77 FR 47490 - Shipping Coordinating Committee; Notice of Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-08

...): --Review and modernization of the GMDSS --Further development of the GMDSS master plan on shore-based facilities --Consideration of operational and technical coordination provisions of maritime safety... search and rescue procedures, including SAR training matters --Further development of the Global SAR Plan...

77 FR 72431 - Shipping Coordinating Committee; Notice of Committee Meeting

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-05

... GMDSS --Further development of the GMDSS master plan on shore-based facilities --Consideration of operational and technical coordination provisions of maritime safety information (MSI) services, including the... matters --Further development of the Global SAR Plan for the provision of maritime --SAR services...

Cluster of cases of severe acute respiratory syndrome among Toronto healthcare workers after implementation of infection control precautions: a case series.

PubMed

Ofner-Agostini, Marianna; Gravel, Denise; McDonald, L Clifford; Lem, Marcus; Sarwal, Shelley; McGeer, Allison; Green, Karen; Vearncombe, Mary; Roth, Virginia; Paton, Shirley; Loeb, Mark; Simor, Andrew

2006-05-01

To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented. A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions. Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age (+/-SD) of 39+/-2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increased number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered. Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.

Optimizing deep hyperthermia treatments: are locations of patient pain complaints correlated with modelled SAR peak locations?

NASA Astrophysics Data System (ADS)

Canters, R. A. M.; Franckena, M.; van der Zee, J.; van Rhoon, G. C.

2011-01-01

During deep hyperthermia treatment, patient pain complaints due to heating are common when maximizing power. Hence, there exists a good rationale to investigate whether the locations of predicted SAR peaks by hyperthermia treatment planning (HTP) are correlated with the locations of patient pain during treatment. A retrospective analysis was performed, using the treatment reports of 35 patients treated with deep hyperthermia controlled by extensive treatment planning. For various SAR indicators, the average distance from a SAR peak to a patient discomfort location was calculated, for each complaint. The investigated V0.1 closest (i.e. the part of the 0.1th SAR percentile closest to the patient complaint) performed the best, and leads to an average distance between the SAR peak and the complaint location of 3.9 cm. Other SAR indicators produced average distances that were all above 10 cm. Further, the predicted SAR peak location with V0.1 provides a 77% match with the region of complaint. The current study demonstrates that HTP is able to provide a global indication of the regions where hotspots during treatment will most likely occur. Further development of this technology is necessary in order to use HTP as a valuable toll for objective and advanced SAR steering. The latter is especially valid for applications that enable 3D SAR steering.

A new implementation of full resolution SBAS-DInSAR processing chain for the effective monitoring of structures and infrastructures

NASA Astrophysics Data System (ADS)

Bonano, Manuela; Buonanno, Sabatino; Ojha, Chandrakanta; Berardino, Paolo; Lanari, Riccardo; Zeni, Giovanni; Manunta, Michele

2017-04-01

The advanced DInSAR technique referred to as Small BAseline Subset (SBAS) algorithm has already largely demonstrated its effectiveness to carry out multi-scale and multi-platform surface deformation analyses relevant to both natural and man-made hazards. Thanks to its capability to generate displacement maps and long-term deformation time series at both regional (low resolution analysis) and local (full resolution analysis) spatial scales, it allows to get more insights on the spatial and temporal patterns of localized displacements relevant to single buildings and infrastructures over extended urban areas, with a key role in supporting risk mitigation and preservation activities. The extensive application of the multi-scale SBAS-DInSAR approach in many scientific contexts has gone hand in hand with new SAR satellite mission development, characterized by different frequency bands, spatial resolution, revisit times and ground coverage. This brought to the generation of huge DInSAR data stacks to be efficiently handled, processed and archived, with a strong impact on both the data storage and the computational requirements needed for generating the full resolution SBAS-DInSAR results. Accordingly, innovative and effective solutions for the automatic processing of massive SAR data archives and for the operational management of the derived SBAS-DInSAR products need to be designed and implemented, by exploiting the high efficiency (in terms of portability, scalability and computing performances) of the new ICT methodologies. In this work, we present a novel parallel implementation of the full resolution SBAS-DInSAR processing chain, aimed at investigating localized displacements affecting single buildings and infrastructures relevant to very large urban areas, relying on different granularity level parallelization strategies. The image granularity level is applied in most steps of the SBAS-DInSAR processing chain and exploits the multiprocessor systems with distributed memory. Moreover, in some processing steps very heavy from the computational point of view, the Graphical Processing Units (GPU) are exploited for the processing of blocks working on a pixel-by-pixel basis, requiring strong modifications on some key parts of the sequential full resolution SBAS-DInSAR processing chain. GPU processing is implemented by efficiently exploiting parallel processing architectures (as CUDA) for increasing the computing performances, in terms of optimization of the available GPU memory, as well as reduction of the Input/Output operations on the GPU and of the whole processing time for specific blocks w.r.t. the corresponding sequential implementation, particularly critical in presence of huge DInSAR datasets. Moreover, to efficiently handle the massive amount of DInSAR measurements provided by the new generation SAR constellations (CSK and Sentinel-1), we perform a proper re-design strategy aimed at the robust assimilation of the full resolution SBAS-DInSAR results into the web-based Geonode platform of the Spatial Data Infrastructure, thus allowing the efficient management, analysis and integration of the interferometric results with different data sources.

A VLSI implementation for synthetic aperture radar image processing

NASA Technical Reports Server (NTRS)

Premkumar, A.; Purviance, J.

1990-01-01

A simple physical model for the Synthetic Aperture Radar (SAR) is presented. This model explains the one dimensional and two dimensional nature of the received SAR signal in the range and azimuth directions. A time domain correlator, its algorithm, and features are explained. The correlator is ideally suited for VLSI implementation. A real time SAR architecture using these correlators is proposed. In the proposed architecture, the received SAR data is processed using one dimensional correlators for determining the range while two dimensional correlators are used to determine the azimuth of a target. The architecture uses only three different types of custom VLSI chips and a small amount of memory.

Clinical review: SARS - lessons in disaster management.

PubMed

Hawryluck, Laura; Lapinsky, Stephen E; Stewart, Thomas E

2005-08-01

Disaster management plans have traditionally been required to manage major traumatic events that create a large number of victims. Infectious diseases, whether they be natural (e.g. SARS [severe acute respiratory syndrome] and influenza) or the result of bioterrorism, have the potential to create a large influx of critically ill into our already strained hospital systems. With proper planning, hospitals, health care workers and our health care systems can be better prepared to deal with such an eventuality. This review explores the Toronto critical care experience of coping in the SARS outbreak disaster. Our health care system and, in particular, our critical care system were unprepared for this event, and as a result the impact that SARS had was worse than it could have been. Nonetheless, we were able to organize a response rapidly during the outbreak. By describing our successes and failures, we hope to help others to learn and avoid the problems we encountered as they develop their own disaster management plans in anticipation of similar future situations.

InSAR time series analysis of ALOS-2 ScanSAR data and its implications for NISAR

NASA Astrophysics Data System (ADS)

Liang, C.; Liu, Z.; Fielding, E. J.; Huang, M. H.; Burgmann, R.

2017-12-01

The JAXA's ALOS-2 mission was launched on May 24, 2014. It operates at L-band and can acquire data in multiple modes. ScanSAR is the main operational mode and has a 350 km swath, somewhat larger than the 250 km swath of the SweepSAR mode planned for the NASA-ISRO SAR (NISAR) mission. ALOS-2 has been acquiring a wealth of L-band InSAR data. These data are of particular value in areas of dense vegetation and high relief. The InSAR technical development for ALOS-2 also enables the preparation for the upcoming NISAR mission. We have been developing advanced InSAR processing techniques for ALOS-2 over the past two years. Here, we report the important issues for doing InSAR time series analysis using ALOS-2 ScanSAR data. First, we present ionospheric correction techniques for both regular ScanSAR InSAR and MAI (multiple aperture InSAR) ScanSAR InSAR. We demonstrate the large-scale ionospheric signals in the ScanSAR interferograms. They can be well mitigated by the correction techniques. Second, based on our technical development of burst-by-burst InSAR processing for ALOS-2 ScanSAR data, we find that the azimuth Frequency Modulation (FM) rate error is an important issue not only for MAI, but also for regular InSAR time series analysis. We identify phase errors caused by azimuth FM rate errors during the focusing process of ALOS-2 product. The consequence is mostly a range ramp in the InSAR time series result. This error exists in all of the time series results we have processed. We present the correction techniques for this error following a theoretical analysis. After corrections, we present high quality ALOS-2 ScanSAR InSAR time series results in a number of areas. The development for ALOS-2 can provide important implications for NISAR mission. For example, we find that in most cases the relative azimuth shift caused by ionosphere can be as large as 4 m in a large area imaged by ScanSAR. This azimuth shift is half of the 8 m azimuth resolution of the SweepSAR mode planned for NISAR, which implies that a good coregistration strategy for NISAR's SweepSAR mode is geometrical coregistration followed by MAI or spectral diversity analysis. Besides, our development also provides implications for the processing and system parameter requirements of NISAR, such as the accuracy requirement of azimuth FM rate and range timing.

Modified Polar-Format Software for Processing SAR Data

NASA Technical Reports Server (NTRS)

Chen, Curtis

2003-01-01

HMPF is a computer program that implements a modified polar-format algorithm for processing data from spaceborne synthetic-aperture radar (SAR) systems. Unlike prior polar-format processing algorithms, this algorithm is based on the assumption that the radar signal wavefronts are spherical rather than planar. The algorithm provides for resampling of SAR pulse data from slant range to radial distance from the center of a reference sphere that is nominally the local Earth surface. Then, invoking the projection-slice theorem, the resampled pulse data are Fourier-transformed over radial distance, arranged in the wavenumber domain according to the acquisition geometry, resampled to a Cartesian grid, and inverse-Fourier-transformed. The result of this process is the focused SAR image. HMPF, and perhaps other programs that implement variants of the algorithm, may give better accuracy than do prior algorithms for processing strip-map SAR data from high altitudes and may give better phase preservation relative to prior polar-format algorithms for processing spotlight-mode SAR data.

Implementation of the Generic Safety Analysis Report - Lessons Learned

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blanchard, A.

1999-06-02

The Savannah River Site has completed the development, review and approval process for the Generic Safety Analysis Report (GSAR) and implemented this information in facility SARs and BIOs. This includes the yearly revision of the GSAR and the facility-specific SARs. The process has provided us with several lessons learned.

Implementing a Strategy Awareness Raising Programme: Strategy Changes and Feedback

ERIC Educational Resources Information Center

Blanco, Maria; Pino, Margarita; Rodriguez, Beatriz

2010-01-01

This article reports on a collaborative action research study carried out on three groups of Spanish beginners during the implementation of a strategy awareness raising programme (SAR). The objective was to analyse the impact of the SAR programme on the students' learning process in three main areas: strategy awareness, strategy use in learning…

Asia Rice Crop Estimation and Monitoring (Asia-RiCE) for GEOGLAM

NASA Astrophysics Data System (ADS)

Oyoshi, K.; Tomiyama, N.; Okumura, T.; Sobue, S.

2013-12-01

Food security is a critical issue for the international community because of rapid population and economic growth, and climate change. In June 2011, the meeting of G20 agriculture ministers was held to discuss food security and food price volatility, and they agreed on an 'Action Plan on Food Price Volatility and Agriculture'. This plan includes a GEO Global Agricultural Monitoring (GEOGLAM) initiative. The aim of GEOGLAM is to reinforce the international community's ability to produce and disseminate relevant, timely, and accurate forecasts of agricultural production on regional, national, and global scales by utilizing remote sensing technology. GEOGLAM focused on four major grain crops, wheat, maize, soybeans and rice. In particular, Asian countries are responsible for approximately 90% of the world rice production and consumption, rice is the most significant cereal crop in Asian region. Hence, Asian space and agricultural agencies with an interest in the development of rice crop monitoring technology launched an Asia-Rice Crop Estimation & Monitoring (Asia-RiCE) component for the GEOGLAM initiative. In Asian region, rice is mainly cultivated in rainy season, and a large amount of cloud limits rice crop monitoring with optical sensors. But, Synthetic Aperture RADAR (SAR) is all-weather sensor and can observe land surface even if the area is covered by cloud. Therefore, SAR technology would be powerful tool to monitor rice crop in Asian region. Asia-RiCE team required mainly SAR observation data including ALOS-2, RISAT-1, Sentinel-1 and RADARSAT, TerraSAR-X, COSMO-SkyMed for Asia-RiCE GEOGLAM Phase 1 implementation (2013-2015) to the Committee on Earth Observations (CEOS) in the GEOGLAM-CEOS Global Agricultural Monitoring Co-community Meeting held in June 2013. And also, rice crop has complicated cropping systems such as rein-fed or irrigated cultivation, single, double or sometimes triple cropping. In addition, each agricultural field is smaller than that of other regions. The methodology for rice crop monitoring is different from that for other crops, and these characteristics make rice crop monitoring by Earth observation data more difficult and complicated. Now, Asian-RiCE team has selected four technical demonstration sites, Indonesia, Thailand, Vietnam (North and South) for Phase1A implementation (June 2013 to November 2014) to verify methodologies that estimate multi-season crop calendar, rice planted area, yield and production by the blending of Earth observation data including satellite data from SAR or optical sensor and in-situ data. We already developed some prototype systems for rice planed area mapping by SAR and agro-weather monitoring including soil moisture or drought index by microwave and optical data. These technologies would be contribute to the development of rice crop monitoring framework for Asia-RiCE. In this presentation, we introduce the framework and ongoing activities of Asia-RiCE component for GEOGLAM and developed systems for rice crop and agro-weather monitoring.

Search and Rescue. Auxiliary Operational Specialty Course. Student Text.

ERIC Educational Resources Information Center

Coast Guard, Washington, DC.

This text, based on the National Search and Rescue (SAR) Plan, was prepared to provide a course of study on common procedures for SAR operations so that any basically qualified person in the U.S. Coast Guard Auxiliary can effectively accomplish a SAR mission and act as on-scene commander if required. There are 13 chapters: Introduction to Search…

Lack of SARS transmission and U.S. SARS case-patient.

PubMed

Peck, Angela J; Newbern, E Claire; Feikin, Daniel R; Issakbaeva, Elmira T; Park, Benjamin J; Fehr, Jason; LaMonte, Ashley C; Le, Thong P; Burger, Terry L; Rhodes, Luther V; Weltman, Andre; Erdman, Dean; Ksiazek, Thomas G; Lingappa, Jairam R

2004-02-01

In early April 2003, severe acute respiratory syndrome (SARS) was diagnosed in a Pennsylvania resident after his exposure to persons with SARS in Toronto, Canada. To identify contacts of the case-patient and evaluate the risk for SARS transmission, a detailed epidemiologic investigation was performed. On the basis of this investigation, 26 persons (17 healthcare workers, 4 household contacts, and 5 others) were identified as having had close contact with this case-patient before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-associated coronavirus (SARS-CoV) infection to any close contact of this patient. This investigation documents that, under certain circumstances, SARS-CoV is not readily transmitted to close contacts, despite ample unprotected exposures. Improving the understanding of risk factors for transmission will help focus public health control measures.

SAR Speckle Noise Reduction Using Wiener Filter

NASA Technical Reports Server (NTRS)

Joo, T. H.; Held, D. N.

1983-01-01

Synthetic aperture radar (SAR) images are degraded by speckle. A multiplicative speckle noise model for SAR images is presented. Using this model, a Wiener filter is derived by minimizing the mean-squared error using the known speckle statistics. Implementation of the Wiener filter is discussed and experimental results are presented. Finally, possible improvements to this method are explored.

An acceleration framework for synthetic aperture radar algorithms

NASA Astrophysics Data System (ADS)

Kim, Youngsoo; Gloster, Clay S.; Alexander, Winser E.

2017-04-01

Algorithms for radar signal processing, such as Synthetic Aperture Radar (SAR) are computationally intensive and require considerable execution time on a general purpose processor. Reconfigurable logic can be used to off-load the primary computational kernel onto a custom computing machine in order to reduce execution time by an order of magnitude as compared to kernel execution on a general purpose processor. Specifically, Field Programmable Gate Arrays (FPGAs) can be used to accelerate these kernels using hardware-based custom logic implementations. In this paper, we demonstrate a framework for algorithm acceleration. We used SAR as a case study to illustrate the potential for algorithm acceleration offered by FPGAs. Initially, we profiled the SAR algorithm and implemented a homomorphic filter using a hardware implementation of the natural logarithm. Experimental results show a linear speedup by adding reasonably small processing elements in Field Programmable Gate Array (FPGA) as opposed to using a software implementation running on a typical general purpose processor.

Polarimetric Radar Observations of Forest State for Determination of Ecosystem Processes

NASA Technical Reports Server (NTRS)

Ulaby, Fawwaz T.; Dobson, M. Craig; Sharik, T.

1996-01-01

The objectives of this research are to test the hypotheses that ecologically significant forest state parameters may be estimated from SAR data. These include estimation of above ground biomass, plant water status, and near surface soil moisture under certain forest conditions. Test hypotheses in the northern hardwoods forest community, refine them if necessary, and establish techniques for retrieving this information from orbital SARs such as SIR-C/X-SAR. This report summarizes (1) recent progress, (2) significant results and (3) research plans concerning SIR-C/X-SAR research.

Advanced space-based InSAR risk analysis of planned and existing transportation infrastructure.

DOT National Transportation Integrated Search

2017-03-21

The purpose of this document is to summarize activities by Stanford University and : MDA Geospatial Services Inc. (MDA) to estimate surface deformation and associated : risk to transportation infrastructure using SAR Interferometric methods for the :...

Chirp Scaling Algorithms for SAR Processing

NASA Technical Reports Server (NTRS)

Jin, M.; Cheng, T.; Chen, M.

1993-01-01

The chirp scaling SAR processing algorithm is both accurate and efficient. Successful implementation requires proper selection of the interval of output samples, which is a function of the chirp interval, signal sampling rate, and signal bandwidth. Analysis indicates that for both airborne and spaceborne SAR applications in the slant range domain a linear chirp scaling is sufficient. To perform nonlinear interpolation process such as to output ground range SAR images, one can use a nonlinear chirp scaling interpolator presented in this paper.

Body Temperature Monitoring and SARS Fever Hotline, Taiwan

PubMed Central

Olowokure, Babatunde; Chang, Hong-Jen; Barwick, Rachel S.; Deng, Jou-Fang; Lee, Ming-Liang; Kuo, Steve Hsu-Sung; Su, Ih-Jen; Chen, Kow-Tong; Maloney, Susan A.

2004-01-01

In Taiwan, a temperature-monitoring campaign and hotline for severe acute respiratory syndrome (SARS) fever were implemented in June 2003. Among 1,966 calls, fever was recorded in 19% (n = 378); 18 persons at high risk for SARS were identified. In a cross-sectional telephone survey, 95% (n = 1,060) of households knew about the campaign and 7 households reported fever. PMID:15030716

On the Implementation of a Land Cover Classification System for SAR Images Using Khoros

NASA Technical Reports Server (NTRS)

Medina Revera, Edwin J.; Espinosa, Ramon Vasquez

1997-01-01

The Synthetic Aperture Radar (SAR) sensor is widely used to record data about the ground under all atmospheric conditions. The SAR acquired images have very good resolution which necessitates the development of a classification system that process the SAR images to extract useful information for different applications. In this work, a complete system for the land cover classification was designed and programmed using the Khoros, a data flow visual language environment, taking full advantages of the polymorphic data services that it provides. Image analysis was applied to SAR images to improve and automate the processes of recognition and classification of the different regions like mountains and lakes. Both unsupervised and supervised classification utilities were used. The unsupervised classification routines included the use of several Classification/Clustering algorithms like the K-means, ISO2, Weighted Minimum Distance, and the Localized Receptive Field (LRF) training/classifier. Different texture analysis approaches such as Invariant Moments, Fractal Dimension and Second Order statistics were implemented for supervised classification of the images. The results and conclusions for SAR image classification using the various unsupervised and supervised procedures are presented based on their accuracy and performance.

Spaceborne synthetic aperture radar: Current status and future directions. A report to the Committee on Earth Sciences, Space Studies Board, National Research Council

NASA Technical Reports Server (NTRS)

Evans, D. L. (Editor); Apel, J.; Arvidson, R.; Bindschadler, R.; Carsey, F.; Dozier, J.; Jezek, K.; Kasischke, E.; Li, F.; Melack, J.

1995-01-01

This report provides a context in which questions put forth by NASA's Office of Mission to Planet Earth (OMPTE) regarding the next steps in spaceborne synthetic aperture radar (SAR) science and technology can be addressed. It summarizes the state-of-the-art in theory, experimental design, technology, data analysis, and utilization of SAR data for studies of the Earth, and describes potential new applications. The report is divided into five science chapters and a technology assessment. The chapters summarize the value of existing SAR data and currently planned SAR systems, and identify gaps in observational capabilities needing to be filled to address the scientific questions. Cases where SAR provides complementary data to other (non-SAR) measurement techniques are also described. The chapter on technology assessment outlines SAR technology development which is critical not only to NASA's providing societally relevant geophysical parameters but to maintaining competitiveness in SAR technology, and promoting economic development.

Digital SAR processing using a fast polynomial transform

NASA Technical Reports Server (NTRS)

Butman, S.; Lipes, R.; Rubin, A.; Truong, T. K.

1981-01-01

A new digital processing algorithm based on the fast polynomial transform is developed for producing images from Synthetic Aperture Radar data. This algorithm enables the computation of the two dimensional cyclic correlation of the raw echo data with the impulse response of a point target, thereby reducing distortions inherent in one dimensional transforms. This SAR processing technique was evaluated on a general-purpose computer and an actual Seasat SAR image was produced. However, regular production runs will require a dedicated facility. It is expected that such a new SAR processing algorithm could provide the basis for a real-time SAR correlator implementation in the Deep Space Network.

Real time SAR processing

NASA Technical Reports Server (NTRS)

Premkumar, A. B.; Purviance, J. E.

1990-01-01

A simplified model for the SAR imaging problem is presented. The model is based on the geometry of the SAR system. Using this model an expression for the entire phase history of the received SAR signal is formulated. From the phase history, it is shown that the range and the azimuth coordinates for a point target image can be obtained by processing the phase information during the intrapulse and interpulse periods respectively. An architecture for a VLSI implementation for the SAR signal processor is presented which generates images in real time. The architecture uses a small number of chips, a new correlation processor, and an efficient azimuth correlation process.

UAVSAR and TerraSAR-X Based InSAR Detection of Localized Subsidence in the New Orleans Area

NASA Astrophysics Data System (ADS)

Blom, R. G.; An, K.; Jones, C. E.; Latini, D.

2014-12-01

Vulnerability of the US Gulf coast to inundation has received increased attention since hurricanes Katrina and Rita. Compounding effects of sea level rise, wetland loss, and regional and local subsidence makes flood protection a difficult challenge, and particularly for the New Orleans area. Key to flood protection is precise knowledge of elevations and elevation changes. Analysis of historical and continuing geodetic measurements show surprising complexity, including locations subsiding more rapidly than considered during planning of hurricane protection and coastal restoration projects. Combining traditional, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations can provide geographically dense constraints on surface deformation. The Gulf Coast environment is challenging for InSAR techniques, especially with systems not designed for interferometry. We use two InSAR capable systems, the L- band (24 cm wavelength) airborne JPL/NASA UAVSAR, and the DLR/EADS Astrium spaceborne TerraSAR X-band (3 cm wavelength), and compare results. First, we are applying pair-wise InSAR to the longer wavelength UAVSAR data to detect localized elevation changes potentially impacting flood protection infrastructure from 2009 - 2014. We focus on areas on and near flood protection infrastructure to identify changes indicative of subsidence, structural deformation, and/or seepage. The Spaceborne TerraSAR X-band SAR system has relatively frequent observations, and dense persistent scatterers in urban areas, enabling measurement of very small displacements. We compare L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period. Thus we can evaluate results from the different radar frequencies and analyses techniques. Preliminary results indicate subsidence features potentially of a variety of causes, including ground water pumping to post recent construction ground compaction. Our overall goal is to enable incorporation of InSAR into the decision making process via identification and delineation of areas of persistent subsidence, and provide input to improve monitoring and planning in flood risk areas.

From CryoSat-2 to Sentinel-3 and Beyond

NASA Astrophysics Data System (ADS)

Francis, R.

2011-12-01

CryoSat-2 carried into Earth orbit the first altimeter using SAR principles, although similar techniques had been used on earlier Venusian missions. Furthermore, it carries a second antenna and receive chain, and has been very carefully calibrated, allowing interferometry between these antennas. The results of the SAR mode and of the interferometer have met all expectations, with handsome margins. Even before the launch of CryoSat-2 the further development of this concept was underway with the radar for the oceanography mission Sentinel-3. While this radar, named SRAL (SAR Radar Altimeter) does not have the interferometer capability of CryoSat-2's SIRAL (SAR Interferometric Radar Altimeter), it does have a second frequency, to enable direct measurement of the delay induced by the ionospheric electron content. Sentinel-3 will have a sun-synchronous orbit, like ERS and EnviSat, and will have a similar latitudinal range: about 82° north and south, compared to CryoSat's 88°. Sentinel-3 will operate its radar altimeter in the high-resolution SAR mode over coastal oceans and inland water, and will revert to the more classical pulse-width limited mode over the open oceans. The SAR mode generates data at a high rate, so the major limiting factor is the amount of on-board storage. The power consumption is also higher, imposing less critical constraints. For sizing purposes the coastal oceans are defined as waters within 300 km of the continental shorelines. Sentinel-3 is expected to be launched in 2013 and be followed 18 months later by a second satellite of the same design. The next step in the development of this family of radar altimeters is Jason-CS, which will provide Continuity of Service to the existing Jason series of operational oceanography missions. Jason-CS has a very strong heritage from CryoSat but will fly the traditional Jason orbit, which covers latitudes up to 66° from a high altitude of 1330 km. The new radar is called Poseidon-4, to emphasise the connection to Jason, but its concept owes more to Sentinel-3's SRAL. It retains SRAL's dual frequencies and its SAR mode, but adds some further refinements. Most notably, an operating mode in which SAR operations and full performance pulse-width limited mode are available simultaneously, is under study. This would enable the benefits of SAR mode to be achieved over all ocean areas if the volume of data generated could be stored and downlinked to the ground. This problem only becomes tractable if an on-board processing system can be introduced to perform the first level of SAR processing, reducing the data volume by several orders of magnitude. This is also under study. The architecture of the radar has a further improvement, in the extension of digital technology further into the domain of analog radio-frequency electronics. While this is essentially invisible to the scientific user, it will yield an instrument with higher quality and markedly superior stability. The Jason-CS missions (at least two satellites are planned) are currently in a study phase with an implementation decision expected at the end of 2012. The planned launch date for the first mission is 2017.

GB-InSAR monitoring and observational method for landslide emergency management: the Montaguto earthflow (AV, Italy)

NASA Astrophysics Data System (ADS)

Ferrigno, Federica; Gigli, Giovanni; Fanti, Riccardo; Intrieri, Emanuele; Casagli, Nicola

2017-06-01

On 10 March 2010, because of the heavy rainfall in the preceding days, the Montaguto landslide (Southern Italy) reactivated, affecting both state road 90 Delle Puglie and the Rome-Bari railway. A similar event occurred on May 2005 and on September 2009. As a result, the National Civil Protection Department (DPC) started an accurate monitoring and analysis program. A monitoring project using the GB-InSAR (ground-based interferometric synthetic aperture radar) system was emplaced to investigate the landslide kinematics, plan urgent safety measures for risk mitigation and design long-term stabilization work.Here, we present the GB-InSAR monitoring system results and its applications in the observational method (OM) approach. GB-InSAR is an established instrument for long-term campaigns aimed at early warning and monitoring during construction works. Our paper further develops these aspects in that it highlights how the OM based on the GB-InSAR technique can produce savings in terms of cost and time in engineering projects without compromising safety. This study focuses on the key role played by the monitoring activities during the design and planning activities, with special reference to the emergency phase.

Geodetic integration of Sentinel-1A IW data using PSInSAR in Hungary

NASA Astrophysics Data System (ADS)

Farkas, Péter; Hevér, Renáta; Grenerczy, Gyula

2015-04-01

ESA's latest Synthetic Aperture Radar (SAR) mission Sentinel-1 is a huge step forward in SAR interferometry. With its default acquisition mode called the Interferometric Wide Swath Mode (IW) areas through all scales can be mapped with an excellent return time of 12 days (while only the Sentinel-1A is in orbit). Its operational data policy is also a novelty, it allows scientific users free and unlimited access to data. It implements a new type of ScanSAR mode called Terrain Observation with Progressive Scan (TOPS) SAR. It has the same resolution as ScanSAR but with better signal-to-noise ratio distribution. The bigger coverage is achieved by rotation of the antenna in the azimuth direction, therefore it requires very precise co-registration because even errors under a pixel accuracy can introduce azimuth phase variations caused by differences in Doppler-centroids. In our work we will summarize the benefits and the drawbacks of the IW mode. We would like to implement the processing chain of GAMMA Remote Sensing of such data for mapping surface motion with special attention to the co-registration step. Not only traditional InSAR but the advanced method of Persistent Scatterer InSAR (PSInSAR) will be performed and presented as well. PS coverage, along with coherence, is expected to be good due to the small perpendicular and temporal baselines. We would also like to integrate these measurements into national geodetic networks using common reference points. We have installed trihedral corner reflectors at some selected sites to aid precise collocation. Thus, we aim to demonstrate that Sentinel-1 can be effectively used for surface movement detection and monitoring and it can also provide valuable information for the improvement of our networks.

SARS: An Emerging Global Microbial Threat.

PubMed Central

Hughes, James M.

2004-01-01

In March 2003, the Institute of Medicine published an update to its 1992 landmark report on emerging infections. The new report, Microbial Threats to Health: Emergence, Detection, and Response, describes the current spectrum of global microbial threats, factors affecting their emergence or resurgence, and measures that should be undertaken to effectively address them. Coincident with this publication came increasing reports of severe atypical pneumonia of unknown etiology among persons in southeast Asia. This new disease, designated severe acute respiratory syndrome (SARS), spread globally in a matter of weeks, infecting primarily close contacts of index patients (e.g., household members and healthcare workers caring for index patients) but also resulting in community transmission in some areas. An unprecedented worldwide collaborative effort was undertaken to determine the cause of the illness and implement prevention measures. A previously unrecognized coronavirus was identified as the causative agent, and health officials throughout the world struggled to implement measures to contain its spread, including isolation of suspect SARS cases and quarantine of exposed persons. The emergence of SARS is a timely reminder of the need to expect the unexpected and to ensure strong national and global public health partnerships when preparing for and responding to infectious diseases. Effectively addressing the threat of SARS will require enhanced global infectious disease surveillance, the development of rapid diagnostics, new therapies, and vaccines, implementation of aggressive evidence-based infection control strategies, and effective communication. Images Fig. 2 Fig. 3 PMID:17060979

Digital SAR processing using a fast polynomial transform

NASA Technical Reports Server (NTRS)

Truong, T. K.; Lipes, R. G.; Butman, S. A.; Reed, I. S.; Rubin, A. L.

1984-01-01

A new digital processing algorithm based on the fast polynomial transform is developed for producing images from Synthetic Aperture Radar data. This algorithm enables the computation of the two dimensional cyclic correlation of the raw echo data with the impulse response of a point target, thereby reducing distortions inherent in one dimensional transforms. This SAR processing technique was evaluated on a general-purpose computer and an actual Seasat SAR image was produced. However, regular production runs will require a dedicated facility. It is expected that such a new SAR processing algorithm could provide the basis for a real-time SAR correlator implementation in the Deep Space Network. Previously announced in STAR as N82-11295

International standards for pandemic screening using infrared thermography

NASA Astrophysics Data System (ADS)

Pascoe, D. D.; Ring, E. F.; Mercer, J. B.; Snell, J.; Osborn, D.; Hedley-Whyte, J.

2010-03-01

The threat of a virulent strain of influenza, severe acute respiratory syndrome (SARS), tuberculosis, H1N1/A virus (swine flu) and possible mutations are a constant threat to global health. Implementation of pandemic infrared thermographic screening is based on the detection of febrile temperatures (inner canthus of the eyes) that are correlated with an infectious disease. Previous attempts at pandemic thermal screening have experienced problems (e.g. SARS outbreak, Singapore 2003) associated with the deployment plan, implementation and operation of the screening thermograph. Since this outbreak, the International Electrotechnical Commission has developed international standards that set minimum requirements for thermographic system fever screening and procedures that insure reliable and reproducible measurements. These requirements are published in IEC 80601-2-59:2008, Medical electrical equipment - Part 2-59: Particular requirements for the basic safety and essential performance of screening thermographs for human febrile temperature screening. The International Organization for Standardization has developed ISO/TR 13154:2009, Medical Electrical Equipment - which provides deployment, implementation and operational guidelines for identifying febrile humans using a screening thermograph. These new standards includes recommendations for camera calibrations, use of black body radiators, view field, focus, pixels within measurement site, image positioning, and deployment locations. Many current uses of thermographic screening at airports do not take into account critical issues addressed in the new standard, and are operating below the necessary effectiveness and efficiency. These documents, related thermal research, implications for epidemiology screening, and the future impact on medical thermography are discussed.

InSAR remote sensing for performance monitoring of transportation infrastructure at the network level.

DOT National Transportation Integrated Search

2016-01-11

The goal of the project was the implementation of interferometric synthetic aperture radar : (InSAR) monitoring techniques to allow for early detection of geohazard, potentially : affecting the transportation infrastructure, as well as the monitoring...

Geologic process studies using Synthetic Aperture Radar (SAR) data

NASA Technical Reports Server (NTRS)

Evans, Diane L.

1992-01-01

The use of SAR data to study geologic processes for better understanding of recent tectonic activity and climate change as well as the mitigation of geologic hazards and exploration for nonrenewable resources is discussed. The geologic processes that are particularly amenable to SAR-based data include volcanism; soil erosion, degradation, and redistribution; coastal erosion and inundation; glacier fluctuations; permafrost; and crustal motions. When SAR data are combined with data from other planned spaceborne sensors including ESA ERS, the Japanese Earth Resources Satellite, and the Canadian Radarsat, it will be possible to build a time-series view of temporal changes over many regions of earth.

Infrastructure stability surveillance with high resolution InSAR

NASA Astrophysics Data System (ADS)

Balz, Timo; Düring, Ralf

2017-02-01

The construction of new infrastructure in largely unknown and difficult environments, as it is necessary for the construction of the New Silk Road, can lead to a decreased stability along the construction site, leading to an increase in landslide risk and deformation caused by surface motion. This generally requires a thorough pre-analysis and consecutive surveillance of the deformation patterns to ensure the stability and safety of the infrastructure projects. Interferometric SAR (InSAR) and the derived techniques of multi-baseline InSAR are very powerful tools for a large area observation of surface deformation patterns. With InSAR and deriver techniques, the topographic height and the surface motion can be estimated for large areas, making it an ideal tool for supporting the planning, construction, and safety surveillance of new infrastructure elements in remote areas.

Semi-physical Simulation of the Airborne InSAR based on Rigorous Geometric Model and Real Navigation Data

NASA Astrophysics Data System (ADS)

Changyong, Dou; Huadong, Guo; Chunming, Han; yuquan, Liu; Xijuan, Yue; Yinghui, Zhao

2014-03-01

Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc.

Analysis of deformation patterns through advanced DINSAR techniques in Istanbul megacity

NASA Astrophysics Data System (ADS)

Balik Sanli, F.; Calò, F.; Abdikan, S.; Pepe, A.; Gorum, T.

2014-09-01

As result of the Turkey's economic growth and heavy migration processes from rural areas, Istanbul has experienced a high urbanization rate, with severe impacts on the environment in terms of natural resources pressure, land-cover changes and uncontrolled sprawl. As a consequence, the city became extremely vulnerable to natural and man-made hazards, inducing ground deformation phenomena that threaten buildings and infrastructures and often cause significant socio-economic losses. Therefore, the detection and monitoring of such deformation patterns is of primary importance for hazard and risk assessment as well as for the design and implementation of effective mitigation strategies. Aim of this work is to analyze the spatial distribution and temporal evolution of deformations affecting the Istanbul metropolitan area, by exploiting advanced Differential SAR Interferometry (DInSAR) techniques. In particular, we apply the Small BAseline Subset (SBAS) approach to a dataset of 43 TerraSAR-X images acquired, between November 2010 and June 2012, along descending orbits with an 11-day revisit time and a 3 m × 3 m spatial resolution. The SBAS processing allowed us to remotely detect and monitor subsidence patterns over all the urban area as well as to provide detailed information at the scale of the single building. Such SBAS measurements, effectively integrated with ground-based monitoring data and thematic maps, allows to explore the relationship between the detected deformation phenomena and urbanization, contributing to improve the urban planning and management.

ScanSAR interferometric processing using existing standard InSAR software for measuring large scale land deformation

NASA Astrophysics Data System (ADS)

Liang, Cunren; Zeng, Qiming; Jia, Jianying; Jiao, Jian; Cui, Xi'ai

2013-02-01

Scanning synthetic aperture radar (ScanSAR) mode is an efficient way to map large scale geophysical phenomena at low cost. The work presented in this paper is dedicated to ScanSAR interferometric processing and its implementation by making full use of existing standard interferometric synthetic aperture radar (InSAR) software. We first discuss the properties of the ScanSAR signal and its phase-preserved focusing using the full aperture algorithm in terms of interferometry. Then a complete interferometric processing flow is proposed. The standard ScanSAR product is decoded subswath by subswath with burst gaps padded with zero-pulses, followed by a Doppler centroid frequency estimation for each subswath and a polynomial fit of all of the subswaths for the whole scene. The burst synchronization of the interferometric pair is then calculated, and only the synchronized pulses are kept for further interferometric processing. After the complex conjugate multiplication of the interferometric pair, the residual non-integer pulse repetition interval (PRI) part between adjacent bursts caused by zero padding is compensated by resampling using a sinc kernel. The subswath interferograms are then mosaicked, in which a method is proposed to remove the subswath discontinuities in the overlap area. Then the following interferometric processing goes back to the traditional stripmap processing flow. A processor written with C and Fortran languages and controlled by Perl scripts is developed to implement these algorithms and processing flow based on the JPL/Caltech Repeat Orbit Interferometry PACkage (ROI_PAC). Finally, we use the processor to process ScanSAR data from the Envisat and ALOS satellites and obtain large scale deformation maps in the radar line-of-sight (LOS) direction.

ALOS2-Indonesia REDD+ Experiment (AIREX): Soil Pool Carbon Application

NASA Astrophysics Data System (ADS)

Raimadoya, M.; Kristijono, A.; Sudiana, N.; Sumawinata, B.; Suwardi; Santoso, E.; Mahargo, D.; Sudarman, S.; Mattikainen, M.

2015-04-01

The bilateral REDD+ agreement between Indonesia and Norway [1] has scheduled that performance based result phase will be started in 2014. Therefore, a transparent and reliable Monitoring, Reporting and V erification (MRV) system for the following carbon pools: (1) biomass, (2) dead organic matter (DOM), and (3) soil, is required to be ready prior to the performance based phase. While the biomass pool could be acquired by space-borne radar (SAR) application i.e. SAR Interferometry (In-SAR) and Polarimetric SAR Interferometry (Pol-InSAR), the method for soil pool is still needed to be developed.A study was implemented in a test site located in the pulp plantation concession of Teluk Meranti Estate, Riau Andalan Pulp and Paper (RAPP), Pelalawan District, Riau Province, Indonesia. The study was intended to evaluate the possibility to estimate soil pool carbon with radar technology. For this purpose, a combination of spaceborne SAR (ALOS/PALSAR) and Ground Penetrating Radar (200 MHz IDS 200 MHz IDS GPR) were used in this exercise.The initial result this study provides a promising outcome for improved soil pool carbon estimation in tropical peat forest condition. The volume estimation of peat soil could be measured from the combination of spaceborne SAR and GPR. Based on this volume, total carbon content can be generated. However, the application of this approach has several limitation such as: (1) GPR survey can only be implemented during the dry season, (2) Rugged Terrain Antenna (RTA) type of GPR should be used for smooth GPR survey in the surface of peat soil which covered by DOM, and (3) the map of peat soil extent by spaceborne SAR need to be improved.

Evaluating the performance of Sentinel-3 SRAL SAR Altimetry in the Coastal and Open Ocean, and developing improved retrieval methods - The ESA SCOOP Project.

NASA Astrophysics Data System (ADS)

Benveniste, J.; Cotton, D.; Moreau, T.; Varona, E.; Roca, M.; Cipollini, P.; Cancet, M.; Martin, F.; Fenoglio-Marc, L.; Naeije, M.; Fernandes, J.; Restano, M.; Ambrozio, A.

2016-12-01

The ESA Sentinel-3 satellite, launched in February 2016 as a part of the Copernicus programme, is the second satellite to operate a SAR mode altimeter. The Sentinel 3 Synthetic Aperture Radar Altimeter (SRAL) is based on the heritage from Cryosat-2, but this time complemented by a Microwave Radiometer (MWR) to provide a wet troposphere correction, and operating at Ku and C-Bands to provide an accurate along-track ionospheric correction. Together this instrument package, including both GPS and DORIS instruments for accurate positioning, allows accurate measurements of sea surface height over the ocean, as well as measurements of significant wave height and surface wind speed. SCOOP (SAR Altimetry Coastal & Open Ocean Performance) is a project funded under the ESA SEOM (Scientific Exploitation of Operational Missions) Programme Element, started in September 2015, to characterise the expected performance of Sentinel-3 SRAL SAR mode altimeter products, in the coastal zone and open-ocean, and then to develop and evaluate enhancements to the baseline processing scheme in terms of improvements to ocean measurements. There is also a work package to develop and evaluate an improved Wet Troposphere correction for Sentinel-3, based on the measurements from the on-board MWR, further enhanced mostly in the coastal and polar regions using third party data, and provide recommendations for use. At the end of the project recommendations for further developments and implementations will be provided through a scientific roadmap. In this presentation we provide an overview of the SCOOP project, highlighting the key deliverables and discussing the potential impact of the results in terms of the application of delay-Doppler (SAR) altimeter measurements over the open-ocean and coastal zone. We also present the initial results from the project, including: Key findings from a review of the current "state-of-the-art" for SAR altimetry, Specification of the initial "reference" delay-Doppler and echo modelling /retracking processing schemes, Evaluation of the initial Test Data Set in the Open Ocean and Coastal Zone Overview of modifications planned to the reference delay-Doppler and echo modelling/ re-tracking processing schemes.

SARS and health worker safety: lessons for influenza pandemic planning and response.

PubMed

Possamai, Mario A

2007-01-01

The outbreak of severe acute respiratory syndrome (SARS) in 2003 provided valuable lessons for protecting health workers during an influenza pandemic or other public health crisis. In its final report, the SARS Commission concluded that a key lesson in worker safety was the precautionary principle. It stated that reasonable actions to reduce risk should not await scientific certainty. As recommended by the SARS Commission, this principle has now been enshrined in the Health Protection and Promotion Act (2007), Ontario's public health legislation and in Ontario's influenza pandemic plan. Another vital lesson for worker safety involves the occupational hygiene concept of a hierarchy of controls. It takes a holistic approach to worker safety, addressing each hazard through control at the source of the hazard, along the path between the worker and the hazard and, lastly, at the worker. Absent such an approach, the SARS Commission said worker safety may focus solely on a particular piece of personal protective equipment, such as an N95 respirator (important as it may be), or on specific policies and procedures, such as fit testing the N95 respirator to the wearer (significant as it may be). In worker safety, said the commission, the integrated whole is greater than the uncoordinated parts. The third and final worker safety lesson of SARS is the importance of having a robust safety culture in the workplace in which workers play an integral role in promoting a safe workplace.

SARS: Key factors in crisis management.

PubMed

Tseng, Hsin-Chao; Chen, Thai-Form; Chou, Shieu-Ming

2005-03-01

This study was conducted at a single hospital selected in Taipei during the SARS (Severe Acute Respiratory Syndrome) outbreak from March to July, 2003 in Taiwan. During this period of time, 104 SARS patients were admitted to the hospital. There were no negative reports related to the selected hospital despite its being located right in the center of an area struck by the epidemic. The purpose of this study was to identify the key factors enabling the hospital to survive SARS unscathed. Data were collected from in-depth interviews with the nursing directors and nursing managers of the SARS units, along with a review of relevant hospital documents. The five key elements identified as survival factors during this SARS crisis are as follows: 1. good control of timing for crisis management, 2. careful decision-making, 3. thorough implementation, 4. effective communication, and 5. trust between management and employees. The results of this study reconfirmed the selected hospital as a model for good crisis management during the SARS epidemic.

Quarantine for SARS, Taiwan

PubMed Central

King, Chwan-Chuan; Chen, Cathy W. S.; Ho, Mei-Shang; Lee, Jen-Yu; Liu, Feng-Chi; Wu, Yi-Chun

2005-01-01

During the 2003 outbreak of severe acute respiratory syndrome (SARS) in Taiwan, >150,000 persons were quarantined, 24 of whom were later found to have laboratory-confirmed SARS-coronavirus (SARS-CoV) infection. Since no evidence exists that SARS-CoV is infective before the onset of symptoms and the quarantined persons were exposed but not symptomatic, we thought the quarantine's effectiveness should be investigated. Using the Taiwan quarantine data, we found that the onset-to-diagnosis time of previously quarantined confirmed case-patients was significantly shortened compared to that for those who had not been quarantined. Thus, quarantine for SARS in Taiwan screened potentially infective persons for swift diagnosis and hospitalization after onset, thereby indirectly reducing infections. Full-scale quarantine measures implemented on April 28 led to a significant improvement in onset-to-diagnosis time of all SARS patients, regardless of previous quarantine status. We discuss the temporal effects of quarantine measures and other interventions on detection and isolation as well as the potential usefulness of quarantine in faster identification of persons with SARS and in improving isolation measures. PMID:15752447

New Ground Truth Capability from InSAR Time Series Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buckley, S; Vincent, P; Yang, D

2005-07-13

We demonstrate that next-generation interferometric synthetic aperture radar (InSAR) processing techniques applied to existing data provide rich InSAR ground truth content for exploitation in seismic source identification. InSAR time series analyses utilize tens of interferograms and can be implemented in different ways. In one such approach, conventional InSAR displacement maps are inverted in a final post-processing step. Alternatively, computationally intensive data reduction can be performed with specialized InSAR processing algorithms. The typical final result of these approaches is a synthesized set of cumulative displacement maps. Examples from our recent work demonstrate that these InSAR processing techniques can provide appealing newmore » ground truth capabilities. We construct movies showing the areal and temporal evolution of deformation associated with previous nuclear tests. In other analyses, we extract time histories of centimeter-scale surface displacement associated with tunneling. The potential exists to identify millimeter per year surface movements when sufficient data exists for InSAR techniques to isolate and remove phase signatures associated with digital elevation model errors and the atmosphere.« less

RADAR Reveals Titan Topography

NASA Technical Reports Server (NTRS)

Kirk, R. L.; Callahan, P.; Seu, R.; Lorenz, R. D.; Paganelli, F.; Lopes, R.; Elachi, C.

2005-01-01

The Cassini Titan RADAR Mapper is a K(sub u)-band (13.78 GHz, lambda = 2.17 cm) linear polarized RADAR instrument capable of operating in synthetic aperture (SAR), scatterometer, altimeter and radiometer modes. During the first targeted flyby of Titan on 26 October, 2004 (referred to as Ta) observations were made in all modes. Evidence for topographic relief based on the Ta altimetry and SAR data are presented here. Additional SAR and altimetry observations are planned for the T3 encounter on 15 February, 2005, but have not been carried out at this writing. Results from the T3 encounter relevant to topography will be included in our presentation. Data obtained in the Ta encounter include a SAR image swath

Mission design for NISAR repeat-pass Interferometric SAR

NASA Astrophysics Data System (ADS)

Alvarez-Salazar, Oscar; Hatch, Sara; Rocca, Jennifer; Rosen, Paul; Shaffer, Scott; Shen, Yuhsyen; Sweetser, Theodore; Xaypraseuth, Peter

2014-10-01

The proposed spaceborne NASA-ISRO SAR (NISAR) mission would use the repeat-pass interferometric Synthetic Aperture Radar (InSAR) technique to measure the changing shape of Earth's surface at the centimeter scale in support of investigations in solid Earth and cryospheric sciences. Repeat-pass InSAR relies on multiple SAR observations acquired from nearly identical positions of the spacecraft as seen from the ground. Consequently, there are tight constraints on the repeatability of the orbit, and given the narrow field of view of the radar antenna beam, on the repeatability of the beam pointing. The quality and accuracy of the InSAR data depend on highly precise control of both orbital position and observatory pointing throughout the science observation life of the mission. This paper describes preliminary NISAR requirements and rationale for orbit repeatability and attitude control in order to meet science requirements. A preliminary error budget allocation and an implementation approach to meet these allocations are also discussed.

An Adaptive Ship Detection Scheme for Spaceborne SAR Imagery

PubMed Central

Leng, Xiangguang; Ji, Kefeng; Zhou, Shilin; Xing, Xiangwei; Zou, Huanxin

2016-01-01

With the rapid development of spaceborne synthetic aperture radar (SAR) and the increasing need of ship detection, research on adaptive ship detection in spaceborne SAR imagery is of great importance. Focusing on practical problems of ship detection, this paper presents a highly adaptive ship detection scheme for spaceborne SAR imagery. It is able to process a wide range of sensors, imaging modes and resolutions. Two main stages are identified in this paper, namely: ship candidate detection and ship discrimination. Firstly, this paper proposes an adaptive land masking method using ship size and pixel size. Secondly, taking into account the imaging mode, incidence angle, and polarization channel of SAR imagery, it implements adaptive ship candidate detection in spaceborne SAR imagery by applying different strategies to different resolution SAR images. Finally, aiming at different types of typical false alarms, this paper proposes a comprehensive ship discrimination method in spaceborne SAR imagery based on confidence level and complexity analysis. Experimental results based on RADARSAT-1, RADARSAT-2, TerraSAR-X, RS-1, and RS-3 images demonstrate that the adaptive scheme proposed in this paper is able to detect ship targets in a fast, efficient and robust way. PMID:27563902

Understanding the T cell immune response in SARS coronavirus infection

PubMed Central

Janice Oh, Hsueh-Ling; Ken-En Gan, Samuel; Bertoletti, Antonio; Tan, Yee-Joo

2012-01-01

The severe acute respiratory syndrome (SARS) epidemic started in late 2002 and swiftly spread across 5 continents with a mortality rate of around 10%. Although the epidemic was eventually controlled through the implementation of strict quarantine measures, there continues a need to investigate the SARS coronavirus (SARS-CoV) and develop interventions should it re-emerge. Numerous studies have shown that neutralizing antibodies against the virus can be found in patients infected with SARS-CoV within days upon the onset of illness and lasting up to several months. In contrast, there is little data on the kinetics of T cell responses during SARS-CoV infection and little is known about their role in the recovery process. However, recent studies in mice suggest the importance of T cells in viral clearance during SARS-CoV infection. Moreover, a growing number of studies have investigated the memory T cell responses in recovered SARS patients. This review covers the available literature on the emerging importance of T cell responses in SARS-CoV infection, particularly on the mapping of cytotoxic T lymphocyte (CTL) epitopes, longevity, polyfunctionality and human leukocyte antigen (HLA) association as well as their potential implications on treatment and vaccine development. PMID:26038429

Understanding the T cell immune response in SARS coronavirus infection.

PubMed

Janice Oh, Hsueh-Ling; Ken-En Gan, Samuel; Bertoletti, Antonio; Tan, Yee-Joo

2012-09-01

The severe acute respiratory syndrome (SARS) epidemic started in late 2002 and swiftly spread across 5 continents with a mortality rate of around 10%. Although the epidemic was eventually controlled through the implementation of strict quarantine measures, there continues a need to investigate the SARS coronavirus (SARS-CoV) and develop interventions should it re-emerge. Numerous studies have shown that neutralizing antibodies against the virus can be found in patients infected with SARS-CoV within days upon the onset of illness and lasting up to several months. In contrast, there is little data on the kinetics of T cell responses during SARS-CoV infection and little is known about their role in the recovery process. However, recent studies in mice suggest the importance of T cells in viral clearance during SARS-CoV infection. Moreover, a growing number of studies have investigated the memory T cell responses in recovered SARS patients. This review covers the available literature on the emerging importance of T cell responses in SARS-CoV infection, particularly on the mapping of cytotoxic T lymphocyte (CTL) epitopes, longevity, polyfunctionality and human leukocyte antigen (HLA) association as well as their potential implications on treatment and vaccine development.

High-Explosives Applications Facility (HEAF)

NASA Astrophysics Data System (ADS)

Morse, J. L.; Weingart, R. C.

1989-03-01

This Safety Analysis Report (SAR) reviews the safety and environmental aspects of the High Explosives Applications Facility (HEAF). Topics covered include the site selected for the HEAF, safety design criteria, operations planned within the facility, and the safety and environmental analyses performed on this project to date. Provided in the Summary section is a review of hazards and the analyses, conclusions, and operating limits developed in this SAR. Appendices provide supporting documents relating to this SAR. This SAR is required by the LLNL Health and Safety Manual and DOE Order 5481.1B(2) to document the safety analysis efforts. The SAR was assembled by the Hazards Control Department, B-Division, and HEAF project personnel. This document was reviewed by B Division, the Chemistry Department, the Hazards Control Department, the Laboratory Associate Director for Administration and Operations, and the Associate Directors ultimately responsible for HEAF operations.

Influence of patient mispositioning on SAR distribution and simulated temperature in regional deep hyperthermia

NASA Astrophysics Data System (ADS)

Aklan, Bassim; Gierse, Pia; Hartmann, Josefin; Ott, Oliver J.; Fietkau, Rainer; Bert, Christoph

2017-06-01

Patient positioning plays an important role in regional deep hyperthermia to obtain a successful hyperthermia treatment. In this study, the influence of possible patient mispositioning was systematically assessed on specific absorption rate (SAR) and temperature distribution. With a finite difference time domain approach, the SAR and temperature distributions were predicted for six patients at 312 positions. Patient displacements and rotations as well as the combination of both were considered inside the Sigma-Eye applicator. Position sensitivity is assessed for hyperthermia treatment planning -guided steering, which relies on model-based optimization of the SAR and temperature distribution. The evaluation of the patient mispositioning was done with and without optimization. The evaluation without optimization was made by creating a treatment plan for the patient reference position in the center of the applicator and applied for all other positions, while the evaluation with optimization was based on creating an individual plan for each position. The parameter T90 was used for the temperature evaluation, which was defined as the temperature that covers 90% of the gross tumor volume (GTV). Furthermore, the hotspot tumor quotient (HTQ) was used as a goal function to assess the quality of the SAR and temperature distribution. The T90 was shown considerably dependent on the position within the applicator. Without optimization, the T90 was clearly decreased below 40 °C by patient shifts and the combination of shifts and rotations. However, the application of optimization for each positon led to an increase of T90 in the GTV. Position inaccuracies of less than 1 cm in the X-and Y-directions and 2 cm in the Z-direction, resulted in an increase of HTQ of less than 5%, which does not significantly affect the SAR and temperature distribution. Current positioning precision is sufficient in the X (right-left)-direction, but position accuracy is required in the Y-and Z-directions.

Baseline Error Analysis and Experimental Validation for Height Measurement of Formation Insar Satellite

NASA Astrophysics Data System (ADS)

Gao, X.; Li, T.; Zhang, X.; Geng, X.

2018-04-01

In this paper, we proposed the stochastic model of InSAR height measurement by considering the interferometric geometry of InSAR height measurement. The model directly described the relationship between baseline error and height measurement error. Then the simulation analysis in combination with TanDEM-X parameters was implemented to quantitatively evaluate the influence of baseline error to height measurement. Furthermore, the whole emulation validation of InSAR stochastic model was performed on the basis of SRTM DEM and TanDEM-X parameters. The spatial distribution characteristics and error propagation rule of InSAR height measurement were fully evaluated.

Feasibility of Using Synthetic Aperture Radar to Aid UAV Navigation

PubMed Central

Nitti, Davide O.; Bovenga, Fabio; Chiaradia, Maria T.; Greco, Mario; Pinelli, Gianpaolo

2015-01-01

This study explores the potential of Synthetic Aperture Radar (SAR) to aid Unmanned Aerial Vehicle (UAV) navigation when Inertial Navigation System (INS) measurements are not accurate enough to eliminate drifts from a planned trajectory. This problem can affect medium-altitude long-endurance (MALE) UAV class, which permits heavy and wide payloads (as required by SAR) and flights for thousands of kilometres accumulating large drifts. The basic idea is to infer position and attitude of an aerial platform by inspecting both amplitude and phase of SAR images acquired onboard. For the amplitude-based approach, the system navigation corrections are obtained by matching the actual coordinates of ground landmarks with those automatically extracted from the SAR image. When the use of SAR amplitude is unfeasible, the phase content can be exploited through SAR interferometry by using a reference Digital Terrain Model (DTM). A feasibility analysis was carried out to derive system requirements by exploring both radiometric and geometric parameters of the acquisition setting. We showed that MALE UAV, specific commercial navigation sensors and SAR systems, typical landmark position accuracy and classes, and available DTMs lead to estimate UAV coordinates with errors bounded within ±12 m, thus making feasible the proposed SAR-based backup system. PMID:26225977

Feasibility of Using Synthetic Aperture Radar to Aid UAV Navigation.

PubMed

Nitti, Davide O; Bovenga, Fabio; Chiaradia, Maria T; Greco, Mario; Pinelli, Gianpaolo

2015-07-28

This study explores the potential of Synthetic Aperture Radar (SAR) to aid Unmanned Aerial Vehicle (UAV) navigation when Inertial Navigation System (INS) measurements are not accurate enough to eliminate drifts from a planned trajectory. This problem can affect medium-altitude long-endurance (MALE) UAV class, which permits heavy and wide payloads (as required by SAR) and flights for thousands of kilometres accumulating large drifts. The basic idea is to infer position and attitude of an aerial platform by inspecting both amplitude and phase of SAR images acquired onboard. For the amplitude-based approach, the system navigation corrections are obtained by matching the actual coordinates of ground landmarks with those automatically extracted from the SAR image. When the use of SAR amplitude is unfeasible, the phase content can be exploited through SAR interferometry by using a reference Digital Terrain Model (DTM). A feasibility analysis was carried out to derive system requirements by exploring both radiometric and geometric parameters of the acquisition setting. We showed that MALE UAV, specific commercial navigation sensors and SAR systems, typical landmark position accuracy and classes, and available DTMs lead to estimated UAV coordinates with errors bounded within ±12 m, thus making feasible the proposed SAR-based backup system.

Accuracy of available methods for quantifying the heat power generation of nanoparticles for magnetic hyperthermia.

PubMed

Andreu, Irene; Natividad, Eva

2013-12-01

In magnetic hyperthermia, characterising the specific functionality of magnetic nanoparticle arrangements is essential to plan the therapies by simulating maximum achievable temperatures. This functionality, i.e. the heat power released upon application of an alternating magnetic field, is quantified by means of the specific absorption rate (SAR), also referred to as specific loss power (SLP). Many research groups are currently involved in the SAR/SLP determination of newly synthesised materials by several methods, either magnetic or calorimetric, some of which are affected by important and unquantifiable uncertainties that may turn measurements into rough estimates. This paper reviews all these methods, discussing in particular sources of uncertainties, as well as their possible minimisation. In general, magnetic methods, although accurate, do not operate in the conditions of magnetic hyperthermia. Calorimetric methods do, but the easiest to implement, the initial-slope method in isoperibol conditions, derives inaccuracies coming from the lack of matching between thermal models, experimental set-ups and measuring conditions, while the most accurate, the pulse-heating method in adiabatic conditions, requires more complex set-ups.

Investigating the Mechanisms of Action and the Identification of Breast Carcinogens by Computational Analysis of Female Rodent Carcinogens

DTIC Science & Technology

2005-08-01

QSAR in Environmental Researth was accepted and published in April of 2005. The manuscript described the cat -SAR program in detail. We note the...analysis of this data yielded a very good model. As such, this was a suitable dataset on which to develop and test the cat -SAR program. A copy of the...developed and validated (i.e., a-c) as planned in MCASE and then with the cat -SAR program. We have also updated rodent carcinogenicity models so that

MuLoG, or How to Apply Gaussian Denoisers to Multi-Channel SAR Speckle Reduction?

PubMed

Deledalle, Charles-Alban; Denis, Loic; Tabti, Sonia; Tupin, Florence

2017-09-01

Speckle reduction is a longstanding topic in synthetic aperture radar (SAR) imaging. Since most current and planned SAR imaging satellites operate in polarimetric, interferometric, or tomographic modes, SAR images are multi-channel and speckle reduction techniques must jointly process all channels to recover polarimetric and interferometric information. The distinctive nature of SAR signal (complex-valued, corrupted by multiplicative fluctuations) calls for the development of specialized methods for speckle reduction. Image denoising is a very active topic in image processing with a wide variety of approaches and many denoising algorithms available, almost always designed for additive Gaussian noise suppression. This paper proposes a general scheme, called MuLoG (MUlti-channel LOgarithm with Gaussian denoising), to include such Gaussian denoisers within a multi-channel SAR speckle reduction technique. A new family of speckle reduction algorithms can thus be obtained, benefiting from the ongoing progress in Gaussian denoising, and offering several speckle reduction results often displaying method-specific artifacts that can be dismissed by comparison between results.

Towards "Biliteracy and Trilingualism" in Hong Kong (SAR): Problems, Dilemmas and Stakeholders' Views

ERIC Educational Resources Information Center

Li, David C. S.

2009-01-01

Despite the Hong Kong SAR (Special Administrative Region) government's determination to implement the "mother tongue education" policy amid strong social resistance one year after the handover, English remains a prestigious language in society. The need for Putonghua (Mandarin/Standard Chinese) is also increasing following ever-expanding…

Self-Assessment and Development Planning for Adult and Community Learning Providers.

ERIC Educational Resources Information Center

Kenway, Mike; Reisenberger, Anna

This document is designed to help adult and community learning (ACL) services across the United Kingdom complete the annual self-assessment reports (SARs). The guide begins with background information on the purposes of self-assessment, the new context of ACL and the elements and format of the new SARs. The remaining four sections examine the…

NASA's NI-SAR Observing Strategy and Data Availability for Agricultural Monitoring and Assessment

NASA Astrophysics Data System (ADS)

Siqueira, P.; Dubayah, R.; Kellndorfer, J. M.; Saatchi, S. S.; Chapman, B. D.

2014-12-01

The monitoring and characterization of global crop development by remote sensing is a complex task, in part, because of the time varying nature of the target and the diversity of crop types and agricultural practices that vary worldwide. While some of these difficulties are overcome with the availability of national and market-derived resources (e.g. publication of crop statistics by the USDA and FAO), monitoring by remote sensing has the ability of augmenting those resources to better identify changes over time, and to provide timely assessments for the current year's production. Of the remote sensing techniques that are used for agricultural applications, optical observations of NDVI from Landsat, AVHRR, MODIS and similar sensors have historically provided the majority of data that is used by the community. In addition, radiometer and radar sensors, are often used for estimating soil moisture and structural information for these agricultural regions. The combination of these remote sensing datasets and national resources constitutes the state of the art for crop monitoring and yield forecasts. To help improve these crop monitoring efforts in the future, the joint NASA-ISRO SAR mission known as NI-SAR is being planned for launch in 2020, and will have L- and S-band fully polarimetric radar systems, a fourteen day repeat period, and a swath width on the order of several hundred kilometers. To address the needs of the science and applications communities that NI-SAR will support, the systems observing strategy is currently being planned such that data rate and the system configuration will address the needs of the community. In this presentation, a description of the NI-SAR system will be given along with the currently planned observing strategy and derived products that will be relevant to the overall GEOGLAM initiative.

Airborne precursor missions in support of SIR-C/X-SAR

NASA Technical Reports Server (NTRS)

Evans, D.; Oettl, H.; Pampaloni, P.

1991-01-01

The NASA DC-8 and DLR E-SAR airborne imaging radars have been deployed over several sites in Europe and the U.S. in support of SIR-C/X-SAR (Shuttle Imaging Radar-C/X-Synthetic Aperture Radar) science team investigations. To date, data have been acquired in support of studies of alpine glaciers, forests, geology, oceanography, and calibration. An experimental campaign with airborne sensors will take place in Europe in June to July 1991 which will allow multitemporal surveys of several Europeans sites. Current plans are for calibration and ecology experiments to be undertaken in Germany, the Netherlands, Italy, France, and the United Kingdom. Coordinated multitemporal aircraft and ground campaigns are planned in support of hydrology experiments in Italy, the United Kingdom, and Austria. Data will also be acquired in support of oceanogrqhy in the Gulf of Genova, North Atlantic, Straits of Messina and the North Sea. Geology sites will include Campi Flegrei and Vesuvio, Italy.

Applicability of interferometric SAR technology to ground movement and pipeline monitoring

NASA Astrophysics Data System (ADS)

Grivas, Dimitri A.; Bhagvati, Chakravarthy; Schultz, B. C.; Trigg, Alan; Rizkalla, Moness

1998-03-01

This paper summarizes the findings of a cooperative effort between NOVA Gas Transmission Ltd. (NGTL), the Italian Natural Gas Transmission Company (SNAM), and Arista International, Inc., to determine whether current remote sensing technologies can be utilized to monitor small-scale ground movements over vast geographical areas. This topic is of interest due to the potential for small ground movements to cause strain accumulation in buried pipeline facilities. Ground movements are difficult to monitor continuously, but their cumulative effect over time can have a significant impact on the safety of buried pipelines. Interferometric synthetic aperture radar (InSAR or SARI) is identified as the most promising technique of those considered. InSAR analysis involves combining multiple images from consecutive passes of a radar imaging platform. The resulting composite image can detect changes as small as 2.5 to 5.0 centimeters (based on current analysis methods and radar satellite data of 5 centimeter wavelength). Research currently in progress shows potential for measuring ground movements as small as a few millimeters. Data needed for InSAR analysis is currently commercially available from four satellites, and additional satellites are planned for launch in the near future. A major conclusion of the present study is that InSAR technology is potentially useful for pipeline integrity monitoring. A pilot project is planned to test operational issues.

Generation of Classical DInSAR and PSI Ground Motion Maps on a Cloud Thematic Platform

NASA Astrophysics Data System (ADS)

Mora, Oscar; Ordoqui, Patrick; Romero, Laia

2016-08-01

This paper presents the experience of ALTAMIRA INFORMATION uploading InSAR (Synthetic Aperture Radar Interferometry) services in the Geohazard Exploitation Platform (GEP), supported by ESA. Two different processing chains are presented jointly with ground motion maps obtained from the cloud computing, one being DIAPASON for classical DInSAR and SPN (Stable Point Network) for PSI (Persistent Scatterer Interferometry) processing. The product obtained from DIAPASON is the interferometric phase related to ground motion (phase fringes from a SAR pair). SPN provides motion data (mean velocity and time series) on high-quality pixels from a stack of SAR images. DIAPASON is already implemented, and SPN is under development to be exploited with historical data coming from ERS-1/2 and ENVISAT satellites, and current acquisitions of SENTINEL-1 in SLC and TOPSAR modes.

A GeoNode-Based Multiscale Platform For Management, Visualization And Integration Of DInSAR Data With Different Geospatial Information Sources

NASA Astrophysics Data System (ADS)

Buonanno, Sabatino; Fusco, Adele; Zeni, Giovanni; Manunta, Michele; Lanari, Riccardo

2017-04-01

This work describes the implementation of an efficient system for managing, viewing, analyzing and updating remotely sensed data, with special reference to Differential Interferometric Synthetic Aperture Radar (DInSAR) data. The DInSAR products measure Earth surface deformation both in space and time, producing deformation maps and time series[1,2]. The use of these data in research or operational contexts requires tools that have to handle temporal and spatial variability with high efficiency. For this aim we present an implementation based on Spatial Data Infrastructure (SDI) for data integration, management and interchange, by using standard protocols[3]. SDI tools provide access to static datasets that operate only with spatial variability . In this paper we use the open source project GeoNode as framework to extend SDI infrastructure functionalities to ingest very efficiently DInSAR deformation maps and deformation time series. GeoNode allows to realize comprehensive and distributed infrastructure, following the standards of the Open Geospatial Consortium, Inc. - OGC, for remote sensing data management, analysis and integration [4,5]. In the current paper we explain the methodology used for manage the data complexity and data integration using the opens source project GeoNode. The solution presented in this work for the ingestion of DinSAR products is a very promising starting point for future developments of the OGC compliant implementation of a semi-automatic remote sensing data processing chain . [1] Berardino, P., Fornaro, G., Lanari, R., & Sansosti, E. (2002). A new Algorithm for Surface Deformation Monitoring based on Small Baseline Differential SAR Interferograms. IEEE Transactions on Geoscience and Remote Sensing, 40, 11, pp. 2375-2383. [2] Lanari R., F. Casu, M. Manzo, G. Zeni,, P. Berardino, M. Manunta and A. Pepe (2007), An overview of the Small Baseline Subset Algorithm: a DInSAR Technique for Surface Deformation Analysis, P. Appl. Geophys., 164, doi: 10.1007/s00024-007-0192-9. [3] Nebert, D.D. (ed). 2000. Developing Spatial data Infrastructures: The SDI Cookbook. [4] Geonode (www.geonode.org) [5] Kolodziej, k. (ed). 2004. OGC OpenGIS Web Map Server Cookbook. Open Geospatial Consortium, 1.0.2 edition.

Onboard Interferometric SAR Processor for the Ka-Band Radar Interferometer (KaRIn)

NASA Technical Reports Server (NTRS)

Esteban-Fernandez, Daniel; Rodriquez, Ernesto; Peral, Eva; Clark, Duane I.; Wu, Xiaoqing

2011-01-01

An interferometric synthetic aperture radar (SAR) onboard processor concept and algorithm has been developed for the Ka-band radar interferometer (KaRIn) instrument on the Surface and Ocean Topography (SWOT) mission. This is a mission- critical subsystem that will perform interferometric SAR processing and multi-look averaging over the oceans to decrease the data rate by three orders of magnitude, and therefore enable the downlink of the radar data to the ground. The onboard processor performs demodulation, range compression, coregistration, and re-sampling, and forms nine azimuth squinted beams. For each of them, an interferogram is generated, including common-band spectral filtering to improve correlation, followed by averaging to the final 1 1-km ground resolution pixel. The onboard processor has been prototyped on a custom FPGA-based cPCI board, which will be part of the radar s digital subsystem. The level of complexity of this technology, dictated by the implementation of interferometric SAR processing at high resolution, the extremely tight level of accuracy required, and its implementation on FPGAs are unprecedented at the time of this reporting for an onboard processor for flight applications.

Implementation of RF Circuitry for Real-Time Digital Beam-Forming SAR Calibration Schemes

NASA Technical Reports Server (NTRS)

Horst, Stephen J.; Hoffman, James P.; Perkovic-Martin, Dragana; Shaffer, Scott; Thrivikraman, Tushar; Yates, Phil; Veilleux, Louise

2012-01-01

The SweepSAR architecture for space-borne remote sensing applications is an enabling technology for reducing the temporal baseline of repeat-pass interferometers while maintaining near-global coverage. As part of this architecture, real-time digital beam-forming would be performed on the radar return signals across multiple channels. Preserving the accuracy of the combined return data requires real-time calibration of the transmit and receive RF paths on each channel. This paper covers several of the design considerations necessary to produce a practical implementation of this concept.

A double epidemic model for the SARS propagation

PubMed Central

Ng, Tuen Wai; Turinici, Gabriel; Danchin, Antoine

2003-01-01

Background An epidemic of a Severe Acute Respiratory Syndrome (SARS) caused by a new coronavirus has spread from the Guangdong province to the rest of China and to the world, with a puzzling contagion behavior. It is important both for predicting the future of the present outbreak and for implementing effective prophylactic measures, to identify the causes of this behavior. Results In this report, we show first that the standard Susceptible-Infected-Removed (SIR) model cannot account for the patterns observed in various regions where the disease spread. We develop a model involving two superimposed epidemics to study the recent spread of the SARS in Hong Kong and in the region. We explore the situation where these epidemics may be caused either by a virus and one or several mutants that changed its tropism, or by two unrelated viruses. This has important consequences for the future: the innocuous epidemic might still be there and generate, from time to time, variants that would have properties similar to those of SARS. Conclusion We find that, in order to reconcile the existing data and the spread of the disease, it is convenient to suggest that a first milder outbreak protected against the SARS. Regions that had not seen the first epidemic, or that were affected simultaneously with the SARS suffered much more, with a very high percentage of persons affected. We also find regions where the data appear to be inconsistent, suggesting that they are incomplete or do not reflect an appropriate identification of SARS patients. Finally, we could, within the framework of the model, fix limits to the future development of the epidemic, allowing us to identify landmarks that may be useful to set up a monitoring system to follow the evolution of the epidemic. The model also suggests that there might exist a SARS precursor in a large reservoir, prompting for implementation of precautionary measures when the weather cools down. PMID:12964944

CryoSat SAR/SARin Level1b products: assessment of BaselineC and improvements towards BaselineD

NASA Astrophysics Data System (ADS)

Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso

2017-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. Cryosat carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach a significantly improved along track resolution with respect to traditional pulse-width limited altimeters. CryoSat is the first altimetry mission operating in SAR mode and continuous improvements in the Level1 Instrument Processing Facility (IPF1) are being identified, tested and validated in order to improve the quality of the Level1b products. The current IPF, Baseline C, was released in operation in April 2015 and the second CryoSat reprocessing campaign was jointly initiated, taking benefit of the upgrade implemented in the IPF1 processing chain but also of some specific configurations for the calibration corrections. In particular, the CryoSat Level1b BaselineC products generated in the framework of the second reprocessing campaign include refined information for what concerns the mispointing angles and the calibration corrections. This poster will thus detail thus the evolutions that are currently planned for the CryoSat BaselineD SAR/SARin Level1b products and the corresponding quality improvements that are expected.

Error Analysis and Validation for Insar Height Measurement Induced by Slant Range

NASA Astrophysics Data System (ADS)

Zhang, X.; Li, T.; Fan, W.; Geng, X.

2018-04-01

InSAR technique is an important method for large area DEM extraction. Several factors have significant influence on the accuracy of height measurement. In this research, the effect of slant range measurement for InSAR height measurement was analysis and discussed. Based on the theory of InSAR height measurement, the error propagation model was derived assuming no coupling among different factors, which directly characterise the relationship between slant range error and height measurement error. Then the theoretical-based analysis in combination with TanDEM-X parameters was implemented to quantitatively evaluate the influence of slant range error to height measurement. In addition, the simulation validation of InSAR error model induced by slant range was performed on the basis of SRTM DEM and TanDEM-X parameters. The spatial distribution characteristics and error propagation rule of InSAR height measurement were further discussed and evaluated.

Onboard FPGA-based SAR processing for future spaceborne systems

NASA Technical Reports Server (NTRS)

Le, Charles; Chan, Samuel; Cheng, Frank; Fang, Winston; Fischman, Mark; Hensley, Scott; Johnson, Robert; Jourdan, Michael; Marina, Miguel; Parham, Bruce;

75 FR 79947 - Privacy Act of 1974: Implementation of Exemptions; Department of Homeland Security/ALL-031...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-21

...-SARs database will include or exclude ISE-SARs filed pursuant to the BSA and Anti-Money Laundering... enforcement officials in the areas of cybersecurity, fraud, and money laundering. The financial services... Initiative System of Records'' from one or more provisions of the Privacy Act because of criminal, civil, and...

Standards for space automation and robotics

NASA Technical Reports Server (NTRS)

Kader, Jac B.; Loftin, R. B.

1992-01-01

The AIAA's Committee on Standards for Space Automation and Robotics (COS/SAR) is charged with the identification of key functions and critical technologies applicable to multiple missions that reflect fundamental consideration of environmental factors. COS/SAR's standards/practices/guidelines implementation methods will be based on reliability, performance, and operations, as well as economic viability and life-cycle costs, simplicity, and modularity.

Implementation of integrated circuit and design of SAR ADC for fully implantable hearing aids.

PubMed

Kim, Jong Hoon; Lee, Jyung Hyun; Cho, Jin-Ho

2017-07-20

The hearing impaired population has been increasing; many people suffer from hearing problems. To deal with this difficulty, various types of hearing aids are being rapidly developed. In particular, fully implantable hearing aids are being actively studied to improve the performance of existing hearing aids and to reduce the stigma of hearing loss patients. It has to be of small size and low-power consumption for easy implantation and long-term use. The objective of the study was to implement a small size and low-power consumption successive approximation register analog-to-digital converter (SAR ADC) for fully implantable hearing aids. The ADC was selected as the SAR ADC because its analog circuit components are less required by the feedback circuit of the SAR ADC than the sigma-delta ADC which is conventionally used in hearing aids, and it has advantages in the area and power consumption. So, the circuit of SAR ADC is designed considering the speech region of humans because the objective is to deliver the speech signals of humans to hearing loss patients. If the switch of sample and hold works in the on/off positions, the charge injection and clock feedthrough are produced by a parasitic capacitor. These problems affect the linearity of the hold voltage, and as a result, an error of the bit conversion is generated. In order to solve the problem, a CMOS switch that consists of NMOS and PMOS was used, and it reduces the charge injection because the charge carriers in the NMOS and PMOS have inversed polarity. So, 16 bit conversion is performed before the occurrence of the Least Significant Bit (LSB) error. In order to minimize the offset voltage and power consumption of the designed comparator, we designed a preamplifier with current mirror. Therefore, the power consumption was reduced by the power control switch used in the comparator. The layout of the designed SAR ADC was performed by Virtuoso Layout Editor (Cadence, USA). In the layout result, the size of the designed SAR ADC occupied 124.9 μm × 152.1 μm. The circuit verification was performed by layout versus schematic (LVS) and design rule check (DRC) which are provided by Calibre (Mentor Graphics, USA), and it was confirmed that there was no error. The designed SAR ADC was implemented in SMIC 180 nm CMOS technology. The operation of the manufactured SAR ADC was confirmed by using an oscilloscope. The SAR ADC output was measured using a distortion meter (HM 8027), when applying pure tone sounds of 94 dB SPL at 500, 800, and 1600 Hz regions. As a result, the THD performance of the proposed chip was satisfied with the ANSI. s3. 22. 2003 standard. We proposed a low-power 16-bit 32 kHz SAR ADC for fully implantable hearing aids. The manufactured SAR ADC based on this design was confirmed to have advantages in power consumption and size through the comparison with the conventional ADC. Therefore, the manufactured SAR ADC is expected to be used in the implantable medical device field and speech signal processing field, which require small size and low power consumption.

Spacecraft on-board SAR image generation for EOS-type missions

NASA Technical Reports Server (NTRS)

Liu, K. Y.; Arens, W. E.; Assal, H. M.; Vesecky, J. F.

1987-01-01

Spacecraft on-board synthetic aperture radar (SAR) image generation is an extremely difficult problem because of the requirements for high computational rates (usually on the order of Giga-operations per second), high reliability (some missions last up to 10 years), and low power dissipation and mass (typically less than 500 watts and 100 Kilograms). Recently, a JPL study was performed to assess the feasibility of on-board SAR image generation for EOS-type missions. This paper summarizes the results of that study. Specifically, it proposes a processor architecture using a VLSI time-domain parallel array for azimuth correlation. Using available space qualifiable technology to implement the proposed architecture, an on-board SAR processor having acceptable power and mass characteristics appears feasible for EOS-type applications.

