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Sample records for ceriodaphnia cornuta sars

  1. Population dynamics of Moina minuta Hansen (1899, Ceriodaphnia cornuta Sars (1886, and Diaphanosoma spinulosum Herbst (1967 (Crustacea: Branchiopoda in different nutrients (N and P concentration ranges Dinâmica populacional de Moina minuta Hansen (1899, Ceriodaphnia cornuta Sars (1886 e Diaphanosoma spinulosum Herbst (1967 (Crustacea: Branchiopoda em diferentes faixas de concentração de nutrientes (N e P

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    Ana Carolina Brito Vieira

    2011-03-01

    Full Text Available AIM: Aquatic environments of semi-arid regions are subject to changes in water quality and volume due to short and irregular rain seasons. Consequently, zooplankton composition changes in association to fluctuations in the trophic degree. To comprehend these processes, this study analyzed the influence of nutrient concentrations (N and P on the population dynamics of three species of Cladocera - Moina minuta, Ceriodaphnia cornuta, and Diapahnosoma spinulosum - from the Taperoá II Dam, Paraíba, Brazil; METHODS: Animals were experimentally submitted to different nutrient concentrations as a means to reproduce specific trophic conditions from natural environments. Zooplankton densities were evaluated once every three days, with food (i.e. algal cultures being supplied in alternate days. To compare population growth, an ANOVA was performed, followed by Tukey's HSD post-hoc test; RESULTS: The population growth of the three species differed significantly both among species and among treatments. Moina minuta populations showed higher growth rates under higher nutrient concentrations, whereas Ceriodaphnia cornuta growed more efficiently in intermediate concentrations, and Diaphanosoma spinulosum showed a better development in low nutrient concentrations; CONCLUSIONS: The results from the experimental approach, presented here, are similar to what is observed in the field, based on previous studies carried out in the Taperoá II Dam. Therefore, these results suggest that the hydrological cycle seems to be the major determinant of zooplankton population dynamics in aquatic semi-arid environmentsOBJETIVO: Os ambientes aquáticos de regiões semi-áridas sofrem alterações na qualidade da água e no seu volume devido à irregularidade do período chuvoso. Consequentemente, o zooplâncton sofre alterações em sua composição com a evolução do estado trófico. Para a compreensão desse processo, este trabalho analisou experimentalmente a influência da

  2. Toxicidad aguda y crónica del lindano sobre Ceriodaphnia cornuta (Cladocera: Daphniidae)

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    Jorgelina Juárez; Alcira Villagra de Gamundi

    2011-01-01

    El lindano es un plaguicida organoclorado cuya toxicidad produce efectos nocivos en la salud humana y la biota. El objetivo de este estudio fue evaluar la toxicidad aguda y crónica del lindano sobre el microcrustáceo Ceriodaphnia cornuta. Para las pruebas agudas se empleó un diseño estático, usando 10 neonatos ≤ 24 horas de edad para el control y para cada concentración de lindano (5, 10, 15, 20 y 25 mg/L). Se realizaron tres réplicas de cada tratamiento. Se controló la inmovilización de los ...

  3. Toxicidad aguda y crónica del lindano sobre Ceriodaphnia cornuta (Cladocera: Daphniidae

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    Jorgelina Juárez

    2011-05-01

    Full Text Available El lindano es un plaguicida organoclorado cuya toxicidad produce efectos nocivos en la salud humana y la biota. El objetivo de este estudio fue evaluar la toxicidad aguda y crónica del lindano sobre el microcrustáceo Ceriodaphnia cornuta. Para las pruebas agudas se empleó un diseño estático, usando 10 neonatos ≤ 24 horas de edad para el control y para cada concentración de lindano (5, 10, 15, 20 y 25 mg/L. Se realizaron tres réplicas de cada tratamiento. Se controló la inmovilización de los individuos a las 48 hs y se calcularon los valores de CL50. Los bioensayos crónicos consistieron en un diseño semi-estático, utilizando 10 neonatos menores de 24 horas de edad (uno por recipiente para el control y para cada concentración subletal del tóxico (0,1; 0,15; 0,2; 0,25 y 0,3 mg/L. Se evaluaron los efectos sobre la supervivencia y reproducción durante 21 días. El valor obtenido de CL50 48 horas fue de 5,293 ± 0,7 mg/L. Los parámetros reproductivos (neonatos por hembra, tamaño de la camada e índice de incremento natural disminuyeron al aumentar la concentración del tóxico evaluado, mientras que el inicio de la madurez sexual se retrasó, demostrando la sensibilidad de los organismos prueba al lindano.

  4. Crescimento populacional e análise isotópica de Diaphanosoma spinolosum e Ceriodaphnia cornuta (Crustacea: Cladocera, alimentadas com diferentes frações de seston natural = Population growth and stable isotope analyses of Diaphanosoma spinolosum and Ceriodaphnia cornuta (Crustacea: Cladocera fed with different seston size fractions

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    Pedro Caraballo

    2011-01-01

    Full Text Available Para definir o efeito do seston como fonte de alimento para Ceriodaphnia cornuta e Diaphanosoma spinolosum durante a enchente no lago Catalao (Amazonia Central foram desenvolvidos experimentos gin situh, utilizando a variacao natural de ƒÂ13C e ƒÂ15N comotracadores de alimento. As duas especies tiveram acesso a tres diferentes fracoes de seston (In order to define the effect of seston size fraction as a food source for Ceriodaphnia cornuta and Diaphanosoma spinolosum, in situ experiments using natural abundance of ƒÂ13C and ƒÂ15N were carried out during the rising water period in Catalao Lake. Both species werefed with three different fractions of seston from the lake (< 10, < 30 and < 60 ƒÊm and maintained in submerged 1.1 L plastic bottles for nine days. Ten individuals were put in each flask, maintaining three flasks for each fraction, for a total of 27 flasks per species. Every three days we collected three flasks and fixed the individuals for subsequent counting and observation of demographic population parameters. The organisms in the last three flasks of each fractionwere fixed for stable isotope analysis of ƒÂ13C and ƒÂ15N. Both species grew in all of the food fractions, with the best the performance coming in the < 30 ƒÊm fraction. D. spinolosum and C. cornuta showed enrichment in ƒÂ13C and ƒÂ15N, which was highest in the < 10 ƒÊm fraction for both species. These results show that the seston size fractions tested produce different population growth rates and isotopic signatures in cladocerans.

  5. Crescimento populacional e análise isotópica de Diaphanosoma spinolosum e Ceriodaphnia cornuta (Crustacea: Cladocera, alimentadas com diferentes frações de seston natural - doi: 10.4025/actascibiolsci.v33i1.7260 Population growth and stable isotope analyses of Diaphanosoma spinolosum and Ceriodaphnia cornuta (Crustacea: Cladocera fed with different seston size fractions - doi: 10.4025/actascibiolsci.v33i1.7260

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    Bruce Forsberg

    2011-02-01

    Full Text Available Para definir o efeito do seston como fonte de alimento para Ceriodaphnia cornuta e Diaphanosoma spinolosum durante a enchente no lago Catalão (Amazônia Central foram desenvolvidos experimentos “in situ”, utilizando a variação natural de δ13C e δ15N como traçadores de alimento. As duas espécies tiveram acesso a três diferentes frações de seston (D. spinolosum e C. cornuta apresentaram enriquecimento nos valores de delta;13C e δ15N, sendo maior na fração In order to define the effect of seston size fraction as a food source for Ceriodaphnia cornuta and Diaphanosoma spinolosumin, situ experiments using natural abundance of delta;13C and δ15N were carried out during the rising water period in Catalão Lake. Both species were fed with three different fractions of seston from the lake (13C and δ15N. Both species grew in all of the food fractions, with the best the performance coming in the D. spinolosum and C. cornuta showed enrichment in delta;13C and δ15N, which was highest in the < 10 µm fraction for both species. These results show that the seston size fractions tested produce different population growth rates and isotopic signatures in cladocerans.

  6. Osmia cornuta (Hymenoptera, Megachilidae) as a pollinator of pear (Pyrus communis): fruit- and seed-set

    OpenAIRE

    Maccagnani, Bettina; Ladurner, Edith; SANTI, FABRIZIO; Burgio, Giovanni

    2003-01-01

    To investigate the possibility of pollinating 'Abate Fetel' and 'Max Red Bartlett' pears with O. cornuta, different pollination treatments were compared in 1998 and 1999: (1) trees caged with O. cornuta bees; (2) open pollination - uncaged trees located at various distances from O. cornuta nesting shelters; (3) trees caged without bees. O. cornuta was the most abundant pollinator species in the orchard (97.6% of the observed insects). Caged trees pollinated by O. cornuta set significantly mor...

  7. Odorant-binding proteins and olfactory coding in the solitary bee Osmia cornuta.

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    Yin, Xue-Wei; Iovinella, Immacolata; Marangoni, Roberto; Cattonaro, Federica; Flamini, Guido; Sagona, Simona; Zhang, Long; Pelosi, Paolo; Felicioli, Antonio

    2013-08-01

    Solitary bees are major pollinators but their chemical communication system has been poorly studied. We investigated olfactory coding in Osmia cornuta from two perspectives, chemical and biochemical. We identified (E)-geranyl acetone and 2-hexyl-1,3-dioxolane, specifically secreted by females and males, respectively. A transcriptome analysis of antennae revealed 48 ORs (olfactory receptors), six OBPs (odorant-binding proteins), five CSPs (chemosensory proteins), and a single SNMP (sensory neuron membrane protein). The numbers of ORs and OBPs are much lower than in the honeybee, in particular, C-minus OBPs are lacking in the antennae of O. cornuta. We have expressed all six OBPs of O. cornuta and studied their binding specificities. The best ligands are common terpene plant odorants and both volatiles produced by the bee and identified in this work. PMID:23512006

  8. Foraging behavior and pollinating effectiveness of Osmia cornuta (Hymenoptera: Megachilidae) and Apis mellifera (Hymenoptera: Apidae) on "Comice" pear

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    Monzón, Víctor; Bosch, Jordi; Retana, Javier

    2004-01-01

    We studied the pollinating effectiveness of Osmia cornuta and Apis mellifera on 'Comice' pear. Osmia cornuta visited more flowers per minute (13.8) than A. mellifera (7.1-9.8). Both species visited similar numbers of flowers per tree (6.7-7.9), and switched rows with similar frequency (4.0-7.9%). Rate of stigma contact was 98.7% for O. cornuta, 51.8% for A. mellifera pollen-nectar foragers, and 19.0% for A. mellifera nectar foragers. Fruit-set in flowers visited once was 28.9, 29.3, and 12.9%...

  9. Supercooling points and diapause termination in overwintering adults of orchard bees Osmia cornuta and O. rufa (Hymenoptera: Megachilidae).

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    Krunić, M D; Stanisavljević, L Z

    2006-06-01

    The orchard bee species Osmia cornuta (Latreille) and O. rufa (Linnaeus) are both European in distribution. Osmia cornuta is distributed in the central and southern half of the continent, while O. rufa is distributed additionally in more northern parts of Europe, including Great Britain. These bees over-winter in cocoons as diapausing adults. The freezing temperatures of overwintering adults of O. cornuta and O. rufa during diapause are similar: -30 degrees C to -24 degrees C and -31 degrees C to -26 degrees C, respectively. However, there are differences in the termination of their diapause. Under natural conditions in the wider area of Belgrade, O. rufa appears in spring about two weeks later than O. cornuta. PMID:16768821

  10. Toxicity of Spirotetramat on Solitary Bee Larvae, Osmia Cornuta (Hymenoptera: Megachilidae), in Laboratory Conditions

    OpenAIRE

    Sgolastra Fabio; Tosi Simone; Medrzycki Piotr; Porrini Claudio; Burgio Giovanni

    2015-01-01

    In this paper we assessed, under laboratory conditions, the toxicity of an active substance on solitary bee larvae of Osmia cornuta (Hymenoptera: Megachilidae). A field-realistic dose of the systemic insecticide spirotetramat was applied to the mass provisions. The insecticide’s effects on several life-cycle parameters were studied in males and females. Our results showed a significantly shorter post-emergence longevity in bees exposed to spirotetramat during the larval stage, compared to the...

  11. Development and characterization of 11 microsatellite loci for the Mona Island iguana (Cyclura cornuta stejnegeri)

    OpenAIRE

    Pérez-Buitrago, Néstor; Rosas G., Keysa; Acevedo-Rodríguez, Pedro; Funk, S. M.; McMillan, Owen

    2008-01-01

    We isolated and characterized 11 microsatellite loci in the Mona Island iguana (Cyclura cornuta stejnegeri). Eleven loci exhibit moderate to high allelic diversity (two to 12 alleles, mean = 4.5) and polymorphism (mean observed heterozygosity, 0.56; range, 0.26 to 0.78) in 41 adults. This marker set has low probability of identity and high parentage exclusion power and will be suitable for studies of paternity, social organization and relatedness in this species.

  12. Tiny but complex - interactive 3D visualization of the interstitial acochlidian gastropod Pseudunela cornuta (Challis, 1970

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    Heß Martin

    2009-09-01

    Full Text Available Abstract Background Mesopsammic acochlidians are small, and organ complexity may be strongly reduced (regressive evolution by progenesis, especially in microhedylacean species. The marine interstitial hedylopsacean Pseudunela cornuta (Challis, 1970, however, was suggested as having a complex reproductive system resembling that of much larger, limnic and benthic species. The present study aims to reconstruct the detailed anatomy and true complexity of P. cornuta from serial, semithin histological sections by using modern computer-based 3D visualization with Amira software, and to explain it in an evolutionary context. Results Our results demonstrate considerable discordance with the original species description, which was based solely on paraffin sections. Here, we show that the nervous system of P. cornuta has paired rhinophoral, optic and gastro-oesophageal ganglia, three distinct ganglia on the visceral nerve cord, and a putative osphradial ganglion, while anterior accessory ganglia are absent. The presence of an anal genital cloaca is clearly rejected and the anus, nephropore and gonopore open separately to the exterior; the circulatory and excretory systems are well-differentiated, including a two-chambered heart and a complex kidney with a long, looped nephroduct; the special androdiaulic reproductive system shows two allosperm receptacles, three nidamental glands, a cavity with unknown function, as well as highly complex anterior copulatory organs with two separate glandular and impregnatory systems including a penial stylet that measures approximately a third of the whole length of the preserved specimen. Conclusion In spite of its small body size, the interstitial hermaphroditic P. cornuta shows high complexity regarding all major organ systems; the excretory system is as differentiated as in species of the sister clade, the limnic and much larger Acochlidiidae, and the reproductive system is by far the most elaborated one ever observed

  13. Effect of pre-wintering and wintering temperature regimes on weight loss, survival, and emergence time in the mason bee Osmia cornuta (Hymenoptera: Megachilidae)

    OpenAIRE

    Bosch, Jordi; Kemp, William

    2004-01-01

    Osmia cornuta adults require exposure to wintering temperatures followed by incubation in the spring to emerge. We studied winter survival, weight loss, emergence time, and post-emergence longevity in O. cornuta exposed to a variety of pre-wintering and wintering treatments. Few bees emerged after exposure to wintering durations

  14. Combattere il colpo di fuoco con l’aiuto di Osmia cornuta

    OpenAIRE

    Bettina, Maccagnani; Roberto, Ferrari; Marco, Pozzati

    2014-01-01

    For Osmia cornuta, a low cost dispenser was developed. Therefore, per nest, 50 females and 100 males in their cocoons were released. After the mating and when the females started nesting, a metal grid was installed in front of the nest to oblige the females to get out passing through the dispenser. A free space above the dispenser gave female bees the possibility of returning to their nest without crossing the dispenser. Although some time was needed to learn how to enter the nest using the f...

  15. Microbiota associated with pollen, bee bread, larvae and adults of solitary bee Osmia cornuta (Hymenoptera: Megachilidae).

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    Lozo, J; Berić, T; Terzić-Vidojević, A; Stanković, S; Fira, D; Stanisavljević, L

    2015-08-01

    Using cultivation-dependant method, we isolated 184 strains from fresh and old bee bread, pollen, larvae and adults of solitary bee Osmia cornuta. The 16S rDNA sequencing of 79 selected isolates gave the final species-specific identification of strains. Phylogenetic analysis indicated that microbiota isolated from five different sources were represented with 29 species within three different phyla, Firmicutes with 25 species, Actinobacteria with only one species and Proteobacteria with three species of Enterobacteriaceae. Bacterial biodiversity presented with Shannon-Wiener index (H') was highest in the alimentary tract of adults and old bee bread (H' = 2.43 and H' = 2.53, respectively) and in the same time no dominance of any species was scored. On the contrary, results obtained for Simpson index (D) showed that in pollen samples the dominant species was Pantoea agglomerans (D = 0.42) while in fresh bee bread that was Staphylococcus sp. (D = 0.27). We assume that microbial diversity detected in the tested samples of solitary bee O. cornuta probably come from environment. PMID:25895542

  16. [Screening probiotic endophytic bacteria from medicinal plant flex cornuta and the phytopathogen-inhibiting effect].

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    Zhao, Long-fei; Xu, Ya-jun; Lai, Xin-he; Kou, Tian-chao; Yan, Jun-li; Zhou, Pei-pei; Fan, Shan-shan; Yan, Yong-feng

    2015-05-01

    Culturable endophytic bacteria were isolated from medicinal plant Ilex cornuta by plate-spreading method, strains with strong inhibitory effect on phytopathogen were screened by confrontation culture and fermentation filtrate culture methods, and the morphological changes of phytopathogen hyphae treated with endophytic bacteria were examined by microscopy and micrograph. Their phylogenetic relationships were determined by homology analysis of the 16S rDNA sequences of PCR products and the taxonomic status of the selected strains was determined based on their morphology, physiology, biochemical test results and 16S rDNA sequence analysis. A total of 85 endophytic bacteria were isolated from the healthy roots, stems, leaves and fruits of I. cornuta, and 10 strains of them showed strong inhibitory effect on Alternaria alternata, Magnaporthe grisea, Fusarium oxysporum, and were preliminarily identified belonging to four genera and seven species. Three strains with the strongest inhibitory effect, GG78 (60.3%), GG31 (48.1%) and GG13 (61.0%) belonged to Enterobacter cloacae, Enterobacter ludwigii and Bacillus cereus, respectively. Microscopic analyses showed that the inhibited phytopathogen hyphae became deformed, distorted, and partially expanded forming plasma concentration and hair-like branch on the hyphae base. These morphological changes could be caused by the extracellular metabolic substances secreted by the endophytic bacteria, such as antibiotics, hydrolytic enzymes, alkaloids and so on. PMID:26571677

  17. SARS Basics

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    ... Laboratory Testing & Specimens SARS-Associated Coronavirus (SARS-CoV) Sequencing Informed Consent for Laboratory Testing Specimen Collection and ... person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, ...

  18. The neonicotinoid clothianidin interferes with navigation of the solitary bee Osmia cornuta in a laboratory test.

    Science.gov (United States)

    Jin, Nanxiang; Klein, Simon; Leimig, Fabian; Bischoff, Gabriela; Menzel, Randolf

    2015-09-01

    Pollinating insects provide a vital ecosystem service to crops and wild plants. Exposure to low doses of neonicotinoid insecticides has sub-lethal effects on social pollinators such as bumblebees and honeybees, disturbing their navigation and interfering with their development. Solitary Hymenoptera are also very important ecosystem service providers, but the sub-lethal effects of neonicotinoids have not yet been studied well in those animals. We analyzed the ability of walking Osmia to remember a feeding place in a small environment and found that Osmia remembers the feeding place well after 4 days of training. Uptake of field-realistic amounts of the neonicotinoid clothianidin (0.76 ng per bee) altered the animals' sensory responses to the visual environment and interfered with the retrieval of navigational memory. We conclude that the neonicotinoid clothianidin compromises visual guidance and the use of navigational memory in the solitary bee Osmia cornuta. PMID:26206356

  19. Longevity and reproduction of Ceriodaphnia dubia in receiving waters

    International Nuclear Information System (INIS)

    Seven-day tests with Ceriodaphnia dubia are commonly used to estimate toxicity of effluents or receiving waters but can sometimes yield no toxicity outcomes even if pollutants are present. The authors conducted two sets of full life-cycle tests with C. dubia to (1) determine whether tests with longer exposure periods to low concentrations of contaminants in ambient water might reveal evidence of toxicity that could not be discerned from 7-d tests and (2) determine the relative importance of water quality versus food as factors influencing C. dubia longevity and reproduction. In the first set of tests, C. dubia was reared in diluted mineral water (a negative control), water from a stream impacted by coal fly-ash, or water from a retention basin containing sediments contaminated with mercury, other metals, and polychlorinated biphenyls. The second set of tests used water from the retention basin only. Before testing, though, water in the second set of tests was either filtered or not filtered, and food was either added or not added. Ceriodaphnia dubia longevity and reproduction did not differ much among the three water types in the first set of tests, but both longevity and reproduction were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia appeared to be relatively insensitive to general water quality factors but sensitive to food-related factors. In five of the six full life-cycle tests, lifetime reproduction by C. dubia could not be reliably predicted from reproduction data from the first 7 d of testing. The increase in predictability of lifetime reproduction of C. dubia as a function of test duration also differed among water types in the first set of tests and among treatments in the second set of tests. This, it may not be possible to reliably extrapolate the results of 7-d tests with C. dubia to longer time scales

  20. Natal dispersal, home range and habitat use of hatchlings of the Mona Island iguana (Cyclura cornuta stejnegeri)

    OpenAIRE

    Pérez-Buitrago, Néstor; Sabat, Alberto

    2007-01-01

    In the last two decades our knowledge of the biology of the highly threatened rock iguanas (Cyclura) has been expanding. However, most studies have focused on the adults and none has been conducted to document the biology of the younger stages. In some instances, such as the Mona Island iguana (Cyclura cornuta stejnegeri), the biology of young stages has been overlooked due to their low relative abundance in the population. The causes of this population trait remain unknown and ...

