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Machado, Renato
Alternative names
Publications (10 of 10) Show all publications
Molin, R., Fabrin, A., Sperotto, P., Alves, D., Bayer, F., Machado, R., . . . Ulander, L. (2016). Iterative Change Detection Algorithm for Low-Frequency UWB SAR. In: : . Paper presented at XXXIV Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2016), Santarém, Brazil (pp. 654-658).
Open this publication in new window or tab >>Iterative Change Detection Algorithm for Low-Frequency UWB SAR
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2016 (English)Conference paper, Published paper (Refereed)
National Category
Signal Processing Remote Sensing Other Engineering and Technologies not elsewhere specified
Identifiers
urn:nbn:se:bth-13875 (URN)
Conference
XXXIV Simpósio Brasileiro de Telecomunicações e Processamento de Sinais (SBrT 2016), Santarém, Brazil
Available from: 2017-02-03 Created: 2017-02-03 Last updated: 2017-02-24Bibliographically approved
Renato, M., Vu, V. T., Pettersson, M., Dammert, P. & Hellsten, H. (2016). The stability of UWB low-frequency SAR images. IEEE Geoscience and Remote Sensing Letters, 13(8), 1114-1118
Open this publication in new window or tab >>The stability of UWB low-frequency SAR images
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2016 (English)In: IEEE Geoscience and Remote Sensing Letters, ISSN 1545-598X, E-ISSN 1558-0571, Vol. 13, no 8, p. 1114-1118Article in journal (Refereed) Published
Abstract [en]

This letter presents an analysis of prefiltered clutter ultrawideband (UWB) very high frequency synthetic aperture radar (SAR) images. The image data are reorganized into subvectors based on the observation of the image-pair magnitude samples. Based on this approach, we present a statistical description of the SAR clutter obtained by the subtraction between two real SAR images. The statistical analysis based on bivariate distribution data organized into different intervals of magnitude can be an important tool to further understand the properties of the backscattered signal for low-frequency SAR images. In this letter, it is found that, for “good” image pairs, the subtracted image has Gaussian distributed clutter backscattering and that the noise mainly consists of the thermal noise and, therefore, speckle noise does not have to be considered. This is a consequence of the stable backscattering for a UWB low-frequency SAR system.

Place, publisher, year, edition, pages
IEEE, 2016
Keywords
Synthetic aperture radar, Histograms, Clutter, Statistical analysis, Manganese, Stability analysis, Speckle
National Category
Signal Processing
Identifiers
urn:nbn:se:bth-13844 (URN)10.1109/LGRS.2016.2569582 (DOI)000382683100016 ()
Available from: 2017-01-30 Created: 2017-01-30 Last updated: 2018-01-15Bibliographically approved
Machado, R., Pettersson, M. I., Vu, V. T., Dammert, P. & Hellsten, H. (2015). EMPIRICAL-STATISTICAL ANALYSIS OF AMPLITUDE SAR IMAGES FOR CHANGE DETECTION ALGORITHMS. In: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS): . Paper presented at IEEE International Geoscience and Remote Sensing Symposium (IGARSS), JUL 26-31, 2015, Milan, ITALY (pp. 365-368).
Open this publication in new window or tab >>EMPIRICAL-STATISTICAL ANALYSIS OF AMPLITUDE SAR IMAGES FOR CHANGE DETECTION ALGORITHMS
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2015 (English)In: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), 2015, p. 365-368Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents an analysis of pre-filtered clutter VHF SAR images. The image data are reorganized into sub-vectors based on the observation of the image-pair magnitude samples. Based on this approach, we present a statistical description of the SAR clutter obtained by the subtraction between two real SAR images. The statistical analysis based on bivariate distribution data organized into different intervals of magnitude can be an important tool to further understand the properties of the backscattered signal, which can be a valuable premise for change detection processing.

Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 2153-6996
Keywords
Low-frequency SAR; clutter distribution; CDA; statistical analysis
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Communication Systems
Identifiers
urn:nbn:se:bth-11858 (URN)000371696700094 ()978-1-4799-7929-5 (ISBN)
Conference
IEEE International Geoscience and Remote Sensing Symposium (IGARSS), JUL 26-31, 2015, Milan, ITALY
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2017-03-07Bibliographically approved
Hellisten, H., Machado, R., Pettersson, M. I., Vu, V. T. & Dammert, P. (2015). EXPERIMENTAL RESULTS ON CHANGE DETECTION BASED ON BAYES PROBABILITY THEOREM. In: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS): . Paper presented at IEEE International Geoscience and Remote Sensing Symposium (IGARSS), JUL 26-31, 2015, Milan, ITALY (pp. 318-321). IEEE Communications Society
Open this publication in new window or tab >>EXPERIMENTAL RESULTS ON CHANGE DETECTION BASED ON BAYES PROBABILITY THEOREM
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2015 (English)In: 2015 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS), IEEE Communications Society, 2015, p. 318-321Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we propose a new change detection (CD) algorithm based on the Bayes theorem and probability assignments. Differently from any kind of likelihood ratio test (LRT) algorithms, the proposed algorithm does not present target alarms, but the probability of certain image position is a target position. In other words, the proposed method leads to quantitative estimates on the probability of a target at any pixel, whereas LRT algorithms can only be used as a figure of merit for any pixel to contain a target.

Place, publisher, year, edition, pages
IEEE Communications Society, 2015
Series
IEEE International Symposium on Geoscience and Remote Sensing IGARSS, ISSN 2153-6996
Keywords
Change detection; CARABAS; Bayes Theorem; SAR
National Category
Communication Systems Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:bth-11857 (URN)000371696700082 ()978-1-4799-7929-5 (ISBN)
Conference
IEEE International Geoscience and Remote Sensing Symposium (IGARSS), JUL 26-31, 2015, Milan, ITALY
Available from: 2016-05-02 Created: 2016-05-02 Last updated: 2016-09-28Bibliographically approved
Barbosa, V., E.R., S., Machado, R., F. G., F., S. M., T. & M. V. T., H. (2015). Linear Array Design with Switched Beams for Wireless Communications Systems. International Journal of Antennas and Propagation, 2015, Article ID 278160.
Open this publication in new window or tab >>Linear Array Design with Switched Beams for Wireless Communications Systems
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2015 (English)In: International Journal of Antennas and Propagation, ISSN 1687-5869, E-ISSN 1687-5877, Vol. 2015, article id 278160Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Hindawi, 2015
Keywords
Antenna arrays, Balloons; Base stations, Directive antennas, Economic and social effects, Mobile telecommunication systems, Radio transmission, Wireless telecommunication systems
National Category
Telecommunications
Identifiers
urn:nbn:se:bth-6383 (URN)10.1155/2015/278160 (DOI)000359221300001 ()oai:bth.se:forskinfoCA3ADC592B5BC4F3C1257E370032EC0B (Local ID)oai:bth.se:forskinfoCA3ADC592B5BC4F3C1257E370032EC0B (Archive number)oai:bth.se:forskinfoCA3ADC592B5BC4F3C1257E370032EC0B (OAI)
Available from: 2015-04-30 Created: 2015-04-30 Last updated: 2017-12-04Bibliographically approved
Vu, V. T., Machado, R., Pettersson, M. I., Dammert, P. & Hellsten, H. (2015). SAR image statistics and adaptive signal processing for change detection. In: ALGORITHMS FOR SYNTHETIC APERTURE RADAR IMAGERY XXII: . Paper presented at Conference on Algorithms for Synthetic Aperture Radar Imagery XXII, APR 23, 2015, Baltimore, MD. , Article ID 947509.
Open this publication in new window or tab >>SAR image statistics and adaptive signal processing for change detection
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2015 (English)In: ALGORITHMS FOR SYNTHETIC APERTURE RADAR IMAGERY XXII, 2015, article id 947509Conference paper, Published paper (Refereed)
Abstract [en]

The paper presents investigations on SAR image statistics and adaptive signal processing for change detection. The investigations show that the amplitude distributions of SAR images with possibly detected changes, that is retrieved with a linear subtraction operator, can approximately be represented by the probability density function of the Gaussian or normal distribution. This allows emerging the idea to use the available adaptive signal processing techniques for change detection. The experiments indicate the promising change detection results obtained with an adaptive line enhancer, one of the adaptive signal processing technique. The experiments are conducted on the data collected by CARABAS, a UWB low frequency SAR system.

