Pub Date : 2017-07-24DOI: 10.1109/EESMS.2017.8052688
Sakib Abdullah, Sandor Bertalan, S. Masar, Adem Coskun, I. Kale
Wildfires, often dubbed megafires, have in recent times increased in both frequency and scale, owing largely to human error as well as climate change. Due to their uncontrolled unpredictable rapid growth and behaviour, they can quickly become difficult to contain, leading to significant loss of lives, wildlife and property. It is therefore critical to tackle such fires in the early stages. This demands a reduction in the initial time to detection while ensuring reliability and a low false alarm rate. This paper discusses a new category of compact, easily deployable and energy efficient approach to sensor nodes for the continued monitoring of forest environments as well as the early detection of fires in their infancy based on a combination of sensory inputs. The sensor network reported in this paper was tested with other subsystems/technologies, in a real-life firefighting trial as part of a coordinated firefighting scenario with promising results.
{"title":"A wireless sensor network for early forest fire detection and monitoring as a decision factor in the context of a complex integrated emergency response system","authors":"Sakib Abdullah, Sandor Bertalan, S. Masar, Adem Coskun, I. Kale","doi":"10.1109/EESMS.2017.8052688","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052688","url":null,"abstract":"Wildfires, often dubbed megafires, have in recent times increased in both frequency and scale, owing largely to human error as well as climate change. Due to their uncontrolled unpredictable rapid growth and behaviour, they can quickly become difficult to contain, leading to significant loss of lives, wildlife and property. It is therefore critical to tackle such fires in the early stages. This demands a reduction in the initial time to detection while ensuring reliability and a low false alarm rate. This paper discusses a new category of compact, easily deployable and energy efficient approach to sensor nodes for the continued monitoring of forest environments as well as the early detection of fires in their infancy based on a combination of sensory inputs. The sensor network reported in this paper was tested with other subsystems/technologies, in a real-life firefighting trial as part of a coordinated firefighting scenario with promising results.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"37 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133234999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-24DOI: 10.1109/EESMS.2017.8052691
M. Rossi, Pietro Tosato
A lot of research and studies have shown the impact of pollution on health, and a lot of regulation are in action in the European Union and other countries around the world defining the allowed concentration levels of volatile chemicals. Standard measurements equipment are very expensive, and static large stations require space and high power consumption, thus are not suitable to realize portable equipment nor to seamlessly be integrated in Smart Cities. In this paper we present the design and evaluation of a portable pollution monitoring equipment as small as 20×15×5 cm, powered by mini PV arrays, embedding particulate matter and CO/VOCs sensors for air quality estimation. A LoRa radio transceiver completes the set of peripherals. Finally, energy budget analysis shows that neutral operations can be achieved enabling a “deploy and forget” paradigm suitable for the IoT.
{"title":"Energy neutral design of an IoT system for pollution monitoring","authors":"M. Rossi, Pietro Tosato","doi":"10.1109/EESMS.2017.8052691","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052691","url":null,"abstract":"A lot of research and studies have shown the impact of pollution on health, and a lot of regulation are in action in the European Union and other countries around the world defining the allowed concentration levels of volatile chemicals. Standard measurements equipment are very expensive, and static large stations require space and high power consumption, thus are not suitable to realize portable equipment nor to seamlessly be integrated in Smart Cities. In this paper we present the design and evaluation of a portable pollution monitoring equipment as small as 20×15×5 cm, powered by mini PV arrays, embedding particulate matter and CO/VOCs sensors for air quality estimation. A LoRa radio transceiver completes the set of peripherals. Finally, energy budget analysis shows that neutral operations can be achieved enabling a “deploy and forget” paradigm suitable for the IoT.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130229619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052685
M. Carminati, V. Stefanelli, G. Ferrari, M. Sampietro, A. Turolla, M. Rossi, S. Malavasi, M. Antonelli, V. Pifferi, L. Falciola
This work presents the first prototype of the Smart Pipe, a compact and intelligent wireless node hosting miniaturized sensors, embedded in a flange, for distributed and real-time monitoring of water contamination and for optimization of water treatment plants. Beyond pH and temperature, it features a low-cost and high-resolution (13 ppm, 11 ms response time) custom-designed 4-channel conductivity measurement circuit. Long-term operation and optimized on-demand maintenance are achieved by the innovative combination of an impedance sensor measuring the thickness of sludge and biofilm depositing on microelectrodes with self-cleaning capabilities offered by UV photo-regeneration of nanometric TiO2 electrodes coatings. Finally, here we also demonstrate self-powering of the unit by means of an energy harvesting control valve, regulating the flow in the water distribution network where an efficient installation of these sensors is today foreseeable.