Application of GIS-based models for delineating the UAV flight region to support Search and Rescue activities

NASA Astrophysics Data System (ADS)

Jurecka, Miroslawa; Niedzielski, Tomasz

2017-04-01

The objective of the approach presented in this paper is to demonstrate a potential of using the combination of two GIS-based models - mobility model and ring model - for delineating a region above which an Unmanned Aerial Vehicle (UAV) should fly to support the Search and Rescue (SAR) activities. The procedure is based on two concepts, both describing a possible distance/path that lost person could travel from the initial planning point (being either the point last seen, or point last known). The first approach (the ring model) takes into account the crow's flight distance traveled by a lost person and its probability distribution. The second concept (the mobility model) is based on the estimated travel speed and the associated features of the geographical environment of the search area. In contrast to the ring model covering global (hence more general) SAR perspective, the mobility model represents regional viewpoint by taking into consideration local impedance. Both models working together can serve well as a starting point for the UAV flight planning to strengthen the SAR procedures. We present the method of combining the two above-mentioned models in order to delineate UAVs flight region and increase the Probability of Success for future SAR missions. The procedure is a part of a larger Search and Rescue (SAR) system which is being developed at the University of Wrocław, Poland (research project no. IP2014 032773 financed by the Ministry of Science and Higher Education of Poland). The mobility and ring models have been applied to the Polish territory, and they act in concert to provide the UAV operator with the optimal search region. This is attained in real time so that the UAV-based SAR mission can be initiated quickly.

Ice tracking techniques, implementation, performance, and applications

NASA Technical Reports Server (NTRS)

Rothrock, D. A.; Carsey, F. D.; Curlander, J. C.; Holt, B.; Kwok, R.; Weeks, W. F.

1992-01-01

Present techniques of ice tracking make use both of cross-correlation and of edge tracking, the former being more successful in heavy pack ice, the latter being critical for the broken ice of the pack margins. Algorithms must assume some constraints on the spatial variations of displacements to eliminate fliers, but must avoid introducing any errors into the spatial statistics of the measured displacement field. We draw our illustrations from the implementation of an automated tracking system for kinematic analyses of ERS-1 and JERS-1 SAR imagery at the University of Alaska - the Alaska SAR Facility's Geophysical Processor System. Analyses of the ice kinematic data that might have some general interest to analysts of cloud-derived wind fields are the spatial structure of the fields, and the evaluation and variability of average deformation and its invariants: divergence, vorticity and shear. Many problems in sea ice dynamics and mechanics can be addressed with the kinematic data from SAR.

The integration of Human Factors (HF) in the SAR process training course text

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryan, T.G.

1995-03-01

This text provides the technical basis for a two-day course on human factors (HF), as applied to the Safety Analysis Report (SAR) process. The overall objective of this text and course is to: provide the participant with a working knowledge of human factors-related requirements, suggestions for doing a human safety analysis applying a graded approach, and an ability to demonstrate using the results of the human safety analysis, that human factors elements as defined by DOE (human factors engineering, procedures, training, oversight, staffing, qualifications), can support wherever necessary, nuclear safety commitments in the SAR. More specifically, the objectives of themore » text and course are: (1) To provide the SAR preparer with general guidelines for doing HE within the context of a graded approach for the SAR; (2) To sensitize DOE facility managers and staff, safety analysts and SAR preparers, independent reviewers, and DOE reviewers and regulators, to DOE Order 5480.23 requirements for HE in the SAR; (3) To provide managers, analysts, reviewers and regulators with a working knowledge of HE concepts and techniques within the context of a graded approach for the SAR, and (4) To provide SAR managers and DOE reviewers and regulators with general guidelines for monitoring and coordinating the work of preparers of HE inputs throughout the SAR process, and for making decisions regarding the safety relevance of HE inputs to the SAR. As a ready reference for implementing the human factors requirements of DOE Order 5480.22 and DOE Standard 3009-94, this course text and accompanying two-day course are intended for all persons who are involved in the SAR.« less

Correcting Spatial Variance of RCM for GEO SAR Imaging Based on Time-Frequency Scaling.

PubMed

Yu, Ze; Lin, Peng; Xiao, Peng; Kang, Lihong; Li, Chunsheng

2016-07-14

Compared with low-Earth orbit synthetic aperture radar (SAR), a geosynchronous (GEO) SAR can have a shorter revisit period and vaster coverage. However, relative motion between this SAR and targets is more complicated, which makes range cell migration (RCM) spatially variant along both range and azimuth. As a result, efficient and precise imaging becomes difficult. This paper analyzes and models spatial variance for GEO SAR in the time and frequency domains. A novel algorithm for GEO SAR imaging with a resolution of 2 m in both the ground cross-range and range directions is proposed, which is composed of five steps. The first is to eliminate linear azimuth variance through the first azimuth time scaling. The second is to achieve RCM correction and range compression. The third is to correct residual azimuth variance by the second azimuth time-frequency scaling. The fourth and final steps are to accomplish azimuth focusing and correct geometric distortion. The most important innovation of this algorithm is implementation of the time-frequency scaling to correct high-order azimuth variance. As demonstrated by simulation results, this algorithm can accomplish GEO SAR imaging with good and uniform imaging quality over the entire swath.

Correcting Spatial Variance of RCM for GEO SAR Imaging Based on Time-Frequency Scaling

PubMed Central

Yu, Ze; Lin, Peng; Xiao, Peng; Kang, Lihong; Li, Chunsheng

2016-01-01

Compared with low-Earth orbit synthetic aperture radar (SAR), a geosynchronous (GEO) SAR can have a shorter revisit period and vaster coverage. However, relative motion between this SAR and targets is more complicated, which makes range cell migration (RCM) spatially variant along both range and azimuth. As a result, efficient and precise imaging becomes difficult. This paper analyzes and models spatial variance for GEO SAR in the time and frequency domains. A novel algorithm for GEO SAR imaging with a resolution of 2 m in both the ground cross-range and range directions is proposed, which is composed of five steps. The first is to eliminate linear azimuth variance through the first azimuth time scaling. The second is to achieve RCM correction and range compression. The third is to correct residual azimuth variance by the second azimuth time-frequency scaling. The fourth and final steps are to accomplish azimuth focusing and correct geometric distortion. The most important innovation of this algorithm is implementation of the time-frequency scaling to correct high-order azimuth variance. As demonstrated by simulation results, this algorithm can accomplish GEO SAR imaging with good and uniform imaging quality over the entire swath. PMID:27428974

Fusion of Cross-Track TerraSAR-X PS Point Clouds over Las Vegas

NASA Astrophysics Data System (ADS)

Wang, Ziyun; Balz, Timo; Wei, Lianhuan; Liao, Mingsheng

2014-11-01

Persistent scatterer interferometry (PS-InSAR) is widely used in radar remote sensing. However, because the surface motion is estimated in the line-of-sight (LOS) direction, it is not possible to differentiate between vertical and horizontal surface motions from a single stack. Cross-track data, i.e. the combination of data from ascending and descending orbits, allows us to better analyze the deformation and to obtain 3d motion information. We implemented a cross-track fusion of PS-InSAR point cloud data, making it possible to separate the vertical and horizontal components of the surface motion.

Alaska SAR Facility (ASF5) SAR Communications (SARCOM) Data Compression System

NASA Technical Reports Server (NTRS)

Mango, Stephen A.

1989-01-01

The real-time operational requirements for SARCOM translation into a high speed image data handler and processor to achieve the desired compression ratios and the selection of a suitable image data compression technique with as low as possible fidelity (information) losses and which can be implemented in an algorithm placing a relatively low arithmetic load on the system are described.

Applying a particle filtering technique for canola crop growth stage estimation in Canada

NASA Astrophysics Data System (ADS)

Sinha, Abhijit; Tan, Weikai; Li, Yifeng; McNairn, Heather; Jiao, Xianfeng; Hosseini, Mehdi

2017-10-01

Accurate crop growth stage estimation is important in precision agriculture as it facilitates improved crop management, pest and disease mitigation and resource planning. Earth observation imagery, specifically Synthetic Aperture Radar (SAR) data, can provide field level growth estimates while covering regional scales. In this paper, RADARSAT-2 quad polarization and TerraSAR-X dual polarization SAR data and ground truth growth stage data are used to model the influence of canola growth stages on SAR imagery extracted parameters. The details of the growth stage modeling work are provided, including a) the development of a new crop growth stage indicator that is continuous and suitable as the state variable in the dynamic estimation procedure; b) a selection procedure for SAR polarimetric parameters that is sensitive to both linear and nonlinear dependency between variables; and c) procedures for compensation of SAR polarimetric parameters for different beam modes. The data was collected over three crop growth seasons in Manitoba, Canada, and the growth model provides the foundation of a novel dynamic filtering framework for real-time estimation of canola growth stages using the multi-sensor and multi-mode SAR data. A description of the dynamic filtering framework that uses particle filter as the estimator is also provided in this paper.

TanDEM-X calibrated Raw DEM generation

NASA Astrophysics Data System (ADS)

Rossi, Cristian; Rodriguez Gonzalez, Fernando; Fritz, Thomas; Yague-Martinez, Nestor; Eineder, Michael

2012-09-01

The TanDEM-X mission successfully started on June 21st 2010 with the launch of the German radar satellite TDX, placed in orbit in close formation with the TerraSAR-X (TSX) satellite, and establishing the first spaceborne bistatic interferometer. The processing of SAR raw data to the Raw DEM is performed by one single processor, the Integrated TanDEM-X Processor (ITP). The quality of the Raw DEM is a fundamental parameter for the mission planning. In this paper, a novel quality indicator is derived. It is based on the comparison of the interferometric measure, the unwrapped phase, and the stereo-radargrammetric measure, the geometrical shifts computed in the coregistration stage. By stating the accuracy of the unwrapped phase, it constitutes a useful parameter for the determination of problematic scenes, which will be resubmitted to the dual baseline phase unwrapping processing chain for the mitigation of phase unwrapping errors. The stereo-radargrammetric measure is also operationally used for the Raw DEM absolute calibration through an accurate estimation of the absolute phase offset. This paper examines the interferometric algorithms implemented for the operational TanDEM-X Raw DEM generation, focusing particularly on its quality assessment and its calibration.

The SIR-B science investigations plan

NASA Technical Reports Server (NTRS)

1984-01-01

Shuttle Imaging Radar-B (SIR-B) is the second synthetic aperture radar (SAR) to be flown on the National Aeronautics and Space Administration's Space Transportation System (Shuttle). It is the first spaceborne SAR to feature an antenna that allows acquisition of multiincidence angle imagery. An international team of scientists will use SIR-B to conduct investigations in a wide range of disciplines. The radar, the mission, and the investigations are described.

Including the public in pandemic planning: a deliberative approach

PubMed Central

2010-01-01

Background Against a background of pandemic threat posed by SARS and avian H5N1 influenza, this study used deliberative forums to elucidate informed community perspectives on aspects of pandemic planning. Methods Two deliberative forums were carried out with members of the South Australian community. The forums were supported by a qualitative study with adults and youths, systematic reviews of the literature and the involvement of an extended group of academic experts and policy makers. The forum discussions were recorded with simultaneous transcription and analysed thematically. Results Participants allocated scarce resources of antiviral drugs and pandemic vaccine based on a desire to preserve society function in a time of crisis. Participants were divided on the acceptability of social distancing and quarantine measures. However, should such measures be adopted, they thought that reasonable financial, household and psychological support was essential. In addition, provided such support was present, the participants, in general, were willing to impose strict sanctions on those who violated quarantine and social distancing measures. Conclusions The recommendations from the forums suggest that the implementation of pandemic plans in a severe pandemic will be challenging, but not impossible. Implementation may be more successful if the public is engaged in pandemic planning before a pandemic, effective communication of key points is practiced before and during a pandemic and if judicious use is made of supportive measures to assist those in quarantine or affected by social isolation measures. PMID:20718996

The InSAR Scientific Computing Environment (ISCE): An Earth Science SAR Processing Framework, Toolbox, and Foundry

NASA Astrophysics Data System (ADS)

Agram, P. S.; Gurrola, E. M.; Lavalle, M.; Sacco, G. F.; Rosen, P. A.

2016-12-01

The InSAR Scientific Computing Environment (ISCE) provides both a modular, flexible, and extensible framework for building software components and applications that work together seamlessly as well as a toolbox for processing InSAR data into higher level geodetic image products from a diverse array of radar satellites and aircraft. ISCE easily scales to serve as the SAR processing engine at the core of the NASA JPL Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards as well as a software toolbox for individual scientists working with SAR data. ISCE is planned as the foundational element in processing NISAR data, enabling a new class of analyses that take greater advantage of the long time and large spatial scales of these data. ISCE in ARIA is also a SAR Foundry for development of new processing components and workflows to meet the needs of both large processing centers and individual users. The ISCE framework contains object-oriented Python components layered to construct Python InSAR components that manage legacy Fortran/C InSAR programs. The Python user interface enables both command-line deployment of workflows as well as an interactive "sand box" (the Python interpreter) where scientists can "play" with the data. Recent developments in ISCE include the addition of components to ingest Sentinel-1A SAR data (both stripmap and TOPS-mode) and a new workflow for processing the TOPS-mode data. New components are being developed to exploit polarimetric-SAR data to provide the ecosystem and land-cover/land-use change communities with rigorous and efficient tools to perform multi-temporal, polarimetric and tomographic analyses in order to generate calibrated, geocoded and mosaicked Level-2 and Level-3 products (e.g., maps of above-ground biomass or forest disturbance). ISCE has been downloaded by over 200 users by a license for WinSAR members through the Unavco.org website. Others may apply directly to JPL for a license at download.jpl.nasa.gov.

Sentinel-1 Mission Overview and Implementation Status

NASA Astrophysics Data System (ADS)

Davidson, M.; Attema, E.; Snoeij, P.; Levrini, G.

2009-04-01

Sentinel-1 is an imaging radar mission at C-band consisting of a constellation of two satellites aimed at providing continuity of all-weather day-and-night supply of imagery for user services. Special emphasis is placed on services identified in ESA's GMES service elements program and on projects funded by the European Union Framework Programmes. Three priorities (fast-track services) for the mission have been identified by user consultation working groups of the European Union: Marine Core Services, Land Monitoring and Emergency Services. These cover applications such as: - Monitoring sea ice zones and the arctic environment - Surveillance of marine environment - Monitoring land surface motion risks - Mapping of land surfaces: forest, water and soil, agriculture - Mapping in support of humanitarian aid in crisis situations. The Sentinel 1 space segment will be designed and built by an industrial consortium with Thales Alenia Space Italia as prime contractor and EADS Astrium GmbH as C-SAR instrument responsible. Data products from current and previous ESA missions including ERS-1, ERS-2 and Envisat missions form the basis for many of the pilot GMES services. Consequently Sentinel-1 data maintain data quality levels of the Agency‘s previous SAR missions in terms of spatial resolution, sensitivity, accuracy, polarization and wavelength. Nonetheless, the Sentinel-1 synthetic aperture radar (SAR) constellation represents a completely new approach to SAR mission design by ESA in direct response to the operational needs for SAR data expressed under the EU-ESA Global Monitoring for Environment and Security (GMES) programme. The Sentinel-1 constellation is expected to provide near daily coverage over Europe and Canada, global coverage all independent of weather with delivery of radar data within 1 hour of acquisition - all vast improvements with respect to the existing SAR systems. The continuity of C-band SAR data combined with the greatly improved data provision is expected not only to support the existing key operational services but will also support the evolving user community both for operational and remote sensing science applications. The Sentinel-1 satellite carries a Synthetic Aperture Radar (SAR) instrument with four standard operational modes: Strip Map Mode, Interferometric Wide Swath Mode, Extra-wide Swath Mode and Wave Mode. Some of their important characteristics are listed below. MODE ACCESS ANGLE (DEG.) SINGLE LOOK RESOLUTION RANGE X AZIMUTH SWATH WIDTH POLARISATION STRIP MAP 20-45 5 X 5 M > 80 KM HH+HV OR VV+VH INTERFEROMETRIC WIDE SWATH > 25 5 X 20 M > 250 KM HH+HV OR VV+VH EXTRA WIDE SWATH > 20 20 X 40 M > 400 KM HH+HV OR VV+VH WAVE MODE 23 AND 36.5 20 X 5 M > 20 X 20 KM VIGNETTES AT 100 KM INTERVALS HH OR VV FOR ALL MODES RADIOMETRIC ACCURACY (3 Σ) 1 DB NOISE EQUIVALENT SIGMA ZERO -22 DB POINT TARGET AMBIGUITY RATIO -25 DB DISTRIBUTED TARGET AMBIGUITY RATIO -22 DB It is expected that Sentinel-1 be launched in 2011. Once in orbit Sentinel-1 will be operated from two centres on the ground. The Agency‘s facilities in Darmstadt, Germany will command the satellite ensuring its proper functioning along the orbit. The mission exploitation will be managed at the Agency‘s facilities in Frascati, Italy, including the planning of the acquisitions by the SAR instrument according to the mission requirements, the processing of the acquired data and the provision of the resulting products to the users. he presentation will provide an overview of the Sentinel-1 mission, the user requirements driving the mission, the status and characteristics of the technical implementation. The key elements of the mission supporting the evolving needs of the user community both in operational and remote sensing science applications will be highlighted.

e-Collaboration for Earth observation (E-CEO): the Cloud4SAR interferometry data challenge

NASA Astrophysics Data System (ADS)

Casu, Francesco; Manunta, Michele; Boissier, Enguerran; Brito, Fabrice; Aas, Christina; Lavender, Samantha; Ribeiro, Rita; Farres, Jordi

2014-05-01

The e-Collaboration for Earth Observation (E-CEO) project addresses the technologies and architectures needed to provide a collaborative research Platform for automating data mining and processing, and information extraction experiments. The Platform serves for the implementation of Data Challenge Contests focusing on Information Extraction for Earth Observations (EO) applications. The possibility to implement multiple processors within a Common Software Environment facilitates the validation, evaluation and transparent peer comparison among different methodologies, which is one of the main requirements rose by scientists who develop algorithms in the EO field. In this scenario, we set up a Data Challenge, referred to as Cloud4SAR (http://wiki.services.eoportal.org/tiki-index.php?page=ECEO), to foster the deployment of Interferometric SAR (InSAR) processing chains within a Cloud Computing platform. While a large variety of InSAR processing software tools are available, they require a high level of expertise and a complex user interaction to be effectively run. Computing a co-seismic interferogram or a 20-years deformation time series on a volcanic area are not easy tasks to be performed in a fully unsupervised way and/or in very short time (hours or less). Benefiting from ESA's E-CEO platform, participants can optimise algorithms on a Virtual Sandbox environment without being expert programmers, and compute results on high performing Cloud platforms. Cloud4SAR requires solving a relatively easy InSAR problem by trying to maximize the exploitation of the processing capabilities provided by a Cloud Computing infrastructure. The proposed challenge offers two different frameworks, each dedicated to participants with different skills, identified as Beginners and Experts. For both of them, the contest mainly resides in the degree of automation of the deployed algorithms, no matter which one is used, as well as in the capability of taking effective benefit from a parallel computing environment.

UNAVCO Data Center Initiatives in CyberInfrastructure for Discovery, Services, and Distribution of Data and Products

NASA Astrophysics Data System (ADS)

Boler, F.; Meertens, C.

2012-04-01

The UNAVCO Data Center in Boulder, Colorado, archives for preservation and distributes geodesy data and products in the GNSS, InSAR, and LiDAR domains to the scientific and education community. The GNSS data, which in addition to geodesy are useful for tectonic, volcanologic, ice mass, glacial isostatic adjustment, meteorological and other studies, come from 2,500 continuously operating stations and 8000 survey-mode observation points around the globe that are operated by over 100 U.S. and international members of the UNAVCO consortium. SAR data, which are in many ways complementary to the GNSS data collection have been acquired in concert with the WInSAR Consortium activities and with EarthScope, with a focus on the western United States. UNAVCO also holds a growing collection of terrestrial laser scanning data. Several partner US geodesy data centers, along with UNAVCO, have developed and are in the process of implementing the Geodesy Seamless Archive Centers, a web services based technology to facilitate the exchange of metadata and delivery of data and products to users. These services utilize a repository layer implemented at each data center, and a service layer to identify and present any data center-specific services and capabilities, allowing simplified vertical federation of metadata from independent data centers. UNAVCO also has built web services for SAR data discovery and delivery, and will partner with other SAR data centers and institutions to provide access for the InSAR scientist to SAR data and ancillary data sets, web services to produce interferograms, and mechanisms to archive and distribute resulting higher level products. Improved access to LiDAR data from space-based, airborne, and terrestrial platforms through utilization of web services is similarly currently under development. These efforts in cyberinfrastructure, while initially aimed at intra-domain data sharing and providing products for research and education, are envisioned as potentially serving as the basis for leveraging integrated access across a broad set of Earth science domains.

The SIR-B science plan

NASA Technical Reports Server (NTRS)

1982-01-01

The Shuttle Imaging Radar-B (SIR-B) will be the third in a series of spaceborne SAR experiments conducted by NASA which began with the 1978 launch of SEASAT and continued with the 1981 launch of SIR-A. Like SEASAT and SIR-A, SIR-B will operate at L-band and will be horizontally polarized. However, SIR-B will allow digitally processed imagery to be acquired at selectable incidence angles between 15 and 60 deg, thereby permitting, for the first time, parametric studies of the effect of illumination geometry on SAR image information extraction. This document presents a science plan for SIR-B and serves as a reference for the types of geoscientific, sensor, and processing experiments which are possible.

Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches.

PubMed

Hong, Seon-Eui; Lee, Ae-Kyoung; Kwon, Jong-Hwa; Pack, Jeong-Ki

2016-10-07

In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.

Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches

NASA Astrophysics Data System (ADS)

Hong, Seon-Eui; Lee, Ae-Kyoung; Kwon, Jong-Hwa; Pack, Jeong-Ki

2016-10-01

In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.

Seroprevalence of SARS coronavirus antibody in household contacts.

PubMed Central

Lee, C-C; Chen, S-Y; Chang, I-J; Tsai, P-C; Lu, T-C; Wu, P-L; Chen, W-J; Huang, L-M; Chang, S-C

2005-01-01

Between March and July 2003, 671 cases of severe acute respiratory syndrome (SARS) were diagnosed in Taiwan with a total of 84 fatalities. After the epidemic, a serological survey was conducted involving the asymptomatic household contacts. Household contacts of 13 index patients were enrolled in the study. Contact history and clinical symptoms of the household contacts were recorded by standardized questionnaires. Blood samples of patients and household contacts were collected at least 28 days after symptom onset in the index patients or household exposure in the contacts for SARS-associated coronavirus (SARS-CoV) IgG testing. On the basis of this investigation, 29 persons (25 adults and 4 children) were identified as having had unprotected exposure to the index cases before infection-control practices were implemented. Laboratory evaluation of clinical specimens showed no evidence of transmission of SARS-CoV infection to any contacts. This investigation demonstrated that subclinical transmission among household contacts was low in the described setting. PMID:16274510

A Novel Strategy of Ambiguity Correction for the Improved Faraday Rotation Estimator in Linearly Full-Polarimetric SAR Data.

PubMed

Li, Jinhui; Ji, Yifei; Zhang, Yongsheng; Zhang, Qilei; Huang, Haifeng; Dong, Zhen

2018-04-10

Spaceborne synthetic aperture radar (SAR) missions operating at low frequencies, such as L-band or P-band, are significantly influenced by the ionosphere. As one of the serious ionosphere effects, Faraday rotation (FR) is a remarkable distortion source for the polarimetric SAR (PolSAR) application. Various published FR estimators along with an improved one have been introduced to solve this issue, all of which are implemented by processing a set of PolSAR real data. The improved estimator exhibits optimal robustness based on performance analysis, especially in term of the system noise. However, all published estimators, including the improved estimator, suffer from a potential FR angle (FRA) ambiguity. A novel strategy of the ambiguity correction for those FR estimators is proposed and shown as a flow process, which is divided into pixel-level and image-level correction. The former is not yet recognized and thus is considered in particular. Finally, the validation experiments show a prominent performance of the proposed strategy.

Synergy of Optical and SAR Data for Mapping and Monitoring Mangroves

NASA Astrophysics Data System (ADS)

Monzon, A. K.; Reyes, S. R.; Veridiano, R. K.; Tumaneng, R.; De Alban, J. D.

2016-06-01

Quantitative information on mangrove cover extents is essential in producing relevant resource management plans and conservation strategies. In the Philippines, mangrove rehabilitation was made a priority in relation to disaster risk response and mitigation following the calamities in the coastal communities during typhoon Haiyan/Yolanda; hence, baseline information on the extent of remaining mangrove cover was essential for effective site interventions. Although mangrove cover maps for the country already exists, analysis of mangrove cover changes were limited to the application of fixed annual deforestation rates due to the challenge of acquiring consistent temporal cloud-free optical satellite data over large landscapes. This study presents an initial analysis of SAR and optical imagery combined with field-based observations for detecting mangrove cover extent and changes through a straightforward graphical approach. The analysis is part of a larger study evaluating the synergistic use of time-series L-band SAR and optical data for mapping and monitoring of mangroves. Image segmentation was implemented on the 25-meter ALOS/PALSAR image mosaics, in which the generated objects were subjected to statistical analysis using the software R. In combination with selected Landsat bands, the class statistics from the image bands were used to generate decision trees and thresholds for the hierarchical image classification. The results were compared with global mangrove cover dataset and validated using collected ground truth data. This study developed an integrated replicable approach for analyzing future radar and optical datasets, essential in national level mangrove cover change monitoring and assessment for long-term conservation targets and strategies.

A 21st Century National Public Health System

DTIC Science & Technology

2008-09-01

Security (DHS) released fifteen national planning scenarios in 2004 and the Target Capabilities List: A Companion to the National Preparedness Goal in...no clinical samples available from the first SARS patient in China to test for the virus; however, the second identified SARS case was a chef , Huang...Xingchu, who worked at a restaurant and was reported to have atypical pneumonia. As a chef , he came into regular contact with several types of

Using Narrative to Understand the Convergence of Distance and Campus-Based Learning during the Time of SARS in Hong Kong

ERIC Educational Resources Information Center

McNaught, Carmel

2004-01-01

This paper is a narrative about the use of narrative as a means to understand how the use of technology assisted the educational community of Hong Kong during the SARS crisis of 2003. It is not a carefully planned conventional research study. It is based on seven narratives written by staff at The Chinese University of Hong Kong about their…

Computational efficient unsupervised coastline detection from single-polarization 1-look SAR images of complex coastal environments

NASA Astrophysics Data System (ADS)

Garzelli, Andrea; Zoppetti, Claudia; Pinelli, Gianpaolo

2017-10-01

Coastline detection in synthetic aperture radar (SAR) images is crucial in many application fields, from coastal erosion monitoring to navigation, from damage assessment to security planning for port facilities. The backscattering difference between land and sea is not always documented in SAR imagery, due to the severe speckle noise, especially in 1-look data with high spatial resolution, high sea state, or complex coastal environments. This paper presents an unsupervised, computationally efficient solution to extract the coastline acquired by only one single-polarization 1-look SAR image. Extensive tests on Spotlight COSMO-SkyMed images of complex coastal environments and objective assessment demonstrate the validity of the proposed procedure which is compared to state-of-the-art methods through visual results and with an objective evaluation of the distance between the detected and the true coastline provided by regional authorities.

SweepSAR: Beam-forming on Receive Using a Reflector-Phased Array Feed Combination for Spaceborne SAR

NASA Technical Reports Server (NTRS)

Freeman, A.; Krieger, G.; Rosen, P.; Younis, M.; Johnson, W. T. K.; Huber, S.; Jordan, R.; Moreira, A.

2012-01-01

In this paper, an alternative approach is described that is suited for longer wavelength SARs in particular, employing a large, deployable reflector antenna and a much simpler phased array feed. To illuminate a wide swath, a substantial fraction of the phased array feed is excited on transmit to sub-illuminate the reflector. Shorter transmit pulses are required than for conventional SAR. On receive, a much smaller portion of the phased array feed is used to collect the return echo, so that a greater portion of the reflector antenna area is used. The locus of the portion of the phased array used on receive is adjusted using an analog beam steering network, to 'sweep' the receive beam(s) across the illuminated swath, tracking the return echo. This is similar in some respects to the whiskbroom approach to optical sensors, hence the name: SweepSAR.SweepSAR has advantages over conventional SAR in that it requires less transmit power, and if the receive beam is narrow enough, it is relatively immune to range ambiguities. Compared to direct radiating arrays with digital beam- forming, it is much simpler to implement, uses currently available technologies, is better suited for longer wavelength systems, and does not require extremely high data rates or onboard processing.

Seismic migration for SAR focusing: Interferometrical applications

NASA Astrophysics Data System (ADS)

Prati, C.; Montiguarnieri, A.; Damonti, E.; Rocca, F.

SAR (Synthetic Aperture Radar) data focusing is analyzed from a theoretical point of view. Two applications of a SAR data processing algorithm are presented, where the phases of the returns are used for the recovery of interesting parameters of the observed scenes. Migration techniques, similar to those used in seismic signal processing for oil prospecting, were implemented for the determination of the terrain altitude map from a satellite and the evaluation of the sensor attitude for an airplane. A satisfying precision was achieved, since it was shown how an interferometric system is able to detect variations of the airplane roll angle of a small fraction of a degree.

Phase unwrapping in three dimensions with application to InSAR time series.

PubMed

Hooper, Andrew; Zebker, Howard A

2007-09-01

The problem of phase unwrapping in two dimensions has been studied extensively in the past two decades, but the three-dimensional (3D) problem has so far received relatively little attention. We develop here a theoretical framework for 3D phase unwrapping and also describe two algorithms for implementation, both of which can be applied to synthetic aperture radar interferometry (InSAR) time series. We test the algorithms on simulated data and find both give more accurate results than a two-dimensional algorithm. When applied to actual InSAR time series, we find good agreement both between the algorithms and with ground truth.

43. FLOOR PLAN OF POWER HOUSE, EXHIBIT L, SANTA ANA ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. FLOOR PLAN OF POWER HOUSE, EXHIBIT L, SANTA ANA RIVER NO. 2 PROJECT, APR. 30, 1945. SCE drawing no. 523643 (sheet no. 14; for filing with Federal Power Commission). - Santa Ana River Hydroelectric System, SAR-2 Powerhouse, Redlands, San Bernardino County, CA

Urban-area extraction from polarimetric SAR image using combination of target decomposition and orientation angle

NASA Astrophysics Data System (ADS)

Zou, Bin; Lu, Da; Wu, Zhilu; Qiao, Zhijun G.

2016-05-01

The results of model-based target decomposition are the main features used to discriminate urban and non-urban area in polarimetric synthetic aperture radar (PolSAR) application. Traditional urban-area extraction methods based on modelbased target decomposition usually misclassified ground-trunk structure as urban-area or misclassified rotated urbanarea as forest. This paper introduces another feature named orientation angle to improve urban-area extraction scheme for the accurate mapping in urban by PolSAR image. The proposed method takes randomness of orientation angle into account for restriction of urban area first and, subsequently, implements rotation angle to improve results that oriented urban areas are recognized as double-bounce objects from volume scattering. ESAR L-band PolSAR data of the Oberpfaffenhofen Test Site Area was used to validate the proposed algorithm.

Linear Approximation SAR Azimuth Processing Study

NASA Technical Reports Server (NTRS)

Lindquist, R. B.; Masnaghetti, R. K.; Belland, E.; Hance, H. V.; Weis, W. G.

1979-01-01

A segmented linear approximation of the quadratic phase function that is used to focus the synthetic antenna of a SAR was studied. Ideal focusing, using a quadratic varying phase focusing function during the time radar target histories are gathered, requires a large number of complex multiplications. These can be largely eliminated by using linear approximation techniques. The result is a reduced processor size and chip count relative to ideally focussed processing and a correspondingly increased feasibility for spaceworthy implementation. A preliminary design and sizing for a spaceworthy linear approximation SAR azimuth processor meeting requirements similar to those of the SEASAT-A SAR was developed. The study resulted in a design with approximately 1500 IC's, 1.2 cubic feet of volume, and 350 watts of power for a single look, 4000 range cell azimuth processor with 25 meters resolution.

Operational Use of Civil Space-Based Synthetic Aperture Radar (SAR)

NASA Technical Reports Server (NTRS)

Montgomery, Donald R. (Editor)

1996-01-01

Synthetic Aperture Radar (SAR) is a remote-sensing technology which uses the motion of the aircraft or spacecraft carrying the radar to synthesize an antenna aperture larger than the physical antenna to yield a high-spatial resolution imaging capability. SAR systems can thus obtain high-spatial resolution geophysical measurements of the Earth over wide surface areas, under all-weather, day/night conditions. This report was prepared to document the results of a six-month study by an Ad Hoc Interagency Working Group on the Operational Use of Civil (i.e., non-military) Space-based Synthetic Aperture Radar (SAR). The Assistant Administrator of NOAA for Satellite and Information Services convened this working group and chaired three meetings of the group over a six-month period. This action was taken in response to a request by the Associate Administrator of NASA for Mission to Planet Earth for an assessment of operational applications of SAR to be accomplished in parallel with a separate study requested of the Committee on Earth Studies of the Space Studies Board of the National Research Council on the scientific results of SAR research missions. The representatives of participating agencies are listed following the Preface. There was no formal charter for the working group or long term plans for future meetings. However, the working group may be reconstituted in the future as a coordination body for multiagency use of operational SAR systems.

DInSAR time series generation within a cloud computing environment: from ERS to Sentinel-1 scenario

NASA Astrophysics Data System (ADS)

Casu, Francesco; Elefante, Stefano; Imperatore, Pasquale; Lanari, Riccardo; Manunta, Michele; Zinno, Ivana; Mathot, Emmanuel; Brito, Fabrice; Farres, Jordi; Lengert, Wolfgang

2013-04-01

One of the techniques that will strongly benefit from the advent of the Sentinel-1 system is Differential SAR Interferometry (DInSAR), which has successfully demonstrated to be an effective tool to detect and monitor ground displacements with centimetre accuracy. The geoscience communities (volcanology, seismicity, …), as well as those related to hazard monitoring and risk mitigation, make extensively use of the DInSAR technique and they will take advantage from the huge amount of SAR data acquired by Sentinel-1. Indeed, such an information will successfully permit the generation of Earth's surface displacement maps and time series both over large areas and long time span. However, the issue of managing, processing and analysing the large Sentinel data stream is envisaged by the scientific community to be a major bottleneck, particularly during crisis phases. The emerging need of creating a common ecosystem in which data, results and processing tools are shared, is envisaged to be a successful way to address such a problem and to contribute to the information and knowledge spreading. The Supersites initiative as well as the ESA SuperSites Exploitation Platform (SSEP) and the ESA Cloud Computing Operational Pilot (CIOP) projects provide effective answers to this need and they are pushing towards the development of such an ecosystem. It is clear that all the current and existent tools for querying, processing and analysing SAR data are required to be not only updated for managing the large data stream of Sentinel-1 satellite, but also reorganized for quickly replying to the simultaneous and highly demanding user requests, mainly during emergency situations. This translates into the automatic and unsupervised processing of large amount of data as well as the availability of scalable, widely accessible and high performance computing capabilities. The cloud computing environment permits to achieve all of these objectives, particularly in case of spike and peak requests of processing resources linked to disaster events. This work aims at presenting a parallel computational model for the widely used DInSAR algorithm named as Small BAseline Subset (SBAS), which has been implemented within the cloud computing environment provided by the ESA-CIOP platform. This activity has resulted in developing a scalable, unsupervised, portable, and widely accessible (through a web portal) parallel DInSAR computational tool. The activity has rewritten and developed the SBAS application algorithm within a parallel system environment, i.e., in a form that allows us to benefit from multiple processing units. This requires the devising a parallel version of the SBAS algorithm and its subsequent implementation, implying additional complexity in algorithm designing and an efficient multi processor programming, with the final aim of a parallel performance optimization. Although the presented algorithm has been designed to work with Sentinel-1 data, it can also process other satellite SAR data (ERS, ENVISAT, CSK, TSX, ALOS). Indeed, the performance analysis of the implemented SBAS parallel version has been tested on the full ASAR archive (64 acquisitions) acquired over the Napoli Bay, a volcanic and densely urbanized area in Southern Italy. The full processing - from the raw data download to the generation of DInSAR time series - has been carried out by engaging 4 nodes, each one with 2 cores and 16 GB of RAM, and has taken about 36 hours, with respect to about 135 hours of the sequential version. Extensive analysis on other test areas significant from DInSAR and geophysical viewpoint will be presented. Finally, preliminary performance evaluation of the presented approach within the Sentinel-1 scenario will be provided.

A User-Oriented Methodology for DInSAR Time Series Analysis and Interpretation: Landslides and Subsidence Case Studies

NASA Astrophysics Data System (ADS)

Notti, Davide; Calò, Fabiana; Cigna, Francesca; Manunta, Michele; Herrera, Gerardo; Berti, Matteo; Meisina, Claudia; Tapete, Deodato; Zucca, Francesco

2015-11-01

Recent advances in multi-temporal Differential Synthetic Aperture Radar (SAR) Interferometry (DInSAR) have greatly improved our capability to monitor geological processes. Ground motion studies using DInSAR require both the availability of good quality input data and rigorous approaches to exploit the retrieved Time Series (TS) at their full potential. In this work we present a methodology for DInSAR TS analysis, with particular focus on landslides and subsidence phenomena. The proposed methodology consists of three main steps: (1) pre-processing, i.e., assessment of a SAR Dataset Quality Index (SDQI) (2) post-processing, i.e., application of empirical/stochastic methods to improve the TS quality, and (3) trend analysis, i.e., comparative implementation of methodologies for automatic TS analysis. Tests were carried out on TS datasets retrieved from processing of SAR imagery acquired by different radar sensors (i.e., ERS-1/2 SAR, RADARSAT-1, ENVISAT ASAR, ALOS PALSAR, TerraSAR-X, COSMO-SkyMed) using advanced DInSAR techniques (i.e., SqueeSAR™, PSInSAR™, SPN and SBAS). The obtained values of SDQI are discussed against the technical parameters of each data stack (e.g., radar band, number of SAR scenes, temporal coverage, revisiting time), the retrieved coverage of the DInSAR results, and the constraints related to the characterization of the investigated geological processes. Empirical and stochastic approaches were used to demonstrate how the quality of the TS can be improved after the SAR processing, and examples are discussed to mitigate phase unwrapping errors, and remove regional trends, noise and anomalies. Performance assessment of recently developed methods of trend analysis (i.e., PS-Time, Deviation Index and velocity TS) was conducted on two selected study areas in Northern Italy affected by land subsidence and landslides. Results show that the automatic detection of motion trends enhances the interpretation of DInSAR data, since it provides an objective picture of the deformation behaviour recorded through TS and therefore contributes to the understanding of the on-going geological processes.

Contrast Enhancement in TOF cerebral angiography at 7 T using Saturation and MT pulses under SAR constraints: impact of VERSE and sparse pulses

PubMed Central

Schmitter, Sebastian; Bock, Michael; Johst, Sören; Auerbach, Edward J.; Uğurbil, Kâmil; Van de Moortele, Pierre-François

2011-01-01

Cerebral 3D time of flight (TOF) angiography significantly benefits from ultra high fields, mainly due to higher SNR and to longer T1 relaxation time of static brain tissues, however, SAR significantly increases with B0. Thus, additional RF pulses commonly used at lower field strengths to improve TOF contrast such as saturation of venous signal and improved background suppression by magnetization transfer typically cannot be used at higher fields. In this work we aimed at reducing SAR for each RF pulse category in a TOF sequence. We use the VERSE principle for the slab selective TOF excitation as well as the venous saturation RF pulses. Additionally, MT pulses are implemented by sparsely applying the pulses only during acquisition of the central k-space lines to limit their SAR contribution. Image quality, angiographic contrast and SAR reduction were investigated as a function of VERSE parameters and of the total number of MT pulses applied. Based on these results, a TOF protocol was generated that increases the angiographic contrast by more than 50% and reduces subcutaneous fat signal while keeping the resulting SAR within regulatory limits. PMID:22139829

SAR and scan-time optimized 3D whole-brain double inversion recovery imaging at 7T.

PubMed

Pracht, Eberhard D; Feiweier, Thorsten; Ehses, Philipp; Brenner, Daniel; Roebroeck, Alard; Weber, Bernd; Stöcker, Tony

2018-05-01

The aim of this project was to implement an ultra-high field (UHF) optimized double inversion recovery (DIR) sequence for gray matter (GM) imaging, enabling whole brain coverage in short acquisition times ( ≈5 min, image resolution 1 mm 3 ). A 3D variable flip angle DIR turbo spin echo (TSE) sequence was optimized for UHF application. We implemented an improved, fast, and specific absorption rate (SAR) efficient TSE imaging module, utilizing improved reordering. The DIR preparation was tailored to UHF application. Additionally, fat artifacts were minimized by employing water excitation instead of fat saturation. GM images, covering the whole brain, were acquired in 7 min scan time at 1 mm isotropic resolution. SAR issues were overcome by using a dedicated flip angle calculation considering SAR and SNR efficiency. Furthermore, UHF related artifacts were minimized. The suggested sequence is suitable to generate GM images with whole-brain coverage at UHF. Due to the short total acquisition times and overall robustness, this approach can potentially enable DIR application in a routine setting and enhance lesion detection in neurological diseases. Magn Reson Med 79:2620-2628, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Development and validation of a MRgHIFU non-invasive tissue acoustic property estimation technique.

PubMed

Johnson, Sara L; Dillon, Christopher; Odéen, Henrik; Parker, Dennis; Christensen, Douglas; Payne, Allison

2016-11-01

MR-guided high-intensity focussed ultrasound (MRgHIFU) non-invasive ablative surgeries have advanced into clinical trials for treating many pathologies and cancers. A remaining challenge of these surgeries is accurately planning and monitoring tissue heating in the face of patient-specific and dynamic acoustic properties of tissues. Currently, non-invasive measurements of acoustic properties have not been implemented in MRgHIFU treatment planning and monitoring procedures. This methods-driven study presents a technique using MR temperature imaging (MRTI) during low-temperature HIFU sonications to non-invasively estimate sample-specific acoustic absorption and speed of sound values in tissue-mimicking phantoms. Using measured thermal properties, specific absorption rate (SAR) patterns are calculated from the MRTI data and compared to simulated SAR patterns iteratively generated via the Hybrid Angular Spectrum (HAS) method. Once the error between the simulated and measured patterns is minimised, the estimated acoustic property values are compared to the true phantom values obtained via an independent technique. The estimated values are then used to simulate temperature profiles in the phantoms, and compared to experimental temperature profiles. This study demonstrates that trends in acoustic absorption and speed of sound can be non-invasively estimated with average errors of 21% and 1%, respectively. Additionally, temperature predictions using the estimated properties on average match within 1.2 °C of the experimental peak temperature rises in the phantoms. The positive results achieved in tissue-mimicking phantoms presented in this study indicate that this technique may be extended to in vivo applications, improving HIFU sonication temperature rise predictions and treatment assessment.

The severe acute respiratory syndrome: impact on travel and tourism.

PubMed

Wilder-Smith, Annelies

2006-03-01

SARS and travel are intricately interlinked. Travelers belonged to those primarily affected in the early stages of the outbreak, travelers became vectors of the disease, and finally, travel and tourism themselves became the victims. The outbreak of SARS created international anxiety because of its novelty, its ease of transmission in certain settings, and the speed of its spread through jet travel, combined with extensive media coverage. The psychological impacts of SARS, coupled with travel restrictions imposed by various national and international authorities, have diminished international travel in 2003, far beyond the limitations to truly SARS hit areas. Governments and press, especially in non SARS affected areas, have been slow to strike the right balance between timely and frequent risk communication and placing risk in the proper context. Screening at airport entry points is costly, has a low yield and is not sufficient in itself. The low yield in detecting SARS is most likely due to a combination of factors, such as travel advisories which resulted in reduced travel to and from SARS affected areas, implementation of effective pre-departure screening at airports in SARS-hit countries, and a rapid decline in new cases at the time when screening was finally introduced. Rather than investing in airport screening measures to detect rare infectious diseases, investments should be used to strengthen screening and infection control capacities at points of entry into the healthcare system. If SARS reoccurs, the subsequent outbreak will be smaller and more easily contained if the lessons learnt from the recent epidemic are applied. Lessons learnt during the outbreak in relation to international travel will be discussed.

Automatic Coregistration for Multiview SAR Images in Urban Areas

NASA Astrophysics Data System (ADS)

Xiang, Y.; Kang, W.; Wang, F.; You, H.

2017-09-01

Due to the high resolution property and the side-looking mechanism of SAR sensors, complex buildings structures make the registration of SAR images in urban areas becomes very hard. In order to solve the problem, an automatic and robust coregistration approach for multiview high resolution SAR images is proposed in the paper, which consists of three main modules. First, both the reference image and the sensed image are segmented into two parts, urban areas and nonurban areas. Urban areas caused by double or multiple scattering in a SAR image have a tendency to show higher local mean and local variance values compared with general homogeneous regions due to the complex structural information. Based on this criterion, building areas are extracted. After obtaining the target regions, L-shape structures are detected using the SAR phase congruency model and Hough transform. The double bounce scatterings formed by wall and ground are shown as strong L- or T-shapes, which are usually taken as the most reliable indicator for building detection. According to the assumption that buildings are rectangular and flat models, planimetric buildings are delineated using the L-shapes, then the reconstructed target areas are obtained. For the orignal areas and the reconstructed target areas, the SAR-SIFT matching algorithm is implemented. Finally, correct corresponding points are extracted by the fast sample consensus (FSC) and the transformation model is also derived. The experimental results on a pair of multiview TerraSAR images with 1-m resolution show that the proposed approach gives a robust and precise registration performance, compared with the orignal SAR-SIFT method.

Characterizing and estimating noise in InSAR and InSAR time series with MODIS

USGS Publications Warehouse

Barnhart, William D.; Lohman, Rowena B.

2013-01-01

InSAR time series analysis is increasingly used to image subcentimeter displacement rates of the ground surface. The precision of InSAR observations is often affected by several noise sources, including spatially correlated noise from the turbulent atmosphere. Under ideal scenarios, InSAR time series techniques can substantially mitigate these effects; however, in practice the temporal distribution of InSAR acquisitions over much of the world exhibit seasonal biases, long temporal gaps, and insufficient acquisitions to confidently obtain the precisions desired for tectonic research. Here, we introduce a technique for constraining the magnitude of errors expected from atmospheric phase delays on the ground displacement rates inferred from an InSAR time series using independent observations of precipitable water vapor from MODIS. We implement a Monte Carlo error estimation technique based on multiple (100+) MODIS-based time series that sample date ranges close to the acquisitions times of the available SAR imagery. This stochastic approach allows evaluation of the significance of signals present in the final time series product, in particular their correlation with topography and seasonality. We find that topographically correlated noise in individual interferograms is not spatially stationary, even over short-spatial scales (<10 km). Overall, MODIS-inferred displacements and velocities exhibit errors of similar magnitude to the variability within an InSAR time series. We examine the MODIS-based confidence bounds in regions with a range of inferred displacement rates, and find we are capable of resolving velocities as low as 1.5 mm/yr with uncertainties increasing to ∼6 mm/yr in regions with higher topographic relief.

28. PLANS AND SECTIONS OF POWERHOUSE. SANTA ANA NO. 3, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

28. PLANS AND SECTIONS OF POWERHOUSE. SANTA ANA NO. 3, EXHIBIT L, JAN. 25, 1956 (SHEET 8; FOR FILING WITH FEDERAL POWER COMMISSION). SCE drawing no. 541729. - Santa Ana River Hydroelectric System, SAR-3 Powerhouse, San Bernardino National Forest, Redlands, San Bernardino County, CA

4. PLAN AND PROFILES OF PENSTOCK AND SPILLWAY PIPE, SANTA ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. PLAN AND PROFILES OF PENSTOCK AND SPILLWAY PIPE, SANTA ANA NO. 3, EXHIBIT L, JAN. 25, 1956. SCE drawing no. 541726 (sheet 7; for filing with Federal Power Commission). - Santa Ana River Hydroelectric System, SAR-3 Forebay & Penstock, Redlands, San Bernardino County, CA

Monitoring of surface deformation in open pit mine using DInSAR time-series: a case study in the N5W iron mine (Carajás, Brazil) using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Mura, José C.; Paradella, Waldir R.; Gama, Fabio F.; Santos, Athos R.; Galo, Mauricio; Camargo, Paulo O.; Silva, Arnaldo Q.; Silva, Guilherme G.

2014-10-01

We present an investigation of surface deformation using Differential SAR Interferometry (DInSAR) time-series carried out in an active open pit iron mine, the N5W, located in the Carajás Mineral Province (Brazilian Amazon region), using 33 TerraSAR-X (TSX-1) scenes. This mine has presented a historical of instability and surface monitoring measurements over sectors of the mine (pit walls) have been done based on ground based radar. Two complementary approaches were used: the standard DInSAR configuration, as an early warning of the slope instability conditions, and the DInSAR timeseries analysis. In order to decrease the topographic phase error a high resolution DEM was generated based on a stereo GeoEye-1 pair. Despite the fact that a DinSAR contains atmospheric and topographic phase artifacts and noise, it was possible to detect deformation in some interferometric pairs, covering pit benches, road ramps and waste piles. The timeseries analysis was performed using the 31 interferometric pairs, which were selected based on the highest mean coherence of a stack of 107 interferograms, presenting less phase unwrapping errors. The time-series deformation was retrieved by the Least-Squares (LS) solution using an extension of the Singular Value Decomposition (SVD), with a set of additional weighted constrain on the acceleration deformation. The atmospheric phase artifacts were filtered in the space-time domain and the DEM height errors were estimated based on the normal baseline diversity. The DInSAR time-series investigation showed good results for monitoring surface displacement in the N5W mine located in a tropical rainforest environment, providing very useful information about the ground movement for alarm, planning and risk assessment.

Foldbelt exploration with synthetic aperture radar (SAR) in Papua New Guinea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ellis, J.M.; Pruett, F.D.

1987-05-01

Synthetic aperture radar (SAR) is being successfully used within the southern fold and thrust belt of Papua New Guinea to map surface structure and stratigraphy and to help plan a hydrocarbon exploration program. The airborne SAR imagery, along with other surface data, is used as a primary exploration tool because acquisition of acceptable seismic data is extremely costly due to extensive outcrops of Tertiary Darai Limestone which develops rugged karst topography. Most anticlines in the licenses are capped with this deeply karstified limestone. The region is ideally suited to geologic analysis using remote sensing technology. The area is seldom cloudmore » free and is covered with tropical rain forest, and geologic field studies are limited. The widespread karst terrain is exceedingly dangerous, if not impossible, to traverse on the ground. SAR is used to guide ongoing field work, modeling of subsurface structure, and selection of well locations. SAR provides their explorationists with an excellent data base because (1) structure is enhanced with low illumination, (2) resolution is 6 x 12 m, (3) digital reprocessing is possible, (4) clouds are penetrated by the SAR, and (5) the survey was designed for stereoscopic photogeology. Landsat images and vertical aerial photographs complement SAR but provide subdued structural information because of minimal shadowing (due to high sun angles) and the jungle cover. SAR imagery reveals large-scale mass wasting that has led to a reevaluation of previously acquired field data. Lithologies can be recognized by textural and tonal changes on the SAR images despite near-continuous canopy of jungle. Reprocessing and contrast stretching of the digital radar imagery provide additional geologic information.« less

A new approach for river flood extent delineation in rural and urban areas combining RADARSAT-2 imagery and flood recurrence interval data

NASA Astrophysics Data System (ADS)

Tanguy, Marion; Bernier, Monique; Chokmani, Karem

2015-04-01

When a flood hits an inhabited area, managers and services responsible for public safety need precise, reliable and up to date maps of the areas affected by the flood, in order to quickly roll out and to coordinate the adequate intervention and assistance plans required to limit the human and material damages caused by the disaster. Synthetic aperture radar (SAR) sensors are now considered as one of the most adapted tool for flood detection and mapping in a context of crisis management. Indeed, due to their capacity to acquire data night and day, in almost all meteorological conditions, SAR sensors allow the acquisition of synoptic but detailed views of the areas affected by the flood, even during the active phases of the event. Moreover, new generation sensors such as RADARSAT-2, TerraSAR-X, COSMO-SkyMed, are providing very high resolution images of the disaster (down to 1m ground resolution). Further, critical improvements have been made on the temporal repetitivity of acquisitions and on data availability, through the development of satellite constellations (i.e the four COSMO-Skymed or the Sentinel-1A and 1B satellites) and thanks to the implementation of the International Charter "Space and Major Disasters", which guarantees high priority images acquisition and delivery with 4 to 12 hours. If detection of open water flooded areas is relatively straightforward with SAR imagery, flood detection in built-up areas is often associated with important issues. Indeed, because of the side looking geometry of the SAR sensors, structures such as tall vegetation and structures parallel to the satellite direction of travel may produce shadow and layover effects, leading to important over and under-detections of flooded pixels. Besides, the numerous permanent water-surfaces like radar response areas present in built-up environments, such as parking lots, roads etc., may be mixed up with flooded areas, resulting in substantial inaccuracies in the final flood map. In spite of the many efforts recently done toward the improvements of the accuracy of the processing algorithms for flood detection in urban areas with high resolution SAR imagery, these algorithms still encounter difficulties to detect urban flooded pixels with precision. The difficulties do not seem to be only ascribable to the choice of SAR image processing methods, but can also be imputed to the limitations of the SAR imaging technique itself in urban areas. We propose a fully automatic and effective approach for near-real time delineation of urban and rural flooded areas, which combines the capacity of SAR imagery to detect open water areas, and explicit hydrodynamic characteristics of the region affected by the flood, expressed through flood recurrence interval data. This innovative approach has been tested with RADARSAT-2 Fine and Ultrafine Mode images acquired during the 2011 Richelieu River flooding, in Canada. It proved successful in accurately delineating flooding in urban and rural areas, with a RMSE inferior to 2 pixels.

Wab-InSAR: a new wavelet based InSAR time series technique applied to volcanic and tectonic areas

NASA Astrophysics Data System (ADS)

Walter, T. R.; Shirzaei, M.; Nankali, H.; Roustaei, M.

2009-12-01

Modern geodetic techniques such as InSAR and GPS provide valuable observations of the deformation field. Because of the variety of environmental interferences (e.g., atmosphere, topography distortion) and incompleteness of the models (assumption of the linear model for deformation), those observations are usually tainted by various systematic and random errors. Therefore we develop and test new methods to identify and filter unwanted periodic or episodic artifacts to obtain accurate and precise deformation measurements. Here we present and implement a new wavelet based InSAR (Wab-InSAR) time series approach. Because wavelets are excellent tools for identifying hidden patterns and capturing transient signals, we utilize wavelet functions for reducing the effect of atmospheric delay and digital elevation model inaccuracies. Wab-InSAR is a model free technique, reducing digital elevation model errors in individual interferograms using a 2D spatial Legendre polynomial wavelet filter. Atmospheric delays are reduced using a 3D spatio-temporal wavelet transform algorithm and a novel technique for pixel selection. We apply Wab-InSAR to several targets, including volcano deformation processes at Hawaii Island, and mountain building processes in Iran. Both targets are chosen to investigate large and small amplitude signals, variable and complex topography and atmospheric effects. In this presentation we explain different steps of the technique, validate the results by comparison to other high resolution processing methods (GPS, PS-InSAR, SBAS) and discuss the geophysical results.

Measurement of Seaward Ground Displacements on Coastal Landfill Area Using Radar Interferometry

NASA Astrophysics Data System (ADS)

Baek, W.-K.; Jung, H.-S.

2018-04-01

In order to understand the mechanism of subsidence and help reducing damage, researchers has been observed the line-of-sight subsidence on the Noksan industrial complex using SAR Interferometry(InSAR) and suggested subsidence prediction models. Although these researches explained a spatially uneven ground subsidence near the seaside, they could not have been explained the occurrence of the newly proposed seaward horizontal, especially nearly north-ward, displacement because of the geometric limitation of InSAR measurements. In this study, we measured the seaward ground displacements trend on the coastal landfill area, Noksan Industrial Complex. We set the interferometric pairs from an ascending and a descending orbits strip map data of ALOS PALSAR2. We employed InSAR and MAI stacking approaches for the both orbits respectively in order to improve the measurement. Finally, seaward deformation was estimated by retrieving three-dimensional displacements from multi-geometric displacements. As a results, maximally 3.3 and 0.7 cm/year of ground displacements for the vertical and seaward directions. In further study, we plan to generate InSAR and MAI stacking measurements with additional SAR data to mitigate tropospheric effect and noise well. Such a seaward observation approach using spaceborne radar is expected to be effective in observing the long-term movements on coastal landfill area.

How did general practitioners protect themselves, their family, and staff during the SARS epidemic in Hong Kong?

PubMed Central

Wong, W; Lee, A; Tsang, K; Wong, S

2004-01-01

Context: Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease and how the frontline community doctors respond to it is not known. Objectives: To explore the impact of SARS on general practitioners (GPs) in Hong Kong. Design: A cross sectional survey. Setting: Community based primary care clinics. Participants: 183 family medicine tutors affiliated with a local university. Postal survey sent to all tutors with a 74.8% response rate. Main outcome measures: Change of clinical behaviour and practices during the epidemic; anxiety level of primary care doctors. Results: All agreed SARS had changed their clinical practices. Significant anxiety was found in family doctors. Three quarters of respondents recalled requesting more investigations while a quarter believed they had over-prescribed antibiotics. GPs who were exposed to SARS or who had worked in high infection districts were less likely to quarantine themselves (10.8% versus 33.3%; p<0.01; 6.5% versus 27.5%; p<0.01 respectively). Exposure to SARS, the infection rates in their working district, and anxiety levels had significant impact on the level of protection or prescribing behaviour. Conclusion: The clinical practice of GPs changed significantly as a result of SARS. Yet, those did not quarantine themselves suggesting other factors may have some part to play. As failure to apply isolation precautions to suspected cases of SARS was one major reason for its spread, a contingency plan from the government to support family doctors is of utmost importance. Interface between private and public sectors are needed in Hong Kong to prepare for any future epidemics. PMID:14966227

How did general practitioners protect themselves, their family, and staff during the SARS epidemic in Hong Kong?

PubMed

Wong, W C W; Lee, A; Tsang, K K; Wong, S Y S

2004-03-01

Severe acute respiratory syndrome (SARS) is a newly emerging infectious disease and how the frontline community doctors respond to it is not known. To explore the impact of SARS on general practitioners (GPs) in Hong Kong. A cross sectional survey. Community based primary care clinics. 183 family medicine tutors affiliated with a local university. Postal survey sent to all tutors with a 74.8% response rate. Change of clinical behaviour and practices during the epidemic; anxiety level of primary care doctors. All agreed SARS had changed their clinical practices. Significant anxiety was found in family doctors. Three quarters of respondents recalled requesting more investigations while a quarter believed they had over-prescribed antibiotics. GPs who were exposed to SARS or who had worked in high infection districts were less likely to quarantine themselves (10.8% versus 33.3%; p<0.01; 6.5% versus 27.5%; p<0.01 respectively). Exposure to SARS, the infection rates in their working district, and anxiety levels had significant impact on the level of protection or prescribing behaviour. The clinical practice of GPs changed significantly as a result of SARS. Yet, those did not quarantine themselves suggesting other factors may have some part to play. As failure to apply isolation precautions to suspected cases of SARS was one major reason for its spread, a contingency plan from the government to support family doctors is of utmost importance. Interface between private and public sectors are needed in Hong Kong to prepare for any future epidemics.

L-band InSAR Penetration Depth Experiment, North Slope Alaska

NASA Astrophysics Data System (ADS)

Muskett, Reginald

2017-04-01

Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA's SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solid-earth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the P- to X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic Alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising form permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales.

26. BUILDING PLANS FOR MENTONE POWER HOUSE, PACIFIC LIGHT AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. BUILDING PLANS FOR MENTONE POWER HOUSE, PACIFIC LIGHT AND POWER CO., OCT. 7, 1903. R.S. MASSON, CONSULTING ELECTRICAL ENGINEER, SAN FRANCISCO AND LOS ANGELES. SCE drawing no. 52306. - Santa Ana River Hydroelectric System, SAR-3 Powerhouse, San Bernardino National Forest, Redlands, San Bernardino County, CA

Adaptive thresholding algorithm based on SAR images and wind data to segment oil spills along the northwest coast of the Iberian Peninsula.

PubMed

Mera, David; Cotos, José M; Varela-Pet, José; Garcia-Pineda, Oscar

2012-10-01

Satellite Synthetic Aperture Radar (SAR) has been established as a useful tool for detecting hydrocarbon spillage on the ocean's surface. Several surveillance applications have been developed based on this technology. Environmental variables such as wind speed should be taken into account for better SAR image segmentation. This paper presents an adaptive thresholding algorithm for detecting oil spills based on SAR data and a wind field estimation as well as its implementation as a part of a functional prototype. The algorithm was adapted to an important shipping route off the Galician coast (northwest Iberian Peninsula) and was developed on the basis of confirmed oil spills. Image testing revealed 99.93% pixel labelling accuracy. By taking advantage of multi-core processor architecture, the prototype was optimized to get a nearly 30% improvement in processing time. Copyright © 2012 Elsevier Ltd. All rights reserved.

Phase correction and error estimation in InSAR time series analysis

NASA Astrophysics Data System (ADS)

Zhang, Y.; Fattahi, H.; Amelung, F.

2017-12-01

During the last decade several InSAR time series approaches have been developed in response to the non-idea acquisition strategy of SAR satellites, such as large spatial and temporal baseline with non-regular acquisitions. The small baseline tubes and regular acquisitions of new SAR satellites such as Sentinel-1 allows us to form fully connected networks of interferograms and simplifies the time series analysis into a weighted least square inversion of an over-determined system. Such robust inversion allows us to focus more on the understanding of different components in InSAR time-series and its uncertainties. We present an open-source python-based package for InSAR time series analysis, called PySAR (https://yunjunz.github.io/PySAR/), with unique functionalities for obtaining unbiased ground displacement time-series, geometrical and atmospheric correction of InSAR data and quantifying the InSAR uncertainty. Our implemented strategy contains several features including: 1) improved spatial coverage using coherence-based network of interferograms, 2) unwrapping error correction using phase closure or bridging, 3) tropospheric delay correction using weather models and empirical approaches, 4) DEM error correction, 5) optimal selection of reference date and automatic outlier detection, 6) InSAR uncertainty due to the residual tropospheric delay, decorrelation and residual DEM error, and 7) variance-covariance matrix of final products for geodetic inversion. We demonstrate the performance using SAR datasets acquired by Cosmo-Skymed and TerraSAR-X, Sentinel-1 and ALOS/ALOS-2, with application on the highly non-linear volcanic deformation in Japan and Ecuador (figure 1). Our result shows precursory deformation before the 2015 eruptions of Cotopaxi volcano, with a maximum uplift of 3.4 cm on the western flank (fig. 1b), with a standard deviation of 0.9 cm (fig. 1a), supporting the finding by Morales-Rivera et al. (2017, GRL); and a post-eruptive subsidence on the same area, with a maximum of -3 +/- 0.9 cm (fig. 1c). Time-series displacement map (fig. 2) shows a highly non-linear deformation behavior, indicating the complicated magma propagation process during this eruption cycle.

Making SAR Data Accessible - ASF's ALOS PALSAR Radiometric Terrain Correction Project

NASA Astrophysics Data System (ADS)

Meyer, F. J.; Arko, S. A.; Gens, R.

2015-12-01

While SAR data have proven valuable for a wide range of geophysical research questions, so far, largely only the SAR-educated science communities have been able to fully exploit the information content of internationally available SAR archives. The main issues that have been preventing a more widespread utilization of SAR are related to (1) the diversity and complexity of SAR data formats, (2) the complexity of the processing flows needed to extract geophysical information from SAR, (3) the lack of standardization and automation of these processing flows, and (4) the often ignored geocoding procedures, leaving the data in image coordinate space. In order to improve upon this situation, ASF's radiometric terrain-correction (RTC) project is generating uniformly formatted and easily accessible value-added products from the ASF Distributed Active Archive Center's (DAAC) five-year archive of JAXA's ALOS PALSAR sensor. Specifically, the project applies geometric and radiometric corrections to SAR data to allow for an easy and direct combination of obliquely acquired SAR data with remote sensing imagery acquired in nadir observation geometries. Finally, the value-added data is provided to the user in the broadly accepted Geotiff format, in order to support the easy integration of SAR data into GIS environments. The goal of ASF's RTC project is to make SAR data more accessible and more attractive to the broader SAR applications community, especially to those users that currently have limited SAR expertise. Production of RTC products commenced October 2014 and will conclude late in 2015. As of July 2015, processing of 71% of ASF's ALOS PALSAR archive was completed. Adding to the utility of this dataset are recent changes to the data access policy that allow the full-resolution RTC products to be provided to the public, without restriction. In this paper we will introduce the processing flow that was developed for the RTC project and summarize the calibration and validation procedures that were implemented to determine and monitor system performance. The paper will also show the current progress of RTC processing, provide examples of generated data sets, and demonstrate the benefit of the RTC archives for applications such as land-use classification and change detection.

Spatially variant apodization for squinted synthetic aperture radar images.

PubMed

Castillo-Rubio, Carlos F; Llorente-Romano, Sergio; Burgos-García, Mateo

2007-08-01

Spatially variant apodization (SVA) is a nonlinear sidelobe reduction technique that improves sidelobe level and preserves resolution at the same time. This method implements a bidimensional finite impulse response filter with adaptive taps depending on image information. Some papers that have been previously published analyze SVA at the Nyquist rate or at higher rates focused on strip synthetic aperture radar (SAR). This paper shows that traditional SVA techniques are useless when the sensor operates with a squint angle. The reasons for this behaviour are analyzed, and a new implementation that largely improves the results is presented. The algorithm is applied to simulated SAR images in order to demonstrate the good quality achieved along with efficient computation.

Comparison and Analysis of Geometric Correction Models of Spaceborne SAR

PubMed Central

Jiang, Weihao; Yu, Anxi; Dong, Zhen; Wang, Qingsong

2016-01-01

Following the development of synthetic aperture radar (SAR), SAR images have become increasingly common. Many researchers have conducted large studies on geolocation models, but little work has been conducted on the available models for the geometric correction of SAR images of different terrain. To address the terrain issue, four different models were compared and are described in this paper: a rigorous range-doppler (RD) model, a rational polynomial coefficients (RPC) model, a revised polynomial (PM) model and an elevation derivation (EDM) model. The results of comparisons of the geolocation capabilities of the models show that a proper model for a SAR image of a specific terrain can be determined. A solution table was obtained to recommend a suitable model for users. Three TerraSAR-X images, two ALOS-PALSAR images and one Envisat-ASAR image were used for the experiment, including flat terrain and mountain terrain SAR images as well as two large area images. Geolocation accuracies of the models for different terrain SAR images were computed and analyzed. The comparisons of the models show that the RD model was accurate but was the least efficient; therefore, it is not the ideal model for real-time implementations. The RPC model is sufficiently accurate and efficient for the geometric correction of SAR images of flat terrain, whose precision is below 0.001 pixels. The EDM model is suitable for the geolocation of SAR images of mountainous terrain, and its precision can reach 0.007 pixels. Although the PM model does not produce results as precise as the other models, its efficiency is excellent and its potential should not be underestimated. With respect to the geometric correction of SAR images over large areas, the EDM model has higher accuracy under one pixel, whereas the RPC model consumes one third of the time of the EDM model. PMID:27347973

Simulated annealing with restart strategy for the blood pickup routing problem

NASA Astrophysics Data System (ADS)

Yu, V. F.; Iswari, T.; Normasari, N. M. E.; Asih, A. M. S.; Ting, H.

2018-04-01

This study develops a simulated annealing heuristic with restart strategy (SA_RS) for solving the blood pickup routing problem (BPRP). BPRP minimizes the total length of the routes for blood bag collection between a blood bank and a set of donation sites, each associated with a time window constraint that must be observed. The proposed SA_RS is implemented in C++ and tested on benchmark instances of the vehicle routing problem with time windows to verify its performance. The algorithm is then tested on some newly generated BPRP instances and the results are compared with those obtained by CPLEX. Experimental results show that the proposed SA_RS heuristic effectively solves BPRP.

Custom large scale integrated circuits for spaceborne SAR processors

NASA Technical Reports Server (NTRS)

Tyree, V. C.

1978-01-01

The application of modern LSI technology to the development of a time-domain azimuth correlator for SAR processing is discussed. General design requirements for azimuth correlators for missions such as SEASAT-A, Venus orbital imaging radar (VOIR), and shuttle imaging radar (SIR) are summarized. Several azimuth correlator architectures that are suitable for implementation using custom LSI devices are described. Technical factors pertaining to selection of appropriate LSI technologies are discussed, and the maturity of alternative technologies for spacecraft applications are reported in the context of expected space mission launch dates. The preliminary design of a custom LSI time-domain azimuth correlator device (ACD) being developed for use in future SAR processors is detailed.

DBSAR's First Multimode Flight Campaign

NASA Technical Reports Server (NTRS)

Rincon, Rafael F.; Vega, Manuel; Buenfil, Manuel; Geist, Alessandro; Hilliard, Lawrence; Racette, Paul

2010-01-01

The Digital Beamforming SAR (DBSAR) is an airborne imaging radar system that combines phased array technology, reconfigurable on-board processing and waveform generation, and advances in signal processing to enable techniques not possible with conventional SARs. The system exploits the versatility inherently in phased-array technology with a state-of-the-art data acquisition and real-time processor in order to implement multi-mode measurement techniques in a single radar system. Operational modes include scatterometry over multiple antenna beams, Synthetic Aperture Radar (SAR) over several antenna beams, or Altimetry. The radar was flight tested in October 2008 on board of the NASA P3 aircraft over the Delmarva Peninsula, MD. The results from the DBSAR system performance is presented.

A fast, programmable hardware architecture for the processing of spaceborne SAR data

NASA Technical Reports Server (NTRS)

Bennett, J. R.; Cumming, I. G.; Lim, J.; Wedding, R. M.

1984-01-01

The development of high-throughput SAR processors (HTSPs) for the spaceborne SARs being planned by NASA, ESA, DFVLR, NASDA, and the Canadian Radarsat Project is discussed. The basic parameters and data-processing requirements of the SARs are listed in tables, and the principal problems are identified as real-operations rates in excess of 2 x 10 to the 9th/sec, I/O rates in excess of 8 x 10 to the 6th samples/sec, and control computation loads (as for range cell migration correction) as high as 1.4 x 10 to the 6th instructions/sec. A number of possible HTSP architectures are reviewed; host/array-processor (H/AP) and distributed-control/data-path (DCDP) architectures are examined in detail and illustrated with block diagrams; and a cost/speed comparison of these two architectures is presented. The H/AP approach is found to be adequate and economical for speeds below 1/200 of real time, while DCDP is more cost-effective above 1/50 of real time.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Begoli, Edmon; Boehmann, Brant; DeNap, Frank A

In 2003 a joint effort between the U.S. Department of Homeland Security (DHS) and the U.S. Department of Justice created state and metropolitan intelligence fusion centers. These fusion centers were an effort to share law enforcement, disaster, and terrorism related information and intelligence between state and local jurisdictions and to share terrorism related intelligence between state and local law enforcement agencies and various federal entities. In 2006, DHS commissioned the Oak Ridge National Laboratory to establish and manage a groundbreaking program to assist local, state, and tribal leaders in developing the tools and methods required to anticipate and forestall terroristmore » events and to enhance disaster response. This program, called the Southeast Region Research Initiative (SERRI), combines science and technology with validated operational approaches to address regionally unique requirements and suggest regional solutions with the potential for national application. In 2009, SERRI sponsored the Multistate Sharing Initiative (MSSI) to assist state and metropolitan intelligence fusion centers with sharing information related to a wider variety of state interests than just terrorism. While these fusion centers have been effective at sharing data across organizations within their respective jurisdictions, their organizational structure makes bilateral communication with federal entities convenient and also allows information to be further disbursed to other local entities when appropriate. The MSSI-developed Suspicious Activity Report (SAR) sharing system allows state-to-state sharing of non-terrorism-related law enforcement and disaster information. Currently, the MSSI SAR system is deployed in Alabama, Kentucky, Tennessee, and South Carolina. About 1 year after implementation, cognizant fusion center personnel from each state were contacted to ascertain the status of their MSSI SAR systems. The overwhelming response from these individuals was that the MSSI SAR system was an outstanding success and contributed greatly to the security and resiliency of their states. At least one state commented that SERRI's implementation of the MSSI SAR actually 'jump started' and accelerated deployment and acceptance of the Nationwide Suspicious Activity Reporting Initiative (NSI). While all states were enthusiastic about their systems, South Carolina and Tennessee appeared to be the heaviest users of their respective systems. With NSI taking the load of sharing SARs with other states, Tennessee has redeployed the MSSI SAR system within Tennessee to allow SAR sharing between state and local organizations including Tennessee's three Homeland Security Regions, eleven Homeland Security Districts, and more than 500 police and sheriff offices, as well as with other states. In one success story from South Carolina, the Economy SAR System was used to compile similar SARs from throughout the state which were then forwarded to field liaison officers, emergency management personnel, and law enforcement officers for action.« less

Improving the extraction of crisis information in the context of flood, fire, and landslide rapid mapping using SAR and optical remote sensing data

NASA Astrophysics Data System (ADS)

Martinis, Sandro; Clandillon, Stephen; Twele, André; Huber, Claire; Plank, Simon; Maxant, Jérôme; Cao, Wenxi; Caspard, Mathilde; May, Stéphane

2016-04-01

Optical and radar satellite remote sensing have proven to provide essential crisis information in case of natural disasters, humanitarian relief activities and civil security issues in a growing number of cases through mechanisms such as the Copernicus Emergency Management Service (EMS) of the European Commission or the International Charter 'Space and Major Disasters'. The aforementioned programs and initiatives make use of satellite-based rapid mapping services aimed at delivering reliable and accurate crisis information after natural hazards. Although these services are increasingly operational, they need to be continuously updated and improved through research and development (R&D) activities. The principal objective of ASAPTERRA (Advancing SAR and Optical Methods for Rapid Mapping), the ESA-funded R&D project being described here, is to improve, automate and, hence, speed-up geo-information extraction procedures in the context of natural hazards response. This is performed through the development, implementation, testing and validation of novel image processing methods using optical and Synthetic Aperture Radar (SAR) data. The methods are mainly developed based on data of the German radar satellites TerraSAR-X and TanDEM-X, the French satellite missions Pléiades-1A/1B as well as the ESA missions Sentinel-1/2 with the aim to better characterize the potential and limitations of these sensors and their synergy. The resulting algorithms and techniques are evaluated in real case applications during rapid mapping activities. The project is focussed on three types of natural hazards: floods, landslides and fires. Within this presentation an overview of the main methodological developments in each topic is given and demonstrated in selected test areas. The following developments are presented in the context of flood mapping: a fully automated Sentinel-1 based processing chain for detecting open flood surfaces, a method for the improved detection of flooded vegetation in Sentinel-1data using Entropy/Alpha decomposition, unsupervised Wishart Classification, and object-based post-classification as well as semi-automatic approaches for extracting inundated areas and flood traces in rural and urban areas from VHR and HR optical imagery using machine learning techniques. Methodological developments related to fires are the implementation of fast and robust methods for mapping burnt scars using change detection procedures using SAR (Sentinel-1, TerraSAR-X) and HR optical (e.g. SPOT, Sentinel-2) data as well as the extraction of 3D surface and volume change information from Pléiades stereo-pairs. In the context of landslides, fast and transferable change detection procedures based on SAR (TerraSAR-X) and optical (SPOT) data as well methods for extracting the extent of landslides only based on polarimetric VHR SAR (TerraSAR-X) data are presented.

Reduction and coding of synthetic aperture radar data with Fourier transforms

NASA Technical Reports Server (NTRS)

Tilley, David G.

1995-01-01

Recently, aboard the Space Radar Laboratory (SRL), the two roles of Fourier Transforms for ocean image synthesis and surface wave analysis have been implemented with a dedicated radar processor to significantly reduce Synthetic Aperture Radar (SAR) ocean data before transmission to the ground. The object was to archive the SAR image spectrum, rather than the SAR image itself, to reduce data volume and capture the essential descriptors of the surface wave field. SAR signal data are usually sampled and coded in the time domain for transmission to the ground where Fourier Transforms are applied both to individual radar pulses and to long sequences of radar pulses to form two-dimensional images. High resolution images of the ocean often contain no striking features and subtle image modulations by wind generated surface waves are only apparent when large ocean regions are studied, with Fourier transforms, to reveal periodic patterns created by wind stress over the surface wave field. Major ocean currents and atmospheric instability in coastal environments are apparent as large scale modulations of SAR imagery. This paper explores the possibility of computing complex Fourier spectrum codes representing SAR images, transmitting the coded spectra to Earth for data archives and creating scenes of surface wave signatures and air-sea interactions via inverse Fourier transformations with ground station processors.

Spotlight SAR interferometry for terrain elevation mapping and interferometric change detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eichel, P.H.; Ghiglia, D.C.; Jakowatz, C.V. Jr.

1996-02-01

In this report, we employ an approach quite different from any previous work; we show that a new methodology leads to a simpler and clearer understanding of the fundamental principles of SAR interferometry. This methodology also allows implementation of an important collection mode that has not been demonstrated to date. Specifically, we introduce the following six new concepts for the processing of interferometric SAR (INSAR) data: (1) processing using spotlight mode SAR imaging (allowing ultra-high resolution), as opposed to conventional strip-mapping techniques; (2) derivation of the collection geometry constraints required to avoid decorrelation effects in two-pass INSAR; (3) derivation ofmore » maximum likelihood estimators for phase difference and the change parameter employed in interferometric change detection (ICD); (4) processing for the two-pass case wherein the platform ground tracks make a large crossing angle; (5) a robust least-squares method for two-dimensional phase unwrapping formulated as a solution to Poisson`s equation, instead of using traditional path-following techniques; and (6) the existence of a simple linear scale factor that relates phase differences between two SAR images to terrain height. We show both theoretical analysis, as well as numerous examples that employ real SAR collections to demonstrate the innovations listed above.« less

Synergistic use of optical and InSAR data for urban impervious surface mapping: A case study in Hong Kong

USGS Publications Warehouse

Jiang, L.; Liao, M.; Lin, H.; Yang, L.

2009-01-01

A wide range of urban ecosystem studies, including urban hydrology, urban climate, land use planning and watershed resource management, require accurate and up‐to‐date geospatial data of urban impervious surfaces. In this study, the potential of the synergistic use of optical and InSAR data in urban impervious surface mapping at the sub‐pixel level was investigated. A case study in Hong Kong was conducted for this purpose by applying a classification and regression tree (CART) algorithm to SPOT 5 multispectral imagery and ERS‐2 SAR data. Validated by reference data derived from high‐resolution colour‐infrared (CIR) aerial photographs, our results show that the addition of InSAR feature information can improve the estimation of impervious surface percentage (ISP) in comparison with using SPOT imagery alone. The improvement is especially notable in separating urban impervious surface from the vacant land/bare ground, which has been a difficult task in ISP modelling with optical remote sensing data. In addition, the results demonstrate the potential to map urban impervious surface by using InSAR data alone. This allows frequent monitoring of world's cities located in cloud‐prone and rainy areas.

Final Report (O1-ERD-051) Dynamic InSAR: Imaging Seismic Waves Remotely from Space

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vincent, P; Rodgers, A; Dodge, D

2003-02-07

The purpose of this LDRD project was to determine the feasibility of using InSAR (interferometric synthetic aperture radar) to image seismic waves remotely from space. If shown to be feasible, the long-term goal of this project would be to influence future SAR satellite missions and airborne SAR platforms to include a this new capability. This final report summarizes the accomplishments of the originally-planned 2-year project that was cut short to 1 year plus 2 months due to a funding priority change that occurred in the aftermath of the September 11th tragedy. The LDRD-ER project ''Dynamic InSAR: Imaging Seismic Waves frommore » Space'' (01-ERD-051) began in October, (FY01) and ended in December (FY02). Consequently, most of the results and conclusions for this project are represented in the FY0l Annual Report. Nonetheless, additional conclusions and insights regarding the progress of this work are included in this report. In should be noted that this work was restarted and received additional funding under the NA-22 DOE Nonproliferation Program in FY03.« less

Spatiotemporal deformation patterns of the Lake Urmia Causeway as characterized by multisensor InSAR analysis.

