Academic literature on the topic 'Radar penetrante'
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Journal articles on the topic "Radar penetrante"
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Ucha, J. M., M. Botelho, G. S. Vilas Boas, L. P. Ribeiro, and P. S. Santana. "Uso do radar penetrante no solo (GPR) na investigação dos solos dos tabuleiros costeiros no litoral norte do estado da Bahia." Revista Brasileira de Ciência do Solo 26, no. 2 (June 2002): 373–80. http://dx.doi.org/10.1590/s0100-06832002000200011.
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Foram estudados nove perfis ao longo de uma toposseqüência sobre os sedimentos do Grupo Barreiras, na Fazenda Rio Negro, município de Entre Rios (BA), utilizando a prospecção eletromagnética por meio do Radar Penetrante no Solo - "Ground-penetrating radar - GPR", objetivando analisar a utilização dessa ferramenta na aquisição de informações sobre as feições que ocorrem no solo, mediante a comparação entre os radargramas obtidos e a descrição pedológica. O equipamento utilizado foi um Geophysical Survey System modelo GPR SR system-2, com antena de 80 MHz. A análise radargramétrica confirmou o aparecimento dos fragipãs e duripãs em profundidade, que ocorrem sempre acompanhados de um processo de transformação dos solos do tipo Latossolo Amarelo e Argissolo Amarelo em Espodossolo. Os padrões de reflexão mostram claramente os domínios dos solos argilosos e dos solos arenosos, com e sem a presença dos horizontes endurecidos.
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Kılıç, Alper, İsmail Babaoğlu, Ahmet Babalık, and Ahmet Arslan. "Through-Wall Radar Classification of Human Posture Using Convolutional Neural Networks." International Journal of Antennas and Propagation 2019 (March 31, 2019): 1–10. http://dx.doi.org/10.1155/2019/7541814.
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Through-wall detection and classification are highly desirable for surveillance, security, and military applications in areas that cannot be sensed using conventional measures. In the domain of these applications, a key challenge is an ability not only to sense the presence of individuals behind the wall but also to classify their actions and postures. Researchers have applied ultrawideband (UWB) radars to penetrate wall materials and make intelligent decisions about the contents of rooms and buildings. As a form of UWB radar, stepped frequency continuous wave (SFCW) radars have been preferred due to their advantages. On the other hand, the success of classification with deep learning methods in different problems is remarkable. Since the radar signals contain valuable information about the objects behind the wall, the use of deep learning techniques for classification purposes will give a different direction to the research. This paper focuses on the classification of the human posture behind the wall using through-wall radar signals and a convolutional neural network (CNN). The SFCW radar is used to collect radar signals reflected from the human target behind the wall. These signals are employed to classify the presence of the human and the human posture whether he/she is standing or sitting by using CNN. The proposed approach achieves remarkable and successful results without the need for detailed preprocessing operations and long-term data used in the traditional approaches.
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Shumeyko, A. E., and M. L. Yaskevich. "Ground penetrate radar test of a difficult nonhomogeneous stores." Environmental Protection in Oil and Gas Complex, no. 5 (2019): 42–50. http://dx.doi.org/10.33285/2411-7013-2019-5(290)-42-50.
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Xu, Qiangqiang, Jianquan Ge, and Tao Yang. "Optimal Design of Cooperative Penetration Trajectories for Multiaircraft." International Journal of Aerospace Engineering 2020 (January 25, 2020): 1–12. http://dx.doi.org/10.1155/2020/8490531.