  1. Toxicity of Spirotetramat on Solitary Bee Larvae, Osmia Cornuta (Hymenoptera: Megachilidae, in Laboratory Conditions

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    Sgolastra Fabio

    2015-12-01

    Full Text Available In this paper we assessed, under laboratory conditions, the toxicity of an active substance on solitary bee larvae of Osmia cornuta (Hymenoptera: Megachilidae. A field-realistic dose of the systemic insecticide spirotetramat was applied to the mass provisions. The insecticide’s effects on several life-cycle parameters were studied in males and females. Our results showed a significantly shorter post-emergence longevity in bees exposed to spirotetramat during the larval stage, compared to the control. The observed reduction in longevity was 18 and 15%, respectively, in males and females. Mortality rate and other biological traits (larval and spinning duration, emergence time, food/body conversion rate did not show significant differences between the two treatments. The method described in this study can be used to test the effects of toxic substances (i.e. agrochemicals on bees. Moreover, it can constitute a basis for the development of a standardised protocol in the first tier of the Environmental Risk Assessment for solitary bees.

  2. From the anther to the proctodeum: Pear (Pyrus communis) pollen digestion in Osmia cornuta larvae.

    Science.gov (United States)

    Nepi, Massimo; Cresti, Laura; Maccagnani, Bettina; Ladurner, Edith; Pacini, Ettore

    2005-07-01

    Modifications of the pollen grains of Pyrus communis Linneaus that occur during the digestion by Osmia cornuta (Latreille) larvae were studied histochemically. We compared the features of the pollen grains found in the anthers, in the larval cell provisions and in the alimentary canal of the 5th instar larvae. Modifications were already evident in the provisions and consisted of protoplast protrusions through the apertures and a decrease in the number of starch-containing pollen grains. After pollen grains were ingested by the larvae, the protoplast appeared retracted from the pollen wall. Pollen digestion began in the anterior part of the midgut, where we observed: (1) disorganised intine at the apertures; (2) disappearance of DAPI staining of nuclear pollen DNA; (3) fewer pollen grains containing starch than in the anthers; (4) some empty pollen grains. Pollen grains in the proctodeum appeared extremely compressed and crushed. Some grains appeared to be unaffected by the digestive process. We hypothesise that the protrusion of the intine and of the protoplast from the apertures in bee provisions could be considered a kind of pre-treatment necessary to initiate the digestion process in the larval alimentary canal. PMID:16105552

  3. Life-cycle testing of receiving waters with Ceriodaphnia dubia

    International Nuclear Information System (INIS)

    Seven-day tests with Ceriodaphnia are commonly used to estimate the toxicity of effluents or receiving waters, but may yield no toxicity outcomes even when pollutants are present (a possible type II error). The authors conducted two sets of full life-cycle tests with C. dubia to (1) see if tests with longer exposure periods revealed evidence for toxicity that might not be evident from shorter tests, and (2) determine the relative importance of water quality versus food as factors influencing C. dubia reproduction. In the first set of tests, daphnids were reared in diluted mineral water (control), water from a stream impacted by coal fly-ash, or water from a mercury-contaminated retention basin. The second set of tests used water from the retention basin only, but this water was either filtered or not filtered, and food was either added or not added. C. dubia survival and reproduction did not differ much among the three waters in the first set of tests. However, both parameters were strongly affected by the filtering and food-addition treatments in the second set of tests. Thus, C. dubia seems to be moderately insensitive to general water-quality factors, but quite sensitive to food-related parameters. Regression analysis showed that the predictability of life-time reproduction of C. dubia from 7-day test results was low in five of six cases. The increase in predictability as a function of test duration also differed among water types (first set of tests), and among treatments (second set of tests). Thus, 7-day tests with C. dubia may be used to quantify water-quality problems, but it may not be possible to reliably extrapolate the results of such tests to longer time scales

  4. EFFECTIVE CONCENTRATIONS OF 6 CONTAMINANTS TO LEMMA MINOR, PIMEPHALES PROMELA, DAPHNIA MAGNA, AND CERIODAPHNIA DUBIA

    Science.gov (United States)

    The research presented here resulted in EC50 and LOEC values for the contaminants copper, cadmium, diazinon, atrazine, and cyanide to the species Lemna Minor, Pimephales promelas, Daphnia magna, and Ceriodaphnia dubia. Observed values were used as benchmarks for assessing the se...

  5. Ceriodaphnia and Chironomus in situ toxicity tests assessing the wastewater treatment efficacy of constructed wetlands

    International Nuclear Information System (INIS)

    In situ toxicity tests were designed for Ceriodaphnia dubia and Chironomus tentans as part of a larger study designed to assess the effectiveness of constructed wetlands for the treatment of wastewater produced by oil production at Suncor OSG. The artificial wetlands were 50m long by 3m wide, with three replicates of the control and the treatment. Each wetland had four sample sites equidistant along its length, creating a gradient of treatment from site A being the most toxic to site D being the least toxic. Each test was conducted twice during the summer of 1994. Both the Ceriodaphnia and Chironomus test cages were a flow through design to allow for maximal exposure to the water within the wetlands. Mortality and reproduction were used as endpoints for Ceriodaphnia, whereas mortality and growth were used as endpoints for the Chironomus test. Test durations were fifteen and ten days respectively. Chironomus had very high mortality along the entire wetlands whereas Ceriodaphnia survival and fecundity increased along the length of the treatment wetlands. Both organisms had low mortality and high growth/fecundity in the control wetlands

  6. Reproductive success and mortality rates of Ceriodaphnia dubia maintained in water from Upper Three Runs, Pen Branch, and Fourmile Branch

    International Nuclear Information System (INIS)

    It is anticipated that the new SRS NPDES permit will require toxicity testing of at numerous outfalls and receiving streams, using the standard test species, Ceriodaphnia dubia. Because SRS surface waters differ markedly from the standard culture water that is used for Ceriodaphnia, studies were undertaken to determine if unimpacted SRS surface waters will support this species. Three SRS surface waters were evaluated; Upper Three Runs at Road 8-1, Pen Branch at Road B, and Fourmile Branch at Road F. Toxicity tests were performed monthly on each water source for eleven months. All three water sources exhibited varying degrees of toxicity to Ceriodaphnia, with Pen Branch being the least toxic and Fourmile Branch being the most toxic. These results indicate that if in-stream toxicity testing is required, it may not be possible to separate the naturally occurring toxic effects of the receiving water from possible toxic effects of SRS effluents

  7. Effect of organic media on growth and development of patiola F1 horned violet (Viola cornuta L.

    Directory of Open Access Journals (Sweden)

    Dorota Janicka

    2013-04-01

    Full Text Available The specificity of horticultural production makes it possible to use substrates based on compost from municipal and industrial waste, particularly in the cultivation of ornamental plants. Experiments were conducted in the years 2005–2007. Six horned violet cultivars (Viola cornuta  L. from Patiola F1 group and four substrates were used in them: I – sphagnum peat; II – substrate from peat and compost 1 (1:1 v/v; III – substrate from peat and compost 2 (1:1 v/v; IV – coconut fibre. Compost 1 was prepared using municipal sewage sludge (35%, potato pulp (35% and straw (30%. Compost 2 was prepared using municipal sewage sludge (35%, potato pulp (35% and sawdust (30%. Composts after 10 months of composting were used in the research. The addition of municipal sewage sludge composts did not cause observable adverse changes in plants grown. Composts made from municipal sewage sludge are rich in nutrients. Plants that are grown in substrates with the addition of composts and in a peat substrate grow and develop properly without the necessity of introducing top dressing.

  8. Interaction of chemical cues from fish tissues and organophosphorous pesticides on Ceriodaphnia dubia survival

    International Nuclear Information System (INIS)

    Cladocera are frequently used as test organisms for assessing chemical and effluent toxicity and have been shown to respond to stimuli and cues from potential predators. In this study, the interactive effects of visual and chemical cues of fish and two organophosphorous pesticides on survival of Ceriodaphnia dubia were examined. A significant chemical cue (homogenized Pimephales promelas) and malathion interaction was observed on C. dubia survival (P = 0.006). Chemical cue and 2.82 μg/L malathion resulted in a 76.0% reduction in survival compared to malathion alone (P < 0.01). Furthermore, potentiation of malathion toxicity varied based on the source of chemical cues (i.e., epithelial or whole body). It is unclear in this study whether these chemical cues elicited a predation-related stress in C. dubia. Future research should examine the mechanism of this interaction and determine what role, if any, stress responses by C. dubia might play in the interaction. - Potentiation of organophosphorous pesticide toxicity to Ceriodaphnia dubia by fathead minnow (Pimephales promelas) chemical cues was observed

  9. Usnea cornuta Körb. and Usnea glabrescens (Vainio) Vainio sens. Lat.: Species to be protected in the peninsula of Edough (Algeria).

    Science.gov (United States)

    Fekroune Chaker, A

    2016-01-01

    In the Mediterranean region, Edough Peninsula (Algerian Northeast) has a significant procession of rare plant species biogeographical interest. This communication is based on specimens collected by the author during the realization of a lichen herbarium when her attention was attracted by the striking presence of a fruticose lichen of Usnea genus, on a hawthorn at the entrance of a private neglected garden. One of the harvested species proved to be after identification, Usnea glabrescens (Vainio) Vainio sens. Lat. A second species was harvested meanwhile a few meters away, on a cork oak and identified as Usnea cornuta Körber species ever recorded in Algeria before. PMID:27262806

  10. Keynote presentation : SAR systems

    NARCIS (Netherlands)

    Halsema, D. van; Otten, M.P.G.; Maas, A.P.M.; Bolt, R.J.; Anitori, L.

    2011-01-01

    Synthetic Aperture Radar (SAR) systems are becoming increasingly important sensors in as well the military environment as in the civilian market. In this keynote presentation an overview will be given over more than 2 decades of SAR system∼ and SAR application development at TNO in the Netherlands.

  11. MULTIGENERATIONLIFE-SPAN TESTS OF THE NUTRITIONAL ADEQUACY OF SEVERAL DIETS AND CULTURE WATERS FOR CERIODAPHNIA DUBIA

    Science.gov (United States)

    The effects of four diets [Chlamydomonas reinhardtii, Selenastrum capricornutum, yeast-trout chow-Cerophyl (YTC) and YTC plus S. capricornutum] and two reconstituted waters on the vitality and fecundity of five to six life-span generations of Ceriodaphnia dubia were determined. T...

  12. SARS Immunity and Vaccination

    Institute of Scientific and Technical Information of China (English)

    Minsheng Zhu

    2004-01-01

    Severe acute respiratory syndrome (SARS) is a serious and fatal infectious disease caused by SARS coronavirus (SARS-Cov), a novel human coronavirus. SARS-Cov infection stimulates cytokines (e.g., IL-10,IFN-γ, IL-1, etc.) expression dramatically, and T lymphocytes and their subsets CD4+ and CD8+ T cells are decreased after onset of the disease. SARS-specific IgG antibody is generated in the second week and persists for a long time, whereas IgM is expressed transiently. The spike protein and neucleocapsid protein are most abundant in SARS-Cov and contribute dominantly to the antibody production during the course of disease. Spike protein, especially the ACE-2 binding region (318-510aa) is capable of producing neutralizing antibody to SARS-Cov. Neucleocapsid protein induces protective specific CTL to SARS-Cov. Therefore, applications with spike subunit, neucleocapsid subunit as well as inactivated SARS-Cov are three prospective vaccination strategies for SARS.

  13. SARS Immunity and Vaccination

    Institute of Scientific and Technical Information of China (English)

    MinshengZhu

    2004-01-01

    Severe acute respiratory syndrome (SARS) is a serious and fatal infectious disease caused by SARS coronavirus (SARS-Cov), a novel human coronavirus. SARS-Cov infection stimulates cytokines (e.g., IL-10,IFN-γ, IL-1, etc.) expression dramatically, and T lymphocytes and their subsets CD4+ and CD8+ T cells are decreased after onset of the disease. SARS-specific IgG antibody is generated in the second week and persists for a long time, whereas IgM is expressed transiently. The spike protein and neucleocapsid protein are most abundant in SARS-Cov and contribute dominantly to the antibody production during the course of disease.Spike protein, especially the ACE-2 binding region (318-510aa) is capable of producing neutralizing antibody to SARS-Cov. Neucleocapsid protein induces protective specific CTL to SARS-Cov. Therefore, applications with spike subunit, neucleocapsid subunit as well as inactivated SARS-Cov are three prospective vaccination strategies for SARS.

  14. Effects of depleted uranium on the health and survival of Ceriodaphnia dubia and Hyalella azteca

    Science.gov (United States)

    Kuhne, W.W.; Caldwell, C.A.; Gould, W.R.; Fresquez, P.R.; Finger, S.

    2002-01-01

    Depleted uranium (DU) has been used as a substitute for the fissionable enriched uranium component of atomic weapons tested at Los Alamos National Laboratory (LANL) (Los Alamos, NM, USA) since the early 1950s, resulting in considerable concentrations of DU in the soils within the test sites. Although the movement of DU into major aquatic systems has been shown to be minimal, there are many small-order ephemeral streams and areas of standing water in canyons throughout LANL that may be affected by inputs of DU via runoff, erosion, and leaching. Ninety-six-hour acute and 7-d chronic toxicity assays were conducted to measure the toxicity of DU on survival and reproduction of Ceriodaphnia dubia. A 14-d water-only assay was conducted to measure survival and growth of Hyalella azteca. The estimated median lethal concentration (LC50) to produce 50% mortality of the test population for the 96-h Ceriodaphnia dubia assay was 10.50 mg/L. Reproductive effects occurred at a lowest-observable-effect concentration ???3.91 mg/L with a no-observable-effect concentration of 1.97 mg/L. The estimated 14-d LC50 for the Hyalella azteca assay was 1.52 mg/L No significant relationship was detected between growth and DU concentrations. Concentrations at which toxicity effects were observed in this study for both invertebrates exceeded concentrations of total uranium observed in runoff from LANL lands. Thus, it is likely that current runoff levels of uranium do not pose a threat to these types of aquatic invertebrates.

  15. Toxic effects of Pseudanabaena tenuis (Cyanobacteria) on the cladocerans Daphnia magna and Ceriodaphnia dubia Efectos tóxicos de Pseudanabaena tenuis (Cyanobacteria) en los cladóceros Daphnia magna y Ceriodaphnia dubia

    OpenAIRE

    Roxana Olvera-Ramírez; Carla Centeno-Ramos; Fernando Martínez-Jerónimo

    2010-01-01

    Some cyanobacteria can produce toxins that affect the aquatic biota and represent a human health risk. The cyanobacterium Pseudanabaena tenuis was isolated from the Valle de Bravo dam, and cultured in the laboratory under controlled conditions. We determined the acute toxic effects and performed a chronic (consumption) test in the cladocerans Daphnia magna (a reference test organism) and Ceriodaphnia dubia (a cosmopolitan species). To determine acute toxicity, three exposure ways were assayed...

  16. Development and validation of a chronic copper biotic ligand model for Ceriodaphnia dubia

    International Nuclear Information System (INIS)

    A biotic ligand model (BLM) to predict chronic Cu toxicity to Ceriodaphnia dubia was developed and tested. The effect of cationic competition, pH and natural organic matter complexation of Cu was examined to develop the model. There was no effect of cationic competition using increasing Ca and Na concentrations in our exposures. However, we did see a significant regression of decreasing toxicity (measured as the IC25; concentration at which there was a 25% inhibition of reproduction) as Mg concentration increased. However, taking into account the actual variability of the IC25 and since the relative increase in IC25 due to additional Mg was small (1.5-fold) Mg competition was not included in the model. Changes in pH had a significant effect on Cu IC25, which is consistent with proton competition as often suggested for acute BLMs. Finally, natural organic matter (NOM) was added to exposures resulting in significant decreases in toxicity. Therefore, our predictive model for chronic Cu toxicity to C. dubia includes the effect of pH and NOM complexation. The model was validated with Cu IC25 data generated in six natural surface waters collected from across Canada. Using WHAM VI, we calculated Cu speciation in each natural water and using our model, we generated 'predicted' IC25 data. We successfully predicted all Cu IC25 within a factor of 3 for the six waters used for validation

  17. Comparative aquatic toxicity evaluation of 2-(thiocyanomethylthio)benzothiazole and selected degradation products using Ceriodaphnia dubia.

    Science.gov (United States)

    Nawrocki, S T; Drake, K D; Watson, C F; Foster, G D; Maier, K J

    2005-04-01

    2-(Thiocyanomethylthio)benzothiazole (TCMTB) is a biocide used in the leather, pulp and paper, and water-treatment industries. TCMTB may enter aquatic ecosystems during its manufacture and use. TCMTB is environmentally unstable; therefore, it is important to evaluate the toxicity of the more persistent degradation products. This study compared the toxicity of TCMTB with its degradation products 2-mercaptobenzothiazole (2-MBT), 2-(methylthio)benzothiazole (MTBT), benzothiazole (BT), and 2-hydroxybenzothiazole (HOBT). Toxicity was determined using Ceriodaphnia dubia 48-hour acute and 7-day chronic test protocols. TCMTB was the most toxic compound evaluated in both the acute and chronic tests with EC50s of 15.3 and 9.64 microg/L, respectively. 2-MBT, the first degradation product, was the second most toxic compound with acute and chronic EC50s of 4.19 and 1.25 mg/L, respectively. The toxicity of MTBT and HOBT were similar with acute EC50s of 12.7 and 15.1 mg/L and chronic EC50s of 6.36 and 8.31 mg/L, respectively. The least toxic compound was BT with acute and chronic EC50s of 24.6 and 54.9 mg/L, respectively. TCMTB was orders of magnitude more toxic than its degradation products. Toxicity data on these benzothiazole degradation products is important because of concerns regarding their release, degradation, persistence, and non-target organism effects in aquatic ecosystems. PMID:15750776

  18. Effects of diet on seven-day Ceriodaphnia dubia toxicity tests

    Energy Technology Data Exchange (ETDEWEB)

    Cerda, B.; Olive, J.H. (Univ. of Akron, OH (United States))

    1993-06-01

    The purpose of this study was to evaluate the effects of four diets on the results of seven-day Ceriodaphnia dubia toxicity tests. Survival and reproduction were used as indices to detect the sensitivity of this species to acute and chronic copper stress. All toxicity tests were conducted using the moderately hard reconstituted water recommended in 1989 by the U.S. Environmental Protection Agency. Diet differentially affected the acute and chronic toxicity of copper. Daphnids fed Selenastrum capricornutum (alga) showed the greatest sensitivity, followed by those fed the alga Chlamydomonas reinhardti, then by animals fed a Yeast-Cerophyll[sup TM]-Trout Food (YCTF) mixture plus Selenastrum, and finally by animals fed YCTF alone. These differences may result from the poor nutritional adequacy of Selenastrum when fed alone, the different caloric contents of the diets, the increased toxicant uptake by the organisms through ingestion of copper-laden algal cells, and/or copper ions sequestered by fats and insoluble substances in YCTF. The authors recognize that diet is an important variable in seven-day toxicity tests, and that the selection of a diet should not be based only on its effects on long-term culturing of C. dubia, but also on its possible effects on test results.

  19. Coronaviruses (MERS and SARS)

    Science.gov (United States)

    ... the globe have initiated studies to understand the Middle East respiratory syndrome coronavirus (MERS-CoV)—and how to stop it. Coronaviruses About Coronaviruses Middle East Respiratory Syndrome (MERS) Severe Acute Respiratory Syndrome (SARS) ...

  20. Cetacean SAR monitoring table

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NMFS prepares marine mammal stock assessment reports (SARs) as part of MMPA section 117 requirements. The reports are prepared in consultation with one or more of...

  1. Individual and binary toxicity of anatase and rutile nanoparticles towards Ceriodaphnia dubia.

    Science.gov (United States)

    Iswarya, V; Bhuvaneshwari, M; Chandrasekaran, N; Mukherjee, Amitava

    2016-09-01

    Increasing usage of engineered nanoparticles, especially Titanium dioxide (TiO2) in various commercial products has necessitated their toxicity evaluation and risk assessment, especially in the aquatic ecosystem. In the present study, a comprehensive toxicity assessment of anatase and rutile NPs (individual as well as a binary mixture) has been carried out in a freshwater matrix on Ceriodaphnia dubia under different irradiation conditions viz., visible and UV-A. Anatase and rutile NPs produced an LC50 of about 37.04 and 48mg/L, respectively, under visible irradiation. However, lesser LC50 values of about 22.56 (anatase) and 23.76 (rutile) mg/L were noted under UV-A irradiation. A toxic unit (TU) approach was followed to determine the concentrations of binary mixtures of anatase and rutile. The binary mixture resulted in an antagonistic and additive effect under visible and UV-A irradiation, respectively. Among the two different modeling approaches used in the study, Marking-Dawson model was noted to be a more appropriate model than Abbott model for the toxicity evaluation of binary mixtures. The agglomeration of NPs played a significant role in the induction of antagonistic and additive effects by the mixture based on the irradiation applied. TEM and zeta potential analysis confirmed the surface interactions between anatase and rutile NPs in the mixture. Maximum uptake was noticed at 0.25 total TU of the binary mixture under visible irradiation and 1 TU of anatase NPs for UV-A irradiation. Individual NPs showed highest uptake under UV-A than visible irradiation. In contrast, binary mixture showed a difference in the uptake pattern based on the type of irradiation exposed. PMID:27522033

  2. Esfenvalerate toxicity to the cladoceran Ceriodaphnia dubia in the presence of green algae, Pseudokirchneriella subcapitata.