PubMed

Karimzadeh, Sadra; Matsuoka, Masashi; Ogushi, Fumitaka

2018-04-03

We present deformation patterns in the Lake Urmia Causeway (LUC) in NW Iran based on data collected from four SAR sensors in the form of interferometric synthetic aperture radar (InSAR) time series. Sixty-eight images from Envisat (2004-2008), ALOS-1 (2006-2010), TerraSAR-X (2012-2013) and Sentinel-1 (2015-2017) were acquired, and 227 filtered interferograms were generated using the small baseline subset (SBAS) technique. The rate of line-of-sight (LOS) subsidence of the LUC peaked at 90 mm/year between 2012 and 2013, mainly due to the loss of most of the water in Lake Urmia. Principal component analysis (PCA) was conducted on 200 randomly selected time series of the LUC, and the results are presented in the form of the three major components. The InSAR scores obtained from the PCA were used in a hydro-thermal model to investigate the dynamics of consolidation settlement along the LUC based on detrended water level and temperature data. The results can be used to establish a geodetic network around the LUC to identify more detailed deformation patterns and to help plan future efforts to reduce the possible costs of damage.

Combined cGPS and InSAR time series for observing subsidence in the southern Central Valley due to groundwater exploitation

NASA Astrophysics Data System (ADS)

Neely, W.; Borsa, A. A.; Silverii, F.

2017-12-01

Recent droughts have increased reliance on groundwater for agricultural production in California's Central Valley. Using Interferometric Synthetic Aperture Radar (InSAR), we observe upwards of 25 cm/yr of subsidence from November 2014 to February 2017 due to intense pumping. However, these observations are contaminated by atmospheric noise and orbital errors. We present a novel method for correcting long wavelength errors in InSAR deformation estimates using time series from continuous Global Positioning System (cGPS) stations within the SAR footprint, which we apply to C-band data from the Sentinel mission. We test our method using 49 SAR acquisitions from the Sentinel 1 satellites and 107 cGPS times series from the Geodesy Advancing Geoscience and EarthScope (GAGE) network in southern Central Valley. We correct each interferogram separately, implementing an intermittent Small Baseline Subset (ISBAS) technique to produce a time series of line-of-sight surface motion from 276 InSAR pairs. To estimate the vertical component of this motion, we remove horizontal tectonic displacements predicted by the Southern California Earthquake Center's (SCEC) Community Geodetic Model. We validate our method by comparing the corrected InSAR results with independent cGPS data and find a marked improvement in agreement between the two data sets, particularly in the deformation rates. Using this technique, we characterize the time evolution of surface vertical deformation in the southern Central Valley related to human exploitation of local groundwater resources. This methodology is applicable to data from other SAR satellites, including ALOS-2 and the upcoming US-India NISAR mission.

TerraSAR-X mission

NASA Astrophysics Data System (ADS)

Werninghaus, Rolf

2004-01-01

The TerraSAR-X is a German national SAR- satellite system for scientific and commercial applications. It is the continuation of the scientifically and technologically successful radar missions X-SAR (1994) and SRTM (2000) and will bring the national technology developments DESA and TOPAS into operational use. The space segment of TerraSAR-X is an advanced high-resolution X-Band radar satellite. The system design is based on a sound market analysis performed by Infoterra. The TerraSAR-X features an advanced high-resolution X-Band Synthetic Aperture Radar based on the active phased array technology which allows the operation in Spotlight-, Stripmap- and ScanSAR Mode with various polarizations. It combines the ability to acquire high resolution images for detailed analysis as well as wide swath images for overview applications. In addition, experimental modes like the Dual Receive Antenna Mode allow for full-polarimetric imaging as well as along track interferometry, i.e. moving target identification. The Ground Segment is optimized for flexible response to (scientific and commercial) User requests and fast image product turn-around times. The TerraSAR-X mission will serve two main goals. The first goal is to provide the strongly supportive scientific community with multi-mode X-Band SAR data. The broad spectrum of scientific application areas include Hydrology, Geology, Climatology, Oceanography, Environmental Monitoring and Disaster Monitoring as well as Cartography (DEM Generation) and Interferometry. The second goal is the establishment of a commercial EO-market in Europe which is driven by Infoterra. The commercial goal is the development of a sustainable EO-business so that the e.g. follow-on systems can be completely financed by industry from the profit. Due to its commercial potential, the TerraSAR-X project will be implemented based on a public-private partnership with the Astrium GmbH. This paper will describe first the mission objectives as well as the project organisation and major milestones. Then an overview on the satellite as well as the SAR instrument is given followed by a description of the system design. Finally the principle layout of the TerraSAR-X Ground Segment and some remarks on the European context are presented.

Making Mosaics Of SAR Imagery

NASA Technical Reports Server (NTRS)

Curlander, John C.; Kwok, Ronald; Pang, Shirley S.; Pang, Amy A.

1990-01-01

Spaceborne synthetic-aperture-radar (SAR) images useful for mapping of planets and investigations in Earth sciences. Produces multiframe mosaic by combining images along ground track, in adjacent cross-track swaths, or in ascending and descending passes. Images registered with geocoded maps such as ones produced by MAPJTC (NPO-17718), required as input. Minimal intervention by operator required. MOSK implemented on DEC VAX 11/785 computer running VMS 4.5. Most subroutines in FORTRAN, but three in MAXL and one in APAL.

L-band InSAR Penetration Depth Experiment, North Slope Alaska

NASA Astrophysics Data System (ADS)

Muskett, R. R.

2017-12-01

Since the first spacecraft-based synthetic aperture radar (SAR) mission NASA's SEASAT in 1978 radars have been flown in Low Earth Orbit (LEO) by other national space agencies including the Canadian Space Agency, European Space Agency, India Space Research Organization and the Japanese Aerospace Exploration Agency. Improvements in electronics, miniaturization and production have allowed for the deployment of SAR systems on aircraft for usage in agriculture, hazards assessment, land-use management and planning, meteorology, oceanography and surveillance. LEO SAR systems still provide a range of needful and timely information on large and small-scale weather conditions like those found across the Arctic where ground-base weather radars currently provide limited coverage. For investigators of solid-earth deformation attention must be given to the atmosphere on Interferometric SAR (InSAR) by aircraft and spacecraft multi-pass operations. Because radar has the capability to penetrate earth materials at frequencies from the P- to X-band attention must be given to the frequency dependent penetration depth and volume scattering. This is the focus of our new research project: to test the penetration depth of L-band SAR/InSAR by aircraft and spacecraft systems at a test site in Arctic Alaska using multi-frequency analysis and progressive burial of radar mesh-reflectors at measured depths below tundra while monitoring environmental conditions. Knowledge of the L-band penetration depth on lowland Arctic tundra is necessary to constrain analysis of carbon mass balance and hazardous conditions arising form permafrost degradation and thaw, surface heave and subsidence and thermokarst formation at local and regional scales. Ref.: Geoscience and Environment Protection, vol. 5, no. 3, p. 14-30, 2017. DOI: 10.4236/gep.2017.53002.

Satellite Radar Interferometry For Risk Management Of Gas Pipeline Networks

NASA Astrophysics Data System (ADS)

Ianoschi, Raluca; Schouten, Mathijs; Bas Leezenberg, Pieter; Dheenathayalan, Prabu; Hanssen, Ramon

2013-12-01

InSAR time series analyses can be fine-tuned for specific applications, yielding a potential increase in benchmark density, precision and reliability. Here we demonstrate the algorithms developed for gas pipeline monitoring, enabling operators to precisely pinpoint unstable locations. This helps asset management in planning, prioritizing and focusing in-situ inspections, thus reducing maintenance costs. In unconsolidated Quaternary soils, ground settlement contributes to possible failure of brittle cast iron gas pipes and their connections to houses. Other risk factors include the age and material of the pipe. The soil dynamics have led to a catastrophic explosion in the city of Amsterdam, which triggered an increased awareness for the significance of this problem. As the extent of the networks can be very wide, InSAR is shown to be a valuable source of information for identifying the hazard regions. We monitor subsidence affecting an urban gas transportation network in the Netherlands using both medium and high resolution SAR data. Results for the 2003-2010 period provide clear insights on the differential subsidence rates in the area. This enables characterization of underground motion that affects the integrity of the pipeline. High resolution SAR data add extra detail of door-to-door pipeline connections, which are vulnerable due to different settlements between house connections and main pipelines. The rates which we measure represent important input in planning of maintenance works. Managers can decide the priority and timing for inspecting the pipelines. The service helps manage the risk and reduce operational cost in gas transportation networks.

Ice Velocity Mapping in Antarctica - Towards a Virtual Satellite Constellation

NASA Astrophysics Data System (ADS)

Scheuchl, B.; Mouginot, J.; Rignot, E. J.; Crevier, Y.

2013-12-01

Ice sheets are acknowledged by the World Meteorological Organization (WMO) and the United Nations Framework Convention on Climate Change (UNFCCC) as an Essential Climate Variable (ECV) needed to make significant progress in the generation of global climate products and derived information. Ice velocity is a crucial geophysical parameter that can be measured using spaceborne Synthetic Aperture Radar (SAR) data. Here, we report on an update to available Earth System Data Records (ESDR) of ice velocity in Antarctica based on data from a suite of spaceborne (SAR) sensors and provide an overview on international coordination in an effort to best utilize the available SAR satellites. Building on the first complete mapping of the flow of ice surface over the Antarctic continent using data predominantly acquired during IPY, we are working on a series of regional studies analyzing data from several different epochs. The analysis of velocity changes between discrete measurements requires even more careful data processing in order to be able to accurately measure subtle changes. Examples for Larsen-C and the Amundsen Sea Embayment will be presented. Data continuity is a crucial aspect to this work, particularly in light of the fact that 4 SAR missions have ceased operations since IPY and all available missions have a primary mandate that is not scientific data collection. Following the successful internationally coordinated SAR data acquisitions over ice sheets during the International Polar Year 2007/2008, efforts are undertaken to continue data acquisitions in the spirit of collaboration. The Polar Space Task Group (PSTG) is succeeding the IPY coordinating body of international space agencies, Space Task Group (STG). The PSTG SAR Coordination Working Group was created to address the issue of SAR data acquisitions in the cryosphere. A review of ice sheet requirements was undertaken by the science community, presented to PSTG, and followed up with a set of sensor specific recommendations. PSTG includes this information in coordinated acquisition planning going forward. In 2013 the Canadian Space Agency committed RADARSAT-2 to a large scale Antarctic data acquisition campaign. This effort will be supported in the near future by the European Space Agency and the Japan Space Exploration Agency once Sentinel-1 and ALOS-2 are launched. In addition, the German Space Agency and the Italian Space Agency acquire high resolution SAR data in high priority sites. We provide an overview of high-level plans and show first results from the RADARSAT-2 campaign. Data analysis and ESDR production is conducted at the Department of Earth System Science, University of California Irvine under a contract with the National Aeronautics and Space Administration's MEaSUREs program. Spaceborne SAR data are made available courtesy of the Polar Space Task Group.

Unsupervised SBAS-DInSAR Processing of Space-borne SAR data for Earth Surface Displacement Time Series Generation

NASA Astrophysics Data System (ADS)

Casu, F.; de Luca, C.; Lanari, R.; Manunta, M.; Zinno, I.

2016-12-01

During the last 25 years, the Differential Synthetic Aperture Radar Interferometry (DInSAR) has played an important role for understanding the Earth's surface deformation and its dynamics. In particular, the large collections of SAR data acquired by a number of space-borne missions (ERS, ENVISAT, ALOS, RADARSAT, TerraSAR-X, COSMO-SkyMed) have pushed toward the development of advanced DInSAR techniques for monitoring the temporal evolution of the ground displacements with an high spatial density. Moreover, the advent of the Copernicus Sentinel-1 (S1) constellation is providing a further increase in the SAR data flow available to the Earth science community, due to its characteristics of global coverage strategy and free and open access data policy. Therefore, managing and storing such a huge amount of data, processing it in an effcient way and maximizing the available archives exploitation are becoming high priority issues. In this work we present some recent advances in the DInSAR field for dealing with the effective exploitation of the present and future SAR data archives. In particular, an efficient parallel SBAS implementation (namely P-SBAS) that takes benefit from high performance computing is proposed. Then, the P-SBAS migration to the emerging Cloud Computing paradigm is shown, together with extensive tests carried out in the Amazon's Elastic Cloud Compute (EC2) infrastructure. Finally, the integration of the P-SBAS processing chain within the ESA Geohazards Exploitation Platform (GEP), for setting up operational on-demand and systematic web tools, open to every user, aimed at automatically processing stacks of SAR data for the generation of SBAS displacement time series, is also illustrated. A number of experimental results obtained by using the ERS, ENVISAT and S1 data in areas characterized by volcanic, seismic and anthropogenic phenomena will be shown. This work is partially supported by: the DPC-CNR agreement, the EPOS-IP project and the ESA GEP project.

Compact time- and space-integrating SAR processor: design and development status

NASA Astrophysics Data System (ADS)

Haney, Michael W.; Levy, James J.; Christensen, Marc P.; Michael, Robert R., Jr.; Mock, Michael M.

1994-06-01

Progress toward a flight demonstration of the acousto-optic time- and space- integrating real-time SAR image formation processor program is reported. The concept overcomes the size and power consumption limitations of electronic approaches by using compact, rugged, and low-power analog optical signal processing techniques for the most computationally taxing portions of the SAR imaging problem. Flexibility and performance are maintained by the use of digital electronics for the critical low-complexity filter generation and output image processing functions. The results reported include tests of a laboratory version of the concept, a description of the compact optical design that will be implemented, and an overview of the electronic interface and controller modules of the flight-test system.

Monitoring landslide-induced deformation with TerraSAR-X Persistent Scatterer Interferometry (PSI): Gimigliano case study in Calabria Region (Italy)

NASA Astrophysics Data System (ADS)

Bianchini, S.; Cigna, F.; Del Ventisette, C.; Moretti, S.; Casagli, N.

2012-04-01

Landslide phenomena represent a major geological hazard worldwide, threatening human lives and settlements, especially in urban areas where the potential socio-economic losses and damages are stronger because of the higher value of the element at risk exposure and vulnerability. The impact of these natural disasters in highly populated and vulnerable areas can be reduced or prevented by performing a proper detection of such ground movements, in order to support an appropriate urban planning. Mapping and monitoring of active landslides and vulnerable slopes can greatly benefit from radar satellite data analysis, due to the great cost-benefits ratio, non-invasiveness and high precision of remote sensing techniques. This work illustrates the potential of Persistent Scatterer Interferometry (PSI) using X-band SAR (Synthetic Aperture Radar) data for a detailed detection and characterization of landslide ground displacements at local scale. PSI analysis is a powerful tool for mapping and monitoring slow surface displacements, just particularly in built-up and urbanized areas where many radar benchmarks (the PS, Persistent Scatterers) are retrieved. We exploit X-band radar data acquired from the German satellite TerraSAR-X on Gimigliano site located in Calabria Region (Italy). The use of TerraSAR-X imagery significantly improves the level of detail of the analysis and extends the applicability of space-borne SAR interferometry to faster ground movements, due to higher spatial resolutions (up to 1 m), higher PS targets density and shorter repeat cycles (11 days) of X-band satellites with respect to the medium resolution SAR sensors, such as ERS1/2, ENVISAT and RADARSAT1/2. 27 SAR scenes were acquired over a 116.9 Km2 extended area from the satellite TerraSAR-X in Spotlight mode, along descending orbits, with a look angle of 34°, from November 2010 to October 2011. The images were processed by e-GEOS with the Persistent Scatterers Pairs (PSP) technique, providing the estimation of annual velocities of LOS (Line Of Sight) ground displacements and related deformation time series for the whole acquisition period. The methodology performed is based on the integration of recent radar PS data in X-band with historical SAR archives derived from ERS1/2 and ENVISAT data in C-band, and with geological and geomorphological evidences resulting from the existing auxiliary data (e.g. landslide databases, thematic maps and aerial orthophotos), finally validated with field checks and in situ observations in the study area. This operative procedure led to the detailed study of the spatial distribution and temporal evolution of ground movements phenomena in Gimigliano site. The outcomes of this work represent a valuable example of detection and characterization of landslide-induced phenomena identified in detail by PSI analysis in X-band at local scale. This approach showed that PSI technique has the potential to improve the quality and timeliness of landslide inventories and consequently help for the implementation of best strategies for risk mitigation and urban-environmental design. This work was carried out within the SAFER (Services and Applications For Emergency Response) project, funded by the European Commission within the 7th Framework Programme under the Global Monitoring for Environment and Security (EC GMES FP7) initiative.

A nation-wide system for landslide mapping and risk management in Italy: The second Not-ordinary Plan of Environmental Remote Sensing

NASA Astrophysics Data System (ADS)

Di Martire, D.; Paci, M.; Confuorto, P.; Costabile, S.; Guastaferro, F.; Verta, A.; Calcaterra, D.

2017-12-01

Landslides are frequent events that may cause human casualties and injuries as well as damage to urban and man-made structures, with extensive loss of economic resources. For this reason, landslide mapping is a primary tool for hazard and risk assessment. Italian Ministry of Environment, thanks to great availability and functionality of Synthetic Aperture Radar (SAR) data promoted the Not-ordinary Plan of Environmental Remote Sensing (Piano Straordinario di Telerilevamento Ambientale, PST-A in Italian) in 2008, as to constitute a national database of active or potential instability phenomena affecting the Italian territory, based on the exploitation of interferometric products (ERS and ENVISAT). In this paper, the PST-A-3 is described. A procedure based on the integration of engineering-geological approaches and SAR interferometry data belonging to COSMO-SkyMed constellation (100 frames 40 × 40 km) has been here implemented over 7,400 km2 of the Italian territory. First, landslides have been mapped by field geologists, defining type and state of activity. Simultaneously to field surveys, remote sensing data have been analyzed as to detect areas with considerable displacement registered by the satellite. Both products have been overlaid, also quantifying the coincidence between the events reported according to the two detection methodologies and subtracting those landslide not recordable by the satellite, finally obtaining an updated landslide inventory map with 4,522 newly detected phenomena. Therefore, PST-A-3 proves to be a valuable system for local authorities, in order to provide a contribution to risk management but also for the forecasting of landslide events, as testified by two case studies selected. Thanks to the PST-A experience, the use of such strategy to other countries could represent a valid contribution to land management at worldwide scale.

Safety Assessment for a Surface Repository in the Chernobyl Exclusion Zone - Methodology for Assessing Disposal under Intervention Conditions - 13476

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haverkamp, B.; Krone, J.; Shybetskyi, I.

The Radioactive Waste Disposal Facility (RWDF) Buryakovka was constructed in 1986 as part of the intervention measures after the accident at Chernobyl NPP (ChNPP). Today, RWDF Buryakovka is still being operated but its maximum capacity is nearly reached. Plans for enlargement of the facility exist since more than 10 years but have not been implemented yet. In the framework of an European Commission Project DBE Technology GmbH prepared a safety analysis report of the facility in its current state (SAR) and a preliminary safety analysis report (PSAR) based on the planned enlargement. Due to its history RWDF Buryakovka does notmore » fully comply with today's best international practices and the latest Ukrainian regulations in this area. The most critical aspects are its inventory of long-lived radionuclides, and the non-existent multi-barrier waste confinement system. A significant part of the project was dedicated, therefore, to the development of a methodology for the safety assessment taking into consideration the facility's special situation and to reach an agreement with all stakeholders involved in the later review and approval procedure of the safety analysis reports. Main aspect of the agreed methodology was to analyze the safety, not strictly based on regulatory requirements but on the assessment of the actual situation of the facility including its location within the Exclusion Zone. For both safety analysis reports, SAR and PSAR, the assessment of the long-term safety led to results that were either within regulatory limits or within the limits allowing for a specific situational evaluation by the regulator. (authors)« less

Synthetic aperture radar signal data compression using block adaptive quantization

NASA Technical Reports Server (NTRS)

Kuduvalli, Gopinath; Dutkiewicz, Melanie; Cumming, Ian

1994-01-01

This paper describes the design and testing of an on-board SAR signal data compression algorithm for ESA's ENVISAT satellite. The Block Adaptive Quantization (BAQ) algorithm was selected, and optimized for the various operational modes of the ASAR instrument. A flexible BAQ scheme was developed which allows a selection of compression ratio/image quality trade-offs. Test results show the high quality of the SAR images processed from the reconstructed signal data, and the feasibility of on-board implementation using a single ASIC.

Application of SIR-C SAR to Hydrology

NASA Technical Reports Server (NTRS)

Engman, Edwin T.; ONeill, Peggy; Wood, Eric; Pauwels, Valentine; Hsu, Ann; Jackson, Tom; Shi, J. C.; Prietzsch, Corinna

1996-01-01

The progress, results and future plans regarding the following objectives are presented: (1) Determine and compare soil moisture patterns within one or more humid watersheds using SAR data, ground-based measurements, and hydrologic modeling; (2) Use radar data to characterize the hydrologic regime within a catchment and to identify the runoff producing characteristics of humid zone watersheds; and (3) Use radar data as the basis for scaling up from small scale, near-point process models to larger scale water balance models necessary to define and quantify the land phase of GCM's (Global Circulation Models).

CryoSat Plus for Oceans - analysis of the state-of-the-art

NASA Astrophysics Data System (ADS)

Naeije, Marc; Gommenginger, Christine; Moreau, Thomas; Cotton, David; Benveniste, Jerome; Dinardo Dinardo, Salvatore

2013-04-01

The CryoSat Plus for Oceans (CP4O) project is an ESA initiative carried out by a European wide consortium of altimetry experts. It aims to build a sound scientific basis for new scientific and operational applications of data coming from CryoSat-2 over the open ocean, polar ocean, coastal seas and for seafloor mapping. It also generates and evaluates new methods and products that will enable the full exploitation of the capabilities of the CryoSat-2 SIRAL altimeter, and extend their application beyond the initial mission objectives. It therefore also acts as a preparation for the upcoming Sentinel and Jason SAR enabled altimetry missions. In this paper we address the review of the CryoSat state-of-the-art, relevant current initiatives, algorithms, models and Earth Observation based products and datasets that are relevant in the Cryosat+ ocean theme. Compared to conventional (pulse-limited) altimeter missions, Cryosat-2 is not a dedicated platform for ocean research: typically the microwave radiometer (MWR) for wet tropospheric corrections is lacking, as is the direct measurement of the first order ionospheric effect by means of a dual-frequency altimeter. Also the orbit of Cryosat-2 has a rather long repetition period, unsuited for collinear tracks analyses. These three particular features have been studied already in the HERACLES project on the eve of the first CryoSat launch. We revisit the outcome of this study, update to current understanding and perception, and ultimately develop what was, is and will be proposed in these problem areas. Clearly, we question the standard ionosphere corrections, the wet troposphere corrections and the accuracy of the mean sea surface (MSS) underlying the accuracy of derived sea level anomalies. In addition, Cryosat-2 provides the first innovative altimeter with SAR and SARIn modes. This raises the direct problem of "how to process these data", simply because this has not been done before. Compared to pulse-limited altimetry it is a totally different branch of sport. In our CP4O project we try to answer this. We build on the results that have come out of the SAMOSA study, which was initiated to investigate the improvements that SAR mode altimetry can offer in measurements over ocean, coastal and inland water surfaces, developing practical implementation of new theoretical models for the SAR echo waveform. It is clear that having specific processing for SAR and SARIn raises a number of new issues to be studied, such as RDSAR (reducing SAR to pseudo LRM data), sea state bias (SSB) in SAR mode, and land contamination, to name a few. The outcome of the analysis of the state-of-the-art culminates in the delivery of the Preliminary Analysis Report and the Development and Validation Plan (DVP). We present the summary of these documents.

76 FR 79114 - Privacy Act of 1974: Implementation of Exemptions; DOT/ALL 23-Information Sharing Environment...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-21

...] Privacy Act of 1974: Implementation of Exemptions; DOT/ALL 23-- Information Sharing Environment (ISE... titled, ``DOT/ALL 23--Information Sharing Environment (ISE) Suspicious Activity Reporting (SAR... exempts portions of the ``DOT/ALL 23--Information Sharing Environment (ISE) Suspicious Activity Reporting...

Behind the mask. Journey through an epidemic: some observations of contrasting public health responses to SARS

PubMed Central

Syed, Q; Sopwith, W; Regan, M; Bellis, M

2003-01-01

SARS has been called the first global epidemic of the 21st century and has been the cause of a massive and varied public health response in many countries of the world. This report describes observations made by two authors on a journey from Manchester in the United Kingdom to Chiang Mai in Thailand during the peak of global transmission. The public response to SARS, particularly characterised by the wearing of face masks, seemed to outstrip official guidance. Though of uncertain protective benefit, the wearing of masks may have contributed to the awareness of the collective and personal responsibility in combating infectious disease. Active and empowered involvement of the general public in implementing and cooperating with public health control measures supported by national and international authorities has clearly helped to bring SARS under control. The public health significance of such potent symbols as the face mask may be considered in strategies to tackle other emerging infections. PMID:14600109

Development and Implementation for Calculation Model of Measuring Co-Seismic Deformation Field by Using Ascending and Descending Orbit SAR Data

NASA Astrophysics Data System (ADS)

Xue, Tengfei; Chang, Zhanqiang; Zhang, Jingfa

2016-08-01

Interferometry Synthetic Aperture Radar (InSAR)can only measure one component of the surface deformation in the satellite's line of sight (LOS) instead of that in vertical and horizontal directions, i.e. LOS Amphibious. In view of this problem, we analyzed and summarized some methods that can measure the three-dimensional deformation of ground surface by using D-InSAR, developed the calculation model of measuring the three-dimensional co-seismic deformation filed by using the ascending and descending orbit SAR data. The Formula of left-looking (both ascending and descending orbit data), right-looking (both ascending and descending orbit data) and general expression were proposed. The model was applied on L'Aquila earthquake, and the results reveal that the earthquake has caused displacement in both vertical and horizontal directions, and the earthquake made the area down lift 16.8cm along the vertical direction. The characters of the surface reflected by the results are very consistent with the geological exploration.

17 CFR 270.8b-16 - Amendments to registration statement.

Code of Federal Regulations, 2012 CFR

2012-04-01

... on Form N-SAR, as prescribed by rule 30b1-1 (17 CFR 270.30b1-1), shall amend the registration... information is transmitted to shareholders in its annual report to shareholders: (1) If the company offers a dividend reinvestment plan to shareholders, information about the plan required to be disclosed in the...

17 CFR 270.8b-16 - Amendments to registration statement.

Code of Federal Regulations, 2013 CFR

2013-04-01

... on Form N-SAR, as prescribed by rule 30b1-1 (17 CFR 270.30b1-1), shall amend the registration... information is transmitted to shareholders in its annual report to shareholders: (1) If the company offers a dividend reinvestment plan to shareholders, information about the plan required to be disclosed in the...

17 CFR 270.8b-16 - Amendments to registration statement.

Code of Federal Regulations, 2014 CFR

2014-04-01

... on Form N-SAR, as prescribed by rule 30b1-1 (17 CFR 270.30b1-1), shall amend the registration... information is transmitted to shareholders in its annual report to shareholders: (1) If the company offers a dividend reinvestment plan to shareholders, information about the plan required to be disclosed in the...

17 CFR 270.8b-16 - Amendments to registration statement.

Code of Federal Regulations, 2011 CFR

2011-04-01

... on Form N-SAR, as prescribed by rule 30b1-1 (17 CFR 270.30b1-1), shall amend the registration... information is transmitted to shareholders in its annual report to shareholders: (1) If the company offers a dividend reinvestment plan to shareholders, information about the plan required to be disclosed in the...

A suggestion for computing objective function in model calibration

USGS Publications Warehouse

Wu, Yiping; Liu, Shuguang

2014-01-01

A parameter-optimization process (model calibration) is usually required for numerical model applications, which involves the use of an objective function to determine the model cost (model-data errors). The sum of square errors (SSR) has been widely adopted as the objective function in various optimization procedures. However, ‘square error’ calculation was found to be more sensitive to extreme or high values. Thus, we proposed that the sum of absolute errors (SAR) may be a better option than SSR for model calibration. To test this hypothesis, we used two case studies—a hydrological model calibration and a biogeochemical model calibration—to investigate the behavior of a group of potential objective functions: SSR, SAR, sum of squared relative deviation (SSRD), and sum of absolute relative deviation (SARD). Mathematical evaluation of model performance demonstrates that ‘absolute error’ (SAR and SARD) are superior to ‘square error’ (SSR and SSRD) in calculating objective function for model calibration, and SAR behaved the best (with the least error and highest efficiency). This study suggests that SSR might be overly used in real applications, and SAR may be a reasonable choice in common optimization implementations without emphasizing either high or low values (e.g., modeling for supporting resources management).

Ship Detection in Gaofen-3 SAR Images Based on Sea Clutter Distribution Analysis and Deep Convolutional Neural Network

PubMed Central

You, Hongjian

2018-01-01

Target detection is one of the important applications in the field of remote sensing. The Gaofen-3 (GF-3) Synthetic Aperture Radar (SAR) satellite launched by China is a powerful tool for maritime monitoring. This work aims at detecting ships in GF-3 SAR images using a new land masking strategy, the appropriate model for sea clutter and a neural network as the discrimination scheme. Firstly, the fully convolutional network (FCN) is applied to separate the sea from the land. Then, by analyzing the sea clutter distribution in GF-3 SAR images, we choose the probability distribution model of Constant False Alarm Rate (CFAR) detector from K-distribution, Gamma distribution and Rayleigh distribution based on a tradeoff between the sea clutter modeling accuracy and the computational complexity. Furthermore, in order to better implement CFAR detection, we also use truncated statistic (TS) as a preprocessing scheme and iterative censoring scheme (ICS) for boosting the performance of detector. Finally, we employ a neural network to re-examine the results as the discrimination stage. Experiment results on three GF-3 SAR images verify the effectiveness and efficiency of this approach. PMID:29364194

Ship Detection in Gaofen-3 SAR Images Based on Sea Clutter Distribution Analysis and Deep Convolutional Neural Network.

PubMed

An, Quanzhi; Pan, Zongxu; You, Hongjian

2018-01-24

Target detection is one of the important applications in the field of remote sensing. The Gaofen-3 (GF-3) Synthetic Aperture Radar (SAR) satellite launched by China is a powerful tool for maritime monitoring. This work aims at detecting ships in GF-3 SAR images using a new land masking strategy, the appropriate model for sea clutter and a neural network as the discrimination scheme. Firstly, the fully convolutional network (FCN) is applied to separate the sea from the land. Then, by analyzing the sea clutter distribution in GF-3 SAR images, we choose the probability distribution model of Constant False Alarm Rate (CFAR) detector from K-distribution, Gamma distribution and Rayleigh distribution based on a tradeoff between the sea clutter modeling accuracy and the computational complexity. Furthermore, in order to better implement CFAR detection, we also use truncated statistic (TS) as a preprocessing scheme and iterative censoring scheme (ICS) for boosting the performance of detector. Finally, we employ a neural network to re-examine the results as the discrimination stage. Experiment results on three GF-3 SAR images verify the effectiveness and efficiency of this approach.

Tectonic and volcanic monitoring using Sentinel-1: Current status and future plans of the COMET InSAR portal

NASA Astrophysics Data System (ADS)

Spaans, Karsten; Hatton, Emma; Gonzalez, Pablo; Walters, Richard; McDougall, Alistair; Wright, Tim; Hooper, Andy

2017-04-01

The advantages of the Sentinel-1 constellation for InSAR applications over previous radar missions are numerous, and include small baselines, a planned operation time of 20 years, continuous and systematic acquisition of data over tectonic and volcanic areas, near-global coverage of the earth and free data availability. In order to take advantage of these properties, we at the Centre for the Observation and Modelling of Earthquakes, Volcanoes, and Tectonics (COMET) are developing a system that routinely processes and freely distributes interferometric products and time series over tectonic and volcanic regions. This project, and similar efforts at other institutions, will be a game changer for the monitoring and studying of tectonic and volcanic activity using InSAR. Since December 2016, the COMET-LiCS InSAR portal (http://comet.nerc.ac.uk/COMET-LiCS-portal/) has been live, delivering interferograms and coherence estimates over the entire Alpine-Himalayan belt. The portal already contains tens of thousands of products, which can be browsed in a user-friendly portal, and downloaded for free by the general public. For our processing, we use the Climate and Environmental Monitoring from Space (CEMS) facility, where we have large storage and processing facilities to our disposal and a complete duplicate of the Sentinel-1 archive is maintained. This greatly simplifies the infrastructure we have had to develop for automated processing of large areas. Here we will give an overview of the current status of the processing system, as well as discuss future plans. We will cover the infrastructure we developed to automatically produce interferograms and its challenges, and the processing strategy for time series analysis. We will outline the objectives of the system in the near and distant future, and a roadmap for its continued development. Finally, we will highlight some of the scientific results and projects linked to the system.

Localized landslide risk assessment with multi pass L band DInSAR analysis

NASA Astrophysics Data System (ADS)

Yun, HyeWon; Rack Kim, Jung; Lin, Shih-Yuan; Choi, YunSoo

2014-05-01

In terms of data availability and error correction, landslide forecasting by Differential Interferometric SAR (DInSAR) analysis is not easy task. Especially, the landslides by the anthropogenic construction activities frequently occurred in the localized cutting side of mountainous area. In such circumstances, it is difficult to attain sufficient enough accuracy because of the external factors inducing the error component in electromagnetic wave propagation. For instance, the local climate characteristics such as orographic effect and the proximity to water source can produce the significant anomalies in the water vapor distribution and consequently result in the error components of InSAR phase angle measurements. Moreover the high altitude parts of target area cause the stratified tropospheric delay error in DInSAR measurement. The other obstacle in DInSAR observation over the potential landside site is the vegetation canopy which causes the decorrelation of InSAR phase. Thus rather than C band sensor such as ENVISAT, ERS and RADARSAT, DInSAR analysis with L band ALOS PLASAR is more recommendable. Together with the introduction of L band DInSAR analysis, the improved DInSAR technique to cope all above obstacles is necessary. Thus we employed two approaches i.e. StaMPS/MTI (Stanford Method for Persistent Scatterers/Multi-Temporal InSAR, Hopper et al., 2007) which was newly developed for extracting the reliable deformation values through time series analysis and two pass DInSAR with the error term compensation based on the external weather information in this study. Since the water vapor observation from spaceborne radiometer is not feasible by the temporal gap in this case, the quantities from weather Research Forecasting (WRF) with 1 km spatial resolution was used to address the atmospheric phase error in two pass DInSAR analysis. Also it was observed that base DEM offset with time dependent perpendicular baselines of InSAR time series produce a significant error even in the advanced time series techniques such as StaMPS/MTI. We tried to compensate with the algorithmic base together with the usage of high resolution LIDAR DEM. The target area of this study is the eastern part of Korean peninsula centered. In there, the landslide originated by the geomorphic factors such as high sloped topography and localized torrential down pour is critical issue. The surface deformations from error corrected two pass DInSAR and StaMPS/MTI are crossly compared and validated with the landslide triggering factors such as vegetation, slope and geological properties. The study will be further extended for the application of future SAR sensors by incorporating the dynamic analysis of topography to implement practical landslide forecasting scheme.

Application of asymmetric mapping and selective filtering (AM and SF) method to Cosmo/SkyMed images by implementation of a selective blocks approach for ship detection optimization in SEASAFE framework

NASA Astrophysics Data System (ADS)

Loreggia, D.; Tataranni, F.; Trivero, P.; Biamino, W.; Di Matteo, L.

2017-10-01

We present the implementation of a procedure to adapt an Asymmetric Wiener Filtering (AWF) methodology aimed to detect and discard ghost signal due to azimuth ambiguities in SAR images to the case for X-band Cosmo Sky Med (CSK) images in the framework of SEASAFE (Slick Emissions And Ship Automatic Features Extraction) project, developed at the Department of Science and Technology Innovation of the University of Piemonte Orientale, Alessandria, Italy. SAR is a useful tool to daily and nightly monitoring of the sea surface in all weather conditions. SEASAFE project is a software platform developed in IDL language able to process data in C- Land X-band SAR images with enhanced algorithm modules for land masking, sea pollution (oil spills) and ship detection; wind and wave evaluation are also available. In this contest, the need to individuate and discard false alarms is a critical requirement. The azimuth ambiguity is one of the main causes that generate false alarm in the ship detection procedure. Many methods to face with this problem were proposed and presented in recent literature. After a review of different approach to this problem, we describe the procedure to adapt the AWF approach presented in [1,2] to the case of X-band CSK images by implementing a selective blocks approach.

Impact of quarantine on the 2003 SARS outbreak: a retrospective modeling study.

PubMed

Hsieh, Ying-Hen; King, Chwan-Chuan; Chen, Cathy W S; Ho, Mei-Shang; Hsu, Sze-Bi; Wu, Yi-Chun

2007-02-21

During the 2003 Severe Acute Respiratory Syndrome (SARS) outbreak, traditional intervention measures such as quarantine and border control were found to be useful in containing the outbreak. We used laboratory verified SARS case data and the detailed quarantine data in Taiwan, where over 150,000 people were quarantined during the 2003 outbreak, to formulate a mathematical model which incorporates Level A quarantine (of potentially exposed contacts of suspected SARS patients) and Level B quarantine (of travelers arriving at borders from SARS affected areas) implemented in Taiwan during the outbreak. We obtain the average case fatality ratio and the daily quarantine rate for the Taiwan outbreak. Model simulations is utilized to show that Level A quarantine prevented approximately 461 additional SARS cases and 62 additional deaths, while the effect of Level B quarantine was comparatively minor, yielding only around 5% reduction of cases and deaths. The combined impact of the two levels of quarantine had reduced the case number and deaths by almost a half. The results demonstrate how modeling can be useful in qualitative evaluation of the impact of traditional intervention measures for newly emerging infectious diseases outbreak when there is inadequate information on the characteristics and clinical features of the new disease-measures which could become particularly important with the looming threat of global flu pandemic possibly caused by a novel mutating flu strain, including that of avian variety.

Coseismic Displacement Analysis of the 12 November 2017 MW 7.3 Sarpol-E Zahab (iran) Earthquake from SAR Interferometry, Burst Overlap Interferometry and Offset Tracking

NASA Astrophysics Data System (ADS)

Vajedian, Sanaz; Motagh, Mahdi

2018-04-01

Interferometric wide-swath mode of Sentinel-1, which is implemented by Terrain Observation by Progressive Scan (TOPS) technique, is the main mode of SAR data acquisition in this mission. It aims at global monitoring of large areas with enhanced revisit frequency of 6 days at the expense of reduced azimuth resolution, compared to classical ScanSAR mode. TOPS technique is equipped by steering the beam from backward to forward along the heading direction for each burst, in addition to the steering along the range direction, which is the only sweeping direction in standard ScanSAR mode. This leads to difficulty in measuring along-track displacement by applying the conventional method of multi-aperture interferometry (MAI), which exploits a double difference interferometry to estimate azimuth offset. There is a possibility to solve this issue by a technique called "Burst Overlap Interferometry" which focuses on the region of burst overlap. Taking advantage of large squint angle diversity of 1° in burst overlapped area leads to improve the accuracy of ground motion measurement especially in along-track direction. We investigate the advantage of SAR Interferometry (InSAR), burst overlap interferometry and offset tracking to investigate coseismic deformation and coseismic-induced landslide related to 12 November 2017 Mw 7.3 Sarpol-e Zahab earthquake in Iran.

Complex surface deformation monitoring and mechanism inversion over Qingxu-Jiaocheng, China with multi-sensor SAR images

NASA Astrophysics Data System (ADS)

Liu, Yuanyuan; Zhao, Chaoying; Zhang, Qin; Yang, Chengsheng

2018-02-01

Qingxu-Jiaocheng, China has been suffering severe land subsidence along with the development of ground fissure, which are controlled by local fault and triggered by groundwater withdrawal. With multi-sensor SAR images, we study the spatiotemporal evolution of ground deformation over Qingxu-Jiaocheng with an IPTA InSAR technique and assess the role of groundwater withdrawal to the observed deformation. Discrete GPS measurements are applied to verify the InSAR results. The RMSE of the differences between InSAR and GPS, i.e. ALOS and GPS and Envisat and GPS, are 5.7 mm and 6.3 mm in the LOS direction, respectively. The east-west and vertical components of the observed deformation from 2007 to 2010 are decomposed by using descending-track Envisat and ascending-track ALOS interferograms, indicating that the east-west component cannot be neglected when the deformation is large or the ground fissure is active. Four phases of land subsidence in the study region are successfully retrieved, and its spatiotemporal evolution is quantitatively analyzed. Lastly, a flat lying sill model with distributed contractions is implemented to model the InSAR deformation over Qingxu-Jiaocheng, which manifests that the ground deformation is mainly caused by groundwater withdrawal. This research provides new insights into the land subsidence monitoring and its mechanism inversion over Qingxu-Jiaocheng region.

An Assessment of Spaceborne Near-Nadir Interferometric SAR Performance Over Inland Waters with Real

NASA Astrophysics Data System (ADS)

Tan, H.; Li, S. Y.; Liu, Z. W.

2018-04-01

Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA), which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

Measuring grassland structure for recovery of grassland species at risk

NASA Astrophysics Data System (ADS)

Guo, Xulin; Gao, Wei; Wilmshurst, John

2005-09-01

An action plan for recovering species at risk (SAR) depends on an understanding of the plant community distribution, vegetation structure, quality of the food source and the impact of environmental factors such as climate change at large scale and disturbance at small scale, as these are fundamental factors for SAR habitat. Therefore, it is essential to advance our knowledge of understanding the SAR habitat distribution, habitat quality and dynamics, as well as developing an effective tool for measuring and monitoring SAR habitat changes. Using the advantages of non-destructive, low cost, and high efficient land surface vegetation biophysical parameter characterization, remote sensing is a potential tool for helping SAR recovery action. The main objective of this paper is to assess the most suitable techniques for using hyperspectral remote sensing to quantify grassland biophysical characteristics. The challenge of applying remote sensing in semi-arid and arid regions exists simply due to the lower biomass vegetation and high soil exposure. In conservation grasslands, this problem is enhanced because of the presence of senescent vegetation. Results from this study demonstrated that hyperspectral remote sensing could be the solution for semi-arid grassland remote sensing applications. Narrow band raw data and derived spectral vegetation indices showed stronger relationships with biophysical variables compared to the simulated broad band vegetation indices.

Assessing groundwater quality for irrigation using indicator kriging method

NASA Astrophysics Data System (ADS)

Delbari, Masoomeh; Amiri, Meysam; Motlagh, Masoud Bahraini

2016-11-01

One of the key parameters influencing sprinkler irrigation performance is water quality. In this study, the spatial variability of groundwater quality parameters (EC, SAR, Na+, Cl-, HCO3 - and pH) was investigated by geostatistical methods and the most suitable areas for implementation of sprinkler irrigation systems in terms of water quality are determined. The study was performed in Fasa county of Fars province using 91 water samples. Results indicated that all parameters are moderately to strongly spatially correlated over the study area. The spatial distribution of pH and HCO3 - was mapped using ordinary kriging. The probability of concentrations of EC, SAR, Na+ and Cl- exceeding a threshold limit in groundwater was obtained using indicator kriging (IK). The experimental indicator semivariograms were often fitted well by a spherical model for SAR, EC, Na+ and Cl-. For HCO3 - and pH, an exponential model was fitted to the experimental semivariograms. Probability maps showed that the risk of EC, SAR, Na+ and Cl- exceeding the given critical threshold is higher in lower half of the study area. The most proper agricultural lands for sprinkler irrigation implementation were identified by evaluating all probability maps. The suitable areas for sprinkler irrigation design were determined to be 25,240 hectares, which is about 34 percent of total agricultural lands and are located in northern and eastern parts. Overall the results of this study showed that IK is an appropriate approach for risk assessment of groundwater pollution, which is useful for a proper groundwater resources management.

Integration of multispectral and SAR data for monitoring forest ecosystems recovery after fire

NASA Astrophysics Data System (ADS)

Stankova, Nataliya; Nedkov, Roumen; Ivanova, Iva; Avetisyan, Daniela

2017-09-01

The aim of this study is assessing the impacts and monitoring the condition and recovery processes of forest ecosystems after fire based on remote aerospace methods and data. To achieve this goal, satellite imagery in microwave and optical range of the spectrum were used. A hybrid model for assessing the instantaneous condition of forest ecosystems after fire that uses parallel data from optical and Synthetic Aperture Radar (SAR) was developed. Based on the three Tasseled Cap components (Brightness-BR, Greenness-GR and Wetness-W), a vector describing the current condition of the forest ecosystems was obtained and used as input data from the optical range. Results obtained by implementation of the proposed approach show that the integrated composite images of VIC and SAR represent the degree of recovery.

The Born approximation, multiple scattering, and the butterfly algorithm

NASA Astrophysics Data System (ADS)

Martinez, Alejandro F.

Radar works by focusing a beam of light and seeing how long it takes to reflect. To see a large region the beam is pointed in different directions. The focus of the beam depends on the size of the antenna (called an aperture). Synthetic aperture radar (SAR) works by moving the antenna through some region of space. A fundamental assumption in SAR is that waves only bounce once. Several imaging algorithms have been designed using that assumption. The scattering process can be described by iterations of a badly behaving integral. Recently a method for efficiently evaluating these types of integrals has been developed. We will give a detailed implementation of this algorithm and apply it to study the multiple scattering effects in SAR using target estimates from single scattering algorithms.

Spaceborne SAR Data for Aboveground-Biomass Retrieval of Indian Tropical Forests

NASA Astrophysics Data System (ADS)

Khati, U.; Singh, G.; Musthafa, M.

2017-12-01

Forests are important and indispensable part of the terrestrial ecosystems, and have a direct impact on the global carbon cycle. Forest biophysical parameters such as forest stand height and forest above-ground biomass (AGB) are forest health indicators. Measuring the forest biomass using traditional ground survey techniques are man-power consuming and have very low spatial coverage. Satellite based remote sensing techniques provide synoptic view of the earth with continuous measurements over large, inaccessible forest regions. Satellite Synthetic Aperture Radar (SAR) data has been shown to be sensitive to these forest bio-physical parameters and have been extensively utilized over boreal and tropical forests. However, there are limited studies over Indian tropical forests due to lack of auxiliary airborne data and difficulties in manual in situ data collection. In this research work we utilize spaceborne data from TerraSAR-X/TanDEM-X and ALOS-2/PALSAR-2 and implement both Polarimetric SAR and PolInSAR techniques for retrieval of AGB of a managed tropical forest in India. The TerraSAR-X/TanDEM-X provide a single-baseline PolInSAR data robust to temporal decorrelation. This would be used to accurately estimate the forest stand height. The retrieved height would be an input parameter for modelling AGB using the L-band ALOS-2/PALSAR-2 data. The IWCM model is extensively utilized to estimate AGB from SAR observations. In this research we utilize the six component scattering power decomposition (6SD) parameters and modify the IWCM based technique for a better retrieval of forest AGB. PolInSAR data shows a high estimation accuracy with r2 of 0.8 and a RMSE of 2 m. With this accurate height provided as input to the modified model along with 6SD parameters shows promising results. The results are validated with extensive field based measurements, and are further analysed in detail.

Monitoring forest carbon in a Tanzanian woodland using interferometric SAR: a novel methodology for REDD.

PubMed

Solberg, Svein; Gizachew, Belachew; Næsset, Erik; Gobakken, Terje; Bollandsås, Ole Martin; Mauya, Ernest William; Olsson, Håkan; Malimbwi, Rogers; Zahabu, Eliakimu

2015-12-01

REDD+ implementation requires establishment of a system for measuring, reporting and verification (MRV) of forest carbon changes. A challenge for MRV is the lack of satellite based methods that can track not only deforestation, but also degradation and forest growth, as well as a lack of historical data that can serve as a basis for a reference emission level. Working in a miombo woodland in Tanzania, we here aim at demonstrating a novel 3D satellite approach based on interferometric processing of radar imagery (InSAR). Forest carbon changes are derived from changes in the forest canopy height obtained from InSAR, i.e. decreases represent carbon loss from logging and increases represent carbon sequestration through forest growth. We fitted a model of above-ground biomass (AGB) against InSAR height, and used this to convert height changes to biomass and carbon changes. The relationship between AGB and InSAR height was weak, as the individual plots were widely scattered around the model fit. However, we consider the approach to be unique and feasible for large-scale MRV efforts in REDD+ because the low accuracy was attributable partly to small plots and other limitations in the data set, and partly to a random pixel-to-pixel variation in trunk forms. Further processing of the InSAR data provides data on the categories of forest change. The combination of InSAR data from the Shuttle RADAR Topography Mission (SRTM) and the TanDEM-X satellite mission provided both historic baseline of change for the period 2000-2011, as well as annual change 2011-2012. A 3D data set from InSAR is a promising tool for MRV in REDD+. The temporal changes seen by InSAR data corresponded well with, but largely supplemented, the changes derived from Landsat data.

Massive Cloud Computing Processing of P-SBAS Time Series for Displacement Analyses at Large Spatial Scale

NASA Astrophysics Data System (ADS)

Casu, F.; de Luca, C.; Lanari, R.; Manunta, M.; Zinno, I.

2016-12-01

A methodology for computing surface deformation time series and mean velocity maps of large areas is presented. Our approach relies on the availability of a multi-temporal set of Synthetic Aperture Radar (SAR) data collected from ascending and descending orbits over an area of interest, and also permits to estimate the vertical and horizontal (East-West) displacement components of the Earth's surface. The adopted methodology is based on an advanced Cloud Computing implementation of the Differential SAR Interferometry (DInSAR) Parallel Small Baseline Subset (P-SBAS) processing chain which allows the unsupervised processing of large SAR data volumes, from the raw data (level-0) imagery up to the generation of DInSAR time series and maps. The presented solution, which is highly scalable, has been tested on the ascending and descending ENVISAT SAR archives, which have been acquired over a large area of Southern California (US) that extends for about 90.000 km2. Such an input dataset has been processed in parallel by exploiting 280 computing nodes of the Amazon Web Services Cloud environment. Moreover, to produce the final mean deformation velocity maps of the vertical and East-West displacement components of the whole investigated area, we took also advantage of the information available from external GPS measurements that permit to account for possible regional trends not easily detectable by DInSAR and to refer the P-SBAS measurements to an external geodetic datum. The presented results clearly demonstrate the effectiveness of the proposed approach that paves the way to the extensive use of the available ERS and ENVISAT SAR data archives. Furthermore, the proposed methodology can be particularly suitable to deal with the very huge data flow provided by the Sentinel-1 constellation, thus permitting to extend the DInSAR analyses at a nearly global scale. This work is partially supported by: the DPC-CNR agreement, the EPOS-IP project and the ESA GEP project.

Development and Evaluation of Science and Technology Education Program Using Interferometric SAR

NASA Astrophysics Data System (ADS)

Ito, Y.; Ikemitsu, H.; Nango, K.

2016-06-01

This paper proposes a science and technology education program to teach junior high school students to measure terrain changes by using interferometric synthetic aperture radar (SAR). The objectives of the proposed program are to evaluate and use information technology by performing SAR data processing in order to measure ground deformation, and to incorporate an understanding of Earth sciences by analyzing interferometric SAR processing results. To draft the teaching guidance plan for the developed education program, this study considers both science and technology education. The education program was used in a Japanese junior high school. An educational SAR processor developed by the authors and the customized Delft object-oriented radar interferometric software package were employed. Earthquakes as diastrophism events were chosen as practical teaching materials. The selected events indicate clear ground deformation in differential interferograms with high coherence levels. The learners were able to investigate the ground deformations and disasters caused by the events. They interactively used computers and became skilled at recognizing the knowledge and techniques of information technology, and then they evaluated the technology. Based on the results of pre- and post-questionnaire surveys and self-evaluation by the learners, it was clarified that the proposed program was applicable for junior high school education, and the learners recognized the usefulness of Earth observation technology by using interferometric SAR. The usefulness of the teaching materials in the learning activities was also shown through the practical teaching experience.

Low cost realization of space-borne synthectic aperture radar - MicroSAR

NASA Astrophysics Data System (ADS)

Carter, D.; Hall, C.

Spaceborne Earth Observation data has been used for decades in the areas of meteorology and optical imaging. The systems and satellites have, in the main, been owned and operated by a few government institutions and agencies. More recently industrial organizations in North America have joined the list. Few of these, however, include Synthetic Aperture Radar (SAR)., although the additional utility in terms of all weather, 24 hour measurement capability over the Earth's surface is well recognized. Three major factors explain this:1) Relationships between the SAR measurements of radar backscatter and images to the specific information needs have not been seen as sufficiently well understood or robust2) Availability of suitable sources, at the relevant performance and data quality have been inadequate to provide service assurance that is necessary to sustain commercial businesses3) Costs associated with building, launching and operating spaceborne SAR have not been low enough as to achieve an acceptable return of investment. A significant amount of research and development has been undertaken throughout the World to establish reliable and robust algorithms for information extraction from SAR data. Much of this work has been carried out utilizing airborne systems over localized and carefully controlled regions. In addition, an increasing number of pilot services have been offered by geo-information providers. This has allowed customer confidence to grow. With the status of spaceborne SAR being effectively in the development phase, commercial funding has been scarce, and there has been need to rely on government and institutional budgets. Today the increasing maturity of the technology of SAR and its applications is beginning to attract the commercial sector. This is the funding necessary to realize sufficient assets to be able to provide a robust supply of SAR data to the geo-information providers and subsequently a reliable service to customers. Reducing the costs associated with implementing spaceborne SAR systems is an aspect of work that has been addressed over the past decade by the main S RA system expert companies. As the experimental systems have been realized and understood, so there has been a move to transfer these systems from the research and scientific domains into operational and commercial implementations. The end of the cold war, combined with the ever increasingly competitive telecommunications market, have assisted in driving down the launch costs, a significant cost element in any space system budget. To take maximum benefit from this it is still necessary to be able to make light weight satellites, in the region of 450 Kgs or less. Typically SAR satellites have been in the neighbourhood of 1.5 to 2.5 Tonnes. In order to achieve the low cost systems, not only the satellite mass needs to be tackled but also several other factors:- Design complexity- Production costs- Performance- Calibration and verification A novel approach has been established to address all of these factors. Developments are already in progress to prove the approach and that the low costs are achievable. This is called MicroSAR. This paper starts with an overview of the market status. A description of the MicroSAR system, its developments, calibration philosophy, trade-offs carried out, its performance envelope and an outline of the steps taken to achieve a low cost Synthetic Aperture Radar system are then presented.

Search and rescue response to a large-scale rockfall disaster.

PubMed

Procter, Emily; Strapazzon, Giacomo; Balkenhol, Karla; Fop, Ernst; Faggionato, Alessandro; Mayr, Karl; Falk, Markus; Brugger, Hermann

2015-03-01

To describe the prehospital management and safety of search and rescue (SAR) teams involved in a large-scale rockfall disaster and monitor the acute and chronic health effects on personnel with severe dolomitic dust exposure. SAR personnel underwent on-site medical screening and lung function testing 3 months and 3 years after the event. The emergency dispatch center was responsible for central coordination of resources. One hundred fifty SAR members from multidisciplinary air- and ground-based teams as well as geotechnical experts were dispatched to a provisionary operation center. Acute exposure to dolomite dust with detectable silicon and magnesium concentrations was not associated with (sub)acute or chronic sequelae or a clinically significant impairment in lung function in exposed personnel. The risk for personnel involved in mountain SAR operations is rarely reported and not easily investigated or quantified. This case exemplifies the importance of a multiskilled team and additional considerations for prehospital management during natural hazard events. Safety plans should include compulsory protective measures and medical monitoring of personnel. Copyright © 2015 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

GeoSAR: A Radar Terrain Mapping System for the New Millennium

NASA Technical Reports Server (NTRS)

Thompson, Thomas; vanZyl, Jakob; Hensley, Scott; Reis, James; Munjy, Riadh; Burton, John; Yoha, Robert

2000-01-01

GeoSAR Geographic Synthetic Aperture Radar) is a new 3 year effort to build a unique, dual-frequency, airborne Interferometric SAR for mapping of terrain. This is being pursued via a Consortium of the Jet Propulsion Laboratory (JPL), Calgis, Inc., and the California Department of Conservation. The airborne portion of this system will operate on a Calgis Gulfstream-II aircraft outfitted with P- and X-band Interferometric SARs. The ground portions of this system will be a suite of Flight Planning Software, an IFSAR Processor and a Radar-GIS Workstation. The airborne P-band and X-band radars will be constructed by JPL with the goal of obtaining foliage penetration at the longer P-band wavelengths. The P-band and X-band radar will operate at frequencies of 350 Mhz and 9.71 Ghz with bandwidths of either 80 or 160 Mhz. The airborne radars will be complemented with airborne laser system for measuring antenna positions. Aircraft flight lines and radar operating instructions will be computed with the Flight Planning Software The ground processing will be a two-step step process. First, the raw radar data will be processed into radar images and interferometer derived Digital Elevation Models (DEMs). Second, these radar images and DEMs will be processed with a Radar GIS Workstation which performs processes such as Projection Transformations, Registration, Geometric Adjustment, Mosaicking, Merging and Database Management. JPL will construct the IFSAR Processor and Calgis, Inc. will construct the Radar GIS Workstation. The GeoSAR Project was underway in November 1996 with a goal of having the radars and laser systems fully integrated onto the Calgis Gulfstream-II aircraft in early 1999. Then, Engineering Checkout and Calibration-Characterization Flights will be conducted through November 1999. The system will be completed at the end of 1999 and ready for routine operations in the year 2000.

Large Scale Assessment of Radio Frequency Interference Signatures in L-band SAR Data

NASA Astrophysics Data System (ADS)

Meyer, F. J.; Nicoll, J.

2011-12-01

Imagery of L-band Synthetic Aperture Radar (SAR) systems such as the PALSAR sensor on board the Advanced Land Observing Satellite (ALOS) has proven to be a valuable tool for observing environmental changes around the globe. Besides offering 24/7 operability, the L-band frequency provides improved interferometric coherence, and L-band polarimetric data has shown great potential for vegetation monitoring, sea ice classification, and the observation of glaciers and ice sheets. To maximize the benefit of missions such as ALOS PALSAR for environmental monitoring, data consistency and calibration are vital. Unfortunately, radio frequency interference (RFI) signatures from ground-based radar systems regularly impair L-band SAR data quality and consistency. With this study we present a large-scale analysis of typical RFI signatures that are regularly observed in L-band SAR data over the Americas. Through a study of the vast archive of L-band SAR data in the US Government Research Consortium (USGRC) data pool at the Alaska Satellite Facility (ASF) we were able to address the following research goals: 1. Assessment of RFI Signatures in L-band SAR data and their Effects on SAR Data Quality: An analysis of time-frequency properties of RFI signatures in L-band SAR data of the USGRC data pool is presented. It is shown that RFI-filtering algorithms implemented in the operational ALOS PALSAR processor are not sufficient to remove all RFI-related artifacts. In examples, the deleterious effects of RFI on SAR image quality, polarimetric signature, SAR phase, and interferometric coherence are presented. 2. Large-Scale Assessment of Severity, Spatial Distribution, and Temporal Variation of RFI Signatures in L-band SAR data: L-band SAR data in the USGRC data pool were screened for RFI using a custom algorithm. Per SAR frame, the algorithm creates geocoded frame bounding boxes that are color-coded according to RFI intensity and converted to KML files for analysis in Google Earth. From the screening results, parameters such as RFI severity and spatial distribution of RFI were derived. Through a comparison of RFI signatures in older SAR data from JAXA's Japanese Earth Resources Satellite (JERS-1) and recent ALOS PALSAR data, changes in RFI signatures in the Americas were derived, indicating a strong increase of L-band signal contamination over time. 3. An Optimized RFI Filter and its Performance in Data Restoration: An optimized RFI filter has been developed and tested at ASF. The algorithm has proven to be effective in detecting and removing RFI signatures in L-band SAR data and restoring the advertised quality of SAR imagery, polarization, and interferometric phase. The properties of the RFI filter will be described and its performance will be demonstrated in examples. The presented work is a prime example of large-scale research that is made possible by the availability of SAR data through the extensive data archive of the USGRC data pool at ASF.

The InSAR Scientific Computing Environment (ISCE): A Python Framework for Earth Science

NASA Astrophysics Data System (ADS)

Rosen, P. A.; Gurrola, E. M.; Agram, P. S.; Sacco, G. F.; Lavalle, M.

2015-12-01

The InSAR Scientific Computing Environment (ISCE, funded by NASA ESTO) provides a modern computing framework for geodetic image processing of InSAR data from a diverse array of radar satellites and aircraft. ISCE is both a modular, flexible, and extensible framework for building software components and applications as well as a toolbox of applications for processing raw or focused InSAR and Polarimetric InSAR data. The ISCE framework contains object-oriented Python components layered to construct Python InSAR components that manage legacy Fortran/C InSAR programs. Components are independently configurable in a layered manner to provide maximum control. Polymorphism is used to define a workflow in terms of abstract facilities for each processing step that are realized by specific components at run-time. This enables a single workflow to work on either raw or focused data from all sensors. ISCE can serve as the core of a production center to process Level-0 radar data to Level-3 products, but is amenable to interactive processing approaches that allow scientists to experiment with data to explore new ways of doing science with InSAR data. The NASA-ISRO SAR (NISAR) Mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystems. ISCE is planned as the foundational element in processing NISAR data, enabling a new class of analyses that take greater advantage of the long time and large spatial scales of these new data. NISAR will be but one mission in a constellation of radar satellites in the future delivering such data. ISCE currently supports all publicly available strip map mode space-borne SAR data since ERS and is expected to include support for upcoming missions. ISCE has been incorporated into two prototype cloud-based systems that have demonstrated its elasticity in addressing larger data processing problems in a "production" context and its ability to be controlled by individual science users on the cloud for large data problems. ISCE has been downloaded by over 200 users by a license for WinSAR members through the Unavco.org website. Others may apply directly to JPL for a license at download.jpl.nasa.gov.

Preliminary results of the comparative study between EO-1/Hyperion and ALOS/PALSAR

NASA Astrophysics Data System (ADS)

Koizumi, E.; Furuta, R.; Yamamoto, A.

2011-12-01

[Introduction]Hyper-spectral remote sensing images have been used for land-cover classification due to their high spectral resolutions. Synthetic Aperture Radar (SAR) remote sensing data are also useful to probe surface condition because radar image reflects surface geometry, although there are not so many reports about the land-cover detection with combination use of both hyper-spectral data and SAR data. Among SAR sensors, L-band SAR is thought to be useful tool to find physical properties because its comparatively long wave length can through small objects on surface. We are comparing the result of land cover classification and/or physical values from hyper-spectral and L-band SAR data to find the relationship between these two quite different sensors and to confirm the possibility of the combined analysis of hyper-spectral and L-band SAR data, and in this presentation we will report the preliminary result of this study. There are only few sources of both hyper-spectral and L-band SAR data from the space in this time, however, several space organizations plan to launch new satellites on which hyper-spectral or L-band SAR equipments are mounted in next few years. So, the importance of the combined analysis will increase more than ever. [Target Area]We are performing and planning analyses on the following areas in this study. (a)South of Cairo, Nile river area, Egypt, for sand, sandstone, limestone, river, crops. (b)Mount Sakurajima, Japan, for igneous rock and other related geological property. [Methods and Results]EO-1 Hyperion data are analyzed in this study as hyper-spectral data. The Hyperion equipment has 242 channels but some of them include full noise or have no data. We selected channels for analysis by checking each channel, and select about 150 channels (depend on the area). Before analysis, the atmospheric correction of ATCOR-3 was applied for the selected channels. The corrected data were analyzed by unsupervised classification or principal component analysis (PCA). We also did the unsupervised classification with the several components from PCA. According to the analysis results, several classifications can be extracted for each category (vegetation, sand and rocks, and water). One of the interesting results is that there are a few classes for sand as those of other categories, and these classes seem to reflect artificial and natural surface changes that are some result of excavation or scratching. ALOS PALSAR data are analyzed as L-band SAR data. We selected the Dual Polarization data for each target area. The data were converted to backscattered images, and then calculated some image statistic values. The topographic information also calculates with SAR interferometry technique as reference. Comparing the Hyperion classification results with the result of the calculation of statistic values from PALSAR, there are some areas where relativities seem to be confirmed. To confirm the combined analysis between hyper-spectral and L-band SAR data to detect and classify the surface material, further studies are still required. We will continue to investigate more efficient analytic methods and to examine other functions like the adopted channels, the number of class in classification, the kind of statistic information, and so on, to refine the method.

Integration of X-SAR observations with data of other remote sensing techniques: preliminary results achieved with Cosmo/SkyMed announcement of opportunity projects

NASA Astrophysics Data System (ADS)

Vespe, Francesco; Baldini, Luca; Notarnicola, Claudia; Prati, Claudio; Zerbini, Susanna; Celidonio, G.

2011-11-01

The Italian Space Agency is funding 27 scientific projects in the framework of Cosmo/Skymed program (hereafter CSK) . A subset of them are focusing on the improvements of the quality and quantity of information which can be extracted from X-SAR data if integrated with other independent techniques like GPS or SAR imagery in L and C bands. The GPS observations, namely zenith total delays estimated by means of GPS ground stations, could be helpful to estimate the troposphere bias to remove from IN-SAR imagery. Another contribution of GPS could be the improvements of the orbits of Cosmo/SkyMed satellites. In particular the GPS navigation data of the CSK satellites could serve to improve the atmospheric drag models acting on them. The integration of SAR data in L and C bands on the other hand are helpful to investigate land hydrogeology parameters as well as to improve global precipitation observations. The combined use of L, C and X SAR data with different penetration depth could give profiles of land surface properties, especially in forest and snow/ice-packs. For what concern the use of X-SAR imagery for rain precipitation monitoring, particular attention will be paid to its polarimetric properties that we plan to determine aligning the CSK observations with those obtained with ground L and C radars. Anyway the study goals, the approaches proposed, the test sites identified and the external data selected for the development and validation will be described for each project. Particular attention will be paid to single the advantages that the research activities can benefit from the added potentials of CSK system: the more frequent revisiting time and the higher resolution capabilities.

Improved Oceanographic Measurements from SAR Altimetry: Results and Scientific Roadmap from the ESA Cryosat Plus for Oceans Project

NASA Astrophysics Data System (ADS)

Benveniste, J.; Cotton, D.; Andersen, O. B.; Boy, F.; Cancet, M.; Dinardo, S.; Gommenginger, C.; Egido, A.; Fernandes, J.; Garcia, P. N.; Lucas, B.; Moreau, T.; Naeije, M.; Scharroo, R.; Stenseng, L.

2014-12-01

The ESA CryoSat mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar (SAR) mode. It thus provides the first opportunity to test and evaluate, using real data, the significant potential benefits of SAR altimetry for ocean applications. The objective of the CryoSat Plus for Oceans (CP4O) project is to develop and evaluate new ocean products from CryoSat data and so maximize the scientific return of CryoSat over oceans. The main focus of CP4O has been on the additional measurement capabilities that are offered by the SAR mode of the SIRAL altimeter, with further work in developing improved geophysical corrections. CP4O has developed SAR based ocean products for application in four themes: Open Oceans, Coastal Oceans, Polar Oceans and Sea Floor Topography. The team has developed a number of new processing schemes and compared and evaluated the resultant data products. This work has clearly demonstrated the improved ocean measuring capability offered by SAR mode altimetry and has also added significantly to our understanding of the issues around the processing and interpretation of SAR altimeter echoes. The project finishes in the summer of 2014, so this paper presents an overview of the major results and outlines a proposed roadmap for the further development and exploitation of these results in operational and scientific applications. The results are of course also highly relevant to support the planning for future missions, including Sentinel-3 and Jason-CS. The "CryoSat Plus for Oceans" (CP4O) project has been supported by ESA (Support To Science Element) and CNES.

Quarantine after an international biological weapons attack: medical and public health requirements for containment.

PubMed

Oren, Meir

2004-11-01

The world now faces the dreadful possibility of biological weapons attacks by terrorists. Healthcare systems would have to cope with such emergencies should all preemptive measures fail. Information gained from the Global Mercury exercise and the SARS outbreak has shown that containing an outbreak at the start is more effective than reacting to it once it has spread and that containment should be treated both nationally and internationally. On the national level this entails developing rapid and effective methods to detect and identify infected cases, and implementing isolation and control measures to lower the risk of further transmission of the disease while assuring the safety of medical teams and laboratory workers. Strategic contingency plans should incorporate well-defined procedures for hospitalization and isolation of patients, providing regional backup of medical personnel and equipment and maintaining close cooperation between the various bodies in the healthcare system. Quarantine is an effective containment measure, especially if voluntarily imposed. Modern communication systems can help by sending professional teams timely instructions and providing the public with information to reduce panic and stress during quarantine procedures. Informing the public poses a dilemma: finding a balance between giving advance warning of an imminent epidemic outbreak and ascertaining the likelihood of its occurrence. Containment of international bioterrorist attacks depends entirely on close international cooperation to implement national and international strategic contingency plans with free exchange of information and recognition of procedures.

Glaciological studies in the central Andes using AIRSAR/TOPSAR

NASA Technical Reports Server (NTRS)

Forster, Richard R.; Klein, Andrew G.; Blodgett, Troy A.; Isacks, Bryan L.

1993-01-01

The interaction of climate and topography in mountainous regions is dramatically expressed in the spatial distribution of glaciers and snowcover. Monitoring existing alpine glaciers and snow extent provides insight into the present mountain climate system and how it is changing, while mapping the positions of former glaciers as recorded in landforms such as cirques and moraines provide a record of the large past climate change associated with the last glacial maximum. The Andes are an ideal mountain range in which to study the response of snow and ice to past and present climate change. Their expansive latitudinal extent offers the opportunity to study glaciers in diverse climate settings from the tropical glaciers of Peru and Bolivia to the ice caps and tide-water glaciers of sub-polar Patagonia. SAR has advantages over traditional passive remote sensing instruments for monitoring present snow and ice and differentiating moraine relative ages. The cloud penetrating ability of SAR is indispensable for perennially cloud covered mountains. Snow and ice facies can be distinguished from SAR's response to surface roughness, liquid water content and grain size distribution. The combination of SAR with a coregestered high-resolution DEM (TOPSAR) provides a promising tool for measuring glacier change in three dimensions, thus allowing ice volume change to be measured directly. The change in moraine surface roughness over time enables SAR to differentiate older from younger moraines. Polarimetric SAR data have been used to distinguish snow and ice facies and relatively date moraines. However, both algorithms are still experimental and require ground truth verification. We plan to extend the SAR classification of snow and ice facies and moraine age beyond the ground truth sites to throughout the Cordillera Real to provide a regional view of past and present snow and ice. The high resolution DEM will enhance the SAR moraine dating technique by discriminating relative ages based on moraine slope degradation.

Full-spectrum disease response : beyond just the flu.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Knazovich, Michael Ward; Cox, Warren B.; Henderson, Samuel Arthur

Why plan beyond the flu: (1) the installation may be the target of bioterrorism - National Laboratory, military base collocated in large population center; and (2) International Airport - transport of infectious agents to the area - Sandia is a global enterprise and staff visit many foreign countries. In addition to the Pandemic Plan, Sandia has developed a separate Disease Response Plan (DRP). The DRP addresses Category A, B pathogens and Severe Acute Respiratory Syndrome (SARS). The DRP contains the Cities Readiness Initiative sub-plan for disbursement of Strategic National Stockpile assets.

Advanced Unsupervised Classification Methods to Detect Anomalies on Earthen Levees Using Polarimetric SAR Imagery

PubMed Central

Marapareddy, Ramakalavathi; Aanstoos, James V.; Younan, Nicolas H.

2016-01-01

Fully polarimetric Synthetic Aperture Radar (polSAR) data analysis has wide applications for terrain and ground cover classification. The dynamics of surface and subsurface water events can lead to slope instability resulting in slough slides on earthen levees. Early detection of these anomalies by a remote sensing approach could save time versus direct assessment. We used L-band Synthetic Aperture Radar (SAR) to screen levees for anomalies. SAR technology, due to its high spatial resolution and soil penetration capability, is a good choice for identifying problematic areas on earthen levees. Using the parameters entropy (H), anisotropy (A), alpha (α), and eigenvalues (λ, λ1, λ2, and λ3), we implemented several unsupervised classification algorithms for the identification of anomalies on the levee. The classification techniques applied are H/α, H/A, A/α, Wishart H/α, Wishart H/A/α, and H/α/λ classification algorithms. In this work, the effectiveness of the algorithms was demonstrated using quad-polarimetric L-band SAR imagery from the NASA Jet Propulsion Laboratory’s (JPL’s) Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR). The study area is a section of the lower Mississippi River valley in the Southern USA, where earthen flood control levees are maintained by the US Army Corps of Engineers. PMID:27322270

Infection control for SARS in a tertiary neonatal centre.

PubMed

Ng, P C; So, K W; Leung, T F; Cheng, F W T; Lyon, D J; Wong, W; Cheung, K L; Fung, K S C; Lee, C H; Li, A M; Hon, K L E; Li, C K; Fok, T F

2003-09-01

The Severe Acute Respiratory Syndrome (SARS) is a newly discovered infectious disease caused by a novel coronavirus, which can readily spread in the healthcare setting. A recent community outbreak in Hong Kong infected a significant number of pregnant women who subsequently required emergency caesarean section for deteriorating maternal condition and respiratory failure. As no neonatal clinician has any experience in looking after these high risk infants, stringent infection control measures for prevention of cross infection between patients and staff are important to safeguard the wellbeing of the work force and to avoid nosocomial spread of SARS within the neonatal unit. This article describes the infection control and patient triage policy of the neonatal unit at the Prince of Wales Hospital, Hong Kong. We hope this information is useful in helping other units to formulate their own infection control plans according to their own unit configuration and clinical needs.

Reflection on SARS precautions in a severe intellectual disabilities hospital in Hong Kong.

PubMed

Wong, S Y; Lim, W W C; Que, T L; Au, D M Y

2005-05-01

Hong Kong went through a battle with a new respiratory disease, severe acute respiratory syndrome (SARS), from March to June 2003. All clinical settings, including rehabilitative and infirmary setting, have actively involved in fighting against the infection. The intent of this paper was to reflect on the SARS precautionary measures that had been taken in a severe intellectual disabilities hospital in Hong Kong. A review on six SARS precautionary measures were conducted. They were assessment of risk, formulation of operational guidelines, implementation of infection control measures, education and training of staff, conducting audits and carrying out environmental improvement work. Patients were at risk of getting infected from carers, visitors, volunteers, and staff and patients of general hospitals. A SARS Quarantine Unit, isolation ward, was opened to isolate patients who might have had close contact with SARS patients during a stay in a general hospital or when they returned from home leave. Undoubtedly, both staff and relatives participated in preventing the patients from being infected. No day leave and home leave was reported and the number of hospitalization in general hospital was decreased during the critical period. Three infection control audits were conducted and improvement work was carried out subsequently. The practice of grouping within a standard isolation room is recommended to continue in the future. Moreover, intensive infection control training for all staff is of highest importance to safeguard the health of both staff and patient.

Implementing the HDF-EOS5 software library for data products in the UNAVCO InSAR archive

NASA Astrophysics Data System (ADS)

Baker, Scott; Meertens, Charles; Crosby, Christopher

2017-04-01

UNAVCO is a non-profit university-governed consortium that operates the U.S. National Science Foundation (NSF) Geodesy Advancing Geosciences and EarthScope (GAGE) facility and provides operational support to the Western North America InSAR Consortium (WInSAR). The seamless synthetic aperture radar archive (SSARA) is a seamless distributed access system for SAR data and higher-level data products. Under the NASA-funded SSARA project, a user-contributed InSAR archive for interferograms, time series, and other derived data products was developed at UNAVCO. The InSAR archive development has led to the adoption of the HDF-EOS5 data model, file format, and library. The HDF-EOS software library was designed to support NASA Earth Observation System (EOS) science data products and provides data structures for radar geometry (Swath) and geocoded (Grid) data based on the HDF5 data model and file format provided by the HDF Group. HDF-EOS5 inherits the benefits of HDF5 (open-source software support, internal compression, portability, support for structural data, self-describing file metadata enhanced performance, and xml support) and provides a way to standardize InSAR data products. Instrument- and datatype-independent services, such as subsetting, can be applied to files across a wide variety of data products through the same library interface. The library allows integration with GIS software packages such as ArcGIS and GDAL, conversion to other data formats like NetCDF and GeoTIFF, and is extensible with new data structures to support future requirements. UNAVCO maintains a GitHub repository that provides example software for creating data products from popular InSAR processing software packages like GMT5SAR and ISCE as well as examples for reading and converting the data products into other formats. Digital object identifiers (DOI) have been incorporated into the InSAR archive allowing users to assign a permanent location for their processed result and easily reference the final data products. A metadata attribute is added to the HDF-EOS5 file when a DOI is minted for a data product. These data products are searchable through the SSARA federated query providing access to processed data for both expert and non-expert InSAR users. The archive facilitates timely distribution of processed data with particular importance for geohazards and event response.

Mapping Changes and Damages in Areas of Conflict: From Archive C-Band SAR Data to New HR X-Band Imagery, Towards the Sentinels

NASA Astrophysics Data System (ADS)

Tapete, Deodato; Cigna, Francesca; Donoghue, Daniel N. M.; Philip, Graham

2015-05-01

On the turn of radar space science with the recent launch of Sentinel-1A, we investigate how to better exploit the opportunities offered by large C-band SAR archives and increasing datasets of HR to VHR X-band data, to map changes and damages in urban and rural areas affected by conflicts. We implement a dual approach coupling multi-interferogram processing and amplitude change detection, to assess the impact of the recent civil war on the city of Homs, Western Syria, and the surrounding semi-arid landscape. More than 280,000 coherent pixels are retrieved from Small BAseline Subset (SBAS) processing of the 8year-long ENVISAT ASAR IS2 archive, to quantify land subsidence due to pre-war water abstraction in rural areas. Damages in Homs are detected by analysing the changes of SAR backscattering (σ0), comparing 3m-resolution StripMap TerraSAR-X pairs from 2009 to 2014. Pre-war alteration is differentiated from war-related damages via operator-driven interpretation of the σ0 patterns.

Multi-linear sparse reconstruction for SAR imaging based on higher-order SVD

NASA Astrophysics Data System (ADS)

Gao, Yu-Fei; Gui, Guan; Cong, Xun-Chao; Yang, Yue; Zou, Yan-Bin; Wan, Qun

2017-12-01

This paper focuses on the spotlight synthetic aperture radar (SAR) imaging for point scattering targets based on tensor modeling. In a real-world scenario, scatterers usually distribute in the block sparse pattern. Such a distribution feature has been scarcely utilized by the previous studies of SAR imaging. Our work takes advantage of this structure property of the target scene, constructing a multi-linear sparse reconstruction algorithm for SAR imaging. The multi-linear block sparsity is introduced into higher-order singular value decomposition (SVD) with a dictionary constructing procedure by this research. The simulation experiments for ideal point targets show the robustness of the proposed algorithm to the noise and sidelobe disturbance which always influence the imaging quality of the conventional methods. The computational resources requirement is further investigated in this paper. As a consequence of the algorithm complexity analysis, the present method possesses the superiority on resource consumption compared with the classic matching pursuit method. The imaging implementations for practical measured data also demonstrate the effectiveness of the algorithm developed in this paper.

Combining the benefits of decision science and financial analysis in public health management: a county-specific budgeting and planning model.

PubMed

Fos, Peter J; Miller, Danny L; Amy, Brian W; Zuniga, Miguel A

2004-01-01

State public health agencies are charged with providing and overseeing the management of basic public health services on a population-wide basis. These activities have a re-emphasized focus as a result of the events of September 11, 2001, the subsequent anthrax events, and the continuing importance placed on bioterrorism preparedness, West Nile virus, and emerging infectious diseases (eg, monkeypox, SARS). This has added to the tension that exists in budgeting and planning, given the diverse constituencies that are served in each state. State health agencies must be prepared to allocate finite resources in a more formal manner to be able to provide basic public health services on a routine basis, as well as during outbreaks. This article describes the use of an analytical approach to assist financial analysis that is used for budgeting and planning in a state health agency. The combined benefits of decision science and financial analysis are needed to adequately and appropriately plan and budget to meet the diverse needs of the populations within a state. Health and financial indicators are incorporated into a decision model, based on multicriteria decision theory, that has been employed to acquire information about counties and public health programs areas within a county, that reflect the impact of planning and budgeting efforts. This information can be used to allocate resources, to distribute funds for health care services, and to guide public health finance policy formulation and implementation.

Unsupervised Wishart Classfication of Wetlands in Newfoundland, Canada Using Polsar Data Based on Fisher Linear Discriminant Analysis

NASA Astrophysics Data System (ADS)

Mohammadimanesh, F.; Salehi, B.; Mahdianpari, M.; Homayouni, S.