Series
Proceedings of SPIE, ISSN 0277-786X ; 9475
Keywords
SAR, change detection, statistics, adaptive signal processing
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Signal Processing
Identifiers
urn:nbn:se:bth-11406 (URN)10.1117/12.2176774 (DOI)000356858900005 ()978-1-62841-591-9 (ISBN)
External cooperation:
Conference
Conference on Algorithms for Synthetic Aperture Radar Imagery XXII, APR 23, 2015, Baltimore, MD
Available from: 2016-01-14 Created: 2016-01-14 Last updated: 2016-09-08Bibliographically approved
Alaves, D., Machado, R., da Costa, D. B., Legg, A. P. & Uchoa-Filho, B. F. (2014). A dynamic hybrid antenna/relay selection scheme for the multiple-access relay channel. In: 2014 11TH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATIONS SYSTEMS (ISWCS): . Paper presented at 11th International Symposium on Wireless Communications Systems (ISWCS), Barcelona (pp. 594-599). IEEE
Open this publication in new window or tab >>A dynamic hybrid antenna/relay selection scheme for the multiple-access relay channel
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2014 (English)In: 2014 11TH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATIONS SYSTEMS (ISWCS), IEEE , 2014, p. 594-599Conference paper, Published paper (Refereed)
Abstract [en]

We propose a dynamic hybrid antenna/relay selection scheme for multiple-access relay systems. The proposed scheme aims to boost the system throughput while keeping a good error performance. By using the channel state information, the destination node performs a dynamic selection between the signals provided by the multi-antenna relay, located in the inter-cell region, and the relay nodes geographically distributed over the cells. The multi-antenna relay and the single-antenna relay nodes employ the decode-remodulate-and-forward and amplify-and-forward protocols, respectively. Results reveal that the proposed scheme offers a good tradeoff between spectral efficiency and diversity gain, which is one of the main requirements for the next generation of wireless communications systems.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
DreMF, MIMO relay systems, dynamic hybrid antenna/relay selection
National Category
Computer Sciences Signal Processing Probability Theory and Statistics
Identifiers
urn:nbn:se:bth-6512 (URN)10.1109/ISWCS.2014.6933423 (DOI)000363906500115 ()978-1-4799-5863-4 (ISBN)
Conference
11th International Symposium on Wireless Communications Systems (ISWCS), Barcelona
Available from: 2014-12-02 Created: 2014-12-01 Last updated: 2018-01-11Bibliographically approved
Alves, D. I., Machado, R., Legg, A. P. & Uchoa-Filho, B. F. (2014). Cooperative multiple-access scheme with antenna selection and incremental relaying. In: 2014 INTERNATIONAL TELECOMMUNICATIONS SYMPOSIUM (ITS): . Paper presented at International Telecommunications Symposium (ITS), Sao Paolo. São Paulo: IEEE
Open this publication in new window or tab >>Cooperative multiple-access scheme with antenna selection and incremental relaying
2014 (English)In: 2014 INTERNATIONAL TELECOMMUNICATIONS SYMPOSIUM (ITS), São Paulo: IEEE , 2014Conference paper, Published paper (Refereed)
Abstract [en]

A cooperative multiple-access scheme for wireless communications systems with antenna selection and incremental relaying is proposed. The scheme aims to improve the system throughput while preserving good performance in terms of bit error rate. The system consists of N nodes which send their information to both the destination node and the multiple-antenna relay station. Based on the channel state information, the destination node decides whether or not relaying will be performed. When the relaying is performed, the decode-remodulate-and-forward protocol is used with the best antenna. Results reveal that the proposed scheme achieves a good tradeoff between throughput and bit error rate, which makes suitable to be considered for multi-user networks.

Place, publisher, year, edition, pages
São Paulo: IEEE, 2014
Keywords
multi-user networks, Cooperative communications, multiple-access scheme
National Category
Computer Sciences Signal Processing Probability Theory and Statistics
Identifiers
urn:nbn:se:bth-6511 (URN)10.1109/ITS.2014.6947984 (DOI)000348854300034 ()oai:bth.se:forskinfo17B282CF858E7CF1C1257DA100386CED (Local ID)978-1-4799-3743-1 (ISBN)oai:bth.se:forskinfo17B282CF858E7CF1C1257DA100386CED (Archive number)oai:bth.se:forskinfo17B282CF858E7CF1C1257DA100386CED (OAI)
Conference
International Telecommunications Symposium (ITS), Sao Paolo
Available from: 2014-12-02 Created: 2014-12-01 Last updated: 2018-01-11Bibliographically approved
Valduga, S. T., Alves, D. I., Machado, R., Legg, A. P. & Loiola, M. B. (2014). Low-complexity codebook-based beamforming with four transmit antennas and quantized feedback channel. In: 2014 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC): . Paper presented at Wireless Communications and Networking Conference (WCNC). Istanbul: IEEE
Open this publication in new window or tab >>Low-complexity codebook-based beamforming with four transmit antennas and quantized feedback channel
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2014 (English)In: 2014 IEEE WIRELESS COMMUNICATIONS AND NETWORKING CONFERENCE (WCNC), Istanbul: IEEE , 2014Conference paper, Published paper (Refereed)
Abstract [en]