    Science.gov (United States)

    Brander, Susanne M; Mosser, Christopher M; Geist, Juergen; Hladik, Michelle L; Werner, Inge

    2012-11-01

    The presence of phytoplankton, like other particulate organic matter, can interfere with the effects of hydrophobic contaminants such as pyrethroid pesticides. However, the reduction or elimination of toxicity by algae added as food during testing is not taken into account in standard US EPA whole effluent toxicity (WET) zooplankton tests. On the other hand, WET test conditions may overestimate toxicity of such compounds in highly productive surface waters with high concentrations of detritus and other particulate matter. In addition, WET tests do not measure impaired swimming ability or predator avoidance behavior as an indicator of increased mortality risk. This study used a modified version of the US EPA WET Ceriodaphnia dubia acute test to investigate the effects of phytoplankton on toxicity of the pyrethroid insecticide, esfenvalerate. Animals were exposed simultaneously to different concentrations of esfenvalerate and green algae (Pseudokirchneriella subcapitata). Mortality and predation risk were recorded after 4 and 24 h. Algae at or below concentrations specified in the WET protocol significantly reduced mortality. Regardless, organisms exposed to esfenvalerate were unable to avoid simulated predation in the presence of algae at any concentration. After 12 h, esfenvalerate adsorbed to algae represented 68-99 % of the total amount recovered. The proportion of algae-bound insecticide increased with algal concentration indicating that conclusions drawn from toxicity tests in which algae are added as food must be interpreted with caution as the dissolved fraction of such hydrophobic contaminants is reduced. Additionally, our results strongly suggest that the EPA should consider adding ecologically-relevant endpoints such as swimming behavior to standard WET protocols. PMID:22975895

  3. Bioaccumulation of Fe2O3(magnetic) nanoparticles in Ceriodaphnia dubia

    International Nuclear Information System (INIS)

    While nano-Fe2O3(magnetic) is generally considered non-toxic, it could serve as a carrier of other toxic chemicals such as As(V) and enhance their toxicity. The bioaccumulation of nano-Fe2O3(m) with different exposure times, NP concentrations, and pH conditions was investigated using Ceriodaphnia dubia (C. dubia) as the model organism. Under natural pH conditions, C. dubia significantly accumulated nano-Fe2O3(m) in the gut, with the maximum accumulation being achieved after 6 h of exposure. The concentration of nano-Fe2O3 also impacted its accumulation, with the maximum uptake occurring at 20 mg/L or more. In addition, the highest bioaccumulation occurred in a pH range of 7–8 where the highest feeding rate was reported, confirming that the ingestion of NPs is the main route of nano-Fe2O3(m) bioaccumulation. In a clean environment without NPs, depuration of nano-Fe2O3(m) occurred, and food addition accelerated the depuration process. - Highlights: ► Nano-Fe2O3(m) enhances the toxicity of As(V). ► C. dubia significantly accumulate nano-Fe2O3(m) through ingestion. ► The bioaccumulation of nano-Fe2O3(m) is affected by time, NP concentration, and pH. ► Food addition accelerates the depuration process of accumulated nano-Fe2O3(m). - Nano-Fe2O3(m) could enhance the toxicity of As(V) due to the significant accumulation of nano-Fe2O3(m) along with sorbed As(V) by C. dubia through ingestion.

  4. Variation in toxicity response of Ceriodaphnia dubia to Athabasca oil sands coke leachates.

    Science.gov (United States)

    Puttaswamy, Naveen; Turcotte, Dominique; Liber, Karsten

    2010-07-01

    Coke from the Athabasca (Alberta, Canada) oil sands operations may someday be integrated into reclamation landscapes. It is hypothesized that the metals associated with the solid coke may leach into the surrounding environment. Therefore, the main objectives of this study were to characterize the toxicity and chemistry of coke leachates collected from two field lysimeters (i.e. shallow lysimeter and deep lysimeter) over a period of 20months, as well as from other oil sands coke storage sites. In addition, a batch renewal leaching of coke was conducted to examine the rate of metals release. Chronic toxicity of key metals (e.g. Al, Mn, Ni and V) found in lysimeter coke leachate was evaluated separately. Toxicity test results revealed that whole coke leachates (100% v/v) were acutely toxic to Ceriodaphnia dubia; the 7-day LC50 values were always coke leachate. The deep lysimeter leachate was generally more toxic than the shallow lysimeter leachate, likely because of significantly higher concentrations of vanadium (V) found in the deep lysimeter leachate at all sampling times. Vanadium concentrations were higher than all other metals found in the leachate from both lysimeters, and in the batch renewal leaching study. Furthermore, V found in leachates collected from other oil sands field sites showed a concentration-response relationship with C. dubia survival. Mass balance calculations indicated that 94-98% of potentially leachable V fraction was still present in the coke from two field lysimeters. Evidence gathered from these assessments, including toxic unit (TU) calculations for the elements of concern, suggests that V was the likely cause of toxicity of the deep lysimeter leachate, whereas in the shallow lysimeter leachate both Ni and V could be responsible for the observed toxicity. PMID:20553931

  5. Fractionation of fulvic acid by iron and aluminum oxides: influence on copper toxicity to Ceriodaphnia dubia

    Science.gov (United States)

    Smith, Kathleen S.; James F. Ranville; Emily K. Lesher; Daniel J. Diedrich; Diane M. McKnight; Ruth M. Sofield

    2014-01-01

    This study examines the effect on aquatic copper toxicity of the chemical fractionation of fulvic acid (FA) that results from its association with iron and aluminum oxyhydroxide precipitates. Fractionated and unfractionated FAs obtained from streamwater and suspended sediment were utilized in acute Cu toxicity tests on ,i>Ceriodaphnia dubia. Toxicity test results with equal FA concentrations (6 mg FA/L) show that the fractionated dissolved FA was 3 times less effective at reducing Cu toxicity (EC50 13 ± 0.6 μg Cu/L) than were the unfractionated dissolved FAs (EC50 39 ± 0.4 and 41 ± 1.2 μg Cu/L). The fractionation is a consequence of preferential sorption of molecules having strong metal-binding (more aromatic) moieties to precipitating Fe- and Al-rich oxyhydroxides, causing the remaining dissolved FA to be depleted in these functional groups. As a result, there is more bioavailable dissolved Cu in the water and hence greater potential for Cu toxicity to aquatic organisms. In predicting Cu toxicity, biotic ligand models (BLMs) take into account dissolved organic carbon (DOC) concentration; however, unless DOC characteristics are accounted for, model predictions can underestimate acute Cu toxicity for water containing fractionated dissolved FA. This may have implications for water-quality criteria in systems containing Fe- and Al-rich sediment, and in mined and mineralized areas in particular. Optical measurements, such as specific ultraviolet absorbance at 254 nm (SUVA254), show promise for use as spectral indicators of DOC chemical fractionation and inferred increased Cu toxicity.

  6. Toxicity of Vertimec® 18 EC (active ingredient abamectin) to the neotropical cladoceran Ceriodaphnia silvestrii.

    Science.gov (United States)

    Casali-Pereira, Maressa P; Daam, Michiel A; de Resende, Juliana C; Vasconcelos, Ana M; Espíndola, Evaldo L G; Botta, Clarice M R

    2015-11-01

    The aim of the present study was to evaluate the toxicity of abamectin to the neotropical cladoceran Ceriodaphnia silvestrii. To this end, acute and chronic bioassays were conducted with the commercial formulation Vertimec® 18 EC. In addition, the toxicity of water samples taken from a microcosm experiment evaluating the effects of a single application (144μga.i./L) and two applications (2×36μga.i./L) of Vertimec® 18 EC, in the presence or absence of a tadpole species (Lithobates catesbeianus), was also assessed. The acute LC50-48h for immobilization was 1.47μga.i./L and chronic NOEC-8d for survival and fertility (number of neonates per female) were 169 and 84nga.i./L, respectively. Irrespective of the presence of tadpoles, water samples from the microcosms applied with the single concentration of 144μga.i./L remained toxic until the end of the experiment, even when samples were diluted 32 times with culture medium. Water in the repeated pesticide treatment showed a similar toxic response after both applications. Toxicity of water samples from the microcosms was lower than that expected based on the generated LC50 values, which is explained by a potential reduced bioavailability of the test compound resulting from absorbance to organic material. Potential side-effects on C. silvestrii related with the use of Vertimec® 18 EC in Brazil and the suitability of this species for tropical toxicity testing are discussed. PMID:26318118

  7. Crop Classification by Polarimetric SAR

    DEFF Research Database (Denmark)

    Skriver, Henning; Svendsen, Morten Thougaard; Nielsen, Flemming;

    1999-01-01

    Polarimetric SAR-data of agricultural fields have been acquired by the Danish polarimetric L- and C-band SAR (EMISAR) during a number of missions at the Danish agricultural test site Foulum during 1995. The data are used to study the classification potential of polarimetric SAR data using the...

  8. Comparison between four and seven-day Ceriodaphnia dubia survival and reproduction test protocols using oil refinery effluent samples

    Directory of Open Access Journals (Sweden)

    Eduardo Cyrino Oliveira-Filho

    2008-02-01

    Full Text Available The aim of this study was to compare the 7-day Ceriodaphnia dubia survival and reproduction test with a 4 day test to evaluate the toxicity of oil refinery effluents. Both shown identical NOECs with three of 6 tested samples. With one of the tested samples, the 4-day NOEC was one tested-concentration lower, and with the remaining two samples, it was one tested-concentration higher than those obtained using the 7-day protocol. Then results suggested that 4 and 7-day protocols were comparable to detect toxic effects.O objetivo do presente estudo foi comparar os protocolos de sobrevivência e reprodução de Ceriodaphnia dubia com 7 e 4 dias de duração, avaliando a toxicidade de amostras de efluentes de refinaria de petróleo. Ambos os protocolos apresentaram NOECs idênticos para 3 das 6 amostras testadas. Com uma das amostras o NOEC no ensaio de 4 dias ficou numa concentração testada menor, e nas duas amostras restantes ele ficou numa concentração testada maior do que os NOECs obtidos no ensaio de 7 dias. Esses resultados sugerem que os protocolos de ensaio com 4 e 7 dias são comparáveis quanto a sensibilidade para detectar o efeito tóxico crônico de efluentes de refinaria de petróleo.

  9. Behavioural and electrophysiological lateralization in a social (Apis mellifera) but not in a non-social (Osmia cornuta) species of bee.

    Science.gov (United States)

    Anfora, Gianfranco; Frasnelli, Elisa; Maccagnani, Bettina; Rogers, Lesley J; Vallortigara, Giorgio

    2010-01-20

    Recent evidence suggests that asymmetry between the left and right sides of the brain is not limited to vertebrates but extends to invertebrates as well. We compared olfactory lateralization in two species of Hymenoptera Apoidea, the honeybee (Apis mellifera), a social species, and the mason bee (Osmia cornuta), a solitary species. Recall of the olfactory memory 1 h after training to associate an odour with a sugar reward, as revealed by the bee extending its proboscis when presented with the trained odour, was better in honeybees trained with their right than with their left antenna. No such asymmetry was observed in mason bees. Similarly, electroantennographic responses to a floral volatile compound and to an alarm pheromone component were higher in the right than in the left antenna in honeybees but not in mason bees. These findings seem to support recent game-theoretical models suggesting that population-level lateralization is more likely to have evolved in social than in non-social species. PMID:19766143

  10. Acute and chronic toxicity of uranium compounds to Ceriodaphnia-Daphnia dubia

    International Nuclear Information System (INIS)

    A study to determine the acute and chronic toxicity of uranyl nitrate, hydrogen uranyl phosphate, and uranium dioxide to the organism Ceriodaphnia dubia was conducted. The toxicity tests were conducted by two independent environmental consulting laboratories. Part of the emphasis for this determination was based on concerns expressed by SCDHEC, which was concerned that a safety factor of 100 must be applied to the previous 1986 acute toxicity result of 0.22 mg/L for Daphnia pulex, This would have resulted in the LETF release limits being based on an instream concentration of 0.0022 mg/L uranium. The NPDES Permit renewal application to SCDHEC utilized the results of this study and recommended that the LETF release limit for uranium be based an instream concentration of 0.004 mg/L uranium. This is based on the fact that the uranium releases from the M-Area LETF will be in the hydrogen uranyl phosphate form, or a uranyl phosphate complex at the pH (6--10) of the Liquid Effluent Treatment Facility effluent stream, and at the pH of the receiving stream (5.5 to 7.0). Based on the chronic toxicity of hydrogen uranyl phosphate, a lower uranium concentration limit for the Liquid Effluent Treatment Facility outfall vs. the existing NPDES permit was recommended: The current NPDES permit ''Guideline'' for uranium at outfall M-004 is 0.500 mg/L average and 1.0 mg/L maximum, at a design flowrate of 60 gpm. It was recommended that the uranium concentration at the M-004 outfall be reduced to 0.28 mg/L average, and 0.56 mg/L, maximum, and to reduce the design flowrate to 30 gpm. The 0.28 mg/L concentration will provide an instream concentration of 0.004 mg/L uranium. The 0.28 mg/L concentration at M-004 is based on the combined flows from A-014, A-015, and A-011 outfalls (since 1985) of 1840 gpm (2.65 MGD) and was the flow rate which was utilized in the 1988 NPDES permit renewal application

  11. Bats and SARS

    Centers for Disease Control (CDC) Podcasts

    2006-11-08

    Bats are a natural reservoir for emerging viruses, among them henipaviruses and rabies virus variants. Dr. Nina Marano, Chief, Geographic Medicine and Health Promotion Branch, Division of Global Migration and Quarantine, CDC, explains connection between horseshoe bats and SARS coronavirus transmission.  Created: 11/8/2006 by Emerging Infectious Diseases.   Date Released: 11/17/2006.

  12. Multichannel FMCW SAR

    NARCIS (Netherlands)

    Rossum, W.L. van; Otten, M.P.G.; Dorp, Ph. van

    2012-01-01

    A light weight SAR, suitable for use on short range tactical UAV, has been designed and built. The system consists of a fully digital receive array, and a very compact active transmit antenna. The approximate weight of the complete system is 6 kg, with power consumption below 75 W, depending on the

  13. Understanding SARS with Wolfram Approach

    Institute of Scientific and Technical Information of China (English)

    Da-WeiLI; Yu-XiPAN; YunDUAN; Zhen-DeHUNG; Ming-QingXU; LinHE

    2004-01-01

    Stepping acquired immunodeficiency syndrome (AIDS), severe acute respiratory syndrome (SARS) as another type of disease has been threatening mankind since late last year. Many scientists worldwide are making great efforts to study the etiology of this disease with different approaches. 13 species of SARS virus have been sequenced. However, most people still largely rely on the traditional methods with some disadvantages. In this work, we used Wolfram approach to study the relationship among SARS viruses and between SARS viruses and other types of viruses, the effect of variations on the whole genome and the advantages in the analysis of SARS based on this novel approach. As a result, the similarities between SARS viruses and other coronaviruses are not really higher than those between SARS viruses and non-coronaviruses.

  14. Bistatic SAR: Proof of Concept.

    Energy Technology Data Exchange (ETDEWEB)

    Yocky, David A.; Doren, Neall E.; Bacon, Terry A.; Wahl, Daniel E.; Eichel, Paul H.; Jakowatz, Charles V,; Delaplain, Gilbert G.; Dubbert, Dale F.; Tise, Bertice L.; White, Kyle R.

    2014-10-01

    Typical synthetic aperture RADAR (SAR) imaging employs a co-located RADAR transmitter and receiver. Bistatic SAR imaging separates the transmitter and receiver locations. A bistatic SAR configuration allows for the transmitter and receiver(s) to be in a variety of geometric alignments. Sandia National Laboratories (SNL) / New Mexico proposed the deployment of a ground-based RADAR receiver. This RADAR receiver was coupled with the capability of digitizing and recording the signal collected. SNL proposed the possibility of creating an image of targets the illuminating SAR observes. This document describes the developed hardware, software, bistatic SAR configuration, and its deployment to test the concept of a ground-based bistatic SAR. In the proof-of-concept experiments herein, the RADAR transmitter will be a commercial SAR satellite and the RADAR receiver will be deployed at ground level, observing and capturing RADAR ground/targets illuminated by the satellite system.

  15. EARSEC SAR processing system

    Science.gov (United States)

    Protheroe, Mark; Sloggett, David R.; Sieber, Alois J.

    1994-12-01

    Traditionally, the production of high quality Synthetic Aperture Radar imagery has been an area where a potential user would have to expend large amounts of money in either the bespoke development of a processing chain dedicated to his requirements or in the purchase of a dedicated hardware platform adapted using accelerator boards and enhanced memory management. Whichever option the user adopted there were limitations based on the desire for a realistic throughput in data load and time. The user had a choice, made early in the purchase, for either a system that adopted innovative algorithmic manipulation, to limit the processing time of the purchase of expensive hardware. The former limits the quality of the product, while the latter excludes the user from any visibility into the processing chain. Clearly there was a need for a SAR processing architecture that gave the user a choice into the methodology to be adopted for a particular processing sequence, allowing him to decide on either a quick (lower quality) product or a detailed slower (high quality) product, without having to change the algorithmic base of his processor or the hardware platform. The European Commission, through the Advanced Techniques unit of the Joint Research Centre (JRC) Institute for Remote Sensing at Ispra in Italy, realizing the limitations on current processing abilities, initiated its own program to build airborne SAR and Electro-Optical (EO) sensor systems. This program is called the European Airborne Remote Sensing Capabilities (EARSEC) program. This paper describes the processing system developed for the airborne SAR sensor system. The paper considers the requirements for the system and the design of the EARSEC Airborne SAR Processing System. It highlights the development of an open SAR processing architecture where users have full access to intermediate products that arise from each of the major processing stages. It also describes the main processing stages in the overall

  16. Bistatic sAR data processing algorithms

    CERN Document Server

    Qiu, Xiaolan; Hu, Donghui

    2013-01-01

    Synthetic Aperture Radar (SAR) is critical for remote sensing. It works day and night, in good weather or bad. Bistatic SAR is a new kind of SAR system, where the transmitter and receiver are placed on two separate platforms. Bistatic SAR is one of the most important trends in SAR development, as the technology renders SAR more flexible and safer when used in military environments. Imaging is one of the most difficult and important aspects of bistatic SAR data processing. Although traditional SAR signal processing is fully developed, bistatic SAR has a more complex system structure, so sign

  17. F/H Area ETF effluent (H-016 outfall) Ceriodaphnia survival/reproduction test, test date: December 12, 1990

    International Nuclear Information System (INIS)

    This toxicity test was conducted to determine if the effluent from the F/H area of Savannah River Plant, affects the survival or reproduction of the test organisms during a seven day period. The test involved exposing the text organisms ceriodaphnia, to a series of dilutions of the effluent. At each dilution the survival and reproduction of ten test organisms was recorded. Each effluent dilution was compared to a control set of test organisms. Survival data were analyzed by Fisher's Exact Test and the Trimmed Spearman-Karber method to determine the effluent concentration necessary to cause statistically significant (p=0.05) mortality. Reproduction data was analyzed for normality, homogeneity of variance and equality of replicates among dilutions to determine appropriate statistical test for analysis of statistical differences in reproduction among dilutions. Results are summarized

  18. TerraSAR-X

    Directory of Open Access Journals (Sweden)

    Fabrizio Bernardini

    2007-03-01

    Full Text Available TerraSAR-X è sviluppato ed operato dall’Agenzia Spaziale Tedesca (DLR, Deutsches Zentrum für Luft- und Raumfahrt e da EADS Astrium con l’obiettivo di essere il primo satellite per osservazione della Terra (EO in grado di fornire globalmente e con continuità dati radar in banda X. La tecnologia Radar ad Apertura Sintetica (SAR realizzata in banda X, cioè a frequenze superiori rispetto a quelle delle bande C ed L usate in precedenza in altre missioni, permetterà di fornire servizi con risoluzioni variabili tra 1 e 16 metri.

  19. SAR based adaptive GMTI

    Science.gov (United States)

    Vu, Duc; Guo, Bin; Xu, Luzhou; Li, Jian

    2010-04-01

    We consider ground moving target indication (GMTI) and target velocity estimation based on multi-channel synthetic aperture radar (SAR) images. Via forming velocity versus cross-range images, we show that small moving targets can be detected even in the presence of strong stationary ground clutter. Moreover, the velocities of the moving targets can be estimated, and the misplaced moving targets can be placed back to their original locations based on the estimated velocities. Adaptive beamforming techniques, including Capon and generalizedlikelihood ratio test (GLRT), are used to form velocity versus cross-range images for each range bin of interest. The velocity estimation ambiguities caused by the multi-channel array geometry are analyzed. We also demonstrate the effectiveness of our approaches using the Air Force Research Laboratory (AFRL) publicly-released Gotcha SAR based GMTI data set.