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At present, two kinds of shortages exist in the research on cooperative combat. One is that radar detection threat (which cannot be ignored) is rarely considered. The other is that limited efforts have been made on the cooperative penetration trajectories under the conditions of long distance, vast airspace, and wide speed range. In order to offset the shortages of the research on cooperative combat, the penetration trajectory optimization method considering the influence of aircraft radar cross-section (RCS) and the cooperative penetration strategy is proposed in this study. Firstly, the RCS data are calculated by the physical optics (PO) method. The radar detection threat model is established considering the influence of the aircraft RCS. Then, a trajectory optimization framework with the dynamic model, constraint conditions, and optimal objectives is formed. Using the hp-adaptive Radau pseudospectral method, the optimal control problem for a single aircraft flight is solved. Finally, a cooperative penetration strategy is proposed to solve the cooperative penetration problem of multiaircraft. The impact time and angle constraints are given, and the virtual target point is introduced for terminal guidance. Two cases are simulated and verified. Simulation results demonstrate that the proposed method is effective. The single aircraft can effectively penetrate, and the multiaircraft can fulfill the requirement of cooperative impact time and angle under the condition of meeting the minimum threat of radar detection.
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El Hajj, Mohammad, Nicolas Baghdadi, Hassan Bazzi, and Mehrez Zribi. "Penetration Analysis of SAR Signals in the C and L Bands for Wheat, Maize, and Grasslands." Remote Sensing 11, no. 1 (December 26, 2018): 31. http://dx.doi.org/10.3390/rs11010031.
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This paper assesses the potential of Synthetic Aperture Radar (SAR) in the C and L bands to penetrate into the canopy cover of wheat, maize and grasslands. For wheat and grasslands, the sensitivity of the C and L bands to in situ surface soil moisture (SSM) was first studied according to three levels of the Normalized Difference Vegetation Index (NDVI < 0.4, 0.4 < NDVI < 0.7, and NDVI > 0.7). Next, the temporal evolution of the SAR signal in the C and L bands was analyzed according to SSM and the NDVI. For wheat and grasslands, the results showed that the L-band in HH polarization penetrates the canopy even when the canopy is well-developed (NDVI > 0.7), whereas the penetration of the C-band into the canopy is limited for an NDVI < 0.7. For an NDVI less than 0.7, the sensitivity of the radar signal to SSM is approximately 0.27 dB/vol.% for the L-band in HH polarization and approximately 0.12 dB/vol.% for the C-band (in both VV and VH polarizations). For highly developed wheat and grassland cover (NDVI > 0.7), the sensitivity of the L-band in HH polarization to SSM is approximately 0.19 dB/vol.%, whereas as the C-band is insensitive to SSM. For maize, only the temporal evolution of the C-band according to SSM and the NDVI was studied because the swath of SAR images in the L-band did not cover the maize plots. The results showed that the C-band in VV polarization is able to penetrate the maize canopy even when the canopy is well developed (NDVI > 0.7) due to high-order scattering along the soil-vegetation pathway that contains a soil contribution. According to results obtained in this paper, the L-band would penetrate a well-developed maize cover since the penetration depth of the L-band is greater than that of the C-band.
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Becker, K. F., L. Georgi, R. Kahle, S. Voges, F. Brandenburger, J. Höfer, C. Ehrhardt, et al. "Heterogeneous integration of a miniaturized W-band radar module." International Symposium on Microelectronics 2015, no. 1 (October 1, 2015): 000766–70. http://dx.doi.org/10.4071/isom-2015-thp11.
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For radar applications, the W-band frequency range (75 – 110 GHz) is a good candidate for high-resolution distance measurement and remote detection of small or hidden objects in distances of 10 cm to ≫ 20 m. As electromagnetic waves in this frequency range can easily penetrate rough atmosphere like fog, smoke or dust, W-band radars are perfectly suited for automotive, aviation, industrial and security applications. Additional benefit is that atmosphere has an absorption minimum at 94 GHz, so relative small output power is sufficient to achieve long range coverage. By combining and enhancing knowledge from the disciplines of heterogeneous integration technology and compound semiconductor-technology, the Fraunhofer Institutes IAF, IPA and IZM developed a miniaturized and low cost 94 GHz radar module. Result of this approach is a highly miniaturized radar module built using a modular approach. The radar components are mounted on a dedicated RF-NF-hybrid PCB while the signal processing is done on a separate board stacked below. This hybrid RF-module is combined with highly integrated digital processing PCB via micro connectors in a way that the radar system and an adapted conical HDPE-lens fit into an aluminum housing of 42×80×27 mm3 with a weight of only 160 grams for the whole module. The paper will describe the technological basis for such a frequency modulated continuous wave [FMCW] W-band radar module and describe in detail the technological features that enabled the assembly of such a miniaturized but high-performance system. The module yields an evaluated distance measurement accuracy of 5 ppm (5 μm deviation per meter target distance) while its low weight and small dimensions pave the way for a variety of new applications, including mobile operation.