2016-06-01

Polarimetric Synthetic Aperture Radar (PolSAR) imagery is a complex multi-dimensional dataset, which is an important source of information for various natural resources and environmental classification and monitoring applications. PolSAR imagery produces valuable information by observing scattering mechanisms from different natural and man-made objects. Land cover mapping using PolSAR data classification is one of the most important applications of SAR remote sensing earth observations, which have gained increasing attention in the recent years. However, one of the most challenging aspects of classification is selecting features with maximum discrimination capability. To address this challenge, a statistical approach based on the Fisher Linear Discriminant Analysis (FLDA) and the incorporation of physical interpretation of PolSAR data into classification is proposed in this paper. After pre-processing of PolSAR data, including the speckle reduction, the H/α classification is used in order to classify the basic scattering mechanisms. Then, a new method for feature weighting, based on the fusion of FLDA and physical interpretation, is implemented. This method proves to increase the classification accuracy as well as increasing between-class discrimination in the final Wishart classification. The proposed method was applied to a full polarimetric C-band RADARSAT-2 data set from Avalon area, Newfoundland and Labrador, Canada. This imagery has been acquired in June 2015, and covers various types of wetlands including bogs, fens, marshes and shallow water. The results were compared with the standard Wishart classification, and an improvement of about 20% was achieved in the overall accuracy. This method provides an opportunity for operational wetland classification in northern latitude with high accuracy using only SAR polarimetric data.

Land subsidence in southwest Cyprus revealed from C-band radar interferometry

NASA Astrophysics Data System (ADS)

Michalis, Pantelis; Giourou, Anthi; Charalampopoulou, Betty; Li, Zhenhong; Li, Yongsheng

2014-08-01

Land subsidence is a major worldwide hazard, and causes many problems including: damage to public facilities such as bridges, roads, railways, electric power lines, underground pipes; damage to private and public buildings; and in some cases of low-lying land, can increase the risk of coastal flooding from storm surges and rising sea-levels. The island of Cyprus is famous for its complex geology, particularly in the southwest part of the island. Deposits of massive breccias (melange) are widely exposed in the Paphos District situated between the Troodos Mountains and the sea. These deposits are rich in clay minerals that are prone to landslide phenomena. With its global coverage and all-weather imaging capability, Interferometric SAR (InSAR) is revolutionizing our ability to image the Earth's surface and the evolution of its shape over time. In this paper, an advanced InSAR time series technique, InSAR TS + AEM, has been employed to analysed C-band ERS and Envisat data collected over southwest Cyprus during the period from 1992 to 2010. Our InSAR time series results suggest that: (1) a total number of 274,619 coherent pixels with a density of 46 points per squared km were detected in the area of interest; and (2) clear surface displacements can be observed in several areas. The combination of archived ESA SAR datasets allows a long record (~18 years) of historic deformation to be measured over a large region. Ultimately this should help inform land managers in assessing land subsidence and planning appropriate remedial measures.

Global Tropospheric Noise Maps for InSAR Observations

NASA Astrophysics Data System (ADS)

Yun, S. H.; Hensley, S.; Agram, P. S.; Chaubell, M.; Fielding, E. J.; Pan, L.

2014-12-01

Radio wave's differential phase delay variation through the troposphere is the largest error sources in Interferometric Synthetic Aperture Radar (InSAR) measurements, and water vapor variability in the troposphere is known to be the dominant factor. We use the precipitable water vapor (PWV) products from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensors mounted on Terra and Aqua satellites to produce tropospheric noise maps of InSAR. We estimate the slope and y-intercept of power spectral density curve of MODIS PWV and calculate the structure function to estimate the expected tropospheric noise level as a function of distance. The results serve two purposes: 1) to provide guidance on the expected covariance matrix for geophysical modeling, 2) to provide quantitative basis for the science Level-1 requirements of the planned NASA-ISRO L-band SAR mission (NISAR mission). We populate lookup tables of such power spectrum parameters derived from each 1-by-1 degree tile of global coverage. The MODIS data were retrieved from OSCAR (Online Services for Correcting Atmosphere in Radar) server. Users will be able to use the lookup tables and calculate expected tropospheric noise level of any date of MODIS data at any distance scale. Such calculation results can be used for constructing covariance matrix for geophysical modeling, or building statistics to support InSAR missions' requirements. For example, about 74% of the world had InSAR tropospheric noise level (along a radar line-of-sight for an incidence angle of 40 degrees) of 2 cm or less at 50 km distance scale during the time period of 2010/01/01 - 2010/01/09.

Comparative Study of Speckle Filtering Methods in PolSAR Radar Images

NASA Astrophysics Data System (ADS)

Boutarfa, S.; Bouchemakh, L.; Smara, Y.

2015-04-01

Images acquired by polarimetric SAR (PolSAR) radar systems are characterized by the presence of a noise called speckle. This noise has a multiplicative nature, corrupts both the amplitude and phase images, which complicates data interpretation, degrades segmentation performance and reduces the detectability of targets. Hence, the need to preprocess the images by adapted filtering methods before analysis.In this paper, we present a comparative study of implemented methods for reducing speckle in PolSAR images. These developed filters are: refined Lee filter based on the estimation of the minimum mean square error MMSE, improved Sigma filter with detection of strong scatterers based on the calculation of the coherency matrix to detect the different scatterers in order to preserve the polarization signature and maintain structures that are necessary for image interpretation, filtering by stationary wavelet transform SWT using multi-scale edge detection and the technique for improving the wavelet coefficients called SSC (sum of squared coefficients), and Turbo filter which is a combination between two complementary filters the refined Lee filter and the wavelet transform SWT. One filter can boost up the results of the other.The originality of our work is based on the application of these methods to several types of images: amplitude, intensity and complex, from a satellite or an airborne radar, and on the optimization of wavelet filtering by adding a parameter in the calculation of the threshold. This parameter will control the filtering effect and get a good compromise between smoothing homogeneous areas and preserving linear structures.The methods are applied to the fully polarimetric RADARSAT-2 images (HH, HV, VH, VV) acquired on Algiers, Algeria, in C-band and to the three polarimetric E-SAR images (HH, HV, VV) acquired on Oberpfaffenhofen area located in Munich, Germany, in P-band.To evaluate the performance of each filter, we used the following criteria: smoothing homogeneous areas, preserving edges and polarimetric information.Experimental results are included to illustrate the different implemented methods.

SAR interferometry monitoring along the ancient Rome City Walls -the PROTHEGO project case study

NASA Astrophysics Data System (ADS)

Carta, Cristina; Cimino, Maria gabriella; Leoni, Gabriele; Marcelli, Marina; Margottini, Claudio; Spizzichino, Daniele

2017-04-01

Led by the Italian Institute for Environmental Protection and Research, in collaboration with NERC British Geological Survey, Geological and Mining Institute of Spain, University of Milano-Bicocca and Cyprus University of Technology, the PROTHEGO project, co-funded in the framework of JPI on Cultural Heritage EU program (2015-2018), brings an innovative contribution towards the analysis of geo-hazards in areas of cultural heritage in Europe. The project apply InSAR techniques to monitor monuments and sites that are potentially unstable due to natural geo-hazard. After the remote sensing investigation, detailed geological interpretation, hazard analysis, local-scale monitoring, advanced modeling and field surveying for some case studies is implemented. The selected case studies are: the Alhambra in Granada (ES); the Choirokoitia village (CY); the Derwent Valley Mills (UK); the Pompei archaeological site and Historical centre of Rome (IT). In this work, in particular, we will focus on ground deformation measurements (obtained by satellite SAR Interferometry) and on their interpretation with respect to the ancient Rome City Walls. The research activities carried out jointly with the Superintendence's technicians, foresee the implementation of a dedicated web GIS platform as a final repository for data storage and spatial data elaboration. The entire circuit of the ancient city walls (both Mura Aureliane and Mura Gianicolensi), was digitalized and georeferenced. All the elements (towers, gates and wall segments) were drawn and collected in order to produce a map of elements at risk. A detailed historical analysis (during the last twenty years) of the ground and structural deformations were performed. A specific data sheet of ruptures was created and fulfilled in order to produce a geographic inventory of past damage. This data sheet contains the following attributes: triggering data; typology of damage; dimension, triggering mechanism; presence of restoration works. More than thirty events were collected. The most frequent damages refers to human impacts, detachment of brick outer surface and wall collapse. The resulting damage layer was compared with different local hazard maps (e.g. landslide; subsidence; seismic) and also with the PS (monitored point) coming from the satellite analysis. The satellite monitoring data and analysis was based on the processing of COSMO-SkyMed image data (from 2011 to 2014). The data were obtained from the Extraordinary Monitoring Project Plan, implemented by the Italian Environmental Ministry. The preliminary analysis did not show large areas affected by deformations. A wide area affected by subsidence phenomena was detected in the south portion of the walls (close to the Ostiense district). While smaller and localized detachments were detected in the northern sector. Starting from these firsts results, COSMO-SkyMed SAR interferometry analysis seems to be very efficient due to its capability of providing a large number of deformation measurements over the whole site and structures with relatively small cost and without any impact. Cross analysis between interferometric results, natural hazard and historical data of the site (e.g. collapses, works) is still in progress in order to define a forecasting model aiming at an early identification of areas subjected to potential instability or sudden collapse

Land subsidence in the Yangtze River Delta, China revealed from multi-frequency SAR Interferometry

NASA Astrophysics Data System (ADS)

Li, Zhenhong; Motagh, Mahdi; Yu, Jun; Gong, Xulong; Wu, Jianqiang; Zhu, Yefei; Chen, Huogen; Zhang, Dengming; Xu, Yulin

2014-05-01

Land subsidence is a major worldwide hazard, and its principal causes are subsurface fluid withdrawal, drainage of organic soils, sinkholes, underground mining, hydrocompaction, thawing permafrost, and natural consolidation. Land subsidence causes many problems including: damage to public facilities such as bridges, roads, railroads, electric power lines, underground pipes; damage to private and public buildings; and in some cases of low-lying land, can increase the risk of coastal flooding from storm surges and rising sea-levels. In China, approximately 48600 km2 of land, an area roughly 30 times of the size of the Greater London, has subsided (nearly 50 cities across 16 provinces), and the annual direct economic loss is estimated to be more than RMB 100 million (~12 million). It is believed that the Suzhou-Wuxi-Changzhou region within the Yangtze River Delta is the most severely affected area for subsidence hazards in China. With its global coverage and all-weather imaging capability, Interferometric SAR (InSAR) is revolutionizing our ability to image the Earth's surface and the evolution of its shape over time. In this paper, an advanced InSAR time series technique, InSAR TS + AEM, has been employed to analysed ERS (C-band), Envisat (C-band) and TerraSAR-X (X-band) data collected over the Suzhou-Wuxi-Changzhou region during the period from 1992 to 2013. Validation with precise levelling and GPS data suggest: (1) the accuracy of the InSAR-derived mean velocity measurements is 1-3 mm/yr; (2) InSAR-derived displacements agreed with precise levelling with root mean square errors around 5 mm. It is evident that InSAR TS + AEM can be used to image the evolution of deformation patterns in the Suzhou-Wuxi-Changzhou region over time: the maximum mean velocity decreased from ~12 cm/yr during the period of 1992-1993 to ~2 cm/yr in 2003-2013. This is believed to be a result of the prohibition of groundwater use carried out by Jiangsu provincial government. The combination of multi-frequency SAR datasets allows a long record (~20 years) of historic deformation to be measured over a large region. Ultimately this should help inform land managers in assessing land subsidence and planning appropriate remedial measures.

Monitoring of urban subsidence with SAR interferometric point target analysis: A case study in Suzhou, China

NASA Astrophysics Data System (ADS)

Zhang, Yonghong; Zhang, Jixian; Wu, Hongan; Lu, Zhong; Guangtong, Sun

2011-10-01

Ground subsidence, mainly caused by over exploitation of groundwater and other underground resources, such as oil, gas and coal, occurs in many cities in China. The annual direct loss associated with subsidence across the country is estimated to exceed 100 million US dollar. Interferometric SAR (InSAR) is a powerful tool to map ground deformation at an unprecedented level of spatial detail. It has been widely used to investigate the deformation resulting from earthquakes, volcanoes and subsidence. Repeat-pass InSAR, however, may fail due to impacts of spatial decorrelation, temporal decorrelation and heterogeneous refractivity of atmosphere. In urban areas, a large amount of natural stable radar reflectors exists, such as buildings and engineering structures, at which radar signals can remain coherent during a long time interval. Interferometric point target analysis (IPTA) technique, also known as persistent scatterers (PS) InSAR is based on these reflectors. It overcomes the shortfalls in conventional InSAR. This paper presents a procedure for urban subsidence monitoring with IPTA. Calculation of linear deformation rate and height residual, and the non-linear deformation estimate, respectively, are discussed in detail. Especially, the former is highlighted by a novel and easily implemented 2-dimensional spatial search algorithm. Practically useful solutions that can significantly improve the robustness of IPTA, are recommended. Finally, the proposed procedure is applied to mapping the ground subsidence in Suzhou city, Jiangsu province, China. Thirty-four ERS-1/2 SAR scenes are analyzed, and the deformation information over 38,881 point targets between 1992 and 2000 are generated. The IPTA-derived deformation estimates correspond well with leveling measurements, demonstrating the potential of the proposed subsidence monitoring procedure based on IPTA technique. Two shortcomings of the IPTA-based procedure, e.g., the requirement of large number of SAR images and assumed linear plus non-linear deformation model, are discussed as the topics of further research.

Observation of sea-ice dynamics using synthetic aperture radar images: Automated analysis

NASA Technical Reports Server (NTRS)

Vesecky, John F.; Samadani, Ramin; Smith, Martha P.; Daida, Jason M.; Bracewell, Ronald N.

1988-01-01

The European Space Agency's ERS-1 satellite, as well as others planned to follow, is expected to carry synthetic-aperture radars (SARs) over the polar regions beginning in 1989. A key component in utilization of these SAR data is an automated scheme for extracting the sea-ice velocity field from a time sequence of SAR images of the same geographical region. Two techniques for automated sea-ice tracking, image pyramid area correlation (hierarchical correlation) and feature tracking, are described. Each technique is applied to a pair of Seasat SAR sea-ice images. The results compare well with each other and with manually tracked estimates of the ice velocity. The advantages and disadvantages of these automated methods are pointed out. Using these ice velocity field estimates it is possible to construct one sea-ice image from the other member of the pair. Comparing the reconstructed image with the observed image, errors in the estimated velocity field can be recognized and a useful probable error display created automatically to accompany ice velocity estimates. It is suggested that this error display may be useful in segmenting the sea ice observed into regions that move as rigid plates of significant ice velocity shear and distortion.

Theoretical analysis, design and development of a 27-MHz folded loop antenna as a potential applicator in hyperthermia treatment.

PubMed

Kouloulias, Vassilis; Karanasiou, Irene; Giamalaki, Melina; Matsopoulos, George; Kouvaris, John; Kelekis, Nikolaos; Uzunoglu, Nikolaos

2015-02-01

A hyperthermia system using a folded loop antenna applicator at 27 MHz for soft tissue treatment was investigated both theoretically and experimentally to evaluate its clinical value. The electromagnetic analysis of a 27-MHz folded loop antenna for use in human tissue was based on a customised software tool and led to the design and development of the proposed hyperthermia system. The system was experimentally validated using specific absorption rate (SAR) distribution estimations through temperature distribution measurements of a muscle tissue phantom after electromagnetic exposure. Various scenarios for optimal antenna positioning were also performed. Comparison of the theoretical and experimental analysis results shows satisfactory agreement. The SAR level of 50% reaches 8 cm depth in the tissue phantom. Thus, based on the maximum observed SAR values that were of the order of 100 W/kg, the antenna specified is suitable for deep tumour heating. Theoretical and experimental SAR distribution results as derived from this study are in agreement. The proposed folded loop antenna seems appropriate for use in hyperthermia treatment, achieving proper planning and local treatment of deeply seated affected areas and lesions.

Tropical Wetland Monitoring Using RapidEye and Sentinel 1 Satellite Images in Ifakara (Tanzania)

NASA Astrophysics Data System (ADS)

Kirimi, Fridah; Menz, Gunter

2016-08-01

Food insecurity has been a topic of concern particularly for the developing countries. Wetlands have a consistent supply of water throughout the year. To determine whether the utilization of the wetland for increased food production is viable, there was need to analyse the land uses in different months of the year to better understand the dynamics of existing vegetation.Support Vector Machine was used to classify the optical to establish the dynamics of changing vegetation. Bare land coverage gives an indication of the potentially available land that can be utilized for crop growth. The optical images are affected by cloud coverage. As a remedial action the use of SAR images in monitoring the wetlands is assessed. A great percentage of land remains bare. Quantification of this from the classified images forms a basis upon which decisions on strategic plans of increasing production sustainably in the region can be implemented.

SPICE: Sentinel-3 Performance Improvement for Ice Sheets

NASA Astrophysics Data System (ADS)

McMillan, M.; Escola, R.; Roca, M.; Thibaut, P.; Aublanc, J.; Shepherd, A.; Remy, F.; Benveniste, J.; Ambrózio, A.; Restano, M.

2017-12-01

For the past 25 years, polar-orbiting satellite radar altimeters have provided a valuable record of ice sheet elevation change and mass balance. One of the principle challenges associated with radar altimetry comes from the relatively large ground footprint of conventional pulse-limited radars, which reduces their capacity to make measurements in areas of complex topographic terrain. In recent years, progress has been made towards improving ground resolution, through the implementation of Synthetic Aperture Radar (SAR), or Delay-Doppler, techniques. In 2010, the launch of CryoSat-2 heralded the start of a new era of SAR Interferometric (SARIn) altimetry. However, because the satellite operated in SARIn and LRM mode over the ice sheets, many of the non-interferometric SAR altimeter processing techniques have been optimized for water and sea ice surfaces only. The launch of Sentinel-3, which provides full non-interferometric SAR coverage of the ice sheets, therefore presents the opportunity to further develop these SAR processing methodologies over ice sheets. Here we present results from SPICE, a 2 year study that focuses on (1) developing and evaluating Sentinel-3 SAR altimetry processing methodologies over the Polar ice sheets, and (2) investigating radar wave penetration through comparisons of Ku- and Ka-band satellite measurements. The project, which is funded by ESA's SEOM (Scientific Exploitation of Operational Missions) programme, has worked in advance of the operational phase of Sentinel-3, to emulate Sentinel-3 SAR and pseudo-LRM data from dedicated CryoSat-2 SAR acquisitions made at the Lake Vostok, Dome C and Spirit sites in East Antarctica, and from reprocessed SARIn data in Greenland. In Phase 1 of the project we have evaluated existing processing methodologies, and in Phase 2 we are investigating new evolutions to the Delay-Doppler Processing (DDP) and retracking chains. In this presentation we (1) evaluate the existing Sentinel-3 processing chain by comparing our emulated Sentinel-3 elevations to reference airborne datasets, (2) describe new developments to the DDP and retracking algorithms that are aimed at improving the certainty of retrievals over ice sheets, and (3) investigate radar wave penetration by comparing our SAR data to waveforms and elevations acquired by AltiKa at Ka-band.

The Biomass mission: a step forward in quantifying forest biomass and structure

NASA Astrophysics Data System (ADS)

LE Toan, T.

2015-12-01

The primary aim of the ESA BIOMASS mission is to determine, for the first time and in a consistent manner, the global distribution of above-ground forest biomass (AGB) in order to provide greatly improved quantification of the size and distribution of the terrestrial carbon pool, and improved estimates of terrestrial carbon fluxes. Specifically, BIOMASS will measure forest carbon stock, as well as forest height, from data provided by a single satellite giving a biomass map covering tropical, temperate and boreal forests at a resolution of around 200 m every 6 months throughout the five years of the mission. BIOMASS will use a long wavelength SAR (P-band) providing three mutually supporting measurement techniques, namely polarimetric SAR (PolSAR), polarimetric interferometric SAR (PolInSAR) and tomographic SAR (TomoSAR). The combination of these techniques will significantly reduce the uncertainties in biomass retrievals by yielding complementary information on biomass properties. Horizontal mapping: For a forest canopy, the P-band radar waves penetrate deep into the canopy, and their interaction with the structure of the forest will be exploited to map above ground biomass (AGB), as demonstrated from airborne data for temperate, boreal forests and tropical forest. Height mapping: By repeat revisits to the same location, the PolInSAR measurements will be used to estimate the height of scattering in the forest canopy. The long wavelength used by BIOMASS is crucial for the temporal coherence to be preserved over much longer timescales than at L-band, for example. 3D mapping: The P-band frequency used by BIOMASS is low enough to ensure penetration through the entire canopy, even in dense tropical forests. As a consequence, resolution of the vertical structure of the forest will be possible using tomographic methods from the multi-baseline acquisitions. This is the concept of SAR tomography, which will be implemented in the BIOMASS mission. The improvement in the quantification of the vegetation structure, will have an important impact in many aspects of ecosystem function, such as carbon cycling and biodiversity. For example, areas of forest loss or degradation and areas of growth or recovery, can be determined by the vegetation structure and its temporal change.

Emergency product generation for disaster management using RISAT and DMSAR quick look SAR processors

NASA Astrophysics Data System (ADS)

Desai, Nilesh; Sharma, Ritesh; Kumar, Saravana; Misra, Tapan; Gujraty, Virendra; Rana, SurinderSingh

2006-12-01

Since last few years, ISRO has embarked upon the development of two complex Synthetic Aperture Radar (SAR) missions, viz. Spaceborne Radar Imaging Satellite (RISAT) and Airborne SAR for Disaster Mangement (DMSAR), as a capacity building measure under country's Disaster Management Support (DMS) Program, for estimating the extent of damage over large areas (~75 Km) and also assess the effectiveness of the relief measures undertaken during natural disasters such as cyclones, epidemics, earthquakes, floods and landslides, forest fires, crop diseases etc. Synthetic Aperture Radar (SAR) has an unique role to play in mapping and monitoring of large areas affected by natural disasters especially floods, owing to its unique capability to see through clouds as well as all-weather imaging capability. The generation of SAR images with quick turn around time is very essential to meet the above DMS objectives. Thus the development of SAR Processors, for these two SAR systems poses considerable challenges and design efforts. Considering the growing user demand and inevitable necessity for a full-fledged high throughput processor, to process SAR data and generate image in real or near-real time, the design and development of a generic SAR Processor has been taken up and evolved, which will meet the SAR processing requirements for both Airborne and Spaceborne SAR systems. This hardware SAR processor is being built, to the extent possible, using only Commercial-Off-The-Shelf (COTS) DSP and other hardware plug-in modules on a Compact PCI (cPCI) platform. Thus, the major thrust has been on working out Multi-processor Digital Signal Processor (DSP) architecture and algorithm development and optimization rather than hardware design and fabrication. For DMSAR, this generic SAR Processor operates as a Quick Look SAR Processor (QLP) on-board the aircraft to produce real time full swath DMSAR images and as a ground based Near-Real Time high precision full swath Processor (NRTP). It will generate full-swath (6 to 75 Kms) DMSAR images in 1m / 3m / 5m / 10m / 30m resolution SAR operating modes. For RISAT mission, this generic Quick Look SAR Processor will be mainly used for browse product generation at NRSA-Shadnagar (SAN) ground receive station. RISAT QLP/NRTP is also proposed to provide an alternative emergency SAR product generation chain. For this, the S/C aux data appended in Onboard SAR Frame Format (x, y, z, x', y', z', roll, pitch, yaw) and predicted orbit from previous days Orbit Determination data will be used. The QLP / NRTP will produce ground range images in real / near real time. For emergency data product generation, additional Off-line tasks like geo-tagging, masking, QC etc needs to be performed on the processed image. The QLP / NRTP would generate geo-tagged images from the annotation data available from the SAR P/L data itself. Since the orbit & attitude information are taken as it is, the location accuracy will be poorer compared to the product generated using ADIF, where smoothened attitude and orbit are made available. Additional tasks like masking, output formatting and Quality checking of the data product will be carried out at Balanagar, NRSA after the image annotated data from QLP / NRTP is sent to Balanagar. The necessary interfaces to the QLP/NRTP for Emergency product generation are also being worked out. As is widely acknowledged, QLP/NRTP for RISAT and DMSAR is an ambitious effort and the technology of future. It is expected that by the middle of next decade, the next generation SAR missions worldwide will have onboard SAR Processors of varying capabilities and generate SAR Data products and Information products onboard instead of SAR raw data. Thus, it is also envisaged that these activities related to QLP/NRTP implementation for RISAT ground segment and DMSAR will be a significant step which will directly feed into the development of onboard real time processing systems for ISRO's future space borne SAR missions. This paper describes the design requirements, configuration details and salient features, apart from highlighting the utility of these Quick Look SAR processors for RISAT and DMSAR, for generation of emergency products for Disaster management.

Adapted RF pulse design for SAR reduction in parallel excitation with experimental verification at 9.4 T.

PubMed

Wu, Xiaoping; Akgün, Can; Vaughan, J Thomas; Andersen, Peter; Strupp, John; Uğurbil, Kâmil; Van de Moortele, Pierre-François

2010-07-01

Parallel excitation holds strong promises to mitigate the impact of large transmit B1 (B+1) distortion at very high magnetic field. Accelerated RF pulses, however, inherently tend to require larger values in RF peak power which may result in substantial increase in Specific Absorption Rate (SAR) in tissues, which is a constant concern for patient safety at very high field. In this study, we demonstrate adapted rate RF pulse design allowing for SAR reduction while preserving excitation target accuracy. Compared with other proposed implementations of adapted rate RF pulses, our approach is compatible with any k-space trajectories, does not require an analytical expression of the gradient waveform and can be used for large flip angle excitation. We demonstrate our method with numerical simulations based on electromagnetic modeling and we include an experimental verification of transmit pattern accuracy on an 8 transmit channel 9.4 T system.

A new maximum-likelihood change estimator for two-pass SAR coherent change detection

DOE PAGES

Wahl, Daniel E.; Yocky, David A.; Jakowatz, Jr., Charles V.; ...

2016-01-11

In previous research, two-pass repeat-geometry synthetic aperture radar (SAR) coherent change detection (CCD) predominantly utilized the sample degree of coherence as a measure of the temporal change occurring between two complex-valued image collects. Previous coherence-based CCD approaches tend to show temporal change when there is none in areas of the image that have a low clutter-to-noise power ratio. Instead of employing the sample coherence magnitude as a change metric, in this paper, we derive a new maximum-likelihood (ML) temporal change estimate—the complex reflectance change detection (CRCD) metric to be used for SAR coherent temporal change detection. The new CRCD estimatormore » is a surprisingly simple expression, easy to implement, and optimal in the ML sense. As a result, this new estimate produces improved results in the coherent pair collects that we have tested.« less

Ground Subsidence Monitoring with MT-InSAR and Mechanism Inversion Over Xi'an, China

NASA Astrophysics Data System (ADS)

Peng, M. M.; Zhao, C. Y.; Zhang, Q.; Zhang, J.; Liu, Y. Y.

2018-04-01

The ancient Xi'an, China, has been suffering severe land subsidence and ground fissure hazards since the 1960s, which has affected the safety of Subways. Multi-sensor SAR data are conducted to monitor the latest complex ground deformation and its influence on subway line No.3 over Xi'an. Annual deformation rates have been retrieved to reveal the spatiotemporal evolution of ground subsidence in Xi'an city from 2013 to 2017. Meanwhile, the correlation between land subsidence and ground fissures are analyzed by retrieving the deformation differences in both sides of the fissures. Besides, the deformation along subway line No. 3 is analyzed, and the fast deformation section is quantitatively studied. Finally, a flat lying sill model with distributed contractions is implemented to model the InSAR deformation over YHZ subsidence center, which manifests that the ground deformation is mainly caused by groundwater withdrawal.

The Vesuvius/Campi Flegrei Supersite: state of the art and future perspectives

NASA Astrophysics Data System (ADS)

Borgstrom, Sven; Del Gaudio, Carlo; De Martino, Prospero; Prats-Iraola, Pau; Nannini, Matteo; Vecchioli, Francesco; Minati, Federico; Costantini, Mario; Stramondo, Salvatore; Bignami, Christian; Polcari, Marco; Fabrizia Buongiorno, Maria; Silvestri, Malvina; Pepe, Antonio; Pepe, Susi; Solaro, Giuseppe; Tizzani, Pietro; Siniscalchi, Valeria

2017-04-01

The Vesuvius/Campi Flegrei Supersite was established in April, 2014 with the aim of improving monitoring and knowledge of one of the areas with the highest volcanic risk worldwide, due to the strong urbanization of the city of Naples and surroundings, lying between two active volcanoes: Vesuvius on the east and Campi Flegrei on the west, this latter with a recorded uplift of about 35 centimeters from 2011 to date. Such deformation suggested to the Italian Civil Protection Department (ICPD) to move from the base (green) alert level to attention (yellow) level in the framework of the Campi Flegrei National Emergency Plan. In the first 2014-2016 biennial period, relevant results were carried out by the Supersite Science Team, apart from the outcomes of the ESA-SEOM INSARAP (Sentinel-1 INSAR Performance Study with TOPS data) project. Results are mainly focused on InSAR (S1-A, CSK, TSX) data processing, exploiting both SBAS and PS Interferometry over the Neapolitan volcanoes, with generation of ground deformation time series and comparison between LOS/inverted (E-W, vertical) InSAR and geodetic data, these latter from the INGV-Osservatorio Vesuviano monitoring networks. After the first biennial period, a detailed report on the Supersite activities has been submitted and approved by CEOS for satellite data provision for the next 2016-2018 period. Besides the continuation of the work in progress, future steps will consist in a detailed InSAR study of Vesuvius, mainly in the upper coherent part of the volcano, in order to characterize the area of interest from the engineering geology point of view. Moreover, DLR is planning an airborne campaign with their F-SAR sensor over Campi Flegrei; the contribution from INGV-OV to this campaign will consist in validating InSAR measurements with continuous GPS (cGPS) data. The campaign will take place around May and then again in 2018. With regard to the societal benefits of the current activities of the Supersite, the main stakeholders benefitting from the results are the ICPD and, on a locale scale, the Regional Civil Protection of the Campania Region, besides the different Municipalities. Surveillance Reports have been produced for the ICPD on six-months and annual basis, showing regular updates on the state of the Neapolitan volcanoes. On a mid-term scale, the outcomes of the Supersite will be exploited in terms of technical contributions to the ICPD in setting up the updates of the National Emergency Plans for Vesuvius and Campi Flegrei areas.

InSAR data for geohazard assessment in UNESCO World Heritage sites: state-of-the-art and perspectives in the Copernicus era

NASA Astrophysics Data System (ADS)

Tapete, Deodato; Cigna, Francesca

2017-12-01

Protection of natural and cultural heritage is encompassed by the United Nations' 2030 Agenda for Sustainable Development and is among the innovative applications and services of the European Union's Earth Observation programme Copernicus. We are currently witnessing an increasing exploitation of Interferometric Synthetic Aperture Radar (InSAR) methods to assess geohazards affecting cultural heritage. This paper offers the first data mining exercise to identify InSAR geoinformation that is digitally available and/or published and that spatially includes one or more cultural, natural and mixed UNESCO World Heritage Site (WHS). The exercise focused on the 45 countries of geographical Europe, Turkey, Israel and the Russian Federation, and their 445 WHS of Outstanding Universal Value. We built a database of academic and grey literature collated via a Boolean search of the ISI Web of Science catalogue and systematic skim-reading to a total number of 280 publications as of the end of 2016. Over 460 InSAR open access digital datasets were also analysed. We found clusters of WHS covered by InSAR data in Italy, the Netherlands, western Germany, eastern Spain, Greece and the UK that match with the geographic distribution of InSAR expertise and geohazard hotspots. The existing stock of InSAR geoinformation already provides an overall WHS coverage of 36%, with similar proportion of available data for 'urban' (40%) and 'rural' (34%) WHS. The sites with the highest number of publications are historic city centres (e.g. Amsterdam, Athens, Barcelona, Lisbon, Paris, Rome), as well as Permanent Geohazard Supersites (e.g. Mt. Etna, Naples, Istanbul), where the impact of natural and/or anthropogenic processes is well known. First generation SAR data (mainly ERS-1/2) predominate in the literature with over 15 new publications/year since 2002, whilst second and third generation data show less pronounced rates since 2007 and 2014, respectively. The current engagement level of end-users appears still limited (less than 1% of publications involve heritage stakeholders), and a shared guidance on the use of InSAR for heritage practitioners does not exist yet. Towards the development of Copernicus' services and applications in support of cultural heritage preservation and management, our analysis contributes to: outline the existing capabilities; focus on requirements for bespoke InSAR-derived products and services; and consider possible implementation scenarios both in emergency and ordinary circumstances.

Expected Applications of the SRTM Data Within the Amazon Basin

NASA Astrophysics Data System (ADS)

Alsdorf, D.; Hess, L.; Melack, J.; Melack, J.; Dunne, T.; Dunne, T.; Mertes, L.; Ballantine, A.; Biggs, T.; Holmes, K.

2001-12-01

Using the SRTM data combined with additional SAR, optical, and ground based observations throughout the entire Amazon basin, we plan to (1) determine long-term landscape evolution using a stream channel incision and local uplift model, (2) apply a mass-flux model to estimate the Andean sediment supply, (3) characterize channel migration, (4) model topographically driven runoff and groundwater recharge to assess the rate of delivery of flood runoff to channels, and (5) quantify areas of basic vegetation types and their methane production. Presently, we have been using a high-resolution mosaic of JERS-1 SAR data until the Basin wide SRTM DEM is available. Stream networks automatically extracted from the mosaic have already been combined with interferometric SAR measurements of water level changes to yield a floodplain storage estimate. Furthermore, the mosaic has now been used to characterize regions of expected topographic ruggedness. The advent of the DEM will allow relationships to be developed between topographic slopes and measured concentrations and fluxes of dissolved inorganic material. Most significantly for SRTM DEM studies and as based on our SIR-C research, the C-band radar is backscattered from within the uppermost canopy. Thus to convert the DEM from canopy-top to expected ground heights we plan to use our classification methods to produce a map showing vegetation types and average heights which can be subtracted from the SRTM DEM.

LightSAR Pushes Both the Technology and the Economics

NASA Technical Reports Server (NTRS)

Bard, S.

1998-01-01

As part of the strategic plan for its Earth Science Enterprise, the U.S. National Aeronautics and Space Administration (NASA) is committed to fostering the development and prosperous use of imaging radar science and technology in both the public and private sectors.

Using autoregressive integrated moving average (ARIMA) models to predict and monitor the number of beds occupied during a SARS outbreak in a tertiary hospital in Singapore.

PubMed

Earnest, Arul; Chen, Mark I; Ng, Donald; Sin, Leo Yee

2005-05-11

The main objective of this study is to apply autoregressive integrated moving average (ARIMA) models to make real-time predictions on the number of beds occupied in Tan Tock Seng Hospital, during the recent SARS outbreak. This is a retrospective study design. Hospital admission and occupancy data for isolation beds was collected from Tan Tock Seng hospital for the period 14th March 2003 to 31st May 2003. The main outcome measure was daily number of isolation beds occupied by SARS patients. Among the covariates considered were daily number of people screened, daily number of people admitted (including observation, suspect and probable cases) and days from the most recent significant event discovery. We utilized the following strategy for the analysis. Firstly, we split the outbreak data into two. Data from 14th March to 21st April 2003 was used for model development. We used structural ARIMA models in an attempt to model the number of beds occupied. Estimation is via the maximum likelihood method using the Kalman filter. For the ARIMA model parameters, we considered the simplest parsimonious lowest order model. We found that the ARIMA (1,0,3) model was able to describe and predict the number of beds occupied during the SARS outbreak well. The mean absolute percentage error (MAPE) for the training set and validation set were 5.7% and 8.6% respectively, which we found was reasonable for use in the hospital setting. Furthermore, the model also provided three-day forecasts of the number of beds required. Total number of admissions and probable cases admitted on the previous day were also found to be independent prognostic factors of bed occupancy. ARIMA models provide useful tools for administrators and clinicians in planning for real-time bed capacity during an outbreak of an infectious disease such as SARS. The model could well be used in planning for bed-capacity during outbreaks of other infectious diseases as well.

Assessment of DInSAR Potential in Simulating Geological Subsurface Structure

NASA Astrophysics Data System (ADS)

Fouladi Moghaddam, N.; Rudiger, C.; Samsonov, S. V.; Hall, M.; Walker, J. P.; Camporese, M.

2013-12-01

High resolution geophysical surveys, including seismic, gravity, magnetic, etc., provide valuable information about subsurface structuring but they are very costly and time consuming with non-unique and sometimes conflicting interpretations. Several recent studies have examined the application of DInSAR to estimate surface deformation, monitor possible fault reactivation and constrain reservoir dynamic behaviour in geothermal and groundwater fields. The main focus of these studies was to generate an elevation map, which represents the reservoir extraction induced deformation. This research study, however, will focus on developing methods to simulate subsurface structuring and identify hidden faults/hydraulic barriers using DInSAR surface observations, as an innovative and cost-effective reconnaissance exploration tool for planning of seismic acquisition surveys in geothermal and Carbon Capture and Sequestration regions. By direct integration of various DInSAR datasets with overlapping temporal and spatial coverage we produce multi-temporal ground deformation maps with high resolution and precision to evaluate the potential of a new multidimensional MSBAS technique (Samsonov & d'Oreye, 2012). The technique is based on the Small Baseline Subset Algorithm (SBAS) that is modified to account for variation in sensor parameters. It allows integration of data from sensors with different wave-band, azimuth and incidence angles, different spatial and temporal sampling and resolutions. These deformation maps then will be used as an input for inverse modelling to simulate strain history and shallow depth structure. To achieve the main objective of our research, i.e. developing a method for coupled InSAR and geophysical observations and better understanding of subsurface structuring, comparing DInSAR inverse modelling results with previously provided static structural model will result in iteratively modified DInSAR structural model for adequate match with in situ observations. The newly developed and modified algorithm will then be applied in another part of the region where subsurface information is limited.

InSAR to support sustainable urbanization over compacting aquifers: The case of Toluca Valley, Mexico

NASA Astrophysics Data System (ADS)

Castellazzi, Pascal; Garfias, Jaime; Martel, Richard; Brouard, Charles; Rivera, Alfonso

2017-12-01

This paper illustrates how InSAR alone can be used to delineate potential ground fractures related to aquifer system compaction. An InSAR-derived ground fracturing map of the Toluca Valley, Mexico, is produced and validated through a field campaign. The results are of great interest to support sustainable urbanization and show that InSAR processing of open-access Synthetic Aperture Radar (SAR) data from the Sentinel-1 satellites can lead to reliable and cost-effective products directly usable by cities to help decision-making. The Toluca Valley Aquifer (TVA) sustains the water needs of two million inhabitants living within the valley, a growing industry, an intensively irrigated agricultural area, and 38% of the water needs of the megalopolis of Mexico City, located 40 km east of the valley. Ensuring water sustainability, infrastructure integrity, along with supporting the important economic and demographic growth of the region, is a major challenge for water managers and urban developers. This paper presents a long-term analysis of ground fracturing by interpreting 13 years of InSAR-derived ground displacement measurements. Small Baseline Subset (SBAS) and Persistent Scatterer Interferometry (PSI) techniques are applied over three SAR datasets totalling 93 acquisitions from Envisat, Radarsat-2, and Sentinel-1A satellites and covering the period from 2003 to 2016. From 2003 to 2016, groundwater level declines of up to 1.6 m/yr, land subsidence up to 77 mm/yr, and major infrastructure damages are observed. Groundwater level data show highly variable seasonal responses according to their connectivity to recharge areas. However, the trend of groundwater levels consistently range from -0.5 to -1.5 m/yr regardless of the well location and depth. By analysing the horizontal gradients of vertical land subsidence, we provide a potential ground fracture map to assist in future urban development planning in the Toluca Valley.

Deformation signals from InSAR time series analysis related to the 2007 and 2011 east rift zone intrusions at Kilauea Volcano, Hawaii

NASA Astrophysics Data System (ADS)

Baker, S.; Amelung, F.

2011-12-01

Located on the Big Island of Hawaii, Kilauea volcano is one of the most active volcanoes on Earth with continuous eruptive activity since 1983. The eruptive activity is predominately from the Pu'u O'o vent within the east rift zone, but periodic intrusions occur in the upper east rift zone between the summit and Pu'u O'o. These intrusions occur as dikes typically accompanied by fissure openings and eruptions of small volumes of lava. Interferometric synthetic aperture radar (InSAR) provides surface displacement measurements showing how the ground moves before, during, and after these intrusions. Given the recent increase in the number of active or planned SAR satellites and the more frequent repeat-pass times, InSAR is proving to be a valuable monitoring tool for volcanic hazards. Using data from Radarsat-1, Envisat, ALOS, and TerraSAR-X satellites, we generate line-of-sight InSAR time series using the small baseline subset (SBAS) which provides dense spatial and temporal coverage at Kilauea covering the 17 June 2007 and 5 March 2011 intrusions. For these two events, the summit caldera area switches from deflation to inflation months to years before both intrusions, and just prior to the intrusions we observe increased rates of inflation accompanied by elevated seismic activity in the upper east rift zone. Observations of the intrusion relate surface displacement and the response of the summit caldera area provide insight into the shallow magmatic system and the connectivity of the system. By combining InSAR time series with other geophysical data sets (such as seismic or GPS), we obtain more details about the associated hazard and a better understanding of the time-dependent relationship between what we are measuring and the controlling processes at the volcano.

Chandrayaan-2 dual-frequency SAR: Further investigation into lunar water and regolith

NASA Astrophysics Data System (ADS)

Putrevu, Deepak; Das, Anup; Vachhani, J. G.; Trivedi, Sanjay; Misra, Tapan

2016-01-01

The Space Applications Centre (SAC), one of the major centers of the Indian Space Research Organization (ISRO), is developing a high resolution, dual-frequency Synthetic Aperture Radar as a science payload on Chandrayaan-2, ISRO's second moon mission. With this instrument, ISRO aims to further the ongoing studies of the data from S-band MiniSAR onboard Chandrayaan-1 (India) and the MiniRF of Lunar Reconnaissance Orbiter (USA). The SAR instrument has been configured to operate with both L- and S-bands, sharing a common antenna. The S-band SAR will provide continuity to the MiniSAR data, whereas L-band is expected to provide deeper penetration of the lunar regolith. The system will have a selectable slant-range resolution from 2 m to 75 m, along with standalone (L or S) and simultaneous (L and S) modes of imaging. Various features of the instrument like hybrid and full-polarimetry, a wide range of imaging incidence angles (∼10° to ∼35°) and the high spatial resolution will greatly enhance our understanding of surface properties especially in the polar regions of the Moon. The system will also help in resolving some of the ambiguities in interpreting high values of Circular Polarization Ratio (CPR) observed in MiniSAR data. The added information from full-polarimetric data will allow greater confidence in the results derived particularly in detecting the presence (and estimating the quantity) of water-ice in the polar craters. Being a planetary mission, the L&S-band SAR for Chandrayaan-2 faced stringent limits on mass, power and data rate (15 kg, 100 W and 160 Mbps respectively), irrespective of any of the planned modes of operation. This necessitated large-scale miniaturization, extensive use of on-board processing, and devices and techniques to conserve power. This paper discusses the scientific objectives which drive the requirement of a lunar SAR mission and presents the configuration of the instrument, along with a description of a number of features of the system, designed to meet the science goals with optimum resources.

InSAR detection of aquifer recovery: Case studies of Koehn Lake (central California) and Lone Tree Gold Mine (Basin and Range)

NASA Astrophysics Data System (ADS)

Wdowinski, S.; Greene, F.; Amelung, F.

2013-12-01

Anthropogenic intervention in groundwater flow and aquifer storage often results in vertical movements of Earth's surface, which are well detected by InSAR observations. Most anthropogenic intervention occurs due to groundwater extraction for both agriculture and human consumption and results in land subsidence. However in some cases, ending anthropogenic intervention can lead to aquifer recovery and, consequently, surface uplift. In this study we present two such cases of aquifer recovery. The first case is the aquifer beneath Koehn Lake in Central California, which was overused to meet agricultural demands until the 1990's. The second case is the Lone Tree Gold Mine in Nevada that during active mining in the 1991-2006 groundwater pumping disrupted the aquifer and cause subsidence. But after mining ceased, groundwater flow was recovered and resulted in uplift. In both cases we studied the surface uplift using InSAR time series observations. We conduct an ERS and Envisat InSAR survey over Koehn Lake in California and Lone Tree Gold Mine in Nevada between 1992 and 2010. We followed the SBAS algorithm to generate a time-series of ground displacements and average velocities of pixels, which remain coherent through time in the SAR dataset. A total of 100 and 80 combined ERS and Envisat SAR dates are inverted for Koehn Lake and Lone Tree Gold Mine respectively. Results for the Koehn Lake area indicate a rapid uplift of about 3.5 mm/yr between 1992-2000 and a slower uplift rate of 1.6 mm/yr between 2000-2004, suggesting a decrease in the recovery process. The observed uplift correlates well with groundwater level increase in the Koehn Lake area. Results for the Lone Tree Gold Mine show a constant subsidence (~ 1 cm/yr) due to groundwater extraction between 1992-2006, but uplift of ~1 cm/yr since the beginning of 2007. In both case studies, InSAR observations reveal that the aquifer recovery is accompanied by surface uplift. We plan to use the InSAR observations and the groundwater level records to model and better understand aquifer recovery processes.

Analysis of the fractal dimension of volcano geomorphology through Synthetic Aperture Radar (SAR) amplitude images acquired in C and X band.

NASA Astrophysics Data System (ADS)

Pepe, S.; Di Martino, G.; Iodice, A.; Manzo, M.; Pepe, A.; Riccio, D.; Ruello, G.; Sansosti, E.; Tizzani, P.; Zinno, I.

2012-04-01

In the last two decades several aspects relevant to volcanic activity have been analyzed in terms of fractal parameters that effectively describe natural objects geometry. More specifically, these researches have been aimed at the identification of (1) the power laws that governed the magma fragmentation processes, (2) the energy of explosive eruptions, and (3) the distribution of the associated earthquakes. In this paper, the study of volcano morphology via satellite images is dealt with; in particular, we use the complete forward model developed by some of the authors (Di Martino et al., 2012) that links the stochastic characterization of amplitude Synthetic Aperture Radar (SAR) images to the fractal dimension of the imaged surfaces, modelled via fractional Brownian motion (fBm) processes. Based on the inversion of such a model, a SAR image post-processing has been implemented (Di Martino et al., 2010), that allows retrieving the fractal dimension of the observed surfaces, dictating the distribution of the roughness over different spatial scales. The fractal dimension of volcanic structures has been related to the specific nature of materials and to the effects of active geodynamic processes. Hence, the possibility to estimate the fractal dimension from a single amplitude-only SAR image is of fundamental importance for the characterization of volcano structures and, moreover, can be very helpful for monitoring and crisis management activities in case of eruptions and other similar natural hazards. The implemented SAR image processing performs the extraction of the point-by-point fractal dimension of the scene observed by the sensor, providing - as an output product - the map of the fractal dimension of the area of interest. In this work, such an analysis is performed on Cosmo-SkyMed, ERS-1/2 and ENVISAT images relevant to active stratovolcanoes in different geodynamic contexts, such as Mt. Somma-Vesuvio, Mt. Etna, Vulcano and Stromboli in Southern Italy, Shinmoe in Japan, Merapi in Indonesia. Preliminary results reveal that the fractal dimension of natural areas, being related only to the roughness of the observed surface, is very stable as the radar illumination geometry, the resolution and the wavelength change, thus holding a very unique property in SAR data inversion. Such a behavior is not verified in case of non-natural objects. As a matter of fact, when the fractal estimation is performed in the presence of either man-made objects or SAR image features depending on geometrical distortions due to the SAR system acquisition (i.e. layover, shadowing), fractal dimension (D) values outside the range of fractality of natural surfaces (2 < D < 3) are retrieved. These non-fractal characteristics show to be heavily dependent on sensor acquisition parameters (e.g. view angle, resolution). In this work, the behaviour of the maps generated starting from the C- and X- band SAR data, relevant to all the considered volcanoes, is analyzed: the distribution of the obtained fractal dimension values is investigated on different zones of the maps. In particular, it is verified that the fore-slope and back-slope areas of the image share a very similar fractal dimension distribution that is placed around the mean value of D=2.3. We conclude that, in this context, the fractal dimension could be considered as a signature of the identification of the volcano growth as a natural process. The COSMO-SkyMed data used in this study have been processed at IREA-CNR within the SAR4Volcanoes project under Italian Space Agency agreement n. I/034/11/0.

Handling the Diversity in the Coming Flood of InSAR Data with the InSAR Scientific Computing Environment

NASA Astrophysics Data System (ADS)

Rosen, P. A.; Gurrola, E. M.; Sacco, G. F.; Agram, P. S.; Lavalle, M.; Zebker, H. A.

2014-12-01

The NASA ESTO-developed InSAR Scientific Computing Environment (ISCE) provides acomputing framework for geodetic image processing for InSAR sensors that ismodular, flexible, and extensible, enabling scientists to reduce measurementsdirectly from a diverse array of radar satellites and aircraft to newgeophysical products. ISCE can serve as the core of a centralized processingcenter to bring Level-0 raw radar data up to Level-3 data products, but isadaptable to alternative processing approaches for science users interested innew and different ways to exploit mission data. This is accomplished throughrigorous componentization of processing codes, abstraction and generalization ofdata models, and a xml-based input interface with multi-level prioritizedcontrol of the component configurations depending on the science processingcontext. The proposed NASA-ISRO SAR (NISAR) Mission would deliver data ofunprecedented quantity and quality, making possible global-scale studies inclimate research, natural hazards, and Earth's ecosystems. ISCE is planned tobecome a key element in processing projected NISAR data into higher level dataproducts, enabling a new class of analyses that take greater advantage of thelong time and large spatial scales of these new data than current approaches.NISAR would be but one mission in a constellation of radar satellites in thefuture delivering such data. ISCE has been incorporated into two prototypecloud-based systems that have demonstrated its elasticity to addressing largerdata processing problems in a "production" context and its ability to becontrolled by individual science users on the cloud for large data problems.

First In-Orbit Experience of TerraSAR-X Flight Dynamics Operations

NASA Technical Reports Server (NTRS)

Kahle, R.; Kazeminejad, B.; Kirschner, M.; Yoon, Y.; Kiehling, R.; D'Amico, S.

2007-01-01

TerraSAR-X is an advanced synthetic aperture radar satellite system for scientific and commercial applications that is realized in a public-private partnership between the German Aerospace Center (DLR) and the Astrium GmbH. TerraSAR-X was launched at June 15, 2007 on top of a Russian DNEPR-1 rocket into a 514 km sun-synchronous dusk-dawn orbit with an 11-day repeat cycle and will be operated for a period of at least 5 years during which it will provide high resolution SAR-data in the X-band. Due to the objectives of the interferometric campaigns the satellite has to comply to tight orbit control requirements, which are formulated in the form of a 250 m toroidal tube around a pre-flight determined reference trajectory (see [1] for details). The acquisition of the reference orbit was one of the main and key activities during the Launch and Early Orbit Phase (LEOP) and had to compensate for both injection errors and spacecraft safe mode attitude control thruster activities. The paper summarizes the activities of GSOC flight dynamics team during both LEOP and early Commissioning Phase, where the main tasks have been 1) the first-acquisition support via angle-tracking and GPS-based orbit determination, 2) maneuver planning for target orbit acquisition and maintenance, and 3) precise orbit and attitude determination for SAR processing support. Furthermore, a presentation on the achieved results and encountered problems will be addressed.

a Hybrid Method in Vegetation Height Estimation Using Polinsar Images of Campaign Biosar

NASA Astrophysics Data System (ADS)

Dehnavi, S.; Maghsoudi, Y.

2015-12-01

Recently, there have been plenty of researches on the retrieval of forest height by PolInSAR data. This paper aims at the evaluation of a hybrid method in vegetation height estimation based on L-band multi-polarized air-borne SAR images. The SAR data used in this paper were collected by the airborne E-SAR system. The objective of this research is firstly to describe each interferometry cross correlation as a sum of contributions corresponding to single bounce, double bounce and volume scattering processes. Then, an ESPIRIT (Estimation of Signal Parameters via Rotational Invariance Techniques) algorithm is implemented, to determine the interferometric phase of each local scatterer (ground and canopy). Secondly, the canopy height is estimated by phase differencing method, according to the RVOG (Random Volume Over Ground) concept. The applied model-based decomposition method is unrivaled, as it is not limited to specific type of vegetation, unlike the previous decomposition techniques. In fact, the usage of generalized probability density function based on the nth power of a cosine-squared function, which is characterized by two parameters, makes this method useful for different vegetation types. Experimental results show the efficiency of the approach for vegetation height estimation in the test site.

Investigation of Joint Visibility Between SAR and Optical Images of Urban Environments

NASA Astrophysics Data System (ADS)

Hughes, L. H.; Auer, S.; Schmitt, M.

2018-05-01

In this paper, we present a work-flow to investigate the joint visibility between very-high-resolution SAR and optical images of urban scenes. For this task, we extend the simulation framework SimGeoI to enable a simulation of individual pixels rather than complete images. Using the extended SimGeoI simulator, we carry out a case study using a TerraSAR-X staring spotlight image and a Worldview-2 panchromatic image acquired over the city of Munich, Germany. The results of this study indicate that about 55 % of the scene are visible in both images and are thus suitable for matching and data fusion endeavours, while about 25 % of the scene are affected by either radar shadow or optical occlusion. Taking the image acquisition parameters into account, our findings can provide support regarding the definition of upper bounds for image fusion tasks, as well as help to improve acquisition planning with respect to different application goals.

A surgical robot with augmented reality visualization for stereoelectroencephalography electrode implantation.

PubMed

Zeng, Bowei; Meng, Fanle; Ding, Hui; Wang, Guangzhi

2017-08-01

Using existing stereoelectroencephalography (SEEG) electrode implantation surgical robot systems, it is difficult to intuitively validate registration accuracy and display the electrode entry points (EPs) and the anatomical structure around the electrode trajectories in the patient space to the surgeon. This paper proposes a prototype system that can realize video see-through augmented reality (VAR) and spatial augmented reality (SAR) for SEEG implantation. The system helps the surgeon quickly and intuitively confirm the registration accuracy, locate EPs and visualize the internal anatomical structure in the image space and patient space. We designed and developed a projector-camera system (PCS) attached to the distal flange of a robot arm. First, system calibration is performed. Second, the PCS is used to obtain the point clouds of the surface of the patient's head, which are utilized for patient-to-image registration. Finally, VAR is produced by merging the real-time video of the patient and the preoperative three-dimensional (3D) operational planning model. In addition, SAR is implemented by projecting the planning electrode trajectories and local anatomical structure onto the patient's scalp. The error of registration, the electrode EPs and the target points are evaluated on a phantom. The fiducial registration error is [Formula: see text] mm (max 1.22 mm), and the target registration error is [Formula: see text] mm (max 1.18 mm). The projection overlay error is [Formula: see text] mm, and the TP error after the pre-warped projection is [Formula: see text] mm. The TP error caused by a surgeon's viewpoint deviation is also evaluated. The presented system can help surgeons quickly verify registration accuracy during SEEG procedures and can provide accurate EP locations and internal structural information to the surgeon. With more intuitive surgical information, the surgeon may have more confidence and be able to perform surgeries with better outcomes.

Public health human resources: a comparative analysis of policy documents in two Canadian provinces

PubMed Central

2014-01-01

Background Amidst concerns regarding the capacity of the public health system to respond rapidly and appropriately to threats such as pandemics and terrorism, along with changing population health needs, governments have focused on strengthening public health systems. A key factor in a robust public health system is its workforce. As part of a nationally funded study of public health renewal in Canada, a policy analysis was conducted to compare public health human resources-relevant documents in two Canadian provinces, British Columbia (BC) and Ontario (ON), as they each implement public health renewal activities. Methods A content analysis of policy and planning documents from government and public health-related organizations was conducted by a research team comprised of academics and government decision-makers. Documents published between 2003 and 2011 were accessed (BC = 27; ON = 20); documents were either publicly available or internal to government and excerpted with permission. Documentary texts were deductively coded using a coding template developed by the researchers based on key health human resources concepts derived from two national policy documents. Results Documents in both provinces highlighted the importance of public health human resources planning and policies; this was particularly evident in early post-SARS documents. Key thematic areas of public health human resources identified were: education, training, and competencies; capacity; supply; intersectoral collaboration; leadership; public health planning context; and priority populations. Policy documents in both provinces discussed the importance of an educated, competent public health workforce with the appropriate skills and competencies for the effective and efficient delivery of public health services. Conclusion This policy analysis identified progressive work on public health human resources policy and planning with early documents providing an inventory of issues to be addressed and later documents providing evidence of beginning policy development and implementation. While many similarities exist between the provinces, the context distinctive to each province has influenced and shaped how they have focused their public health human resources policies. PMID:24564931

Public health human resources: a comparative analysis of policy documents in two Canadian provinces.

PubMed

Regan, Sandra; MacDonald, Marjorie; Allan, Diane E; Martin, Cheryl; Peroff-Johnston, Nancy

2014-02-24

Amidst concerns regarding the capacity of the public health system to respond rapidly and appropriately to threats such as pandemics and terrorism, along with changing population health needs, governments have focused on strengthening public health systems. A key factor in a robust public health system is its workforce. As part of a nationally funded study of public health renewal in Canada, a policy analysis was conducted to compare public health human resources-relevant documents in two Canadian provinces, British Columbia (BC) and Ontario (ON), as they each implement public health renewal activities. A content analysis of policy and planning documents from government and public health-related organizations was conducted by a research team comprised of academics and government decision-makers. Documents published between 2003 and 2011 were accessed (BC = 27; ON = 20); documents were either publicly available or internal to government and excerpted with permission. Documentary texts were deductively coded using a coding template developed by the researchers based on key health human resources concepts derived from two national policy documents. Documents in both provinces highlighted the importance of public health human resources planning and policies; this was particularly evident in early post-SARS documents. Key thematic areas of public health human resources identified were: education, training, and competencies; capacity; supply; intersectoral collaboration; leadership; public health planning context; and priority populations. Policy documents in both provinces discussed the importance of an educated, competent public health workforce with the appropriate skills and competencies for the effective and efficient delivery of public health services. This policy analysis identified progressive work on public health human resources policy and planning with early documents providing an inventory of issues to be addressed and later documents providing evidence of beginning policy development and implementation. While many similarities exist between the provinces, the context distinctive to each province has influenced and shaped how they have focused their public health human resources policies.

ISCE: A Modular, Reusable Library for Scalable SAR/InSAR Processing

NASA Astrophysics Data System (ADS)

Agram, P. S.; Lavalle, M.; Gurrola, E. M.; Sacco, G. F.; Rosen, P. A.

2016-12-01

Traditional community SAR/InSAR processing software tools have primarily focused on differential interferometry and Solid Earth applications. The InSAR Scientific Computing Environment (ISCE) was specifically designed to support the Earth Sciences user community as well as large scale operational processing tasks, thanks to its two-layered (Python+C/Fortran) architecture and modular framework. ISCE is freely distributed as a source tarball, allowing advanced users to modify and extend it for their research purposes and developing exploratory applications, while providing a relatively simple user interface for novice users to perform routine data analysis efficiently. Modular design of the ISCE library also enables easier development of applications to address the needs of Ecosystems, Cryosphere and Disaster Response communities in addition to the traditional Solid Earth applications. In this talk, we would like to emphasize the broader purview of the ISCE library and some of its unique features that sets it apart from other freely available community software like GMTSAR and DORIS, including: Support for multiple geometry regimes - Native Doppler (ALOS-1) as well Zero Doppler (ESA missions) systems. Support for data acquired by airborne platforms - e.g, JPL's UAVSAR and AirMOSS, DLR's F-SAR. Radiometric Terrain Correction - Auxiliary output layers from the geometry modules include projection angles, incidence angles, shadow-layover masks. Dense pixel offsets - Parallelized amplitude cross correlation for cryosphere / ionospheric correction applications. Rubber sheeting - Pixel-by-pixel offsets fields for resampling slave imagery for geometric co-registration/ ionospheric corrections. Preliminary Tandem-X processing support - Bistatic geometry modules. Extensibility to support other non-Solid Earth missions - Modules can be directly adopted for use with other SAR missions, e.g., SWOT. Preliminary support for multi-dimensional data products- multi-polarization, multi-frequency, multi-temporal, multi-baseline stacks via the PLANT and GIAnT toolboxes. Rapid prototyping - Geometry manipulation functionality at the python level allows users to prototype and test processing modules at the interpreter level before optimal implementation in C/C++/Fortran.

Linking species richness curves from non-contiguous sampling to contiguous-nested SAR: An empirical study

NASA Astrophysics Data System (ADS)

Lazarina, Maria; Kallimanis, Athanasios S.; Pantis, John D.; Sgardelis, Stefanos P.

2014-11-01

The species-area relationship (SAR) is one of the few generalizations in ecology. However, many different relationships are denoted as SARs. Here, we empirically evaluated the differences between SARs derived from nested-contiguous and non-contiguous sampling designs, using plants, birds and butterflies datasets from Great Britain, Greece, Massachusetts, New York and San Diego. The shape of SAR depends on the sampling scheme, but there is little empirical documentation on the magnitude of the deviation between different types of SARs and the factors affecting it. We implemented a strictly nested sampling design to construct nested-contiguous SAR (SACR), and systematic nested but non-contiguous, and random designs to construct non-contiguous species richness curves (SASRs for systematic and SACs for random designs) per dataset. The SACR lay below any SASR and most of the SACs. The deviation between them was related to the exponent f of the power law relationship between sampled area and extent. The lower the exponent f, the higher was the deviation between the curves. We linked SACR to SASR and SAC through the concept of "effective" area (Ae), i.e. the nested-contiguous area containing equal number of species with the accumulated sampled area (AS) of a non-contiguous sampling. The relationship between effective and sampled area was modeled as log(Ae) = klog(AS). A Generalized Linear Model was used to estimate the values of k from sampling design and dataset properties. The parameter k increased with the average distance between samples and with beta diversity, while k decreased with f. For both systematic and random sampling, the model performed well in predicting effective area in both the training set and in the test set which was totally independent from the training one. Through effective area, we can link different types of species richness curves based on sampling design properties, sampling effort, spatial scale and beta diversity patterns.

COSMO-SkyMed and GIS applications

NASA Astrophysics Data System (ADS)

Milillo, Pietro; Sole, Aurelia; Serio, Carmine

2013-04-01

Geographic Information Systems (GIS) and Remote Sensing have become key technology tools for the collection, storage and analysis of spatially referenced data. Industries that utilise these spatial technologies include agriculture, forestry, mining, market research as well as the environmental analysis . Synthetic Aperture Radar (SAR) is a coherent active sensor operating in the microwave band which exploits relative motion between antenna and target in order to obtain a finer spatial resolution in the flight direction exploiting the Doppler effect. SAR have wide applications in Remote Sensing such as cartography, surface deformation detection, forest cover mapping, urban planning, disasters monitoring , surveillance etc… The utilization of satellite remote sensing and GIS technology for this applications has proven to be a powerful and effective tool for environmental monitoring. Remote sensing techniques are often less costly and time-consuming for large geographic areas compared to conventional methods, moreover GIS technology provides a flexible environment for, analyzing and displaying digital data from various sources necessary for classification, change detection and database development. The aim of this work si to illustrate the potential of COSMO-SkyMed data and SAR applications in a GIS environment, in particular a demostration of the operational use of COSMO-SkyMed SAR data and GIS in real cases will be provided for what concern DEM validation, river basin estimation, flood mapping and landslide monitoring.

Real-Time Spaceborne Synthetic Aperture Radar Float-Point Imaging System Using Optimized Mapping Methodology and a Multi-Node Parallel Accelerating Technique

PubMed Central

Li, Bingyi; Chen, Liang; Yu, Wenyue; Xie, Yizhuang; Bian, Mingming; Zhang, Qingjun; Pang, Long

2018-01-01

With the development of satellite load technology and very large-scale integrated (VLSI) circuit technology, on-board real-time synthetic aperture radar (SAR) imaging systems have facilitated rapid response to disasters. A key goal of the on-board SAR imaging system design is to achieve high real-time processing performance under severe size, weight, and power consumption constraints. This paper presents a multi-node prototype system for real-time SAR imaging processing. We decompose the commonly used chirp scaling (CS) SAR imaging algorithm into two parts according to the computing features. The linearization and logic-memory optimum allocation methods are adopted to realize the nonlinear part in a reconfigurable structure, and the two-part bandwidth balance method is used to realize the linear part. Thus, float-point SAR imaging processing can be integrated into a single Field Programmable Gate Array (FPGA) chip instead of relying on distributed technologies. A single-processing node requires 10.6 s and consumes 17 W to focus on 25-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384. The design methodology of the multi-FPGA parallel accelerating system under the real-time principle is introduced. As a proof of concept, a prototype with four processing nodes and one master node is implemented using a Xilinx xc6vlx315t FPGA. The weight and volume of one single machine are 10 kg and 32 cm × 24 cm × 20 cm, respectively, and the power consumption is under 100 W. The real-time performance of the proposed design is demonstrated on Chinese Gaofen-3 stripmap continuous imaging. PMID:29495637

Vessel Classification in Cosmo-Skymed SAR Data Using Hierarchical Feature Selection

NASA Astrophysics Data System (ADS)

Makedonas, A.; Theoharatos, C.; Tsagaris, V.; Anastasopoulos, V.; Costicoglou, S.

2015-04-01

SAR based ship detection and classification are important elements of maritime monitoring applications. Recently, high-resolution SAR data have opened new possibilities to researchers for achieving improved classification results. In this work, a hierarchical vessel classification procedure is presented based on a robust feature extraction and selection scheme that utilizes scale, shape and texture features in a hierarchical way. Initially, different types of feature extraction algorithms are implemented in order to form the utilized feature pool, able to represent the structure, material, orientation and other vessel type characteristics. A two-stage hierarchical feature selection algorithm is utilized next in order to be able to discriminate effectively civilian vessels into three distinct types, in COSMO-SkyMed SAR images: cargos, small ships and tankers. In our analysis, scale and shape features are utilized in order to discriminate smaller types of vessels present in the available SAR data, or shape specific vessels. Then, the most informative texture and intensity features are incorporated in order to be able to better distinguish the civilian types with high accuracy. A feature selection procedure that utilizes heuristic measures based on features' statistical characteristics, followed by an exhaustive research with feature sets formed by the most qualified features is carried out, in order to discriminate the most appropriate combination of features for the final classification. In our analysis, five COSMO-SkyMed SAR data with 2.2m x 2.2m resolution were used to analyse the detailed characteristics of these types of ships. A total of 111 ships with available AIS data were used in the classification process. The experimental results show that this method has good performance in ship classification, with an overall accuracy reaching 83%. Further investigation of additional features and proper feature selection is currently in progress.

Development of Oil Spill Monitoring System for the Black Sea, Caspian Sea and the Barents/Kara Seas (DEMOSS)

NASA Astrophysics Data System (ADS)

Sandven, Stein; Kudriavtsev, Vladimir; Malinovsky, Vladimir; Stanovoy, Vladimir

2008-01-01

DEMOSS will develop and demonstrate elements of a marine oil spill detection and prediction system based on satellite Synthetic Aperture Radar (SAR) and other space data. In addition, models for prediction of sea surface pollution drift will be developed and tested. The project implements field experiments to study the effect of artificial crude oil and oil derivatives films on short wind waves and multi-frequency (Ka-, Ku-, X-, and C-band) dual polarization radar backscatter power and Doppler shift at different wind and wave conditions. On the basis of these and other available experimental data, the present model of short wind waves and radar scattering will be improved and tested.A new approach for detection and quantification of the oil slicks/spills in satellite SAR images is developed that can discriminate human oil spills from biogenic slicks and look-alikes in the SAR images. New SAR images are obtained in coordination with the field experiments to test the detection algorithm. Satellite SAR images from archives as well as from new acquisitions will be analyzed for the Black/Caspian/Kara/Barents seas to investigate oil slicks/spills occurrence statistics.A model for oil spills/slicks transport and evolution is developed and tested in ice-infested arctic seas, including the Caspian Sea. Case studies using the model will be conducted to simulate drift and evolution of oil spill events observed in SAR images. The results of the project will be disseminated via scientific publications and by demonstration to users and agencies working with marine monitoring. The project lasts for two years (2007 - 2009) and is funded under INTAS Thematic Call with ESA 2006.

InSAR Scientific Computing Environment

NASA Astrophysics Data System (ADS)

Gurrola, E. M.; Rosen, P. A.; Sacco, G.; Zebker, H. A.; Simons, M.; Sandwell, D. T.

2010-12-01

The InSAR Scientific Computing Environment (ISCE) is a software development effort in its second year within the NASA Advanced Information Systems and Technology program. The ISCE will provide a new computing environment for geodetic image processing for InSAR sensors that will enable scientists to reduce measurements directly from radar satellites and aircraft to new geophysical products without first requiring them to develop detailed expertise in radar processing methods. The environment can serve as the core of a centralized processing center to bring Level-0 raw radar data up to Level-3 data products, but is adaptable to alternative processing approaches for science users interested in new and different ways to exploit mission data. The NRC Decadal Survey-recommended DESDynI mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystem. The InSAR Scientific Computing Environment is planned to become a key element in processing DESDynI data into higher level data products and it is expected to enable a new class of analyses that take greater advantage of the long time and large spatial scales of these new data, than current approaches. At the core of ISCE is both legacy processing software from the JPL/Caltech ROI_PAC repeat-pass interferometry package as well as a new InSAR processing package containing more efficient and more accurate processing algorithms being developed at Stanford for this project that is based on experience gained in developing processors for missions such as SRTM and UAVSAR. Around the core InSAR processing programs we are building object-oriented wrappers to enable their incorporation into a more modern, flexible, extensible software package that is informed by modern programming methods, including rigorous componentization of processing codes, abstraction and generalization of data models, and a robust, intuitive user interface with graduated exposure to the levels of sophistication, allowing novices to apply it readily for common tasks and experienced users to mine data with great facility and flexibility. The environment is designed to easily allow user contributions, enabling an open source community to extend the framework into the indefinite future. In this paper we briefly describe both the legacy and the new core processing algorithms and their integration into the new computing environment. We describe the ISCE component and application architecture and the features that permit the desired flexibility, extensibility and ease-of-use. We summarize the state of progress of the environment and the plans for completion of the environment and for its future introduction into the radar processing community.

SAR-EDU - An education initiative for applied Synthetic Aperture Radar remote sensing

NASA Astrophysics Data System (ADS)

Eckardt, Robert; Richter, Nicole; Auer, Stefan; Eineder, Michael; Roth, Achim; Hajnsek, Irena; Walter, Diana; Braun, Matthias; Motagh, Mahdi; Pathe, Carsten; Pleskachevsky, Andrey; Thiel, Christian; Schmullius, Christiane

2013-04-01

Since the 1970s, radar remote sensing techniques have evolved rapidly and are increasingly employed in all fields of earth sciences. Applications are manifold and still expanding due to the continuous development of new instruments and missions as well as the availability of very high-quality data. The trend worldwide is towards operational employment of the various algorithms and methods that have been developed. However, the utilization of operational services does not keep up yet with the rate of technical developments and the improvements in sensor technology. With the enhancing availability and variety of space borne Synthetic Aperture Radar (SAR) data and a growing number of analysis algorithms the need for a vital user community is increasing. Therefore the German Aerospace Center (DLR) together with the Friedrich-Schiller-University Jena (FSU) and the Technical University Munich (TUM) launched the education initiative SAR-EDU. The aim of the project is to facilitate access to expert knowledge in the scientific field of radar remote sensing. Within this effort a web portal will be created to provide seminar material on SAR basics, methods and applications to support both, lecturers and students. The overall intension of the project SAR-EDU is to provide seminar material for higher education in radar remote sensing covering the topic holistically from the very basics to the most advanced methods and applications that are available. The principles of processing and interpreting SAR data are going to be taught using test data sets and open-source as well as commercial software packages. The material that is provided by SAR-EDU will be accessible at no charge from a DLR web portal. The educational tool will have a modular structure, consisting of separate modules that broach the issue of a particular topic. The aim of the implementation of SAR-EDU as application-oriented radar remote sensing educational tool is to advocate the development and wider use of operational services on the base of pre-existing algorithms and sensors on the one hand, and to aid the extension of radar remote sensing techniques to a broader field of application on the other. SAR-EDU therefore combines the knowledge, expertise and experience of an excellent German consortium.

Improved Oceanographic Measurements with CryoSat SAR Altimetry: Applications to the Coastal Zone and Arctic

NASA Astrophysics Data System (ADS)

Cotton, D.; Garcia, P. N.; Cancet, M.; Andersen, O.; Stenseng, L.; Martin, F.; Cipollini, P.; Calafat, F. M.; Passaro, M.; Restano, M.; Ambrozio, A.; Benveniste, J.

2016-08-01

The ESA CryoSat-2 mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar (SAR) mode. Although the prime objective of the CryoSat-2 mission is dedicated to monitoring land and marine ice, the SAR mode capability of the CryoSat-2 SIRAL altimeter also presents significant potential benefits for ocean applications including improved range precision and finer along track spatial resolution.The "CryoSat Plus for Oceans" (CP4O) project, supported by the ESA Support to Science Element (STSE) Programme and by CNES, was dedicated to the exploitation of CryoSat-2 data over the open and coastal ocean. The general objectives of the CP4O project were: to build a sound scientific basis for new oceanographic applications of CryoSat-2 data; to generate and evaluate new methods and products that will enable the full exploitation of the capabilities of the CryoSat-2 SIRAL altimeter, and to ensure that the scientific return of the CryoSat-2 mission is maximised. Cotton et al, (2015) is the final report on this work.However, whilst the results from CP4O were highly promising and confirmed the potential of SAR altimetry to support new scientific and operational oceanographic applications, it was also apparent that further work was needed in some key areas to fully realise the original project objectives. Thus additional work in four areas has been supported by ESA under a Contract Change Notice:• Developments in SARin data processing for Coastal Altimetry (isardSAT).• Implementation of a Regional Tidal Atlas for the Arctic Ocean (Noveltis and DTU Space).• Improvements to the SAMOSA re-tracker: Implementation and Evaluation- Optimised Thermal Noise Estimation. (Starlab and SatOC).• Extended evaluation of CryoSat-2 SAR data for Coastal Applications (NOC).This work was managed by SatOC. The results of this work are summarized here. Detailed information regarding the CP4O project can be found at: http://www.satoc.eu/projects/CP4O/

Improving older adults' knowledge and practice of preventive measures through a telephone health education during the SARS epidemic in Hong Kong: a pilot study.

PubMed

Chan, Sophia S C; So, Winnie K W; Wong, David C N; Lee, Angel C K; Tiwari, Agnes

2007-09-01

The outbreak of severe acute respiratory syndrome (SARS) in Hong Kong posed many challenges for health promotion activities among a group of older adults with low socio-economic status (SES). With concerns that this vulnerable group could be at higher risk of contracting the disease or spreading it to others, the implementation of health promotion activities appropriate to this group was considered to be essential during the epidemic. To assess the effectiveness of delivering a telephone health education programme dealing with anxiety levels, and knowledge and practice of measures to prevent transmission of SARS among a group of older adults with low SES. Pretest/posttest design. Subjects were recruited from registered members of a government subsidized social service center in Hong Kong and living in low-cost housing estates. The eligibility criteria were: (1) aged 55 or above; (2) able to speak Cantonese; (3) no hearing impairment, and (4) reachable by telephone. Of the 295 eligible subjects, 122 older adults completed the whole study. The interviewers approached all eligible subjects by telephone during the period of 15-25 May 2003. After obtaining the participants' verbal consent, the interviewer collected baseline data by use of a questionnaire and implemented a health education programme. A follow-up telephone call was made a week later using the same questionnaire. The level of anxiety was lowered (t=3.28, p<0.001), and knowledge regarding the transmission routes of droplets (p<0.001) and urine and feces (p<0.01) were improved after the intervention. Although statistical significant difference was found in the practice of identified preventive measures before and after intervention, influence on behavioral changes needed further exploration. The telephone health education seemed to be effective in relieving anxiety and improving knowledge of the main transmission routes of SARS in this group, but not the practice of preventing SARS. Telephone contact appears to be a practical way of providing health education to vulnerable groups when face-to-face measure is not feasible and may be useful in raising health awareness during future outbreaks of emerging infections.

Quantitative evaluation of infection control models in the prevention of nosocomial transmission of SARS virus to healthcare workers: implication to nosocomial viral infection control for healthcare workers.

PubMed

Yen, Muh-Yong; Lu, Yun-Ching; Huang, Pi-Hsiang; Chen, Chen-Ming; Chen, Yee-Chun; Lin, Yusen E

2010-07-01

Healthcare workers (HCWs) are at high risk of acquiring emerging infections while caring for patients, as has been shown in the recent SARS and swine flu epidemics. Using SARS as an example, we determined the effectiveness of infection control measures (ICMs) by logistic regression and structural equation modelling (SEM), a quantitative methodology that can test a hypothetical model and validates causal relationships among ICMs. Logistic regression showed that installing hand wash stations in the emergency room (p = 0.012, odds ratio = 1.07) was the only ICM significantly associated with the protection of HCWs from acquiring the SARS virus. The structural equation modelling results showed that the most important contributing factor (highest proportion of effectiveness) was installation of a fever screening station outside the emergency department (51%). Other measures included traffic control in the emergency department (19%), availability of an outbreak standard operation protocol (12%), mandatory temperature screening (9%), establishing a hand washing setup at each hospital checkpoint (3%), adding simplified isolation rooms (3%), and a standardized patient transfer protocol (3%). Installation of fever screening stations outside of the hospital and implementing traffic control in the emergency department contributed to 70% of the effectiveness in the prevention of SARS transmission. Our approach can be applied to the evaluation of control measures for other epidemic infectious diseases, including swine flu and avian flu.

Experimental Results of LightSAR Mision Planning Using a Market-Based System

NASA Technical Reports Server (NTRS)

Wessen, R.; Porter, D.; Hilland, J.

1999-01-01

The allocation of scarce spacecraft resources to multiple users has always been a difficult process. This difficulty arises from the fact that there are never enough resources to meet the stated requirements of the scientific investigators who compete to acquire their desired data sets.

Spaceborne synthetic aperture radar signal processing using FPGAs

NASA Astrophysics Data System (ADS)

Sugimoto, Yohei; Ozawa, Satoru; Inaba, Noriyasu

2017-10-01

Synthetic Aperture Radar (SAR) imagery requires image reproduction through successive signal processing of received data before browsing images and extracting information. The received signal data records of the ALOS-2/PALSAR-2 are stored in the onboard mission data storage and transmitted to the ground. In order to compensate the storage usage and the capacity of transmission data through the mission date communication networks, the operation duty of the PALSAR-2 is limited. This balance strongly relies on the network availability. The observation operations of the present spaceborne SAR systems are rigorously planned by simulating the mission data balance, given conflicting user demands. This problem should be solved such that we do not have to compromise the operations and the potential of the next-generation spaceborne SAR systems. One of the solutions is to compress the SAR data through onboard image reproduction and information extraction from the reproduced images. This is also beneficial for fast delivery of information products and event-driven observations by constellation. The Emergence Studio (Sōhatsu kōbō in Japanese) with Japan Aerospace Exploration Agency is developing evaluation models of FPGA-based signal processing system for onboard SAR image reproduction. The model, namely, "Fast L1 Processor (FLIP)" developed in 2016 can reproduce a 10m-resolution single look complex image (Level 1.1) from ALOS/PALSAR raw signal data (Level 1.0). The processing speed of the FLIP at 200 MHz results in twice faster than CPU-based computing at 3.7 GHz. The image processed by the FLIP is no way inferior to the image processed with 32-bit computing in MATLAB.

The Advanced Rapid Imaging and Analysis (ARIA) Project: Providing Standard and On-Demand SAR products for Hazard Science and Hazard Response

NASA Astrophysics Data System (ADS)

Owen, S. E.; Hua, H.; Rosen, P. A.; Agram, P. S.; Webb, F.; Simons, M.; Yun, S. H.; Sacco, G. F.; Liu, Z.; Fielding, E. J.; Lundgren, P.; Moore, A. W.