{"title":"Smart pipe: A miniaturized sensor platform for real-time monitoring of drinking water quality","authors":"M. Carminati, V. Stefanelli, G. Ferrari, M. Sampietro, A. Turolla, M. Rossi, S. Malavasi, M. Antonelli, V. Pifferi, L. Falciola","doi":"10.1109/EESMS.2017.8052685","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052685","url":null,"abstract":"This work presents the first prototype of the Smart Pipe, a compact and intelligent wireless node hosting miniaturized sensors, embedded in a flange, for distributed and real-time monitoring of water contamination and for optimization of water treatment plants. Beyond pH and temperature, it features a low-cost and high-resolution (13 ppm, 11 ms response time) custom-designed 4-channel conductivity measurement circuit. Long-term operation and optimized on-demand maintenance are achieved by the innovative combination of an impedance sensor measuring the thickness of sludge and biofilm depositing on microelectrodes with self-cleaning capabilities offered by UV photo-regeneration of nanometric TiO2 electrodes coatings. Finally, here we also demonstrate self-powering of the unit by means of an energy harvesting control valve, regulating the flow in the water distribution network where an efficient installation of these sensors is today foreseeable.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126600581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052684
M. D'Aloia, A. Longo, Russo Ruggero, S. Stanisci, Davide Amendolare, M. Rizzi, Marco Vessia, Federico Lomastro
This paper presents a smart system based on Low Power Wide Area networks for a remote monitoring of technological room in unstaffed railway stations. The paper aim is the design of an efficient network scheme characterized by improved performance compared with the standard solution. Adopting an innovative smart System Control Strategy and a custom network topology, good results are reached in terms of reliability without increasing the amount of devices with respect the standard scheme.
{"title":"An innovative LPWA network scheme to increase system reliability in remote monitoring","authors":"M. D'Aloia, A. Longo, Russo Ruggero, S. Stanisci, Davide Amendolare, M. Rizzi, Marco Vessia, Federico Lomastro","doi":"10.1109/EESMS.2017.8052684","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052684","url":null,"abstract":"This paper presents a smart system based on Low Power Wide Area networks for a remote monitoring of technological room in unstaffed railway stations. The paper aim is the design of an efficient network scheme characterized by improved performance compared with the standard solution. Adopting an innovative smart System Control Strategy and a custom network topology, good results are reached in terms of reliability without increasing the amount of devices with respect the standard scheme.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"244 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126124439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052695
B. Gurkovskiy, Y. Bocharov, A. Simakov, E. Onishchenko
Based on open-air gas-discharge counter developed pedestrian portal monitor can detect much smaller amounts of alpha-radioactive nuclides than the best of the currently used stationary radiation monitors on the basis of gamma-ray scintillation detectors.