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Hargrave, Chad, Lance Munday, Gareth Kennedy, and André de Kock. "Mine Machine Radar Sensor for Emergency Escape." Resources 9, no. 2 (February 4, 2020): 16. http://dx.doi.org/10.3390/resources9020016.
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This paper presents the results of recent work to develop and trial a mine machine radar sensor for underground coal mine vehicles. There is an urgent industry need for an integrated solution to the problem of operating an underground vehicle in conditions of dense ambient dust and/or smoke, such as may occur in underground coal mines after a fire or explosion. Under these conditions, sensors such as cameras and lidar offer limited assistance due to their inability to penetrate thick dust. Thermal infrared can penetrate dust but still results in poor vision, as there is insufficient temperature contrast between the tunnel walls and the ambient air. Microwave radar sensors are able to penetrate the dust, and suitable radar sensors have been developed for use in the automation industry. Adapting such sensors for use in an underground coal mining environment was the focus of this research effort, and involved trialing a suitable sensor in dust and smoke chambers as well as trials in an underground coal mine with introduced dust. Data processing and the development of a suitable user interface were key aspects of the research. Since any sensor would have to operate in an explosive atmosphere, a related research work developed a flameproof dielectric enclosure to allow the use of the radar in the mine environment.
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Jofre, L., A. Broquetas, J. Romeu, S. Blanch, A. P. Toda, X. Fabregas, and A. Cardama. "UWB Tomographic Radar Imaging of Penetrable and Impenetrable Objects." Proceedings of the IEEE 97, no. 2 (February 2009): 451–64. http://dx.doi.org/10.1109/jproc.2008.2008854.
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Hu, Xiaoyu, Jinming Ge, Jiajing Du, Qinghao Li, Jianping Huang, and Qiang Fu. "A robust low-level cloud and clutter discrimination method for ground-based millimeter-wavelength cloud radar." Atmospheric Measurement Techniques 14, no. 2 (March 3, 2021): 1743–59. http://dx.doi.org/10.5194/amt-14-1743-2021.
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Abstract. Low-level clouds play a key role in the energy budget and hydrological cycle of the climate system. The accurate long-term observation of low-level clouds is essential for understanding their climate effect and model constraints. Both ground-based and spaceborne millimeter-wavelength cloud radars can penetrate clouds but the detected low-level clouds are always contaminated by clutter, which needs to be removed. In this study, we develop an algorithm to accurately separate low-level clouds from clutter for ground-based cloud radar using multi-dimensional probability distribution functions along with the Bayesian method. The radar reflectivity, linear depolarization ratio, spectral width, and their dependence on the time of the day, height, and season are used as the discriminants. A low-pass spatial filter is applied to the Bayesian undecided classification mask by considering the spatial correlation difference between clouds and clutter. The final feature mask result has a good agreement with lidar detection, showing a high probability of detection rate (98.45 %) and a low false alarm rate (0.37 %). This algorithm will be used to reliably detect low-level clouds at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) site for the study of their climate effect and the interaction with local abundant dust aerosol in semi-arid regions.
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Nag, S., and L. Peters. "Radar images of penetrable targets generated from ramp profile functions." IEEE Transactions on Antennas and Propagation 49, no. 1 (2001): 32–40. http://dx.doi.org/10.1109/8.910526.
Full textDissertations / Theses on the topic "Radar penetrante"
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Oliveira, J?nior Josibel Gomes de. "Dois testes de imageamento com GPR em problemas de controle ambiental em regi?es tropicais: migra??o de dunas e localiza??o de dutos de ?leo enterrados." Universidade Federal do Rio Grande do Norte, 2001. http://repositorio.ufrn.br:8080/jspui/handle/123456789/18778.