2017-12-01

A new era of geodetic imaging arrived with the launch of the ESA Sentinel-1A/B satellites in 2014 and 2016, and with the 2016 confirmation of the NISAR mission, planned for launch in 2021. These missions assure high quality, freely and openly distributed regularly sampled SAR data into the indefinite future. These unprecedented data sets are a watershed for solid earth sciences as we progress towards the goal of ubiquitous InSAR measurements. We now face the challenge of how to best address the massive volumes of data and intensive processing requirements. Should scientists individually process the same data independently themselves? Should a centralized service provider create standard products that all can use? Are there other approaches to accelerate science that are cost effective and efficient? The Advanced Rapid Imaging and Analysis (ARIA) project, a joint venture co-sponsored by California Institute of Technology (Caltech) and by NASA through the Jet Propulsion Laboratory (JPL), is focused on rapidly generating higher level geodetic imaging products and placing them in the hands of the solid earth science and local, national, and international natural hazard communities by providing science product generation, exploration, and delivery capabilities at an operational level. However, there are challenges in defining the optimal InSAR data products for the solid earth science community. In this presentation, we will present our experience with InSAR users, our lessons learned the advantages of on demand and standard products, and our proposal for the most effective path forward.

CryoSat-2: From SAR to LRM (FBR) for quantitative precision comparison over identical sea state

NASA Astrophysics Data System (ADS)

Martin-Puig, Cristina; Ruffini, Giulio; Raney, R. Keith; Gommenginger, Christine

The use of Synthetic Aperture Radar (SAR) techniques in conventional altimetry—i.e., Delay Doppler Altimetry (DDA)—was first introduced by R.K. Raney in 1998 [1]. This technique provides an improved solution for water surface altimetry observations due to two major innova-tions: the addition of along track processing for increased resolution, and multi-look processing for improved SNR. Cryosat-2 (scheduled for launch 2010) will be the first satellite to operate a SAR altimetry mode. Although its main focus will be the cryosphere, this instrument will also be sporadically operative over water surfaces, thus provide an opportunity to test and refine the improved capabilities of DDA. Moreover, the work presented here is of interest to the ESA's Sentinel-3 mission. This mission will be devoted to the provision of operational oceanographic services within Global Monitoring for the Environment and Security (GMES), and will include a DDA altimeter on board. SAMOSA, an ESA funded project, has studied along the last two years the potentialities of advanced DDA over water surfaces. Its extension aims to better quantify the improvement of DDA over conventional altimetry for the characterization of water surfaces. Cryosat-2s altimeter (SIRAL) has three operating modes: the Low Resolution Mode (LRM), the SAR mode and the inSAR mode. The first two are of interest for the work to be done. In LRM the altimeter performs as a conventional pulse limited altimeter (PRF of 1970 Hz); in SAR mode the pulses are transmitted in bursts (64 pulses per burst). In the last, correlation between echoes is desired [1], thus the PRF within a burst is higher than in LRM (PRF of 17.8 KHz). After transmission the altimeter waits for the returns, and transmits the next burst (burst repetition frequency of 85.7 Hz). The previous acquisition modes will provide different data products: level 1 or full bit rate data (FBR), level 1b or multi-looked waveform data, and level 2 for evaluation or geophysical products. This paper is only addressing FBR data for LRM and SAR mode. In LRM the FBR data corresponds to echoes incoherently multi-looked on-board the satellite at a rate of 20Hz, while in SAR mode FBR corresponds to individual complex echoes (I and Q), telemetered before the IFFT block [2]. Given that CryoSat-2 operational modes are exclusive, one task within SAMOSA extension aims to reduce SAR FBR data such that it emulates LRM FBR data allowing for the quantitative comparison of the measurement precision over identical sea state. In working to this aim, three methodolo-gies were implemented in the SAMOSA contract, the results achieved and detailed discussions with JHU/APL identified a revised approach (to be implemented in the SAMOSA extension), which should allow the team to meet the task goal. The different approaches will be presented in this paper. ACKNOWLEDGEMENT The authors of this paper would like to acknowledge the European Space Agency for funding the work presented in this paper, with special attention to J. Benveniste and S. Dinardo (ESA); and the SAMOSA team: D. Cotton (SatOC; UK), L. Stenseng (DTU; DE) and P. Berry (DMU; UK) REFERENCES [1] R.K.Raney, The Delay/Doppler Radar Altimeter, IEEE Trans. Georsci. Remote Sensing, vol. 36, pp. 1578-1588, Sep 1998. [2] CryoSat Mission and Data Description, Doc No. CS-RP-ESA-SY-0059, 2007.

Shuttle Radar Topography Mission (SRTM) Flight System Design and Operations Overview

NASA Technical Reports Server (NTRS)

Shen, Yuhsyen; Shaffer, Scott J.; Jordan, Rolando L.

2000-01-01

This paper provides an overview of the Shuttle Radar Topography Mission (SRTM), with emphasis on flight system implementation and mission operations from systems engineering perspective. Successfully flown in February, 2000, the SRTM's primary payload consists of several subsystems to form the first spaceborne dual-frequency (C-band and X-band) fixed baseline interferometric synthetic aperture radar (InSAR) system, with the mission objective to acquire data sets over 80% of Earth's landmass for height reconstruction. The paper provides system architecture, unique design features, engineering budgets, design verification, in-flight checkout and data acquisition of the SRTM payload, in particular for the C-band system. Mission operation and post-mission data processing activities are also presented. The complexity of the SRTM as a system, the ambitious mission objective, the demanding requirements and the high interdependency between multi-disciplined subsystems posed many challenges. The engineering experience and the insight thus gained have important implications for future spaceborne interferometric SAR mission design and implementation.

Multiscale Issues and Simulation-Based Science and Engineering for Materials-by-Design

DTIC Science & Technology

2010-05-15

planning and execution of programs to achieve the vision of ? material -by-design?. A key part of this effort has been to examine modeling at the mesoscale...15. SUBJECT TERMS Modelling & Simulation, Materials Design 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18...planning and execution of programs to achieve the vision of “ material -by-design”. A key part of this effort has been to examine modeling at the mesoscale. A

Digital Intermediate Frequency Receiver Module For Use In Airborne Sar Applications

DOEpatents

Tise, Bertice L.; Dubbert, Dale F.

2005-03-08

A digital IF receiver (DRX) module directly compatible with advanced radar systems such as synthetic aperture radar (SAR) systems. The DRX can combine a 1 G-Sample/sec 8-bit ADC with high-speed digital signal processor, such as high gate-count FPGA technology or ASICs to realize a wideband IF receiver. DSP operations implemented in the DRX can include quadrature demodulation and multi-rate, variable-bandwidth IF filtering. Pulse-to-pulse (Doppler domain) filtering can also be implemented in the form of a presummer (accumulator) and an azimuth prefilter. An out of band noise source can be employed to provide a dither signal to the ADC, and later be removed by digital signal processing. Both the range and Doppler domain filtering operations can be implemented using a unique pane architecture which allows on-the-fly selection of the filter decimation factor, and hence, the filter bandwidth. The DRX module can include a standard VME-64 interface for control, status, and programming. An interface can provide phase history data to the real-time image formation processors. A third front-panel data port (FPDP) interface can send wide bandwidth, raw phase histories to a real-time phase history recorder for ground processing.

Gulf Coast Subsidence: Integration of Geodesy, Geophysical Modeling, and Interferometric Synthetic Aperture Radar Observations

NASA Astrophysics Data System (ADS)

Blom, R. G.; Chapman, B. D.; Deese, R.; Dokka, R. K.; Fielding, E. J.; Hawkins, B.; Hensley, S.; Ivins, E. R.; Jones, C. E.; Kent, J. D.; Liu, Z.; Lohman, R.; Zheng, Y.

2012-12-01

The vulnerability of the US Gulf Coast has received increased attention in the years since hurricanes Katrina and Rita. Agencies responsible for the long-term protection of lives and infrastructure require precise estimates of future subsidence and sea level rise. A quantitative, geophysically based methodology can provide such estimates by incorporating geological data, geodetic measurements, geophysical models of non-elastic mechanical behavior at depth, and geographically comprehensive deformation monitoring made possible with measurements from Interferometric Synthetic Aperture Radar (InSAR). To be effective, results must be available to user agencies in a format suitable for integration within existing decision-support processes. Work to date has included analysis of historical and continuing ground-based geodetic measurements. These reveal a surprising degree of complexity, including regions that are subsiding at rates faster than those considered for hurricane protection planning of New Orleans and other coastal communities (http://www.mvn.usace.army.mil/pdf/hps_verticalsettlement.pdf) as well as Louisiana's coastal restoration strategies (http://www.coast2050.gov/2050reports.htm) (Dokka, 2011, J. Geophys. Res., 116, B06403, doi:10.1029/2010JB008008). Traditional geodetic measurements provide precise information at single points, while InSAR observations provide geographically comprehensive measurements of surface deformation at lower vertical precision. Available InSAR data sources include X-, C- and L-band satellite, and NASA/JPL airborne UAVSAR L-band data. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. For example, the shorter wavelength C-band data decorrelates over short time periods requiring more elaborate time-series analysis techniques, with which we've had some success. Meanwhile, preliminary analysis of limited L-Band ALOS/PALSAR satellite data show promise; unfortunately this Japanese satellite system failed in April 2011. We now have multiple airborne UAVSAR repeat pass interferometry data sets under analysis (http://uavsar.jpl.nasa.gov/) . UAVSAR interferogram processing has proven problematic in this environment, and new acquisitions are planned at shorter temporal intervals to yield improved results. Combining the geodetic and InSAR data can constrain geophysical models of crustal behavior, leading to quantitative predictions of future subsidence. Model results to date show good agreement between geodetic measurements and geophysically reasonable parameters including sediment load and ~130 m post-glacial sea level rise. We review work to date and present newly acquired UAVSAR data.

Near Real Time Applications for Maritime Situational Awareness

NASA Astrophysics Data System (ADS)

Schwarz, E.; Krause, D.; Berg, M.; Daedelow, H.; Maass, H.

2015-04-01

Applications to derive maritime value added products like oil spill and ship detection based on remote sensing SAR image data are being developed and integrated at the Ground Station Neustrelitz, part of the German Remote Sensing Data Center. Products of meteo-marine parameters like wind and wave will complement the product portfolio. Research and development aim at the implementation of highly automated services for operational use. SAR images are being used because of the possibility to provide maritime products with high spatial resolution over wide swaths and under all weather conditions. In combination with other information like Automatic Identification System (AIS) data fusion products are available to support the Maritime Situational Awareness.

Landslide Phenomena in Sevan National Park-Armenia

NASA Astrophysics Data System (ADS)

Lazarov, Dimitrov; Minchev, Dimitar; Aleksanyan, Gurgen; Ilieva, Maya

2010-12-01

Based on data from master and slave complex images obtained on 30 August 2008 and 4 October 2008 by satellite ENVISAT with ASAR sensor,all processing chain is performed to evaluate landslides phenomena in Sevan National park - Republic of Armenia. For this purpose Identification Deformation Inspection and Observation Tool developed by Berlin University of Technology is applied. This software package uses a freely available DEM of the Shuttle Radar Topography Mission (SRTM) and performs a fully automatic generation of differential SAR interferograms from ENVISAT single look complex SAR data. All interferometric processing steps are implemented with maximum quality and precision. The results illustrate almost calm Earth surface in the area of Sevan Lake.

The observation of ocean surface phenomena using imagery from the SEASAT synthetic aperture radar: An assessment

NASA Astrophysics Data System (ADS)

Vesecky, John F.; Stewart, Robert H.

1982-04-01

Over the period July 4 to October 10, 1978, the SEASAT synthetic aperture radar (SAR) gathered 23 cm wavelength radar images of some 108 km2 of the earth's surface, mainly of ocean areas, at 25-40 m resolution. Our assessment is in terms of oceanographic and ocean monitoring objectives and is directed toward discovering the proper role of SAR imagery in these areas of interest. In general, SAR appears to have two major and somewhat overlapping roles: first, quantitative measurement of ocean phenomena, like long gravity waves and wind fields, as well as measurement of ships; second, exploratory observations of large-scale ocean phenomena, such as the Gulf Stream and its eddies, internal waves, and ocean fronts. These roles are greatly enhanced by the ability of 23 cm SAR to operate day or night and through clouds. To begin we review some basics of synthetic aperture radar and its implementation on the SEASAT spacecraft. SEASAT SAR imagery of the ocean is fundamentally a map of the radar scattering characteristics of ˜30 cm wavelength ocean waves, distorted in some cases by ocean surface motion. We discuss how wind stress, surface currents, long gravity waves, and surface films modulate the scattering properties of these resonant waves with particular emphasis on the mechanisms that could produce images of long gravity waves. Doppler effects by ocean motion are also briefly described. Measurements of long (wavelength ≳100 m) gravity waves, using SEASAT SAR imagery, are compared with surface measurements during several experiments. Combining these results we find that dominant wavelength and direction are measured by SEASAT SAR within ±12% and ±15°, respectively. However, we note that ocean waves are not always visible in SAR images and discuss detection criteria in terms of wave height, length, and direction. SAR estimates of omnidirectional wave height spectra made by assuming that SAR image intensity is proportional to surface height fluctuations are more similar to corresponding surface measurements of wave height spectra than to wave slope spectra. Because SEASAT SAR images show the radar cross section σ° of ˜30 cm waves (neglecting doppler effects), and because these waves are raised by wind stress on the ocean surface, wind measurements are possible. Comparison between wind speeds estimated from SEASAT SAR imagery and from the SEASAT satellite scatterometer (SASS) agreed to within ±0.7 m s- over a 350-km comparison track and for wind speeds from 2 to 15 m s-. The great potential of SAR wind measurements lies in studying the spatial structure of the wind field over a range of spatial scales of from ≲1 km to ≳100 km. At present, the spatial and temporal structure of ocean wind fields is largely unknown. Because SAR responds to short waves whose energy density is a function of wind stress at the surface rather than wind speed at some distance above the surface, variations in image intensity may also reflect changes in air-sea temperature difference (thus complicating wind measurements by SAR). Because SAR images show the effects of surface current shear, air-sea temperature difference, and surface films through their modulation of the ˜30 cm waves, SEASAT images can be used to locate and study the Gulf Stream and related warm water rings, tidal flows at inlets, internal waves, and slicks resulting from surface films. In many of these applications, SAR provides a remote sensing capability that is complementary to infrared imagery because the two techniques sense largely different properties, namely, surface roughness and temperature. Both stationary ships and moving ships with their attendant wakes are often seen in SAR images. Ship images can be used to estimate ship size, heading, and speed. However, ships known to be in areas imaged by SAR are not always detectable. Clearly, a variety of factors, such as image resolution, ship size, sea state, and winds could affect ship detection. Overall, the role of SAR imagery in oceanography is definitely evolving at this time, but its ultimate role is unclear. We have assessed the ability of SEASAT SAR to measure a variety of ocean phenomena and have commented briefly on applications. In the end, oceanographers and others will have to judge from these capabilities the proper place for SAR in oceanography and remote sensing of the ocean.

An oceanographic survey for oil spill monitoring and model forecasting validation using remote sensing and in situ data in the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Pisano, A.; De Dominicis, M.; Biamino, W.; Bignami, F.; Gherardi, S.; Colao, F.; Coppini, G.; Marullo, S.; Sprovieri, M.; Trivero, P.; Zambianchi, E.; Santoleri, R.

2016-11-01

A research cruise was organized on board the Italian National Research Council (CNR) R/V Urania to test the oil spill monitoring system developed during the PRogetto pilota Inquinamento Marino da Idrocarburi project (PRIMI, pilot project for marine oil pollution). For the first time, this system integrated in a modular way satellite oil spill detection (Observation Module) and oil spill displacement forecasting (Forecast Module) after detection. The Observation Module was based on both Synthetic Aperture RADAR (SAR) and optical satellite detection, namely SAR and Optical Modules, while the Forecast Module on Lagrangian numerical circulation models. The cruise (Aug. 6-Sep. 7, 2009) took place in the Mediterranean Sea, around Sicily, an area affected by heavy oil tanker traffic with frequent occurrence of oil spills resulting from illegal tank washing. The cruise plan was organized in order to have the ship within the SAR image frames selected for the cruise, at acquisition time. In this way, the ship could rapidly reach oil slicks detected in the images by the SAR Module, and/or eventually by the Optical Module, in order to carry out visual and instrumental inspection of the slicks. During the cruise, several oil spills were detected by the two Observation Modules and verified in situ, with the essential aid of the Forecasting Module which provided the slick position by the time the ship reached the area after the alert given by the SAR and/or optical imagery. Results confirm the good capability of oil spill SAR detection and indicate that also optical sensors are able to detect oil spills, ranging from thin films to slicks containing heavily polluted water. Also, results confirm the useful potential of oil spill forecasting models, but, on the other hand, that further work combining satellite, model and in situ data is necessary to refine the PRIMI system.

Internal Wave Study in the South China Sea Using SAR

NASA Technical Reports Server (NTRS)

Liu, Antony K.; Hsu, Ming-Kuang; Zukor, Dorothy (Technical Monitor)

2000-01-01

Recently, the internal wave distribution maps in the China Seas have been compiled from hundreds of ERS-1/2, RADARSAT, and Space Shuttle SAR (Synthetic Aperture Radar) images from 1993 to 1999. Based on internal wave distribution map, most of internal waves in the northeast part of South China Sea were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m due to strong current from the Kuroshio branching out into the South China Sea. Based on the observations from drilling rigs near DongSha Island by Amoco Production Co., the solitons may be generated in a 4 km wide channel between Batan and Sabtang islands in Luzon Strait. The proposed generation mechanism is similar to the lee wave formation from a shallow topography. Both depression and elevation internal waves have been observed in the same RADARSAT ScanSAR image on May 4, 1998 near DongSha Island. Furthermore, depression and elevation internal waves have also been observed by SAR at the same location on the shelf in April and June, 1993 (in different seasons) respectively. Numerical models have been used to interpret their generation mechanism and evolution processes. Based on the SAR images, near DongSha Island, the westward propagating huge internal solitons are often encountered and diffracted/broken by the coral reefs on the shelf. After passing the island, the diffracted waves will re-merge or interact with each other. It has been observed that after the nonlinear wave-wave interaction, the phase of wave packet is shifted and wavelength is also changed. Examples of mesoscale features observed in SAR images, such as fronts, raincells, bathymetry, ship wakes, and oil spills will be presented. Recent mooring measurements in April 1999 near Dongsha Island, future field test ASIAEX (Asian Seas International Acoustics Experiment) planned for April 2001, and some pretest survey data will be discussed in this paper.

Transmission dynamics of Ebola virus disease and intervention effectiveness in Sierra Leone

PubMed Central

Fang, Li-Qun; Yang, Yang; Jiang, Jia-Fu; Yao, Hong-Wu; Kargbo, David; Li, Xin-Lou; Jiang, Bao-Gui; Kargbo, Brima; Tong, Yi-Gang; Wang, Ya-Wei; Liu, Kun; Kamara, Abdul; Dafae, Foday; Kanu, Alex; Jiang, Rui-Ruo; Sun, Ye; Sun, Ruo-Xi; Chen, Wan-Jun; Ma, Mai-Juan; Dean, Natalie E.; Thomas, Harold; Longini, Ira M.; Halloran, M. Elizabeth; Cao, Wu-Chun

2016-01-01

Sierra Leone is the most severely affected country by an unprecedented outbreak of Ebola virus disease (EVD) in West Africa. Although successfully contained, the transmission dynamics of EVD and the impact of interventions in the country remain unclear. We established a database of confirmed and suspected EVD cases from May 2014 to September 2015 in Sierra Leone and mapped the spatiotemporal distribution of cases at the chiefdom level. A Poisson transmission model revealed that the transmissibility at the chiefdom level, estimated as the average number of secondary infections caused by a patient per week, was reduced by 43% [95% confidence interval (CI): 30%, 52%] after October 2014, when the strategic plan of the United Nations Mission for Emergency Ebola Response was initiated, and by 65% (95% CI: 57%, 71%) after the end of December 2014, when 100% case isolation and safe burials were essentially achieved, both compared with before October 2014. Population density, proximity to Ebola treatment centers, cropland coverage, and atmospheric temperature were associated with EVD transmission. The household secondary attack rate (SAR) was estimated to be 0.059 (95% CI: 0.050, 0.070) for the overall outbreak. The household SAR was reduced by 82%, from 0.093 to 0.017, after the nationwide campaign to achieve 100% case isolation and safe burials had been conducted. This study provides a complete overview of the transmission dynamics of the 2014−2015 EVD outbreak in Sierra Leone at both chiefdom and household levels. The interventions implemented in Sierra Leone seem effective in containing the epidemic, particularly in interrupting household transmission. PMID:27035948

Science plan for the Alaska SAR facility program. Phase 1: Data from the first European sensing satellite, ERS-1

NASA Technical Reports Server (NTRS)

Carsey, Frank D.

1989-01-01

Science objectives, opportunities and requirements are discussed for the utilization of data from the Synthetic Aperture Radar (SAR) on the European First Remote Sensing Satellite, to be flown by the European Space Agency in the early 1990s. The principal applications of the imaging data are in studies of geophysical processes taking place within the direct-reception area of the Alaska SAR Facility in Fairbanks, Alaska, essentially the area within 2000 km of the receiver. The primary research that will be supported by these data include studies of the oceanography and sea ice phenomena of Alaskan and adjacent polar waters and the geology, glaciology, hydrology, and ecology of the region. These studies focus on the area within the reception mask of ASF, and numerous connections are made to global processes and thus to the observation and understanding of global change. Processes within the station reception area both affect and are affected by global phenomena, in some cases quite critically. Requirements for data processing and archiving systems, prelaunch research, and image processing for geophysical product generation are discussed.

Surface Current Skill Assessment of Global and Regional forecast models.

NASA Astrophysics Data System (ADS)

Allen, A. A.

2016-02-01

The U.S. Coast Guard has been using SAROPS since January 2007 at all fifty of its operational centers to plan search and rescue missions. SAROPS relies on an Environmental Data Server (EDS) that integrates global, national, and regional ocean and meteorological observation and forecast data. The server manages spatial and temporal aggregation of hindcast, nowcast, and forecast data so the SAROPS controller has the best available data for search planning. The EDS harvests a wide range of global and regional forecasts and data, including NOAA NCEP's global HYCOM model (RTOFS), the U.S. Navy's Global HYCOM model, the 5 NOAA NOS Great Lakes models and a suite of other reginal forecasts from NOS and IOOS Regional Associations. The EDS also integrates surface drifter data as the U.S. Coast Guard regularly deploys Self-Locating Datum Marker Buoys (SLDMBs) during SAR cases and a significant set of drifter data has been collected and the archive continues to grow. This data is critically useful during real-time SAR planning, but also represents a valuable scientific dataset for analyzing surface currents. In 2014, a new initiative was started by the U.S. Coast Guard to evaluate the skill of the various models to support the decision making process during search and rescue planning. This analysis falls into 2 categories: historical analysis of drifter tracks and model predictions to provide skill assessment of models in different regions and real-time analysis of models and drifter tracks during a SAR incident. The EDS, using Liu and Wiesberg's (2014) autonomously determines surface skill measurements of the co-located models' simulated surface trajectories versus the actual drift of the SLDMBs (CODE/Davis style surface drifters GPS positioned at 30min intervals). Surface skill measurements are archived in a database and are user retrieval by lat/long/time cubes. This paper will focus on the comparison of models from in the period from 23 August to 21 September 2015. Surface Skill was determined for the following regions: California Coast, Gulf of Mexico, South and Mid Atlantic Bights. Skill was determined for the two version of the NCEP Global RTOFS, Navy's Global HYCOM model, and where appropriated the local regional models

The impact of ERI, burnout, and caring for SARS patients on hospital nurses' self-reported compliance with infection control.

PubMed

Pratt, Maria; Kerr, Michael; Wong, Carol

2009-01-01

Siegrist's (1996) Effort-Reward Imbalance (ERI) Model provided the theoretical basis for this secondary data analysis that examines the relationship between nurses' ERI and their self-reported compliance with infection control, between ERI and burnout and nurses' compliance, and between nurses' experience in caring for SARS patients and their compliance with infection control. Data for this study came from a collaborative interdisciplinary study examining the barriers and facilitators to implementing protective measures against SARS and other existing and emerging infections among hospital nurses in Ontario and British Columbia. This is the first study to examine the relationship between ERI and compliance with infection control, as well as the impact of nurses' experience in caring for SARS patients on their compliance behaviour with infection control. Hierarchical multiple linear regression analyses revealed that ERI is a significant predictor of decreased compliance with infection control (beta = -.15, p < .05). While ERI was shown to be associated with burnout (beta = .60, p < .001), the combined effect of these two variables did not significantly improve the prediction of compliance behaviour (beta = -.03, p = .63). Nurses who reported having directly cared for SARS patients were found to have increased compliance with infection control (beta = .15, p < .001) after controlling for demographic and work environment factors. These findings highlight how nurses' adverse workplace environments can affect their work and health and thus, can be used by nursing and hospital administrators to help develop interventions to lower occupational stress and improve health in the workplace.

Flood Inundation Mapping and Management using RISAT-1 derived Flood Inundation Areas, Cartosat-1 DEM and a River Flow Model

NASA Astrophysics Data System (ADS)

Kuldeep, K.; Garg, P. K.; Garg, R. D.

2017-12-01

The frequent occurrence of repeated flood events in many regions of the world causing damage to human life and property has augmented the need for effective flood risk management. Microwave satellite data is becoming an indispensable asset for monitoring of many environmental and climatic applications as numerous space-borne synthetic aperture radar (SAR) sensors are offering the data with high spatial resolutions and multi-polarization capabilities. The implementation and execution of Flood mapping, monitoring and management applications has become easier with the availability of SAR data which has obvious advantages over optical data due to its all weather, day and night capabilities. In this study, the exploitation of the SAR dataset for hydraulic modelling and disaster management has been highlighted using feature extraction techniques for water area identification and water level extraction within the floodplain. The availability of high precision digital elevation model generated from the Cartosat-1 stereo pairs has enhanced the capability of retrieving the water depth maps by incorporating the SAR derived flood extent maps. This paper illustrates the flood event on June 2013 in Yamuna River, Haryana, India. The water surface profile computed by combining the topographic data with the RISAT-1 data accurately reflects the true water line. Water levels that were computed by carrying out the modelling using hydraulic model in HECRAS also suggest that the water surface profiles provided by the combined use of topographic data and SAR accurately reflect the true water line. The proposed approach has also been found better in extraction of inundation within vegetated areas.

Post-Disaster Damage Assessment Through Coherent Change Detection on SAR Imagery

NASA Astrophysics Data System (ADS)

Guida, L.; Boccardo, P.; Donevski, I.; Lo Schiavo, L.; Molinari, M. E.; Monti-Guarnieri, A.; Oxoli, D.; Brovelli, M. A.

2018-04-01

Damage assessment is a fundamental step to support emergency response and recovery activities in a post-earthquake scenario. In recent years, UAVs and satellite optical imagery was applied to assess major structural damages before technicians could reach the areas affected by the earthquake. However, bad weather conditions may harm the quality of these optical assessments, thus limiting the practical applicability of these techniques. In this paper, the application of Synthetic Aperture Radar (SAR) imagery is investigated and a novel approach to SAR-based damage assessment is presented. Coherent Change Detection (CCD) algorithms on multiple interferometrically pre-processed SAR images of the area affected by the seismic event are exploited to automatically detect potential damages to buildings and other physical structures. As a case study, the 2016 Central Italy earthquake involving the cities of Amatrice and Accumoli was selected. The main contribution of the research outlined above is the integration of a complex process, requiring the coordination of a variety of methods and tools, into a unitary framework, which allows end-to-end application of the approach from SAR data pre-processing to result visualization in a Geographic Information System (GIS). A prototype of this pipeline was implemented, and the outcomes of this methodology were validated through an extended comparison with traditional damage assessment maps, created through photo-interpretation of high resolution aerial imagery. The results indicate that the proposed methodology is able to perform damage detection with a good level of accuracy, as most of the detected points of change are concentrated around highly damaged buildings.

A new automatic SAR-based flood mapping application hosted on the European Space Agency's grid processing on demand fast access to imagery environment

NASA Astrophysics Data System (ADS)

Hostache, Renaud; Chini, Marco; Matgen, Patrick; Giustarini, Laura

2013-04-01

There is a clear need for developing innovative processing chains based on earth observation (EO) data to generate products supporting emergency response and flood management at a global scale. Here an automatic flood mapping application is introduced. The latter is currently hosted on the Grid Processing on Demand (G-POD) Fast Access to Imagery (Faire) environment of the European Space Agency. The main objective of the online application is to deliver flooded areas using both recent and historical acquisitions of SAR data in an operational framework. It is worth mentioning that the method can be applied to both medium and high resolution SAR images. The flood mapping application consists of two main blocks: 1) A set of query tools for selecting the "crisis image" and the optimal corresponding pre-flood "reference image" from the G-POD archive. 2) An algorithm for extracting flooded areas using the previously selected "crisis image" and "reference image". The proposed method is a hybrid methodology, which combines histogram thresholding, region growing and change detection as an approach enabling the automatic, objective and reliable flood extent extraction from SAR images. The method is based on the calibration of a statistical distribution of "open water" backscatter values inferred from SAR images of floods. Change detection with respect to a pre-flood reference image helps reducing over-detection of inundated areas. The algorithms are computationally efficient and operate with minimum data requirements, considering as input data a flood image and a reference image. Stakeholders in flood management and service providers are able to log onto the flood mapping application to get support for the retrieval, from the rolling archive, of the most appropriate pre-flood reference image. Potential users will also be able to apply the implemented flood delineation algorithm. Case studies of several recent high magnitude flooding events (e.g. July 2007 Severn River flood, UK and March 2010 Red River flood, US) observed by high-resolution SAR sensors as well as airborne photography highlight advantages and limitations of the online application. A mid-term target is the exploitation of ESA SENTINEL 1 SAR data streams. In the long term it is foreseen to develop a potential extension of the application for systematically extracting flooded areas from all SAR images acquired on a daily, weekly or monthly basis. On-going research activities investigate the usefulness of the method for mapping flood hazard at global scale using databases of historic SAR remote sensing-derived flood inundation maps.

Calibrating a hydraulic model using water levels derived from time series high-resolution Radarsat-2 synthetic aperture radar images and elevation data

NASA Astrophysics Data System (ADS)

Trudel, M.; Desrochers, N.; Leconte, R.

2017-12-01

Knowledge of water extent (WE) and level (WL) of rivers is necessary to calibrate and validate hydraulic models and thus to better simulate and forecast floods. Synthetic aperture radar (SAR) has demonstrated its potential for delineating water bodies, as backscattering of water is much lower than that of other natural surfaces. The ability of SAR to obtain information despite cloud cover makes it an interesting tool for temporal monitoring of water bodies. The delineation of WE combined with a high-resolution digital terrain model (DTM) allows extracting WL. However, most research using SAR data to calibrate hydraulic models has been carried out using one or two images. The objectives of this study is to use WL derived from time series high resolution Radarsat-2 SAR images for the calibration of a 1-D hydraulic model (HEC-RAS). Twenty high-resolution (5 m) Radarsat-2 images were acquired over a 40 km reach of the Athabasca River, in northern Alberta, Canada, between 2012 and 2016, covering both low and high flow regimes. A high-resolution (2m) DTM was generated combining information from LIDAR data and bathymetry acquired between 2008 and 2016 by boat surveying. The HEC-RAS model was implemented on the Athabasca River to simulate WL using cross-sections spaced by 100 m. An image histogram thresholding method was applied on each Radarsat-2 image to derive WE. WE were then compared against each cross-section to identify those were the slope of the banks is not too abrupt and therefore amenable to extract WL. 139 observations of WL at different locations along the river reach and with streamflow measurements were used to calibrate the HEC-RAS model. The RMSE between SAR-derived and simulated WL is under 0.35 m. Validation was performed using in situ observations of WL measured in 2008, 2012 and 2016. The RMSE between the simulated water levels calibrated with SAR images and in situ observations is less than 0.20 m. In addition, a critical success index (CSI) was performed to compare the WE simulated by HEC-RAS and that derived from SARs images. The CSI is higher than 0.85 for each date, which means that simulated WE is highly similar to the WE derived from SARs images. Thereby, the results of our analysis indicate that calibration of a hydraulic model can be performed from WL derived from time series of high-resolution SAR images.

Upper ocean fine-scale features in synthetic aperture radar imagery. Part I: Simultaneous satellite and in-situ measurements

NASA Astrophysics Data System (ADS)

Soloviev, A.; Maingot, C.; Matt, S.; Fenton, J.; Lehner, S.; Brusch, S.; Perrie, W. A.; Zhang, B.

2011-12-01

The new generation of synthetic aperture radar (SAR) satellites provides high resolution images that open new opportunities for identifying and studying fine features in the upper ocean. The problem is, however, that SAR images of the sea surface can be affected by atmospheric phenomena (rain cells, fronts, internal waves, etc.). Implementation of in-situ techniques in conjunction with SAR is instrumental for discerning the origin of features on the image. This work is aimed at the interpretation of natural and artificial features in SAR images. These features can include fresh water lenses, sharp frontal interfaces, internal wave signatures, as well as slicks of artificial and natural origin. We have conducted field experiments in the summer of 2008 and 2010 and in the spring of 2011 to collect in-situ measurements coordinated with overpasses of the TerraSAR-X, RADARSAT-2, ALOS PALSAR, and COSMO SkyMed satellites. The in-situ sensors deployed in the Straits of Florida included a vessel-mounted sonar and CTD system to record near-surface data on stratification and frontal boundaries, a bottom-mounted Nortek AWAC system to gather information on currents and directional wave spectra, an ADCP mooring at a 240 m isobath, and a meteorological station. A nearby NOAA NEXRAD Doppler radar station provided a record of rainfall in the area. Controlled releases of menhaden fish oil were performed from our vessel before several satellite overpasses in order to evaluate the effect of surface active materials on visibility of sea surface features in SAR imagery under different wind-wave conditions. We found evidence in the satellite images of rain cells, squall lines, internal waves of atmospheric and possibly oceanic origin, oceanic frontal interfaces and submesoscale eddies, as well as anthropogenic signatures of ships and their wakes, and near-shore surface slicks. The combination of satellite imagery and coordinated in-situ measurements was helpful in interpreting fine-scale features on the sea surface observed in the SAR images and, in some cases, linking them to thermohaline features in the upper ocean. Finally, we have been able to reproduce SAR signatures of freshwater plumes and sharp frontal interfaces interacting with wind stress, as well as internal waves by combining hydrodynamic simulations with a radar imaging algorithm. The modeling results are presented in a companion paper (Matt et al., 2011).

Experiment in Onboard Synthetic Aperture Radar Data Processing

NASA Technical Reports Server (NTRS)

Holland, Matthew

2011-01-01

Single event upsets (SEUs) are a threat to any computing system running on hardware that has not been physically radiation hardened. In addition to mandating the use of performance-limited, hardened heritage equipment, prior techniques for dealing with the SEU problem often involved hardware-based error detection and correction (EDAC). With limited computing resources, software- based EDAC, or any more elaborate recovery methods, were often not feasible. Synthetic aperture radars (SARs), when operated in the space environment, are interesting due to their relevance to NASAs objectives, but problematic in the sense of producing prodigious amounts of raw data. Prior implementations of the SAR data processing algorithm have been too slow, too computationally intensive, and require too much application memory for onboard execution to be a realistic option when using the type of heritage processing technology described above. This standard C-language implementation of SAR data processing is distributed over many cores of a Tilera Multicore Processor, and employs novel Radiation Hardening by Software (RHBS) techniques designed to protect the component processes (one per core) and their shared application memory from the sort of SEUs expected in the space environment. The source code includes calls to Tilera APIs, and a specialized Tilera compiler is required to produce a Tilera executable. The compiled application reads input data describing the position and orientation of a radar platform, as well as its radar-burst data, over time and writes out processed data in a form that is useful for analysis of the radar observations.

Application of InSAR to detection of localized subsidence and its effects on flood protection infrastructure in the New Orleans area

NASA Astrophysics Data System (ADS)

Jones, Cathleen; Blom, Ronald; Latini, Daniele

2014-05-01

The vulnerability of the United States Gulf of Mexico coast to inundation has received increasing attention in the years since hurricanes Katrina and Rita. Flood protection is a challenge throughout the area, but the population density and cumulative effect of historic subsidence makes it particularly difficult in the New Orleans area. Analysis of historical and continuing geodetic measurements identifies a surprising degree of complexity in subsidence (Dokka 2011), including regions that are subsiding at rates faster than those considered during planning for hurricane protection and for coastal restoration projects. Improved measurements are possible through combining traditional single point, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations for to obtain geographically dense constraints on surface deformation. The Gulf Coast environment is very challenging for InSAR techniques, especially with systems not designed for interferometry. We are applying pair-wise InSAR to longer wavelength (L-band, 24 cm) synthetic aperture radar data acquired with the airborne UAVSAR instrument (http://uavsar.jpl.nasa.gov/) to detect localized change impacting flood protection infrastructure in the New Orleans area during the period from 2009 - 2013. Because aircraft motion creates large-scale image artifacts across the scene, we focus on localized areas on and near flood protection infrastructure to identify anomalous change relative to the surrounding area indicative of subsidence, structural deformation, and/or seepage (Jones et al., 2011) to identify areas where problems exist. C-band and particularly X-band radar returns decorrelate over short time periods in rural or less urbanized areas and are more sensitive to atmospheric affects, necessitating more elaborate analysis techniques or, at least, a strict limit on the temporal baseline. The new generation of spaceborne X-band SAR acquisitions ensure relatively high frequency of acquisition, a dramatic increase of persistent scatter density in urban areas, and improved measurement of very small displacements (Crosetto et al., 2010). We compare the L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period, to determine the influence of different radar frequencies and analyses techniques. Our applications goal is to demonstrate a technique to inform targeted ground surveys, identify areas of persistent subsidence, and improve overall monitoring and planning in flood risk areas. Dokka, 2011, The role of deep processes in late 20th century subsidence of New Orleans and coastal areas of southern Louisiana and Mississippi: J. Geophys. Res., 116, B06403, doi:10.1029/2010JB008008. Jones, C. E., G. Bawden, S. Deverel, J. Dudas, S. Hensley, Study of movement and seepage along levees using DINSAR and the airborne UAVSAR instrument, Proc. SPIE 8536, SAR Image Analysis, Modeling, and Techniques XII, 85360E (November 21, 2012); doi:10.1117/12.976885. Crosetto, M., Monserrat, O., Iglesias, R., & Crippa, B. (2010). Persistent Scatterer Interferometry: Potential, limits and initial C-and X-band comparison. Photogrammetric engineering and remote sensing, 76(9), 1061-1069. Acknowledgments: This research was carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

Site-wide seismic risk model for Savannah River Site nuclear facilities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eide, S.A.; Shay, R.S.; Durant, W.S.

1993-09-01

The 200,000 acre Savannah River Site (SRS) has nearly 30 nuclear facilities spread throughout the site. The safety of each facility has been established in facility-specific safety analysis reports (SARs). Each SAR contains an analysis of risk from seismic events to both on-site workers and the off-site population. Both radiological and chemical releases are considered, and air and water pathways are modeled. Risks to the general public are generally characterized by evaluating exposure to the maximally exposed individual located at the SRS boundary and to the off-site population located within 50 miles. Although the SARs are appropriate methods for studyingmore » individual facility risks, there is a class of accident initiators that can simultaneously affect several of all of the facilities, Examples include seismic events, strong winds or tornados, floods, and loss of off-site electrical power. Overall risk to the off-site population from such initiators is not covered by the individual SARs. In such cases multiple facility radionuclide or chemical releases could occur, and off-site exposure would be greater than that indicated in a single facility SAR. As a step towards an overall site-wide risk model that adequately addresses multiple facility releases, a site-wide seismic model for determining off-site risk has been developed for nuclear facilities at the SRS. Risk from seismic events up to the design basis earthquake (DBE) of 0.2 g (frequency of 2.0E-4/yr) is covered by the model. Present plans include expanding the scope of the model to include other types of initiators that can simultaneously affect multiple facilities.« less

LiDAR data and SAR imagery acquired by an unmanned helicopter for rapid landslide investigation

NASA Astrophysics Data System (ADS)

Kasai, M.; Tanaka, Y.; Yamazaki, T.

2012-12-01

When earthquakes or heavy rainfall hits a landslide prone area, initial actions require estimation of the size of damage to people and infrastructure. This includes identifying the number and size of newly collapsed or expanded landslides, and appraising subsequent risks from remobilization of landslides and debris materials. In inapproachable areas, the UAV (Unmanned Aerial Vehicles) is likely to be of greatest use. In addition, repeat monitoring of sites after the event is a way of utilizing UAVs, particularly in terms of cost and convenience. In this study, LiDAR (SkEyesBox MP-1) data and SAR (Nano SAR) imagery, acquired over 0.5 km2 landslide prone area, are presented to assess the practicability of using unmanned helicopters (in this case a 10 year old YAMAHA RMAX G1) in these situations. LiDAR data was taken in July 2012, when tree foliage covered the ground surface. However, imagery was of sufficient quality to identify and measure landslide features. Nevertheless, LiDAR data obtained by a manned helicopter in the same area in August 2008 was more detailed, reflecting the function of the LiDAR scanner. On the other hand, 2 m resolution Nano SAR imagery produced reasonable results to elucidate hillslope condition. A quick method for data processing without loss of image quality was also investigated. In conclusion, the LiDAR scanner and UAV employed here could be used to plan immediate remedial activity of the area, before LiDAR measurement with a manned helicopter can be organized. SAR imagery from UAV is also available for this initial activity, and can be further applied to long term monitoring.

Basic to Advanced InSAR Processing: GMTSAR

NASA Astrophysics Data System (ADS)

Sandwell, D. T.; Xu, X.; Baker, S.; Hogrelius, A.; Mellors, R. J.; Tong, X.; Wei, M.; Wessel, P.

2017-12-01

Monitoring crustal deformation using InSAR is becoming a standard technique for the science and application communities. Optimal use of the new data streams from Sentinel-1 and NISAR will require open software tools as well as education on the strengths and limitations of the InSAR methods. Over the past decade we have developed freely available, open-source software for processing InSAR data. The software relies on the Generic Mapping Tools (GMT) for the back-end data analysis and display and is thus called GMTSAR. With startup funding from NSF, we accelerated the development of GMTSAR to include more satellite data sources and provide better integration and distribution with GMT. In addition, with support from UNAVCO we have offered 6 GMTSAR short courses to educate mostly novice InSAR users. Currently, the software is used by hundreds of scientists and engineers around the world to study deformation at more than 4300 different sites. The most challenging aspect of the recent software development was the transition from image alignment using the cross-correlation method to a completely new alignment algorithm that uses only the precise orbital information to geometrically align images to an accuracy of better than 7 cm. This development was needed to process a new data type that is being acquired by the Sentinel-1A/B satellites. This combination of software and open data is transforming radar interferometry from a research tool into a fully operational time series analysis tool. Over the next 5 years we are planning to continue to broaden the user base through: improved software delivery methods; code hardening; better integration with data archives; support for high level products being developed for NISAR; and continued education and outreach.

75 FR 75586 - Confidentiality of Suspicious Activity Reports

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-03

...] RIN 1550-AC26 Confidentiality of Suspicious Activity Reports AGENCY: The Office of Thrift Supervision... implementing the Bank Secrecy Act (BSA) governing the confidentiality of a suspicious activity report (SAR) to... corporations regulated by the OTS, to keep certain records and make certain reports that have been determined...

Radarsat Antarctic Mapping Project: Antarctic Imaging Campaign 2

NASA Technical Reports Server (NTRS)

2001-01-01

The Radarsat Antarctic Mapping Project is a collaboration between NASA and the Canadian Space Agency to map Antarctica using synthetic aperture radar (SAR). The first Antarctic Mapping Mission (AMM-1) was successfully completed in October 1997. Data from the acquisition phase of the 1997 campaign have been used to achieve the primary goal of producing the first, high-resolution SAR image map of Antarctica. The limited amount of data suitable for interferometric analysis have also been used to produce remarkably detailed maps of surface velocity for a few selected regions. Most importantly, the results from AMM-1 are now available to the general science community in the form of various resolution, radiometrically calibrated and geometrically accurate image mosaics. The second Antarctic imaging campaign occurred during the fall of 2000. Modified from AMM-1, the satellite remained in north looking mode during AMM-2 restricting coverage to regions north of about -80 degrees latitude. But AMM-2 utilized for the first time RADARSAT-1 fine beams providing an unprecedented opportunity to image many of Antarctica's fast glaciers whose extent was revealed through AMM-1 data. AMM-2 also captured extensive data suitable for interferometric analysis of the surface velocity field. This report summarizes the science goals, mission objectives, and project status through the acquisition phase and the start of the processing phase. The reports describes the efforts of team members including Alaska SAR Facility, Jet Propulsion Laboratory, Vexcel Corporation, Goddard Space Flight Center, Wallops Flight Facility, Ohio State University, Environmental Research Institute of Michigan, White Sands Facility, Canadian Space Agency Mission Planning and Operations Groups, and the Antarctic Mapping Planning Group.

A new automatic synthetic aperture radar-based flood mapping application hosted on the European Space Agency's Grid Processing of Demand Fast Access to Imagery environment

NASA Astrophysics Data System (ADS)

Matgen, Patrick; Giustarini, Laura; Hostache, Renaud

2012-10-01

This paper introduces an automatic flood mapping application that is hosted on the Grid Processing on Demand (GPOD) Fast Access to Imagery (Faire) environment of the European Space Agency. The main objective of the online application is to deliver operationally flooded areas using both recent and historical acquisitions of SAR data. Having as a short-term target the flooding-related exploitation of data generated by the upcoming ESA SENTINEL-1 SAR mission, the flood mapping application consists of two building blocks: i) a set of query tools for selecting the "crisis image" and the optimal corresponding "reference image" from the G-POD archive and ii) an algorithm for extracting flooded areas via change detection using the previously selected "crisis image" and "reference image". Stakeholders in flood management and service providers are able to log onto the flood mapping application to get support for the retrieval, from the rolling archive, of the most appropriate reference image. Potential users will also be able to apply the implemented flood delineation algorithm. The latter combines histogram thresholding, region growing and change detection as an approach enabling the automatic, objective and reliable flood extent extraction from SAR images. Both algorithms are computationally efficient and operate with minimum data requirements. The case study of the high magnitude flooding event that occurred in July 2007 on the Severn River, UK, and that was observed with a moderateresolution SAR sensor as well as airborne photography highlights the performance of the proposed online application. The flood mapping application on G-POD can be used sporadically, i.e. whenever a major flood event occurs and there is a demand for SAR-based flood extent maps. In the long term, a potential extension of the application could consist in systematically extracting flooded areas from all SAR images acquired on a daily, weekly or monthly basis.

Escapement and Productivity of Spring Chinook Salmon and Summer Steelhead in the John Day River Basin, 2005-2006 Annual Technical Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schultz, Terra Lang; Wilson, Wayne H.; Ruzycki, James R.

The objectives are: (1) Estimate number and distribution of spring Chinook salmon Oncorhynchus tshawytscha redds and spawners in the John Day River subbasin; and (2) Estimate smolt-to-adult survival rates (SAR) and out-migrant abundance for spring Chinook and summer steelhead O. mykiss and life history characteristics of summer steelhead. The John Day River subbasin supports one of the last remaining intact wild populations of spring Chinook salmon and summer steelhead in the Columbia River Basin. These populations, however, remain depressed relative to historic levels. Between the completion of the life history and natural escapement study in 1984 and the start ofmore » this project in 1998, spring Chinook spawning surveys did not provide adequate information to assess age structure, progeny-to-parent production values, smolt-to-adult survival (SAR), or natural spawning escapement. Further, only very limited information is available for steelhead life history, escapement, and productivity measures in the John Day subbasin. Numerous habitat protection and rehabilitation projects to improve salmonid freshwater production and survival have also been implemented in the basin and are in need of effectiveness monitoring. While our monitoring efforts outlined here will not specifically measure the effectiveness of any particular project, they will provide much needed background information for developing context for project-specific effectiveness monitoring efforts. To meet the data needs as index stocks, to assess the long-term effectiveness of habitat projects, and to differentiate freshwater and ocean survival, sufficient annual estimates of spawner escapement, age structure, SAR, egg-to-smolt survival, smolt-per-redd ratio, and freshwater habitat use are essential. We have begun to meet this need through spawning ground surveys initiated for spring Chinook salmon in 1998 and smolt PIT-tagging efforts initiated in 1999. Additional sampling and analyses to meet these goals include an estimate of smolt abundance and SAR rates, and an updated measure of the freshwater distribution of critical life stages. Because Columbia Basin managers have identified the John Day subbasin spring Chinook population as an index population for assessing the effects of alternative future management actions on salmon stocks in the Columbia Basin (Schaller et al. 1999) we continue our ongoing studies. This project is high priority based on the high level of emphasis the NWPPC Fish and Wildlife Program, Subbasin Summaries, NMFS, and the Oregon Plan for Salmon and Watersheds have placed on monitoring and evaluation to provide the real-time data to guide restoration and adaptive management in the region. By implementing the proposed program we have been able to address many of the goals for population status monitoring, such as defining areas currently used by spring Chinook for holding and spawning habitats and determining range expansion or contraction of summer rearing and spawning populations. The BiOp describes these goals as defining population growth rates (adult monitoring), detecting changes in those growth rates or relative abundance in a reasonable time (adult/juvenile monitoring), estimating juvenile abundance and survival rates (juvenile/smolt monitoring), and identifying stage-specific survival (adult-to-smolt, smolt-to-adult).« less

A SAR-ADC using unit bridge capacitor and with calibration for the front-end electronics of PET imaging

NASA Astrophysics Data System (ADS)

Liu, Wei; Wei, Tingcun; Li, Bo; Yang, Lifeng; Xue, Feifei; Hu, Yongcai

2016-05-01

This paper presents a 12-bit 1 MS/s successive approximation register-analog to digital converter (SAR-ADC) for the 32-channel front-end electronics of CZT-based PET imaging system. To reduce the capacitance mismatch, instead of the fractional capacitor, the unit capacitor is used as the bridge capacitor in the split-capacitor digital to analog converter (DAC) circuit. In addition, in order to eliminate the periodical DNL errors of -1 LSB which often exists in the SAR-ADC using the charge-redistributed DAC, a calibration algorithm is proposed and verified by the experiments. The proposed 12-bit 1 MS/s SAR-ADC is designed and implemented using a 0.35 μm CMOS technology, it occupies only an active area of 986×956 μm2. The measurement results show that, at the power supply of 3.3/5.0 V and the sampling rate of 1 MS/s, the ADC with calibration has a signal-to-noise-and-distortion ratio (SINAD) of 67.98 dB, the power dissipation of 5 mW, and a figure of merit (FOM) of 2.44 pJ/conv.-step. This ADC is with the features of high accuracy, low power and small layout area, it is especially suitable to the one-chip integration of the front-end readout electronics.

Local residue coupling strategies by neural network for InSAR phase unwrapping

NASA Astrophysics Data System (ADS)

Refice, Alberto; Satalino, Giuseppe; Chiaradia, Maria T.

1997-12-01

Phase unwrapping is one of the toughest problems in interferometric SAR processing. The main difficulties arise from the presence of point-like error sources, called residues, which occur mainly in close couples due to phase noise. We present an assessment of a local approach to the resolution of these problems by means of a neural network. Using a multi-layer perceptron, trained with the back- propagation scheme on a series of simulated phase images, fashion the best pairing strategies for close residue couples. Results show that god efficiencies and accuracies can have been obtained, provided a sufficient number of training examples are supplied. Results show that good efficiencies and accuracies can be obtained, provided a sufficient number of training examples are supplied. The technique is tested also on real SAR ERS-1/2 tandem interferometric images of the Matera test site, showing a good reduction of the residue density. The better results obtained by use of the neural network as far as local criteria are adopted appear justified given the probabilistic nature of the noise process on SAR interferometric phase fields and allows to outline a specifically tailored implementation of the neural network approach as a very fast pre-processing step intended to decrease the residue density and give sufficiently clean images to be processed further by more conventional techniques.

Integrated Shoreline Extraction Approach with Use of Rasat MS and SENTINEL-1A SAR Images

NASA Astrophysics Data System (ADS)

Demir, N.; Oy, S.; Erdem, F.; Şeker, D. Z.; Bayram, B.

2017-09-01

Shorelines are complex ecosystems and highly important socio-economic environments. They may change rapidly due to both natural and human-induced effects. Determination of movements along the shoreline and monitoring of the changes are essential for coastline management, modeling of sediment transportation and decision support systems. Remote sensing provides an opportunity to obtain rapid, up-to-date and reliable information for monitoring of shoreline. In this study, approximately 120 km of Antalya-Kemer shoreline which is under the threat of erosion, deposition, increasing of inhabitants and urbanization and touristic hotels, has been selected as the study area. In the study, RASAT pansharpened and SENTINEL-1A SAR images have been used to implement proposed shoreline extraction methods. The main motivation of this study is to combine the land/water body segmentation results of both RASAT MS and SENTINEL-1A SAR images to improve the quality of the results. The initial land/water body segmentation has been obtained using RASAT image by means of Random Forest classification method. This result has been used as training data set to define fuzzy parameters for shoreline extraction from SENTINEL-1A SAR image. Obtained results have been compared with the manually digitized shoreline. The accuracy assessment has been performed by calculating perpendicular distances between reference data and extracted shoreline by proposed method. As a result, the mean difference has been calculated around 1 pixel.

Computer simulation of a space SAR using a range-sequential processor for soil moisture mapping

NASA Technical Reports Server (NTRS)

Fujita, M.; Ulaby, F. (Principal Investigator)

1982-01-01

The ability of a spaceborne synthetic aperture radar (SAR) to detect soil moisture was evaluated by means of a computer simulation technique. The computer simulation package includes coherent processing of the SAR data using a range-sequential processor, which can be set up through hardware implementations, thereby reducing the amount of telemetry involved. With such a processing approach, it is possible to monitor the earth's surface on a continuous basis, since data storage requirements can be easily met through the use of currently available technology. The Development of the simulation package is described, followed by an examination of the application of the technique to actual environments. The results indicate that in estimating soil moisture content with a four-look processor, the difference between the assumed and estimated values of soil moisture is within + or - 20% of field capacity for 62% of the pixels for agricultural terrain and for 53% of the pixels for hilly terrain. The estimation accuracy for soil moisture may be improved by reducing the effect of fading through non-coherent averaging.

CryoSat Ice Processor: High-Level Overview of Baseline-C Data and Quality-Control

NASA Astrophysics Data System (ADS)

Mannan, R.; Webb, E.; Hall, A.; Bouffard, J.; Femenias, P.; Parrinello, T.; Bouffard, J.; Brockley, D.; Baker, S.; Scagliola, M.; Urien, S.

2016-08-01

Since April 2015, the CryoSat ice products have been generated with the new Baseline-C Instrument Processing Facilities (IPFs). This represents a major upgrade to the CryoSat ice IPFs and is the baseline for the second CryoSat Reprocessing Campaign. Baseline- C introduces major evolutions with respect to Baseline- B, most notably the release of freeboard data within the L2 SAR products, following optimisation of the SAR retracker. Additional L2 improvements include a new Arctic Mean Sea Surface (MSS) in SAR; a new tuneable land ice retracker in LRM; and a new Digital Elevation Model (DEM) in SARIn. At L1B new attitude fields have been introduced and existing datation and range biases reduced. This paper provides a high level overview of the changes and evolutions implemented at Baseline-C in order to improve CryoSat L1B and L2 data characteristics and exploitation over polar regions. An overview of the main Quality Control (QC) activities performed on operational Baseline-C products is also presented.

The Asia-RiCE activity with data cube

NASA Astrophysics Data System (ADS)

Oyoshi, K.; Sobue, S.; LE Toan, T.; Lam, N. D.

2017-12-01

The Asia-RiCE initiative (http://www.asia-rice.org) has been organized to enhance rice production estimates through the use of Earth observation satellites data, and seeks to ensure that Asian rice crops are appropriately represented within GEO Global Agriculture Monitoring (GEO-GLAM) to support FAO Agriculture Market Information System (FAO-AMIS). Asia-RiCE is composed of national teams that are actively contributing to the Crop Monitor for AMIS and developing technical demonstrations of rice crop monitoring activities using both Synthetic Aperture Radar (SAR) data (Radarsat-2 from 2013; Sentinel-1 and ALOS-2 from 2015.From 2016 after the successful rice crop area and growing estimation using SAR in a technical demonstration site (provincial level), wall-to-wall (national scale) excurse as phase 2 has been implemented in Vietnam and Indonesia in cooperation with ministry of agriculture and space agencies. This paper reports this year activity of 2017 accomplishment and way forward, especially for analysis ready data (ARD) definition of SAR to ingest to CEOS data cube to provide national scale service in Vietnam and Indonesia.

LDRD final report :

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brost, Randolph C.; McLendon, William Clarence,

2013-01-01

Modeling geospatial information with semantic graphs enables search for sites of interest based on relationships between features, without requiring strong a priori models of feature shape or other intrinsic properties. Geospatial semantic graphs can be constructed from raw sensor data with suitable preprocessing to obtain a discretized representation. This report describes initial work toward extending geospatial semantic graphs to include temporal information, and initial results applying semantic graph techniques to SAR image data. We describe an efficient graph structure that includes geospatial and temporal information, which is designed to support simultaneous spatial and temporal search queries. We also report amore » preliminary implementation of feature recognition, semantic graph modeling, and graph search based on input SAR data. The report concludes with lessons learned and suggestions for future improvements.« less

Hospital design for better infection control

PubMed Central

Lateef, Fatimah

2009-01-01

The physical design and infrastructure of a hospital or institution is an essential component of its infection control measure. Thus is must be a prerequisite to take these into consideration from the initial conception and planning stages of the building. The balance between designing a hospital to be an open, accessible and public place and the control to reduce the spread of infections diseases is a necessity. At Singapore General Hospital, many lessons were learnt during the SARS outbreak pertaining to this. During and subsequent to the SARS outbreak, many changes evolved in the hospital to enable us to handle and face any emerging infectious situation with calm, confidence and the knowledge that staff and patients will be in good stead. This paper will share some of our experiences as well as challenges PMID:20009307

Global Hawk: Root Cause Analysis of Projected Unit Cost Growth

DTIC Science & Technology

2011-05-01

December 2009 Selected Acquisition Report (SAR), an Initial Operational Test & v Evaluation (“ IOT &E Phase II”) was planned for July–October 2010. The...PAT & mod facility 8% Diminishing Mfg Sources 3% “ IOT &E Replan” 3% ASIP calibration facility 1% Revised Cost Estimates Missing CDD Content...Diminishing Manufacturing Sources (DMS) ..............................................20 j. “ IOT &E Replan

76 FR 55334 - Maintenance of and Access to Records Pertaining to Individuals; Proposed Exemption

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-07

...--the Suspicious Activity Reporting (SAR) database--to be used to track observed behavior reasonably indicative of pre-operational planning related to terrorism or other criminal activity. To aid in the law... information in the file; however, given the exemption from (d), above, the subject has no way to verify what...

Dynamic Programming Algorithms for Planning and Robotics in Continuous Domains and the Hamilton-Jacobi Equation

DTIC Science & Technology

2008-09-22

provision of law, no person shall be subject to a penalty for failing to comply with a collection of information if it does not display a currently...CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 72 19a. NAME OF RESPONSIBLE PERSON a . REPORT unclassified b...2008 Ian Mitchell, University of British Columbia 3 Basic Path Planning • Find the optimal path p(s) to a target (or from a source) • Inputs – Cost c

Improved inland water levels from SAR altimetry using novel empirical and physical retrackers

NASA Astrophysics Data System (ADS)

Villadsen, Heidi; Deng, Xiaoli; Andersen, Ole B.; Stenseng, Lars; Nielsen, Karina; Knudsen, Per

2016-06-01

Satellite altimetry has proven a valuable resource of information on river and lake levels where in situ data are sparse or non-existent. In this study several new methods for obtaining stable inland water levels from CryoSat-2 Synthetic Aperture Radar (SAR) altimetry are presented and evaluated. In addition, the possible benefits from combining physical and empirical retrackers are investigated. The retracking methods evaluated in this paper include the physical SAR Altimetry MOde Studies and Applications (SAMOSA3) model, a traditional subwaveform threshold retracker, the proposed Multiple Waveform Persistent Peak (MWaPP) retracker, and a method combining the physical and empirical retrackers. Using a physical SAR waveform retracker over inland water has not been attempted before but shows great promise in this study. The evaluation is performed for two medium-sized lakes (Lake Vänern in Sweden and Lake Okeechobee in Florida), and in the Amazon River in Brazil. Comparing with in situ data shows that using the SAMOSA3 retracker generally provides the lowest root-mean-squared-errors (RMSE), closely followed by the MWaPP retracker. For the empirical retrackers, the RMSE values obtained when comparing with in situ data in Lake Vänern and Lake Okeechobee are in the order of 2-5 cm for well-behaved waveforms. Combining the physical and empirical retrackers did not offer significantly improved mean track standard deviations or RMSEs. Based on these studies, it is suggested that future SAR derived water levels are obtained using the SAMOSA3 retracker whenever information about other physical properties apart from range is desired. Otherwise we suggest using the empirical MWaPP retracker described in this paper, which is both easy to implement, computationally efficient, and gives a height estimate for even the most contaminated waveforms.

Sentinel-3 SAR Altimetry over Coastal and Open Ocean: performance assessment and improved retrieval methods in the ESA SCOOP Project.

NASA Astrophysics Data System (ADS)

Benveniste, J.; Cotton, D.; Moreau, T.; Raynal, M.; Varona, E.; Cipollini, P.; Cancet, M.; Martin, F.; Fenoglio-Marc, L.; Naeije, M.; Fernandes, J.; Lazaro, C.; Restano, M.; Ambrózio, A.

2017-12-01

The ESA Sentinel-3 satellite, launched in February 2016 as a part of the Copernicus programme, is the second satellite to operate a SAR mode altimeter. The Sentinel 3 Synthetic Aperture Radar Altimeter (SRAL) is based on the heritage from Cryosat-2, but this time complemented by a Microwave Radiometer (MWR) to provide a wet troposphere correction, and operating at Ku and C-Bands to provide an accurate along-track ionospheric correction. The SRAL is operated in SAR mode over the whole ocean and promises increased performance w.r.t. conventional altimetry. SCOOP (SAR Altimetry Coastal & Open Ocean Performance) is a project funded under the ESA SEOM (Scientific Exploitation of Operational Missions) Programme Element, started in September 2015, to characterise the expected performance of Sentinel-3 SRAL SAR mode altimeter products, in the coastal zone and open-ocean, and then to develop and evaluate enhancements to the baseline processing scheme in terms of improvements to ocean measurements. There is also a work package to develop and evaluate an improved Wet Troposphere correction for Sentinel-3, based on the measurements from the on-board MWR, further enhanced mostly in the coastal and polar regions using third party data, and provide recommendations for use. In this presentation we present results from the SCOOP project that demonstrate the excellent performance of SRAL in terms of measurement precision, and we illustrate the development and testing of new processing approaches designed specifically to improve performance close to the coast. The SCOOP test data sets and relevant documentation are available to external researchers on application to the project team. At the end of the project recommendations for further developments and implementations will be provided through a scientific roadmap.

Observing the Microseism Source Regions from Space

NASA Astrophysics Data System (ADS)

Simard, M.; Kedar, S.; Rodriguez, E.; Webb, F. H.

2005-12-01

Correlations of this ambient seismic signal between seismic stations has recently emerged as a powerful technique for tomography of the Earth's crust, allowing continuous global monitoring of the crust to seismogenic depths without relying on the occurrence of earthquakes. The technique has the potential for resolving changes in the crust during periods of little or no earthquake activity. Since ambient seismic noise is predominantly generated by ocean wave-wave interactions known to originate in narrowly defined geographical source areas that vary according to ocean swell state and season, it may be possible to derive physical constraints of the source characteristics by globallyly observing candidate source regions from space. At present, such observations have been confined to point measurements such as directional buoys and ocean-bottom seismometers. Using a technique formulated by Engen and Jonsen [1995], a 'field view' of the generating region can be obtained by deriving ocean directional spectra from Synthetic Aperature Radar (SAR) images by analysis of cross correlation of single-look SAR images. In November 2004, the Jet Propulsion Laboratory's (JPL) air-borne SAR instrument, has collected data off the Alaska coast, while a large storm with wave heights of ~8m was pounding the coast. This was contemporaneous with the recording of strong microseismic activity by the Canadian National Seismic (CNSN). The AirSAR collected over a 100km long, 10km wide swath offshore, the region most likely to involve wave-wave interaction between the incoming swell and coast-reflected waves. JPL has implemented the cross correlation spectral technique, and applied it to the 2004 data-set. We will present results of the analysis of the SAR data in conjunction with analysis of the CNSN broadband seismic data.

Global Characterization of Tropospheric Noise for InSAR Analysis Using MODIS Data

NASA Astrophysics Data System (ADS)

Yun, S.; Hensley, S.; Chaubell, M.; Fielding, E. J.; Pan, L.; Rosen, P. A.

2013-12-01

Radio wave's differential phase delay variation through the troposphere is one of the largest error sources in Interferometric Synthetic Aperture Radar (InSAR) measurements, and water vapor variability in the troposphere is known to be the dominant factor. We use the precipitable water vapor products from NASA's Moderate Resolution Imaging Spectroradiometer (MODIS) sensors mounted on Terra and Aqua satellites to produce tropospheric noise maps of InSAR. Then we extract a small set of characteristic parameters of its power spectral density curve and 1-D covariance function, and calculate the structure function to estimate the expected tropospheric noise level as a function of distance. The results serve two purposes: 1) to provide guidance on the expected covariance matrix for geophysical modeling, 2) to provide quantitative basis of the measurement requirements for the planned US L-band SAR mission. We build over a decade span (2000-2013) of a lookup table of the parameters derived from 2-by-2 degree tiles at 1-by-1 degree posting of global coverage, representing 10 days of each season in each year. The MODIS data were retrieved from OSCAR (Online Services for Correcting Atmosphere in Radar) server. MODIS images with 5 percent or more cloud cover were discarded. Cloud mask and sensor scanning artifacts were removed with interpolation and spectral filtering, respectively. We also mitigate topography dependent stratified tropospheric delay variation using the European Centre for Medium-Range Weather Forecasts (ECMWF) and Shuttle Radar Topography Mission Digital Elevation Models (SRTM DEMs).

a High Precision dem Extraction Method Based on Insar Data

NASA Astrophysics Data System (ADS)

Wang, Xinshuang; Liu, Lingling; Shi, Xiaoliang; Huang, Xitao; Geng, Wei

2018-04-01

In the 13th Five-Year Plan for Geoinformatics Business, it is proposed that the new InSAR technology should be applied to surveying and mapping production, which will become the innovation driving force of geoinformatics industry. This paper will study closely around the new outline of surveying and mapping and then achieve the TerraSAR/TanDEM data of Bin County in Shaanxi Province in X band. The studying steps are as follows; Firstly, the baseline is estimated from the orbital data; Secondly, the interferometric pairs of SAR image are accurately registered; Thirdly, the interferogram is generated; Fourth, the interferometric correlation information is estimated and the flat-earth phase is removed. In order to solve the phase noise and the discontinuity phase existing in the interferometric image of phase, a GAMMA adaptive filtering method is adopted. Aiming at the "hole" problem of missing data in low coherent area, the interpolation method of low coherent area mask is used to assist the phase unwrapping. Then, the accuracy of the interferometric baseline is estimated from the ground control points. Finally, 1 : 50000 DEM is generated, and the existing DEM data is used to verify the accuracy through statistical analysis. The research results show that the improved InSAR data processing method in this paper can obtain the high-precision DEM of the study area, exactly the same with the topography of reference DEM. The R2 can reach to 0.9648, showing a strong positive correlation.

InSAR atmospheric correction using Himawari-8 Geostationary Meteorological Satellite

NASA Astrophysics Data System (ADS)

Kinoshita, Y.; Nimura, T.; Furuta, R.

2017-12-01

The atmospheric delay effect is one of the limitations for the accurate surface displacement detection by Synthetic Aperture Radar Interferometry (InSAR). Many previous studies have attempted to mitigate the neutral atmospheric delay in InSAR (e.g. Jolivet et al. 2014; Foster et al. 2006; Kinoshita et al. 2013). Hanssen et al. (2001) investigated the relationship between the 27 hourly observations of GNSS precipitable water vapor (PWV) and the infrared brightness temperature derived from visible satellite imagery, and showed a good correlation. Here we showed a preliminary result of the newly developed method for the neutral atmospheric delay correction using the Himawari-8 Japanese geostationary meteorological satellite data. The Himawari-8 satellite is the Japanese state-of-the-art geostationary meteorological satellite that has 16 observation channels and has spatial resolutions of 0.5 km (visible) and 2.0 km (near-infrared and infrared) with an time interval of 2.5 minutes around Japan. To estimate the relationship between the satellite brightness temperature and the atmospheric delay amount. Since the InSAR atmospheric delay is principally the same as that in GNSS, we at first compared the Himawari-8 data with the GNSS zenith tropospheric delay data derived from the Japanese dense GNSS network. The comparison of them showed that the band with the wavelength of 6.9 μm had the highest correlation to the GNSS observation. Based on this result, we developed an InSAR atmospheric delay model that uses the Himawari-8 6.9 μm band data. For the model validation, we generated InSAR images from the ESA's C-band Sentinel-1 SLC data with the GAMMA SAR software. We selected two regions around Tokyo and Sapporo (both in Japan) as the test sites because of the less temporal decorrelation. The validation result showed that the delay model reasonably estimate large scale phase variation whose spatial scale was on the order of over 20 km. On the other hand, phase variations of a few km scale were not estimated by the model. This would be due to the horizontal resolution of the input data (2 km in the 6.9 μm band). In the presentation we will show these results and the progress after the abstract submission, and discuss the limitation of our method and the future research plan.

On board processor development for NASA's spaceborne imaging radar with system-on-chip technology

NASA Technical Reports Server (NTRS)

Fang, Wai-Chi

2004-01-01

This paper reports a preliminary study result of an on-board spaceborne SAR processor. It consists of a processing requirement analysis, functional specifications, and implementation with system-on-chip technology. Finally, a minimum version of this on-board processor designed for performance evaluation and for partial demonstration is illustrated.

Application of the SAROTA index in real-life scenario

NASA Astrophysics Data System (ADS)

Rojatkar, A.; Monebhurrun, V.

2014-10-01

A unique parameter referred to as the SAROTA index which accounts for both the specific absorption rate (SAR) and the over-the-air (OTA) performance of a mobile phone was previously proposed to characterize the real-life exposure. The applicability of the SAROTA index was confirmed using SAR and total radiated power (TRP) data obtained under laboratory conditions wherein the power control (PC) enforced on the mobile phone was implemented artificially. Herein the investigation is extended to measurements conducted for the speech mode of operation in real-life scenarios. Based on the actual PC implemented during the communication with the base station, the instantaneous and average real-life exposure experienced by the mobile phone user is analyzed and compared to the predicted SAROTA index. To capture the PC in real-time, a set of hardware modified phones with embedded network monitoring software are used. The instantaneous uplink transmit power level (TX_LEV) along with various downlink parameters such as the receive signal level (RX_LEV) and received signal quality (RX_QUAL) of the communication link are thus available for performing a comprehensive RF exposure analysis.

The GEDI Strategy for Improved Mapping of Forest Biomass and Structure

NASA Astrophysics Data System (ADS)

Dubayah, R.

2017-12-01

In 2014 the Committee on Earth Observation Satellites (CEOS) published a comprehensive report on approaches to meet future requirements for space-based observations of carbon. Entitled the CEOS Strategy for Carbon Observations from Space and endorsed by its member space agencies, the report outlines carbon information needs for climate and other policy, and how these needs may be met through existing and planned satellite missions. The CEOS Strategymakes recommendations for new, high-priority measurements. Among these is that space-based measurements using lidar should have priority to provide information on height, structure and biomass, complementing the existing and planned suite of SAR missions, such as the NASA NISAR and ESA BIOMASS missions. NASA's Global Ecosystem Dynamics Investigation (GEDI) directly meets this challenge. Scheduled for launch in late 2018 for deployment on the International Space Station, GEDI will provide more than 12 billion observations of canopy height, vertical structure and topography using a 10-beam lidar optimized for ecosystem measurements. Central to the success of GEDI is the development of calibration equations that relate observed forest structure to biomass at a variety of spatial scales. GEDI creates these calibrations by combining a large data base of field plot measurements with coincident airborne lidar observations that are used to simulate GEDI lidar waveforms. GEDI uses these relatively sparse footprint estimates of structure and biomass to create lower resolution, but spatially continuous grids of structure and biomass. GEDI is also developing radar/lidar fusion algorithms to produce higher-resolution, spatially continuous estimates of canopy height and biomass in collaboration with the German Aerospace Center (DLR). In this talk we present the current status of the GEDI calibration and validation program, and its approach for fusing its observations with the next generation of SAR sensors for improved mapping of forest structure from space. As stressed by the CEOS Strategy, the success of these efforts will critically depend on enhanced intra- and inter-mission calibration and validation activities, underpinned by an expanding network of in situ field observations, such as being implemented by GEDI.

Change detection in a time series of polarimetric SAR data by an omnibus test statistic and its factorization (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nielsen, Allan A.; Conradsen, Knut; Skriver, Henning

2016-10-01

Test statistics for comparison of real (as opposed to complex) variance-covariance matrices exist in the statistics literature [1]. In earlier publications we have described a test statistic for the equality of two variance-covariance matrices following the complex Wishart distribution with an associated p-value [2]. We showed their application to bitemporal change detection and to edge detection [3] in multilook, polarimetric synthetic aperture radar (SAR) data in the covariance matrix representation [4]. The test statistic and the associated p-value is described in [5] also. In [6] we focussed on the block-diagonal case, we elaborated on some computer implementation issues, and we gave examples on the application to change detection in both full and dual polarization bitemporal, bifrequency, multilook SAR data. In [7] we described an omnibus test statistic Q for the equality of k variance-covariance matrices following the complex Wishart distribution. We also described a factorization of Q = R2 R3 … Rk where Q and Rj determine if and when a difference occurs. Additionally, we gave p-values for Q and Rj. Finally, we demonstrated the use of Q and Rj and the p-values to change detection in truly multitemporal, full polarization SAR data. Here we illustrate the methods by means of airborne L-band SAR data (EMISAR) [8,9]. The methods may be applied to other polarimetric SAR data also such as data from Sentinel-1, COSMO-SkyMed, TerraSAR-X, ALOS, and RadarSat-2 and also to single-pol data. The account given here closely follows that given our recent IEEE TGRS paper [7]. Selected References [1] Anderson, T. W., An Introduction to Multivariate Statistical Analysis, John Wiley, New York, third ed. (2003). [2] Conradsen, K., Nielsen, A. A., Schou, J., and Skriver, H., "A test statistic in the complex Wishart distribution and its application to change detection in polarimetric SAR data," IEEE Transactions on Geoscience and Remote Sensing 41(1): 4-19, 2003. [3] Schou, J., Skriver, H., Nielsen, A. A., and Conradsen, K., "CFAR edge detector for polarimetric SAR images," IEEE Transactions on Geoscience and Remote Sensing 41(1): 20-32, 2003. [4] van Zyl, J. J. and Ulaby, F. T., "Scattering matrix representation for simple targets," in Radar Polarimetry for Geoscience Applications, Ulaby, F. T. and Elachi, C., eds., Artech, Norwood, MA (1990). [5] Canty, M. J., Image Analysis, Classification and Change Detection in Remote Sensing,with Algorithms for ENVI/IDL and Python, Taylor & Francis, CRC Press, third revised ed. (2014). [6] Nielsen, A. A., Conradsen, K., and Skriver, H., "Change detection in full and dual polarization, single- and multi-frequency SAR data," IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 8(8): 4041-4048, 2015. [7] Conradsen, K., Nielsen, A. A., and Skriver, H., "Determining the points of change in time series of polarimetric SAR data," IEEE Transactions on Geoscience and Remote Sensing 54(5), 3007-3024, 2016. [9] Christensen, E. L., Skou, N., Dall, J., Woelders, K., rgensen, J. H. J., Granholm, J., and Madsen, S. N., "EMISAR: An absolutely calibrated polarimetric L- and C-band SAR," IEEE Transactions on Geoscience and Remote Sensing 36: 1852-1865 (1998).

Crop Identification Using Time Series of Landsat-8 and Radarsat-2 Images: Application in a Groundwater Irrigated Region, South India

NASA Astrophysics Data System (ADS)

Sharma, A. K.; Hubert-Moy, L.; Betbederet, J.; Ruiz, L.; Sekhar, M.; Corgne, S.

2016-08-01

Monitoring land use and land cover and more particularly irrigated cropland dynamics is of great importance for water resources management and land use planning. The objective of this study was to evaluate the combined use of multi-temporal optical and radar data with a high spatial resolution in order to improve the precision of irrigated crop identification by taking into account information on crop phenological stages. SAR and optical parameters were derived from time- series of seven quad-pol RADARSAT-2 and four Landsat-8 images which were acquired on the Berambadi catchment, South India, during the monsoon crop season at the growth stages of turmeric crop. To select the best parameter to discriminate turmeric crops, an analysis of covariance (ANCOVA) was applied on all the time-series parameters and the most discriminant ones were classified using the Support Vector Machine (SVM) technique. Results show that in absence of optical images, polarimetric parameters derived from SAR time-series can be used for the turmeric area estimates and that the combined use of SAR and optical parameters can improve the classification accuracy to identify turmeric.

Human exposure assessment in the near field of GSM base-station antennas using a hybrid finite element/method of moments technique.

PubMed

Meyer, Frans J C; Davidson, David B; Jakobus, Ulrich; Stuchly, Maria A

2003-02-01

A hybrid finite-element method (FEM)/method of moments (MoM) technique is employed for specific absorption rate (SAR) calculations in a human phantom in the near field of a typical group special mobile (GSM) base-station antenna. The MoM is used to model the metallic surfaces and wires of the base-station antenna, and the FEM is used to model the heterogeneous human phantom. The advantages of each of these frequency domain techniques are, thus, exploited, leading to a highly efficient and robust numerical method for addressing this type of bioelectromagnetic problem. The basic mathematical formulation of the hybrid technique is presented. This is followed by a discussion of important implementation details-in particular, the linear algebra routines for sparse, complex FEM matrices combined with dense MoM matrices. The implementation is validated by comparing results to MoM (surface equivalence principle implementation) and finite-difference time-domain (FDTD) solutions of human exposure problems. A comparison of the computational efficiency of the different techniques is presented. The FEM/MoM implementation is then used for whole-body and critical-organ SAR calculations in a phantom at different positions in the near field of a base-station antenna. This problem cannot, in general, be solved using the MoM or FDTD due to computational limitations. This paper shows that the specific hybrid FEM/MoM implementation is an efficient numerical tool for accurate assessment of human exposure in the near field of base-station antennas.

