturing process is still not properly characterized. In this paper, different monopoles are assembled modifying the 3D printing structure when a conductive filament is employed to fabricate the radiating element. Measurements of the S 11 parameter are combined with electromagnetic simulations to determine the different performances of the built antennas. The results highlight that the definition of the printing parameters has a strong influence on the conductivity of the resulting 3D printed monopoles, producing remarkable variations at the antenna performance. Modifying the results from monopoles not suitable to propagate to performances that can produce proper electromagnetic fields.
Accelerating K-mer Frequency Counting with GPU and Non-Volatile Memory
Cadenelli, Nicola
Polo Cantero, José
Carrera Pérez, David
http://hdl.handle.net/2117/127558
2022-05-17T11:09:51Z
2019-01-24T15:30:16Z
Accelerating K-mer Frequency Counting with GPU and Non-Volatile Memory
Cadenelli, Nicola; Polo Cantero, José; Carrera Pérez, David
The emergence of Next Generation Sequencing (NGS) platforms has increased the throughput of genomic sequencing and in turn the amount of data that needs to be processed, requiring highly efficient computation for its analysis. In this context, modern architectures including accelerators and non-volatile memory are essential to enable the mass exploitation of these bioinformatics workloads. This paper presents a redesign of the main component of a state-of-the-art reference-free method for variant calling, SMUFIN, which has been adapted to make the most of GPUs and NVM devices. SMUFIN relies on counting the frequency of k-mers (substrings of length k) in DNA sequences, which also constitutes a well-known problem for many bioinformatics workloads, such as genome assembly. We propose techniques to improve the efficiency of k-mer counting and to scale-up workloads like SMUFIN that used to require 16 nodes of Marenostrum 3 to a single machine with a GPU and NVM drives. Results show that although the single machine is not able to improve the time to solution of 16 nodes, its CPU time is 7.5x shorter than the aggregate CPU time of the 16 nodes, with a reduction in energy consumption of 5.5x. © 2017 IEEE.
2019-01-24T15:30:16Z
Cadenelli, Nicola
Polo Cantero, José
Carrera Pérez, David
The emergence of Next Generation Sequencing (NGS) platforms has increased the throughput of genomic sequencing and in turn the amount of data that needs to be processed, requiring highly efficient computation for its analysis. In this context, modern architectures including accelerators and non-volatile memory are essential to enable the mass exploitation of these bioinformatics workloads. This paper presents a redesign of the main component of a state-of-the-art reference-free method for variant calling, SMUFIN, which has been adapted to make the most of GPUs and NVM devices. SMUFIN relies on counting the frequency of k-mers (substrings of length k) in DNA sequences, which also constitutes a well-known problem for many bioinformatics workloads, such as genome assembly. We propose techniques to improve the efficiency of k-mer counting and to scale-up workloads like SMUFIN that used to require 16 nodes of Marenostrum 3 to a single machine with a GPU and NVM drives. Results show that although the single machine is not able to improve the time to solution of 16 nodes, its CPU time is 7.5x shorter than the aggregate CPU time of the 16 nodes, with a reduction in energy consumption of 5.5x. © 2017 IEEE.
Performance characterization of spark workloads on shared NUMA Systems
Baig, Shuja-ur-Rehman
Amaral, Marcelo
Polo Cantero, José
Carrera Pérez, David
http://hdl.handle.net/2117/123195
2022-05-17T12:27:07Z
2018-10-29T19:15:26Z
Performance characterization of spark workloads on shared NUMA Systems
Baig, Shuja-ur-Rehman; Amaral, Marcelo; Polo Cantero, José; Carrera Pérez, David
As the adoption of Big Data technologies becomes the norm in an increasing number of scenarios, there is also a growing need to optimize them for modern processors. Spark has gained momentum over the last few years among companies looking for high performance solutions that can scale out across different cluster sizes. At the same time, modern processors can be connected to large amounts of physical memory, in the range of up to few terabytes. This opens an enormous range of opportunities for runtimes and applications that aim to improve their performance by leveraging low latencies and high bandwidth provided by RAM. The result is that there are several examples today of applications that have started pushing the in-memory computing paradigm to accelerate tasks. To deliver such a large physical memory capacity, hardware vendors have leveraged Non-Uniform Memory Architectures (NUMA). This paper explores how Spark-based workloads are impacted by the effects of NUMA-placement decisions, how different Spark configurations result in changes in delivered performance, how the characteristics of the applications can be used to predict workload collocation conflicts, and how to improve performance by collocating workloads in scale-up nodes. We explore several workloads run on top of the IBM Power8 processor, and provide manual strategies that can leverage performance improvements up to 40% on Spark workloads when using smart processor-pinning and workload collocation strategies.