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Previous issue date: 2001-02-21Because the penetration depth of Ground Penetrating Radar (GPR) signals is very limited in high conductive soils, the usefullness of this method in tropical regions is not yet completly known. The main objective of this researh is to test the usefullness of the method in Brazil. Two typical problems where GPR has been used in Europe and North American were choosed for this test: the first one is to characterize the internal structures of a sand body and the second problem is the localization of old buried pipes lines. The first test was done near the city of S?o Bento do Norte, in the northern coast of Rio Grande do Norte state, NE Brazil. In this region, there is a sand dune that is migrating very fast in the direction of adjacent settling areas. To characterize the internal structure of the dune and its relationship to the prevailing wind direction, as a preliminary step to understand the dune migration, GPR profiles using the 400 MHz frequency were performed in E-W, N-S, NE-SW, and SE-NW directions over the sand dune intersecting at the top of the dune. The practical resolution of the GPR data is around 30 cm; this was sufficient to distinguish individual foresets inside the dune. After applying the elevation correction to the data, we identified that dips of bedding structures are smallest for the N-S profile, which is perpendicular to the dominant wind direction, largest for the E-W profile, and intermediate for the SW-NE and SE-NW profiles. Foresets in the E-W profile dip with angles varying from 2 to 6 degrees. In the E-W profile, the water table and a horizontal truncation interface separating two generations of dunes were identified, as well as an abrupt directional change in the foreset patterns associated to a lateral contact between two dune generations, the older one extending to the west. The used high frequency of 400 Mhz does not allow a penetration deep enough to map completely these internal contacts. The second test was done near Estreito, a small town near Carna?bais city, also in Rio Grande do Norte state. In this locality, there are several old pipe lines buried in area covered by plantations where digging should be minimized. Several GPR profiles using the 400 and 200 MHz frequency were performed trying to intercept perpendicularly the possible pipe lines. Because of the high conductivity of the soil, the raw original data can hardly be use to identify the pipe lines. However, after an adequate processing over the 200 MHz profiles, six pipe lines were identified. As a global result of the tests, GPR can be very usefull if the conductivity of the ground is low or, in the case of medium conductivities of the soils, if adequate processing is performed
O principal objetivo deste trabalho, ? testar o m?todo GPR (Ground Penetrating Radar) em ambientes com clima tropical. Desta forma, foram escolhidas duas localidades distintas que apresentam problemas considerados padr?es para a aplica??o do GPR. A natureza n?o invasiva deste m?todo, aliada ao baixo custo, rapidez e facilidade de opera??o, torna-o adequado para os trabalhos aqui propostos. A primeira localidade est? situada no munic?pio de S?o Bento do Norte e o problema relacionado a ela consiste na caracteriza??o de estruturas internas de dunas. Se??es de GPR com antena de 400 Mhz foram levantadas nas dire??es E-W, N-S, NE-SW e SE-NW. Estes perfis interceptaram-se no topo da duna e possibilitaram estabelecer rela??es entre a sua estrutura interna e a sua dire??o de migra??o, associada ao vento dominante na ?rea. Foi poss?vel identificar tamb?m contatos laterais entre dunas de diferentes gera??es, assim como bounding surfaces, n?vel fre?tico e mergulho de camadas. Na segunda localidade, de nome Estreito (pr?ximo ao munic?pio de Carnaubais), foram levantadas se??es de GPR com antenas de 200 Mhz e 400 Mhz para detectar dutos antigos de petr?leo enterrados em uma ?rea agricult?vel. Os perfis de GPR foram realizados perpendicularmente ? suposta dire??o dos dutos e, da sua interpreta??o, determinous-se a posi??o de seis oleodutos de diferentes di?metros (4", 10" e 16") enterrados, cujas posi??es exatas eram desconhecidas, assim como a produndidade em que estes se encontravam (variando de 1,2m e 1,5m). No tratamento dos dados foi adotado um processsamento semelhante ?queles utilizado nos m?todos s?smicos (ajuste do tempo zero, ganho, migra??o, corre??o topogr?fica, dewow, deconvolu??o e filtros passa-banda). Este processamento permitiu estabelecer rela??es entre os refletores contidos nas se??es de GPR e estruturas geol?gicas (ou n?o) presentes nos ambientes. A corre??o topogr?fica possibilitou identificar com precis?o estruturas planas (como o n?vel fre?tico), ao passo que a migra??o dos dados proporcionou a exata posi??o dos dutos
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Thunberg, Billy, and Kalle Kurttio. "Radardetektering av stålämnen med hjälp av UWB-radar." Thesis, Högskolan i Gävle, Elektronik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-22538.