Unsupervised DInSAR processing chain for multi-scale displacement analysis

NASA Astrophysics Data System (ADS)

Casu, Francesco; Manunta, Michele

2016-04-01

Earth Observation techniques can be very helpful for the estimation of several sources of ground deformation due to their characteristics of large spatial coverage, high resolution and cost effectiveness. In this scenario, Differential Synthetic Aperture Radar Interferometry (DInSAR) is one of the most effective methodologies for its capability to generate spatially dense deformation maps at both global and local spatial scale, with centimeter to millimeter accuracy. DInSAR exploits the phase difference (interferogram) between SAR image pairs relevant to acquisitions gathered at different times, but with the same illumination geometry and from sufficiently close flight tracks, whose separation is typically referred to as baseline. Among several, the SBAS algorithm is one of the most used DInSAR approaches and it is aimed at generating displacement time series at a multi-scale level by exploiting a set of small baseline interferograms. SBAS, and generally DInSAR, has taken benefit from the large availability of spaceborne SAR data collected along years by several satellite systems, with particular regard to the European ERS and ENVISAT sensors, which have acquired SAR images worldwide during approximately 20 years. Moreover, since 2014 the new generation of Copernicus Sentinel satellites has started to acquire data with a short revisit time (12 days) and a global coverage policy, thus flooding the scientific EO community with an unprecedent amount of data. To efficiently manage such amount of data, proper processing facilities (as those coming from the emerging Cloud Computing technologies) have to be used, as well as novel algorithms aimed at their efficient exploitation have to be developed. In this work we present a set of results achieved by exploiting a recently proposed implementation of the SBAS algorithm, namely Parallel-SBAS (P-SBAS), which allows us to effectively process, in an unsupervised way and in a limited time frame, a huge number of SAR images, thus leading to the generation of Interferometric products for both global and local scale displacement analysis. Among several examples, we will show a wide displacement SBAS processing, carried out over the southern California, during which the whole ascending ENVISAT data set of more than 740 images has been fully processed on a Cloud Computing environment in less than 9 hours, leading to the generation of a displacement map of about 150,000 square kilometres. The P-SBAS characteristics allowed also us to integrate the algorithm within the ESA Geohazard Exploitation Platform (GEP), which is based on the use of GRID and Cloud Computing facilities, thus making freely available to the EO community a web tool for massive and systematic interferometric displacement time series generation. This work has been partially supported by: the Italian MIUR under the RITMARE project; the CNR-DPC agreement and the ESA GEP project.

A Hybrid-Cloud Science Data System Enabling Advanced Rapid Imaging & Analysis for Monitoring Hazards

NASA Astrophysics Data System (ADS)

Hua, H.; Owen, S. E.; Yun, S.; Lundgren, P.; Moore, A. W.; Fielding, E. J.; Radulescu, C.; Sacco, G.; Stough, T. M.; Mattmann, C. A.; Cervelli, P. F.; Poland, M. P.; Cruz, J.

2012-12-01

Volcanic eruptions, landslides, and levee failures are some examples of hazards that can be more accurately forecasted with sufficient monitoring of precursory ground deformation, such as the high-resolution measurements from GPS and InSAR. In addition, coherence and reflectivity change maps can be used to detect surface change due to lava flows, mudslides, tornadoes, floods, and other natural and man-made disasters. However, it is difficult for many volcano observatories and other monitoring agencies to process GPS and InSAR products in an automated scenario needed for continual monitoring of events. Additionally, numerous interoperability barriers exist in multi-sensor observation data access, preparation, and fusion to create actionable products. Combining high spatial resolution InSAR products with high temporal resolution GPS products--and automating this data preparation & processing across global-scale areas of interests--present an untapped science and monitoring opportunity. The global coverage offered by satellite-based SAR observations, and the rapidly expanding GPS networks, can provide orders of magnitude more data on these hazardous events if we have a data system that can efficiently and effectively analyze the voluminous raw data, and provide users the tools to access data from their regions of interest. Currently, combined GPS & InSAR time series are primarily generated for specific research applications, and are not implemented to run on large-scale continuous data sets and delivered to decision-making communities. We are developing an advanced service-oriented architecture for hazard monitoring leveraging NASA-funded algorithms and data management to enable both science and decision-making communities to monitor areas of interests via seamless data preparation, processing, and distribution. Our objectives: * Enable high-volume and low-latency automatic generation of NASA Solid Earth science data products (InSAR and GPS) to support hazards monitoring. * Facilitate NASA-USGS collaborations to share NASA InSAR and GPS data products, which are difficult to process in high-volume and low-latency, for decision-support. * Enable interoperable discovery, access, and sharing of NASA observations and derived actionable products, and between the observation and decision-making communities. * Enable their improved understanding through visualization, mining, and cross-agency sharing. Existing InSAR & GPS processing packages and other software are integrated for generating geodetic decision support monitoring products. We employ semantic and cloud-based data management and processing techniques for handling large data volumes, reducing end product latency, codifying data system information with semantics, and deploying interoperable services for actionable products to decision-making communities.

Sentinel-1 - the radar mission for GMES operational land and sea services

NASA Astrophysics Data System (ADS)

Attema, Evert; Bargellini, Pierre; Edwards, Peter; Levrini, Guido; Lokas, Svein; Moeller, Ludwig; Rosich-Tell, Betlem; Secchi, Patrizia; Torres, Ramon; Davidson, Malcolm; Snoeij, Paul

2007-08-01

The ESA Sentinels will be the first series of operational satellites to meet the Earth observation needs of the European Union - ESA Global Monitoring for Environment and Security (GMES) programme. Existing and planned space assets will be complemented by new developments from ESA. The first is Sentinel-1, a pair of synthetic aperture radar (SAR) imaging satellites.

Determining River Ice Displacement Using the Differential Interferometry Synthetic Aperture Radar (D-InSAR) technique

NASA Astrophysics Data System (ADS)

Chu, T.; Lindenschmidt, K. E.

2016-12-01

Monitoring river ice cover dynamics during the course of winter is necessary to comprehend possible negative effects of ice on anthropogenic systems and natural ecosystems to provide a basis to develop mitigation measures. Due to their large scale and limited accessibility to most places along river banks, especially in northern regions, remote sensing techniques are a suitable approach for monitoring river ice regimes. Additionally, determining the vertical displacements of ice covers due to changes in flow provides an indication of vulnerable areas to initial cracking and breakup of the ice cover. Such information is paramount when deciding on suitable locations for winter road crossing along rivers. A number of RADARSAT-2 (RS-2) beam modes (i.e. Wide Fine, Wide Ultra-Fine, Wide Fine Quad Polarization and Spotlight) and D-InSAR methods were examined in this research to characterize slant range and vertical displacement of ice covers along the Slave River in the Northwest Territories, Canada. Our results demonstrate that the RS-2 Spotlight beam mode, processed by the Multiple Aperture InSAR (MAI) method, outperformed other beam modes and conventional InSAR when characterizing spatio-temporal patterns of ice surface fluctuations. For example, the MAI based Spotlight differential interferogram derived from the January and February 2016 images of the Slave River Delta resulted in a slant range displacement of the ice surface between -3.3 and +3.6 cm (vertical displacement between -4.3 and +4.8 cm), due to the changes in river flow and river ice morphology between the two acquisition dates. It is difficult to monitor the ice movement in early and late winter periods due to the loss of phase coherence and error in phase unwrapping. These findings are consistent with our river ice hydraulic modelling and visual interpretation of the river ice processes under different hydrometeorological conditions and river ice morphology. An extension of this study is planned to incorporate the results of ice cover displacement (rise/drop) to locate areas of initial breakup in an ice jam forecasting system. Keywords: D-InSAR, Mutiple Aperture Radar InSAR (MAI), river ice displacement, RADARSAT-2

UAVSAR Instrument: Current Operations and Planned Upgrades

NASA Technical Reports Server (NTRS)

Lou, Yunling; Hensley, Scott; Chao, Roger; Chapin, Elaine; Heavy, Brandon; Jones, Cathleen; Miller, Timothy; Naftel, Chris; Fratello, David

2011-01-01

The Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) instrument is a pod-based Lband polarimetric synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track SAR data for differential interferometric measurements. This instrument is currently installed on the NASA Gulfstream- III (G-III) aircraft with precision real-time Global Positioning System (GPS) and a sensor-controlled flight management system for precision repeat-pass data acquisitions. UAVSAR has conducted engineering and preliminary science data flights since October 2007 on the G-III. We are porting the radar to the Global Hawk Unmanned Airborne Vehicle (UAV) to enable long duration/long range data campaigns. We plan to install two radar pods (each with its own active array antenna) under the wings of the Global Hawk to enable the generation of precision topographic maps and single pass polarimetric-interferometry (SPI) providing vertical structure of ice and vegetation. Global Hawk's range of 8000 nm will enable regional surveys with far fewer sorties as well as measurements of remote locations without the need for long and complicated deployments. We are also developing P-band polarimetry and Ka-band single-pass interferometry capabilities on UAVSAR by replacing the radar antenna and front-end electronics to operate at these

Magnetic resonance safety and compatibility of tantalum markers used in proton beam therapy for intraocular tumors: A 7.0 Tesla study.

PubMed

Oberacker, Eva; Paul, Katharina; Huelnhagen, Till; Oezerdem, Celal; Winter, Lukas; Pohlmann, Andreas; Boehmert, Laura; Stachs, Oliver; Heufelder, Jens; Weber, Andreas; Rehak, Matus; Seibel, Ira; Niendorf, Thoralf

2017-10-01

Proton radiation therapy (PRT) is a standard treatment of uveal melanoma. PRT patients undergo implantation of ocular tantalum markers (OTMs) for treatment planning. Ultra-high-field MRI is a promising technique for 3D tumor visualization and PRT planning. This work examines MR safety and compatibility of OTMs at 7.0 Tesla. MR safety assessment included deflection angle measurements (DAMs), electromagnetic field (EMF) simulations for specific absorption rate (SAR) estimation, and temperature simulations for examining radiofrequency heating using a bow-tie dipole antenna for transmission. MR compatibility was assessed by susceptibility artifacts in agarose, ex vivo pig eyes, and in an ex vivo tumor eye using gradient echo and fast spin-echo imaging. DAM (α < 1 °) demonstrated no risk attributed to magnetically induced OTM deflection. EMF simulations showed that an OTM can be approximated by a disk, demonstrated the need for averaging masses of m ave  = 0.01 g to accommodate the OTM, and provided SAR 0.01g,maximum  = 2.64 W/kg (P in  = 1W) in OTM presence. A transfer function was derived, enabling SAR 0.01g estimation for individual patient scenarios without the OTM being integrated. Thermal simulations revealed minor OTM-related temperature increase (δT < 15 mK). Susceptibility artifact size (<8 mm) and location suggest no restrictions for MRI of the nervus opticus. OTMs are not a per se contraindication for MRI. Magn Reson Med 78:1533-1546, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

Integration of satellite radar interferometry into a GLOF early warning system: a pilot study from the Andes of Peru

NASA Astrophysics Data System (ADS)

Strozzi, Tazio; Wiesmann, Andreas; Caduff, Rafael; Frey, Holger; Huggel, Christian; Kääb, Andreas; Cochachin, Alejo

2015-04-01

Glacier lake outburst floods (GLOF) have killed thousands of people in the Andes of Peru and in many other high-mountain regions of the world. The last years have seen progress in the integrative assessment of related hazards, through combined focus on the glacier lake, its dam properties, and processes in the lake surrounding, including the position and fluctuations of the glacier tongue and potential displacements and thermal conditions of adjacent slopes. Only a transient perspective on these factors allows anticipating potential future developments. For a very limited number of cases worldwide, where GLOF hazards and risks have been recognized, early warning systems (EWS) have been developed and implemented. Lake 513 in the Cordillera Blanca of Peru is one of those. Structural GLOF mitigation measures (tunnels to lower the lake level) have been undertaken in the 1990s and could successfully reduce, but not fully prevent, impacts of a GLOF such as that of April 2010 triggered by a rock/ice avalanche from Mount Hualcán. The EWS was implemented during recent years and disposes of automatic cameras, geophones, river run-off measurements, a meteorological station, and real-time communication with the municipality of Carhuaz and the communities in the catchment. An EWS is by definition limited in its concept and Earth Observation (EO) data offer a promising possibility to complement the assessment of the current hazard. In particular, the monitoring and early detection of slope instabilities in ice, rock and sediments that could impact the lake and trigger a GLOF is still a major challenge. Therefore, the potential of optical and SAR satellite data is currently tested for integration into the EWS within the project S:GLA:MO (Slope stability and Glacier LAke MOnitoring) project, funded by the European Space Agency (ESA) in collaboration with the GLACIARES project supported by the Swiss Agency for Development and Cooperation. EO data (optical and SAR) are considered for the production of up-to-date Digital Elevation Models (DEM), for the monitoring of glaciers (extent and velocity fields), glacier lakes (area), and for the compilation of a landslide inventory and slope activity map. DEMs are produced either from TanDEM-X image pairs or very-high resolution optical stereo pairs. Landsat-8 images are used to derive glacier and lake outlines, the latter complemented by TerraSAR-X and Radarsat-2 very high-resolution image pairs. Very-high resolution SAR data are also used to derive glacier flow velocities, indicating high flow velocities of up to 200 m/a for many glaciers of the Cordillera Blanca. Advanced SAR interferometric (InSAR) processing with a series of sensors (ERS-1/2, ENVISAT, ALOS PALSAR, TerraSAR-X and Radarsat-2) is considered for the monitoring of slope instabilities. Our results for the pilot study indicate no major slope displacements around Lake 513 for the period 1995-2014, confirming related field investigations. Current limitations of the EO data analyses are related to difficulties of detecting slope displacements in steep areas (steeper than about 40°), and timely acquisition and processing of the data. Rather than serving a real-time warning purpose, the potential of InSAR-derived information for GLOF EWS lies therefore in the regular and repeated monitoring of slope deformation and instabilities, independent of meteorological conditions and over large areas, in order to facilitate the decision if and where ground-based instruments should be installed. In addition to the investigation of slope instabilities around Lake 531, many instable slopes were detected based on the InSAR data on a regional scale on both sides of the Rio Santa Valley in the Ancash region.

GIAnT - Generic InSAR Analysis Toolbox

NASA Astrophysics Data System (ADS)

Agram, P.; Jolivet, R.; Riel, B. V.; Simons, M.; Doin, M.; Lasserre, C.; Hetland, E. A.

2012-12-01

We present a computing framework for studying the spatio-temporal evolution of ground deformation from interferometric synthetic aperture radar (InSAR) data. Several open-source tools including Repeat Orbit Interferometry PACkage (ROI-PAC) and InSAR Scientific Computing Environment (ISCE) from NASA-JPL, and Delft Object-oriented Repeat Interferometric Software (DORIS), have enabled scientists to generate individual interferograms from raw radar data with relative ease. Numerous computational techniques and algorithms that reduce phase information from multiple interferograms to a deformation time-series have been developed and verified over the past decade. However, the sharing and direct comparison of products from multiple processing approaches has been hindered by - 1) absence of simple standards for sharing of estimated time-series products, 2) use of proprietary software tools with license restrictions and 3) the closed source nature of the exact implementation of many of these algorithms. We have developed this computing framework to address all of the above issues. We attempt to take the first steps towards creating a community software repository for InSAR time-series analysis. To date, we have implemented the short baseline subset algorithm (SBAS), NSBAS and multi-scale interferometric time-series (MInTS) in this framework and the associated source code is included in the GIAnT distribution. A number of the associated routines have been optimized for performance and scalability with large data sets. Some of the new features in our processing framework are - 1) the use of daily solutions from continuous GPS stations to correct for orbit errors, 2) the use of meteorological data sets to estimate the tropospheric delay screen and 3) a data-driven bootstrapping approach to estimate the uncertainties associated with estimated time-series products. We are currently working on incorporating tidal load corrections for individual interferograms and propagation of noise covariance models through the processing chain for robust estimation of uncertainties in the deformation estimates. We will demonstrate the ease of use of our framework with results ranging from regional scale analysis around Long Valley, CA and Parkfield, CA to continental scale analysis in Western South America. We will also present preliminary results from a new time-series approach that simultaneously estimates deformation over the complete spatial domain at all time epochs on a distributed computing platform. GIAnT has been developed entirely using open source tools and uses Python as the underlying platform. We build on the extensive numerical (NumPy) and scientific (SciPy) computing Python libraries to develop an object-oriented, flexible and modular framework for time-series InSAR applications. The toolbox is currently configured to work with outputs from ROI-PAC, ISCE and DORIS, but can easily be extended to support products from other SAR/InSAR processors. The toolbox libraries include support for hierarchical data format (HDF5) memory mapped files, parallel processing with Python's multi-processing module and support for many convex optimization solvers like CSDP, CVXOPT etc. An extensive set of routines to deal with ASCII and XML files has also been included for controlling the processing parameters.

1D-Var multilayer assimilation of X-band SAR data into a detailed snowpack model

NASA Astrophysics Data System (ADS)

Phan, X. V.; Ferro-Famil, L.; Gay, M.; Durand, Y.; Dumont, M.; Morin, S.; Allain, S.; D'Urso, G.; Girard, A.

2014-10-01

The structure and physical properties of a snowpack and their temporal evolution may be simulated using meteorological data and a snow metamorphism model. Such an approach may meet limitations related to potential divergences and accumulated errors, to a limited spatial resolution, to wind or topography-induced local modulations of the physical properties of a snow cover, etc. Exogenous data are then required in order to constrain the simulator and improve its performance over time. Synthetic-aperture radars (SARs) and, in particular, recent sensors provide reflectivity maps of snow-covered environments with high temporal and spatial resolutions. The radiometric properties of a snowpack measured at sufficiently high carrier frequencies are known to be tightly related to some of its main physical parameters, like its depth, snow grain size and density. SAR acquisitions may then be used, together with an electromagnetic backscattering model (EBM) able to simulate the reflectivity of a snowpack from a set of physical descriptors, in order to constrain a physical snowpack model. In this study, we introduce a variational data assimilation scheme coupling TerraSAR-X radiometric data into the snowpack evolution model Crocus. The physical properties of a snowpack, such as snow density and optical diameter of each layer, are simulated by Crocus, fed by the local reanalysis of meteorological data (SAFRAN) at a French Alpine location. These snowpack properties are used as inputs of an EBM based on dense media radiative transfer (DMRT) theory, which simulates the total backscattering coefficient of a dry snow medium at X and higher frequency bands. After evaluating the sensitivity of the EBM to snowpack parameters, a 1D-Var data assimilation scheme is implemented in order to minimize the discrepancies between EBM simulations and observations obtained from TerraSAR-X acquisitions by modifying the physical parameters of the Crocus-simulated snowpack. The algorithm then re-initializes Crocus with the modified snowpack physical parameters, allowing it to continue the simulation of snowpack evolution, with adjustments based on remote sensing information. This method is evaluated using multi-temporal TerraSAR-X images acquired over the specific site of the Argentière glacier (Mont-Blanc massif, French Alps) to constrain the evolution of Crocus. Results indicate that X-band SAR data can be taken into account to modify the evolution of snowpack simulated by Crocus.

On the Character and Mitigation of Atmospheric Noise in InSAR Time Series Analysis (Invited)

NASA Astrophysics Data System (ADS)

Barnhart, W. D.; Fielding, E. J.; Fishbein, E.

2013-12-01

Time series analysis of interferometric synthetic aperture radar (InSAR) data, with its broad spatial coverage and ability to image regions that are sometimes very difficult to access, is a powerful tool for characterizing continental surface deformation and its temporal variations. With the impending launch of dedicated SAR missions such as Sentinel-1, ALOS-2, and the planned NASA L-band SAR mission, large volume data sets will allow researchers to further probe ground displacement processes with increased fidelity. Unfortunately, the precision of measurements in individual interferograms is impacted by several sources of noise, notably spatially correlated signals caused by path delays through the stratified and turbulent atmosphere and ionosphere. Spatial and temporal variations in atmospheric water vapor often introduce several to tens of centimeters of apparent deformation in the radar line-of-sight, correlated over short spatial scales (<10 km). Signals resulting from atmospheric path delays are particularly problematic because, like the subsidence and uplift signals associated with tectonic deformation, they are often spatially correlated with topography. In this talk, we provide an overview of the effects of spatially correlated tropospheric noise in individual interferograms and InSAR time series analysis, and we highlight where common assumptions of the temporal and spatial characteristics of tropospheric noise fail. Next, we discuss two classes of methods for mitigating the effects of tropospheric water vapor noise in InSAR time series analysis and single interferograms: noise estimation and characterization with independent observations from multispectral sensors such as MODIS and MERIS; and noise estimation and removal with weather models, multispectral sensor observations, and GPS. Each of these techniques can provide independent assessments of the contribution of water vapor in interferograms, but each technique also suffers from several pitfalls that we outline. The multispectral near-infrared (NIR) sensors provide high spatial resolution (~1 km) estimates of total column tropospheric water vapor by measuring the absorption of reflected solar illumination and provide may excellent estimates of wet delay. The Online Services for Correcting Atmosphere in Radar (OSCAR) project currently provides water vapor products through web services (http://oscar.jpl.nasa.gov). Unfortunately, such sensors require daytime and cloudless observations. Global and regional numerical weather models can provide an additional estimate of both the dry and atmospheric delays with spatial resolution of (3-100 km) and time scales of 1-3 hours, though these models are of lower accuracy than imaging observations and are benefited by independent observations from independent observations of atmospheric water vapor. Despite these issues, the integration of these techniques for InSAR correction and uncertainty estimation may contribute substantially to the reduction and rigorous characterization of uncertainty in InSAR time series analysis - helping to expand the range of tectonic displacements imaged with InSAR, to robustly constrain geophysical models, and to generate a-priori assessments of satellite acquisitions goals.

Space Radar Image of West Texas - SAR Scan

NASA Image and Video Library

1999-04-15

This radar image of the Midland/Odessa region of West Texas, demonstrates an experimental technique, called ScanSAR, that allows scientists to rapidly image large areas of the Earth's surface. The large image covers an area 245 kilometers by 225 kilometers (152 miles by 139 miles). It was obtained by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) flying aboard the space shuttle Endeavour on October 5, 1994. The smaller inset image is a standard SIR-C image showing a portion of the same area, 100 kilometers by 57 kilometers (62 miles by 35 miles) and was taken during the first flight of SIR-C on April 14, 1994. The bright spots on the right side of the image are the cities of Odessa (left) and Midland (right), Texas. The Pecos River runs from the top center to the bottom center of the image. Along the left side of the image are, from top to bottom, parts of the Guadalupe, Davis and Santiago Mountains. North is toward the upper right. Unlike conventional radar imaging, in which a radar continuously illuminates a single ground swath as the space shuttle passes over the terrain, a Scansar radar illuminates several adjacent ground swaths almost simultaneously, by "scanning" the radar beam across a large area in a rapid sequence. The adjacent swaths, typically about 50 km (31 miles) wide, are then merged during ground processing to produce a single large scene. Illumination for this L-band scene is from the top of the image. The beams were scanned from the top of the scene to the bottom, as the shuttle flew from left to right. This scene was acquired in about 30 seconds. A normal SIR-C image is acquired in about 13 seconds. The ScanSAR mode will likely be used on future radar sensors to construct regional and possibly global radar images and topographic maps. The ScanSAR processor is being designed for 1996 implementation at NASA's Alaska SAR Facility, located at the University of Alaska Fairbanks, and will produce digital images from the forthcoming Canadian RADARSAT satellite. http://photojournal.jpl.nasa.gov/catalog/PIA01787

A strategy for Local Surface Stability Monitoring Using SAR Imagery

NASA Astrophysics Data System (ADS)

Kim, J.; Lan, C. W.; Lin, S. Y.; vanGasselt, S.; Yun, H.

2017-12-01

In order to provide sufficient facilities to satisfy a growing number of residents, nowadays there are many constructions and maintenance of infrastructures or buildings undergoing above and below the surface of urban area. In some cases we have learned that disasters might happen if the developments were conducted on unknown or geologically unstable ground or in over-developed areas. To avoid damages caused by such settings, it is essential to perform a regular monitoring scheme to understand the ground stability over the whole urban area. Through long-term monitoring, we firstly aim to observe surface stability over the construction sites. Secondly, we propose to implement an automatic extraction and tracking of suspicious unstable area. To achieve this, we used 12-days-interval C-band Sentinel-1A Synthetic Aperture Radar (SAR) images as the main source to perform regular monitoring. Differential Interferometric SAR (D-InSAR) technique was applied to generate interferograms. Together with the accumulation of updated Sentinel-1A SAR images, time series interferograms were formed accordingly. For the purpose of observing surface stability over known construction sites, the interferograms and the unwrapped products could be used to identify the surface displacement occurring before and after specific events. In addition, Small Baseline Subset (SBAS) and Permanent Scatterers (PS) approaches combining a set of unwrapped D-InSAR interferograms were also applied to derive displacement velocities over long-term periods. For some cases, we conducted the ascending and descending mode time series analysis to decompose three surface migration vectors and to precisely identify the risk pattern. Regarding the extraction of suspicious unstable areas, we propose to develop an automatic pattern recognition algorithm for the identification of specific fringe patterns involving various potential risks. The detected fringes were tracked in the time series interferograms and overlapped with various GIS layers to find correlations with the environmental elements causing the risks. Taipei City and Taichung City located in northern Taiwan and Ulsan City in Korea were selected to demonstrate the feasibility of the proposed method.

The 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR

USGS Publications Warehouse

Nealy, Jennifer; Benz, Harley M.; Hayes, Gavin; Berman, Eric; Barnhart, William

2017-01-01

The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 well-located events. In order to create this catalog, both subspace and kurtosis detectors are used to obtain an initial set of earthquakes and associated locations. The latter are then calibrated through the implementation of the hypocentroidal decomposition method and relocated using the BayesLoc relocation technique. We additionally perform a finite fault slip analysis of the mainshock using InSAR observations. By combining the relocated sequence with the finite fault analysis, we show that the aftershocks occur primarily updip and along the southwestern edge of the zone of maximum slip. The aftershock locations illuminate areas of post-mainshock strain increase; aftershock depths, ranging from 5 to 16 km, are consistent with InSAR imaging, which shows that the Wells earthquake was a buried source with no observable near-surface offset.

UAV-based L-band SAR with precision flight path control

NASA Astrophysics Data System (ADS)

Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Gregory A.; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul A.

2005-01-01

NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes1. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 m tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 m range resolution) and 16 km range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

UAV-Based L-Band SAR with Precision Flight Path Control

NASA Technical Reports Server (NTRS)

Madsen, Soren N.; Hensley, Scott; Wheeler, Kevin; Sadowy, Greg; Miller, Tim; Muellerschoen, Ron; Lou, Yunling; Rosen, Paul

2004-01-01

NASA's Jet Propulsion Laboratory is currently implementing a reconfigurable polarimetric L-band synthetic aperture radar (SAR), specifically designed to acquire airborne repeat track interferometric (RTI) SAR data, also know as differential interferometric measurements. Differential interferometry can provide key displacement measurements, important for the scientific studies of Earthquakes and volcanoes. Using precision real-time GPS and a sensor controlled flight management system, the system will be able to fly predefined paths with great precision. The radar will be designed to operate on a UAV (Unmanned Arial Vehicle) but will initially be demonstrated on a minimally piloted vehicle (MPV), such as the Proteus build by Scaled Composites. The application requires control of the flight path to within a 10 meter tube to support repeat track and formation flying measurements. The design is fully polarimetric with an 80 MHz bandwidth (2 meter range resolution) and 16 kilometer range swath. The antenna is an electronically steered array to assure that the actual antenna pointing can be controlled independent of the wind direction and speed. The system will nominally operate at 45,000 ft. The program started out as a Instrument Incubator Project (IIP) funded by NASA Earth Science and Technology Office (ESTO).

MR Fingerprinting Using The Quick Echo Splitting NMR Imaging Technique

PubMed Central

Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A.

2016-01-01

Purpose The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining Magnetic Resonance Fingerprinting (MRF) technique with Quick Echo Splitting NMR Imaging Technique (QUEST). Methods A QUEST-based MRF sequence was implemented to acquire high order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T1 and T2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The SAR of QUEST-MRF was compared to the clinically available methods. Results MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head Specific Absorption Rate (SAR) of 0.03 W/kg. T1 and T2 values estimated by MRF-QUEST are in good agreement with the traditional methods. Conclusion The combination of the MRF and the QUEST provides an accurate quantification of T1 and T2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. PMID:26924639

Robust Flood Monitoring Using Sentinel-1 SAR Time Series

NASA Astrophysics Data System (ADS)

DeVries, B.; Huang, C.; Armston, J.; Huang, W.

2017-12-01

The 2017 hurricane season in North and Central America has resulted in unprecedented levels of flooding that have affected millions of people and continue to impact communities across the region. The extent of casualties and damage to property incurred by these floods underscores the need for reliable systems to track flood location, timing and duration to aid response and recovery efforts. While a diverse range of data sources provide vital information on flood status in near real-time, only spaceborne Synthetic Aperture Radar (SAR) sensors can ensure wall-to-wall coverage over large areas, mostly independently of weather conditions or site accessibility. The European Space Agency's Sentinel-1 constellation represents the only SAR mission currently providing open access and systematic global coverage, allowing for a consistent stream of observations over flood-prone regions. Importantly, both the data and pre-processing software are freely available, enabling the development of improved methods, tools and data products to monitor floods in near real-time. We tracked flood onset and progression in Southeastern Texas, Southern Florida, and Puerto Rico using a novel approach based on temporal backscatter anomalies derived from times series of Sentinel-1 observations and historic baselines defined for each of the three sites. This approach was shown to provide a more objective measure of flood occurrence than the simple backscatter thresholds often employed in operational flood monitoring systems. Additionally, the use of temporal anomaly measures allowed us to partially overcome biases introduced by varying sensor view angles and image acquisition modes, allowing increased temporal resolution in areas where additional targeted observations are available. Our results demonstrate the distinct advantages offered by data from operational SAR missions such as Sentinel-1 and NASA's planned NISAR mission, and call attention to the continuing need for SAR Earth Observation missions that provide systematic repeat observations to facilitate continuous monitoring of flood-affected regions.

Multi-Temporal Multi-Sensor Analysis of Urbanization and Environmental/Climate Impact in China for Sustainable Urban Development

NASA Astrophysics Data System (ADS)

Ban, Yifang; Gong, Peng; Gamba, Paolo; Taubenbock, Hannes; Du, Peijun

2016-08-01

The overall objective of this research is to investigate multi-temporal, multi-scale, multi-sensor satellite data for analysis of urbanization and environmental/climate impact in China to support sustainable planning. Multi- temporal multi-scale SAR and optical data have been evaluated for urban information extraction using innovative methods and algorithms, including KTH- Pavia Urban Extractor, Pavia UEXT, and an "exclusion- inclusion" framework for urban extent extraction, and KTH-SEG, a novel object-based classification method for detailed urban land cover mapping. Various pixel- based and object-based change detection algorithms were also developed to extract urban changes. Several Chinese cities including Beijing, Shanghai and Guangzhou are selected as study areas. Spatio-temporal urbanization patterns and environmental impact at regional, metropolitan and city core were evaluated through ecosystem service, landscape metrics, spatial indices, and/or their combinations. The relationship between land surface temperature and land-cover classes was also analyzed.The urban extraction results showed that urban areas and small towns could be well extracted using multitemporal SAR data with the KTH-Pavia Urban Extractor and UEXT. The fusion of SAR data at multiple scales from multiple sensors was proven to improve urban extraction. For urban land cover mapping, the results show that the fusion of multitemporal SAR and optical data could produce detailed land cover maps with improved accuracy than that of SAR or optical data alone. Pixel-based and object-based change detection algorithms developed with the project were effective to extract urban changes. Comparing the urban land cover results from mulitemporal multisensor data, the environmental impact analysis indicates major losses for food supply, noise reduction, runoff mitigation, waste treatment and global climate regulation services through landscape structural changes in terms of decreases in service area, edge contamination and fragmentation. In terms ofclimate impact, the results indicate that land surface temperature can be related to land use/land cover classes.

Internal tide transformation across a continental slope off Cape Sines, Portugal

NASA Astrophysics Data System (ADS)

Small, Justin

2002-04-01

During the INTIFANTE 99 experiment in July 1999, observations were made of a prominent internal undular bore off Cape Sines, Portugal. The feature was always present and dominant in a collection of synthetic aperture radar (SAR) images of the area covering the period before, during and after the trial. During the trial, rapid dissemination of SAR data to the survey ship enabled assessment of the progression of the feature, and the consequent planning of a survey of the bore coincident with a new SAR image. Large amplitude internal waves of 50 m amplitude in 250 m water depth, and 40 m in 100 m depth, were observed. The images show that the position of the feature is linked to the phase of the tide, suggesting an internal tide origin. The individual packets of internal waves contain up to seven waves with wavelengths in the range of 500-1500 m, and successive packets are separated by internal tide distances of typically 16-20 km, suggesting phase speeds of 0.35-0.45 m s -1. The internal waves were coherent over crest lengths of between 15 and 70 km, the longer wavefronts being due to the merging of packets. This paper uses the SAR data to detail the transformation of the wave packet as it passes across the continental slope and approaches the coast. The generation sites for the feature are discussed and reasons for its unusually large amplitude are hypothesised. It is concluded that generation at critical slopes of the bathymetry and non-linear interactions are the likely explanations for the large amplitudes.

Interferometric Synthetic Aperture Radar to capture spatial variability of local land-based subsidence

NASA Astrophysics Data System (ADS)

Bekaert, D. P.; Hamlington, B.; Buzzanga, B. A.; Jones, C. E.

2017-12-01

The rate of relative sea level rise results from a combination of land subsidence and rising seas associated with global warming on long timescales and exacerbated by shifts in ocean dynamics on shorter timescales. An understanding of the current-day magnitude of each component is needed to create accurate projections of future relative sea level rise upon which to base planning efforts. Current day land-based subsidence rates derived from GPS often lack the spatial resolution to capture the local spatial variability needed when assessing the impact of relative sea-level rise. Interferometric Synthetic Aperture Radar (InSAR) is an attractive technique that has the potential to provide a measurement every 20-30m when good signal coherence is maintained. In practice, coastal regions are challenging for InSAR due to variable vegetation cover and soil moisture, which can be in part mitigated by applying advanced time-series InSAR techniques. After applying time-series InSAR, derived rates need to be combined with GPS to tie relative subsidence rates into a geodetic reference frame. Given the need to make projections of relative sea-level rise it is particularly important to propagate all uncertainties during the different processing stages. Here we provide results from ALOS and Sentinel-1 over Hampton Roads area in the Chesapeake Bay region, which is experiencing one of the highest rates of relative sea level rise on the Atlantic coast of the United States. Although the current derived subsidence rates have large uncertainties, it is expected that this will improve with the decadal observations from Sentinel-1.

Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

NASA Astrophysics Data System (ADS)

Avila-Olivera, Jorge A.; Farina, Paolo; Garduño-Monroy, Victor H.

2008-05-01

In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults "Oriente" and "Poniente". At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system "Taxco-San Miguel de Allende". In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create a map of the current phreatic level decline in city with the information of deep wells and using the "kriging" method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults "Oriente" and "Universidad Pedagógica" are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year.

Surface deformation monitoring of Sinabung volcano using multi temporal InSAR method and GIS analysis for affected area assessment

NASA Astrophysics Data System (ADS)

Aditiya, A.; Aoki, Y.; Anugrah, R. D.

2018-04-01

Sinabung Volcano which located in northern part of Sumatera island is part of a hundred active volcano in Indonesia. Surface deformation is detected over Sinabung Volcano and surrounded area since the first eruption in 2010 after 400 years long rest. We present multi temporal Interferometric Synthetic Aperture Radar (InSAR) time-series method of ALOS-2 L-band SAR data acquired from December 2014 to July 2017 to reveal surface deformation with high spatial resolution. The method includes focusing the SAR data, generating interferogram and phase unwrapping using SNAPHU tools. The result reveal significant deformation over Sinabung Volcano areas at rates up to 10 cm during observation period and the highest deformation occurs in western part which is trajectory of lava. We concluded the observed deformation primarily caused by volcanic activity respectively after long period of rest. In addition, Geographic Information System (GIS) analysis produces disaster affected areas of Sinabung eruption. GIS is reliable technique to estimate the impact of the hazard scenario to the exposure data and develop scenarios of disaster impacts to inform their contingency and emergency plan. The GIS results include the estimated affected area divided into 3 zones based on pyroclastic lava flow and pyroclastic fall (incandescent rock and ash). The highest impact is occurred in zone II due to many settlements are scattered in this zone. This information will be support stakeholders to take emergency preparation for disaster reduction. The continuation of this high rate of decline tends to endanger the population in next periods.

Interferometric investigations with the S1 constellation: an application to the Vesuvius/Campi Flegrei volcanic test site

NASA Astrophysics Data System (ADS)

Borgstrom, Sven; Del Gaudio, Carlo; De Martino, Prospero; Siniscalchi, Valeria; Prats-Iraola, Pau; Nannini, Matteo; Yague-Martinez, Nestor; Pinheiro, Muriel; Kim, Jun-Su; Vecchioli, Francesco; Minati, Federico; Costantini, Mario; Foumelis, Michael; Desnos, Yves-Louis

2017-04-01

The contribution focuses on the current status of the ESA study entitled "INSARAP Sentinel-1 Constellation Study" and investigates the interferometric performance of the S1A/S1B units. In particular, we refer to the Vesuvius/Campi Flegrei (Southern Italy) volcanic test site, where the continuous inflation (about 35 cm from 2011 to date) and the huge availability of ground-based geodetic data (continuous GPS - cGPS - leveling, tiltmetric, gravimetric, etc.) from the INGV-Osservatorio Vesuviano monitoring networks have allowed to get a clear deformation signal, besides the comparison between S1A/S1B and geodetic data. In this regard, the integration between InSAR and geodetic measurements is crucial for a continuous and extended monitoring of such an active volcanic area, as InSAR investigations allow to get an information on wide areas, whereas permanent networks (e.g., cGPS), allow to provide a continuous information complementing InSAR, which is limited by its revisiting time. Comparisons between S1 constellation data and geodetic measurements, with a particular focus on cGPS, will be presented, exploiting both LOS and inverted (E-W and vertical inversion) InSAR data starting from October, 2014. In addition, as a next step we are planning to model the deformation source of the area by exploiting the S1 time series results. Ultimately, very encouraging results suggest for a continuation of this activity also for the future, showing the great potential of S1 constellation data for monitoring active volcanic areas and, in general, to retrieve a very high quality deformation signal.

Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Avila-Olivera, Jorge A.; Instituto de Investigaciones Metalurgicas, Universidad Michoacana de San Nicolas de Hidalgo, C.U., 58030 Morelia, Michoacan; Farina, Paolo

2008-05-07

In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults 'Oriente' and 'Poniente'. At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system 'Taxco-San Miguel de Allende'. In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create amore » map of the current phreatic level decline in city with the information of deep wells and using the 'kriging' method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults 'Oriente' and 'Universidad Pedagogica' are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year.« less

Monitoring of Building Construction by 4D Change Detection Using Multi-temporal SAR Images

NASA Astrophysics Data System (ADS)

Yang, C. H.; Pang, Y.; Soergel, U.

2017-05-01

Monitoring urban changes is important for city management, urban planning, updating of cadastral map, etc. In contrast to conventional field surveys, which are usually expensive and slow, remote sensing techniques are fast and cost-effective alternatives. Spaceborne synthetic aperture radar (SAR) sensors provide radar images captured rapidly over vast areas at fine spatiotemporal resolution. In addition, the active microwave sensors are capable of day-and-night vision and independent of weather conditions. These advantages make multi-temporal SAR images suitable for scene monitoring. Persistent scatterer interferometry (PSI) detects and analyses PS points, which are characterized by strong, stable, and coherent radar signals throughout a SAR image sequence and can be regarded as substructures of buildings in built-up cities. Attributes of PS points, for example, deformation velocities, are derived and used for further analysis. Based on PSI, a 4D change detection technique has been developed to detect disappearance and emergence of PS points (3D) at specific times (1D). In this paper, we apply this 4D technique to the centre of Berlin, Germany, to investigate its feasibility and application for construction monitoring. The aims of the three case studies are to monitor construction progress, business districts, and single buildings, respectively. The disappearing and emerging substructures of the buildings are successfully recognized along with their occurrence times. The changed substructures are then clustered into single construction segments based on DBSCAN clustering and α-shape outlining for object-based analysis. Compared with the ground truth, these spatiotemporal results have proven able to provide more detailed information for construction monitoring.

12 CFR 563.180 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2013 CFR

2013-01-01

....C. 1813(u) and 1818(b)(9)). (iii) SAR means a Suspicious Activity Report. (3) SARs required. A... action. (11) Obtaining SARs. A savings association or service corporation may obtain SARs and the...) Confidentiality of SARs. A SAR, and any information that would reveal the existence of a SAR, are confidential...

12 CFR 563.180 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2014 CFR

2014-01-01

....C. 1813(u) and 1818(b)(9)). (iii) SAR means a Suspicious Activity Report. (3) SARs required. A... action. (11) Obtaining SARs. A savings association or service corporation may obtain SARs and the...) Confidentiality of SARs. A SAR, and any information that would reveal the existence of a SAR, are confidential...

12 CFR 563.180 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2012 CFR

2012-01-01

....C. 1813(u) and 1818(b)(9)). (iii) SAR means a Suspicious Activity Report. (3) SARs required. A... action. (11) Obtaining SARs. A savings association or service corporation may obtain SARs and the...) Confidentiality of SARs. A SAR, and any information that would reveal the existence of a SAR, are confidential...

Space Radar Image of West Texas - SAR scan

NASA Technical Reports Server (NTRS)

1999-01-01

This radar image of the Midland/Odessa region of West Texas, demonstrates an experimental technique, called ScanSAR, that allows scientists to rapidly image large areas of the Earth's surface. The large image covers an area 245 kilometers by 225 kilometers (152 miles by 139 miles). It was obtained by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) flying aboard the space shuttle Endeavour on October 5, 1994. The smaller inset image is a standard SIR-C image showing a portion of the same area, 100 kilometers by 57 kilometers (62 miles by 35 miles) and was taken during the first flight of SIR-C on April 14, 1994. The bright spots on the right side of the image are the cities of Odessa (left) and Midland (right), Texas. The Pecos River runs from the top center to the bottom center of the image. Along the left side of the image are, from top to bottom, parts of the Guadalupe, Davis and Santiago Mountains. North is toward the upper right. Unlike conventional radar imaging, in which a radar continuously illuminates a single ground swath as the space shuttle passes over the terrain, a Scansar radar illuminates several adjacent ground swaths almost simultaneously, by 'scanning' the radar beam across a large area in a rapid sequence. The adjacent swaths, typically about 50 km (31 miles) wide, are then merged during ground processing to produce a single large scene. Illumination for this L-band scene is from the top of the image. The beams were scanned from the top of the scene to the bottom, as the shuttle flew from left to right. This scene was acquired in about 30 seconds. A normal SIR-C image is acquired in about 13 seconds. The ScanSAR mode will likely be used on future radar sensors to construct regional and possibly global radar images and topographic maps. The ScanSAR processor is being designed for 1996 implementation at NASA's Alaska SAR Facility, located at the University of Alaska Fairbanks, and will produce digital images from the forthcoming Canadian RADARSAT satellite. Spaceborne Imaging Radar-C and X-band Synthetic Aperture Radar (SIR-C/X-SAR) is part of NASA's Mission to Planet Earth. The radars illuminate Earth with microwaves, allowing detailed observations at any time, regardless of weather or sunlight conditions. SIR-C/X-SAR uses three microwave wavelengths: L-band (24 cm), C-band (6 cm) and X-band (3 cm). The multi-frequency data will be used by the international scientific community to better understand the global environment and how it is changing. The SIR-C/X-SAR data, complemented by aircraft and ground studies, will give scientists clearer insights into those environmental changes which are caused by nature and those changes which are induced by human activity. SIR-C was developed by NASA's Jet Propulsion Laboratory. X-SAR was developed by the Dornier and Alenia Spazio companies for the German space agency, Deutsche Agentur fuer Raumfahrtangelegenheiten (DARA), and the Italian space agency, Agenzia Spaziale Italiana (ASI), with the Deutsche Forschungsanstalt fuer Luft und Raumfahrt e.v.(DLR), the major partner in science, operations, and data processing of X-SAR.

SWIFT Obervations in the Sea State DRI

DTIC Science & Technology

2018-02-28

arctic-autumn , 98 (2017). [published, refereed] • Ardhuin et al, Measuring ocean waves in sea ice using SAR imagery: A quasi -deterministic approach...Graber, H. Shen, J. Gemmrich, S. Lehner, B. Holt, and T. Williams, Science and Experiment Plan: Sea State and Boundary Layer Physics of the...live along the Arctic coastline and experience climate change firsthand. Our results will be published in a special issue (http

Department of the Navy Transformation Plan FY 2014-2016

DTIC Science & Technology

2014-01-01

SUPPLEMENTARY NOTES 14. ABSTRACT 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF...with the competing realities of shrinking defense budgets and rising maritime security challenges. Throughout our history, the Navy and Marine...DON continues to support alternative energy efforts, realizing that energy independence is vital to our national security and the safety of our

Inter-comparison of hydrological model simulations with dense time series of SAR-derived soil moisture maps

NASA Astrophysics Data System (ADS)

Iacobellis, V.; Gioia, A.; Milella, P.; Satalino, G.; Balenzano, A.; Mattia, F.

2012-04-01

Over the last years, a vast number of experimental and theoretical studies has widely demonstrated the sensitivity of SAR data to soil moisture content, however, operational services integrating SAR measurements into land process models are not yet available. Important progresses in this field are expected, on the one hand, from SAR missions characterized by a short revisiting time, such as the COSMO-SkyMed or the forthcoming Sentinel-1 and ALOS-2 missions, on the other hand, from a strong effort in implementing hydrological models able to reproduce the dynamic of soil moisture content of the top layer (5 cm depth) of soil. With this latter purpose, we used the DREAM model [Manfreda et al., 2005], realized in a GIS-based approach, that explicitly takes into account the spatial heterogeneity of hydrological processes. The DREAM model carries out continuous hydrological simulations using the daily and the hourly scales. The distinctive feature of the model, which consists of evaluating the lateral flow through a water content redistribution weighted by the topographic index, was preserved. The latter provided the basis for the nested implementation of the Richard equation which has been used for evaluating vertical flows in the top soil layer (5cm).The Richard routine exploits the numerical solution proposed by Simunek et al. [2009] and runs, for each cell of the river basin, in a sub-module of 60 minutes with a vertical (i.e. depth) and temporal resolution of 1 cm and 1 s, respectively. The model was applied to the portion of the Celone at Foggia San Severo river basin downstream the San Giusto Dam, which is a tributary of the Candelaro river, in Puglia region (Southern Italy). Over this area quasi-dense time series of ALOS/PALSAR ScanSAR WB1 and COSMO-SkyMedStripMap images were acquired in 2007 and 2010, respectively. The SAR data have been used to derive time-series of soil moisture maps by means of the SMOSAR software developed for Sentinel-1 data [Balenzano et al., 2011; Mattia et al., 2011; Balenzano et al., 2012] and adapted to the X- [Mattia et al., 2012] and L-band [Satalino et al., 2010]. First results are promising, showing that the model is able to reproduce the general trend and has a good sensitivity to rainfall inputs. Such a kind of results open wide perspectives for model calibration/validation with external data as well as for assessing the proposed modelling structure, providing strong enhancements in terms of model scientific validation [e.g. Biondi et al. 2011]. ACKNOWLEDGEMENT The research in this paper is supported by the Italian Space Agency under contract n. I/051/09/0. COSMO-SkyMed data were provided by ©ASI in the framework of ©CSK AO 2161,PALSAR data were supplied in the framework of JAXA RA 13 & ESA ALOS ADEN AO 3597.

Motion of David Glacier in East Antarctica Observed by COSMO-SkyMed Differential SAR Interferometry

NASA Astrophysics Data System (ADS)

Han, H.; Lee, H.

2011-12-01

David glacier, located in Victoria Land, East Antarctica (75°20'S, 161°15'E), is an outlet glacier of 13 km width near the grounding line and 50 km long from the source to the grounding line. David glacier flows into Ross Sea forming Drygalski Ice Tongue, 100 km long and 23 km wide. In this study, we extracted a surface displacement map of David by applying differential SAR interferometry (DInSAR) to one-day tandem pairs obtained from COSMO-SkyMed satellites on April 28-29 (descending orbit) and May 5-6 (ascending orbit), 2011, respectively. Terra ASTER global digital elevation model (GDEM) is used to remove the topographic effect from the COSMO-SkyMed interferograms. David glacier showed maximum displacement of 35 cm during April 28-29 and 20 cm during May 5-6 in the direction of radar line of sight. The glacier can be divided into several blocks by the disparities of displacement between the different sliding zone. Surface displacement map contains errors originated from orbit data, atmospheric conditions, DEM error. GDEM is generated from the ASTER optical images acquired from 2000 to 2008. It has the vertical accuracy of about 20 m at 95% confidence with the 30 m of horizontal posting. The accuracy of GDEM reduces when cloud cover is included in the ASTER image. Particularly in the snow and ice area, GDEM is inaccurate due to whiteout effect during stereo matching. The inaccuracy of GDEM could be a reason of the observed glacier motion in the opposite direction of gravity. This problem can be solved by using TanDEM-X DEM. Bistatic acquisition of SAR images from the constellation of TerraSAR-X and TanDEM-X will generate a global DEM with the vertical accuracy better than 2 m and the horizontal posting of 12 m. We plan to perform DInSAR of COSMO-SkyMed one-day tandem pairs again when the high-accuracy TanDEM-X DEM is available in the near future. As a conclusion, we could analyze the displacement of David glacier in East Antarctica. The glacier showed very fast motion forming a block of streamlines with different flow velocity. For more accurate analysis, we will use TanDEM-X DEM to perform the DInSAR. The flow characteristics, ice mass balance, ice discharge rate of David glacier remains as an ongoing research.

Studies of ice sheet hydrology using SAR

NASA Technical Reports Server (NTRS)

Bindschadler, R. A.; Vornberger, P. L.

1989-01-01

Analysis of SAR data of the Greenland ice sheet in summer and winter suggest the use of SAR to monitor the temporal hydrology of ice sheets. Comparisons of each SAR data set with summer Landsat TM imagery show an areal-positive correlation with summer SAR data and a negative correlation with winter SAR data. It is proposed that the summer SAR data are most sensitive to the variable concentrations of free water in the surface snow and that the winter SAR data indicate variations in snow grain size.

The lessons of SARS in Hong Kong.

PubMed

Lai, Thomas Sik To; Yu, Wai Cho

2010-02-01

Severe acute respiratory syndrome (SARS) is a novel coronavirus infection which broke out in Hong Kong in March 2003. Princess Margaret Hospital was designated to manage this new, mysterious and serious disease. Healthcare workers had to work under extremely stressful and often risky conditions to care for patients. Despite manpower and equipment reinforcements, staff infection occurred as a result of bodily exhaustion, working in an unfamiliar environment and lapses in infection control. Patients suffered even more, not only due to physical discomfort, but also because of the fear of isolation and death away from family and friends. Health authorities learnt their lessons in the outbreak and formulated emergency plans for future infectious disease epidemics. The healthcare infrastructure has been examined and upgraded with regard to intensive care capacity, infection control measures, professional training, manpower deployment, staff facilities, and stockpiling of drugs and personal protective equipment.

The Staphylococcus aureus protein-coding gene gdpS modulates sarS expression via mRNA-mRNA interaction.

PubMed

Chen, Chuan; Zhang, Xu; Shang, Fei; Sun, Haipeng; Sun, Baolin; Xue, Ting

2015-08-01

Staphylococcus aureus is an important Gram-positive pathogen responsible for numerous diseases ranging from localized skin infections to life-threatening systemic infections. The virulence of S. aureus is essentially determined by a wide spectrum of factors, including cell wall-associated proteins and secreted toxins that are precisely controlled in response to environmental changes. GGDEF domain protein from Staphylococcus (GdpS) is the only conserved staphylococcal GGDEF domain protein that is involved not in c-di-GMP synthesis but in the virulence regulation of S. aureus NCTC8325. Our previous study showed that the inactivation of gdpS generates an extensive change of virulence factors together with, in particular, a major Spa (protein A) surface protein. As reported, sarS is a direct positive regulator of spa. The decreased transcript levels of sarS in the gdpS mutant compared with the parental NCTC8325 strain suggest that gdpS affects spa through interaction with sarS. In this study, site mutation and complementary experiments showed that the translation product of gdpS was not involved in the regulation of transcript levels of sarS. We found that gdpS functioned through direct RNA-RNA base pairing with the 5' untranslated region (5'UTR) of sarS mRNA and that a putative 18-nucleotide region played a significant role in the regulatory process. Furthermore, the mRNA half-life analysis of sarS in the gdpS mutant showed that gdpS positively regulates the mRNA levels of sarS by contributing to the stabilization of sarS mRNA, suggesting that gdpS mRNA may regulate spa expression in an RNA-dependent pathway. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Waveform Synthesizer For Imaging And Ranging Applications

DOEpatents

DUDLEY, PETER A.; [et al

2004-11-30

Frequency dependent corrections are provided for quadrature imbalance. An operational procedure filters imbalance effects without prior calibration or equalization. Waveform generation can be adjusted/corrected in a synthetic aperture radar system (SAR), where a rolling phase shift is applied to the SAR's QDWS signal where it is demodulated in a receiver; unwanted energies, such as imbalance energy, are separated from a desired signal in Doppler; the separated energy is filtered from the receiver leaving the desired signal; and the separated energy in the receiver is measured to determine the degree of imbalance that is represented by it. Calibration methods can also be implemented into synthesis. The degree of quadrature imbalance can be used to determine calibration values that can then be provided as compensation for frequency dependent errors in components, such as the QDWS and SSB mixer, affecting quadrature signal quality.

Research on Synthetic Aperture Radar Processing for the Spaceborne Sliding Spotlight Mode.

PubMed

Shen, Shijian; Nie, Xin; Zhang, Xinggan

2018-02-03

Gaofen-3 (GF-3) is China' first C-band multi-polarization synthetic aperture radar (SAR) satellite, which also provides the sliding spotlight mode for the first time. Sliding-spotlight mode is a novel mode to realize imaging with not only high resolution, but also wide swath. Several key technologies for sliding spotlight mode in spaceborne SAR with high resolution are investigated in this paper, mainly including the imaging parameters, the methods of velocity estimation and ambiguity elimination, and the imaging algorithms. Based on the chosen Convolution BackProjection (CBP) and PFA (Polar Format Algorithm) imaging algorithms, a fast implementation method of CBP and a modified PFA method suitable for sliding spotlight mode are proposed, and the processing flows are derived in detail. Finally, the algorithms are validated by simulations and measured data.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wahl, Daniel E.; Yocky, David A.; Jakowatz, Jr., Charles V.

In previous research, two-pass repeat-geometry synthetic aperture radar (SAR) coherent change detection (CCD) predominantly utilized the sample degree of coherence as a measure of the temporal change occurring between two complex-valued image collects. Previous coherence-based CCD approaches tend to show temporal change when there is none in areas of the image that have a low clutter-to-noise power ratio. Instead of employing the sample coherence magnitude as a change metric, in this paper, we derive a new maximum-likelihood (ML) temporal change estimate—the complex reflectance change detection (CRCD) metric to be used for SAR coherent temporal change detection. The new CRCD estimatormore » is a surprisingly simple expression, easy to implement, and optimal in the ML sense. As a result, this new estimate produces improved results in the coherent pair collects that we have tested.« less

Pandemic and public health controls: toward an equitable compensation system.

PubMed

Ly, Theresa; Selgelid, M J; Kerridge, I

2007-10-01

There is increasing global concern about the potential impact of pandemic infections, including influenza, SARS and bioterrorist attacks involving infectious diseases. Many countries have prepared plans for responding to a major pandemic. In Australia, the Federal and State pandemic plans include measures such as contact tracing, ensuring availability of antimicrobials, quarantine and social distancing. Many of these measures would involve severe restrictions on individual citizens and small businesses. Issues of compensation for cooperation and compliance with pandemic plans need to be addressed in policy discussion. The instrumental benefits of compensation in the event of a pandemic have not been sufficiently recognised. Greater attention paid now to mechanisms to compensate individual and business costs associated with compliance would increase trust in government pandemic plans, encourage compliance and reduce the health and economic impact of a pandemic.

Contribution of L-band SAR to systematic global mangrove monitoring

Treesearch

Richard Lucas; Lias-Maria Rebelo; Lola Fatoyinbo; Ake Rosenqvist; Takuya Itoh; Masanobu Shimada; Marc Simard; Pedro Walfir Souza-Filho; Nathan Thomas; Carl Trettin; Arnon Accad; Joao Carreiras; Lammert Hilarides

2014-01-01

Information on the status of and changes in mangroves is required for national and international policy development, implementation and evaluation. To support these requirements, a component of the Japan Aerospace Exploration Agency’s (JAXA) Kyoto and Carbon (K&C) initiative has been to design and develop capability for a Global Mangrove Watch (GMW) that routinely...

Chimeric severe acute respiratory syndrome coronavirus (SARS-CoV) S glycoprotein and influenza matrix 1 efficiently form virus-like particles (VLPs) that protect mice against challenge with SARS-CoV

PubMed Central

Liu, Ye V.; Massare, Michael J.; Barnard, Dale L.; Kort, Thomas; Nathan, Margret; Wang, Lei; Smith, Gale

2011-01-01

SARS-CoV was the cause of the global pandemic in 2003 that infected over 8000 people in 8 months. Vaccines against SARS are still not available. We developed a novel method to produce high levels of a recombinant SARS virus-like particles (VLPs) vaccine containing the SARS spike (S) protein and the influenza M1 protein using the baculovirus insect cell expression system. These chimeric SARS VLPs have a similar size and morphology to the wild type SARS-CoV. We tested the immunogenicity and protective efficacy of purified chimeric SARS VLPs and full length SARS S protein vaccines in a mouse lethal challenge model. The SARS VLP vaccine, containing 0.8 μg of SARS S protein, completely protected mice from death when administered intramuscular (IM) or intranasal (IN) routes in the absence of an adjuvant. Likewise, the SARS VLP vaccine, containing 4 μg of S protein without adjuvant, reduced lung virus titer to below detectable level, protected mice from weight loss, and elicited a high level of neutralizing antibodies against SARS-CoV. Sf9 cell-produced full length purified SARS S protein was also an effective vaccine against SARS-CoV but only when co-administered IM with aluminum hydroxide. SARS-CoV VLPs are highly immunogenic and induce neutralizing antibodies and provide protection against lethal challenge. Sf9 cell-based VLP vaccines are a potential tool to provide protection against novel pandemic agents. PMID:21762752

What to Do Until the Money Runs Out: A Refinement Framework for Cognitive Engineering in the Real World

NASA Technical Reports Server (NTRS)

Shafto, Michael G.; Remington, Roger W.; Trimble, Jay W.

1994-01-01

A case study is presented to illustrate some of the problems of applying cognitive science to complex human-machine systems. Disregard for facts about human cognition often undermines the safety, reliability, and cost-effectiveness of complex systems. Yet single-point methods (for example, better user-interface design), whether rooted in computer science or in experimental psychology, fall far short of addressing systems-level problems in a timely way using realistic resources. A model-based methodology is proposed for organizing and prioritizing the cognitive engineering effort, focusing appropriate expertise on major problems first, then moving to more sophisticated refinements if time and resources permit. This case study is based on a collaborative effort between the Human Factors Division at NASA-Ames and the Spaceborne Imaging Radar SIR-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) Project at the Jet Propulsion Laboratory (JPL), California institute of Technology. The first SIR-C/X-SAR Shuttle mission flew successfully in April, 1994. A series of such missions is planned to provide radar data to study Earth's ecosystems, climatic and geological processes, hydrologic cycle, and ocean circulation. In addition to JPL and NASA personnel, the SIR-C/X-SAR operations team included Scientists and engineers from the German and Italian space agencies.

Impact of a viral respiratory epidemic on the practice of medicine and rehabilitation: severe acute respiratory syndrome.

PubMed

Lim, Peter A; Ng, Yee Sien; Tay, Boon Keng

2004-08-01

Severe acute respiratory syndrome (SARS) is a new respiratory viral epidemic that originated in China but has affected many parts of the world, with devastating impact on economies and the practice of medicine and rehabilitation. A novel coronavirus has been implicated, with transmission through respiratory droplets. Rehabilitation was significantly affected by SARS, because strict infection control measures run counter to principles such as multidisciplinary interactions, patients encouraging and learning from each other, and close physical contact during therapy. Immunocompromised patients who may silently carry SARS are common in rehabilitation and include those with renal failure, diabetes, and cancer. Routine procedures such as management of feces and respiratory secretions (eg, airway suctioning, tracheotomy care) have been classified as high risk. Personal protection equipment presented not only a physical but also a psychologic barrier to therapeutic human contact. Visitor restriction to decrease chances of disease transmission are particularly difficult for long-staying rehabilitation patients. At the height of the epidemic, curtailment of patient movement stopped all transfers for rehabilitation, and physiatrists had to function as general internists. Our experiences strongly suggest that rehabilitation institutions should have emergency preparedness plans because such epidemics may recur, whether as a result of nature or of bioterrorism.

Medical Support for Aircraft Disaster Search and Recovery Operations at Sea: the RSN Experience.

PubMed

Teo, Kok Ann Colin; Chong, Tse Feng Gabriel; Liow, Min Han Lincoln; Tang, Kong Choong

2016-06-01

The maritime environment presents a unique set of challenges to search and recovery (SAR) operations. There is a paucity of information available to guide provision of medical support for SAR operations for aircraft disasters at sea. The Republic of Singapore Navy (RSN) took part in two such SAR operations in 2014 which showcased the value of a military organization in these operations. Key considerations in medical support for similar operations include the resultant casualty profile and challenges specific to the maritime environment, such as large distances of area of operations from land, variable sea states, and space limitations. Medical support planning can be approached using well-established disaster management life cycle phases of preparedness, mitigation, response, and recovery, which all are described in detail. This includes key areas of dedicated training and exercises, force protection, availability of air assets and chamber support, psychological care, and the forensic handling of human remains. Relevant lessons learned by RSN from the Air Asia QZ8501 search operation are also included in the description of these key areas. Teo KAC , Chong TFG , Liow MHL , Tang KC . Medical support for aircraft disaster search and recovery operations at sea: the RSN experience. Prehosp Disaster Med. 2016; 31(3):294-299.

SAR matrices: automated extraction of information-rich SAR tables from large compound data sets.

PubMed

Wassermann, Anne Mai; Haebel, Peter; Weskamp, Nils; Bajorath, Jürgen

2012-07-23

We introduce the SAR matrix data structure that is designed to elucidate SAR patterns produced by groups of structurally related active compounds, which are extracted from large data sets. SAR matrices are systematically generated and sorted on the basis of SAR information content. Matrix generation is computationally efficient and enables processing of large compound sets. The matrix format is reminiscent of SAR tables, and SAR patterns revealed by different categories of matrices are easily interpretable. The structural organization underlying matrix formation is more flexible than standard R-group decomposition schemes. Hence, the resulting matrices capture SAR information in a comprehensive manner.

Influenza A (H1N1-2009) pandemic in Singapore--public health control measures implemented and lessons learnt.

PubMed

Tay, Joanne; Ng, Yeuk Fan; Cutter, Jeffery L; James, Lyn

2010-04-01

We describe the public health control measures implemented in Singapore to limit the spread of influenza A (H1N1-2009) and mitigate its social effects. We also discuss the key learning points from this experience. Singapore's public health control measures were broadly divided into 2 phases: containment and mitigation. Containment strategies included the triage of febrile patients at frontline healthcare settings, admission and isolation of confirmed cases, mandatory Quarantine Orders (QO) for close contacts, and temperature screening at border entry points. After sustained community transmission became established, containment shifted to mitigation. Hospitals only admitted H1N1-2009 cases based on clinical indications, not for isolation. Mild cases were managed in the community. Contact tracing and QOs tapered off, and border temperature screening ended. The 5 key lessons learnt were: (1) Be prepared, but retain flexibility in implementing control measures; (2) Surveillance, good scientific information and operational research can increase a system's ability to manage risk during a public health crisis; (3) Integrated systems-level responses are essential for a coherent public health response; (4) Effective handling of manpower surges requires creative strategies; and (5) Communication must be strategic, timely, concise and clear. Singapore's effective response to the H1N1-2009 pandemic, founded on experience in managing the 2003 SARS epidemic, was a whole-of-government approach towards pandemic preparedness planning. Documenting the measures taken and lessons learnt provides a learning opportunity for both doctors and policy makers, and can help fortify Singapore's ability to respond to future major disease outbreaks.

Long-Term Monitoring of Water Dynamics in the Sahel Region Using the Multi-Sar

NASA Astrophysics Data System (ADS)

Bertram, A.; Wendleder, A.; Schmitt, A.; Huber, M.

2016-06-01

Fresh water is a scarce resource in the West-African Sahel region, seasonally influenced by droughts and floods. Particularly in terms of climate change, the importance of wetlands increases for flora, fauna, human population, agriculture, livestock and fishery. Hence, access to open water is a key factor. Long-term monitoring of water dynamics is of great importance, especially with regard to the spatio-temporal extend of wetlands and drylands. It can predict future trends and facilitate the development of adequate management strategies. Lake Tabalak, a Ramsar wetland of international importance, is one of the most significant ponds in Niger and a refuge for waterbirds. Nevertheless, human population growth increased the pressure on this ecosystem, which is now degrading for all uses. The main objective of the study is a long-term monitoring of the Lake Tabalak's water dynamics to delineate permanent and seasonal water bodies, using weather- and daytime-independent multi-sensor and multi-temporal Synthetic Aperture Radar (SAR) data available for the study area. Data of the following sensors from 1993 until 2016 are used: Sentinel-1A, TerraSARX, ALOS PALSAR-1/2, Envisat ASAR, RADARSAT-1/2, and ERS-1/2. All SAR data are processed with the Multi-SAR-System, unifying the different characteristics of all above mentioned sensors in terms of geometric, radiometric and polarimetric resolution to a consistent format. The polarimetric representation in Kennaugh elements allows fusing single-polarized data acquired by older sensors with multi-polarized data acquired by current sensors. The TANH-normalization guarantees a consistent and therefore comparable description in a closed data range in terms of radiometry. The geometric aspect is solved by projecting all images to an earth-fixed coordinate system correcting the brightness by the help of the incidence angle. The elevation model used in the geocoding step is the novel global model produced by the TanDEM-X satellite mission. The advantage of the Multi-SAR-System is that it comprises ortho-rectification, radiometric enhancement, normalization and Kennaugh decomposition, independent from sensors, modes, polarizations or acquisition date of SAR data. In addition, optical satellite data can be included as well, to fill gaps where SAR data are missing due to the special normalization scheme. This kind of pre-processing is exclusively implemented at the Earth Observation Center of the German Aerospace Center in Oberpfaffenhofen, Germany. Therefore, the dynamic change of the open water of the Lake Tabalak could be classified over dry and rainy seasons and years, using different SAR data. The study provides a unique database and contributes to a better understanding of wetland systems in the Sahel region influenced by human pressure and climate change.

Monitoring of land subsidence in Ravenna Municipality using two different DInSAR techniques: comparison and discussion of the results.

NASA Astrophysics Data System (ADS)

Fiaschi, Simone; Di Martire, Diego; Tessitore, Serena; Achilli, Vladimiro; Ahmed, Ahmed; Borgstrom, Sven; Calcaterra, Domenico; Fabris, Massimo; Ramondini, Massimo; Serpelloni, Enrico; Siniscalchi, Valeria; Floris, Mario

2015-04-01

Land subsidence affecting the Ravenna Municipality (Emilia Romagna Region, NE Italy) is one of the best example on how the exploitation of natural resources can affect the environment and the territory. In fact, the pumping of groundwater and the extraction of gas from both on and off-shore reservoirs, started in the 1950s, have caused a strong land subsidence affecting most of the Emilia Romagna territory but in particular the Adriatic Sea coastline near Ravenna. In such area the current subsidence rate, even if lower than in the past, can reach the -2cm/y. Local Authorities have monitored this phenomenon over the years with different techniques: spirit levelling, GPS surveys and, more recently, Interferometric Synthetic Aperture Radar (InSAR) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with two different DInSAR techniques applied to the study of the land subsidence in the Ravenna territory: the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques. The SBAS works on SARscape software and is based on the Berardino et al., 2002 algorithm. This technique relies on the combination of differential interferograms created from stacks of SAR image pairs that have small temporal and perpendicular baselines. Thanks to the application of several interferograms for every single image, it is possible to obtain high spatial coherence, high data density and more effective error reduction. This allows us to obtain mean velocity maps with good data density even over non-urbanized territories. For the CPT we used the SUBsoft processor based on the algorithm implemented by Mora et al., 2003. CPT is able to extract from a stack of differential interferograms the deformation evolution over wide areas during large time spans. The processing scheme is composed of three main steps: a) the generation of the best interferogram set among all the available images of the zone under study; b) the selection of the pixels with reliable phase within the employed interferograms and, c) their phase analysis to calculate, as the main result, their deformation time series within the observation period. For this study, different SAR images have been used: 25 meters ground resolution ERS 1/2 (1992-2000) and ENVISAT (2003-2010), and 3 meters ground resolution TerraSAR-X (2012-2014). The results obtained for each stack of images with the two techniques are validated and compared with the C-GPS time series of more than three benchmarks stations. The aim is to test the two InSAR techniques in the monitoring of ground settlements in low urbanized territories. Furthermore, we have investigated the advantages (data accuracy and density) of using SAR images with higher ground resolution.

SARS Grid--an AG-based disease management and collaborative platform.

PubMed

Hung, Shu-Hui; Hung, Tsung-Chieh; Juang, Jer-Nan

2006-01-01

This paper describes the development of the NCHC's Severe Acute Respiratory Syndrome (SARS) Grid project-An Access Grid (AG)-based disease management and collaborative platform that allowed for SARS patient's medical data to be dynamically shared and discussed between hospitals and doctors using AG's video teleconferencing (VTC) capabilities. During the height of the SARS epidemic in Asia, SARS Grid and the SARShope website significantly curved the spread of SARS by helping doctors manage the in-hospital and in-home care of quarantined SARS patients through medical data exchange and the monitoring of the patient's symptoms. Now that the SARS epidemic has ended, the primary function of the SARS Grid project is that of a web-based informatics tool to increase pubic awareness of SARS and other epidemic diseases. Additionally, the SARS Grid project can be viewed and further studied as an outstanding model of epidemic disease prevention and/or containment.

The contribution of the Volcano Observations Work Package to the implementation of the European Plate Observing System

NASA Astrophysics Data System (ADS)

Puglisi, Giuseppe

2016-04-01

The overall aim of the implementation phase of European Plate Observing System (EPOS) is to make the integrated platform operational in order to guarantee seamless access to the data provided by the European Solid Earth communities. The Volcano Observations Work Package (WP11) contributes to this objective by implementing a Thematic Core Service (TCS) which is planned to give access to the data and services provided by the European Volcano Observatories (VO) and some Volcanological Research Institutions (VRI; such as university departments, laboratories, etc.). Both types are considered as national research infrastructures (RI) which the TCS will integrate. Currently, monitoring networks on European volcanoes consist of thousands of stations or sites where volcanological parameters are continuously or periodically measured. These sites are equipped with instruments for geophysical (seismic, geodetic, gravimetric, electromagnetic), geochemical (volcanic plumes, fumaroles, groundwater, rivers, soils), environmental observations (e.g. meteorological and air quality parameters), as well as various prototypal monitoring systems (e.g. Doppler radars, ground based SAR). Across Europe several laboratories provide sample characterization (rocks, gases, isotopes, etc.), quasi-continuous analysis of space-borne data (SAR, thermal imagery, SO2 and ash), as well as high-performance computing facilities. All these RIs provide high-quality information (observations) on the current status of European volcanoes and the geodynamic background of the surrounding areas. The implementation of the Volcano Observations TCS will address technical as well as managerial issues, both considering the current heterogeneous state-of-the-art of the volcanological research infrastructures in Europe. Indeed, the current arrangement of individual VO and VRI is considered too fragmented to be considered as a unique distributed infrastructure. Therefore, the main effort in the framework of the EPOS-IP is focused towards creating services aimed at providing an improved and more efficient access to the volcanological facilities and observations at active volcanoes. The fragmentation reflects in the heterogeneity of the technical solutions to provide the access and in the managerial issues, particularly in the data policies, governance structures and financial perspectives. Indeed, each research infrastructure currently adopts its own data policy (moreover, in some cases it is difficult to define a proper data policy), refers to different financial models and follows different organization. This is partly also due to the different formal commitments and mandates of VO and/or VRI within their own jurisdictions. Thus the main challenge of the WP11 in the framework of EPOS-IP is to overcome the current fragmentation and to strengthen the construction of the European volcanological community. Its current world-leading reputation is confirmed by the fact that three out of four Volcanic Supersites are located in Europe, are managed by European institutions and are studied by two EC-FP7 Projects (Futurevolc and MED-SUV).

Alternative synthetic aperture radar (SAR) modalities using a 1D dynamic metasurface antenna

NASA Astrophysics Data System (ADS)

Boyarsky, Michael; Sleasman, Timothy; Pulido-Mancera, Laura; Imani, Mohammadreza F.; Reynolds, Matthew S.; Smith, David R.

2017-05-01

Synthetic aperture radar (SAR) systems conventionally rely on mechanically-actuated reflector dishes or large phased arrays for generating steerable directive beams. While these systems have yielded high-resolution images, the hardware suffers from considerable weight, high cost, substantial power consumption, and moving parts. Since these disadvantages are particularly relevant in airborne and spaceborne systems, a flat, lightweight, and low-cost solution is a sought-after goal. Dynamic metasurface antennas have emerged as a recent technology for generating waveforms with desired characteristics. Metasurface antennas consist of an electrically-large waveguide loaded with numerous subwavelength radiators which selectively leak energy from a guided wave into free space to form various radiation patterns. By tuning each radiating element, we can modulate the aperture's overall radiation pattern to generate steered directive beams, without moving parts or phase shifters. Furthermore, by using established manufacturing methods, these apertures can be made to be lightweight, low-cost, and planar, while maintaining high performance. In addition to their hardware benefits, dynamic metasurfaces can leverage their dexterity and high switching speeds to enable alternative SAR modalities for improved performance. In this work, we briefly discuss how dynamic metasurfaces can conduct existing SAR modalities with similar performance as conventional systems from a significantly simpler hardware platform. We will also describe two additional modalities which may achieve improved performance as compared to traditional modalities. These modalities, enhanced resolution stripmap and diverse pattern stripmap, offer the ability to circumvent the trade-off between resolution and region-of-interest size that exists within stripmap and spotlight. Imaging results with a simulated dynamic metasurface verify the benefits of these modalities and a discussion of implementation considerations and noise effects is also included. Ultimately, the hardware gains coupled with the additional modalities well-suited to dynamic metasurface antennas has poised them to propel the SAR field forward and open the door to exciting opportunities.

InSAR MSBAS Time-Series Analysis of Induced Seismicity in Colorado and Oklahoma

NASA Astrophysics Data System (ADS)

Barba, M.; Tiampo, K. F.; Samsonov, S. V.

2016-12-01

Since 2009, the number of earthquakes in the central and eastern United States has dramatically increased from an average of 24 M ≥ 3 earthquakes a year (1973-2008) to an average of 193 M ≥ 3 earthquakes a year (2009-2014) (Ellsworth, 2013). Wastewater injection, the deep disposal of fluids, is considered to be the primary reason for this increase in seismicity rate (Weingarten et al., 2015). We use Interferometric Synthetic Aperture Radar (InSAR) to study four potential regions with injection induced seismicity: Greely, CO, Platteville, CO, Edmond, OK, and Jones, OK. Currently, Platteville is not seismically active; however, it serves as a baseline since its high-volume injection wells have the potential to induce future earthquakes. InSAR data complements seismic data by providing insight into the surface deformation potentially correlated with earthquake activity. To study the ground deformation associated with the induced seismicity and injection well activity, we develop full-resolution interferograms using raw radar data from Radarsat-1/2, ERS-1/2, Envisat, ALOS, and Sentinel-1. We pair the SAR images using the small perpendicular baseline approach (Berardino et al., 2002) to minimize spatial decorrelation. The paired SAR images are processed into interferograms using the JPL ISCE software (Gurrola et al., 2010). Using the MSBAS algorithm (Samsonov et al., 2013, Samsonov and d'Oreye, 2012) and the JPL GIAnT software (Agram et al., 2013), we construct a time-series of the cumulative surface displacement, integrating all interferograms for the region. To correlate the relationship between surface deformation and wastewater injection, we compare the well locations, depths, and injection rates with the spatial and temporal signature of the surface deformation before and after induced earthquakes, filling in the spatiotemporal gap lacking from seismicity. By monitoring the surface deformation for wells associated with past and current induced seismicity, we can implement measures to mitigate induced seismicity and its social and economic impact.

The Sentinel-3 Surface Topography Mission (S-3 STM): Level 2 SAR Ocean Retracker

NASA Astrophysics Data System (ADS)

Dinardo, S.; Lucas, B.; Benveniste, J.

2015-12-01

The SRAL Radar Altimeter, on board of the ESA Mission Sentinel-3 (S-3), has the capacity to operate either in the Pulse-Limited Mode (also known as LRM) or in the novel Synthetic Aperture Radar (SAR) mode. Thanks to the initial results from SAR Altimetry obtained exploiting CryoSat-2 data, lately the interest by the scientific community in this new technology has significantly increased and consequently the definition of accurate processing methodologies (along with validation strategies) has now assumed a capital importance. In this paper, we present the algorithm proposed to retrieve from S-3 STM SAR return waveforms the standard ocean geophysical parameters (ocean topography, wave height and sigma nought) and the validation results that have been so far achieved exploiting the CryoSat-2 data as well as the simulated data. The inversion method (retracking) to extract from the return waveform the geophysical information is a curve best-fitting scheme based on the bounded Levenberg-Marquardt Least-Squares Estimation Method (LEVMAR-LSE). The S-3 STM SAR Ocean retracking algorithm adopts, as return waveform’s model, the “SAMOSA” model [Ray et al, 2014], named after the R&D project SAMOSA (led by Satoc and funded by ESA), in which it has been initially developed. The SAMOSA model is a physically-based model that offers a complete description of a SAR Altimeter return waveform from ocean surface, expressed in the form of maps of reflected power in Delay-Doppler space (also known as stack) or expressed as multilooked echoes. SAMOSA is able to account for an elliptical antenna pattern, mispointing errors in roll and yaw, surface scattering pattern, non-linear ocean wave statistics and spherical Earth surface effects. In spite of its truly comprehensive character, the SAMOSA model comes with a compact analytical formulation expressed in term of Modified Bessel functions. The specifications of the retracking algorithm have been gathered in a technical document (DPM) and delivered as baseline for industrial implementation. For operational needs, thanks to the fine tuning of the fitting library parameters and the usage of look-up table for Bessel functions computation, the CPU execution time was accelerated over 100 times and made the execution in par with real time. In the course of the ESA-funded project CryoSat+ for Ocean (CP4O), new technical evolutions for the algorithm have been proposed (as usage of PTR width look up table and application of a stack masking). One of the main outcomes of the CP4O project was that, with these latest evolutions, the SAMOSA SAR retracking was giving equivalent results to CNES CPP retracking prototype, which was built with a totally different approach, which enforces the validation results. Work actually is underway to align the industrial implementation with the last new evolutions. Further, in order to test the algorithm with a dataset as realistic as possible, a set of simulated Test Data Set (generated by S-3 STM End-to-End Simulator) has been created by CLS following the specifications as described in a test data set requirements document drafted by ESA. In this work, we will show the baseline algorithm details, the evolutions, the impact of the evolutions and the results obtained processing the CryoSat-2 data and the simulated test data set.

12 CFR 21.11 - Suspicious Activity Report.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Activity Report. (c) SARs required. A national bank shall file a SAR with the appropriate Federal law... supervisory action. (j) Obtaining SARs. A national bank may obtain SARs and the Instructions from the appropriate OCC District Office listed in 12 CFR part 4. (k) Confidentiality of SARs. A SAR, and any...

12 CFR 21.11 - Suspicious Activity Report.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Activity Report. (c) SARs required. A national bank shall file a SAR with the appropriate Federal law... supervisory action. (j) Obtaining SARs. A national bank may obtain SARs and the Instructions from the appropriate OCC District Office listed in 12 CFR part 4. (k) Confidentiality of SARs. A SAR, and any...

Controlling Data Collection to Support SAR Image Rotation

DOEpatents

Doerry, Armin W.; Cordaro, J. Thomas; Burns, Bryan L.

2008-10-14

A desired rotation of a synthetic aperture radar (SAR) image can be facilitated by adjusting a SAR data collection operation based on the desired rotation. The SAR data collected by the adjusted SAR data collection operation can be efficiently exploited to form therefrom a SAR image having the desired rotational orientation.

Evaluation of the Potentials and Challenges of an Airborne InSAR System for Deformation Mapping: A Case Study over the Slumgullion Landslide

NASA Astrophysics Data System (ADS)

Cao, N.; Lee, H.; Zaugg, E.; Shrestha, R. L.; Carter, W. E.; Glennie, C. L.; Wang, G.; Lu, Z.; Diaz, J. C. F.