2018-10-29T19:15:26Z
Baig, Shuja-ur-Rehman
Amaral, Marcelo
Polo Cantero, José
Carrera Pérez, David
As the adoption of Big Data technologies becomes the norm in an increasing number of scenarios, there is also a growing need to optimize them for modern processors. Spark has gained momentum over the last few years among companies looking for high performance solutions that can scale out across different cluster sizes. At the same time, modern processors can be connected to large amounts of physical memory, in the range of up to few terabytes. This opens an enormous range of opportunities for runtimes and applications that aim to improve their performance by leveraging low latencies and high bandwidth provided by RAM. The result is that there are several examples today of applications that have started pushing the in-memory computing paradigm to accelerate tasks. To deliver such a large physical memory capacity, hardware vendors have leveraged Non-Uniform Memory Architectures (NUMA). This paper explores how Spark-based workloads are impacted by the effects of NUMA-placement decisions, how different Spark configurations result in changes in delivered performance, how the characteristics of the applications can be used to predict workload collocation conflicts, and how to improve performance by collocating workloads in scale-up nodes. We explore several workloads run on top of the IBM Power8 processor, and provide manual strategies that can leverage performance improvements up to 40% on Spark workloads when using smart processor-pinning and workload collocation strategies.
Battery aging impedance spectroscopy and incremental capacity analysis
Ovejas Benedicto, Victòria Júlia
Cuadras Tomàs, Àngel
http://hdl.handle.net/2117/116956
2022-09-18T06:34:51Z
2018-05-06T09:38:23Z
Battery aging impedance spectroscopy and incremental capacity analysis
Ovejas Benedicto, Victòria Júlia; Cuadras Tomàs, Àngel
We analize electrochemical LiFePO4 cells with impedance spectroscopy and incremental capacity analysis in order to establish a correlation with capacity fade. We found that polarization and diffusion impeances increased with aging, but at different rates depending on the aging stage. This aging stage dependence was also found in ICA analyzes, where the lithium intercalation was investigated. A correlation with capacity decrease measured with Coulomb counting was established.
2018-05-06T09:38:23Z
Ovejas Benedicto, Victòria Júlia
Cuadras Tomàs, Àngel
We analize electrochemical LiFePO4 cells with impedance spectroscopy and incremental capacity analysis in order to establish a correlation with capacity fade. We found that polarization and diffusion impeances increased with aging, but at different rates depending on the aging stage. This aging stage dependence was also found in ICA analyzes, where the lithium intercalation was investigated. A correlation with capacity decrease measured with Coulomb counting was established.
Battery Impedance Spectroscopy obtained from Electrochemical Model
Miró Jané, Pol
Cuadras Tomàs, Àngel
http://hdl.handle.net/2117/116870
2020-07-23T23:08:37Z
2018-05-02T10:42:48Z
Battery Impedance Spectroscopy obtained from Electrochemical Model
Miró Jané, Pol; Cuadras Tomàs, Àngel
We investigate impedance spectra obtained from an electrochemical model using pulsed signals. We characterize the dependence of NiMH battery parameters such as electrodes porosity and conductivity on impedance. We are able to relate impedance to simulated battery aging. Impedance as a function of state of charge is also investigated. Further characterization on accuracy and resolution and results on temperature dependence will be submitted.
2018-05-02T10:42:48Z
Miró Jané, Pol
Cuadras Tomàs, Àngel
We investigate impedance spectra obtained from an electrochemical model using pulsed signals. We characterize the dependence of NiMH battery parameters such as electrodes porosity and conductivity on impedance. We are able to relate impedance to simulated battery aging. Impedance as a function of state of charge is also investigated. Further characterization on accuracy and resolution and results on temperature dependence will be submitted.