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Stålindustrierna Sandvik, Sandviken och SSAB, Borlänge tillverkar billets (kvadratiska ochlångsmala stålämnen). Vid tillverkningen av billets förflyttas stålämnena stegvis i ugnensamtidigt som de hettas upp. När stålämnena når slutet av ugnen lyfts de ur av en externmaskin. För att tids- och energieffektivisera den sista etappen krävs positionsbestämning avämnena då de når slutet av ugnen. Dessa aspekter är viktiga ur en ekonomisk såväl sommiljövänlig synpunkt då induktiva ugnar använder en stor mängd energi. Tillämpningen ärtänkt att användas av stålindustrin. UWB-radarns bredbandiga karakteristisk gör den till en lämplig ersättare till dagens sensorersom kräver håltagning i ugnens valv. Det breda frekvensspektrat hos en UWB-radarmöjliggör ytmonterade enheter i kontrast till de konventionella sensorer som används idag.Underhållsstopp för rengöring av sensorhålen kan då undvikas. Arbetet började med teoretisk studie rörande UWB-teknik och radar i allmänhet. Därefterutformades testscenarion för att studera radarvågen under varierande förhållanden. Denradaruppställning som användes under testscenariorna var framåtspridande radar. Deresulterande mätningarna signalbehandlades i Matlab. Resultatet visar att det är möjligt att detektera objekt av olika dimensioner och former på olikaavstånd, med hjälp av UWB-radar. Denna metod fungerar även som ett passagelarm, vilkenkan användas inom fler områden.The steel industries Sandvik, Sandviken and SSAB, Borlänge, produces billets (quadratic,long steel units). Billets travelling through the furnace will heat up. At the end of the furnace,the billets will require precision measurements regarding its position, due to the extractingdevice. Sensors that are used today require an unobstructed view, which is achieved by holesin the furnace walls. Maintenance is needed in order to ensure that no impurities are cloggingthe holes. The goal with this thesis is to investigate whether it is possible to detect rectangular billets byusing an UWB-radar system. The broadband characteristics of an UWB-unit makes it asuitable successor, as free sight is not a requirement. This will decrease downtown due tomaintenance and optimize the time required for billets extraction.This involves economic and environmental aspects as well, due to lower energy consumption. This will be tested by collecting radar measurements for further signal processing. The usedradar system is forward scattering radar. The work started with a theoretical study aboutUWB-technique and basics about radar. Thereafter test scenarios were designed to study howthe radar wave is affected by changing environments. The resulting measurements were latersignal processed in Matlab. This work shows that it is possible to detect billets with various dimensions, using UWBradar.The algorithm can also be used as a passage alarm, which can be used in other areasthan furnaces.
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PAPI, FEDERICO. "Sviluppo di un Prototipo Radar Penetrante SF-CW ad Altissima Risoluzione." Doctoral thesis, 2016. http://hdl.handle.net/2158/1025123.
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Wang, Wen-Yu, and 王文郁. "Signal classification of Ground Penetrate Radar using neural network analyses." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/n2jgm5.
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碩士朝陽科技大學
營建工程系碩士班
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The investigation of underground pipelines is very important prior the excavation project. Such investigation is usually based on the official record in the highway department. Accidents and sometimes disputes over the destruction of underground pipelines arise often due to false or incomplete information in the official record. Ground penetration radar, or GPR, may be very helpful to investigate underground pipelines. The objective of current study is to improve the detection of underground pipelines based on the GPR signals. Sample signals are obtained in the laboratory tests with a mockup of flexible pavement and a tube. The depth and type of the tube is varied. The collected signals are analyzed using artificial neural networks. The trained neural networks are then applied to GPR signals from the field tests. The initial results are promising.