2016-12-01

Synthetic aperture radar (SAR) interferometry (InSAR) is a technique which uses two or more SAR images of the same area to estimate landscape topography or ground surface displacement. Differential InSAR (DInSAR) is capable of measuring ground displacements at the millimeter level, but a major drawback of traditional DInSAR is that only the deformation along the line-of-sight direction can be detected. Because most of the current spaceborne SAR systems have near-polar, sun-synchronous orbits, deformation measurements in the South-North direction are limited (except for polar regions). Compared with spaceborne SAR, airborne SAR systems have the advantages of flexible scanning geometry and revisit time, high spatial resolution, and no ionospheric distortion. In this study, we present a case study of the Slumgullion landslide conducted in July 2015 to assess an airborne SAR system known as ARTEMIS SlimSAR, which is a compact, modular, and multi-frequency radar system. The Slumgullion landslide, located in the San Juan Mountains near Lake City, Colorado is a long-term slow moving landslide that moves downhill continuously. For this study, the L-band SlimSAR was installed and data were collected on July 3, 7, and 10 and processed using the time-domain backprojection algorithm. GPS surveys and spaceborne DInSAR analysis using COSMO-SkyMed images were also conducted to verify the performance of the airborne SAR system. The airborne DInSAR results showed satisfying agreement with the GPS and spaceborne DInSAR results. The root mean square of the differences between the SlimSAR, and GPS and satellite derived velocities, were 0.6 mm/day, and 0.9 mm/day, respectively. A 3-D deformation map over Slumgullion landslide was generated, which displayed distinct correlation between the landslide motion and topography. This study also indicated that the primary source of the error for the SlimSAR system is the trajectory turbulences of the aircraft. The effect of the trajectory turbulences is analyzed and several possible solutions are proposed to improve the airborne SAR performance. In the long run, an improved airborne SAR system will open avenues for differential interferometry to be used in scientific studies and commercial applications previously prohibited by orbital constraints of spaceborne SAR.

Small baseline subsets approach of DInSAR for investigating land surface deformation along the high-speed railway

NASA Astrophysics Data System (ADS)

Rao, Xiong; Tang, Yunwei

2014-11-01

Land surface deformation evidently exists in a newly-built high-speed railway in the southeast of China. In this study, we utilize the Small BAseline Subsets (SBAS)-Differential Synthetic Aperture Radar Interferometry (DInSAR) technique to detect land surface deformation along the railway. In this work, 40 Cosmo-SkyMed satellite images were selected to analyze the spatial distribution and velocity of the deformation in study area. 88 pairs of image with high coherence were firstly chosen with an appropriate threshold. These images were used to deduce the deformation velocity map and the variation in time series. This result can provide information for orbit correctness and ground control point (GCP) selection in the following steps. Then, more pairs of image were selected to tighten the constraint in time dimension, and to improve the final result by decreasing the phase unwrapping error. 171 combinations of SAR pairs were ultimately selected. Reliable GCPs were re-selected according to the previously derived deformation velocity map. Orbital residuals error was rectified using these GCPs, and nonlinear deformation components were estimated. Therefore, a more accurate surface deformation velocity map was produced. Precise geodetic leveling work was implemented in the meantime. We compared the leveling result with the geocoding SBAS product using the nearest neighbour method. The mean error and standard deviation of the error were respectively 0.82 mm and 4.17 mm. This result demonstrates the effectiveness of DInSAR technique for monitoring land surface deformation, which can serve as a reliable decision for supporting highspeed railway project design, construction, operation and maintenance.

Impact of swine influenza and quarantine measures on patients and households during the H1N1/09 pandemic.

PubMed

Teh, Benjamin; Olsen, Karen; Black, Jim; Cheng, Allen C; Aboltins, Craig; Bull, Kirstin; Johnson, Paul D R; Grayson, M Lindsay; Torresi, Joseph

2012-04-01

To assess the secondary attack rates (SAR) and impact of the 2009 H1N1 epidemic in Melbourne, Victoria, Australia, and the measures implemented to control household transmission. Patients with polymerase chain reaction-confirmed influenza A and pandemic H1N1 (pH1N1) were identified from hospital and microbiology laboratory records and asked to take part in a retrospective survey. Information obtained included: the constellation of symptoms, contact history, secondary infection, and household information, including adherence and attitudes towards quarantine measures. The overall SAR of pH1N1 index patients was 30.6%, but a significantly lower SAR was noted with oseltamivir treatment (36.6% vs 22.8%, p < 0.05). The greatest reduction in SAR was observed when index patients aged 0-4 y received oseltamivir (83.3% vs 22.2%, p < 0.01). Quarantine was requested of 65.8% of patients and 92.8% self-reported adhering to recommendations. pH1N1 index patients, the number of median days bed-bound is 2.5 days, being unable or too sick to work for a median of 5.0 days, and lost a median of 7.0 days of work for reasons related to an influenza-like illness. The pH1N1 influenza pandemic had a significant clinical impact on households. Public health interventions such as oseltamivir treatment of index cases were beneficial in reducing secondary attack rates, whilst quarantine measures were found to have high rates of self-reported compliance, understanding, and acceptability.

Estimating Velocities of Glaciers Using Sentinel-1 SAR Imagery

NASA Astrophysics Data System (ADS)

Gens, R.; Arnoult, K., Jr.; Friedl, P.; Vijay, S.; Braun, M.; Meyer, F. J.; Gracheva, V.; Hogenson, K.

2017-12-01

In an international collaborative effort, software has been developed to estimate the velocities of glaciers by using Sentinel-1 Synthetic Aperture Radar (SAR) imagery. The technique, initially designed by the University of Erlangen-Nuremberg (FAU), has been previously used to quantify spatial and temporal variabilities in the velocities of surging glaciers in the Pakistan Karakoram. The software estimates surface velocities by first co-registering image pairs to sub-pixel precision and then by estimating local offsets based on cross-correlation. The Alaska Satellite Facility (ASF) at the University of Alaska Fairbanks (UAF) has modified the software to make it more robust and also capable of migration into the Amazon Cloud. Additionally, ASF has implemented a prototype that offers the glacier tracking processing flow as a subscription service as part of its Hybrid Pluggable Processing Pipeline (HyP3). Since the software is co-located with ASF's cloud-based Sentinel-1 archive, processing of large data volumes is now more efficient and cost effective. Velocity maps are estimated for Single Look Complex (SLC) SAR image pairs and a digital elevation model (DEM) of the local topography. A time series of these velocity maps then allows the long-term monitoring of these glaciers. Due to the all-weather capabilities and the dense coverage of Sentinel-1 data, the results are complementary to optically generated ones. Together with the products from the Global Land Ice Velocity Extraction project (GoLIVE) derived from Landsat 8 data, glacier speeds can be monitored more comprehensively. Examples from Sentinel-1 SAR-derived results are presented along with optical results for the same glaciers.

Space-Based Detection of Sinkhole Activity in Central Florida

NASA Astrophysics Data System (ADS)

Oliver-Cabrera, T.; Kruse, S.; Wdowinski, S.

2015-12-01

Central Florida's thick carbonate deposits and hydrological conditions have made the area prone to sinkhole development. Sinkhole collapse is a major geologic hazard in central Florida threatening human life and causing substantial damage to property. According to the Florida Senate report in 2010, between 2006-2010 total insurance claims due to sinkhole activity were around $200 million per year. Detecting sinkhole deformation before a collapse is a very difficult task, due to small or sometimes unnoticeable surface changes. Most techniques used to monitor sinkholes provide very localized information and cannot be implemented to study broad areas. This is the case of central Florida, where the active zone spans over hundreds of square-kilometers. In this study we use Interferometric Synthetic Aperture Radar (InSAR) observations acquired over several locations in central Florida to detect possible pre-collapse deformation. The study areas were selected because they have shown suspicious sinkhole behavior. One of the sites collapsed on March 2013 destroying a property and killing a man. To generate the InSAR results we use six datasets acquired by the TerraSAR-X and Cosmo-SkyMed satellites with various acquisition modes reflecting pixel resolutions between 25cm and 2m. Preliminary InSAR results show good coherence over constructed areas and low coherence in vegetated zones, justifying our analysis that focuses on the man-made structures. After full datasets will be acquired, a Persistent Scatterer Interferometry (PSI) time series analysis will be performed for detecting localized deformation at spatial scale of 1-5 meters. The project results will be verified using Ground Penetrating Radar.

78 FR 28776 - Approval and Promulgation of Implementation Plans; Georgia; State Implementation Plan...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-16

... Section of this Federal Register, EPA is approving the State's implementation plan revision as a direct... Promulgation of Implementation Plans; Georgia; State Implementation Plan Miscellaneous Revisions AGENCY... State Implementation Plan (SIP) submitted by the Georgia Environmental Protection Division to EPA in...

The "Volcano Observations" Thematic Core Service of the European Plate Observing System (EPOS): status of the implementation.

NASA Astrophysics Data System (ADS)

Puglisi, Giuseppe

2017-04-01

The European volcanological community contributes to implementation of European Plate Observing System (EPOS) by making operational an integrated platform to guarantee a seamless access to the data provided by the European Solid Earth communities. To achieve this objective, the Volcano Observations Work Package (WP11) will implement a Thematic Core Services (TCS) which is planned to give access to the data and services provided by the European Volcano Observatories (VO) and some Volcanological Research Institutions (VRI; as university departments, laboratories, etc.); both types are considered as national research infrastructures (RI) over which to build the TCS. Currently, the networks on European volcanoes consist of thousands of stations or sites where volcanological parameters are continuously or periodically measured. These sites are equipped with instruments for geophysical (seismic, geodetic, gravimetric, electromagnetic), geochemical (volcanic plumes, fumaroles, groundwater, rivers, soils), environmental observations (e.g. meteorological and air quality parameters), as well as various prototypal monitoring systems (e.g. Doppler radars, ground based SAR). In Europe also operate laboratories for sample analysis (rocks, gases, isotopes, etc.), and almost continuous analysis of space-borne data (SAR, thermal imagery, SO2 and ash), as well as high-performance computing centres. All these RIs provide high-quality information (observations) on the current status of European volcanoes and the geodynamic background of the surrounding areas. The implementation of the Volcano Observations TCS is addressing technical and management issues, both considering the current heterogeneous state of the art of the volcanological research infrastructures in Europe. Indeed, the frame of the VO and VRI is now too fragmented to be considered as a unique distributed infrastructure, thus the main effort planned in the frame of the EPOS-IP is focused to create services aimed at providing an improved and more efficient access to the volcanological facilities and observations on active volcanoes. The main gap to be overcame to facilitate the access to this valued information and to make this fragmented community into a unique infrastructure is concerning the heterogeneity in the technical solutions to provide the access. To tackle with this issue, WP11 launched an internal questionnaire to survey the current status of the services among the partners involved in the project. The technical heterogeneity reflects also in the management issues, and in particular in the data policies, governance structures and financial perspectives. Indeed, each research infrastructure currently adopts a own data policy (moreover, in some cases it is difficult to define a proper data policy), refers to different financial models and has different organization, also due to the different formal commitments of VO and/or VRI in own countries. Furthermore, to guarantee the sustainability of the TCS, a proper governance structure and financial model is under definition, with the twofold aim to guarantee the service provision and to represent the community. Thus the main challenging objective of the WP11 in the framework of EPOS-IP is to overcome the fragmentation and to strengthen the building of the European volcanological community which current worldwide high reputation is confirmed by the fact that three over four volcanic Supersites are located in Europe, managed by European institutions and were supported by EC through two EC-FP7 Projects (Futurevolc and MED-SUV).

Global Positioning System III (GPS III)

DTIC Science & Technology

2013-12-01

Galileo satellite navigation system signal, E1. L1C is also compatible with those signals planned for broadcast on Japan’s Quazi-Zenith Satellite...and Galileo constellations, further increasing the accuracy and availability of civil PNT solutions. GPS III December 2013 SAR April 16, 2014...vehicle- level core mate. The overall program continues to make progress on the GPS III Non-Flight Satellite Testbed (GNST), on SV01 development, and

Final Scientific/Technical Report for project “Geomechanical Monitoring for CO 2 Hub Storage: Production and Injection at Kevin Dome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daley, Thomas M.; Vasco, Don; Ajo-Franklin, Jonathan

After learning that the TDS value in the target injection formation at the Kevin Dome site is too low to qualify for an EPA Class VI CO2 injection permit, the BSCSP project was re-scoped such that injection of CO2 is no longer planned. With no injection planned, the Geomechanics project was closed. In this final report, we describe the objective and approach of the project as proposed, and the limited results obtained before stopping work. The objective of the proposed research was the development & validation of an integrated monitoring approach for quantifying the interactions between large-scale geological carbon storagemore » (GCS) and subsurface geomechanical state, particularly perturbations relevant to reservoir integrity such as fault reactivation and induced fracturing. In the short period of work before knowing the fate of the Kevin Dome project, we (1) researched designs for both the proposed InSAR corner reflectors as well as the near-surface 3C seismic stations; (2) developed preliminary elastic geomechanical models; (3) developed a second generation deformation prediction for the BSCSP Kevin Dome injection site; and (4) completed a preliminary map of InSAR monuments and shallow MEQ wells in the vicinity of the BSCSP injection pad.« less

12 CFR 21.11 - Suspicious Activity Report.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Activity Report on the form prescribed by the OCC. (c) SARs required. A national bank shall file a SAR with... supervisory action. (j) Obtaining SARs. A national bank may obtain SARs and the Instructions from the appropriate OCC District Office listed in 12 CFR part 4. (k) Confidentiality of SARs. SARs are confidential...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Graham, E-mail: gsimmons@bloodsystems.or; Bertram, Stephanie; Glowacka, Ilona

Severe acute respiratory syndrome coronavirus (SARS-CoV) poses a considerable threat to human health. Activation of the viral spike (S)-protein by host cell proteases is essential for viral infectivity. However, the cleavage sites in SARS-S and the protease(s) activating SARS-S are incompletely defined. We found that R667 was dispensable for SARS-S-driven virus-cell fusion and for SARS-S-activation by trypsin and cathepsin L in a virus-virus fusion assay. Mutation T760R, which optimizes the minimal furin consensus motif 758-RXXR-762, and furin overexpression augmented SARS-S activity, but did not result in detectable SARS-S cleavage. Finally, SARS-S-driven cell-cell fusion was independent of cathepsin L, a proteasemore » essential for virus-cell fusion. Instead, a so far unknown leupeptin-sensitive host cell protease activated cellular SARS-S for fusion with target cells expressing high levels of ACE2. Thus, different host cell proteases activate SARS-S for virus-cell and cell-cell fusion and SARS-S cleavage at R667 and 758-RXXR-762 can be dispensable for SARS-S activation.« less

12 CFR 208.62 - Suspicious activity reports.

Code of Federal Regulations, 2011 CFR

2011-01-01

.... (c) SARs required. A member bank shall file a SAR with the appropriate Federal law enforcement... SARs. SARs are confidential. Any member bank subpoenaed or otherwise requested to disclose a SAR or the...

12 CFR 208.62 - Suspicious activity reports.

Code of Federal Regulations, 2012 CFR

2012-01-01

.... (c) SARs required. A member bank shall file a SAR with the appropriate Federal law enforcement... SARs. SARs are confidential. Any member bank subpoenaed or otherwise requested to disclose a SAR or the...

Combined DEM Extration Method from StereoSAR and InSAR

NASA Astrophysics Data System (ADS)

Zhao, Z.; Zhang, J. X.; Duan, M. Y.; Huang, G. M.; Yang, S. C.

2015-06-01

A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn't require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.

Remote sensing of a dynamic sub-arctic peatland reservoir using optical and synthetic aperture radar data

NASA Astrophysics Data System (ADS)

Larter, Jarod Lee

Stephens Lake, Manitoba is an example of a peatland reservoir that has undergone physical changes related to mineral erosion and peatland disintegration processes since its initial impoundment. In this thesis I focused on the processes of peatland upheaval, transport, and disintegration as the primary drivers of dynamic change within the reservoir. The changes related to these processes are most frequent after initial reservoir impoundment and decline over time. They continue to occur over 35 years after initial flooding. I developed a remote sensing approach that employs both optical and microwave sensors for discriminating land (Le. floating peatlands, forested land, and barren land) from open water within the reservoir. High spatial resolution visible and near-infrared (VNIR) optical data obtained from the QuickBird satellite, and synthetic aperture radar (SAR) microwave data obtained from the RADARSAT-1 satellite were implemented. The approach was facilitated with a Geographic Information System (GIS) based validation map for the extraction of optical and SAR pixel data. Each sensor's extracted data set was first analyzed separately using univariate and multivariate statistical methods to determine the discriminant ability of each sensor. The initial analyses were followed by an integrated sensor approach; the development of an image classification model; and a change detection analysis. Results showed excellent (> 95%) classification accuracy using QuickBird satellite image data. Discrimination and classification of studied land cover classes using SAR image texture data resulted in lower overall classification accuracies (˜ 60%). SAR data classification accuracy improved to > 90% when classifying only land and water, demonstrating SAR's utility as a land and water mapping tool. An integrated sensor data approach showed no considerable improvement over the use of optical satellite image data alone. An image classification model was developed that could be used to map both detailed land cover classes and the land and water interface within the reservoir. Change detection analysis over a seven year period indicated that physical changes related to mineral erosion, peatland upheaval, transport, and disintegration, and operational water level variation continue to take place in the reservoir some 35 years after initial flooding. This thesis demonstrates the ability of optical and SAR satellite image remote sensing data sets to be used in an operational context for the routine discrimination of the land and water boundaries within a dynamic peatland reservoir. Future monitoring programs would benefit most from a complementary image acquisition program in which SAR images, known for their acquisition reliability under cloud cover, are acquired along with optical images given their ability to discriminate land cover classes in greater detail.

Cleavage and Activation of the Severe Acute Respiratory Syndrome Coronavirus Spike Protein by Human Airway Trypsin-Like Protease ▿

PubMed Central

Bertram, Stephanie; Glowacka, Ilona; Müller, Marcel A.; Lavender, Hayley; Gnirss, Kerstin; Nehlmeier, Inga; Niemeyer, Daniela; He, Yuxian; Simmons, Graham; Drosten, Christian; Soilleux, Elizabeth J.; Jahn, Olaf; Steffen, Imke; Pöhlmann, Stefan

2011-01-01

The highly pathogenic severe acute respiratory syndrome coronavirus (SARS-CoV) poses a constant threat to human health. The viral spike protein (SARS-S) mediates host cell entry and is a potential target for antiviral intervention. Activation of SARS-S by host cell proteases is essential for SARS-CoV infectivity but remains incompletely understood. Here, we analyzed the role of the type II transmembrane serine proteases (TTSPs) human airway trypsin-like protease (HAT) and transmembrane protease, serine 2 (TMPRSS2), in SARS-S activation. We found that HAT activates SARS-S in the context of surrogate systems and authentic SARS-CoV infection and is coexpressed with the viral receptor angiotensin-converting enzyme 2 (ACE2) in bronchial epithelial cells and pneumocytes. HAT cleaved SARS-S at R667, as determined by mutagenesis and mass spectrometry, and activated SARS-S for cell-cell fusion in cis and trans, while the related pulmonary protease TMPRSS2 cleaved SARS-S at multiple sites and activated SARS-S only in trans. However, TMPRSS2 but not HAT expression rendered SARS-S-driven virus-cell fusion independent of cathepsin activity, indicating that HAT and TMPRSS2 activate SARS-S differentially. Collectively, our results show that HAT cleaves and activates SARS-S and might support viral spread in patients. PMID:21994442

Remote sensing of Northern mines: supporting operation and environmental monitoring in cold conditions

NASA Astrophysics Data System (ADS)

Tuomela, Anne; Davids, Corine; Knutsson, Sven; Knutsson, Roger; Rauhala, Anssi; Rossi, Pekka M.; Rouyet, Line

2017-04-01

Northern areas of Finland, Sweden and Norway have mineral-rich deposits. There are several active mines in the area but also closed ones and deposits with plans for future mining. With increasing demand for environmental protection in the sensitive Northern conditions, there is a need for more comprehensive monitoring of the mining environment. In our study, we aim to develop new opportunities to use remote sensing data from satellites and unmanned aerial vehicles (UAVs) in improving mining safety and monitoring, for example in the case of mine waste storage facilities. Remote sensing methods have evolved fast, and could in many cases enable precise, reliable, and cost-efficient data collection over large areas. The study has focused on four mining areas in Northern Fennoscandia. Freely available medium-resolution (e.g. Sentinel-1), commercial high-resolution (e.g. TerraSAR-X) and Synthetic Aperture Radar (SAR) data has been collected during 2015-2016 to study how satellite remote sensing could be used e.g. for displacement monitoring using SAR Interferometry (InSAR). Furthermore, UAVs have been utilized in similar data collection in a local scale, and also in collection of thermal infrared data for hydrological monitoring of the areas. The development and efficient use of the methods in mining areas requires experts from several fields. In addition, the Northern conditions with four distinct seasons bring their own challenges for the efficient use of remote sensing, and further complicate their integration as standardised monitoring methods for mine environments. Based on the initial results, remote sensing could especially enhance the monitoring of large-scale structures in mine areas such as tailings impoundments.

Monitoring of ground movement in open pit iron mines of Carajás Province (Amazon region) based on A-DInSAR techniques using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Silva, Guilherme Gregório; Mura, José Claudio; Paradella, Waldir Renato; Gama, Fabio Furlan; Temporim, Filipe Altoé

2017-04-01

Persistent scatterer interferometry (PSI) analysis of a large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground movement measurements based on a combination of differential SAR interferometry time-series (DTS) and PSI techniques, applied on a large area of extent with open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detecting linear and nonlinear ground movement. These mines have presented a history of instability, and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground-based radar and total station (prisms). Using a priori information regarding the topographic phase error and a phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. A set of 33 TerraSAR-X (TSX-1) images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multilook unwrapped interferograms using an extension of SVD to obtain the least-square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferograms to perform the PSI analysis. This procedure improved the capability of the PSI analysis for detecting high rates of deformation, as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risk control.

Monitoring of surface movement in a large area of the open pit iron mines (Carajás, Brazil) based on A-DInSAR techniques using TerraSAR-X data

NASA Astrophysics Data System (ADS)

Mura, José C.; Paradella, Waldir R.; Gama, Fabio F.; Silva, Guilherme G.

2016-10-01

PSI (Persistent Scatterer Interferometry) analysis of large area is always a challenging task regarding the removal of the atmospheric phase component. This work presents an investigation of ground deformation measurements based on a combination of DInSAR Time-Series (DTS) and PSI techniques, applied in a large area of open pit iron mines located in Carajás (Brazilian Amazon Region), aiming at detect high rates of linear and nonlinear ground deformation. These mines have presented a historical of instability and surface monitoring measurements over sectors of the mines (pit walls) have been carried out based on ground based radar and total station (prisms). By using a priori information regarding the topographic phase error and phase displacement model derived from DTS, temporal phase unwrapping in the PSI processing and the removal of the atmospheric phases can be performed more efficiently. A set of 33 TerraSAR-X-1 images, acquired during the period from March 2012 to April 2013, was used to perform this investigation. The DTS analysis was carried out on a stack of multi-look unwrapped interferogram using an extension of SVD to obtain the Least-Square solution. The height errors and deformation rates provided by the DTS approach were subtracted from the stack of interferogram to perform the PSI analysis. This procedure improved the capability of the PSI analysis to detect high rates of deformation as well as increased the numbers of point density of the final results. The proposed methodology showed good results for monitoring surface displacement in a large mining area, which is located in a rain forest environment, providing very useful information about the ground movement for planning and risks control.

Lack of innate interferon responses during SARS coronavirus infection in a vaccination and reinfection ferret model.

PubMed

Cameron, Mark J; Kelvin, Alyson A; Leon, Alberto J; Cameron, Cheryl M; Ran, Longsi; Xu, Luoling; Chu, Yong-Kyu; Danesh, Ali; Fang, Yuan; Li, Qianjun; Anderson, Austin; Couch, Ronald C; Paquette, Stephane G; Fomukong, Ndingsa G; Kistner, Otfried; Lauchart, Manfred; Rowe, Thomas; Harrod, Kevin S; Jonsson, Colleen B; Kelvin, David J

2012-01-01

In terms of its highly pathogenic nature, there remains a significant need to further define the immune pathology of SARS-coronavirus (SARS-CoV) infection, as well as identify correlates of immunity to help develop vaccines for severe coronaviral infections. Here we use a SARS-CoV infection-reinfection ferret model and a functional genomics approach to gain insight into SARS immunopathogenesis and to identify correlates of immune protection during SARS-CoV-challenge in ferrets previously infected with SARS-CoV or immunized with a SARS virus vaccine. We identified gene expression signatures in the lungs of ferrets associated with primary immune responses to SARS-CoV infection and in ferrets that received an identical second inoculum. Acute SARS-CoV infection prompted coordinated innate immune responses that were dominated by antiviral IFN response gene (IRG) expression. Reinfected ferrets, however, lacked the integrated expression of IRGs that was prevalent during acute infection. The expression of specific IRGs was also absent upon challenge in ferrets immunized with an inactivated, Al(OH)(3)-adjuvanted whole virus SARS vaccine candidate that protected them against SARS-CoV infection in the lungs. Lack of IFN-mediated immune enhancement in infected ferrets that were previously inoculated with, or vaccinated against, SARS-CoV revealed 9 IRG correlates of protective immunity. This data provides insight into the molecular pathogenesis of SARS-CoV and SARS-like-CoV infections and is an important resource for the development of CoV antiviral therapeutics and vaccines.

Teachers' Misconceptions and Questionable Practices when Using Putonghua as the Medium-of-Instruction: A Case Study of Hong Kong

ERIC Educational Resources Information Center

Tam, Angela Choi Fung

2012-01-01

Immediately after the handover of Hong Kong to China, the teaching of Chinese in Putonghua was promulgated by the Hong Kong SAR government as a long-term goal. However, no clear definition and guidance regarding Putonghua instruction has been provided to teachers to facilitate the smooth implementation of this change. A review of the literature…

Developing Creativity and Promoting Social Harmony: The Relationship between Government, School and Parents' Perceptions of Children's Creativity in Macao-SAR in China

ERIC Educational Resources Information Center

Vong, Keang-Ieng

2008-01-01

The promotion of creativity in young children has been included in the agenda of the educational authorities in mainland China since 2001. Since then, attempts to implement this policy have appeared in different forms. The educational bureaux take measures by publishing documents and guidelines on the subject. While some kindergartens endeavour to…

Serology of severe acute respiratory syndrome: implications for surveillance and outcome.

PubMed

Chen, Xinchun; Zhou, Boping; Li, Meizhong; Liang, Xiaorong; Wang, Huosheng; Yang, Guilin; Wang, Hui; Le, Xiaohua

2004-04-01

Severe acute respiratory syndrome (SARS) is a novel infectious disease. No information is currently available on host-specific immunity against the SARS coronavirus (CoV), and detailed characteristics of the epidemiology of SARS CoV infection have not been identified. ELISA was used to detect antibody to SARS CoV. Reverse-transcriptase polymerase chain reaction was used to detect SARS CoV RNA. T cells in peripheral blood of patients were quantified by flow cytometry. Of 36 patients with probable SARS CoV infection, 30 (83.3%) were positive for IgG antibody to SARS CoV; in contrast, only 3 of 48 patients with suspected SARS CoV infection, 0 of 112 patients with fever but without SARS, and 0 of 96 healthy control individuals were positive for it. IgG antibody to SARS CoV was first detected between day 5 and day 47 after onset of illness (mean +/- SD, 18.7+/-10.4). Detection of antibody to SARS CoV is useful in the diagnosis of SARS; however, at the incubation and initial phases of the illness, serological assay is of little value, because of late seroconversion in most patients.

Statistical properties of superactive regions during solar cycles 19-23

NASA Astrophysics Data System (ADS)

Chen, A. Q.; Wang, J. X.; Li, J. W.; Feynman, J.; Zhang, J.

2011-10-01

Context. Each solar activity cycle is characterized by a small number of superactive regions (SARs) that produce the most violent of space weather events with the greatest disastrous influence on our living environment. Aims: We aim to re-parameterize the SARs and study the latitudinal and longitudinal distributions of SARs. Methods: We select 45 SARs in solar cycles 21-23, according to the following four parameters: 1) the maximum area of sunspot group, 2) the soft X-ray flare index, 3) the 10.7 cm radio peak flux, and 4) the variation in the total solar irradiance. Another 120 SARs given by previous studies of solar cycles 19-23 are also included. The latitudinal and longitudinal distributions of the 165 SARs in both the Carrington frame and the dynamic reference frame during solar cycles 19-23 are studied statistically. Results: Our results indicate that these 45 SARs produced 44% of all the X class X-ray flares during solar cycles 21-23, and that all the SARs are likely to produce a very fast CME. The latitudinal distributions of SARs display the Maunder butterfly diagrams and SARs occur preferentially in the maximum period of each solar cycle. Northern hemisphere SARs dominated in solar cycles 19 and 20 and southern hemisphere SARs dominated in solar cycles 21 and 22. In solar cycle 23, however, SARs occurred about equally in each hemisphere. There are two active longitudes in both the northern and southern hemispheres, about 160°-200° apart. Applying the improved dynamic reference frame to SARs, we find that SARs rotate faster than the Carrington rate and there is no significant difference between the two hemispheres. The synodic periods are 27.19 days and 27.25 days for the northern and southern hemispheres, respectively. The longitudinal distribution of SARs is significantly non-axisymmetric and about 75% SARs occurred near two active longitudes with half widths of 45°. Appendix A is available in electronic form at http://www.aanda.org

Flood extent and water level estimation from SAR using data-model integration

NASA Astrophysics Data System (ADS)

Ajadi, O. A.; Meyer, F. J.

2017-12-01

Synthetic Aperture Radar (SAR) images have long been recognized as a valuable data source for flood mapping. Compared to other sources, SAR's weather and illumination independence and large area coverage at high spatial resolution supports reliable, frequent, and detailed observations of developing flood events. Accordingly, SAR has the potential to greatly aid in the near real-time monitoring of natural hazards, such as flood detection, if combined with automated image processing. This research works towards increasing the reliability and temporal sampling of SAR-derived flood hazard information by integrating information from multiple SAR sensors and SAR modalities (images and Interferometric SAR (InSAR) coherence) and by combining SAR-derived change detection information with hydrologic and hydraulic flood forecast models. First, the combination of multi-temporal SAR intensity images and coherence information for generating flood extent maps is introduced. The application of least-squares estimation integrates flood information from multiple SAR sensors, thus increasing the temporal sampling. SAR-based flood extent information will be combined with a Digital Elevation Model (DEM) to reduce false alarms and to estimate water depth and flood volume. The SAR-based flood extent map is assimilated into the Hydrologic Engineering Center River Analysis System (Hec-RAS) model to aid in hydraulic model calibration. The developed technology is improving the accuracy of flood information by exploiting information from data and models. It also provides enhanced flood information to decision-makers supporting the response to flood extent and improving emergency relief efforts.

Memory T cell responses targeting the SARS coronavirus persist up to 11 years post-infection.

PubMed

Ng, Oi-Wing; Chia, Adeline; Tan, Anthony T; Jadi, Ramesh S; Leong, Hoe Nam; Bertoletti, Antonio; Tan, Yee-Joo

2016-04-12

Severe acute respiratory syndrome (SARS) is a highly contagious infectious disease which first emerged in late 2002, caused by a then novel human coronavirus, SARS coronavirus (SARS-CoV). The virus is believed to have originated from bats and transmitted to human through intermediate animals such as civet cats. The re-emergence of SARS-CoV remains a valid concern due to the continual persistence of zoonotic SARS-CoVs and SARS-like CoVs (SL-CoVs) in bat reservoirs. In this study, the screening for the presence of SARS-specific T cells in a cohort of three SARS-recovered individuals at 9 and 11 years post-infection was carried out, and all memory T cell responses detected target the SARS-CoV structural proteins. Two CD8(+) T cell responses targeting the SARS-CoV membrane (M) and nucleocapsid (N) proteins were characterized by determining their HLA restriction and minimal T cell epitope regions. Furthermore, these responses were found to persist up to 11 years post-infection. An absence of cross-reactivity of these CD8(+) T cell responses against the newly-emerged Middle East respiratory syndrome coronavirus (MERS-CoV) was also demonstrated. The knowledge of the persistence of SARS-specific celullar immunity targeting the viral structural proteins in SARS-recovered individuals is important in the design and development of SARS vaccines, which are currently unavailable. Copyright © 2016 Elsevier Ltd. All rights reserved.

Local SAR in Parallel Transmission Pulse Design

PubMed Central

Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L.; Adalsteinsson, Elfar

2011-01-01

The management of local and global power deposition in human subjects (Specific Absorption Rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx RF pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo MRI scan. Additionally, the algorithm yields a Protocol-specific Ultimate Peak in Local SAR (PUPiL SAR), which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7T eight-channel transmit array. The method reduced peak local 10g SAR by 14–66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. PMID:22083594

Coupling Matched Molecular Pairs with Machine Learning for Virtual Compound Optimization.

PubMed

Turk, Samo; Merget, Benjamin; Rippmann, Friedrich; Fulle, Simone

2017-12-26

Matched molecular pair (MMP) analyses are widely used in compound optimization projects to gain insights into structure-activity relationships (SAR). The analysis is traditionally done via statistical methods but can also be employed together with machine learning (ML) approaches to extrapolate to novel compounds. The here introduced MMP/ML method combines a fragment-based MMP implementation with different machine learning methods to obtain automated SAR decomposition and prediction. To test the prediction capabilities and model transferability, two different compound optimization scenarios were designed: (1) "new fragments" which occurs when exploring new fragments for a defined compound series and (2) "new static core and transformations" which resembles for instance the identification of a new compound series. Very good results were achieved by all employed machine learning methods especially for the new fragments case, but overall deep neural network models performed best, allowing reliable predictions also for the new static core and transformations scenario, where comprehensive SAR knowledge of the compound series is missing. Furthermore, we show that models trained on all available data have a higher generalizability compared to models trained on focused series and can extend beyond chemical space covered in the training data. Thus, coupling MMP with deep neural networks provides a promising approach to make high quality predictions on various data sets and in different compound optimization scenarios.

SEMICONDUCTOR INTEGRATED CIRCUITS: A high performance 90 nm CMOS SAR ADC with hybrid architecture

NASA Astrophysics Data System (ADS)

Xingyuan, Tong; Jianming, Chen; Zhangming, Zhu; Yintang, Yang

2010-01-01

A 10-bit 2.5 MS/s SAR A/D converter is presented. In the circuit design, an R-C hybrid architecture D/A converter, pseudo-differential comparison architecture and low power voltage level shifters are utilized. Design challenges and considerations are also discussed. In the layout design, each unit resistor is sided by dummies for good matching performance, and the capacitors are routed with a common-central symmetry method to reduce the nonlin-earity error. This proposed converter is implemented based on 90 nm CMOS logic process. With a 3.3 V analog supply and a 1.0 V digital supply, the differential and integral nonlinearity are measured to be less than 0.36 LSB and 0.69 LSB respectively. With an input frequency of 1.2 MHz at 2.5 MS/s sampling rate, the SFDR and ENOB are measured to be 72.86 dB and 9.43 bits respectively, and the power dissipation is measured to be 6.62 mW including the output drivers. This SAR A/D converter occupies an area of 238 × 214 μm2. The design results of this converter show that it is suitable for multi-supply embedded SoC applications.

SEMICONDUCTOR INTEGRATED CIRCUITS A 10-bit 200-kS/s SAR ADC IP core for a touch screen SoC

NASA Astrophysics Data System (ADS)

Xingyuan, Tong; Yintang, Yang; Zhangming, Zhu; Wenfang, Sheng

2010-10-01

Based on a 5 MSBs (most-significant-bits)-plus-5 LSBs (least-significant-bits) C-R hybrid D/A conversion and low-offset pseudo-differential comparison approach, with capacitor array axially symmetric layout topology and resistor string low gradient mismatch placement method, an 8-channel 10-bit 200-kS/s SAR ADC (successive-approximation-register analog-to-digital converter) IP core for a touch screen SoC (system-on-chip) is implemented in a 0.18 μm 1P5M CMOS logic process. Design considerations for the touch screen SAR ADC are included. With a 1.8 V power supply, the DNL (differential non-linearity) and INL (integral non-linearity) of this converter are measured to be about 0.32 LSB and 0.81 LSB respectively. With an input frequency of 91 kHz at 200-kS/s sampling rate, the spurious-free dynamic range and effective-number-of-bits are measured to be 63.2 dB and 9.15 bits respectively, and the power is about 136 μW. This converter occupies an area of about 0.08 mm2. The design results show that it is very suitable for touch screen SoC applications.

MR fingerprinting using the quick echo splitting NMR imaging technique.

PubMed

Jiang, Yun; Ma, Dan; Jerecic, Renate; Duerk, Jeffrey; Seiberlich, Nicole; Gulani, Vikas; Griswold, Mark A

2017-03-01

The purpose of the study is to develop a quantitative method for the relaxation properties with a reduced radio frequency (RF) power deposition by combining magnetic resonance fingerprinting (MRF) technique with quick echo splitting NMR imaging technique (QUEST). A QUEST-based MRF sequence was implemented to acquire high-order echoes by increasing the gaps between RF pulses. Bloch simulations were used to calculate a dictionary containing the range of physically plausible signal evolutions using a range of T 1 and T 2 values based on the pulse sequence. MRF-QUEST was evaluated by comparing to the results of spin-echo methods. The specific absorption rate (SAR) of MRF-QUEST was compared with the clinically available methods. MRF-QUEST quantifies the relaxation properties with good accuracy at the estimated head SAR of 0.03 W/kg. T 1 and T 2 values estimated by MRF-QUEST are in good agreement with the traditional methods. The combination of the MRF and the QUEST provides an accurate quantification of T 1 and T 2 simultaneously with reduced RF power deposition. The resulting lower SAR may provide a new acquisition strategy for MRF when RF energy deposition is problematic. Magn Reson Med 77:979-988, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

50 CFR 600.1008 - Implementation plan and implementation regulations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Implementation plan and implementation... Capacity Reduction Framework § 600.1008 Implementation plan and implementation regulations. (a) As soon as... period, a proposed implementation plan and implementation regulations. During the public comment period...

Status of the 3D Elevation Program, 2015

USGS Publications Warehouse

Sugarbaker, Larry J.; Eldridge, Diane F.; Jason, Allyson L.; Lukas, Vicki; Saghy, David L.; Stoker, Jason M.; Thunen, Diana R.

2017-01-18

The 3D Elevation Program (3DEP) is a cooperative activity to collect light detection and ranging (lidar) data for the conterminous United States, Hawaii, and U.S. territories; and interferometric synthetic aperture radar (IfSAR) elevation data for Alaska during an 8-year period. The U.S. Geological Survey (USGS) and partner organizations acquire high-quality three-dimensional elevation data for the United States and its territories that support requirements beyond what could be realized if agencies independently pursued lidar and IfSAR data collection activities. Data collection rates have been increasing as a growing number of State and Federal agencies participate in cooperative data acquisition projects. USGS and partner agencies expanded data collection, completed the initial product delivery systems and implemented changes to the program governance to include a restructuring of the 3DEP working group and formalizing the relationship to the Federal Geographic Data Committee during the final year (2015) of program preparation.

Waveform synthesis for imaging and ranging applications

DOEpatents

Doerry, Armin W.; Dudley, Peter A.; Dubert, Dale F.; Tise, Bertice L.

2004-12-07

Frequency dependent corrections are provided for quadrature imbalance and Local Oscillator (LO) feed-through. An operational procedure filters imbalance and LO feed-through effects without prior calibration or equalization. Waveform generation can be adjusted/corrected in a synthetic aperture radar system (SAR), where a rolling phase shift is applied to the SAR's QDWS signal where it is demodulated in a receiver; unwanted energies, such as LO feed-through and/or imbalance energy, are separated from a desired signal in Doppler; the separated energy is filtered from the receiver leaving the desired signal; and the separated energy in the receiver is measured to determine the degree of imbalance that is represented by it. Calibration methods can also be implemented into synthesis. The degree of LO feed-through and imbalance can be used to determine calibration values that can then be provided as compensation for frequency dependent errors in components, such as the QDWS and SSB mixer, affecting quadrature signal quality.

Satellites for distress alerting and locating: Report by Interagency Committee for Search and Rescue Ad Hoc Working Group

NASA Technical Reports Server (NTRS)

Ehrlich, E.

1976-01-01

The background behind the congressional legislation that led to the requirement for the Emergency Locator Transmitter (ELT) and the Emergency Position-Indicating Radio Beacon (EPIRB) to be installed on certain types of aircraft and inspected marine vessels respectively is discussed. The DAL problem is discussed for existing ELT and EPIRB equipped aircraft and ships. It is recognized that the DAL requirement for CONUS and Alaska and the maritime regions are not identical. In order to address the serious DAL problem which currently exists in CONUS and Alaska, a low orbiting satellite system evolves as the most viable and cost effective alternative that satisfies the overall SAR system design requirements. A satellite system designed to meet the needs of the maritime regions could be either low orbiting or geostationary. The conclusions drawn from this report support the recommendation to proceed with the implementation of a SAR orbiting satellite system.

Grid Based Technologies for in silico Screening and Drug Design.

PubMed

Potemkin, Vladimir; Grishina, Maria

2018-03-08

Various techniques for rational drug design are presented in the paper. The methods are based on a substitution of antipharmacophore atoms of the molecules of training dataset by new atoms and/or group of atoms increasing the atomic bioactivity increments obtained at a SAR study. Furthermore, a design methodology based on the genetic algorithm DesPot for discrete optimization and generation of new drug candidate structures is described. Additionally, wide spectra of SAR approaches (3D/4D QSAR interior and exterior-based methods - BiS, CiS, ConGO, CoMIn, high-quality docking method - ReDock) using MERA force field and/or AlteQ quantum chemical method for correct prognosis of bioactivity and bioactive probability is described. The design methods are implemented now at www.chemosophia.com web-site for online computational services. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Waveform Synthesizer For Imaging And Ranging Applications

DOEpatents

Dubbert, Dale F.; Dudley, Peter A.; Doerry, Armin W.; Tise, Bertice L.

2004-12-28

Frequency dependent corrections are provided for Local Oscillator (LO) feed-through. An operational procedure filters LO feed-through effects without prior calibration or equalization. Waveform generation can be adjusted/corrected in a synthetic aperture radar system (SAR), where a rolling phase shift is applied to the SAR's QDWS signal where it is demodulated in a receiver, unwanted energies, such as LO feed-through energy, are separated from a desired signal in Doppler; the separated energy is filtered from the receiver leaving the desired signal; and the separated energy in the receiver is measured to determine the degree of imbalance that is represented by it. Calibration methods can also be implemented into synthesis. The degree of LO feed-through can be used to determine calibration values that can then be provided as compensation for frequency dependent errors in components, such as the QDWS and SSB mixer, affecting quadrature signal quality.

PAF: A software tool to estimate free-geometry extended bodies of anomalous pressure from surface deformation data

NASA Astrophysics Data System (ADS)

Camacho, A. G.; Fernández, J.; Cannavò, F.

2018-02-01

We present a software package to carry out inversions of surface deformation data (any combination of InSAR, GPS, and terrestrial data, e.g., EDM, levelling) as produced by 3D free-geometry extended bodies with anomalous pressure changes. The anomalous structures are described as an aggregation of elementary cells (whose effects are estimated as coming from point sources) in an elastic half space. The linear inverse problem (considering some simple regularization conditions) is solved by means of an exploratory approach. This software represents the open implementation of a previously published methodology (Camacho et al., 2011). It can be freely used with large data sets (e.g. InSAR data sets) or with data coming from small control networks (e.g. GPS monitoring data), mainly in volcanic areas, to estimate the expected pressure bodies representing magmatic intrusions. Here, the software is applied to some real test cases.

Techniques and Tools for Estimating Ionospheric Effects in Interferometric and Polarimetric SAR Data

NASA Technical Reports Server (NTRS)

Rosen, P.; Lavalle, M.; Pi, X.; Buckley, S.; Szeliga, W.; Zebker, H.; Gurrola, E.

2011-01-01

The InSAR Scientific Computing Environment (ISCE) is a flexible, extensible software tool designed for the end-to-end processing and analysis of synthetic aperture radar data. ISCE inherits the core of the ROI_PAC interferometric tool, but contains improvements at all levels of the radar processing chain, including a modular and extensible architecture, new focusing approach, better geocoding of the data, handling of multi-polarization data, radiometric calibration, and estimation and correction of ionospheric effects. In this paper we describe the characteristics of ISCE with emphasis on the ionospheric modules. To detect ionospheric anomalies, ISCE implements the Faraday rotation method using quadpolarimetric images, and the split-spectrum technique using interferometric single-, dual- and quad-polarimetric images. The ability to generate co-registered time series of quad-polarimetric images makes ISCE also an ideal tool to be used for polarimetric-interferometric radar applications.

Analysis of data acquired by synthetic aperture radar and LANDSAT Multispectral Scanner over Kershaw County, South Carolina, during the summer season

NASA Technical Reports Server (NTRS)

Wu, S. T.

1983-01-01

Data acquired by synthetic aperture radar (SAR) and LANDSAT multispectral scanner (MSS) were processed and analyzed to derive forest-related resources inventory information. The SAR data were acquired by using the NASA aircraft X-band SAR with linear (HH, VV) and cross (HV, VH) polarizations and the SEASAT L-band SAR. After data processing and data quality examination, the three polarization (HH, HV, and VV) data from the aircraft X-band SAR were used in conjunction with LANDSAT MSS for multisensor data classification. The results of accuracy evaluation for the SAR, MSS and SAR/MSS data using supervised classification show that the SAR-only data set contains low classification accuracy for several land cover classes. However, the SAR/MSS data show that significant improvement in classification accuracy is obtained for all eight land cover classes. These results suggest the usefulness of using combined SAR/MSS data for forest-related cover mapping. The SAR data also detect several small special surface features that are not detectable by MSS data.

The replication of a mouse adapted SARS-CoV in a mouse cell line stably expressing the murine SARS-CoV receptor mACE2 efficiently induces the expression of proinflammatory cytokines

PubMed Central

Regla-Nava, Jose A.; Jimenez-Guardeño, Jose M.; Nieto-Torres, Jose L.; Gallagher, Thomas M.; Enjuanes, Luis; DeDiego, Marta L.

2013-01-01

Infection of conventional mice with a mouse adapted (MA15) severe acute respiratory syndrome (SARS) coronavirus (CoV) reproduces many aspects of human SARS such as pathological changes in lung, viremia, neutrophilia, and lethality. However, established mouse cell lines highly susceptible to mouse-adapted SARS-CoV infection are not available. In this work, efficiently transfectable mouse cell lines stably expressing the murine SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) have been generated. These cells yielded high SARS-CoV-MA15 titers and also served as excellent tools for plaque assays. In addition, in these cell lines, SARS-CoV-MA15 induced the expression of proinflammatory cytokines and IFN-β, mimicking what has been observed in experimental animal models infected with SARS-CoV and SARS patients. These cell lines are valuable tools to perform in vitro studies in a mouse cell system that reflects the species used for in vivo studies of SARS-CoV-MA15 pathogenesis. PMID:23911968

Mathematical modeling and SAR simulation multifunction SAR technology efforts

NASA Technical Reports Server (NTRS)

Griffin, C. R.; Estes, J. M.

1981-01-01

The orbital SAR (synthetic aperture radar) simulation data was used in several simulation efforts directed toward advanced SAR development. Efforts toward simulating an operational radar, simulation of antenna polarization effects, and simulation of SAR images at serveral different wavelengths are discussed. Avenues for improvements in the orbital SAR simulation and its application to the development of advanced digital radar data processing schemes are indicated.

Severe acute respiratory syndrome (SARS): knowledge, attitudes, practices and sources of information among physicians answering a SARS fever hotline service.

PubMed

Deng, J-F; Olowokure, B; Kaydos-Daniels, S C; Chang, H-J; Barwick, R S; Lee, M-L; Deng, C-Y; Factor, S H; Chiang, C-E; Maloney, S A

2006-01-01

In June 2003, Taiwan introduced a severe acute respiratory syndrome (SARS) telephone hotline service to provide concerned callers with rapid access to information, advice and appropriate referral where necessary. This paper reports an evaluation of the knowledge, attitude, practices and sources of information relating to SARS among physicians who staffed the SARS fever hotline service. A retrospective survey was conducted using a self-administered postal questionnaire. Participants were physicians who staffed a SARS hotline during the SARS epidemic in Taipei, Taiwan from June 1 to 10, 2003. A response rate of 83% was obtained. All respondents knew the causative agent of SARS, and knowledge regarding SARS features and preventive practices was good. However, only 54% of respondents knew the incubation period of SARS. Hospital guidelines and news media were the major information sources. In responding to two case scenarios most physicians were likely to triage callers at high risk of SARS appropriately, but not callers at low risk. Less than half of all respondents answered both scenarios correctly. The results obtained suggest that knowledge of SARS was generally good although obtained from both medical and non-medical sources. Specific knowledge was however lacking in certain areas and this affected the ability to appropriately triage callers. Standardized education and assessment of prior knowledge of SARS could improve the ability of physicians to triage callers in future outbreaks.

Mitigating illumination gradients in a SAR image based on the image data and antenna beam pattern

DOEpatents

Doerry, Armin W.

2013-04-30

Illumination gradients in a synthetic aperture radar (SAR) image of a target can be mitigated by determining a correction for pixel values associated with the SAR image. This correction is determined based on information indicative of a beam pattern used by a SAR antenna apparatus to illuminate the target, and also based on the pixel values associated with the SAR image. The correction is applied to the pixel values associated with the SAR image to produce corrected pixel values that define a corrected SAR image.

Evaluation of the operational SAR based Baltic sea ice concentration products

NASA Astrophysics Data System (ADS)

Karvonen, Juha

Sea ice concentration is an important ice parameter both for weather and climate modeling and sea ice navigation. We have developed an fully automated algorithm for sea ice concentration retrieval using dual-polarized ScanSAR wide mode RADARSAT-2 data. RADARSAT-2 is a C-band SAR instrument enabling dual-polarized acquisition in ScanSAR mode. The swath width for the RADARSAT-2 ScanSAR mode is about 500 km, making it very suitable for operational sea ice monitoring. The polarization combination used in our concentration estimation is HH/HV. The SAR data is first preprocessed, the preprocessing consists of geo-rectification to Mercator projection, incidence angle correction fro both the polarization channels. and SAR mosaicking. After preprocessing a segmentation is performed for the SAR mosaics, and some single-channel and dual-channel features are computed for each SAR segment. Finally the SAR concentration is estimated based on these segment-wise features. The algorithm is similar as introduced in Karvonen 2014. The ice concentration is computed daily using a daily RADARSAT-2 SAR mosaic as its input, and it thus gives the concentration estimated at each Baltic Sea location based on the most recent SAR data at the location. The algorithm has been run in an operational test mode since January 2014. We present evaluation of the SAR-based concentration estimates for the Baltic ice season 2014 by comparing the SAR results with gridded the Finnish Ice Service ice charts and ice concentration estimates from a radiometer algorithm (AMSR-2 Bootstrap algorithm results). References: J. Karvonen, Baltic Sea Ice Concentration Estimation Based on C-Band Dual-Polarized SAR Data, IEEE Transactions on Geoscience and Remote Sensing, in press, DOI: 10.1109/TGRS.2013.2290331, 2014.

Coping with future epidemics: Tai chi practice as an overcoming strategy used by survivors of severe acute respiratory syndrome (SARS) in post-SARS Hong Kong.

PubMed

Siu, Judy Yuen-Man

2016-06-01

Although SARS had been with a controversial topic for a decade at the time of this study, numerous SARS survivors had not yet physically, psychologically or socially recovered from the aftermath of SARS. Among chronically ill patients, the use of complementary and alternative medicine (CAM) is reported to be widespread. However, extremely little is known about the use of CAM by SARS survivors in the post-SARS period and even less is known about how the use of CAM is related to the unpleasant social and medical-treatment experiences of SARS survivors, their eagerness to re-establish social networks, and their awareness to prepare for future epidemics. To investigate the motivations for practising tai chi among SARS survivors in post-SARS Hong Kong. Using a qualitative approach, I conducted individual semi-structured interviews with 35 SARS survivors, who were purposively sampled from a tai chi class of a SARS-patient self-help group in Hong Kong. Health concerns and social experiences motivated the participants to practise tai chi in post-SARS Hong Kong. Experiencing health deterioration in relation to SARS-associated sequelae, coping with unpleasant experiences during follow-up biomedical treatments, a desire to regain an active role in recovery and rehabilitation, overcoming SARS-associated stigmas by establishing a new social network and preparing for potential future stigmatization and discrimination were the key motivators for them. The participants practised tai chi not only because they sought to improve their health but also because it provided a crucial social function and meaning to them. © 2014 John Wiley & Sons Ltd.

Large Spatial Scale Ground Displacement Mapping through the P-SBAS Processing of Sentinel-1 Data on a Cloud Computing Environment

NASA Astrophysics Data System (ADS)

Casu, F.; Bonano, M.; de Luca, C.; Lanari, R.; Manunta, M.; Manzo, M.; Zinno, I.

2017-12-01

Since its launch in 2014, the Sentinel-1 (S1) constellation has played a key role on SAR data availability and dissemination all over the World. Indeed, the free and open access data policy adopted by the European Copernicus program together with the global coverage acquisition strategy, make the Sentinel constellation as a game changer in the Earth Observation scenario. Being the SAR data become ubiquitous, the technological and scientific challenge is focused on maximizing the exploitation of such huge data flow. In this direction, the use of innovative processing algorithms and distributed computing infrastructures, such as the Cloud Computing platforms, can play a crucial role. In this work we present a Cloud Computing solution for the advanced interferometric (DInSAR) processing chain based on the Parallel SBAS (P-SBAS) approach, aimed at processing S1 Interferometric Wide Swath (IWS) data for the generation of large spatial scale deformation time series in efficient, automatic and systematic way. Such a DInSAR chain ingests Sentinel 1 SLC images and carries out several processing steps, to finally compute deformation time series and mean deformation velocity maps. Different parallel strategies have been designed ad hoc for each processing step of the P-SBAS S1 chain, encompassing both multi-core and multi-node programming techniques, in order to maximize the computational efficiency achieved within a Cloud Computing environment and cut down the relevant processing times. The presented P-SBAS S1 processing chain has been implemented on the Amazon Web Services platform and a thorough analysis of the attained parallel performances has been performed to identify and overcome the major bottlenecks to the scalability. The presented approach is used to perform national-scale DInSAR analyses over Italy, involving the processing of more than 3000 S1 IWS images acquired from both ascending and descending orbits. Such an experiment confirms the big advantage of exploiting large computational and storage resources of Cloud Computing platforms for large scale DInSAR analysis. The presented Cloud Computing P-SBAS processing chain can be a precious tool in the perspective of developing operational services disposable for the EO scientific community related to hazard monitoring and risk prevention and mitigation.

CryoSat Level1b SAR/SARin BaselineC: Product Format and Algorithm Improvements

NASA Astrophysics Data System (ADS)

Scagliola, Michele; Fornari, Marco; Di Giacinto, Andrea; Bouffard, Jerome; Féménias, Pierre; Parrinello, Tommaso

2015-04-01

CryoSat was launched on the 8th April 2010 and is the first European ice mission dedicated to the monitoring of precise changes in the thickness of polar ice sheets and floating sea ice. Cryosat carries an innovative radar altimeter called the Synthetic Aperture Interferometric Altimeter (SIRAL), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach a significantly improved along track resolution with respect to traditional pulse-width limited altimeters. CryoSat is the first altimetry mission operating in SAR mode and continuous improvements in the Level1 Instrument Processing Facility (IPF1) are being identified, tested and validated in order to improve the quality of the Level1b products. The current IPF, Baseline B, was released in operation in February 2012. A reprocessing campaign followed, in order to reprocess the data since July 2010. After more than 2 years of development, the release in operations of Baseline C is expected in the first half of 2015. BaselineC Level1b products will be distributed in an updated format, including for example the attitude information (roll, pitch and yaw) and, for SAR/SARIN, the waveform length doubled with respect to Baseline B. Moreveor, various algorithm improvements have been identified: • a datation bias of about -0.5195 ms will be corrected (SAR/SARIn) • a range bias of about 0.6730 m will be corrected (SAR/SARIn) • a roll bias of 0.1062 deg and a pitch bias of 0.0520 deg • Surface sample stack weighting to filter out the single look echoes acquired at highest look angle, that results in a sharpening of the 20Hz waveforms With the operational release of BaselineC, the second CryoSat reprocessing campaign will be initiated, taking benefit of the upgrade implemented in the IPF1 processing chain but also at IPF2 level. The reprocessing campaign will cover the full Cryosat mission starting on 16th July 2010. This poster details the new information that will be added in the CryoSat BaselineC Level1b SAR/SARin products and the main quality improvements will be described.

Characterising and improving the performance of the Sentinel-3 SRAL altimeter: A Report from SCOOP, SHAPE & SPICE Projects

NASA Astrophysics Data System (ADS)

Restano, Marco; Ambrózio, Américo; Cotton, David; Scoop Team; Fabry, Pierre; Shape Team; McMillan, Malcolm; Spice Team; Benveniste, Jérôme

2017-04-01

Under the ESA Scientific Exploitation of Operational Missions (SEOM) Programme, 3 Projects are currently underway to accurately characterise and improve the performance of the Sentinel-3 SRAL SAR mode altimeter. They are: 1) SCOOP (SAR Altimetry Coastal & Open Ocean Performance Exploitation and Roadmap Study) for Coastal and Open Ocean; 2) SHAPE (Sentinel-3 Hydrologic Altimetry PrototypE) for Inland Water; 3) SPICE (Sentinel-3 Performance improvement for ICE sheets) for Ice Sheets. As projects started before the launch of Sentinel-3 (a full SAR mission), calibrated Cryosat-2 data have been used as input to a processor replicating the Sentinel-3 baseline processing. For the SCOOP project, a first test dataset has been released to end users including data from 10 regions of interest. The successful SAMOSA retracker, adopted in the previous CP4O Project (CryoSat Plus for Oceans), has been readapted to re-track Sentinel-3 waveforms. An improved version of SAMOSA will be released at the end of the project. The SHAPE project is working towards the design and assessment of alternative/innovative techniques not implemented in the Sentinel-3 ground segment (performing no Inland Water dedicated processing). Both rivers and lakes will be studied. Amazon, Brahmaputra and Danube have been selected as rivers, whereas Titicaca and Vanern have been chosen as lakes. The study will include the assimilation of output products into hydrological models for all regions of interest. A final dataset will be provided to end users. The SPICE project is addressing four high level objectives: 1) Assess and improve the Delay-Doppler altimeter processing for ice sheets. 2) Assess and develop SAR waveform retrackers for ice sheets. 3) Evaluate the performance of SAR altimetry relative to conventional pulse limited altimetry. 4) Assess the impact on SAR altimeter measurements of radar wave interaction with the snowpack. Dataset used for validation include ICESat and IceBridge products. Vostok, Dome C and the Spirit Sector (all located in Antarctica) have been selected, along with the Russell Glacier in Greenland, as regions of interest. In the frame of both SCOOP and SHAPE projects, improved wet troposphere corrections will be estimated for all regions of interest.

SAAM: A Method for Analyzing the Properties of Software Architectures

DTIC Science & Technology

2007-05-01

ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 10 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b . ABSTRACT unclassified c. THIS PAGE...of Software Engineering. [3] Bass, L., Clapper, B ., Hardy, E., Kazman, R., Seacord, R. “Serpent: A User Interface Management System”. Proceedings of...Forthcoming. [9] Green, J., Selby, B . “Dynamic Planning and Software Mainte- nance: A Fiscal Approach”, Naval Postgraduate School, Monterey, CA, NTIS

The Pandemic Influenza Policy Model: A Planning Tool for Military Public Health Officials

DTIC Science & Technology

2009-06-01

Containment . Geneva , WHO , 2006. 7. Luke CJ , Subbarao K : Vaccines for pandemic infl uenza . Emerg Infect Dis 2006 ; 12 (1) : 66 – 72...Report (SAR) 18. NUMBER OF PAGES 9 19a. NAME OF RESPONSIBLE PERSON a. REPORT unclassified b . ABSTRACT unclassified c. THIS PAGE unclassified...simulations . Simulation 2005 ; 81 (10) : 671 – 99 . 19. Pourbohloul B , Meyers LA , Skowronski DM , Krajden M , Patrick DM , Brunham RC

Assessment of the performance characteristics of a prototype 12-element capacitive contact flexible microstrip applicator (CFMA-12) for superficial hyperthermia.

PubMed

Lee, W M; Gelvich, E A; van der Baan, P; Mazokhin, V N; van Rhoon, G C

2004-09-01

The electrical performance of the CFMA-12 operating at 433 MHz is assessed under laboratory conditions using a RF network analyser. From measurements of the scattering parameters of the CFMA-12 on both a multi-layered muscle- and fat/muscle-equivalent phantom, the optimal water bolus thickness, at which the transfer of the energy to the phantom configuration is maximal, is determined to be approximately 1 cm. The SAR distribution of the CFMA-12 in a multi-layered muscle-equivalent phantom is characterized using Schottky diode sheets and a TVS-600 IR camera. From the SAR measurements using the Schottky diode sheets it is shown that the contribution of the E(x) component to the SAR (SAR(x)) is maximal 7% of the contribution of the E(y)component to the SAR (SAR(y)) at different layers in both phantom configurations. The complete SAR distribution (SAR(tot)) at different depths is measured using the power pulse technique. From these measurements, it can be seen that SAR(y)at a depth of 0 cm in the muscle-equivalent phantom represents up to 80% of SAR(tot). At 1 and 2 cm depth, SAR(y) is up to 95% of SAR(tot). Therefore, in homogeneous muscle-equivalent phantoms, E(y) is the largest E-field component and measurement of SAR(y) distribution is sufficient to characterize SAR-steering performance of the CFMA-12. SAR steering measurements at 1 cm depth in the muscle-equivalent phantom show that the SAR maximum varies by 40% (1 SD) around the average value of 38.8 W kg(-1) (range 10-65 W kg(-1)) between single antenna elements. The effective fieldsize (E(50)) varies by 14% (1 SD) around the average value of 19.1 cm(2).

Limits, complementarity and improvement of Advanced SAR Interferometry monitoring of anthropogenic subsidence/uplift due to long term CO2 storage

NASA Astrophysics Data System (ADS)

de Michele, M.; Raucoules, D.; Rohmer, J.; Loschetter, A.; Raffard, D.; Le Gallo, Y.

2013-12-01

A prerequisite to the large scale industrial development of CO2 Capture and geological Storage is the demonstration that the storage is both efficient and safe. In this context, precise uplift/subsidence monitoring techniques constitute a key component of any CO2 storage risk management. Space-borne Differential SAR (Synthetic Aperture Radar) interferometry is a promising monitoring technique. It can provide valuable information on vertical positions of a set of scatterer undergoing surface deformation induced by volumetric changes through time and space caused by CO2 injection in deep aquifers. To what extent ? To date, InSAR techniques have been successfully used in a variety of case-studies involving the measure of surface deformation caused by subsurface fluid withdrawal / injection. For instance, groundwater flow characterization in complex aquifers systems, oil / gas field characterization, verification of enhanced oil recovery efficiency, monitoring of seasonal gas storage. The successful use of InSAR is strictly related to the favourable scattering conditions in terms of spatial distribution of targets and their temporal stability. In arid regions, natural radar scatterers density can be very high, exceeding 1,000 per square km. But future onshore industrial-scale CO2 storage sites are planned in more complex land-covers such as agricultural or vegetated terrains. Those terrains are characterized by poor to moderate radar scatterers density, which decrease the detection limits of the space-borne interferometric technique. The present study discusses the limits and constraints of advanced InSAR techniques applied to deformation measurements associated with CO2 injection/storage into deep aquifers in the presence of agricultural and vegetated land-covers. We explore different options to enhance the measurement performances of InSAR techniques. As a first option, we propose to optimize the deployment of a network of 'artificial' scatterers, i.e. corner reflectors (artificial devices installed on ground to provide high backscatter to the radar signal) to complement the existing 'natural' network. The methodology is iterative and adaptive to the spatial and temporal extent of the detectable deforming region. We take into account the need of a change in sensors characteristics (for a very long term monitoring 10-50 years) that could result in a need of re-organisation of the network. Our discussion is supported by the estimates of the expected spatio-temporal evolution of surface vertical displacements caused by CO2 injection at depth by combining the approximate analytical solutions for pressure build-up during CO2 injection in deep aquifers and the poro-elastic behaviour of the reservoir under injection. As second option, we then review different advanced InSAR algorithms that could improve the displacement measurements using natural scatterers over vegetated areas.

12 CFR 390.355 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Activity Report on the form prescribed by the FDIC. (3) SARs required. A State savings association shall... to supervisory action. (11) Obtaining SARs. A State savings association may obtain SARs and the... SARs. SARs are confidential. Any institution or person subpoenaed or otherwise requested to disclose a...

12 CFR 390.355 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Activity Report on the form prescribed by the FDIC. (3) SARs required. A State savings association shall... to supervisory action. (11) Obtaining SARs. A State savings association may obtain SARs and the... SARs. SARs are confidential. Any institution or person subpoenaed or otherwise requested to disclose a...

12 CFR 390.355 - Suspicious Activity Reports and other reports and statements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Activity Report on the form prescribed by the FDIC. (3) SARs required. A State savings association shall... to supervisory action. (11) Obtaining SARs. A State savings association may obtain SARs and the... SARs. SARs are confidential. Any institution or person subpoenaed or otherwise requested to disclose a...

The replication of a mouse adapted SARS-CoV in a mouse cell line stably expressing the murine SARS-CoV receptor mACE2 efficiently induces the expression of proinflammatory cytokines.

PubMed

Regla-Nava, Jose A; Jimenez-Guardeño, Jose M; Nieto-Torres, Jose L; Gallagher, Thomas M; Enjuanes, Luis; DeDiego, Marta L

2013-11-01

Infection of conventional mice with a mouse adapted (MA15) severe acute respiratory syndrome (SARS) coronavirus (CoV) reproduces many aspects of human SARS such as pathological changes in lung, viremia, neutrophilia, and lethality. However, established mouse cell lines highly susceptible to mouse-adapted SARS-CoV infection are not available. In this work, efficiently transfectable mouse cell lines stably expressing the murine SARS-CoV receptor angiotensin converting enzyme 2 (ACE2) have been generated. These cells yielded high SARS-CoV-MA15 titers and also served as excellent tools for plaque assays. In addition, in these cell lines, SARS-CoV-MA15 induced the expression of proinflammatory cytokines and IFN-β, mimicking what has been observed in experimental animal models infected with SARS-CoV and SARS patients. These cell lines are valuable tools to perform in vitro studies in a mouse cell system that reflects the species used for in vivo studies of SARS-CoV-MA15 pathogenesis. Copyright © 2013 Elsevier B.V. All rights reserved.

Monitoring Building Deformation with InSAR: Experiments and Validation.

PubMed

Yang, Kui; Yan, Li; Huang, Guoman; Chen, Chu; Wu, Zhengpeng

2016-12-20

Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated.

SAR Altimetry Processing on Demand Service for CryoSat-2 and Sentinel-3 at ESA G-POD

NASA Astrophysics Data System (ADS)

Dinardo, Salvatore; Lucas, Bruno; Benveniste, Jerome

2015-12-01

The scope of this work is to feature the new ESA service (SARvatore) for the exploitation of the CryoSat-2 data, designed and developed entirely by the Altimetry Team at ESA-ESRIN EOP-SER (Earth Observation - Exploitation, Research and Development). The G-POD Service, SARvatore (SAR Versatile Altimetric Toolkit for Ocean Research & Exploitation) for CryoSat-2, is a web platform that provides the capability to process on-line and on-demand CryoSat-2 SAR/SARIN data, from L1a (FBR) data products until SAR/SARIN Level-2 geophysical data products.. The Processor will make use of the G-POD (Grid-Processing On Demand) distributed computing platform to deliver timely the output data products. These output data products are generated in standard NetCDF format (using CF Convention), and they are compatible with BRAT (Basic Radar Altimetry Toolbox) and other NetCDF tool. Using the G-POD graphic interface, it is easy to select the geographical area of interest along with the time-frame of interest, based on the Cryosat-2 SAR/SARIN FBR data products availability in the service's catalogue. After the task submission, the users can follow, in real time, the status of the processing task. The processor prototype is versatile in the sense that the users can customize and adapt the processing, according their specific requirements, setting a list of configurable options. The processing service is meant to be used for research & development experiments, to support the development contracts awarded confronting the deliverables to ESA, on site demonstrations/training in training courses and workshops, cross-comparison against third party products (CLS/CNES CPP Products for instance), preparation for the Sentinel-3 Topographic mission, producing data and graphics for publications, etc. So far, the processing has been designed and optimized for open ocean studies and is fully functional only over this kind of surface but there are plans to augment this processing capacity over coastal zone, inland water and over land in view of maximizing the exploitation of the upcoming Sentinel-3 Topographic mission over all surfaces. The service is open and free of charge.

Navigation and Remote Sensing Payloads and Methods of the Sarvant Unmanned Aerial System

NASA Astrophysics Data System (ADS)

Molina, P.; Fortuny, P.; Colomina, I.; Remy, M.; Macedo, K. A. C.; Zúnigo, Y. R. C.; Vaz, E.; Luebeck, D.; Moreira, J.; Blázquez, M.

2013-08-01

In a large number of scenarios and missions, the technical, operational and economical advantages of UAS-based photogrammetry and remote sensing over traditional airborne and satellite platforms are apparent. Airborne Synthetic Aperture Radar (SAR) or combined optical/SAR operation in remote areas might be a case of a typical "dull, dirty, dangerous" mission suitable for unmanned operation - in harsh environments such as for example rain forest areas in Brazil, topographic mapping of small to medium sparsely inhabited remote areas with UAS-based photogrammetry and remote sensing seems to be a reasonable paradigm. An example of such a system is the SARVANT platform, a fixed-wing aerial vehicle with a six-meter wingspan and a maximumtake- of-weight of 140 kilograms, able to carry a fifty-kilogram payload. SARVANT includes a multi-band (X and P) interferometric SAR payload, as the P-band enables the topographic mapping of densely tree-covered areas, providing terrain profile information. Moreover, the combination of X- and P-band measurements can be used to extract biomass estimations. Finally, long-term plan entails to incorporate surveying capabilities also at optical bands and deliver real-time imagery to a control station. This paper focuses on the remote-sensing concept in SARVANT, composed by the aforementioned SAR sensor and envisioning a double optical camera configuration to cover the visible and the near-infrared spectrum. The flexibility on the optical payload election, ranging from professional, medium-format cameras to mass-market, small-format cameras, is discussed as a driver in the SARVANT development. The paper also focuses on the navigation and orientation payloads, including the sensors (IMU and GNSS), the measurement acquisition system and the proposed navigation and orientation methods. The latter includes the Fast AT procedure, which performs close to traditional Integrated Sensor Orientation (ISO) and better than Direct Sensor Orientation (DiSO), and features the advantage of not requiring the massive image processing load for the generation of tie points, although it does require some Ground Control Points (GCPs). This technique is further supported by the availability of a high quality INS/GNSS trajectory, motivated by single-pass and repeat-pass SAR interferometry requirements.

Rapid SAR and GPS Measurements and Models for Hazard Science and Situational Awareness

NASA Astrophysics Data System (ADS)

Owen, S. E.; Yun, S. H.; Hua, H.; Agram, P. S.; Liu, Z.; Moore, A. W.; Rosen, P. A.; Simons, M.; Webb, F.; Linick, J.; Fielding, E. J.; Lundgren, P.; Sacco, G. F.; Polet, J.; Manipon, G.

2016-12-01

The Advanced Rapid Imaging and Analysis (ARIA) project for Natural Hazards is focused on rapidly generating higher level geodetic imaging products and placing them in the hands of the solid earth science and local, national, and international natural hazard communities by providing science product generation, exploration, and delivery capabilities at an operational level. Space-based geodetic measurement techniques such as Interferometric Synthetic Aperture Radar (InSAR), Differential Global Positioning System (DGPS), SAR-based change detection, and image pixel tracking have recently become critical additions to our toolset for understanding and mapping the damage caused by earthquakes, volcanic eruptions, landslides, and floods. Analyses of these data sets are still largely handcrafted following each event and are not generated rapidly and reliably enough for response to natural disasters or for timely analysis of large data sets. The ARIA project, a joint venture co-sponsored by California Institute of Technology (Caltech) and by NASA through the Jet Propulsion Laboratory (JPL), has been capturing the knowledge applied to these responses and building it into an automated infrastructure to generate imaging products in near real-time that can improve situational awareness for disaster response. In addition, the ARIA project is developing the capabilities to provide automated imaging and analysis capabilities necessary to keep up with the imminent increase in raw data from geodetic imaging missions planned for launch by NASA, as well as international space agencies. We will present the progress we have made on automating the analysis of SAR data for hazard monitoring and response using data from Sentinel 1a/b as well as continuous GPS stations. Since the beginning of our project, our team has imaged events and generated response products for events around the world. These response products have enabled many conversations with those in the disaster response community about the potential usefulness of rapid SAR and GPS-based information. We will present progress on our data system technology that enables rapid and reliable production of imagery, as well as lessons learned from our engagement with FEMA and others in the hazard response community on the important actionable information that they need.

InSAR and GPS Time Series Analysis in Areas with Large Scale Hydrological Deformation: Separating Signal From Noise at Varying Length Scales in the San Joaquin Valley

NASA Astrophysics Data System (ADS)

Murray, K. D.; Lohman, R.

2017-12-01

Areas of large-scale subsidence are observed over much of the San Joaquin Valley of California due to the extraction of groundwater and hydrocarbons from the subsurface.These signals span regions with spatial extents of up to 100 km and have rates of up to 45 cm/yr or more. InSAR and GPS are complementary methods commonly used to measure such ground displacements and can provide important constraints on crustal deformation models, support groundwater studies, and inform water resource management efforts. However, current standard methods for processing these data sets and creating displacement time series are suboptimal for the deformation observed in areas like the San Joaquin Valley because (1) the ground surface properties are constantly changing due largely to agricultural activity, resulting in low coherence in half or more of a SAR frame, and (2) the deformation signals are distributed throughout the SAR frames, and are comparable to the size of the frames themselves. Therefore, referencing areas of deformation to non-deforming areas and correcting for long wavelength signals (e.g. atmospheric delays, orbital errors) is particularly difficult. We address these challenges by exploiting pixels that are stable in space and time, and use them for weighted spatial averaging and selective filtering before unwrapping. We then compare a range of methods for both long wavelength corrections and referencing via automatic partitioning of non-deforming areas, then benchmark results against continuous GPS measurements. Our final time series consist of nearly 15 years of displacement measurements from continuous GPS data, and Envisat, ALOS-1, Sentinel SAR data, and show significant temporal and spatial variations. We find that the choice of reference and long wavelength corrections can significantly bias long-term rate and seasonal amplitude estimates, causing variations of as much as 100% of the mean estimate. As we enter an era with free and open data access and regular observations plans from missions such as NISAR and the Sentinel constellation, our approach will help users evaluate the significance of observed deformation at a range of spatial scales and in areas with challenging surface properties.

InSAR Time Series Analysis and Geophysical Modeling of City Uplift Associated with Geothermal Drillings in Staufen im Breisgau, Germany

NASA Astrophysics Data System (ADS)

Motagh, M.; Lubitz, C.

2014-12-01

Geothermal energy is of increasing importance as alternative, environmentally friendly technology for heat management. Direct interaction with the subsurface requires careful implementation, in particular in geological complex regions. The historical city Staufen im Breisgau, SW Germany, has attracted national attention as a case of implementation failure with severe consequences, causing debates on the applicability and security of this sustainable technique. Located at the eastern transition zone of the Upper Rhine Graben and the Schwarzwald massif, the geothermal potential is high at Staufen due to strong temperature gradients. In September 2007, seven boreholes for geothermal probes were drilled up to a depth of 140 m to provide a new heat management for the city hall. Within five years an uplift phenomenon has been observed in Staufen reaching more than 40 cm in places and 269 buildings were damaged. Hydro-chemical driven anhydrite-gypsum transformation in the subsurface was identified as the cause leading to volume increase that is observable as surface uplift. This process is associated with the geothermal drilling activities that have crossed several groundwater levels. In this work, we summarize and present the findings of spaceborne Synthetic Aperture Radar Interferometry (InSAR) analysis of the uplift in Staufen over the last five years from July 2008 through July 2013. By applying the Small Baseline Subset (SBAS) method, we find a localized elliptical-shaped deformation field in NE-SW orientation. Area of maximum uplift is located 50 m NNE of the drilling zone. At this location, we observe a cumulative uplift of approx. 13.7 cm ± 0.34 cm (mean value within an area of 30 m by 30 m) from July 2008 to July 2009, which reduced to cumulative uplift of 3 cm ± 0.25 cm from July 2012 to July 2013. The deceleration can be related to applied countermeasures as borehole sealing and groundwater pumping. The observed ground surface response was compared to regularly performed leveling measurements and shows indications of significant symmetric horizontal motions, which were further investigated by a combined analysis of SAR imagery from ascending and descending orbits. Moreover, InSAR observations were inverted using geophysical models to derive first order characteristics of deformation source at depth.

Long-term safety assessment of trench-type surface repository at Chernobyl, Ukraine - computer model and comparison with results from simplified models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haverkamp, B.; Krone, J.; Shybetskyi, I.

2013-07-01

The Radioactive Waste Disposal Facility (RWDF) Buryakovka was constructed in 1986 as part of the intervention measures after the accident at Chernobyl NPP (ChNPP). Today, the surface repository for solid low and intermediate level waste (LILW) is still being operated but its maximum capacity is nearly reached. Long-existing plans for increasing the capacity of the facility shall be implemented in the framework of the European Commission INSC Programme (Instrument for Nuclear Safety Co-operation). Within the first phase of this project, DBE Technology GmbH prepared a safety analysis report of the facility in its current state (SAR) and a preliminary safetymore » analysis report (PSAR) for a future extended facility based on the planned enlargement. In addition to a detailed mathematical model, also simplified models have been developed to verify results of the former one and enhance confidence in the results. Comparison of the results show that - depending on the boundary conditions - simplifications like modeling the multi trench repository as one generic trench might have very limited influence on the overall results compared to the general uncertainties associated with respective long-term calculations. In addition to their value in regard to verification of more complex models which is important to increase confidence in the overall results, such simplified models can also offer the possibility to carry out time consuming calculations like probabilistic calculations or detailed sensitivity analysis in an economic manner. (authors)« less

A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array—Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique

PubMed Central

Li, Bingyi; Chen, Liang; Wei, Chunpeng; Xie, Yizhuang; Chen, He; Yu, Wenyue

2017-01-01

With the development of satellite load technology and very large scale integrated (VLSI) circuit technology, onboard real-time synthetic aperture radar (SAR) imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS) SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT), which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array—application-specific integrated circuit (FPGA-ASIC) hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS) technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384. PMID:28672813

Antenna modeling considerations for accurate SAR calculations in human phantoms in close proximity to GSM cellular base station antennas.

PubMed

van Wyk, Marnus J; Bingle, Marianne; Meyer, Frans J C

2005-09-01

International bodies such as International Commission on Non-Ionizing Radiation Protection (ICNIRP) and the Institute for Electrical and Electronic Engineering (IEEE) make provision for human exposure assessment based on SAR calculations (or measurements) and basic restrictions. In the case of base station exposure this is mostly applicable to occupational exposure scenarios in the very near field of these antennas where the conservative reference level criteria could be unnecessarily restrictive. This study presents a variety of critical aspects that need to be considered when calculating SAR in a human body close to a mobile phone base station antenna. A hybrid FEM/MoM technique is proposed as a suitable numerical method to obtain accurate results. The verification of the FEM/MoM implementation has been presented in a previous publication; the focus of this study is an investigation into the detail that must be included in a numerical model of the antenna, to accurately represent the real-world scenario. This is accomplished by comparing numerical results to measurements for a generic GSM base station antenna and appropriate, representative canonical and human phantoms. The results show that it is critical to take the disturbance effect of the human phantom (a large conductive body) on the base station antenna into account when the antenna-phantom spacing is less than 300 mm. For these small spacings, the antenna structure must be modeled in detail. The conclusion is that it is feasible to calculate, using the proposed techniques and methodology, accurate occupational compliance zones around base station antennas based on a SAR profile and basic restriction guidelines. (c) 2005 Wiley-Liss, Inc.