{"title":"Method for recognizing alpha and beta radioactive contamination in portal monitor using open-air gas-discharge counter","authors":"B. Gurkovskiy, Y. Bocharov, A. Simakov, E. Onishchenko","doi":"10.1109/EESMS.2017.8052695","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052695","url":null,"abstract":"Based on open-air gas-discharge counter developed pedestrian portal monitor can detect much smaller amounts of alpha-radioactive nuclides than the best of the currently used stationary radiation monitors on the basis of gamma-ray scintillation detectors.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130428473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052676
H. Medhat, F. Gunzer
Photonic crystals have attracted a great amount of research work in the last 20 years. Initially, their application possibilities concentrated on communications. In recent years, a lot of research has shown the capability of using these crystals in the form of photonic crystal micro cavities (PCM) in gas sensing applications for e.g. environmental monitoring. Since these crystals exhibit so called photonic bands, they allow only certain frequencies to propagate through the structure while blocking other frequencies. These bands depend on a variety of parameters including the refractive indices forming the crystal structure; most importantly, they show a strong response towards refractive index changes. Thus, it is possible to create gas sensors with high selectivity that even react to the small refractive index changes of different gaseous analytes. These structures are often proposed to be used as chemical sensors, since they allow for very high Q values and thus very high selectivity. The performance of such sensors can be easily simulated with help of numerical approaches such as Finite Elements Method (FEM). Previous research that aimed at studying PCM sensors typically neglected losses due to signal attenuation in such simulations. In this paper we subsequently show how the Q values and the related gas sensing performance change with the imaginary refractive index of the crystal structure.
{"title":"Performance of photonic crystal based gas sensors under the influence of losses","authors":"H. Medhat, F. Gunzer","doi":"10.1109/EESMS.2017.8052676","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052676","url":null,"abstract":"Photonic crystals have attracted a great amount of research work in the last 20 years. Initially, their application possibilities concentrated on communications. In recent years, a lot of research has shown the capability of using these crystals in the form of photonic crystal micro cavities (PCM) in gas sensing applications for e.g. environmental monitoring. Since these crystals exhibit so called photonic bands, they allow only certain frequencies to propagate through the structure while blocking other frequencies. These bands depend on a variety of parameters including the refractive indices forming the crystal structure; most importantly, they show a strong response towards refractive index changes. Thus, it is possible to create gas sensors with high selectivity that even react to the small refractive index changes of different gaseous analytes. These structures are often proposed to be used as chemical sensors, since they allow for very high Q values and thus very high selectivity. The performance of such sensors can be easily simulated with help of numerical approaches such as Finite Elements Method (FEM). Previous research that aimed at studying PCM sensors typically neglected losses due to signal attenuation in such simulations. In this paper we subsequently show how the Q values and the related gas sensing performance change with the imaginary refractive index of the crystal structure.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132464162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052683
V. Di Lecce, D. Petruzzelli, C. Guaragnella, A. Cardellicchio, Giuseppe Dentamaro, Alessandro Quarto, D. Soldo, R. Dario
This paper is focused on preliminary results of the research project “Monitoraggio continuo per le Acque reflue Urbane ed Industriali per l'ecoindustria” (MAUI). Special attention is paid on methods for real-time wastewater monitoring. It is known that field-sampling operations condition significantly data reliability from both qualitative and quantitative aspects. A vapour phase e-nose (namely VPeN) based on a semiconductor sensor array was used to get real time monitoring. The device does not require consumables and may be easily connected to data acquisition networks.
本文重点介绍了MAUI研究项目“持续监测(Monitoraggio continuo per le acquque refue Urbane Industriali per l’ecoindustria)”的初步结果。对污水实时监测的方法给予了特别的关注。众所周知，实地抽样作业在定性和定量方面对数据可靠性都有很大的影响。采用基于半导体传感器阵列的气相电子鼻(VPeN)进行实时监测。该设备不需要消耗品，并且可以很容易地连接到数据采集网络。