  20. Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia)

    International Nuclear Information System (INIS)

    Highlights: • Trophic transfer of alumina nanoparticles using Chlorella ellipsoides and Ceriodaphnia dubia. • Subtle alterations in the feeding behaviour of the daphnids. • Disruption the energy flow through the food chain. • Transmission electron microscopy validated the disrupted feeding behaviour. - Abstract: The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120 μg/mL (196 to 1176 μM) for 48 h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and

  1. Trophic transfer potential of aluminium oxide nanoparticles using representative primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia)

    Energy Technology Data Exchange (ETDEWEB)

    Pakrashi, Sunandan; Dalai, Swayamprava; Chandrasekaran, Natarajan; Mukherjee, Amitava, E-mail: amit.mookerjea@gmail.com

    2014-07-01

    Highlights: • Trophic transfer of alumina nanoparticles using Chlorella ellipsoides and Ceriodaphnia dubia. • Subtle alterations in the feeding behaviour of the daphnids. • Disruption the energy flow through the food chain. • Transmission electron microscopy validated the disrupted feeding behaviour. - Abstract: The transfer of nanoparticles through the food chain can lead to bioaccumulation and biomagnification resulting in a long term negative impact on the ecosystem functions. The primary objective of this study was evaluation of aluminium oxide nanoparticles transfer from primary producers to primary consumers. A simple set up consisting of a primary producer (Chlorella ellipsoides) and a primary consumer (Ceriodaphnia dubia) was used. Here, C. ellipsoides were exposed to the varying concentrations of the nanoparticles ranging from 20 to 120 μg/mL (196 to 1176 μM) for 48 h and the infested algal cells were used as the feed to C. dubia. The bioaccumulation of the nanoparticles into the daphnids was noted and the biomagnification factors were computed. The exposure was noted to cause subtle alterations in the feeding behaviour of the daphnids. This might have long term consequences in the energy flow through the food chain. The reproductive behaviour of the daphnids remained unaffected upon exposure to nanoparticle infested algal feed. Distinct observations at ultra-structural scale using transmission electron microscopy provided visual evidences for the disrupted feeding behaviour upon exposure to nanoparticle treated algae. Internalization of nanoparticle like inclusion bodies in the intracellular space of algae was also detected. The findings were further substantiated by a detailed analysis of hydrodynamic stability, bioavailability and dissolution of ions from the nanoparticles over the exposure period. Altogether, the study brings out the first of its kind of observation of trophic transfer potential/behaviour of aluminium oxide nanoparticles and

  2. Bayesian SAR imaging

    Science.gov (United States)

    Chen, Zhaofu; Tan, Xing; Xue, Ming; Li, Jian

    2010-04-01

    We introduce a maximum a posteriori (MAP) algorithm and a sparse learning via iterative minimization (SLIM) algorithm to synthetic aperture radar (SAR) imaging. Both MAP and SLIM are sparse signal recovery algorithms with excellent sidelobe suppression and high resolution properties. The former cyclically maximizes the a posteriori probability density function for a given sparsity promoting prior, while the latter cyclically minimizes a regularized least squares cost function. We show how MAP and SLIM can be adapted to the SAR imaging application and used to enhance the image quality. We evaluate the performance of MAP and SLIM using the simulated complex-valued backscattered data from a backhoe vehicle. The numerical results show that both MAP and SLIM satisfactorily suppress the sidelobes and yield higher resolution than the conventional matched filter or delay-and-sum (DAS) approach. MAP and SLIM outperform the widely used compressive sampling matching pursuit (CoSaMP) algorithm, which requires the delicate choice of user parameters. Compared with the recently developed iterative adaptive approach (IAA), MAP and SLIM are computationally more efficient, especially with the help of fast Fourier transform (FFT). Also, the a posteriori distribution given by the algorithms provides us with a basis for the analysis of the statistical properties of the SAR image pixels.

  3. Novel Polarimetric SAR Interferometry Algorithms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Polarimetric SAR interferometry (PolInSAR) is a recently developed synthetic aperture radar (SAR) imaging mode that combines the capabilities of radar polarimetry...

  4. SAR Image Processing using GPU

    Science.gov (United States)

    Shanmugha Sundaram, GA; Sujith Maddikonda, Syam

    Synthetic aperture Radar (SAR) has been extensively used for space-borne Earth observations in recent times. In conventional SAR systems analog beam-steering techniques are capable of implementing multiple operational modes, such as the Stripmap, ScanSAR, and Spotlight, to fulfill the different requirements in terms of spatial resolution and coverage. Future RADAR satellites need to resolve the complex issues such as wide area coverage and resolution. Digital beamforming (DBF) is a promising technique to overcome the problems mentioned above. In communication satellites DBF technique is already implemented. This paper discuses the relevance of DBF in space-borne RADAR satellites for enhancements to quality imaging. To implement DBF in SAR, processing of SAR data is an important step. This work focused on processing of Level 1.1 and 1.5 SAR image data. The SAR raw data is computationally intensive to process. To resolve the computation problem, high performance computing (HPC) is necessary. The relevance of HPC for SAR data processing using an off-the-shelf graphical processing unit (GPU) over CPU is discussed in this paper. Quantitative estimates on SAR image processing performance comparisons using both CPU and GPU are also provided as validation for the results.

  5. Recovering Seasat SAR Data

    Science.gov (United States)

    Logan, T. A.; Arko, S. A.; Rosen, P. A.

    2013-12-01

    To demonstrate the feasibility of orbital remote sensing for global ocean observations, NASA launched Seasat on June 27th, 1978. Being the first space borne SAR mission, Seasat produced the most detailed SAR images of Earth from space ever seen to that point in time. While much of the data collected in the USA was processed optically, a mere 150 scenes had been digitally processed by March 1980. In fact, only an estimated 3% of Seasat data was ever digitally processed. Thus, for over three decades, the majority of the SAR data from this historic mission has been dormant, virtually unavailable to scientists in the 21st century. Over the last year, researchers at the Alaska Satellite Facility (ASF) Distributed Active Archive Center (DAAC) have processed the Seasat SAR archives into imagery products. A telemetry decoding system was created and the data were filtered into readily processable signal files. Due to nearly 35 years of bit rot, the bit error rate (BER) for the ASF DAAC Seasat archives was on the order of 1 out of 100 to 1 out of 100,000. This extremely high BER initially seemed to make much of the data undecodable - because the minor frame numbers are just 7 bits and no range line numbers exist in the telemetry even the 'simple' tasks of tracking the minor frame number or locating the start of each range line proved difficult. Eventually, using 5 frame numbers in sequence and a handful of heuristics, the data were successfully decoded into full range lines. Concurrently, all metadata were stored into external files. Recovery of this metadata was also problematic, the BER making the information highly suspect and, initially at least, unusable in any sort of automated fashion. Because of the BER, all of the single bit metadata fields proved unreliable. Even fields that should be constant for a data take (e.g. receiving station, day of the year) showed high variability, each requiring a median filter to be usable. The most challenging, however, were the

  6. Demonstration MTI/SAR capability

    NARCIS (Netherlands)

    Vries, F.P.P. de; Broek, A.C. van den; Otten, M.P.G.; Groot, J.S.; Steeghs, T.P.H.; Dekker, R.J.; Rossum, W.L. van

    2001-01-01

    The aim of this project is to demonstrate to the Dutch armed forces the capability of MTI (Moving Target Indicator) and SAR (Synthetic Aperture Radar). This is done with the Dutch PHARUS sensor. The sensor is used to demonstrate how a phased array antenna can be used as an MTI/SAR sensor combination

  7. Bistatic SAR: Imagery & Image Products.

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-10-01

    While typical SAR imaging employs a co-located (monostatic) RADAR transmitter and receiver, bistatic SAR imaging separates the transmitter and receiver locations. The transmitter and receiver geometry determines if the scattered signal is back scatter, forward scatter, or side scatter. The monostatic SAR image is backscatter. Therefore, depending on the transmitter/receiver collection geometry, the captured imagery may be quite different that that sensed at the monostatic SAR. This document presents imagery and image products formed from captured signals during the validation stage of the bistatic SAR research. Image quality and image characteristics are discussed first. Then image products such as two-color multi-view (2CMV) and coherent change detection (CCD) are presented.

  8. SAR Altimetry Applications over Water

    CERN Document Server

    Martin-Puig, C; Ruffini, G; Raney, R K; Benveniste, J

    2008-01-01

    The application of Synthetic Aperture Radar (SAR) techniques to classical radar altimetry offers the potential for greatly improved Earth surface mapping. This paper provides an overview of the progress of SAMOSA, Development of SAR Altimetry Studies and Applications over Ocean, Coastal zones and Inland waters, an on-going ESA-funded project. The main objective of SAMOSA is to better quantify the improvement of SAR altimetry over conventional altimetry on water surfaces. More specifically, one of the tasks focuses on the reduction of SAR mode data to pulse-limited altimeter data, and a theoretical modelling to characterize the expected gain between high Pulse Repetition Frequency (PRF) reduced SAR mode data and low PRF classical Low-Resolution Mode (LRM) data. To this end, theoretical modelling using the Cramer-Rao bound (CRB) will be used and the results will be compared to previous theoretical estimates [7], using an analysis akin to that in [8].

  9. State-of-art of Geosynchronous SAR

    Institute of Scientific and Technical Information of China (English)

    MAO Er-ke; LONG Teng; ZENG Tao; HU Cheng; TIAN Ye

    2012-01-01

    Geosynchronous Earth Orbit Synthetic Aperture Radar (GEO SAR) runs in the height of 360000Km geosynchronous earth orbit,compared with traditional Low Earth Orbit (LEO) SAR (orbit height under 1000Km),GEO SAR has advantages of shorter repeat period,wider swath and so on.Firstly,the basic principle and state-of-art of GEO SAR in domestic and overseas are introduced.Secondly,coverage characteristic of GEO SAR is analyzed.Thirdly,the key problems of yaw steering and imaging on curved trajectory in GEO SAR are discussed in detail,and the corresponding primary solutions are presented in order to promote future research on GEO SAR.

  10. SAR/InSAR observation by an HF sounder

    Science.gov (United States)

    Kobayashi, T.; Ono, T.

    2007-03-01

    Application of SAR imaging algorithm to spaceborne HF sounder observation was studied. Two types of image ambiguity problems were addressed in the application. One is surface/subsurface image ambiguity arising from deep penetration of HF wave, and another is mirror image ambiguity that is inherent to dipole antenna SAR. A numerical model demonstrated that the surface/subsurface ambiguity can be mitigated by taking a synthetic aperture large enough to defocus subsurface objects. In order to resolve the mirror image ambiguity problem, an image superposition technique was proposed. The performance of the technique was demonstrated by using simulation data of the HF sounder observation to confirm the feasibility of HF SAR and HF InSAR observation.

  11. DEM FROM SAR:PRINCIPLE AND APPLICATION

    Institute of Scientific and Technical Information of China (English)

    Li Deren; Yang Jie

    2003-01-01

    The paper gives an overview of the principle and application of generating DEM from SAR, including the principle and processing flow of generating DEM from single SAR and SAR interferometry. Afterwards, the application fields of InSAR for terrain surveying, volcanic terrain surveying and D-InSAR for monitoring ground subsiding are listed and described as well.The problem and prospect of application are also pointed out in the last part of this paper.

  12. Influence of glyphosate and its formulation (Roundup[reg]) on the toxicity and bioavailability of metals to Ceriodaphnia dubia

    International Nuclear Information System (INIS)

    This study examined the toxicological interaction between glyphosate (or its formulation, Roundup[reg]) and several heavy metals to a freshwater cladoceran, Ceriodaphnia dubia. We demonstrated that all binary combinations of Roundup[reg] and metals (Cd, Cu, Cr, Ni, Pb, Se and Zn) exhibited 'less than additive' mixture toxicity, with 48-h LC50 toxic unit>1. Addition of glyphosate alone could significantly reduce the acute toxicity of Ag, Cd, Cr, Cu, Ni, Pb and Zn (but not Hg and Se). The ratio between glyphosate and metal ions was important in determining the mitigation of metal toxicity by glyphosate. A bioaccumulation study showed that in the presence of glyphosate the uptake of some metals (e.g. Ag) was halted but that of others (e.g. Hg) was increased significantly. Therefore, our study strongly suggests that glyphosate and its commercial formulations can control the toxicity as well as the bioavailability of heavy metals in aquatic ecosystems where both groups of chemicals can co-occur. - Glyphosate can control the toxicity and bioavailability of many heavy metals in the aquatic environment

  13. TerraSAR-X mission

    Science.gov (United States)

    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

  14. Statistical Unmixing of SAR Images

    OpenAIRE

    Anfinsen, Stian Normann

    2016-01-01

    A method is presented which uses logarithmic statistics to detect and characterise class mixtures and targets in background clutter in synthetic aperture radar (SAR) images. Mixtures of ground cover types show up as extreme radar texture in statistical analysis of SAR images. Instead of modelling this as a spatially nonstationary radar cross section, this paper demonstrates how a mixture model analysis can be used to characterise the separate components and estimate their mixing proportions.

  15. 角石蕊中松萝酸的提取工艺及含量测定%Extraction technology of usnic acid from Cladonia cornuta(L.)Hoffm and content determination

    Institute of Scientific and Technical Information of China (English)

    热衣木·马木提; 阿地里江; 阿不都拉·阿巴斯

    2010-01-01

    以新疆天山后峡地区英雄桥采集的角石蕊(Cladonia cornuta(L.)Hoffm.)为材料,采用有机溶剂提取法,考察了提取次数、料液比、提取温度和提取时间对角石蕊中松萝酸提取率的影响.试验结果表明:角石蕊中提取松萝酸的最佳提取工艺条件为提取3次,料液比1:20,温度70℃,提取时间3h.此条件下角石蕊中松萝酸的含最为26.95%.

  16. Toxic effects of Pseudanabaena tenuis (Cyanobacteria on the cladocerans Daphnia magna and Ceriodaphnia dubia Efectos tóxicos de Pseudanabaena tenuis (Cyanobacteria en los cladóceros Daphnia magna y Ceriodaphnia dubia

    Directory of Open Access Journals (Sweden)

    Roxana Olvera-Ramírez

    2010-01-01

    Full Text Available Some cyanobacteria can produce toxins that affect the aquatic biota and represent a human health risk. The cyanobacterium Pseudanabaena tenuis was isolated from the Valle de Bravo dam, and cultured in the laboratory under controlled conditions. We determined the acute toxic effects and performed a chronic (consumption test in the cladocerans Daphnia magna (a reference test organism and Ceriodaphnia dubia (a cosmopolitan species. To determine acute toxicity, three exposure ways were assayed: a cell-free culture medium, b crude cell extracts of the cyanobacterium after lysing, and c aqueous extracts of P. tenuis phycobiliproteins. On the other hand, both cladocerans were fed P. tenuis, assessing the effects on survival and reproduction. For comparison, a control culture of both cladocerans was fed the green microalga Pseudokirchneriella subcapitata. Exposure to the cell-free culture medium did not produce any mortality in either cladoceran, but the aqueous and crude extracts generated acute toxicity. D. magna and C. dubia were negatively affected when fed P. tenuis, since their survival, total progeny, average number of neonates per clutch, and the number of clutches decreased. C. dubia was more sensitive than D. magna, both in the acute toxicity tests and to the effects of P. tenuis consumption. Although most of the blooms around the world are dominated by cyanobacteria of the genus Microcystis, attention should be given to other species, such as P. tenuis, because, frequently, it is not recognized that smaller cyanobacteria could exceed the larger species in terms of biomass, and produce noxious biological effects.Algunas cianobacterias producen toxinas que afectan la biota acuática y representan un riesgo para la salud humana. La cianobacteria Pseudanabaena tenuis fue aislada del embalse Valle de Bravo y cultivada en el laboratorio. Se determinaron los efectos tóxicos agudos (por exposición y se evaluó la toxicidad crónica (por consumo

  17. Toxicity of waters from the Rochester Embayment Area of Concern to the plankton species Pseudokirchneriella subcapitata and Ceriodaphnia dubia

    Science.gov (United States)

    Baldigo, Barry P.; Duffy, Brian T.; Smith, Alexander J; George, Scott D.

    2016-01-01

    The lower Genesee River and Rochester Embayment of Lake Ontario are a designated Area of Concern (AOC) under the binational Great Lakes Water Quality Agreement. The “degradation of phytoplankton and zooplankton populations” or plankton Beneficial Use Impairment (BUI) was classified as unknown and in need of further assessment in this AOC because water quality data suggested plankton communities could be effected and community data were either unavailable or indicated impacts. The plankton BUI may now be obsolete because local contaminant sources have been largely eliminated. The present study was conducted between July 2013 and August 2014 to assess the BUI-removal criteria: “AOC plankton bioassays confirm that toxicity in ambient waters (i.e., no growth inhibition) is not significantly higher than comparable non-AOC controls”. Acute and chronic toxicity of waters from 13 sites were quantified seasonally using standardized bioassays with the green alga Pseudokirchneriella subcapitata and water flea Ceriodaphnia dubia to test the hypothesis that toxicity of waters from AOC sites was not higher than that of waters from comparable non-AOC reference sites. Survival and reproduction of C. dubia did not differ significantly between site types, systems, or months. The growth of P. subcapitata did not differ between site types, but differed among systems and months. All results indicate that waters from AOC sites were no more toxic to both plankton species than waters from reference sites. Assuming test species represent natural plankton assemblages, water quality should not negatively affect survival and growth of resident plankton populations in the Rochester Embayment AOC.

  18. SARS Patients and Their Close Contacts

    Science.gov (United States)

    ... Laboratory Testing & Specimens SARS-Associated Coronavirus (SARS-CoV) Sequencing Informed Consent for Laboratory Testing Specimen Collection and ... person touches a surface or object contaminated with infectious droplets and then touches his or her mouth, ...

  19. Novel Polarimetric SAR Interferometry Algorithms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Polarimetric radar interferometry (PolInSAR) is a new SAR imaging mode that is rapidly becoming an important technique for bare earth topographic mapping, tree...

  20. SAR Image Enhancement using Particle Filters

    Data.gov (United States)

    National Aeronautics and Space Administration — In this paper, we propose a novel approach to reduce the noise in Synthetic Aperture Radar (SAR) images using particle filters. Interpretation of SAR images is a...

  1. New pathogenic mechanism of SARS virus

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ The outbreak of the severe acute respiratory syndrome (SARS) in 2002 caused alarm across the world. A coronavirus in humans, called SARS-CoV, has been identified as the causative agent for this killer disease.

  2. Accelerated Scientific InSAR Processing Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Neva Ridge Technologies proposes to develop a suite of software tools for the analysis of SAR and InSAR data, focused on having a robust and adopted capability well...

  3. Urban Change Detection Using Multitemporal SAR Images

    OpenAIRE

    Yousif, Osama

    2015-01-01

    Multitemporal SAR images have been increasingly used for the detection of different types of environmental changes. The detection of urban changes using SAR images is complicated due to the complex mixture of the urban environment and the special characteristics of SAR images, for example, the existence of speckle. This thesis investigates urban change detection using multitemporal SAR images with the following specific objectives: (1) to investigate unsupervised change detection, (2) to inve...

  4. Change Detection Using Multitemporal SAR Images

    OpenAIRE

    Yousif, Osama

    2013-01-01

    Multitemporal SAR images have been used successfully for the detection of different types of environmental changes. The detection of urban change using SAR images is complicated due to the special characteristics of SAR images—for example, the existence of speckle and the complex mixture of the urban environment. This thesis investigates the detection of urban changes using SAR images with the following specific objectives: (1) to investigate unsupervised change detection, (2) to investigate ...

  5. SARS Vaccine: Progress and Challenge

    Institute of Scientific and Technical Information of China (English)

    Yan Zhi; James M. Wilson; Hao Shen

    2005-01-01

    Severe acute respiratory syndrome (SARS) emerged in 2002 as a severe and highly contagious infectious disease that rapidly spread to a number of different countries. The collaborative efforts of the global scientific community have provided, within a short period of time, substantial insights into the molecular biology and immunology of SARS-CoV. Although the outbreak has been contained, there is continuous concern that the virus may resurface into the human population through seasonal changes, animal reservoirs or laboratory accidents. The severe morbidity and mortality associated with SARS make it imperative that an effective vaccine be developed to prevent reemergence and epidemics in the future. Cellular & Molecular Immunology. 2005;2(2):101-105.

  6. SARS Vaccine: Progress and Challenge

    Institute of Scientific and Technical Information of China (English)

    YanZhi; JamesM.Wilson; HaoShen

    2005-01-01

    Severe acute respiratory syndrome (SARS) emerged in 2002 as a severe and highly contagious infectious disease that rapidly spread to a number of different countries. The collaborative efforts of the global scientific community have provided, within a short period of time, substantial insights into the molecular biology and immunology of SARS-CoV. Although the outbreak has been contained, there is continuous concern that the virus may resurface into the human population through seasonal changes, animal reservoirs or laboratory accidents. The severe morbidity and mortality associated with SARS make it imperative that an effective vaccine be developed to prevent reemergence and epidemics in the future. Cellular & Molecular Immunology. 2005;2(2):101-105.

  7. Convolutional Neural Networks for SAR Image Segmentation

    DEFF Research Database (Denmark)

    Malmgren-Hansen, David; Nobel-Jørgensen, Morten

    2015-01-01

    Segmentation of Synthetic Aperture Radar (SAR) images has several uses, but it is a difficult task due to a number of properties related to SAR images. In this article we show how Convolutional Neural Networks (CNNs) can easily be trained for SAR image segmentation with good results. Besides...

  8. CFAR Edge Detector for Polarimetric SAR Images

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning; Nielsen, Allan Aasbjerg;

    2003-01-01

    SAR data. By simply changing the parameters characterizing the test statistic according to the applied SAR data, constant false-alarm rate detection is always obtained. An adaptive filtering scheme is presented, and the distributions of the detector are verified using simulated polarimetric SAR images...

  9. Realtime processor of SAR systems

    Science.gov (United States)

    Schotter, R.

    Attention is given to potential applications of a synthetic aperture radar (SAR) real time processor which was developed for Space Shuttle-based earth sensing, and which may prove useful in military surveillance, ocean wave studies, ship movements in territorial waters, land conservation, geology, and mineralogical prospecting. The SAR processor's signal processing task is characterized by complex algorithms and large quantities of raw data/time unit. A 'pipeline' configuration has been judged optimal for this type of processing, and it will consist of digital hardware modules for Fourier transform, digital filtering, two-dimensional image memory, and complex multiplication.