In this paper we propose a low-complexity codebook-based beamforming with four transmit antennas and quantized feedback channel. The codebook design aggregates the effect of power allocation and phase rotation through a simple quantized transmit scheme. The codebook-based beamforming uses the feedback information in order to maximize the instantaneous signal-to-noise ratio (SNR) at the receiver. As a result, the proposed scheme presents an array gain. An SNR analysis is performed and it is used to find the optimal feedback information in the sense of maximizing the instantaneous SNR. A bit error rate (BER) analysis for a quantized feedback channel is also derived and it is used to compare to the results obtained for the proposed scheme under different levels of quantization. Simulations are performed over quasi-static flat Rayleigh fading channels for different closed-loop codebook-based schemes with four transmit antennas and unitary transmission rate. Results illustrate that the proposed scheme achieves full diversity order and outperforms other good schemes in terms of array gain.

Place, publisher, year, edition, pages
Istanbul: IEEE, 2014
Series
IEEE Wireless Communications and Networking Conference, ISSN 1525-3511
Keywords
Quantized feedback, Coodebook, MIMO
National Category
Computer Sciences Telecommunications Signal Processing
Identifiers
urn:nbn:se:bth-6514 (URN)10.1109/WCNC.2014.6952322 (DOI)000392912400211 ()oai:bth.se:forskinfoD8B51A7EA4975CB2C1257DA10036D858 (Local ID)978-1-4799-3083-8 (ISBN)oai:bth.se:forskinfoD8B51A7EA4975CB2C1257DA10036D858 (Archive number)oai:bth.se:forskinfoD8B51A7EA4975CB2C1257DA10036D858 (OAI)
Conference
Wireless Communications and Networking Conference (WCNC)
Available from: 2014-12-02 Created: 2014-12-01 Last updated: 2018-01-11Bibliographically approved
Schlosser, E. R., Farias, R. L., Heckler, M. V. T. & Machado, R. (2014). Optimization of switched-beam arrays for communication systems. In: 2014 11TH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATIONS SYSTEMS (ISWCS): . Paper presented at 11th International Symposium on Wireless Communications Systems (ISWCS), Barcelona (pp. 579-583). IEEE
Open this publication in new window or tab >>Optimization of switched-beam arrays for communication systems
2014 (English)In: 2014 11TH INTERNATIONAL SYMPOSIUM ON WIRELESS COMMUNICATIONS SYSTEMS (ISWCS), IEEE , 2014, p. 579-583Conference paper, Published paper (Refereed)
Abstract [en]

This paper presents the application of optimization methods for the synthesis of a linear array for communication systems. By means of suitably beam switching, the array should provide coverage of a given angular area in azimuth and should allow controlling the sidelobe level simultaneously. For this purpose, two optimization methods have been used to calculate the excitation coefficient for each desired beam. The synthesis technique is demonstrated for arrays composed of isotropic and microstrip elements. By comparing the results obtained for both arrays, the need of consideration of the array element pattern during the synthesis process is demonstrated.

Place, publisher, year, edition, pages
IEEE, 2014
Keywords
microstrip antennas, sidelobe level control, switched-beam arrays
National Category
Computer Sciences Media and Communications
Identifiers
urn:nbn:se:bth-6513 (URN)10.1109/ISWCS.2014.6933420 (DOI)000363906500112 ()978-1-4799-5863-4 (ISBN)
External cooperation:
Conference
11th International Symposium on Wireless Communications Systems (ISWCS), Barcelona
Note

Wireless Communications Systems (ISWCS), 2014 11th International Symposium on http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6933420

Available from: 2014-12-02 Created: 2014-12-01 Last updated: 2018-01-11Bibliographically approved
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