A novel algorithm for fast BCG cycle extraction in ambulatory scenarios
Gómez Clapers, Joan
Casanella Alonso, Ramón
Pallàs-Areny, Ramon
http://hdl.handle.net/2117/102905
2022-10-09T01:40:47Z
2017-03-27T10:48:25Z
A novel algorithm for fast BCG cycle extraction in ambulatory scenarios
Gómez Clapers, Joan; Casanella Alonso, Ramón; Pallàs-Areny, Ramon
A novel algorithm JDet for ballistocardiogram (BCG) cycle extraction is presented that is intended for the fast generation of ensemble averages in ambulatory scenarios where the ECG signal is not available. First, the sensitivity (Se) and positive predictivity (+P) of JDet are evaluated on recordings obtained from 14 healthy subjects that stood on a modified weighing scale, and the results are compared with those from BSeg++, a popular BCG cycle-extraction algorithm. Second, the signal-to-noise ratio (SNR) is calculated for ensemble averages generated by using JDet, BSeg++, and the ECG R-waves on recordings of different duration. The results show that JDet has higher Se and similar +P than BSeg++. Therefore, the quality of the ensemble averages generated from JDet can be comparable to those generated from the ECG, the only cost being a 25% longer recording time.
2017-03-27T10:48:25Z
Gómez Clapers, Joan
Casanella Alonso, Ramón
Pallàs-Areny, Ramon
A novel algorithm JDet for ballistocardiogram (BCG) cycle extraction is presented that is intended for the fast generation of ensemble averages in ambulatory scenarios where the ECG signal is not available. First, the sensitivity (Se) and positive predictivity (+P) of JDet are evaluated on recordings obtained from 14 healthy subjects that stood on a modified weighing scale, and the results are compared with those from BSeg++, a popular BCG cycle-extraction algorithm. Second, the signal-to-noise ratio (SNR) is calculated for ensemble averages generated by using JDet, BSeg++, and the ECG R-waves on recordings of different duration. The results show that JDet has higher Se and similar +P than BSeg++. Therefore, the quality of the ensemble averages generated from JDet can be comparable to those generated from the ECG, the only cost being a 25% longer recording time.
Impact of the mechanical interface on BCG signals obtained from electronic weighing scales
Casanella Alonso, Ramón
Gómez Clapers, Joan
Hernández Urrea, Marc
Pallàs-Areny, Ramon
http://hdl.handle.net/2117/102902
2023-04-02T00:34:17Z
2017-03-27T09:55:42Z
Impact of the mechanical interface on BCG signals obtained from electronic weighing scales
Casanella Alonso, Ramón; Gómez Clapers, Joan; Hernández Urrea, Marc; Pallàs-Areny, Ramon
This work analyzes the reproducibility of the BCG obtained from different weighing scales. First, the natural frequency of three commercial bathroom scales has been characterized by an impulse excitation test. Second, the BCG and the ECG from 5 healthy subjects (27 ± 4 years) have been recorded for 60 s by sequentially standing on these weighing scales connected to the same analog front-end and signal acquisition system. An ensemble average representative of each subject and weighing scale has been obtained by applying Woody’s method with the ECG as a timing reference. Consecutive BCG signals obtained from the three scales show consistent systematic intra-subject differences in the timing of the J peak that can reach up to 30 ms. This timing error is relevant because it is about 50 % of the changes induced by typical respiratory maneuvers, such as Valsalva’s, used to modulate hemodynamic parameters in correlation studies between changes in J timing with respect to different cardiac fiducial points. Due to its ubiquity, weighing scales are promising devices for monitoring cardiovascular function at home but their frequency response must be accounted for and minimal performance standards should be defined for them.
2017-03-27T09:55:42Z
Casanella Alonso, Ramón
Gómez Clapers, Joan
Hernández Urrea, Marc
Pallàs-Areny, Ramon
This work analyzes the reproducibility of the BCG obtained from different weighing scales. First, the natural frequency of three commercial bathroom scales has been characterized by an impulse excitation test. Second, the BCG and the ECG from 5 healthy subjects (27 ± 4 years) have been recorded for 60 s by sequentially standing on these weighing scales connected to the same analog front-end and signal acquisition system. An ensemble average representative of each subject and weighing scale has been obtained by applying Woody’s method with the ECG as a timing reference. Consecutive BCG signals obtained from the three scales show consistent systematic intra-subject differences in the timing of the J peak that can reach up to 30 ms. This timing error is relevant because it is about 50 % of the changes induced by typical respiratory maneuvers, such as Valsalva’s, used to modulate hemodynamic parameters in correlation studies between changes in J timing with respect to different cardiac fiducial points. Due to its ubiquity, weighing scales are promising devices for monitoring cardiovascular function at home but their frequency response must be accounted for and minimal performance standards should be defined for them.