{"title":"Real-time monitoring system for urban wastewater","authors":"V. Di Lecce, D. Petruzzelli, C. Guaragnella, A. Cardellicchio, Giuseppe Dentamaro, Alessandro Quarto, D. Soldo, R. Dario","doi":"10.1109/EESMS.2017.8052683","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052683","url":null,"abstract":"This paper is focused on preliminary results of the research project “Monitoraggio continuo per le Acque reflue Urbane ed Industriali per l'ecoindustria” (MAUI). Special attention is paid on methods for real-time wastewater monitoring. It is known that field-sampling operations condition significantly data reliability from both qualitative and quantitative aspects. A vapour phase e-nose (namely VPeN) based on a semiconductor sensor array was used to get real time monitoring. The device does not require consumables and may be easily connected to data acquisition networks.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134444420","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052689
R. Garello, V. Kerbaol
Oil pollution on the ocean has been highlighted in the past 40 years by several tanker accidents in Europe, like those of Exxon Valdez, Erika or Prestige. But these oil tanker accidents only account for a few percent of the total oil pollution worldwide and hide the regular pollution in important traffic zones like the Mediterranean and other oceans caused by oil drillings or illegal discharges. Due to very regular acquisitions from imaging radar on board satellites since the beginning of the 90's, statistical information about slicks is available all over the world oceans. From the first SAR satellites dedicated to research (ERS series, RadarSat-1) via European Envisat, TerraSAR-X, Cosmo Skymed or Canadian RadarSat-2 to the new European Sentinel series (namely Sentinel 1A, 1B and possibly 1C in the future) oriented towards services and applications, the expertise from the R&D community allows a much better oil spill monitoring nowadays. Oil spills appear as a dark patch on the SAR image. Nevertheless, detecting oil slicks and oil spills remains difficult, as other phenomena are also modifying the sea surface conditions: wind, sea state, currents, … In order to go beyond oil spill detection and tracking and for setting an efficient prevention system, one must also detect and identify the ships responsible of the oil discharges. For that purpose, synergetic approaches have been used, mixing the radar imaging inputs with met information and mandatory ship identification systems (AIS — Automatic Identification System) mainly. This effort is quite important as the vast majority of these pollutions occur near the coastal zones where 80% of the world population lives.
{"title":"Oil pollution monitoring: An integrated approach","authors":"R. Garello, V. Kerbaol","doi":"10.1109/EESMS.2017.8052689","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052689","url":null,"abstract":"Oil pollution on the ocean has been highlighted in the past 40 years by several tanker accidents in Europe, like those of Exxon Valdez, Erika or Prestige. But these oil tanker accidents only account for a few percent of the total oil pollution worldwide and hide the regular pollution in important traffic zones like the Mediterranean and other oceans caused by oil drillings or illegal discharges. Due to very regular acquisitions from imaging radar on board satellites since the beginning of the 90's, statistical information about slicks is available all over the world oceans. From the first SAR satellites dedicated to research (ERS series, RadarSat-1) via European Envisat, TerraSAR-X, Cosmo Skymed or Canadian RadarSat-2 to the new European Sentinel series (namely Sentinel 1A, 1B and possibly 1C in the future) oriented towards services and applications, the expertise from the R&D community allows a much better oil spill monitoring nowadays. Oil spills appear as a dark patch on the SAR image. Nevertheless, detecting oil slicks and oil spills remains difficult, as other phenomena are also modifying the sea surface conditions: wind, sea state, currents, … In order to go beyond oil spill detection and tracking and for setting an efficient prevention system, one must also detect and identify the ships responsible of the oil discharges. For that purpose, synergetic approaches have been used, mixing the radar imaging inputs with met information and mandatory ship identification systems (AIS — Automatic Identification System) mainly. This effort is quite important as the vast majority of these pollutions occur near the coastal zones where 80% of the world population lives.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"116 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134549155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052699
M. Diaferio, A. Fraddosio, Mario Daniele Piccioni, Anna Castellano, L. Mangialardi, L. Soria
Operational Modal Analysis (OMA) is extensively used as a tool for the modal identification and the Structural Health Monitoring (SHM) of civil constructions. However, the classical experimental techniques based on the use of accelerometers involve high costs and long times for performing the measurements, and often interrupting the service of the construction is also needed. In this paper, with reference to the specific case study of the identification of modal parameters of a typical span of a railway viaduct, we analyze the capability and the possible improvements of the ground based radar interferometric experimental set-up. This analysis is aimed at developing a fast, inexpensive and practical procedure for the periodic monitoring of the viaduct.