Design and dosimetric analysis of a 385 MHz TETRA head exposure system for use in human provocation studies.

PubMed

Schmid, Gernot; Bolz, Thomas; Uberbacher, Richard; Escorihuela-Navarro, Ana; Bahr, Achim; Dorn, Hans; Sauter, Cornelia; Eggert, Torsten; Danker-Hopfe, Heidi

2012-10-01

A new head exposure system for double-blind provocation studies investigating possible effects of terrestrial trunked radio (TETRA)-like exposure (385 MHz) on central nervous processes was developed and dosimetrically analyzed. The exposure system allows localized exposure in the temporal brain, similar to the case of operating a TETRA handset at the ear. The system and antenna concept enables exposure during wake and sleep states while an electroencephalogram (EEG) is recorded. The dosimetric assessment and uncertainty analysis yield high efficiency of 14 W/kg per Watt of accepted antenna input power due to an optimized antenna directly worn on the subject's head. Beside sham exposure, high and low exposure at 6 and 1.5 W/kg (in terms of maxSAR10g in the head) were implemented. Double-blind control and monitoring of exposure is enabled by easy-to-use control software. Exposure uncertainty was rigorously evaluated using finite-difference time-domain (FDTD)-based computations, taking into account anatomical differences of the head, the physiological range of the dielectric tissue properties including effects of sweating on the antenna, possible influences of the EEG electrodes and cables, variations in antenna input reflection coefficients, and effects on the specific absorption rate (SAR) distribution due to unavoidable small variations in the antenna position. This analysis yielded a reasonable uncertainty of <±45% (max to min ratio of 4.2 dB) in terms of maxSAR10g in the head and a variability of <±60% (max to min ratio of 6 dB) in terms of mass-averaged SAR in different brain regions, as demonstrated by a brain region-specific absorption analysis. Copyright © 2012 Wiley Periodicals, Inc.

Near-Real-Time Monitoring and Reporting of Crop Growth Condition and Harvest Status Using an Integrated Optical and Radar Approach at the National-Scale in Canada

NASA Astrophysics Data System (ADS)

Shang, J.

2015-12-01

There has been an increasing need to have accurate and spatially detailed information on crop growth condition and harvest status over Canada's agricultural land so that the impacts of environmental conditions, market supply and demand, and transportation network limitations on crop production can be understood fully and acted upon in a timely manner. Presently, Canada doesn't have a national dataset that can provide near-real-time geospatial information on crop growth stage and harvest systematically so that reporting on risk events can be linked directly to the grain supply chain and crop production fluctuations. The intent of this study is to develop an integrated approach using Earth observation (EO) technology to provide a consistent, comprehensive picture of crop growth cycles (growth conditions and stages) and agricultural management activities (field preparation for seeding, harvest, and residue management). Integration of the optical and microwave satellite remote sensing technologies is imperative for robust methodology development and eventually for operational implementation. Particularly, the current synthetic aperture radar (SAR) system Radarsat-2 and to be launched Radarsat Constellation Mission (RCM) are unique EO resources to Canada. Incorporating these Canadian SAR resources with international SAR missions such as the Cosmesky-Med and TerraSAR, could be of great potential for developing change detection technologies particularly useful for monitoring harvest as well as other types of agricultural management events. The study revealed that radar and multi-scale (30m and 250m) optical satellite data can directly detect or infer 1) seeding date, 2) crop growth stages and gross primary productivity (GPP), and 3) harvest progress. Operational prototypes for providing growing-season information at the crop-specific level will be developed across the Canadian agricultural land base.

Pulsed ion beam surface analysis as a means of [ital in] [ital situ] real-time analysis of thin films during growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krauss, A.R.; Lin, Y.; Auciello, O.

1994-07-01

Low-energy (5--15 keV) pulsed ion beam surface analysis comprises several different surface spectroscopies which possess the ability to provide a remarkably wide range of information directly relevant to the growth of single and multicomponent semiconductor, metal and metal-oxide thin films and layered structures. Ion beam methods have not however, been widely used as an [ital in] [ital situ] monitor of thin film growth because existing commercial instrumentation causes excessive film damage, physically conflicts with the deposition equipment, and requires a chamber pressure [similar to]10[sup [minus]7]--10[sup [minus]8] Torr, i.e., much lower than that associated with most deposition processes ([ge]10[sup [minus]4] Torr).more » We have developed time-of-flight ion scattering and recoil spectroscopy (TOF-SARS) as a nondestructive, [ital in] [ital situ], real-time probe of thin film composition and structure which does not physically interfere with the deposition process. Several TOF-SARS implementations are exceptionally surface specific, yet in a properly designed system can yield high-resolution data at ambient pressures well in excess of 10 mTorr (4--6 orders of magnitude higher than conventional surface analytic methods). Because of the exceptional surface specificity of these methods, TOF-SARS is ideally suited as a means of studying ultrathin layers and atomically abrupt interfaces. TOF-SARS instrumentation designed specifically for use as an [ital in] [ital situ], real-time monitor of growth processes for single and multicomponent thin films and layered structures is described here. Representative data are shown for [ital in] [ital situ] analysis of Pb and Zr layers at room temperature and high vacuum, as well as under conditions appropriate to the growth of Pb(Zr[sub [ital x

The Safety project: Sentinel-1 for Civil Protection geohazars management

NASA Astrophysics Data System (ADS)

Monserrat, Oriol; Herrera, Gerardo; Bianchini, Silvia; González-Alonso, Elena; Onori, Roberta; Reichenbach, Paola; Carralero, Innocente P.; Barra, Anna; María Mateos, Rosa; Solari, Lorenzo; Ligüérzana, Sergio; Pagliara, Paola; Ardizzone, Francesca; Sarro, Roberto; Crosetto, Michele; Béjar-Pizarro, Marta; Moretti, Sandro; Lopez, Carmen; Garcia-Cañada, Laura; Benito-Saz, María Á.

2017-04-01

This work is aimed at presenting the ongoing project SAFETY (Sentinel for Geohazards regional monitoring and forecasting). The use of Differential SAR Interferometry (DInSAR) in Natural Risks management is becoming more and more exploitable thanks to the experienced growth of the techniques. On one hand, since the DInSAR technique was proposed for the first time (1989) a wide number of data processing, analysis tools and methods have been developed, on the other hand the satellite data availability has increased and provides sensors with different characteristics of sensitivity and spatial and temporal resolutions. Nowadays, DInSAR allows to have a systematic overview about the spatio-temporal activity of a natural deformation phenomena, which is an important information for the risk management in terms of prevention, emergency response and post-emergency intervention. Specifically, Sentinel-1 (A and B) satellites data show two favourable characteristics: the wide covered area and the short revisit time (6 days). The last one, if compared with the other C band available sensors, results in a reduced temporal decorrelation, particularly in non-urbanized areas, in more robust processing results (due to the higher number of images) and in an higher temporal sampling i.e. a better monitoring and activity characterization. In this context, the European project SAFETY is focused on developing tools and implementing a methodology in order to better exploit Sentinel-1 data in the Civil Protection activities of natural risks prevention. The project is aimed at providing Civil Protection Authorities (CPA) with the capability of periodically evaluating and assessing the potential impact of geohazards (volcanic activity, earthquakes, landslides and subsidence) on urban areas. The first results over the two test-areas in Spain and Italy (respectively Canary Islands and Volterra Municipality) will be presented.

A Spaceborne Synthetic Aperture Radar Partial Fixed-Point Imaging System Using a Field- Programmable Gate Array-Application-Specific Integrated Circuit Hybrid Heterogeneous Parallel Acceleration Technique.

PubMed

Yang, Chen; Li, Bingyi; Chen, Liang; Wei, Chunpeng; Xie, Yizhuang; Chen, He; Yu, Wenyue

2017-06-24

With the development of satellite load technology and very large scale integrated (VLSI) circuit technology, onboard real-time synthetic aperture radar (SAR) imaging systems have become a solution for allowing rapid response to disasters. A key goal of the onboard SAR imaging system design is to achieve high real-time processing performance with severe size, weight, and power consumption constraints. In this paper, we analyse the computational burden of the commonly used chirp scaling (CS) SAR imaging algorithm. To reduce the system hardware cost, we propose a partial fixed-point processing scheme. The fast Fourier transform (FFT), which is the most computation-sensitive operation in the CS algorithm, is processed with fixed-point, while other operations are processed with single precision floating-point. With the proposed fixed-point processing error propagation model, the fixed-point processing word length is determined. The fidelity and accuracy relative to conventional ground-based software processors is verified by evaluating both the point target imaging quality and the actual scene imaging quality. As a proof of concept, a field- programmable gate array-application-specific integrated circuit (FPGA-ASIC) hybrid heterogeneous parallel accelerating architecture is designed and realized. The customized fixed-point FFT is implemented using the 130 nm complementary metal oxide semiconductor (CMOS) technology as a co-processor of the Xilinx xc6vlx760t FPGA. A single processing board requires 12 s and consumes 21 W to focus a 50-km swath width, 5-m resolution stripmap SAR raw data with a granularity of 16,384 × 16,384.

Land Subsidence Monitoring by InSAR Time Series Technique Derived From ALOS-2 PALSAR-2 over Surabaya City, Indonesia

NASA Astrophysics Data System (ADS)

Aditiya, A.; Takeuchi, W.; Aoki, Y.

2017-12-01

Surabaya is the second largest city in Indonesia and the capital of East Java Province with rapid population and industrialization. The impact of urbanization in the big city can suffer potential disasters either nature or anthropogenic such as land subsidence and flood. The pattern of land subsidence need to be mapped for the purposes of planning and structuring the city as well as taking appropriate policy in anticipating and mitigating the impact. This research has used interferometric Synthetic Aperture Radar (InSAR) Small Baseline Subset (SBAS) technique and applied time series analysis to investigate land subsidence occured. The technique includes the process of focusing the SAR data, incorporating the precise orbit, generating interferogram and phase unwrapping using SNAPHU algorithms. The results showed land subsidence has been detected during 2014-2017 over Surabaya city area using ALOS-2/PALSAR-2 images data. These results reveal the subsidence has observed in several area in Surabaya in particular northern part reach up to ∼2 cm/year. The fastest subsidence occurs in highly populated areas suffer vulnerable to flooding and sea level rise impact. In urban areas we found a correlation between land subsidence with residential or industrial land use. It concludes that land subsidence is mainly caused by ground water consumption for industrial and residential use respectively.

Sentinel-1 data exploitation for geohazard activity map generation

NASA Astrophysics Data System (ADS)

Barra, Anna; Solari, Lorenzo; Béjar-Pizarro, Marta; Monserrat, Oriol; Herrera, Gerardo; Bianchini, Silvia; Crosetto, Michele; María Mateos, Rosa; Sarro, Roberto; Moretti, Sandro

2017-04-01

This work is focused on geohazard mapping and monitoring by exploiting Sentinel-1 (A and B) data and the DInSAR (Differential interferometric SAR (Synthetic Aperture Radar)) techniques. Sometimes the interpretation of the DInSAR derived product (like the velocity map) can be complex, mostly for a final user who do not usually works with radar. The aim of this work is to generate, in a rapid way, a clear product to be easily exploited by the authorities in the geohazard management: intervention planning and prevention activities. Specifically, the presented methodology has been developed in the framework of the European project SAFETY, which is aimed at providing Civil Protection Authorities (CPA) with the capability of periodically evaluating and assessing the potential impact of geohazards (volcanic activity, earthquakes, landslides and subsidence) on urban areas. The methodology has three phases, the interferograms generation, the activity map generation, in terms of velocity and accumulated deformation (with time-series), and the Active Deformation Area (ADA) map generation. The last one is the final product, derived from the original activity map by analyzing the data in a Geographic Information System (GIS) environment, which isolate only the true deformation areas over the noise. This product can be more easily read by the authorities than the original activity map, i.e. can be better exploited to integrate other information and analysis. This product also permit an easy monitoring of the active areas.

Petascale Simulation Initiative Tech Base: FY2007 Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

May, J; Chen, R; Jefferson, D

The Petascale Simulation Initiative began as an LDRD project in the middle of Fiscal Year 2004. The goal of the project was to develop techniques to allow large-scale scientific simulation applications to better exploit the massive parallelism that will come with computers running at petaflops per second. One of the major products of this work was the design and prototype implementation of a programming model and a runtime system that lets applications extend data-parallel applications to use task parallelism. By adopting task parallelism, applications can use processing resources more flexibly, exploit multiple forms of parallelism, and support more sophisticated multiscalemore » and multiphysics models. Our programming model was originally called the Symponents Architecture but is now known as Cooperative Parallelism, and the runtime software that supports it is called Coop. (However, we sometimes refer to the programming model as Coop for brevity.) We have documented the programming model and runtime system in a submitted conference paper [1]. This report focuses on the specific accomplishments of the Cooperative Parallelism project (as we now call it) under Tech Base funding in FY2007. Development and implementation of the model under LDRD funding alone proceeded to the point of demonstrating a large-scale materials modeling application using Coop on more than 1300 processors by the end of FY2006. Beginning in FY2007, the project received funding from both LDRD and the Computation Directorate Tech Base program. Later in the year, after the three-year term of the LDRD funding ended, the ASC program supported the project with additional funds. The goal of the Tech Base effort was to bring Coop from a prototype to a production-ready system that a variety of LLNL users could work with. Specifically, the major tasks that we planned for the project were: (1) Port SARS [former name of the Coop runtime system] to another LLNL platform, probably Thunder or Peloton (depending on when Peloton becomes available); (2) Improve SARS's robustness and ease-of-use, and develop user documentation; and (3) Work with LLNL code teams to help them determine how Symponents could benefit their applications. The original funding request was $296,000 for the year, and we eventually received $252,000. The remainder of this report describes our efforts and accomplishments for each of the goals listed above.« less

Damage Proxy Map from InSAR Coherence Applied to February 2011 M6.3 Christchurch Earthquake, 2011 M9.0 Tohoku-oki Earthquake, and 2011 Kirishima Volcano Eruption

NASA Astrophysics Data System (ADS)

Yun, S.; Agram, P. S.; Fielding, E. J.; Simons, M.; Webb, F.; Tanaka, A.; Lundgren, P.; Owen, S. E.; Rosen, P. A.; Hensley, S.

2011-12-01

Under ARIA (Advanced Rapid Imaging and Analysis) project at JPL and Caltech, we developed a prototype algorithm to detect surface property change caused by natural or man-made damage using InSAR coherence change. The algorithm was tested on building demolition and construction sites in downtown Pasadena, California. The developed algorithm performed significantly better, producing 150 % higher signal-to-noise ratio, than a standard coherence change detection method. We applied the algorithm to February 2011 M6.3 Christchurch earthquake in New Zealand, 2011 M9.0 Tohoku-oki earthquake in Japan, and 2011 Kirishima volcano eruption in Kyushu, Japan, using ALOS PALSAR data. In Christchurch area we detected three different types of damage: liquefaction, building collapse, and landslide. The detected liquefaction damage is extensive in the eastern suburbs of Christchurch, showing Bexley as one of the most significantly affected areas as was reported in the media. Some places show sharp boundaries of liquefaction damage, indicating different type of ground materials that might have been formed by the meandering Avon River in the past. Well reported damaged buildings such as Christchurch Cathedral, Canterbury TV building, Pyne Gould building, and Cathedral of the Blessed Sacrament were detected by the algorithm. A landslide in Redcliffs was also clearly detected. These detected damage sites were confirmed with Google earth images provided by GeoEye. Larger-scale damage pattern also agrees well with the ground truth damage assessment map indicated with polygonal zones of 3 different damage levels, compiled by the government of New Zealand. The damage proxy map of Sendai area in Japan shows man-made structure damage due to the tsunami caused by the M9.0 Tohoku-oki earthquake. Long temporal baseline (~2.7 years) and volume scattering caused significant decorrelation in the farmlands and bush forest along the coastline. The 2011 Kirishima volcano eruption caused a lot of ash fall deposit in the southeast from the volcano. The detected ash fall damage area exactly matches the in-situ measurements implemented through fieldwork by Geological Survey of Japan. With 99-percentile threshold for damage detection, the periphery of the detected damage area aligns with a contour line of 100 kg/m2 ash deposit, equivalent to 10 cm of depth assuming a density of 1000 kg/m3 for the ash layer. With growing number of InSAR missions, rapidly produced accurate damage assessment maps will help save people, assisting effective prioritization of rescue operations at early stage of response, and significantly improve timely situational awareness for emergency management and national / international assessment and response for recovery planning. Results of this study will also inform the design of future InSAR missions including the proposed DESDynI.

Antibody-dependent SARS coronavirus infection is mediated by antibodies against spike proteins.

PubMed

Wang, Sheng-Fan; Tseng, Sung-Pin; Yen, Chia-Hung; Yang, Jyh-Yuan; Tsao, Ching-Han; Shen, Chun-Wei; Chen, Kuan-Hsuan; Liu, Fu-Tong; Liu, Wu-Tse; Chen, Yi-Ming Arthur; Huang, Jason C

2014-08-22

The severe acute respiratory syndrome coronavirus (SARS-CoV) still carries the potential for reemergence, therefore efforts are being made to create a vaccine as a prophylactic strategy for control and prevention. Antibody-dependent enhancement (ADE) is a mechanism through which dengue viruses, feline coronaviruses, and HIV viruses take advantage of anti-viral humoral immune responses to infect host target cells. Here we describe our observations of SARS-CoV using ADE to enhance the infectivity of a HL-CZ human promonocyte cell line. Quantitative-PCR and immunofluorescence staining results indicate that SARS-CoV is capable of replication in HL-CZ cells, and of displaying virus-induced cytopathic effects and increased levels of TNF-α, IL-4 and IL-6 two days post-infection. According to flow cytometry data, the HL-CZ cells also expressed angiotensin converting enzyme 2 (ACE2, a SARS-CoV receptor) and higher levels of the FcγRII receptor. We found that higher concentrations of anti-sera against SARS-CoV neutralized SARS-CoV infection, while highly diluted anti-sera significantly increased SARS-CoV infection and induced higher levels of apoptosis. Results from infectivity assays indicate that SARS-CoV ADE is primarily mediated by diluted antibodies against envelope spike proteins rather than nucleocapsid proteins. We also generated monoclonal antibodies against SARS-CoV spike proteins and observed that most of them promoted SARS-CoV infection. Combined, our results suggest that antibodies against SARS-CoV spike proteins may trigger ADE effects. The data raise new questions regarding a potential SARS-CoV vaccine, while shedding light on mechanisms involved in SARS pathogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

Advanced Techniques for Scene Analysis

DTIC Science & Technology

2010-06-01

robustness prefers a bigger intergration window to handle larger motions. The advantage of pyramidal implementation is that, while each motion vector dL...labeled SAR images. Now the previous algorithm leads to a more dedicated classifier for the particular target; however, our algorithm trades generality for...accuracy is traded for generality. 7.3.2 I-RELIEF Feature weighting transforms the original feature vector x into a new feature vector x′ by assigning each

Implementing Effective Affordability Constraints for Defense Acquisition Programs

DTIC Science & Technology

2014-03-01

interviewees reported that they could recall no instances when establishing or exceeding DTC goals was a topic of high -level deliberations. Review of...attention of high -level management for several years. Unlike, DTC, however, CAIV cost objectives were never systematically recorded in SARs, and for that...systems. The uncertainty can be expected to decrease as systems mature; however, it will still be high at least until the system completes initial

Functional Flow and Event-Driven Methods for Predicting System Performance

DTIC Science & Technology

2015-09-01

The thesis process was difficult and at times painful , but the modeling applications were something that I thoroughly enjoyed working through and...21. 2. SAR Mission initiates; SAR Assets conduct search but no objects of interest are found; SAR assets continue to scan but OSC aborts mission...be related to the SAR, so the OSC aborts mission and all Assets RTB. 45 4. SAR Mission initiates; SAR Assets conduct search and find an object of

JPL Researcher Bruce Chapman at an AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign

NASA Image and Video Library

2004-03-03

JPL Researcher Bruce Chapman at an AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

Local SAR in High Pass Birdcage and TEM Body Coils for Multiple Human Body Models in Clinical Landmark Positions at 3T

PubMed Central

Yeo, Desmond TB; Wang, Zhangwei; Loew, Wolfgang; Vogel, Mika W; Hancu, Ileana

2011-01-01

Purpose To use EM simulations to study the effects of body type, landmark position, and RF body coil type on peak local SAR in 3T MRI. Materials and Methods Numerically computed peak local SAR for four human body models (HBMs) in three landmark positions (head, heart, pelvic) were compared for a high-pass birdcage and a transverse electromagnetic 3T body coil. Local SAR values were normalized to the IEC whole-body average SAR limit of 2.0 W/kg for normal scan mode. Results Local SAR distributions were highly variable. Consistent with previous reports, the peak local SAR values generally occurred in the neck-shoulder area, near rungs, or between tissues of greatly differing electrical properties. The HBM type significantly influenced the peak local SAR, with stockier HBMs, extending extremities towards rungs, displaying the highest SAR. There was also a trend for higher peak SAR in the head-centric and heart-centric positions. The impact of the coil-types studied was not statistically significant. Conclusion The large variability in peak local SAR indicates the need to include more than one HBM or landmark position when evaluating safety of body coils. It is recommended that a HBM with arms near the rungs be included, to create physically realizable high-SAR scenarios. PMID:21509880

Computerized ionospheric tomography based on geosynchronous SAR

NASA Astrophysics Data System (ADS)

Hu, Cheng; Tian, Ye; Dong, Xichao; Wang, Rui; Long, Teng

2017-02-01

Computerized ionospheric tomography (CIT) based on spaceborne synthetic aperture radar (SAR) is an emerging technique to construct the three-dimensional (3-D) image of ionosphere. The current studies are all based on the Low Earth Orbit synthetic aperture radar (LEO SAR) which is limited by long repeat period and small coverage. In this paper, a novel ionospheric 3-D CIT technique based on geosynchronous SAR (GEO SAR) is put forward. First, several influences of complex atmospheric environment on GEO SAR focusing are detailedly analyzed, including background ionosphere and multiple scattering effects (induced by turbulent ionosphere), tropospheric effects, and random noises. Then the corresponding GEO SAR signal model is constructed with consideration of the temporal-variant background ionosphere within the GEO SAR long integration time (typically 100 s to 1000 s level). Concurrently, an accurate total electron content (TEC) retrieval method based on GEO SAR data is put forward through subband division in range and subaperture division in azimuth, obtaining variant TEC value with respect to the azimuth time. The processing steps of GEO SAR CIT are given and discussed. Owing to the short repeat period and large coverage area, GEO SAR CIT has potentials of covering the specific space continuously and completely and resultantly has excellent real-time performance. Finally, the TEC retrieval and GEO SAR CIT construction are performed by employing a numerical study based on the meteorological data. The feasibility and correctness of the proposed methods are verified.

77 FR 43205 - Notice of Data Availability for Approval, Disapproval and Promulgation of Implementation Plans...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-24

... Haze State Implementation Plan; Federal Implementation Plan for Regional Haze AGENCY: Environmental... (SIP) revision submitted by the State of Wyoming on January 12, 2011, that addresses regional haze...; Regional Haze State Implementation Plan; Federal Implementation Plan for Regional Haze; Proposed Rule (77...

78 FR 28775 - Approval and Promulgation of Implementation Plans; North Carolina; State Implementation Plan...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-16

... Promulgation of Implementation Plans; North Carolina; State Implementation Plan Miscellaneous Revisions AGENCY... a revision to the North Carolina State Implementation Plan submitted on February 3, 2010, through... particulate matter found in the Code of Federal Regulations. In the Final Rules Section of this Federal...

Terrain Measurement with SAR/InSAR

NASA Astrophysics Data System (ADS)

Li, Deren; Liao, Mingsheng; Balz, Timo; Zhang, Lu; Yang, Tianliang

2016-08-01

Terrain measurement and surface motion estimation are the most important applications for commercial and scientific SAR missions. In Dragon-3, we worked on these applications, especially regarding DEM generation, surface motion estimation with SAR time- series for urban subsidence monitoring and landslide motion estimation, as well as developing tomographic SAR processing methods in urban areas.

Excretion and detection of SARS coronavirus and its nucleic acid from digestive system

PubMed Central

Wang, Xin-Wei; Li, Jin-Song; Guo, Ting-Kai; Zhen, Bei; Kong, Qing-Xin; Yi, Bin; Li, Zhong; Song, Nong; Jin, Min; Wu, Xiao-Ming; Xiao, Wen-Jun; Zhu, Xiu-Mei; Gu, Chang-Qing; Yin, Jing; Wei, Wei; Yao, Wei; Liu, Chao; Li, Jian-Feng; Ou, Guo-Rong; Wang, Min-Nian; Fang, Tong-Yu; Wang, Gui-Jie; Qiu, Yao-Hui; Wu, Huai-Huan; Chao, Fu-Huan; Li, Jun-Wen

2005-01-01

AIM: To study whether severe acute respiratory syndrome coronavirus (SARS-CoV) could be excreted from digestive system. METHODS: Cell culture and semi-nested RT-PCR were used to detect SARS-CoV and its RNA from 21 stool and urine samples, and a kind of electropositive filter media particles was used to concentrate the virus in 10 sewage samples from two hospitals receiving SARS patients in Beijing in China. RESULTS: It was demonstrated that there was no live SARS-CoV in all samples collected, but the RNA of SARS-CoV could be detected in seven stool samples from SARS patients with any one of the symptoms of fever, malaise, cough, or dyspnea, in 10 sewage samples before disinfection and 3 samples after disinfection from the two hospitals. The RNA could not be detected in urine and stool samples from patients recovered from SARS. CONCLUSION: Nucleic acid of SARS-CoV can be excreted through the stool of patients into sewage system, and the possibility of SARS-CoV transmitting through digestive system cannot be excluded. PMID:16038039

Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points - A Review.

PubMed

Zou, Weibao; Li, Yan; Li, Zhilin; Ding, Xiaoli

2009-01-01

Interferometric Synthetic Aperture Radar (InSAR) is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR) images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs) and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram.

Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points – A Review

PubMed Central

Zou, Weibao; Li, Yan; Li, Zhilin; Ding, Xiaoli

2009-01-01

Interferometric Synthetic Aperture Radar (InSAR) is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR) images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs) and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram. PMID:22399966

Identification of Diverse Alphacoronaviruses and Genomic Characterization of a Novel Severe Acute Respiratory Syndrome-Like Coronavirus from Bats in China

PubMed Central

He, Biao; Zhang, Yuzhen; Xu, Lin; Yang, Weihong; Yang, Fanli; Feng, Yun; Xia, Lele; Zhou, Jihua; Zhen, Weibin; Feng, Ye; Guo, Huancheng

2014-01-01

ABSTRACT Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been identified in bats in China, Europe, and Africa, most have a genetic organization significantly distinct from human/civet SARS CoVs in the receptor-binding domain (RBD), which mediates receptor binding and determines the host spectrum, resulting in their failure to cause human infections and making them unlikely progenitors of human/civet SARS CoVs. Here, a viral metagenomic analysis of 268 bat rectal swabs collected from four counties in Yunnan Province has identified hundreds of sequences relating to alpha- and betacoronaviruses. Phylogenetic analysis based on a conserved region of the RNA-dependent RNA polymerase gene revealed that alphacoronaviruses had diversities with some obvious differences from those reported previously. Full genomic analysis of a new SARS-like CoV from Baoshan (LYRa11) showed that it was 29,805 nucleotides (nt) in length with 13 open reading frames (ORFs), sharing 91% nucleotide identity with human/civet SARS CoVs and the most recently reported SARS-like CoV Rs3367, while sharing 89% with other bat SARS-like CoVs. Notably, it showed the highest sequence identity with the S gene of SARS CoVs and Rs3367, especially in the RBD region. Antigenic analysis showed that the S1 domain of LYRa11 could be efficiently recognized by SARS-convalescent human serum, indicating that LYRa11 is a novel virus antigenically close to SARS CoV. Recombination analyses indicate that LYRa11 is likely a recombinant descended from parental lineages that had evolved into a number of bat SARS-like CoVs. IMPORTANCE Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been discovered in bats worldwide, there are significant different genic structures, particularly in the S1 domain, which are responsible for host tropism determination, between bat SARS-like CoVs and human SARS CoVs, indicating that most reported bat SARS-like CoVs are not the progenitors of human SARS CoV. We have identified diverse alphacoronaviruses and a close relative (LYRa11) to SARS CoV in bats collected in Yunnan, China. Further analysis showed that alpha- and betacoronaviruses have different circulation and transmission dynamics in bat populations. Notably, full genomic sequencing and antigenic study demonstrated that LYRa11 is phylogenetically and antigenically closely related to SARS CoV. Recombination analyses indicate that LYRa11 is a recombinant from certain bat SARS-like CoVs circulating in Yunnan Province. PMID:24719429

Severe acute respiratory syndrome (SARS)

MedlinePlus

SARS; Respiratory failure - SARS ... Complications may include: Respiratory failure Liver failure Heart failure ... 366. McIntosh K, Perlman S. Coronaviruses, including severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS). ...

Monitoring Building Deformation with InSAR: Experiments and Validation

PubMed Central

Yang, Kui; Yan, Li; Huang, Guoman; Chen, Chu; Wu, Zhengpeng

2016-01-01

Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated. PMID:27999403

Satellite SAR geocoding with refined RPC model

NASA Astrophysics Data System (ADS)

Zhang, Lu; Balz, Timo; Liao, Mingsheng

2012-04-01

Recent studies have proved that the Rational Polynomial Camera (RPC) model is able to act as a reliable replacement of the rigorous Range-Doppler (RD) model for the geometric processing of satellite SAR datasets. But its capability in absolute geolocation of SAR images has not been evaluated quantitatively. Therefore, in this article the problems of error analysis and refinement of SAR RPC model are primarily investigated to improve the absolute accuracy of SAR geolocation. Range propagation delay and azimuth timing error are identified as two major error sources for SAR geolocation. An approach based on SAR image simulation and real-to-simulated image matching is developed to estimate and correct these two errors. Afterwards a refined RPC model can be built from the error-corrected RD model and then used in satellite SAR geocoding. Three experiments with different settings are designed and conducted to comprehensively evaluate the accuracies of SAR geolocation with both ordinary and refined RPC models. All the experimental results demonstrate that with RPC model refinement the absolute location accuracies of geocoded SAR images can be improved significantly, particularly in Easting direction. In another experiment the computation efficiencies of SAR geocoding with both RD and RPC models are compared quantitatively. The results show that by using the RPC model such efficiency can be remarkably improved by at least 16 times. In addition the problem of DEM data selection for SAR image simulation in RPC model refinement is studied by a comparative experiment. The results reveal that the best choice should be using the proper DEM datasets of spatial resolution comparable to that of the SAR images.

Local SAR in parallel transmission pulse design.

PubMed

Lee, Joonsung; Gebhardt, Matthias; Wald, Lawrence L; Adalsteinsson, Elfar

2012-06-01

The management of local and global power deposition in human subjects (specific absorption rate, SAR) is a fundamental constraint to the application of parallel transmission (pTx) systems. Even though the pTx and single channel have to meet the same SAR requirements, the complex behavior of the spatial distribution of local SAR for transmission arrays poses problems that are not encountered in conventional single-channel systems and places additional requirements on pTx radio frequency pulse design. We propose a pTx pulse design method which builds on recent work to capture the spatial distribution of local SAR in numerical tissue models in a compressed parameterization in order to incorporate local SAR constraints within computation times that accommodate pTx pulse design during an in vivo magnetic resonance imaging scan. Additionally, the algorithm yields a protocol-specific ultimate peak in local SAR, which is shown to bound the achievable peak local SAR for a given excitation profile fidelity. The performance of the approach was demonstrated using a numerical human head model and a 7 Tesla eight-channel transmit array. The method reduced peak local 10 g SAR by 14-66% for slice-selective pTx excitations and 2D selective pTx excitations compared to a pTx pulse design constrained only by global SAR. The primary tradeoff incurred for reducing peak local SAR was an increase in global SAR, up to 34% for the evaluated examples, which is favorable in cases where local SAR constraints dominate the pulse applications. Copyright © 2011 Wiley Periodicals, Inc.

JPL Researcher Tim Miller at the primary AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign

NASA Image and Video Library

2004-03-03

JPL Researcher Tim Miller at the primary AirSAR station aboard NASA's DC-8 flying laboratory during the AirSAR 2004 campaign. AirSAR 2004 is a three-week expedition by an international team of scientists that will use an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR), in a mission ranging from the tropical rain forests of Central America to frigid Antarctica.

Approved Air Quality Implementation Plans in Region 10

EPA Pesticide Factsheets

Landing page for information about EPA-approved air quality State Implementation Plans (SIPs), Tribal Implementation Plans (TIPs), and Federal Implementation Plans (FIPs) in Alaska, Idaho, Oregon, Washington.

78 FR 69625 - Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-20

...] Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision AGENCY...) is proposing to approve a revision to the New York State Implementation Plan (SIP) for ozone... air quality standards for ozone. DATES: Comments must be received on or before December 20, 2013...

77 FR 13974 - Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-08

... Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision AGENCY: Environmental... a proposed revision to the New York State Implementation Plan (SIP) for ozone concerning the control... national ambient air quality standards for ozone. DATES: Effective Date: This rule will be effective April...

Broadview Radar Altimetry Toolbox

NASA Astrophysics Data System (ADS)

Escolà, Roger; Garcia-Mondejar, Albert; Moyano, Gorka; Roca, Mònica; Terra-Homem, Miguel; Friaças, Ana; Martinho, Fernando; Schrama, Ernst; Naeije, Marc; Ambrozio, Americo; Restano, Marco; Benveniste, Jérôme

2016-04-01

The universal altimetry toolbox, BRAT (Broadview Radar Altimetry Toolbox) which can read all previous and current altimetry missions' data, incorporates now the capability to read the upcoming Sentinel-3 L1 and L2 products. ESA endeavoured to develop and supply this capability to support the users of the future Sentinel-3 SAR Altimetry Mission. BRAT is a collection of tools and tutorial documents designed to facilitate the processing of radar altimetry data. This project started in 2005 from the joint efforts of ESA (European Space Agency) and CNES (Centre National d'Etudes Spatiales), and it is freely available at http://earth.esa.int/brat. The tools enable users to interact with the most common altimetry data formats. The BratGUI is the front-end for the powerful command line tools that are part of the BRAT suite. BRAT can also be used in conjunction with MATLAB/IDL (via reading routines) or in C/C++/Fortran via a programming API, allowing the user to obtain desired data, bypassing the data-formatting hassle. BRAT can be used simply to visualise data quickly, or to translate the data into other formats such as NetCDF, ASCII text files, KML (Google Earth) and raster images (JPEG, PNG, etc.). Several kinds of computations can be done within BRAT involving combinations of data fields that the user can save for posterior reuse or using the already embedded formulas that include the standard oceanographic altimetry formulas. The Radar Altimeter Tutorial, that contains a strong introduction to altimetry, shows its applications in different fields such as Oceanography, Cryosphere, Geodesy, Hydrology among others. Included are also "use cases", with step-by-step examples, on how to use the toolbox in the different contexts. The Sentinel-3 SAR Altimetry Toolbox shall benefit from the current BRAT version. While developing the toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and specific "use-cases" for SAR altimetry in order to train the users and make them aware of the great potential of SAR altimetry for coastal and inland applications. As for any open source framework, contributions from users having developed their own functions are welcome. The Broadview Radar Altimetry Toolbox is a continuation of the Basic Radar Altimetry Toolbox. While developing the new toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and specific "use-cases" for SAR altimetry in order to train the users and make them aware of the great potential of SAR altimetry for coastal and inland applications. As for any open source framework, contributions from users having developed their own functions are welcome. The first Release of the new Radar Altimetry Toolbox was published in September 2015. It incorporates the capability to read S3 products as well as the new CryoSat-2 Baseline C. The second Release of the Toolbox, planned for March 2016, will have a new graphical user interface and some visualisation improvements. The third release, planned for September 2016, will incorporate new datasets such as the lake and rivers or the envissat reprocessed, new features regarding data interpolation and formulas updates.

Broadview Radar Altimetry Toolbox

NASA Astrophysics Data System (ADS)

Mondéjar, Albert; Benveniste, Jérôme; Naeije, Marc; Escolà, Roger; Moyano, Gorka; Roca, Mònica; Terra-Homem, Miguel; Friaças, Ana; Martinho, Fernando; Schrama, Ernst; Ambrózio, Américo; Restano, Marco

2016-07-01

The universal altimetry toolbox, BRAT (Broadview Radar Altimetry Toolbox) which can read all previous and current altimetry missions' data, incorporates now the capability to read the upcoming Sentinel-3 L1 and L2 products. ESA endeavoured to develop and supply this capability to support the users of the future Sentinel-3 SAR Altimetry Mission. BRAT is a collection of tools and tutorial documents designed to facilitate the processing of radar altimetry data. This project started in 2005 from the joint efforts of ESA (European Space Agency) and CNES (Centre National d'Études Spatiales), and it is freely available at http://earth.esa.int/brat. The tools enable users to interact with the most common altimetry data formats. The BratGUI is the front-end for the powerful command line tools that are part of the BRAT suite. BRAT can also be used in conjunction with MATLAB/IDL (via reading routines) or in C/C++/Fortran via a programming API, allowing the user to obtain desired data, bypassing the data-formatting hassle. BRAT can be used simply to visualise data quickly, or to translate the data into other formats such as NetCDF, ASCII text files, KML (Google Earth) and raster images (JPEG, PNG, etc.). Several kinds of computations can be done within BRAT involving combinations of data fields that the user can save for posterior reuse or using the already embedded formulas that include the standard oceanographic altimetry formulas. The Radar Altimeter Tutorial, that contains a strong introduction to altimetry, shows its applications in different fields such as Oceanography, Cryosphere, Geodesy, Hydrology among others. Included are also "use cases", with step-by-step examples, on how to use the toolbox in the different contexts. The Sentinel-3 SAR Altimetry Toolbox shall benefit from the current BRAT version. While developing the toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and specific "use-cases" for SAR altimetry in order to train the users and make them aware of the great potential of SAR altimetry for coastal and inland applications. As for any open source framework, contributions from users having developed their own functions are welcome. The Broadview Radar Altimetry Toolbox is a continuation of the Basic Radar Altimetry Toolbox. While developing the new toolbox we will revamp of the Graphical User Interface and provide, among other enhancements, support for reading the upcoming S3 datasets and specific "use-cases" for SAR altimetry in order to train the users and make them aware of the great potential of SAR altimetry for coastal and inland applications. As for any open source framework, contributions from users having developed their own functions are welcome. The first Release of the new Radar Altimetry Toolbox was published in September 2015. It incorporates the capability to read S3 products as well as the new CryoSat-2 Baseline C. The second Release of the Toolbox, planned for March 2016, will have a new graphical user interface and some visualisation improvements. The third release, planned for September 2016, will incorporate new datasets such as the lake and rivers or the EnviSat reprocessed, new features regarding data interpolation and formulas updates.

The Primi Project: August-September 2009 Validation Cruise On Oil Spill Detection And Fate

NASA Astrophysics Data System (ADS)

Santoleri, R.; Bignami, F.; Bohm, E.; Nichio, F.; De Dominicis, M.; Ruggieri, G.; Marulllo, S.; Trivero, P.; Zambianchi, E.; Archetti, R.; Adamo, M.; Biamino, W.; Borasi, M.; Buongiorno Nardelli, B.; Cavagnero, M.; Colao, F.; Colella, S.; Coppini, G.; Debettio, V.; De Carolis, G.; Forneris, V.; Griffa, A.; Iacono, R.; Lombardi, E.; Manzella, G.; Mercantini, A.; Napolitano, E.; Pinardi, N.; Pandiscia, G.; Pisano, A.; Rupolo, V.; Reseghetti, F.; Sabia, L.; Sorgente, R.; Sprovieri, M.; Terranova, G.; Trani, M.; Volpe, G.

2010-04-01

In the framework of the ASI PRIMI Project, CNR- ISAC, in collaboration with the PRIMI partners, organized a validation cruise for the PRIMI oil spill monitoring and forecasting system on board the CNR R/V Urania. The cruise (Aug. 6 - Sept. 7 2009) took place in the Sicily Strait, an area affected by large oil tanker traffic. The cruise plan was organized in order to have the ship within the selected SAR image frames at acquisition time so that the ship could move toward the oil slick and verify it via visual and instrumental inspection. During the cruise, several oil spills, presumably being the result of illegal tank washing, were detected by the PRIMI system and were verified in situ. Preliminary results indicate that SAR and optical satellites are able to detect heavy and thin film oil spills, the maturity of oil spill forecasting models and that further work combining satellite, model and in situ data is necessary to assess the spill severity from the signature in satellite imagery.

Report on SARS backfit evaluation, Catalytic, Inc. Solvent Refined Coal Pilot Plant, Wilsonville, Alabama

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, A.F. Jr.

1980-07-02

A site visit was made in company with the DOE-OPTA-EA Safety and Health Official for the purpose of providing that official with technical assistance in evaluating the validity of an earlier DOE-OPTA recommendation exempting this facility from the Safety and Analysis and Review backfit requirements of DOE Order 5481.1. A further purpose of the visit was to assess and evaluate the occupational safety and health program at this facility, as compared with the criteria and guidelines contained in ASFE Order 5481.1. Adequate documentation regarding compliance with codes, standards, and regulations were observed at this facility. There is in existence anmore » ongoing continuous safety analysis effort for both modifications or additions to this facility. Adequate environmental safeguards and plans and procedures were observed. The SARS backfit exemption is appropriate. The occupational safety and health program is in many ways a model for the scope of work and nature of hazards involved, and is consistent with ASFE guidelines and statutory requirements.« less

Low Latency DESDynI Data Products for Disaster Response, Resource Management and Other Applications

NASA Technical Reports Server (NTRS)

Doubleday, Joshua R.; Chien, Steve A.; Lou, Yunling

2011-01-01

We are developing onboard processor technology targeted at the L-band SAR instrument onboard the planned DESDynI mission to enable formation of SAR images onboard opening possibilities for near-real-time data products to augment full data streams. Several image processing and/or interpretation techniques are being explored as possible direct-broadcast products for use by agencies in need of low-latency data, responsible for disaster mitigation and assessment, resource management, agricultural development, shipping, etc. Data collected through UAVSAR (L-band) serves as surrogate to the future DESDynI instrument. We have explored surface water extent as a tool for flooding response, and disturbance images on polarimetric backscatter of repeat pass imagery potentially useful for structural collapse (earthquake), mud/land/debris-slides etc. We have also explored building vegetation and snow/ice classifiers, via support vector machines utilizing quad-pol backscatter, cross-pol phase, and a number of derivatives (radar vegetation index, dielectric estimates, etc.). We share our qualitative and quantitative results thus far.

Temperature distribution analysis of tissue water vaporization during microwave ablation: experiments and simulations.

PubMed

Ai, Haiming; Wu, Shuicai; Gao, Hongjian; Zhao, Lei; Yang, Chunlan; Zeng, Yi

2012-01-01

The temperature distribution in the region near a microwave antenna is a critical factor that affects the entire temperature field during microwave ablation of tissue. It is challenging to predict this distribution precisely, because the temperature in the near-antenna region varies greatly. The effects of water vaporisation and subsequent tissue carbonisation in an ex vivo porcine liver were therefore studied experimentally and in simulations. The enthalpy and high-temperature specific absorption rate (SAR) of liver tissues were calculated and incorporated into the simulation process. The accuracy of predictions for near-field temperatures in our simulations has reached the level where the average maximum error is less than 5°C. In addition, a modified thermal model that accounts for water vaporisation and the change in the SAR distribution pattern is proposed and validated with experiment. The results from this study may be useful in the clinical practice of microwave ablation and can be applied to predict the temperature field in surgical planning.

Radar transponder apparatus and signal processing technique

DOEpatents

Axline, Jr., Robert M.; Sloan, George R.; Spalding, Richard E.

1996-01-01

An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder's echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR.

Radar transponder apparatus and signal processing technique

DOEpatents

Axline, R.M. Jr.; Sloan, G.R.; Spalding, R.E.

1996-01-23

An active, phase-coded, time-grating transponder and a synthetic-aperture radar (SAR) and signal processor means, in combination, allow the recognition and location of the transponder (tag) in the SAR image and allow communication of information messages from the transponder to the SAR. The SAR is an illuminating radar having special processing modifications in an image-formation processor to receive an echo from a remote transponder, after the transponder receives and retransmits the SAR illuminations, and to enhance the transponder`s echo relative to surrounding ground clutter by recognizing special transponder modulations from phase-shifted from the transponder retransmissions. The remote radio-frequency tag also transmits information to the SAR through a single antenna that also serves to receive the SAR illuminations. Unique tag-modulation and SAR signal processing techniques, in combination, allow the detection and precise geographical location of the tag through the reduction of interfering signals from ground clutter, and allow communication of environmental and status information from said tag to be communicated to said SAR. 4 figs.

Development of chemical inhibitors of the SARS coronavirus: viral helicase as a potential target.

PubMed

Keum, Young-Sam; Jeong, Yong-Joo

2012-11-15

Severe acute respiratory syndrome (SARS) was the first pandemic in the 21st century to claim more than 700 lives worldwide. However, effective anti-SARS vaccines or medications are currently unavailable despite being desperately needed to adequately prepare for a possible SARS outbreak. SARS is caused by a novel coronavirus, and one of its components, a viral helicase, is emerging as a promising target for the development of chemical SARS inhibitors. In the following review, we describe the characterization, family classification, and kinetic movement mechanisms of the SARS coronavirus (SCV) helicase-nsP13. We also discuss the recent progress in the identification of novel chemical inhibitors of nsP13 in the context of our recent discovery of the strong inhibition of the SARS helicase by natural flavonoids, myricetin and scutellarein. These compounds will serve as important resources for the future development of anti-SARS medications. Copyright © 2012 Elsevier Inc. All rights reserved.

Cross-calibration between airborne SAR sensors

NASA Technical Reports Server (NTRS)

Zink, Manfred; Olivier, Philippe; Freeman, Anthony

1993-01-01

As Synthetic Aperture Radar (SAR) system performance and experience in SAR signature evaluation increase, quantitative analysis becomes more and more important. Such analyses require an absolute radiometric calibration of the complete SAR system. To keep the expenditure on calibration of future multichannel and multisensor remote sensing systems (e.g., X-SAR/SIR-C) within a tolerable level, data from different tracks and different sensors (channels) must be cross calibrated. The 1989 joint E-SAR/DC-8 SAR calibration campaign gave a first opportunity for such an experiment, including cross sensor and cross track calibration. A basic requirement for successful cross calibration is the stability of the SAR systems. The calibration parameters derived from different tracks and the polarimetric properties of the uncalibrated data are used to describe this stability. Quality criteria for a successful cross calibration are the agreement of alpha degree values and the consistency of radar cross sections of equally sized corner reflectors. Channel imbalance and cross talk provide additional quality in case of the polarimetric DC-8 SAR.

Mapping palm oil expansion using SAR to study the impact on the CO2 cycle

NASA Astrophysics Data System (ADS)

Pohl, Christine

2014-06-01

With Malaysia being the second largest palm oil producer in the world and the fact that palm oil ranks first in vegetable oil production on the world market the palm oil industry became an important factor in the country. Along with the expansion of palm oil across the nation causing deforestation of natural rain forest and conversion of peat land into plantation land there are several factors causing a tremendous increase in carbon dioxide (CO2) emissions. Main causes of CO2 emission apart from deforestation and peat-land conversion are the fires to create plantation land plus the fires burning waste products of the plantations itself. This paper describes a project that aims at the development of a remote sensing monitoring system to allow a continuous observation of oil palm plantation activities and expansion in order to be able to quantify CO2 emissions. The research concentrates on developing a spaceborne synthetic aperture radar information extraction system for palm oil plantations in the Tropics. This will lead to objective figures that can be used internationally to create a policy implementation plan to sustainably reduce CO2 emission in the future.

Productivity of Spring Chinook Salmon and Summer Steelhead in the John Day River Basin, 2008 Annual Technical Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wilson, Wayne H.; Schricker, Jaym'e; Ruzychi, James R.

The John Day River subbasin supports one of the last remaining intact wild populations of spring Chinook salmon and summer steelhead in the Columbia River Basin. These populations remain depressed relative to historic levels and limited information is available for steelhead life history. Numerous habitat protection and rehabilitation projects have been implemented in the basin to improve salmonid freshwater production and survival. However, these projects often lack effectiveness monitoring. While our monitoring efforts outlined here will not specifically measure the effectiveness of any particular project, they will provide much needed programmatic or watershed (status and trend) information to help evaluatemore » project-specific effectiveness monitoring efforts as well as meet some data needs as index stocks. Our continued monitoring efforts to estimate salmonid smolt abundance, age structure, SAR, smolts/redd, freshwater habitat use, and distribution of critical life states will enable managers to assess the long-term effectiveness of habitat projects and to differentiate freshwater and ocean survival. Because Columbia Basin managers have identified the John Day subbasin spring Chinook population as an index population for assessing the effects of alternative future management actions on salmon stocks in the Columbia Basin (Schaller et al. 1999) we continue our ongoing studies. This project is high priority based on the level of emphasis by the NWPPC Fish and Wildlife Program, Independent Scientific Advisory Board (ISAB), Independent Scientific Review Panel (ISRP), NOAA National Marine Fisheries Service (NMFS), and the Oregon Plan for Salmon and Watersheds (OWEB). Each of these groups have placed priority on monitoring and evaluation to provide the real-time data to guide restoration and adaptive management in the region. The objective is to estimate smolt-to-adult survival rates (SAR) and out-migrant abundance for spring Chinook Oncorhynchus tshawytscha and summer steelhead O. mykiss and life history characteristics of summer steelhead.« less

A comparison of photograph-interpreted and IfSAR-derived maps of polar bear denning habitat for the 1002 Area of the Arctic National Wildlife Refuge, Alaska

USGS Publications Warehouse

Durner, George M.; Atwood, Todd C.

2018-05-11

Polar bears (Ursus maritimus) in Alaska use the Arctic National Wildlife Refuge (ANWR) for maternal denning. Pregnant bears den in snow banks for more than 3 months in winter during which they give birth to and nurture young. Denning is one of the most vulnerable times in polar bear life history as the family group cannot simply walk away from a disturbance without jeopardizing survival of newly born cubs. The ANWR includes the “1002 Area”, a region recently opened for oil and gas exploration by the U.S. Department of the Interior (DOI). As a part of its mission, the DOI “… protects and manages the Nation's natural resources …” and is therefore responsible for conserving polar bears and encouraging development of energy potential. Because future industrial activities could overlap habitats used by denning polar bears, identifying these habitats can inform the decisions of resource managers tasked to develop resources and protect polar bears. To help inform these efforts, we qualitatively compared the distribution of denning habitat identified by two different methods: previously published habitat from manual interpretation of aerial photographs, and habitat derived by computer interrogation of interferometric synthetic aperture radar (IfSAR) digital terrain models (DTM). Because photograph-interpreted methods depicted denning habitat as a line and IfSAR-derived methods depicted habitat as a polygon, we assessed agreement between the two methods with distance measurements. We found that 77.5 percent of IfSAR-derived denning habitat (79.6 km2 ; 1.2 percent of the 6,837.0 km2 1002 Area) was within 600 m of photograph-interpreted habitat (3,026.9 km), including 53.9 percent within 200 m. This distribution differed from that of randomly distributed points, as only 49.4 percent of these occurred within 600 m of photograph-interpreted habitat, including 18.3 percent within 200 m. Both methods appear to identify the major physiographic features that polar bears might select for denning. IfSAR-derived methods identified habitat at greater frequency beyond major landscape features such as coastal bluffs, river banks and lakeshores, were more likely to identify isolated pockets of putative denning habitat, and were easier to implement than deriving habitat from photograph-interpretive efforts. However, previous research suggests that photograph-interpretation methods may identify denning habitat more correctly than computer interrogation of IfSAR DTMs. Future work should quantify the distribution of IfSAR-derived denning habitat relative to actual landscape features and polar bear maternal dens in the 1002 Area, and investigate the feasibility of habitat identification from finer grained DTMs.

Context-sensitive design and human interaction principles for usable, useful, and adoptable radars

NASA Astrophysics Data System (ADS)

McNamara, Laura A.; Klein, Laura M.

2016-05-01

The evolution of exquisitely sensitive Synthetic Aperture Radar (SAR) systems is positioning this technology for use in time-critical environments, such as search-and-rescue missions and improvised explosive device (IED) detection. SAR systems should be playing a keystone role in the United States' Intelligence, Surveillance, and Reconnaissance activities. Yet many in the SAR community see missed opportunities for incorporating SAR into existing remote sensing data collection and analysis challenges. Drawing on several years' of field research with SAR engineering and operational teams, this paper examines the human and organizational factors that mitigate against the adoption and use of SAR for tactical ISR and operational support. We suggest that SAR has a design problem, and that context-sensitive, human and organizational design frameworks are required if the community is to realize SAR's tactical potential.

Further SEASAT SAR coastal ocean wave analysis

NASA Technical Reports Server (NTRS)

Kasischke, E. S.; Shuchman, R. A.; Meadows, G. A.; Jackson, P. L.; Tseng, Y.

1981-01-01

Analysis techniques used to exploit SEASAT synthetic aperture radar (SAR) data of gravity waves are discussed and the SEASAT SAR's ability to monitor large scale variations in gravity wave fields in both deep and shallow water is evaluated. The SAR analysis techniques investigated included motion compensation adjustments and the semicausal model for spectral analysis of SAR wave data. It was determined that spectra generated from fast Fourier transform analysis (FFT) of SAR wave data were not significantly altered when either range telerotation adjustments or azimuth focus shifts were used during processing of the SAR signal histories, indicating that SEASAT imagery of gravity waves is not significantly improved or degraded by motion compensation adjustments. Evaluation of the semicausal (SC) model using SEASAT SAR data from Rev. 974 indicates that the SC spectral estimates were not significantly better than the FFT results.

Subsidence monitoring network: an Italian example aimed at a sustainable hydrocarbon E&P activity

NASA Astrophysics Data System (ADS)

Dacome, M. C.; Miandro, R.; Vettorel, M.; Roncari, G.

2015-11-01

According to the Italian law in order to start-up any new hydrocarbon exploitation activity, an Environmental Impact Assessment study has to be presented, including a monitoring plan, addressed to foresee, measure and analyze in real time any possible impact of the project on the coastal areas and on those ones in the close inland located. The occurrence of subsidence, that could partly be related to hydrocarbon production, both on-shore and off-shore, can generate great concern in those areas where its occurrence may have impacts on the local environment. ENI, following the international scientific community recommendations on the matter, since the beginning of 90's years, implemented a cutting-edge monitoring network, with the aim to prevent, mitigate and control geodynamics phenomena generated in the activity areas, with a particular attention to conservation and protection of environmental and territorial equilibrium, taking care of what is known as "sustainable development". The current ENI implemented monitoring surveys can be divided as: - Shallow monitoring: spirit levelling surveys, continuous GPS surveys in permanent stations, SAR surveys, assestimeter subsurface compaction monitoring, ground water level monitoring, LiDAR surveys, bathymetrical surveys. - Deep monitoring: reservoir deep compaction trough radioactive markers, reservoir static (bottom hole) pressure monitoring. All the information, gathered through the monitoring network, allow: 1. to verify if the produced subsidence is evolving accordingly with the simulated forecast. 2. to provide data to revise and adjust the prediction compaction models 3. to put in place the remedial actions if the impact exceeds the threshold magnitude originally agreed among the involved parties. ENI monitoring plan to measure and monitor the subsidence process, during field production and also after the field closure, is therefore intended to support a sustainable field development and an acceptable exploitation programme in which the actual risk connected with the field production is evaluated in advance, shared and agreed among all the involved subjects: oil company, stakeholders and local community (with interests in the affected area).

The Membrane Dynamics of Pexophagy Are Influenced by Sar1p in Pichia pastoris

PubMed Central

Schroder, Laura A.; Ortiz, Michael V.

2008-01-01

Several Sec proteins including a guanosine diphosphate/guanosine triphosphate exchange factor for Sar1p have been implicated in autophagy. In this study, we investigated the role of Sar1p in pexophagy by expressing dominant-negative mutant forms of Sar1p in Pichia pastoris. When expressing sar1pT34N or sar1pH79G, starvation-induced autophagy, glucose-induced micropexophagy, and ethanol-induced macropexophagy are dramatically suppressed. These Sar1p mutants did not affect the initiation or expansion of the sequestering membranes nor the trafficking of Atg11p and Atg9p to these membranes during micropexophagy. However, the lipidation of Atg8p and assembly of the micropexophagic membrane apparatus, which are essential to complete the incorporation of the peroxisomes into the degradative vacuole, were inhibited when either Sar1p mutant protein was expressed. During macropexophagy, the expression of sar1pT34N inhibited the formation of the pexophagosome, whereas sar1pH79G suppressed the delivery of the peroxisome from the pexophagosome to the vacuole. The pexophagosome contained Atg8p in wild-type cells, but in cells expressing sar1pH79G these organelles contain both Atg8p and endoplasmic reticulum components as visualized by DsRFP-HDEL. Our results demonstrate key roles for Sar1p in both micro- and macropexophagy. PMID:18768759

Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

NASA Astrophysics Data System (ADS)

Zhu, Wu; Ding, Xiao-Li; Jung, Hyung-Sup; Zhang, Qin; Zhang, Bo-Chen; Qu, Wei

2016-08-01

Synthetic Aperture Radar Interferometry (InSAR) has demonstrated its potential for high-density spatial mapping of ground displacement associated with earthquakes, volcanoes, and other geologic processes. However, this technique may be affected by the ionosphere, which can result in the distortions of Synthetic Aperture Radar (SAR) images, phases, and polarization. Moreover, ionospheric effect has become and is becoming further significant with the increasing interest in low-frequency SAR systems, limiting the further development of InSAR technique. Although some research has been carried out, thorough analysis of ionospheric influence on true SAR imagery is still limited. Based on this background, this study performs a thorough investigation of ionospheric effect on InSAR through processing L-band ALOS-1/PALSAR-1 images and dual-frequency Global Positioning System (GPS) data over Hong Kong, where the phenomenon of ionospheric irregularities often occurs. The result shows that the small-scale ionospheric irregularities can cause the azimuth pixel shifts and phase advance errors on interferograms. Meanwhile, it is found that these two effects result in the stripe-shaped features in InSAR images. The direction of the stripe-shaped effects keep approximately constant in space for our InSAR dataset. Moreover, the GPS-derived rate of total electron content change index (ROTI), an index to reflect the level of ionospheric disturbances, may be a useful indicator for predicting the ionospheric effect for SAR images. This finding can help us evaluate the quality of SAR images when considering the ionospheric effect.

Surface vimentin is critical for the cell entry of SARS-CoV.

PubMed

Yu, Yvonne Ting-Chun; Chien, Ssu-Chia; Chen, I-Yin; Lai, Chia-Tsen; Tsay, Yeou-Guang; Chang, Shin C; Chang, Ming-Fu

2016-01-22

Severe acute respiratory syndrome coronavirus (SARS-CoV) caused a global panic due to its high morbidity and mortality during 2002 and 2003. Soon after the deadly disease outbreak, the angiotensin-converting enzyme 2 (ACE2) was identified as a functional cellular receptor in vitro and in vivo for SARS-CoV spike protein. However, ACE2 solely is not sufficient to allow host cells to become susceptible to SARS-CoV infection, and other host factors may be involved in SARS-CoV spike protein-ACE2 complex. A host intracellular filamentous cytoskeletal protein vimentin was identified by immunoprecipitation and LC-MS/MS analysis following chemical cross-linking on Vero E6 cells that were pre-incubated with the SARS-CoV spike protein. Moreover, flow cytometry data demonstrated an increase of the cell surface vimentin level by 16.5 % after SARS-CoV permissive Vero E6 cells were treated with SARS-CoV virus-like particles (VLPs). A direct interaction between SARS-CoV spike protein and host surface vimentin was further confirmed by far-Western blotting. In addition, antibody neutralization assay and shRNA knockdown experiments indicated a vital role of vimentin in cell binding and uptake of SARS-CoV VLPs and the viral spike protein. A direct interaction between vimentin and SARS-CoV spike protein during viral entry was observed. Vimentin is a putative anti-viral drug target for preventing/reducing the susceptibility to SARS-CoV infection.

An improved synthesis and biological evaluation of a new cage-like bifunctional chelator, 4-((8-amino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane-1-ylamino)methyl)benzoic acid, for 64Cu radiopharmaceuticals.

PubMed

Cai, Hancheng; Li, Zibo; Huang, Chiun-Wei; Park, Ryan; Shahinian, Anthony H; Conti, Peter S

2010-01-01

Stable attachment of (64)Cu(2+) to a targeting molecule usually requires the use of a bifunctional chelator (BFC). Sarcophagine (Sar) ligands rapidly coordinate (64)Cu(2+) within the multiple macrocyclic rings comprising the cage structure under mild conditions, providing high stability in vivo. Previously, we have designed a new versatile cage-like BFC Sar ligand, 4-((8-amino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]icosane-1-ylamino)methyl)benzoic acid (AmBaSar), for (64)Cu radiopharmaceuticals. Here we report the improved synthesis of AmBaSar, (64)Cu(2+) labeling conditions and its biological evaluation compared with the known BFC 1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA). The AmBaSar was synthesized in four steps starting from (1,8-diamine-Sar) cobalt(III) pentachloride ([Co(DiAmSar)]Cl(5)) using an improved synthetic method. The AmBaSar was labeled with (64)Cu(2+) in pH 5.0 ammonium acetate buffer solution at room temperature, followed by analysis and purification with HPLC. The in vitro stability of (64)Cu-AmBaSar complex was evaluated in phosphate buffered saline (PBS), fetal bovine serum and mouse blood. The microPET imaging and biodistribution studies of (64)Cu-AmBaSar were performed in Balb/c mice, and the results were compared with (64)Cu-DOTA. The AmBaSar was readily prepared and characterized by MS and (1)H NMR. The radiochemical yield of (64)Cu-AmBaSar was >or=98% after 30 min of incubation at 25 degrees C. The (64)Cu-AmBaSar complex was analyzed and purified by HPLC with a retention time of 17.9 min. The radiochemical purity of (64)Cu-AmBaSar was more than 97% after 26 h of incubation in PBS or serum. The biological evaluation of (64)Cu-AmBaSar in normal mouse demonstrated renal clearance as the primary mode of excretion, with improved stability in vivo compared to (64)Cu-DOTA. The new cage-like BFC AmBaSar was prepared using a simplified synthetic method. The (64)Cu-AmBaSar complex could be obtained rapidly with high radiochemical yield (>/=98%) under mild conditions. In vitro and in vivo evaluation of AmBaSar demonstrated its promising potential for preparation of (64)Cu radiopharmaceuticals. Copyright 2010. Published by Elsevier Inc.

Polarimetric SAR image classification based on discriminative dictionary learning model

NASA Astrophysics Data System (ADS)

Sang, Cheng Wei; Sun, Hong

2018-03-01

Polarimetric SAR (PolSAR) image classification is one of the important applications of PolSAR remote sensing. It is a difficult high-dimension nonlinear mapping problem, the sparse representations based on learning overcomplete dictionary have shown great potential to solve such problem. The overcomplete dictionary plays an important role in PolSAR image classification, however for PolSAR image complex scenes, features shared by different classes will weaken the discrimination of learned dictionary, so as to degrade classification performance. In this paper, we propose a novel overcomplete dictionary learning model to enhance the discrimination of dictionary. The learned overcomplete dictionary by the proposed model is more discriminative and very suitable for PolSAR classification.

SAR image registration based on Susan algorithm

NASA Astrophysics Data System (ADS)

Wang, Chun-bo; Fu, Shao-hua; Wei, Zhong-yi

2011-10-01

Synthetic Aperture Radar (SAR) is an active remote sensing system which can be installed on aircraft, satellite and other carriers with the advantages of all day and night and all-weather ability. It is the important problem that how to deal with SAR and extract information reasonably and efficiently. Particularly SAR image geometric correction is the bottleneck to impede the application of SAR. In this paper we introduces image registration and the Susan algorithm knowledge firstly, then introduces the process of SAR image registration based on Susan algorithm and finally presents experimental results of SAR image registration. The Experiment shows that this method is effective and applicable, no matter from calculating the time or from the calculation accuracy.

School children from Punta Arenas, Chile, talk with Dr. David Imel, an AirSAR scientist from NASA JPL, during AirSAR 2004

NASA Image and Video Library

2004-03-10

School children from Punta Arenas, Chile, talk with Dr. David Imel, an AirSAR scientist from NASA JPL, during AirSAR 2004. AirSAR 2004 is a three-week expedition by an international team of scientists that uses an all-weather imaging tool, called the Airborne Synthetic Aperture Radar (AirSAR) which is located onboard NASA's DC-8 airborne laboratory. Scientists from many parts of the world including NASA's Jet Propulsion Laboratory are combining ground research done in several areas in Central and South America with NASA's AirSAR technology to improve and expand on the quality of research they are able to conduct. In South America and Antarctica, AirSAR collected imagery and data to help determine the contribution of Southern Hemisphere glaciers to sea level rise due to climate change. In Patagonia, researchers found this contribution had more than doubled from 1995 to 2000, compared to the previous 25 years. AirSAR data will make it possible to determine whether that trend is continuing or accelerating. AirSAR will also provide reliable information on ice shelf thickness to measure the contribution of the glaciers to sea level.

Maximum a posteriori classification of multifrequency, multilook, synthetic aperture radar intensity data

NASA Technical Reports Server (NTRS)

Rignot, E.; Chellappa, R.

1993-01-01

We present a maximum a posteriori (MAP) classifier for classifying multifrequency, multilook, single polarization SAR intensity data into regions or ensembles of pixels of homogeneous and similar radar backscatter characteristics. A model for the prior joint distribution of the multifrequency SAR intensity data is combined with a Markov random field for representing the interactions between region labels to obtain an expression for the posterior distribution of the region labels given the multifrequency SAR observations. The maximization of the posterior distribution yields Bayes's optimum region labeling or classification of the SAR data or its MAP estimate. The performance of the MAP classifier is evaluated by using computer-simulated multilook SAR intensity data as a function of the parameters in the classification process. Multilook SAR intensity data are shown to yield higher classification accuracies than one-look SAR complex amplitude data. The MAP classifier is extended to the case in which the radar backscatter from the remotely sensed surface varies within the SAR image because of incidence angle effects. The results obtained illustrate the practicality of the method for combining SAR intensity observations acquired at two different frequencies and for improving classification accuracy of SAR data.

Receptor-binding domain as a target for developing SARS vaccines.

PubMed

Zhu, Xiaojie; Liu, Qi; Du, Lanying; Lu, Lu; Jiang, Shibo

2013-08-01

A decade ago, severe acute respiratory syndrome (SARS) coronavirus (SARS-CoV) caused a global pandemic with a mortality rate of 10%. Reports of recent outbreaks of a SARS-like disease caused by Middle East respiratory syndrome coronavirus (MERS-CoV) have raised serious concerns of a possible reemergence of SARS-CoV, either by laboratory escape or the presence of a natural reservoir. Therefore, the development of effective and safe SARS vaccines is still needed. Based on our previous studies, we believe that the receptor-binding domain (RBD) in the S1 subunit of the SARS-CoV spike (S) protein is the most important target for developing a SARS vaccine. In particular, RBD of S protein contains the critical neutralizing domain (CND), which is able to induce highly potent neutralizing antibody response and cross-protection against divergent SARS-CoV strains. Furthermore, a RBD-based subunit vaccine is expected to be safer than other vaccines that may induce Th2-type immunopathology. This review will discuss key advances in the development of RBD-based SARS vaccines and the possibility of using a similar strategy to develop vaccines against MERS-CoV.

Crustal Deformation at the Arabian Plate-Boundary observed by InSAR

NASA Astrophysics Data System (ADS)

Jonsson, S.; Cavalié, O.; Akoglu, A. M.; Wang, T.; Xu, W.; Feng, G.; Dutta, R.; Abdullin, A. K.

2013-12-01

The Arabian plate is bounded by a variety of active plate boundaries, with extension in the Red Sea and Gulf of Aden to the south, compression in Turkey and Iran to the north, and transform faults to the west and to the east. Internally, however, the Arabian plate has been shown to be tectonically rather stable, despite evidence of recent volcanism and earthquake faulting. We use InSAR observations to study recent tectonic and volcanic activity at several locations at the Arabian plate boundary as well within the plate itself. The region near the triple junction between the Arabian, Eurasian, and Anatolian plates has often been the focus of studies on continental deformation behavior and interseismic deformation. Here we use large-scale InSAR data processing to map the deformation near the triple junction and find the deformation to be focused on major faults with little intra-plate deformation. The eastern part of the East Anatolian Fault appears to have a very shallow locking depth with limited fault-normal deformation. Several major earthquakes that have occurred in recent years on the Arabian plate boundary, including the 2011 magnitude 7.1 Van earthquake in eastern Turkey. It occurred as a result of convergence of the Arabian plate towards Eurasia and caused significant surface deformation that we have analyzed with multiple coseismic InSAR, GPS, and coastal uplift observations. We use high-resolution Cosmo-Skymed and TerraSAR-X data to derive 3D coseismic displacements from offsets alone, as some of the interferograms are almost completely incoherent. By identifying point-like targets within the images, we were able to derive accurate pixel offsets between SAR sub-images containing such targets, which we used to estimate the 3D coseismic displacements. The derived 3D displacement field helped in constraining the causative northward dipping thrust-fault. The Qadimah fault is a recently discovered fault located on the Red Sea coast north of Jeddah and under the King Abdullah Economic City, a planned $50 billion harbor city. The fault is a normal fault, parallel to the Red Sea, but it is unclear if the fault is still active and poses significant hazard to the new city. We use MERIS-corrected Envisat InSAR data to study the limited interseismic deformation across the fault and the results suggest that more investigations will be needed to assess the activity of the fault. Several volcanic events have taken place in the region during the past several years, including the 2007-8 Jebel at Tair island (Red Sea) eruption, the 2009 Harrat Lunayyir (western Saudi Arabia) magmatic intrusion, and the 2011-12 Zubair islands (Red Sea) eruption. All these three volcanic events were fed by dike intrusions whose geometry we constrain using the InSAR and optical data. The derived dike orientations provide information about extensional stress field in and around the Red Sea, although on Tair island the upper-most part of the feeder dike was controlled by local stresses within the volcanic edifice.

Evidence that TMPRSS2 Activates the Severe Acute Respiratory Syndrome Coronavirus Spike Protein for Membrane Fusion and Reduces Viral Control by the Humoral Immune Response▿

PubMed Central

Glowacka, Ilona; Bertram, Stephanie; Müller, Marcel A.; Allen, Paul; Soilleux, Elizabeth; Pfefferle, Susanne; Steffen, Imke; Tsegaye, Theodros Solomon; He, Yuxian; Gnirss, Kerstin; Niemeyer, Daniela; Schneider, Heike; Drosten, Christian; Pöhlmann, Stefan

2011-01-01

The spike (S) protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) can be proteolytically activated by cathepsins B and L upon viral uptake into target cell endosomes. In contrast, it is largely unknown whether host cell proteases located in the secretory pathway of infected cells and/or on the surface of target cells can cleave SARS S. We along with others could previously show that the type II transmembrane protease TMPRSS2 activates the influenza virus hemagglutinin and the human metapneumovirus F protein by cleavage. Here, we assessed whether SARS S is proteolytically processed by TMPRSS2. Western blot analysis revealed that SARS S was cleaved into several fragments upon coexpression of TMPRSS2 (cis-cleavage) and upon contact between SARS S-expressing cells and TMPRSS2-positive cells (trans-cleavage). cis-cleavage resulted in release of SARS S fragments into the cellular supernatant and in inhibition of antibody-mediated neutralization, most likely because SARS S fragments function as antibody decoys. trans-cleavage activated SARS S on effector cells for fusion with target cells and allowed efficient SARS S-driven viral entry into targets treated with a lysosomotropic agent or a cathepsin inhibitor. Finally, ACE2, the cellular receptor for SARS-CoV, and TMPRSS2 were found to be coexpressed by type II pneumocytes, which represent important viral target cells, suggesting that SARS S is cleaved by TMPRSS2 in the lung of SARS-CoV-infected individuals. In summary, we show that TMPRSS2 might promote viral spread and pathogenesis by diminishing viral recognition by neutralizing antibodies and by activating SARS S for cell-cell and virus-cell fusion. PMID:21325420

Synthetic aperture radar image formation for the moving-target and near-field bistatic cases

NASA Astrophysics Data System (ADS)

Ding, Yu

This dissertation addresses topics in two areas of synthetic aperture radar (SAR) image formation: time-frequency based SAR imaging of moving targets and a fast backprojection (BP) algorithm for near-field bistatic SAR imaging. SAR imaging of a moving target is a challenging task due to unknown motion of the target. We approach this problem in a theoretical way, by analyzing the Wigner-Ville distribution (WVD) based SAR imaging technique. We derive approximate closed-form expressions for the point-target response of the SAR imaging system, which quantify the image resolution, and show how the blurring in conventional SAR imaging can be eliminated, while the target shift still remains. Our analyses lead to accurate prediction of the target position in the reconstructed images. The derived expressions also enable us to further study additional aspects of WVD-based SAR imaging. Bistatic SAR imaging is more involved than the monostatic SAR case, because of the separation of the transmitter and the receiver, and possibly the changing bistatic geometry. For near-field bistatic SAR imaging, we develop a novel fast BP algorithm, motivated by a newly proposed fast BP algorithm in computer tomography. First we show that the BP algorithm is the spatial-domain counterpart of the benchmark o -- k algorithm in bistatic SAR imaging, yet it avoids the frequency-domain interpolation in the o -- k algorithm, which may cause artifacts in the reconstructed image. We then derive the band-limited property for BP methods in both monostatic and bistatic SAR imaging, which is the basis for developing the fast BP algorithm. We compare our algorithm with other frequency-domain based algorithms, and show that it achieves better reconstructed image quality, while having the same computational complexity as that of the frequency-domain based algorithms.

A study on SARS awareness and health-seeking behaviour - findings from a sampled population attending National Healthcare Group Polyclinics.

PubMed

Seng, S L; Lim, P S; Ng, M Y; Wong, H B; Emmanuel, S C

2004-09-01

The study aimed to assess the effectiveness of massive SARS public education effort on SARS awareness and the conduct of those suspected of having SARS. Five hundred and ninety-three respondents attending the National Healthcare Group Polyclinics (NHGP) participated in the survey from 9 to 13 June 2003. Associations between awareness of SARS symptoms and (i) first action to be taken and (ii) mode of transportation used, if the respondent was suspected of having SARS, were analysed using Chi-square or Fisher's exact tests. Logistic regression was performed to adjust for relevant covariates. The majority (92.7%) of the respondents were aware of SARS symptoms. Television (91.6%), newspaper (65.2%) and radio (30.4%) formed the top 3 sources of information on SARS. Slightly more than half (51.6%) of those who suspect themselves of having SARS would choose to visit their primary health care doctors, while 22.7% of the respondents would go to Tan Tock Seng Hospital (TTSH). If they suspected themselves to have SARS, most (84.9%) of the 578 respondents would react appropriately by taking the SARS ambulance or driving themselves to TTSH. However, 60 respondents would nonetheless take public transport to TTSH [by taxi 8.5%, mass rapid transit (MRT) or bus 1.9%]. In particular, the retired with lower educational levels were likely to be oblivious both to the symptoms of SARS and the possible consequences of travelling by inappropriate transport. Despite more than 2 months of intensive SARS public education in Singapore, there remain important gaps in knowledge and appropriate behaviour that have to be bridged.

Near real time inverse source modeling and stress filed assessment: the requirement of a volcano fast response system

NASA Astrophysics Data System (ADS)

Shirzaei, Manoochehr; Walter, Thomas

2010-05-01

Volcanic unrest and eruptions are one of the major natural hazards next to earthquakes, floods, and storms. It has been shown that many of volcanic and tectonic unrests are triggered by changes in the stress field induced by nearby seismic and magmatic activities. In this study, as part of a mobile volcano fast response system so-called "Exupery" (www.exupery-vfrs.de) we present an arrangement for semi real time assessing the stress field excited by volcanic activity. This system includes; (1) an approach called "WabInSAR" dedicated for advanced processing of the satellite data and providing an accurate time series of the surface deformation [1, 2], (2) a time dependent inverse source modeling method to investigate the source of volcanic unrest using observed surface deformation data [3, 4], (3) the assessment of the changes in stress field induced by magmatic activity at the nearby volcanic and tectonic systems. This system is implemented in a recursive manner that allows handling large 3D data sets in an efficient and robust way which is requirement of an early warning system. We have applied and validated this arrangement on Mauna Loa volcano, Hawaii Island, to assess the influence of the time dependent activities of Mauna Loa on earthquake occurrence at the Kaoiki seismic zone. References [1] M. Shirzaei and T. R. Walter, "Wavelet based InSAR (WabInSAR): a new advanced time series approach for accurate spatiotemporal surface deformation monitoring," IEEE, pp. submitted, 2010. [2] M. Shirzaei and R. T. Walter, "Deformation interplay at Hawaii Island through InSAR time series and modeling," J. Geophys Res., vol. submited, 2009. [3] M. Shirzaei and T. R. Walter, "Randomly Iterated Search and Statistical Competency (RISC) as powerful inversion tools for deformation source modeling: application to volcano InSAR data," J. Geophys. Res., vol. 114, B10401, doi:10.1029/2008JB006071, 2009. [4] M. Shirzaei and T. R. Walter, "Genetic algorithm combined with Kalman filter as powerful tool for nonlinear time dependent inverse modelling: Application to volcanic deformation time series," J. Geophys. Res., pp. submitted, 2010.

Leads Detection Using Mixture Statistical Distribution Based CRF Algorithm from Sentinel-1 Dual Polarization SAR Imagery

NASA Astrophysics Data System (ADS)

Zhang, Yu; Li, Fei; Zhang, Shengkai; Zhu, Tingting

2017-04-01

Synthetic Aperture Radar (SAR) is significantly important for polar remote sensing since it can provide continuous observations in all days and all weather. SAR can be used for extracting the surface roughness information characterized by the variance of dielectric properties and different polarization channels, which make it possible to observe different ice types and surface structure for deformation analysis. In November, 2016, Chinese National Antarctic Research Expedition (CHINARE) 33rd cruise has set sails in sea ice zone in Antarctic. Accurate leads spatial distribution in sea ice zone for routine planning of ship navigation is essential. In this study, the semantic relationship between leads and sea ice categories has been described by the Conditional Random Fields (CRF) model, and leads characteristics have been modeled by statistical distributions in SAR imagery. In the proposed algorithm, a mixture statistical distribution based CRF is developed by considering the contexture information and the statistical characteristics of sea ice for improving leads detection in Sentinel-1A dual polarization SAR imagery. The unary potential and pairwise potential in CRF model is constructed by integrating the posteriori probability estimated from statistical distributions. For mixture statistical distribution parameter estimation, Method of Logarithmic Cumulants (MoLC) is exploited for single statistical distribution parameters estimation. The iteration based Expectation Maximal (EM) algorithm is investigated to calculate the parameters in mixture statistical distribution based CRF model. In the posteriori probability inference, graph-cut energy minimization method is adopted in the initial leads detection. The post-processing procedures including aspect ratio constrain and spatial smoothing approaches are utilized to improve the visual result. The proposed method is validated on Sentinel-1A SAR C-band Extra Wide Swath (EW) Ground Range Detected (GRD) imagery with a pixel spacing of 40 meters near Prydz Bay area, East Antarctica. Main work is listed as follows: 1) A mixture statistical distribution based CRF algorithm has been developed for leads detection from Sentinel-1A dual polarization images. 2) The assessment of the proposed mixture statistical distribution based CRF method and single distribution based CRF algorithm has been presented. 3) The preferable parameters sets including statistical distributions, the aspect ratio threshold and spatial smoothing window size have been provided. In the future, the proposed algorithm will be developed for the operational Sentinel series data sets processing due to its less time consuming cost and high accuracy in leads detection.