  10. Polarimetric scattering and SAR information retrieval

    CERN Document Server

    Jin, Ya-Qiu

    2013-01-01

    Taking an innovative look at Synthetic Aperture Radar (SAR), this practical reference fully covers new developments in SAR and its various methodologies and enables readers to interpret SAR imagery An essential reference on polarimetric Synthetic Aperture Radar (SAR), this book uses scattering theory and radiative transfer theory as a basis for its treatment of topics. It is organized to include theoretical scattering models and SAR data analysis techniques, and presents cutting-edge research on theoretical modelling of terrain surface. The book includes quantitative app

  11. Stalking SARS: CDC at Work

    Centers for Disease Control (CDC) Podcasts

    2014-05-22

    In this podcast for kids, the Kidtastics talk about the SARS outbreak and how CDC worked to solve the mystery.  Created: 5/22/2014 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 5/22/2014.

  12. Reflectors for SAR performance testing.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2008-01-01

    Synthetic Aperture Radar (SAR) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.

  13. SAR Image Complex Pixel Representations

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    Complex pixel values for Synthetic Aperture Radar (SAR) images of uniform distributed clutter can be represented as either real/imaginary (also known as I/Q) values, or as Magnitude/Phase values. Generally, these component values are integers with limited number of bits. For clutter energy well below full-scale, Magnitude/Phase offers lower quantization noise than I/Q representation. Further improvement can be had with companding of the Magnitude value.

  14. Signal Processing for Digital Beamforming FMCW SAR

    Directory of Open Access Journals (Sweden)

    Qin Xin

    2014-01-01

    Full Text Available According to the limitations of single channel Frequency Modulation Continuous Wave (FMCW Synthetic Aperture Radar (SAR, Digital Beamforming (DBF technology is introduced to improve system performance. Combined with multiple receive apertures, DBF FMCW SAR can obtain high resolution in low pulse repetition frequency, which can increase the processing gain and decrease the sampling frequency. The received signal model of DBF FMCW SAR is derived. The continuous antenna motion which is the main characteristic of FMCW SAR received signal is taken into account in the whole signal processing. The detailed imaging diagram of DBF FMCW SAR is given. A reference system is also demonstrated in the paper by comparing with a single channel FMCW SAR. The validity of the presented diagram is demonstrated with a point target simulation results.

  15. INSTANTANEOUS DOPPLER FREQUENCY FOR SQUINT SAR IMAGING

    Institute of Scientific and Technical Information of China (English)

    Liu Guangyan; Huang Shunji

    2003-01-01

    Instantaneous Doppler frequency for squint SAR imaging has been found with ChirpScaling Algorithm (CSA). Because the azimuth sample is not perpendicular to the range sample,the range signal must impact on the azimuth signal in the squint SAR data processing, andthe different slant range targets have different Doppler frequencies. From the mathematicalmodel of SAR echo signal, this paper carefully analyzes the instantaneous azimuth frequency, theinstantaneous Doppler frequency component of the azimuth frequency and the impact of rangechirp on azimuth frequency, which explains that Doppler frequency should be properly selected forcorrect SAR imaging in the squint SAR. The results of point target simulation experiments showthat the way is reasonable for the squint SAR and can effectively complete range compressionand azimuth focusing, and improve images' quality.

  16. Segmentation Technique of SAR Imagery using Entropy

    Directory of Open Access Journals (Sweden)

    Debabrata Samanta

    2011-09-01

    Full Text Available SAR Image Segmentation plays an important role in image of SAR plays an important role in image analysis and computer vision .The good performance of recognition algorithms depend on the quality of segmented image. An importantproblem in SAR image application is correct segmentation.It is the basis of the understanding of SAR images,such as the chnge detection of regions for maps updating and classify the land, forest, hills, oceans etc. The ability of SAR image is to penetrate cloud cover to predict the weather condition at any particular instant of time.This paper presents a novel algorithm for SAR images segmentation based on entropy based and RGB color intensity together. Since entropy is a statistical measure of randomness that can be used to characterize the texture of the input image.

  17. Spaceborne SAR Imaging Algorithm for Coherence Optimized.

    Directory of Open Access Journals (Sweden)

    Zhiwei Qiu

    Full Text Available This paper proposes SAR imaging algorithm with largest coherence based on the existing SAR imaging algorithm. The basic idea of SAR imaging algorithm in imaging processing is that output signal can have maximum signal-to-noise ratio (SNR by using the optimal imaging parameters. Traditional imaging algorithm can acquire the best focusing effect, but would bring the decoherence phenomenon in subsequent interference process. Algorithm proposed in this paper is that SAR echo adopts consistent imaging parameters in focusing processing. Although the SNR of the output signal is reduced slightly, their coherence is ensured greatly, and finally the interferogram with high quality is obtained. In this paper, two scenes of Envisat ASAR data in Zhangbei are employed to conduct experiment for this algorithm. Compared with the interferogram from the traditional algorithm, the results show that this algorithm is more suitable for SAR interferometry (InSAR research and application.

  18. Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) pilot study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Simbeck, D.J.

    1993-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a pilot study during the week of April 22--29, 1993, prior to initiation of CR-ERP Phase 2 Sampling and Analysis activities. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field Engineering personnel from Clinch River Mile 9.0 and Poplar Creek Kilometer 1.6 on April 21, 23, and 26. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival, growth, or reproduction) to either species in testing conducted by TVA. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Reference toxicant test information; and Personnel training documentation.

  19. Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Russell, C.L.

    1993-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of July 22--29, 1993. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected by TVA Field engineering personnel from Clinch River Mile 19.0 and Mile 22.0 on July 21, 23, and 26. Samples were split and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival, growth, or reproduction) to either species in testing conducted by TVA. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; and Reference toxicant test information.

  20. Immunofluorescence Assay for Serologic Diagnosis of SARS

    OpenAIRE

    Chan, Paul K. S.; Ng, King-Cheung; Chan, Rickjason C. W.; Lam, Rebecca K. Y.; Chow, Viola C. Y.; Hui, Mamie; Wu, Alan; Lee, Nelson; Yap, Florence H.Y.; Cheng, Frankie W.T.; Joseph J. Y. Sung; Tam, John S

    2004-01-01

    We evaluated a virus-infected cell-based indirect immunofluorescence assay for detecting anti–severe acute respiratory syndrome-associated coronavirus (SARS-CoV) immunoglobulin (Ig) G antibody. All confirmed SARS cases demonstrated seroconversion or fourfold rise in IgG antibody titer; no control was positive. Sensitivity and specificity of this assay were both 100%. Immunofluorescence assay can ascertain the status of SARS-CoV infection.

  1. Sparse Reconstruction techniques for Tomographic SAR Inversion

    OpenAIRE

    Zhu, Xiao Xiang; Bamler, Richard

    2013-01-01

    Tomographic SAR inversion is essentially a spectral analysis problem. The resolution in the elevation direction depends on the spread of orbit tracks. Since the orbits of modern meter-resolution space-borne SAR systems, such as TerraSAR-X, are tightly controlled, the tomographic elevation resolution is at least an order of magnitude lower than in range and azimuth. Hence, super-resolution reconstruction algorithms are desired. Considering the sparsity of the signal in elevation, here the theo...

  2. Signal Processing for Digital Beamforming FMCW SAR

    OpenAIRE

    Qin Xin; Zhihong Jiang; Pu Cheng; Mi He

    2014-01-01

    According to the limitations of single channel Frequency Modulation Continuous Wave (FMCW) Synthetic Aperture Radar (SAR), Digital Beamforming (DBF) technology is introduced to improve system performance. Combined with multiple receive apertures, DBF FMCW SAR can obtain high resolution in low pulse repetition frequency, which can increase the processing gain and decrease the sampling frequency. The received signal model of DBF FMCW SAR is derived. The continuous antenna motion which is the ma...

  3. MIMO-SAR: Opportunities and Pitfalls

    OpenAIRE

    Krieger, Gerhard

    2014-01-01

    This paper reviews advanced radar architectures that employ multiple transmit and multiple receive antennas to improve the performance of future synthetic aperture radar (SAR) systems. These advanced architectures have been dubbed multiple-input multiple-output SAR (MIMO-SAR) in analogy to MIMO communication systems. Considerable confusion arose, however, with regard to the selection of suitable waveforms for the simultaneous transmission via multiple channels. It is shown that the mere use o...

  4. MIMO-SAR and the Orthogonality Confusion

    OpenAIRE

    Krieger, Gerhard; Younis, Marwan; Huber, Sigurd; Bordoni, Federica; Patyuchenko, Anton; Kim, Junghyo; Laskowski, Piotr; Villano, Michealangelo; Rommel, Tobias; Lopez-dekker, Paco; Moreira, Alberto

    2012-01-01

    This paper reviews radar architectures that employ multiple transmit and multiple receive channels to improve the performance of synthetic aperture radar (SAR) systems. These advanced architectures have been dubbed multiple-input multiple-output SAR (MIMO-SAR) in analogy to MIMO communication systems. Considerable confusion arose, however, with regard to the selection of suitable waveforms for the simultaneous transmission via multiple antennas. In this paper, it is shown that the mere use of...

  5. MiniSAR: a miniature, lightweight, low cost, scalable SAR system

    NARCIS (Netherlands)

    Steeghs, T.P.H.; Halsema, D. van; Hoogeboom, P.

    2001-01-01

    TNO-FEL is developing a miniature, lightweight, low cost, and scalable SAR/MTI system called 'MiniSAR'. The MiniSAR system will be unique in its size and architecture. Initially the demonstrator system will be integrated in a two-seater motorglider platform. Wherever possible, commercial-off-the-she

  6. DETEKCIJA SPREMEMB V RADARSKIH SLIKAH SAR

    OpenAIRE

    Izak, Rok

    2016-01-01

    V magistrskem delu je opisan princip detekcije sprememb površja Zemlje s pomočjo radarskih slik SAR, ki so bile zajete s satelitom TanDEM-X. Opisani so tudi principi delovanja radarja z umetno odprtino, načini zajema podatkov ter osnove interferometrije V prvem sklopu magistrskega dela, je bil cilj predlagati metodo za zaznavo gozdne površine v slikah SAR. V drugem delu so bile s pomočjo SAR interferometrije zaznane spremembe na kroni gozdov v okolici Postojne. Slike SAR, so bile zajete v raz...

  7. Bistatic SAR: Signal Processing and Image Formation.

    Energy Technology Data Exchange (ETDEWEB)

    Wahl, Daniel E.; Yocky, David A.

    2014-10-01

    This report describes the significant processing steps that were used to take the raw recorded digitized signals from the bistatic synthetic aperture RADAR (SAR) hardware built for the NCNS Bistatic SAR project to a final bistatic SAR image. In general, the process steps herein are applicable to bistatic SAR signals that include the direct-path signal and the reflected signal. The steps include preprocessing steps, data extraction to for a phase history, and finally, image format. Various plots and values will be shown at most steps to illustrate the processing for a bistatic COSMO SkyMed collection gathered on June 10, 2013 on Kirtland Air Force Base, New Mexico.

  8. InfoTerra/TerraSAR initiative

    Science.gov (United States)

    Wahl, Manfred W.

    2004-01-01

    The overarching goal of the InfoTerra/TerraSAR Initiative is to establish a self-sustaining operational/commercial business built on Europe"s know-how and experience in space-borne Synthetic Aperture Radar (SAR) technology, in SAR data processing as well as in SAR applications. InfoTerra stands for a new business concept based on supplying innovative geo-information products and services. TerraSAR is a space and ground system conceived to consist of an initial deployment and operation of 2 Radar satellites (one in X- and one in L-band) flying in a tandem configuration in the same orbit. The design of TerraSAR is driven by the market and is user-oriented. TerraSAR is key to capturing a significant proportion of the existing market and to opening new market opportunities, when it becomes operational. The InfoTerra/TerraSAR Initiative has evolved gradually. It started in 1997 as a joint venture between German (DSS) and British (MMS-UK) space industry, strongly supported by both space agencies, DLR and BNSC. In early 2001, DLR and BNSC submitted to ESA the Formal Programme Proposal for InfoTerra/TerraSAR to become an essential element of ESA"s Earth Watch Programme. In summer 2001, when it became evident that there was not yet sufficient support from the ESA Member States to allow immediate start entering into TerraSAR Phase C/D, it has been decided to implement first a TerraSAR consolidation phase. In early 2002, in order to avoid further delays, a contract was signed between DLR and Astrium GmbH on the development of one component of TerraSAR, the TerraSAR-X, in the frame of a national programme, governed by a Public Private Partnership Agreement. Even if now the different launch dates for TerraSAR-X and TerraSAR-L are narrowing down the window of common data acquisition, it is a reasonable starting point, but it should always be kept in mind that the utmost goal for the longterm is to achieve self sustainability by supplying geo-information products and services

  9. ESI -MS characterization and rapid identification of three types of triterpenoid saponins in Ilex cornuta%枸骨叶中3类三萜皂苷类成分的ESI - MS裂解规律及其快速识别

    Institute of Scientific and Technical Information of China (English)

    张加余; 姚志容; 张凡; 屠鹏飞

    2012-01-01

    Objective: To investigate the ESI - MS characterization and rapid identification of three types of triterpenoid saponins with different parent nucleuses in Ilex cornuta. Methods; HPLC - ESI - MS method was used to investigate the ESI -MS( + ) characteristics of those triterpenoid saponins, which were adopted to indentify three types of triterpenoid saponins in Ilex cornuta. Results; Three types of triterpenoid saponins have different ESI - MS ( + ) characteristics, by which 29 triterpenoid saponins were rapidly identified from the extract of Ilex cornuta. A-mong them, 10 compounds were accurately identified by comparison with reference substances. Conclusions;HPLC -ESI - MS has been provided not only as a new thread and method for rapidly identification of triterpenoid saponins from complex system, but also an effective method for target separation of constituents in natural drugs.%目的:研究枸骨叶中3类不同母核结构的三萜皂苷的ESI - MS裂解规律及其快速识别方法.方法:采用HPLC - ESI -MS技术研究3类三萜皂苷单体的ESI - MS(+)裂解规律,并采用该方法对药材中所含的3类成分进行快速识别.结果:3类三萜皂苷具有不同的ESI - MS(+)裂解特征;利用这些特征从枸骨叶提取物中快速筛选了29个三萜皂苷,其中10个可通过与对照品比对被准确鉴定.结论:利用HPLC - ESI - MS技术可以从复杂体系中快速筛选三萜皂苷类成分,为有目标的天然产物分离提供有效的方法.

  10. Sentinel-3 SAR Altimetry Toolbox

    Science.gov (United States)

    Benveniste, Jerome; Lucas, Bruno; DInardo, Salvatore

    2015-04-01

    The prime objective of the SEOM (Scientific Exploitation of Operational Missions) element is to federate, support and expand the large international research community that the ERS, ENVISAT and the Envelope programmes have build up over the last 20 years for the future European operational Earth Observation missions, the Sentinels. Sentinel-3 builds directly on a proven heritage of ERS-2 and Envisat, and CryoSat-2, with a dual-frequency (Ku and C band) advanced Synthetic Aperture Radar Altimeter (SRAL) that provides measurements at a resolution of ~300m in SAR mode along track. Sentinel-3 will provide exact measurements of sea-surface height along with accurate topography measurements over sea ice, ice sheets, rivers and lakes. The first of the two Sentinels is expected to be launched in early 2015. The current universal altimetry toolbox is BRAT (Basic Radar Altimetry Toolbox) which can read all previous and current altimetry mission's data, but it does not have the capabilities to read the upcoming Sentinel-3 L1 and L2 products. ESA will endeavour 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

  11. Spaceborne Reflector SAR Systems with Digital Beamforming

    OpenAIRE

    Huber, Sigurd; Younis, Marwan; Krieger, Gerhard; Patyuchenko, Anton; Moreira, Alberto

    2012-01-01

    Spaceborne Synthetic Aperture Radar (SAR) imaging enters an era where increasingly short revisit times, or large swath widths, respectively, and high spatial resolutions are requested. These requirements impose contradicting constraints on conventional SAR systems using analog beamforming technology. The development for future radar satellites is therefore towards digital beamforming (DBF) systems where the analogous receiver hardware is replaced by digital components. Co...

  12. History of SAR at Lockheed Martin (previously Goodyear Aerospace)

    Science.gov (United States)

    Lasswell, Stephen W.

    2005-05-01

    Synthetic Aperture Radar (SAR) was invented by Carl Wiley at Goodyear Aircraft Company in Goodyear, Arizona, in 1951. From that time forward, as the company became Goodyear Aerospace Corporation, Loral Corporation, and finally Lockheed Martin Corporation, the Arizona employees past and present played a long and storied role in numerous SAR firsts. These include the original SAR patent (known as Simultaneous Doppler Buildup), the first demonstration SAR and flight test, the first operational SAR system, the first operational SAR data link, the first 5-foot resolution operational SAR system, the first 1-foot resolution SAR system, and the first large scale SAR digital processor. The company has installed and flown over five hundred SAR systems on more than thirty different types of aircraft for numerous countries throughout the world. The company designed and produced all of the evolving high performance SAR systems for the U. S. Air Force SR-71 "Blackbird" spy plane throughout its entire operational history, spanning some twenty-nine years. Recent SAR accomplishments include long-range standoff high performance SAR systems, smaller high resolution podded SAR systems for fighter aircraft, and foliage penetration (FOPEN) SAR. The company is currently developing the high performance SAR/MTI (Moving Target Indication) radar for the Army Aerial Common Sensor (ACS) system.

  13. Updated progress in theories and applications of spaceborne SAR interferometry

    Science.gov (United States)

    Chen, Yan-Ling; Huang, Cheng; Ding, Xiao-Li; Li, Zhi-Wei

    2006-12-01

    InSAR (Interferometric Synthetic Aperture Radar) and D-InSAR (Differential InSAR) are rapidly developed new technologies of space geodesy during the late 20th century, and now obviously become hot research topics in the field of microwave remote sensing. Compared with the other sensors, InSAR possesses many incomparable advantages such as the capability to work at all-time and under all weather, very high spatial resolution and strong penetrability through the ground surface. This paper introduces general status of SAR, InSAR, D-InSAR technology, and the principles of InSAR and D-InSAR. New theories and the potential problems of (D-)InSAR technology are largely discussed, including multi-baseline interferometry, Pol-InSAR technique, the correction of atmospheric effects, permanent Scatterers method, the synthesization technique between InSAR and GPS, LIDAR etc., and the InSAR parallel algorithm. Then the new applications of InSAR and D-InSAR are described in detail including 3D topographic mapping, deformation monitoring (including surface subsidence, landside monitoring and ITRF's foundation and maintenance, etc.), thematic mapping (including agriculture and forestry, oceanic surveying and flood monitoring, etc.) and meteorology etc.. Finally, the prospect and future trends in InSAR development are summarized.

  14. Sea surface slicks measured by SAR

    International Nuclear Information System (INIS)

    The Synthetic Aperture Radar (SAR) system capability to detect and characterize marine surface slicks was tested during the SAR-580 experiment in the northern Adriatic Sea, offshore the Venice coast, in October 1990. Two small artificial slicks of oleyl alcohol were produced in an area around the oceanographic platform of the Italian National Research Council (CNR). The oleyl alcohol produces a damping of the sea centimetric waves, which has been measured by an airborne two band (C and X) SAR, by a tower based 3 band (L, S and C) scatterometer and by a wave gauge, installed on board the platform, which measures the instantaneous sea surface elevation in the range form gravity up to capillary waves. The good agreement among measures proves that multi-frequency SAR is able to detect and characterized sea surface films. Slicks in SAR images taken during SIR-C/X-SAR mission in 1994 have been analysed on the basis of these results and L-band measurements of spatial attenuation near the borders of the slicks have been done, in order to test the slicks detectability using single-band SAR images

  15. SARS - infectious disease of 21st century

    Directory of Open Access Journals (Sweden)

    Tjandra Y. Aditama

    2005-03-01

    Full Text Available Severe acute respiratory syndrome (SARS is an emerging viral infectious disease. According to the World Health Organization, a suspected case of SARS is defined as documented fever (temperature >38°C, lower respiratory tract symptoms, and contact with a person believed to have had SARS or history of travel to an area of documented transmission. A probable case is a suspected case with chest radiographic findings of pneumonia, acute respiratory distress syndrome (ARDS, or an unexplained respiratory illness resulting in death, with autopsy findings of ARDS without identifiable cause. In this article some SARS epidemiological data in Indonesia will also presented. There are 7 SARS suspected cases and 2 probable cases were registered in Indonesia on the period of 1 March to 9 July 2003, and no more cases were reported after that time. How will be SARS progression in the future will be a subject of discussion among scientist, and we will have to wait and be prepared for any development might occur. (Med J Indones 2005; 14: 59-63Keywords: SARS, Case Definition, Etiology, Indonesia

  16. DInSAR Processing with Polarimetric Data Procesado DinSAR con datos polarimetricos Processament DInSAR amb dades polarimètriques

    OpenAIRE

    Monells Miralles, Daniel

    2011-01-01

    English: Study of the uses of orbital polarimetric data for the survey of terrain subsidence through SAR Differential interferometry (DInSAR). Castellano: Estudio del uso de datos polarimetricos orbitales para la monitorizació de la subsidencia del terreno mediante Interferometría Diferencial SAR (DInSAR) Català: Estudi de l'ús de dades polarimetriques orbitals per la monitorització de la subsidència del terreny mitjançant Interferometria diferencial SAR (DInSAR).