Book chapters on the topic "Radar penetrante"
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Liang, Hongyu, Wenbin Xu, Xiaoli Ding, Lei Zhang, and Songbo Wu. "Urban Sensing with Spaceborne Interferometric Synthetic Aperture Radar." In Urban Informatics, 345–65. Singapore: Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-15-8983-6_21.
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AbstractSynthetic aperture radar (SAR) and interferometric SAR (InSAR) are state-of-the-art radar remote sensing technologies and are very useful for urban remote sensing. The technologies have some very special characteristics compared to optical remote sensing and are especially advantageous in cloudy regions due to the ability of the microwave radar signals used by the current SAR sensors to penetrate clouds. This chapter introduces the basic concepts of SAR, differential InSAR, and multi-temporal InSAR, and their typical applications in urban remote sensing. Examples of applying the various InSAR techniques in generating DEMs and monitoring ground and infrastructure deformation are given. The capabilities and limitations of InSAR techniques in urban remote sensing are briefly discussed.
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S., Kannadhasan, Kanagaraj Venusamy, and Nagarajan R. "Recent Trends in Internet of Medical Things." In Advances in Medical Technologies and Clinical Practice, 39–47. IGI Global, 2022. http://dx.doi.org/10.4018/978-1-6684-5741-2.ch003.
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Ultrashort pulses with exceptionally broad bandwidth and low power are transmitted and received by ultrawideband radar systems. While these features make UWB radars safe for use around people and compatible with other equipment, they also make it more difficult to detect the echo signal they produce. As a result, the radar antenna is crucial in UWB systems; in fact, it must be able to meet the broad band of frequency response and directivity requirements simultaneously. It is suggested that a radiated beam or gadgets worn on the body be used to minimize “losses” to the surroundings. In UWB imaging devices, a very narrow pulse is broadcast from a UWB antenna to penetrate the body. When the pulse travels through several tissues, reflections and scattering take place at the interfaces. Special attention should be paid to the diffused signal from a tumor-initiating small-tissue sample.
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DuLong, Jessica. "“It was like breathing dirt.”." In Saved at the Seawall, 71–85. Cornell University Press, 2021. http://dx.doi.org/10.7591/cornell/9781501759123.003.0005.
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This chapter discusses how, in the instant the South Tower collapsed, the scale of the disaster had magnified, transforming the evacuation-in-progress into a full-blown rescue effort. The cloud rolling past the seawall blanketed the river's surface and blinded boat captains, forcing them to navigate by radar alone. But sometimes even the radar could not penetrate the particle-filled air. Nevertheless, ferry crews did not stop rescuing people: approximately 200 injured would end up transported aboard New York Waterway ferries by day's end. Despite the unprecedented scale of this disaster, mariners' “jack of all trades” capabilities proved essential in the aftermath of the attacks. Although the specific prerequisites have changed over time, attaining a Coast Guard “ticket” requires merchant mariners to complete training and earn certifications in first aid, CPR, and shipboard firefighting, among other specialized areas. On that morning, all that training was put to the test.
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Smith, Anne M. "Active Microwave Systems for Monitoring Drought Stress." In Monitoring and Predicting Agricultural Drought. Oxford University Press, 2005. http://dx.doi.org/10.1093/oso/9780195162349.003.0015.