{"title":"Some issues in the structural health monitoring of a railway viaduct by ground based radar interferometry","authors":"M. Diaferio, A. Fraddosio, Mario Daniele Piccioni, Anna Castellano, L. Mangialardi, L. Soria","doi":"10.1109/EESMS.2017.8052699","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052699","url":null,"abstract":"Operational Modal Analysis (OMA) is extensively used as a tool for the modal identification and the Structural Health Monitoring (SHM) of civil constructions. However, the classical experimental techniques based on the use of accelerometers involve high costs and long times for performing the measurements, and often interrupting the service of the construction is also needed. In this paper, with reference to the specific case study of the identification of modal parameters of a typical span of a railway viaduct, we analyze the capability and the possible improvements of the ground based radar interferometric experimental set-up. This analysis is aimed at developing a fast, inexpensive and practical procedure for the periodic monitoring of the viaduct.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"44 11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133489814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2017-07-01DOI: 10.1109/EESMS.2017.8052690
Angelo Garofalo, N. Testoni, A. Marzani, L. De Marchi
Impact damage may compromise the structural integrity and resistance. When an impact occurs, it is important to check if a structural damage was originated at the impact location. On thin structures, impacts generate guided stress waves (Lamb waves) which can be analyzed to infer the actual impact position. A novel strategy to determine the Lamb wave direction of arrival, generated by an impact occurring in thin plate structures, is proposed in this paper. As already known, the wave mode propagation of GWs (i.e. Lamb Waves) along thin structures is characterized by a dispersive behaviour which could hinder an accurate estimation of the wave direction of arrival when monitoring the DToA associated to different sensors. Evidently, this is to be avoid in SHM (Structural Healt Monitoring) techniques. Overcoming this limitation is the aim of the paper, therefor a new estimation technique in the wavelet domain has been carried out for passive sensors. The proposed procedure, based on the CWT decomposition of non-linear signals acquired by three closely-located piezoelectrics transducers, causes a resampling of the time-frequency plane allowing to separate the wave components travelling at different velocities as well as to highlight the frequency dependence of the DToA. The multiresolution analysis has the advantage that the DToA among two different transducers can be computed multiple times, at different frequencies range, by applying the cross-correlation method in the CWT domain for each computed scale. In this way, the GW direction of arrival can be estimated making an averaging procedure across scales to the arc-tangent of the ratio between the DToA among specific sensors. The optimization of the transducers disposition on the plate has been also carried out and, in the end, experimental results are shown.
{"title":"Multiresolution wavelet analysis to estimate Lamb waves direction of arrival in passive monitoring techniques","authors":"Angelo Garofalo, N. Testoni, A. Marzani, L. De Marchi","doi":"10.1109/EESMS.2017.8052690","DOIUrl":"https://doi.org/10.1109/EESMS.2017.8052690","url":null,"abstract":"Impact damage may compromise the structural integrity and resistance. When an impact occurs, it is important to check if a structural damage was originated at the impact location. On thin structures, impacts generate guided stress waves (Lamb waves) which can be analyzed to infer the actual impact position. A novel strategy to determine the Lamb wave direction of arrival, generated by an impact occurring in thin plate structures, is proposed in this paper. As already known, the wave mode propagation of GWs (i.e. Lamb Waves) along thin structures is characterized by a dispersive behaviour which could hinder an accurate estimation of the wave direction of arrival when monitoring the DToA associated to different sensors. Evidently, this is to be avoid in SHM (Structural Healt Monitoring) techniques. Overcoming this limitation is the aim of the paper, therefor a new estimation technique in the wavelet domain has been carried out for passive sensors. The proposed procedure, based on the CWT decomposition of non-linear signals acquired by three closely-located piezoelectrics transducers, causes a resampling of the time-frequency plane allowing to separate the wave components travelling at different velocities as well as to highlight the frequency dependence of the DToA. The multiresolution analysis has the advantage that the DToA among two different transducers can be computed multiple times, at different frequencies range, by applying the cross-correlation method in the CWT domain for each computed scale. In this way, the GW direction of arrival can be estimated making an averaging procedure across scales to the arc-tangent of the ratio between the DToA among specific sensors. The optimization of the transducers disposition on the plate has been also carried out and, in the end, experimental results are shown.","PeriodicalId":285890,"journal":{"name":"2017 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS)","volume":"67 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121094046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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