  17. First Results from an Airborne Ka-band SAR Using SweepSAR and Digital Beamforming

    Science.gov (United States)

    Sadowy, Gregory; Ghaemi, Hirad; Hensley, Scott

    2012-01-01

    NASA/JPL has developed SweepSAR technique that breaks typical Synthetic Aperture Radar (SAR) trade space using time-dependent multi-beam DBF on receive. Developing SweepSAR implementation using array-fed reflector for proposed DESDynI Earth Radar Mission concept. Performed first-of-a-kind airborne demonstration of the SweepSAR concept at Ka-band (35.6 GHz). Validated calibration and antenna pattern data sufficient for beam forming in elevation. (1) Provides validation evidence that the proposed Deformation Ecosystem Structure Dynamics of Ice (DESDynI) SAR architecture is sound. (2) Functions well even with large variations in receiver gain / phase. Future plans include using prototype DESDynI SAR digital flight hardware to do the beam forming in real-time onboard the aircraft.

  18. Analysis of Resolution of Bistatic SAR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the spatial resolutions at different directions of bistatic synthetic aperture radar (BiSAR) have been derived from the ambiguity function. Compared with monostatic signal to noise ratio, BiSAR's resolutions of a fixed point target are varying with slow time since BiSAR system is space-variant. Constraints for the assumption of space-invariant bistatic topology are proposed in the paper. Moreover, under the assumption of invariance, the change of resolutions at different point in the image scene is taken into account, and we have specified two key parameters that affect resolutions directly and analyzed the way how they influence on the resolutions.

  19. SAR ATR Based on Convolutional Neural Network

    Directory of Open Access Journals (Sweden)

    Tian Zhuangzhuang

    2016-06-01

    Full Text Available This study presents a new method of Synthetic Aperture Radar (SAR image target recognition based on a convolutional neural network. First, we introduce a class separability measure into the cost function to improve this network’s ability to distinguish between categories. Then, we extract SAR image features using the improved convolutional neural network and classify these features using a support vector machine. Experimental results using moving and stationary target acquisition and recognition SAR datasets prove the validity of this method.

  20. Review of Road Extraction Methods from SAR Image

    International Nuclear Information System (INIS)

    Road extraction methods from SAR Image are important in the field of SAR image recognition and detection. In the past few decades, scholars at home and abroad have done a lot of experiments and researches. Through the analysis of the current situation, it firstly introduces the road characteristics of SAR image and basic strategies of road extraction. Then, the existing road extraction methods from SAR image are summarized. Finally, the prospective road extraction researches from SAR image are put forward

  1. Similarity measures of full polarimetric SAR images fusion for improved SAR image matching

    Science.gov (United States)

    Ding, H.

    2015-06-01

    China's first airborne SAR mapping system (CASMSAR) developed by Chinese Academy of Surveying and Mapping can acquire high-resolution and full polarimetric (HH, HV, VH and VV) Synthetic aperture radar (SAR) data. It has the ability to acquire X-band full polarimetric SAR data at a resolution of 0.5m. However, the existence of speckles which is inherent in SAR imagery affects visual interpretation and image processing badly, and challenges the assumption that conjugate points appear similar to each other in matching processing. In addition, researches show that speckles are multiplicative speckles, and most similarity measures of SAR image matching are sensitive to them. Thus, matching outcomes of SAR images acquired by most similarity measures are not reliable and with bad accuracy. Meanwhile, every polarimetric SAR image has different backscattering information of objects from each other and four polarimetric SAR data contain most basic and a large amount of redundancy information to improve matching. Therefore, we introduced logarithmically transformation and a stereo matching similarity measure into airborne full polarimetric SAR imagery. Firstly, in order to transform the multiplicative speckles into additivity ones and weaken speckles' influence on similarity measure, logarithmically transformation have to be taken to all images. Secondly, to prevent performance degradation of similarity measure caused by speckles, measure must be free or insensitive of additivity speckles. Thus, we introduced a stereo matching similarity measure, called Normalized Cross-Correlation (NCC), into full polarimetric SAR image matching. Thirdly, to take advantage of multi-polarimetric data and preserve the best similarity measure value, four measure values calculated between left and right single polarimetric SAR images are fused as final measure value for matching. The method was tested for matching under CASMSAR data. The results showed that the method delivered an effective

  2. Enhancement of SAR Image Resolution with Implementation of Circular GB-SAR System

    OpenAIRE

    Neravati, Dheeraj Nehru

    2013-01-01

    Radars were used for surveillance and remote sensing but nowadays they handle a vast range of applications, radar imagery being one of them. The need for high resolution images was inevitable which lead to Synthetic Aperture Radar (SAR) systems. SAR plays a prominent role in remote sensing applications and geophysical studies. SAR is an imaging radar which inherits advantages over conventional optic sensors since they can be used irrespective of the climatic conditions and sunlight due to the...

  3. Evaluation of InSAR and TomoSAR for Monitoring Deformations Caused by Mining in a Mountainous Area with High Resolution Satellite-Based SAR

    Directory of Open Access Journals (Sweden)

    Donglie Liu

    2014-02-01

    Full Text Available Interferometric Synthetic Aperture Radar (InSAR and Differential Interferometric Synthetic Aperture Radar (DInSAR have shown numerous applications for subsidence monitoring. In the past 10 years, the Persistent Scatterer InSAR (PSI and Small BAseline Subset (SBAS approaches were developed to overcome the problem of decorrelation and atmospheric effects, which are common in interferograms. However, DInSAR or PSI applications in rural areas, especially in mountainous regions, can be extremely challenging. In this study we have employed a combined technique, i.e., SBAS-DInSAR, to a mountainous area that is severely affected by mining activities. In addition, L-band (ALOS and C-band (ENVISAT data sets, 21 TerraSAR-X images provided by German Aerospace Center (DLR with a high resolution have been used. In order to evaluate the ability of TerraSAR-X for mining monitoring, we present a case study of TerraSAR-X SAR images for Subsidence Hazard Boundary (SHB extraction. The resulting data analysis gives an initial evaluation of InSAR applications within a mountainous region where fast movements and big phase gradients are common. Moreover, the experiment of four-dimension (4-D Tomography SAR (TomoSAR for structure monitoring inside the mining area indicates a potential near all-wave monitoring, which is an extension of conventional InSAR.

  4. Advanced Antenna for Digital Beamforming SAR Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Develop a wideband (500 MHz) L-band phased-array antenna for airborne Synthetic Aperture Radar (SAR) applications based on a novel approach that will make possible...

  5. Statistical Modeling of SAR Images: A Survey

    Directory of Open Access Journals (Sweden)

    Gui Gao

    2010-01-01

    Full Text Available Statistical modeling is essential to SAR (Synthetic Aperture Radar image interpretation. It aims to describe SAR images through statistical methods and reveal the characteristics of these images. Moreover, statistical modeling can provide a technical support for a comprehensive understanding of terrain scattering mechanism, which helps to develop algorithms for effective image interpretation and creditable image simulation. Numerous statistical models have been developed to describe SAR image data, and the purpose of this paper is to categorize and evaluate these models. We first summarize the development history and the current researching state of statistical modeling, then different SAR image models developed from the product model are mainly discussed in detail. Relevant issues are also discussed. Several promising directions for future research are concluded at last.

  6. Satellite sar detection of hurricane helene (2006)

    DEFF Research Database (Denmark)

    Ju, Lian; Cheng, Yongcun; Xu, Qing;

    2013-01-01

    In this paper, the wind structure of hurricane Helene (2006) over the Atlantic Ocean is investigated from a C-band RADARSAT-1 synthetic aperture radar (SAR) image acquired on 20 September 2006. First, the characteristics, e.g., the center, scale and area of the hurricane eye (HE) are determined....... There is a good agreement between the SAR-estimated HE center location and the best track data from the National Hurricane Center. The wind speeds at 10 m above the ocean surface are also retrieved from the SAR data using the geophysical model function (GMF), CMOD5, and compared with in situ wind speed...... observations from the stepped frequency microwave radiometer (SFMR) on NOAA P3 aircraft. All the results show the capability of hurricane monitoring by satellite SAR. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE)....

  7. IMPROVED ALGORITHM FOR STRIPMAP SAR IMAGING

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper proposes a calibrated method for quasi-broadside side-looking mode SAR imaging with small squint angle and an improved method named as phase alignment algorithm of subaperture reference signal. The calibrated method adopts subaperture spotlighting algorithm of broadside mode to image the real data of quasi-broadside mode SAR, then based on the obtained image the small squint angle is estimated and the calibrated subaperture spotlighting algorithm of squint mode is employed to obtain the final image. The calibrated method can calibrate the abnormal region and obtain the correct image. The phase alignment algorithm of subaperture reference signal adjusts phases of respective subaperture reference signals in order to make them be in phase and constructs a new spotlighting window function for SAR imaging. Theoretical analysis shows that with the same sample data, the improved method can increase SAR imaging area in azimuth dimension. The methods are verified by the results of computer simulation.

  8. Satellite sar detection of hurricane helene (2006)

    DEFF Research Database (Denmark)

    Ju, Lian; Cheng, Yongcun; Xu, Qing; Zhang, Guosheng

    In this paper, the wind structure of hurricane Helene (2006) over the Atlantic Ocean is investigated from a C-band RADARSAT-1 synthetic aperture radar (SAR) image acquired on 20 September 2006. First, the characteristics, e.g., the center, scale and area of the hurricane eye (HE) are determined....... There is a good agreement between the SAR-estimated HE center location and the best track data from the National Hurricane Center. The wind speeds at 10 m above the ocean surface are also retrieved from the SAR data using the geophysical model function (GMF), CMOD5, and compared with in situ wind speed...... observations from the stepped frequency microwave radiometer (SFMR) on NOAA P3 aircraft. All the results show the capability of hurricane monitoring by satellite SAR. Copyright © 2013 by the International Society of Offshore and Polar Engineers (ISOPE)....

  9. Polarimetric SAR Interferometry Evaluation in Mangroves

    Science.gov (United States)

    Lee, Seung-Kuk; Fatoyinbo,Temilola; Osmanoglu, Batuhan; Sun, Guoqing

    2014-01-01

    TanDEM-X (TDX) enables to generate an interferometric coherence without temporal decorrelation effect that is the most critical factor for a successful Pol-InSAR inversion, as have recently been used for forest parameter retrieval. This paper presents mangrove forest height estimation only using single-pass/single-baseline/dual-polarization TDX data by means of new dual-Pol-InSAR inversion technique. To overcome a lack of one polarization in a conventional Pol- InSAR inversion (i.e. an underdetermined problem), the ground phase in the Pol-InSAR model is directly estimated from TDX interferograms assuming flat underlying topography in mangrove forest. The inversion result is validated against lidar measurement data (NASA's G-LiHT data).

  10. Work session on the SAR. Pt. 2

    International Nuclear Information System (INIS)

    The present paper contains the tables of the contribution of K. Burkart 'Work Session on the SAR' to the IAEA Interregional Training Course held in Sept/Oct. 1980 at the Kernforschungszentrum Karlsruhe. (RW)

  11. A Comparison of the Daphnids, Ceriodaphnia dubia and Daphnia ambigua, for their Utilization in Routine Toxicity Testing in the Southeastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Harmon, S.M.; Chandler, G.T.; Specht, W.L.

    2003-02-18

    U.S. regulatory agencies commonly require effluent toxicity testing with Ceriodaphnia dubia- a practice which has led to the criticism that this species and test protocol often does not reflect local taxa nor site-specific conditions. Using an indigenous test species may produce a more realistic model of local effects and may minimize test endpoint variance due to regional differences in water quality. This study addressed the substitution of C. dubia with Daphnia ambigua for toxicity testing in the southeastern United States. This investigation determined that D. ambigua could be laboratory cultured with only minimal changes to established regulatory protocol, and that the life-cycle characteristics of this species were conducive to traditional acute and chronic aquatic toxicity test methods used with other daphnids. Acute toxicity tests showed that D. ambigua was less sensitive to some toxicants (sodium chloride, copper sulfate, and sodium lauryl sulfate) yet more sensitive to others (chlorpyrifos). Chronic tests with copper sulfate and sodium chloride resulted in lower EC50s for D. ambigua reproduction with both compounds. When exposed to low-alkalinity, low-pH stream waters typical of many southeastern United States watersheds, C. dubia demonstrated a significant reproductive depression in two of three streams tested, while D. ambigua experienced no chronic effect. These results suggest that D. ambigua may serve as a suitable surrogate for C. dubia as an toxicity indicator species in these types of receiving streams.

  12. Static renewal tests using Pimephales promelas (fathead minnows) and Ceriodaphnia dubia (daphnids). Clinch River-Environmental Restoration Program (CR-ERP) study, ambient water toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Simbeck, D.J.

    1994-12-31

    Clinch River-Environmental Restoration Program (CR-ERP) personnel and Tennessee Valley Authority (TVA) personnel conducted a study during the week of January 25--February 1, 1994. The organisms specified for testing were larval fathead minnows, Pimephales promelas, and the daphnid, Ceriodaphnia dubia. Surface water samples were collected from Clinch River Mile 9.0, Poplar Creek Mile 1.0, and Poplar Creek Mile 2.9 on January 24, 26, and 28. Samples were partitioned and provided to the CR-ERP and TVA toxicology laboratories for testing. Exposure of test organisms to these samples resulted in no toxicity (survival or growth) to fathead minnows; however, toxicity to daphnids was demonstrated in undiluted samples from Poplar Creek Mile 1.0 in testing conducted by TVA based on hypothesis testing of data. Point estimation (IC{sub 25}) analysis of the data, however, showed no toxicity in PCM 1.0 samples. Attachments to this report include: Chain of custody forms -- originals; Toxicity test bench sheets and statistical analyses; Meter calibrations; and Reference toxicant test information.

  13. A revised radiometric normalisation standard for SAR

    OpenAIRE

    Small, D.; N. Miranda; Meier, E

    2009-01-01

    Improved geometric accuracy in SAR sensors implies that more complex models of the Earth may be used not only to geometrically rectify imagery, but also to more robustly calibrate their radiometry. Current beta, sigma, and gamma nought SAR radiometry conventions all assume a simple “flat as Kansas” Earth ellipsoid model. We complement these simple models with improved radiometric calibration that accounts for local terrain variations. In the era of ERS-1 and RADARSAT-1, image geolocation a...

  14. On Bistatic Forward-looking SAR Imaging

    OpenAIRE

    Vu, Viet Thuy; Pettersson, Mats

    2014-01-01

    Left/right ambiguity and low angular (azimuth) resolution are severe problems for monostatic forward-looking SAR imaging. It is strongly believed that these technical issues can definitely be solved with bistatic forward-looking SAR. The analysis presented in this paper points out that the left/right ambiguity problem still exits. However, an appropriate selection of the position of bistatic base line and antenna beamwidth allows us to conceal it. The paper also gives some recommendations whi...

  15. SAR ATR Based on Convolutional Neural Network

    OpenAIRE

    Tian Zhuangzhuang; Zhan Ronghui; Hu Jiemin; Zhang Jun

    2016-01-01

    This study presents a new method of Synthetic Aperture Radar (SAR) image target recognition based on a convolutional neural network. First, we introduce a class separability measure into the cost function to improve this network’s ability to distinguish between categories. Then, we extract SAR image features using the improved convolutional neural network and classify these features using a support vector machine. Experimental results using moving and stationary target acquisition and recogni...

  16. Ambiguities and Image Quality in Staggered SAR

    OpenAIRE

    Villano, Michelangelo; Krieger, Gerhard; Moreira, Alberto

    2015-01-01

    Staggered SAR is an innovative synthetic aperture radar (SAR) concept, where the pulse repetition interval (PRI) is continuously varied. This, together with digital beamforming (DBF) in elevation, allows high-resolution imaging of a wide continuous swath without the need for a long antenna with multiple azimuth apertures. As an additional benefit, the energy of range and azimuth ambiguities is spread over large areas: Ambiguities therefore appear in the image as a noise-like disturbance rathe...

  17. Exploitation of TerraSAR-X

    Science.gov (United States)

    Herrmann, Jorg

    2004-01-01

    InfoTerra is an innovative market-derived EO-services concept with end-to-end products and service chains addressing end user information requirements in existing and new markets, with the advantage of a dedicated SAR satellite system TerraSAR (L+X-band) featuring high spatial and thematic resolution. The services will be provided from integrated value chains in a network with complementary partners, benefiting from most up-to-date and reliable image acquisition. The service development has been initiated in 1998 running in parallel to the TerraSAR space and ground system implementation. Infoterra, a new geo-information services company founded in 2001, implements the business concept. TerraSAR-X will be the first system element being available in 2006. The X-band SAR capability enables various applications, e.g. change detection to rationalize updating of cartographic databases; forest inventories, and de-/afforestation monitoring; crop stand density monitoring to support optimized fungicide application; land use monitoring in support of environmental control. A key challenge addressed in the exploitation development is the largely automated and quality controlled large area processing and feature extraction. The high resolution, multi-polarization, and multi-mode TerraSAR-X data source will considerably improve the short-term event observation from space. Reception of data via dedicated ground stations of customers or partners will also be offered.

  18. Ionospheric Specifications for SAR Interferometry (ISSI)

    Science.gov (United States)

    Pi, Xiaoqing; Chapman, Bruce D; Freeman, Anthony; Szeliga, Walter; Buckley, Sean M.; Rosen, Paul A.; Lavalle, Marco

    2013-01-01

    The ISSI software package is designed to image the ionosphere from space by calibrating and processing polarimetric synthetic aperture radar (PolSAR) data collected from low Earth orbit satellites. Signals transmitted and received by a PolSAR are subject to the Faraday rotation effect as they traverse the magnetized ionosphere. The ISSI algorithms combine the horizontally and vertically polarized (with respect to the radar system) SAR signals to estimate Faraday rotation and ionospheric total electron content (TEC) with spatial resolutions of sub-kilometers to kilometers, and to derive radar system calibration parameters. The ISSI software package has been designed and developed to integrate the algorithms, process PolSAR data, and image as well as visualize the ionospheric measurements. A number of tests have been conducted using ISSI with PolSAR data collected from various latitude regions using the phase array-type L-band synthetic aperture radar (PALSAR) onboard Japan Aerospace Exploration Agency's Advanced Land Observing Satellite mission, and also with Global Positioning System data. These tests have demonstrated and validated SAR-derived ionospheric images and data correction algorithms.

  19. Anti-SARS virus antibody responses against human SARS-associated coronavirus and animal SARS-associated coronavirus-like virus

    Institute of Scientific and Technical Information of China (English)

    王鸣; 徐慧芳; 莫自耀; 郑伯健; 高阳; 顾菁; 秦鹏哲; 张周斌; 邹晓忠; 梁彩云; 赵宇腾; 高凯

    2004-01-01

    @@ Severe acute respiratory syndrome (SARS) is an infectious disease first recognized in November 2002 in Guangdong province, China. It was spread to many countries all over the world within a few months.1,2 By April 2003, SARS-associated coronavirus (SARS-CoV) was found to be the etiological agent.

  20. UAVSAR: InSAR and PolSAR Test Bed for the Proposed NI-SAR Mission

    Science.gov (United States)

    Jones, C. E.; Hensley, S.; Lou, Y.

    2014-12-01

    UAVSAR, which first became operational in 2009, has served as an operational testbed for the NI-SAR L-band radar concept and a unique instrument in its own right. UAVSAR supports a broad array of basic and applied geoscience, covering on smaller scale all the disciplines NI-SAR would be able to address on a global scale. Although designed specifically to provide high accuracy repeated flight tracks and precise imaging geometry for InSAR-based solid earth studies, its fully polarimetric operation, low noise, and consistent calibration accuracy has made it a premier instrument for PolSAR-based studies also. Since 2009 it has successfully imaged more than 16 million km2 and >4300 quad-polarimetric data products are now publicly available online. Upgrades made in the last year to automate the repeat track processing serve as a model for generating large volumes of InSAR products: Since January 2014 more than 700 interferometric products have been released, exceeding the output of all previous years combined. Standardly available products now include browse images of all InSAR acquisitions and coregistered single-look complex image stacks suitable for standard time series analysis. Here we present an overview of the wide range of studies utilizing UAVSAR data including those based on polarimetry and pair-wise and times series interferometry, highlighting both the unique capabilities of UAVSAR and the ways in which NI-SAR would be able to dramatically extend the capabilities. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

  1. Use of SAR data for proliferation monitoring

    International Nuclear Information System (INIS)

    Synthetic Aperture Radar (SAR) is an active and coherent system. SAR images are complex data which contain both amplitude and phase information. The analysis of single SAR data required a very good experience and a good understanding of SAR geometry regarding layover, shadowing, texture and speckle. Image analyst can depicts and describes most of the facilities related to nuclear proliferation and weapons of mass destruction (WMD). The Amplitude Change Detection (ACD) technique consists of a combination of two or three SAR amplitude data acquired with similar orbit and frequency parameters on different dates. That technique provides a very good overview of the changes and particularly regarding vehicles activity and constructions ongoing within the area of interest over the monitoring period. One of the particularities of the SAR systems is to be coherent. The phase of a single image is not exploitable. Thus when two or more SAR data have been acquired with identical orbit and frequency parameters, the phases shift are indicators of changes such as structural changes, terrain subsidence or motion. The Multi-Temporal Coherence (MTC) product merged the two type of information previously detailed: the ACD and coherence analysis. It consists of the combination of two amplitude images and the corresponding coherence computed image. The MTC image may highlights changes between two states of a target which on the ACD analysis appeared unchanged. EUSC uses the difference interferometry techniques in order to estimate volumes that have changed between two acquisition dates. The paper is followed by the slides of the presentation. (A.C.)

  2. Investigation of ionospheric effects on SAR Interferometry (InSAR): A case study of Hong Kong

    Science.gov (United States)

    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.