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Remote sensing can provide timely and economical monitoring of large areas. It provides the ability to generate information on a variety of spatial and temporal scales. Generally, remote sensing is divided into passive and active depending on the sensor system. The majority of remote-sensing studies concerned with drought monitoring have involved visible–infrared sensor systems, which are passive and depend on the sun’s illumination. Radar (radio detection and ranging) is an active sensor system that transmits energy in the microwave region of the electromagnetic spectrum and measures the energy reflected back from the landscape target. The energy reflected back is called backscatter. The attraction of radar over visible– infrared remote sensing (chapters 5 and 6) is its independence from the sun, enabling day/night operations, as well as its ability to penetrate cloud and obtain data under most weather conditions. Thus, unlike visible–infrared sensors, radar offers the opportunity to acquire uninterrupted information relevant to drought such as soil moisture and vegetation stress. Drought conditions manifest in multiple and complex ways. Accordingly, a large number of drought indices have been defined to signal abnormally dry conditions and their effects on crop growth, river flow, groundwater, and so on (Tate and Gustard, 2000). In the field of radar remote sensing, much work has been devoted to developing algorithms to retrieve geophysical parameters such as soil moisture, crop biomass, and vegetation water content. In principle, these parameters would be highly relevant for monitoring agricultural drought. However, despite the existence of a number of radar satellite systems, progress in the use of radar in environmental monitoring, particularly in respect to agriculture, has been slower than anticipated. This may be attributed to the complex nature of radar interactions with agricultural targets and the suboptimal configuration of the satellite sensors available in the 1990s (Ulaby, 1998; Bouman et al., 1999). Because most attention is still devoted to the problem of deriving high-quality soil moisture and vegetation products, there have been few investigations on how to combine such radar products with other data and models to obtain value-added agricultural drought products.
Conference papers on the topic "Radar penetrante"
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Sainath, Kamalesh, Fernando L. Teixeira, and Scott Hensley. "Interferometric SAR coherence arising from the vertically-polarized electromagnetic interrogation of layered, penetrable dielectric media." In 2015 European Radar Conference (EuRAD). IEEE, 2015. http://dx.doi.org/10.1109/eurad.2015.7346223.
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Linlin Lei, Sixin Liu, Lei Fu, Xu Meng, and Junjun Wu. "Examples of pre-stack reverse-time migration applied to ground penetrate radar synthetic data." In 15th International Conference on Ground-Penetrating Radar (GPR) 2014. IEEE, 2014. http://dx.doi.org/10.1109/icgpr.2014.6970501.
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Sang-Wook Kim, Jong-Sung Choi, and Se-Yun Kim. "Distortion of pulse signatures penetrated obliquely through tunnel in a cross-borehole pulse radar." In 2012 14th International Conference on Ground Penetrating Radar (GPR). IEEE, 2012. http://dx.doi.org/10.1109/icgpr.2012.6254989.
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Song, Yihao, and Yanfeng Shen. "Steerable Unidirectional Wave Emission From a Single Piezoelectric Transducer Using a Shape Memory Alloy Composite Metasurface." In ASME 2020 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/imece2020-23460.
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Abstract Structural Health Monitoring (SHM) and Nondestructive Evaluation (NDE) systems generally adopt piezoelectric transducers which emit omnidirectional wave fields. The achievement of directionality of guided wave generation will benefit the structural sensing purpose, which allows better detection and localization of the damage sites. In this study, a type of metamaterial ultrasonic radar is proposed for the steerable unidirectional wave manipulation. It contains a circular array of unit cells stuck in an aluminum plate which are delicately arranged in a circular fashion. Each unit cell is composed of a shape memory alloy substrate and a lead stub. The controllable bandgap of such metamaterial system can be achieved due to the stiffness change of nitinol between its martensite phase and austenite phase under a thermal load. This research starts with a Finite Element Model (FEM) of the unit cell to compute its frequency-wavenumber domain dispersion characteristics, demonstrating the adjustable bandgap feature. Then, numerical modeling of the metamaterial radar is performed by shifting the bandgap of one sector of the metasurface away from the excitation frequency. The modeling results demonstrate that the martensite phase metasurface area forms a bandgap region where guided wave energy cannot penetrate, while the bandgap of the austenite sector shifts away from the excitation frequency, opening up a transmission path for the ultrasonic waves. By rotating the austenite sector, the metamaterial structure can work like a wave emission radar, realizing of the steerable unidirectional wave radiation with a single transducer. Such an active metasurface possesses great application potential in future SHM and NDE systems.