  3. The impact of SARS on hospital performance

    Directory of Open Access Journals (Sweden)

    Chen Ran-Chou

    2008-11-01

    Full Text Available Abstract Background During the SARS epidemic, healthcare utilization and medical services decreased significantly. However, the long-term impact of SARS on hospital performance needs to be further discussed. Methods A municipal hospital in Taipei City was shut down for a month due to SARS and then became the designated SARS and infectious disease hospital for the city. This study collected the outpatient, inpatient and emergency service volumes for every year from April to March over four years. Average monthly service amount ± standard deviation were used to compare patient volume for the whole hospital, as well as the outpatient numbers accessing different departments. The ARIMA model of outpatient volume in the pre-SARS year was developed. Results The average monthly service volume of outpatient visits for the base year 2002 was 52317 ± 4204 visits per month, and number for 2003 and the following two years were 55%, 82% and 84% of the base year respectively. The average emergency service volume was 4382 ± 356 visits per month at the base year and this became 45%, 77% and 87% of the base year for the following three years respectively. Average inpatient service volume was 8520 ± 909 inpatient days per month at the base year becoming 43%, 81% and 87% of the base year for the following three years respectively. Only the emergency service volume had recovered to the level of a non-significant difference at the second year after SARS. In addition, the departments of family medicine, metabolism and nephrology reached the 2002 patient number in 2003. The ARIMA (2,1,0 model was the most suitable for outpatient volume in pre-SARS year. The MAPE of the ARIMA (2,1,0 model for the pre-SARS year was 6.9%, and 43.2%, 10.6%, 6.2% for following 3 years. Conclusion This study demonstrates that if a hospital is completely shut down due to SARS or a similar disease, the impact is longer than previous reported and different departments may experience

  4. SARS revisited: managing "outbreaks" with "communications".

    Science.gov (United States)

    Menon, K U

    2006-05-01

    "Risk communications" has acquired some importance in the wake of our experience of SARS. Handled well, it helps to build mutual respect between a government or an organisation and the target groups with which it is communicating. It helps nurture public trust and confidence in getting over the crisis. The World Health Organization (WHO) has also come to recognise its importance after SARS and organised the first Expert Consultation on Outbreak Communications conference in Singapore in September 2004. This article assesses the context and the key features which worked to Singapore's advantage. Looking at the data now widely available on the Internet of the experience of SARS-infected countries like China, Taiwan, Canada, the article identifies the key areas of strategic communications in which Singapore fared particularly well. Another issue discussed is whether Singapore's experience has universal applicability or whether it is limited because of Singapore's unique cultural, historical and geographical circumstances. Finally, the article also looks at some of the post-SARS enhancements that have been put in place following the lessons learnt from SARS and the need to confront new infectious outbreaks like avian flu. PMID:16830005

  5. A modified algorithm for SAR parallel imaging

    Institute of Scientific and Technical Information of China (English)

    HU Ju-rong; WANG Fei; CAO Ning; LU Hao

    2009-01-01

    Synthetic aperture radar can provide two dimension images by converting the acquired echoed SAR signal to targets coordinate and reflectivity. With the advancement of sophisticated SAR signal processing, more and more SAR imaging methods have been proposed for synthetic aperture radar which works at near field and the Fresnel approximation is not appropriate. Time domain correlation is a kind of digital reconstruction method based on processing the synthetic aperture radar data in the two-dimensional frequency domain via Fourier transform. It reconstructs SAR image via simply correlation without any need for approximation or interpolation. But its high computational cost for correlation makes it unsuitable for real time imaging. In order to reduce the computational burden a modified algorithm about time domain correlation was given in this paper. It also can take full advantage of parallel computations of the imaging processor. Its practical implementation was proposed and the preliminary simulation results were presented. Simulation results show that the proposed algorithm is a computationally efficient way of implementing the reconstruction in real time SAR image processing.

  6. Acute toxicity over Ceriodaphnia silvestrii and Daphnia magna: Bioassays with water samples from a dam under the influence of uranium mine and with manganese

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Carla R.; Nascimento, Heliana de Azevedo Franco do; Silverio, Emilia Gabriela Costa; Bruschi, Armando Luis; Roque, Claudio Vitor; Nascimento, Marcos Roberto L.; Bonifacio, Rodrigo Leandro, E-mail: carlarolimferrari@yahoo.com.br, E-mail: hazevedo@cnen.gov.br, E-mail: emiliagcsilverio@hotmail.com, E-mail: abruschi@cnen.gov.br, E-mail: cvroque@cnen.gov.br, E-mail: pmarcos@cnen.gov.br, E-mail: rodrigo@cnen.gov.br [Comissao Nacional de Energia Nuclear (LAPOC/CNEN-MG), Pocos de Caldas, MG (Brazil). Laboratorio de Pocos de Caldas; Rodgher, Suzelei [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Sao Jose dos Campos, SP (Brazil). Dep. de Engenharia Ambiental

    2015-07-01

    Treated effluents from uranium mine with acid mine drainage can impact receiving water bodies. AMD is relevant from the environmental view due to the large volume of effluents generated, known to affect aquatic biota. Studies show that one of the main problems of treated effluents released by UTM/INB on the catchment basin of Ribeirao das Antas is associated to high Mn values in water samples. In this context, acute 48-h toxicity tests with Mn were conducted with Ceriodaphnia silvestrii and Daphnia magna to determine the No Observed Effect Concentration (NOEC) and the Observed Effect Concentration (OEC) in laboratory bioassays and to verify the potential toxicity of the Mn in face of concentrations found in water samples from the Antas Dam, which receives treated effluents from UTM/INB. In this study, preliminary results of acute toxicity for C. silvestrii indicated OEC values between 9.0 and 10.0 mg Mn/L and NOEC < 3.0 mg Mn/L. For D. magna, OEC and NOEC concentrations were ≥ 30 mg Mn/L and ≤ 80 mg Mn/L, respectively. It was verified that Mn concentrations determined in environmental samples registered the highest value at 1.75 mg Mn/L, below the OEC concentrations recorded for both species. Since manganese occurs in the composition of the effluent that may contain other stable and radioactive elements, complementary ecotoxicological tests must be conducted, aiming at the assessment of synergistic and antagonistic effects of the chemical mixture that makes up the radioactive effluents that are treated and released at the Antas Dam. Such bioassays are underway in the Radioecology Laboratory at LAPOC/CNEN. (author)

  7. Influence of inorganic anions on metals release from oil sands coke and on toxicity of nickel and vanadium to Ceriodaphnia dubia.

    Science.gov (United States)

    Puttaswamy, Naveen; Liber, Karsten

    2012-02-01

    In a previous study it was shown that pH significantly influences the release of metals from oil sands coke, particularly Ni and V which were identified as the cause of coke leachate toxicity. Coke comes in contact with oil sands process water (OSPW) during its transport to and long term storage in reclamation landscapes. However, the influence of dominant inorganic anions present in OSPW (i.e. HCO(3)(-), Cl(-) and SO(4)(2-)) on metals release from coke and on speciation and toxicity of Ni and V, has not been characterized before. Coke was subjected to a 15-d batch leaching process at four levels of HCO(3)(-), Cl(-) and SO(4)(2-) to determine the influence on metals release and speciation. Further, the effects of each of the three anions on Ni and V toxicity, as well as the mixture toxicity of Ni and V, were assessed using the three-brood Ceriodaphnia dubia test. Inorganic anions had a significant influence on the type and amount of metals released from coke. Specifically, sulfate increased the mobilization of cationic metals (e.g. Ni, Fe, Mn and Zn), whereas bicarbonate enhanced the release of oxyanion forming metals (e.g. Al, As, Mo and V) from coke. Chloride had no particular effect on the type and amount of metals released. With respect to toxicity, elevated bicarbonate levels decreased the 7-d Ni IC50 from 6.3 to 2.3 μg L(-1), whereas sulfate showed an ameliorative effect against V toxicity to C. dubia. In combination, Ni and V acted additively at their highest sub-lethal concentrations. Aqueous chemistry and toxicity of Ni and V are discussed with the goal of informing reclamation efforts at the Athabasca oil sands. PMID:22138340

  8. Acute toxicity over Ceriodaphnia silvestrii and Daphnia magna: Bioassays with water samples from a dam under the influence of uranium mine and with manganese

    International Nuclear Information System (INIS)

    Treated effluents from uranium mine with acid mine drainage can impact receiving water bodies. AMD is relevant from the environmental view due to the large volume of effluents generated, known to affect aquatic biota. Studies show that one of the main problems of treated effluents released by UTM/INB on the catchment basin of Ribeirao das Antas is associated to high Mn values in water samples. In this context, acute 48-h toxicity tests with Mn were conducted with Ceriodaphnia silvestrii and Daphnia magna to determine the No Observed Effect Concentration (NOEC) and the Observed Effect Concentration (OEC) in laboratory bioassays and to verify the potential toxicity of the Mn in face of concentrations found in water samples from the Antas Dam, which receives treated effluents from UTM/INB. In this study, preliminary results of acute toxicity for C. silvestrii indicated OEC values between 9.0 and 10.0 mg Mn/L and NOEC < 3.0 mg Mn/L. For D. magna, OEC and NOEC concentrations were ≥ 30 mg Mn/L and ≤ 80 mg Mn/L, respectively. It was verified that Mn concentrations determined in environmental samples registered the highest value at 1.75 mg Mn/L, below the OEC concentrations recorded for both species. Since manganese occurs in the composition of the effluent that may contain other stable and radioactive elements, complementary ecotoxicological tests must be conducted, aiming at the assessment of synergistic and antagonistic effects of the chemical mixture that makes up the radioactive effluents that are treated and released at the Antas Dam. Such bioassays are underway in the Radioecology Laboratory at LAPOC/CNEN. (author)

  9. Exploration of Advanced Bistatic SAR Experiments (in English

    Directory of Open Access Journals (Sweden)

    Deng Yun-kai

    2014-02-01

    Full Text Available This study concentrates on the results of several advanced hybrid bistatic SAR experiments. The hybrid bistatic configuration applies to the case in which the transmitter and receiver are mounted on different types of platforms, e.g., spaceborne/airborne, airborne/stationary, spaceborne/stationary, and so on. Several hybrid bistatic SAR experiments have been performed successfully, i.e., TerraSAR-X/PAMIR, PAMIR/stationary, and TerraSAR-X/stationary. Furthermore, Multiple Baseline Interferometry SAR (MB-InSAR and Digital Beam-Forming (DBF technologies are validated in the TerraSAR-X/stationary configuration. Note that the DBF experiment results based on the spaceborne illuminator are discussed for the first time in SAR community. In addition, this paper emphasizes imaging geometry, image analysis, and focusing results.

  10. Simultaneous Observation Data of GB-SAR/PiSAR to Detect Flooding in an Urban Area

    Directory of Open Access Journals (Sweden)

    Manabu Watanabe

    2010-01-01

    Full Text Available We analyzed simultaneous observation data with ground-based synthetic aperture radar (GB-SAR and airborne SAR (PiSAR over a flood test site at which a simple house was constructed in a field. The PiSAR σ∘ under flood condition was 0.9 to 3.4 dB higher than that under nonflood condition. GB-SAR gives high spatial resolution as we could identify a single scattering component and a double bounce component from the house. GB-SAR showed that the σ∘ difference between the flooding and nonflooding conditions came from the double bounce scattering. We also confirm that the entropy is a sensitive parameter in the eigenvalue decomposition parameters, if the scattering process is dominated by the double bounce scattering. We conclude that σ∘ and entropy are a good parameter to be used to detect flooding, not only in agricultural and forest regions, but also in urban areas. We also conclude that GB-SAR is a powerful tool to supplement satellite and airborne observation, which has a relatively low spatial resolution.

  11. Simultaneous Observation Data of GB-SAR/PiSAR to Detect Flooding in an Urban Area

    Directory of Open Access Journals (Sweden)

    Shimada Masanobu

    2010-01-01

    Full Text Available Abstract We analyzed simultaneous observation data with ground-based synthetic aperture radar (GB-SAR and airborne SAR (PiSAR over a flood test site at which a simple house was constructed in a field. The PiSAR under flood condition was 0.9 to 3.4 dB higher than that under nonflood condition. GB-SAR gives high spatial resolution as we could identify a single scattering component and a double bounce component from the house. GB-SAR showed that the difference between the flooding and nonflooding conditions came from the double bounce scattering. We also confirm that the entropy is a sensitive parameter in the eigenvalue decomposition parameters, if the scattering process is dominated by the double bounce scattering. We conclude that and entropy are a good parameter to be used to detect flooding, not only in agricultural and forest regions, but also in urban areas. We also conclude that GB-SAR is a powerful tool to supplement satellite and airborne observation, which has a relatively low spatial resolution.

  12. Applications of SAR Interferometry in Earth and Environmental Science Research

    OpenAIRE

    Xiaobing Zhou; Ni-Bin Chang; Shusun Li

    2009-01-01

    This paper provides a review of the progress in regard to the InSAR remote sensing technique and its applications in earth and environmental sciences, especially in the past decade. Basic principles, factors, limits, InSAR sensors, available software packages for the generation of InSAR interferograms were summarized to support future applications. Emphasis was placed on the applications of InSAR in seismology, volcanology, land subsidence/uplift, landslide, glaciology, hydrology, and forestr...

  13. Digital Beamforming and MIMO SAR: Review and New Concepts

    OpenAIRE

    Krieger, Gerhard; Younis, Marwan; Huber, Sigurd; Bordoni, Federica; Patyuchenko, Anton; Kim, Junghyo; Laskowski, Piotr; Villano, Michealangelo; Rommel, Tobias; Lopez-dekker, Paco; Moreira, Alberto

    2012-01-01

    Spaceborne Synthetic Aperture Radar (SAR) is a unique tool for large scale Earth observation, but the current generation of SAR sensors suffers from some fundamental limitations with regard to their imaging and mapping capabilities. To overcome these limitations, several new instrument architectures and SAR imaging modes have been suggested that employ digital beamforming (DBF), multiple aperture data recording and MIMO SAR tech-niques. This paper provides a critical review of these technique...

  14. Monitoring of Surface Deformation in Northern Taiwan Using DInSAR and PSInSAR Techniques

    Directory of Open Access Journals (Sweden)

    Chung-Pai Chang

    2010-01-01

    Full Text Available We investigated the surface deformation of the northern Taiwan area, including the Taipei basin and its surrounding mountainous areas of the last fifteen years using the ERS-1, ERS-2 and ENVISAT SAR images. Although the Taipei basin now is well developed and amenable to research gathering using the Differential Interferometric Synthetic Aperture Radar (DInSAR technique, the mountainous areas surrounding the basin are densely covered with various vegetation throughout different seasons inducing high noise ratio in interferograms. Therefore the DInSAR technique is ineffective for observation of surface deformations of these areas. As a result, we developed the Persistent Scatterer (PS InSAR technique to extract the phase signal of the chosen PS points for this study. Our analysis result shows that the atmospheric disturbance and DEM residual can be successfully reduced and the precise information of surface deformation can be effectively obtained by the PSInSAR technique not only in the basin but also in the mountainous areas. Integrating the DInSAR and PSInSAR results, we observed conspicuous deformation events in northern Taiwan including: (1 the slight uplift in the Western Foothills, the Tatun volcanoes, the Linkou Tableland and the Taoyuan area; (2 the subsidence at the border of the Taipei basin; and (3 relative slight uplift rebound in the center of Taipei basin. The displacements along the Shanchiao, Chinshan, and Kanchiao Faults are large enough to be observed; the Taipei, Hsinchuang, and Nankang Faults are too small and cannot be discerned. Further comparison between the DInSAR, PSInSAR, and their corresponding leveling data shows a very coincidental pattern and measurably improves the authenticity of radar interferometry.

  15. Geologic mapping in Greenland with polarimetric SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Madsen, Søren Nørvang; Brooks, C. K.; Nielsen, T.

    The application of synthetic aperture radar (SAR) for geologic mapping in Greenland is investigated by the Danish Center for Remote Sensing (DCRS) in co-operation with the Danish Lithosphere Centre (DLC). In 1994 a pilot project was conducted in East Greenland. The Danish airborne SAR, EMISAR......, acquired fully polarimetric C-band data which, upon processing and calibration, was interpreted jointly by DCRS and DLC. Several geologic phenomena are readily identified in the SAR imagery, while different lithologies seem to be indistinguishable because they have similar geomorphologies. The geologic...... mapping is complicated by an extreme topography leading to massive shadowing, foreshortening and layover. An artifact characterised by high cross-polarisation is observed behind many sharp mountain ridges. A multi-reflection hypothesis has been investigated without finding the ultimate proof...

  16. Contribution au SAR spatial distribué

    OpenAIRE

    Maréchal, Rozenn

    2006-01-01

    L'obtention d’images à partir de l'émission, de la réception et du traitement d'impulsions radar (SAR) est soumise à différentes contraintes qui limitent les performances telles que la résolution en distance, la résolution en azimut ou la largeur de la Zone imagée (fauchée). Ces limites sont en partie liées à la dimension finie de l’antenne, en particulier dans le cas du SAR spatial. Pour cette raison, on a cherché à étudier la possibilité de mettre au point des systèmes SAR spatiaux distribué...

  17. DESIGN AND ANALYSIS OF MULTI-MODE CLUSTER SAR

    Institute of Scientific and Technical Information of China (English)

    Fan Luhong; Pi Yiming; Hou Yinming

    2004-01-01

    Cluster Synthetic Aperture Radar (SAR) system is composed of a group of spaceborne SAR systems. With its agility of combination, this system can work in several different modes. In this letter, the basic configuration and the working mode of the system are presented.The special performance of the system compared with the conventional SAR system is indicated.

  18. Accuracy assessment of SAR interferometry using the ERS-1

    OpenAIRE

    Broquetas Ibars, Antoni

    1995-01-01

    A SAR raw data simulator and a SAR processor are used as a tool for performance assessment of SAR interferometry algorithms like the multi-baseline and multifrequency. Traditional algorithms have also been tested with real ERS-1 data and validated with a high accuracy reference DEM. Peer Reviewed

  19. Geometric calibration of ERS satellite SAR images

    DEFF Research Database (Denmark)

    Mohr, Johan Jacob; Madsen, Søren Nørvang

    2001-01-01

    Geometric calibration of the European Remote Sensing (ERS) Satellite synthetic aperture radar (SAR) slant range images is important in relation to mapping areas without ground reference points and also in relation to automated processing. The relevant SAR system parameters are discussed and...... calibrated by using the European Space Agency (ESA) transponders at Flevoland. The resulting accuracy of the slant range images corresponds to 10 m horizontally on the ground. The results are verified by using runway intersections and corner reflectors surveyed with differential GPS techniques. Based on a...

  20. Science data collection with polarimetric SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Woelders, Kim; Madsen, Søren Nørvang

    1996-01-01

    Discusses examples on the use of polarimetric SAR in a number of Earth science studies. The studies are presently being conducted by the Danish Center for Remote Sensing. A few studies of the European Space Agency's EMAC programme are also discussed. The Earth science objectives are presented, an...... the potential of polarimetric SAR is discussed and illustrated with data collected by the Danish airborne EMISAR system during a number of experiments in 1994 and 1995. The presentation will include samples of data acquired for the different studies...

  1. Estimating IMU heading error from SAR images.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2009-03-01

    Angular orientation errors of the real antenna for Synthetic Aperture Radar (SAR) will manifest as undesired illumination gradients in SAR images. These gradients can be measured, and the pointing error can be calculated. This can be done for single images, but done more robustly using multi-image methods. Several methods are provided in this report. The pointing error can then be fed back to the navigation Kalman filter to correct for problematic heading (yaw) error drift. This can mitigate the need for uncomfortable and undesired IMU alignment maneuvers such as S-turns.

  2. Wave directional spectrum from SAR imagery

    Digital Repository Service at National Institute of Oceanography (India)

    Fernandes, A.A.; Sarma, Y.V.B.; Menon, H.B.; Vethamony, P.

    zero degrees or nadir incidence, specular reflection dominates while at angles larger than 70?, "shadowing" effect dominates. The theory of imaging of longer ocean waves by all types of radar is discussed in terms of the 'Two-scale' model in which... variation in facet position and the Bragg scattering coefficients of the facets during the finite integration time in which SAR sees the facet (motion effects or velocity bunching). A review of the theory of imaging of ocean waves by SAR is given...

  3. Stochastic dynamic model of SARS spreading

    Institute of Scientific and Technical Information of China (English)

    SHI Yaolin

    2003-01-01

    Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.

  4. SARS: systematic review of treatment effects.

    OpenAIRE

    Stockman, Lauren J.; Richard Bellamy; Paul Garner

    2006-01-01

    Editors' Summary Background. Severe acute respiratory syndrome (SARS) is caused by a virus; the main symptoms are pneumonia and fever. The virus is usually passed on when people sneeze or cough. SARS became a much-talked about disease in 2003, when over 8,000 cases and 774 deaths occurred worldwide. The situation was alarming, because the first-ever cases had only just appeared in 2002, in China, so the best way to treat this new disease was unknown. Not many drugs are effective against virus...

  5. A Review About SAR Technique for Shallow Water Bathymetry Surveys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Synthetic Aperture Radar (SAR) has become one of the important tools for shallow water bathymetry surveys. This has significant economic efficiency compared with the traditional bathymetry surveys. Numerical models have been developed to simulate shallow water bathymetry SAR images. Inversion of these models makes it possible to assess the water depths from SAR images. In this paper, these numerical models of SAR technique are reviewed, and examples are illustrated including in the coastal areas of China. Some issues about SAR technique available and the research orientation in future are also discussed.

  6. Flood Mapping Using InSAR Coherence Map

    OpenAIRE

    Selmi, S.; W. Ben Abdallah; Abdelfatteh, R.

    2014-01-01

    Classic approaches for the detection of flooded areas are based on a static analysis of optical images and/or SAR data during and after the event. In this paper, we aim to extract the flooded zones by using the SAR image coupled with the InSAR coherence. A new formulation of the ratio approach for flood detection is given considering InSAR coherence. Our contribution is to take advantage from the coherence map provided using the InSAR pairs (one before and one after the event) to enh...

  7. Pengaruh Stressor Kerja terhadap Kinerja Pegawai SAR di Kantor SAR Medan Tahun 2014

    OpenAIRE

    Pakpahan, Suzan Fhitriana

    2016-01-01

    Job stressor is one of the problems that arise in the SAR field personnel in the Office of Search and Rescue Agency field caused by excessive workload, stress or time pressure, poor quality of supervision, the political climate of insecurity, inadequate authority to responsibilities, the difference between the value of the company and employees, frustrated and so forth so that in the end the job stressors can affect performance of SAR Medan employee. This study aims to determine the effec...

  8. Living in the Shadow of SARS

    Institute of Scientific and Technical Information of China (English)

    LUZHU

    2003-01-01

    I Was born in April, when spring is in the air, the sun shines, the sky is blue, and the fragrance of lilacs is everywhere. This year's birthday was unforgettable.As the SARS epidemic had broken out in Beijing, it was spent under the threat of this killer disease.

  9. Offshore wind mapping Mediterranean area using SAR

    DEFF Research Database (Denmark)

    Calaudi, Rosamaria; Arena, Felice; Badger, Merete; Sempreviva, Anna Maria

    2013-01-01

    Satellite observations of the ocean surface, for example from Synthetic Aperture Radars (SAR), provide information about the spatial wind variability over large areas. This is of special interest in the Mediterranean Sea, where spatial wind information is only provided by sparse buoys, often with...

  10. Cross-calibration of interferometric SAR data

    DEFF Research Database (Denmark)

    Dall, Jørgen

    2003-01-01

    Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully autom...

  11. Multichannel imaging with the AMBER FMCW SAR

    NARCIS (Netherlands)

    Otten, M.P.G.; Rossum, W.L. van; Graaf, M.W. van der; Vlothuizen, W.J.; Tan, R.G.

    2014-01-01

    An X-band Digital Array Synthetic Aperture Radar for a Short Range Tactical UAV is presented. The Frequency Modulated Continuous Wave radar principle in combination with digital beam forming over 24 receive channels is used to achieve low power and advanced imaging SAR capabilities on small platform

  12. Multi-channel SAR for tactical UAV

    NARCIS (Netherlands)

    Otten, M.P.G.; Maas, A.P.M.; Bolt, R.J.; Graaf, M.W. van der; Huizing, A.G.; Medenblik, H.J.W.; Dorp, P. van

    2011-01-01

    A light weight SAR has been designed and built, suitable for use on short range tactical UAVs. The system consists of a fully digital receive array, and a very compact active transmit antenna. The approximate weight of the complete system is 6 kg, with power consumption below 75 W, depending on the

  13. Epidemic Models for SARS and Measles

    Science.gov (United States)

    Rozema, Edward

    2007-01-01

    Recent events have led to an increased interest in emerging infectious diseases. This article applies various deterministic models to the SARS epidemic of 2003 and a measles outbreak in the Netherlands in 1999-2000. We take a historical approach beginning with the well-known logistic curve and a lesser-known extension popularized by Pearl and Reed…

  14. Acousto-Optical/Electronic Processor For SAR

    Science.gov (United States)

    Bicknell, T. J.; Farr, W. H.

    1992-01-01

    Lightweight, compact, low-power apparatus processes synthetic-aperture-radar (SAR) returns in real time, providing imagery aboard moving aircraft or spacecraft platform. Processor includes optical and electronic subsystems that, together, resolve range and azimuth coordinates of radar targets by combination of spatial and temporal integrations.

  15. Peptide Mimicrying Between SARS Coronavirus Spike Protein and Human Proteins Reacts with SARS Patient Serum

    Directory of Open Access Journals (Sweden)

    K.-Y. Hwa

    2008-01-01

    Full Text Available Molecular mimicry, defined as similar structures shared by molecules from dissimilar genes or proteins, is a general strategy used by pathogens to infect host cells. Severe acute respiratory syndrome (SARS is a new human respiratory infectious disease caused by SARS coronavirus (SARS-CoV. The spike (S protein of SARS-CoV plays an important role in the virus entry into a cell. In this study, eleven synthetic peptides from the S protein were selected based on its sequence homology with human proteins. Two of the peptides D07 (residues 927–937 and D08 (residues 942–951 were recognized by the sera of SARS patients. Murine hyperimmune sera against these peptides bound to proteins of human lung epithelial cells A549. Another peptide D10 (residues 490–502 stimulated A549 to proliferate and secrete IL-8. The present results suggest that the selected S protein regions, which share sequence homology with human proteins, may play important roles in SARS-CoV infection.

  16. Forest Height Inversion Using Dual-pol Polarimetric SAR Interferometry

    International Nuclear Information System (INIS)

    Polarimetric Synthetic Aperture Radar Interferometry (PolInSAR) has been extensively applied for forest parameter inversion over different frequencies and polarimetric conditions. So far, most research was based on full-pol SAR images with relatively small coverage. A spaceborne SAR system will have the potential for PolInSAR applications used for global forest monitoring. Spaceborne dual-pol SAR images usually have higher resolution and larger swath than full-pol mode. In this paper, forest height retrieval was attempted by PolInSAR from a L-band spaceborne dual-pol SAR pairs using HH and HV channels. The random volume over ground (RVoG) model was used to retrieve the height and the coherence optimization method was extended to the dual-pol PolInSAR, which makes use of polarimetry to enhance the quality of SAR interferograms. The three-stage process is also used in the dual-pol PolInSAR technique. Finally, the experimental test was performed for forest height estimation on the dual-pol L-band SAR data of the Saihanba forest acquired by the ALOS PALSAR sensor in 2009

  17. The outbreak pattern of the SARS cases in Asia

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhibin; SHENG Chengfa; MA Zufei; LI Dianmo

    2004-01-01

    The severe acute respiratory syndrome (SARS) caused tremendous damage to many Asia countries, especially China. The transmission process and outbreak pattern of SARS is still not well understood. This study aims to find a simple model to describe the outbreak pattern of SARS cases by using SARS case data commonly released by governments. The outbreak pattern of cumulative SARS cases is expected to be a logistic type because the infection will be slowed down due to the increasing control effort by people and/or due to depletion of susceptible individuals. The increase rate of SARS cases is expected to decrease with the cumulative SARS cases, as described by the traditional logistical model, which is widely used in population dynamic studies. The instantaneous rate of increases were significantly and negatively correlated with the cumulative SARS cases in mainland of China (including Beijing, Hebei, Tianjin, Shanxi, the Autonomous Region of Inner Mongolia) and Singapore. The basic reproduction number R0 in Asia ranged from 2.0 to 5.6 (except for Taiwan, China). The R0 of Hebei and Tianjinwere much higher than that of Singapore, Hongkong, Beijing, Shanxi, Inner Mongolia, indicating SARS virus might have originated differently or new mutations occurred during transmission. We demonstrated that the outbreaks of SARS in many regions of Asia were well described by the logistic model, and the control measures implemented by governments are effective. The maximum instantaneous rate of increase, basic reproductive number, and maximum cumulative SARS cases were also calculated by using the logistic model.

  18. Regulation of protein A synthesis by the sar and agr loci of Staphylococcus aureus.

    OpenAIRE

    Cheung, A L; Eberhardt, K.; Heinrichs, J H

    1997-01-01

    The synthesis of protein A in Staphylococcus aureus is regulated by global regulatory loci such as sar and agr. Phenotypic data indicate that both sar and agr suppress protein A synthesis; like agr, sar also regulates protein A production at the transcriptional level. To determine the genetic requirement of sar in protein A suppression, we transformed shuttle plasmids containing various sar fragments into a sar mutant. Our results indicated that the 560-bp sarA transcript, or, more probably, ...

  19. The first Sentinel-1 SAR image of a typhoon

    Institute of Scientific and Technical Information of China (English)

    LI Xiaofeng

    2015-01-01

    In this note, we present the first Sentinel-1 synthetic aperture radar (SAR) typhoon image acquired in the northwest Pacific on October 4, 2014. The eye shape and sea surface wind patterns associated with Typhoon Phanfone are clearly shown in the high-quality SAR image. SAR winds retrieval procedure was given but the actual wind estimates will only be available after the European Space Agency (ESA) releases the official calibration coefficients in order to accurately derive the SAR-measured normalized radar cross section. This study demonstrates the advantage of Sentinel-1 SAR with regards to imaging fine scale typhoon patterns on the sea surface beneath storm clouds. This paper also advocates the use of Sentinel-1 SAR data that is made freely and openly available worldwide for the first time in civilian SAR history.

  20. SAR Raw Data Generation for Complex Airport Scenes

    Directory of Open Access Journals (Sweden)

    Jia Li

    2014-10-01

    Full Text Available The method of generating the SAR raw data of complex airport scenes is studied in this paper. A formulation of the SAR raw signal model of airport scenes is given. Via generating the echoes from the background, aircrafts and buildings, respectively, the SAR raw data of the unified SAR imaging geometry is obtained from their vector additions. The multipath scattering and the shadowing between the background and different ground covers of standing airplanes and buildings are analyzed. Based on the scattering characteristics, coupling scattering models and SAR raw data models of different targets are given, respectively. A procedure is given to generate the SAR raw data of airport scenes. The SAR images from the simulated raw data demonstrate the validity of the proposed method.

  1. New challenges for a SAR toolbox

    International Nuclear Information System (INIS)

    High resolution multi-frequency synthetic aperture radar (SAR) imagery, available since early 2008, brings all weather capability and day/night operability in support of safeguards verification. Today, a combined approach of high resolution optical and radar imagery in monitoring exercise would enable looking at any area of interest on daily basis. One of the challenges is the co-registration of SAR images acquired with different acquisition mode and also with different optical images. We show in this paper the on-going research work to find a general co-register method and an automatic tool to detect changes. Before having an operational co-register tool, a method to find automatically tie points between SAR images acquired with different acquisition mode and with optical images has to be developed. Concerning an automatic change detection method we can conclude that the study of the Harmonic mean, Geometric mean and Arithmetic mean, enables several applications like change detection for SAR imagery. Thus, we developed the MAGMA (Method for Arithmetic and Geometric Means Analysis) change detection method. As shown in this paper, the MAGMA method improves the Maximum Likelihood techniques like GLRT, using Information-Theory concepts to detect changes between SAR amplitude images. The major improvement consists in a lower false detection rate, especially in low amplitude areas. The second improvement consists in a better location of the changes in clearly delimited areas, which enables precise interpretations. Results presented here reveal the potential of high resolution radar imagery for a baseline description of some sites, change detection based on repeat pass imagery acquisitions and site specific constraints in coherent change detection due to cover conditions. (A.C.)

  2. Analysis of Multipath Pixels in SAR Images

    Science.gov (United States)

    Zhao, J. W.; Wu, J. C.; Ding, X. L.; Zhang, L.; Hu, F. M.

    2016-06-01

    As the received radar signal is the sum of signal contributions overlaid in one single pixel regardless of the travel path, the multipath effect should be seriously tackled as the multiple bounce returns are added to direct scatter echoes which leads to ghost scatters. Most of the existing solution towards the multipath is to recover the signal propagation path. To facilitate the signal propagation simulation process, plenty of aspects such as sensor parameters, the geometry of the objects (shape, location, orientation, mutual position between adjacent buildings) and the physical parameters of the surface (roughness, correlation length, permittivity)which determine the strength of radar signal backscattered to the SAR sensor should be given in previous. However, it's not practical to obtain the highly detailed object model in unfamiliar area by field survey as it's a laborious work and time-consuming. In this paper, SAR imaging simulation based on RaySAR is conducted at first aiming at basic understanding of multipath effects and for further comparison. Besides of the pre-imaging simulation, the product of the after-imaging, which refers to radar images is also taken into consideration. Both Cosmo-SkyMed ascending and descending SAR images of Lupu Bridge in Shanghai are used for the experiment. As a result, the reflectivity map and signal distribution map of different bounce level are simulated and validated by 3D real model. The statistic indexes such as the phase stability, mean amplitude, amplitude dispersion, coherence and mean-sigma ratio in case of layover are analyzed with combination of the RaySAR output.

  3. Toxicity of cobalt-complexed cyanide to Oncorhynchus mykiss, Daphnia magna, and Ceriodaphnia dubia: Potentiation by ultraviolet radiation and attenuation by dissolved organic carbon and adaptive UV tolerance

    Science.gov (United States)

    Little, E.E.; Calfee, R.D.; Theodorakos, P.; Brown, Z.A.; Johnson, C.A.

    2007-01-01

    Background. Cobalt cyanide complexes often result when ore is treated with cyanide solutions to extract gold and other metals. These have recently been discovered in low but significant concentrations in effluents from gold leach operations. This study was conducted to determine the potential toxicity of cobalt-cyanide complexes to freshwater organisms and the extent to which ultraviolet radiation (UV) potentiates this toxicity. Tests were also conducted to determine if humic acids or if adaptation to UV influenced sensitivity to the cyanide complexes. Methods. Rainbow trout (Oncorhynchus mykiss), Daphnia magna, and Ceriodaphnia dubia were exposed to potassium hexacyanocobaltate in the presence and absence of UV radiation, in the presence and absence of humic acids. Cyano-cobalt exposures were also conducted with C. dubia from cultures adapted to elevated UV. Results. With an LC50 concentration of 0.38 mg/L, cyanocobalt was over a 1000 times more toxic to rainbow trout in the presence of UV at a low, environmentally relevant irradiance level (4 ??W/cm2 as UVB) than exposure to this compound in the absence of UV with an LC50 of 112.9 mg/L. Toxicity was immediately apparent, with mortality occurring within an hour of the onset of exposure at the highest concentration. Fish were unaffected by exposure to UV alone. Weak-acid dissociable cyanide concentrations were observed in irradiated aqueous solutions of cyanocobaltate within hours of UV exposure and persisted in the presence of UV for at least 96 hours, whereas negligible concentrations were observed in the absence of UV. The presence of humic acids significantly diminished cyanocobalt toxicity to D. magna and reduced mortality from UV exposure. Humic acids did not significantly influence survival among C. dubia. C. dubia from UV-adapted populations were less sensitive to metallocyanide compounds than organisms from unadapted populations. Conclusions. The results indicate that metallocyanide complexes may pose a

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

    Science.gov (United States)

    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.

  5. Spaceborne Polarimetric SAR Interferometry: Performance Analysis and Mission Concepts

    Directory of Open Access Journals (Sweden)

    Shane R. Cloude

    2005-12-01

    Full Text Available We investigate multichannel imaging radar systems employing coherent combinations of polarimetry and interferometry (Pol-InSAR. Such systems are well suited for the extraction of bio- and geophysical parameters by evaluating the combined scattering from surfaces and volumes. This combination leads to several important differences between the design of Pol-InSAR sensors and conventional single polarisation SAR interferometers. We first highlight these differences and then investigate the Pol-InSAR performance of two proposed spaceborne SAR systems (ALOS/PalSAR and TerraSAR-L operating in repeat-pass mode. For this, we introduce the novel concept of a phase tube which enables (1 a quantitative assessment of the Pol-InSAR performance, (2 a comparison between different sensor configurations, and (3 an optimization of the instrument settings for different Pol-InSAR applications. The phase tube may hence serve as an interface between system engineers and application-oriented scientists. The performance analysis reveals major limitations for even moderate levels of temporal decorrelation. Such deteriorations may be avoided in single-pass sensor configurations and we demonstrate the potential benefits from the use of future bi- and multistatic SAR interferometers.

  6. Federated query services provided by the Seamless SAR Archive project

    Science.gov (United States)

    Baker, S.; Bryson, G.; Buechler, B.; Meertens, C. M.; Crosby, C. J.; Fielding, E. J.; Nicoll, J.; Youn, C.; Baru, C.

    2013-12-01

    The NASA Advancing Collaborative Connections for Earth System Science (ACCESS) seamless synthetic aperture radar (SAR) archive (SSARA) project is a 2-year collaboration between UNAVCO, the Alaska Satellite Facility (ASF), the Jet Propulsion Laboratory (JPL), and OpenTopography at the San Diego Supercomputer Center (SDSC) to design and implement a seamless distributed access system for SAR data and derived data products (i.e. interferograms). A major milestone for the first year of the SSARA project was a unified application programming interface (API) for SAR data search and results at ASF and UNAVCO (WInSAR and EarthScope data archives) through the use of simple web services. A federated query service was developed using the unified APIs, providing users a single search interface for both archives (http://www.unavco.org/ws/brokered/ssara/sar/search). A command line client that utilizes this new service is provided as an open source utility for the community on GitHub (https://github.com/bakerunavco/SSARA). Further API development and enhancements added more InSAR specific keywords and quality control parameters (Doppler centroid, faraday rotation, InSAR stack size, and perpendicular baselines). To facilitate InSAR processing, the federated query service incorporated URLs for DEM (from OpenTopography) and tropospheric corrections (from the JPL OSCAR service) in addition to the URLs for SAR data. This federated query service will provide relevant QC metadata for selecting pairs of SAR data for InSAR processing and all the URLs necessary for interferogram generation. Interest from the international community has prompted an effort to incorporate other SAR data archives (the ESA Virtual Archive 4 and the DLR TerraSAR-X_SSC Geohazard Supersites and Natural Laboratories collections) into the federated query service which provide data for researchers outside the US and North America.

  7. How SARS Taught Me to Cook

    Institute of Scientific and Technical Information of China (English)

    GUAVALEE

    2003-01-01

    DURING the week-long May Day holiday I usually hold a party, or enjoy the good weather on outings with friends, but thanks to the SARS epidemic in Beijing this year, I stayed at home the entire May Day holiday. It was no problem finding something to do with my ample spare time, as I can surf the Internet for hours on end. My biggest headache was eating.Having dined in cafeterias and restaurants for the previous ten years or so, I had never learned to cook, but as SARS had begun to spread in Beijing in late April, the cafeteria in my work unit and most restaurants were closed for the holiday.

  8. Digital demodulator for wide bandwidth SAR

    DEFF Research Database (Denmark)

    Jørgensen, Jørn Hjelm

    2000-01-01

    A novel approach to the design of efficient digital quadrature demodulators for wide bandwidth SAR systems is described. Efficiency is obtained by setting the intermediate frequency to 1/4 the ADC sampling frequency. One channel is made filter-free by synchronizing the local oscillator with the...... output decimator. The filter required by the other channel is optimized through global search using the system level performance metrics integrated sidelobe level ratio (ISLR) and peak sidelobe level ratio (PSLR)....

  9. DEM Construction using DInSAR

    OpenAIRE

    Mangla, R.; Kumar, S

    2014-01-01

    A digital elevation model (DEM) is a 3D visualization of a terrain surface. It can be used in various analytical studies such as topographic feature extraction, hydrology, geomorphology and landslides analysis etc. Uttrakhand region is affected with landslides, earthquake and flash flood phenomenon. Hence this study was focused on DEM generation using Differential SAR Interferometry (DINSAR) on ALOS PALSAR dataset. Two Pass DINSAR technique involves one interferometric pair in additi...

  10. Multiplier-free filters for wideband SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Christensen, Erik Lintz

    2001-01-01

    This paper derives a set of parameters to be optimized when designing filters for digital demodulation and range prefiltering in SAR systems. Aiming at an implementation in field programmable gate arrays (FPGAs), an approach for the design of multiplier-free filters is outlined. Design results are...... presented in terms of filter complexity and performance. One filter has been coded in VHDL and preliminary results indicate that the filter can meet a 2 GHz input sample rate....

  11. Adaptive Filter in SAR Interferometry Derived DEM

    Institute of Scientific and Technical Information of China (English)

    XU Caijun; WANG Hua; WANG Jianglin; GE Linlin

    2005-01-01

    In this paper, the performance of median filter, elevation dependent adaptive sigma median filter, and directionally dependent adaptive sigma median filter are tested on both InSAR Tandem DEM and simulated high-level noisy DEM. Through the comparison, the directionally dependent adaptive sigma median filter is proved to be the most effective one not only in the noise removing but also in the boundary preserve.

  12. Potentials and Limitations of MEO SAR

    OpenAIRE

    Matar, Jalal; López Dekker, Francisco; Krieger, Gerhard

    2016-01-01

    This paper discusses the various aspects of Synthetic Aperture Radar (SAR) missions in Medium Earth Orbits (MEO). It covers the design of suitable orbits and their corresponding coverage, with emphasis on repeat ones. Furthermore, it analyses the changes in performance as altitude increases, while addressing the potentials and limitations of high orbits. Throughout the paper one interesting orbit, repeating its ground track every 3 days and providing near-global coverage, is studied.

  13. Molecular phylogeny of coronaviruses including human SARS-CoV

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Phylogenetic tree of coronaviruses (CoVs) including the human SARS-associated virus is reconstructed from complete genomes by using our newly developed K- string composition approach. The relation of the human SARS-CoV to other coronaviruses, i.e. the rooting of the tree is suggested by choosing an appropriate outgroup. SARS-CoV makes a separate group closer but still distant from G2 (CoVs in mammalian host). The relation between different isolates of the human SARS virus is inferred by first constructing an ultrametric distance matrix from counting sequence variations in the genomes. The resulting tree is consistent with clinic relations between the SARS-CoV isolates. In addition to a larger variety of coronavirus genomes these results provide phylogenetic knowledge based on independent novel methodology as compared to recent phylogenetic studies on SARS-CoV.

  14. A 3-D SAR approach to IFSAR processing

    Energy Technology Data Exchange (ETDEWEB)

    DOERRY,ARMIN W.; BICKEL,DOUGLAS L.

    2000-03-01

    Interferometric SAR (IFSAR) can be shown to be a special case of 3-D SAR image formation. In fact, traditional IFSAR processing results in the equivalent of merely a super-resolved, under-sampled, 3-D SAR image. However, when approached as a 3-D SAR problem, a number of IFSAR properties and anomalies are easily explained. For example, IFSAR decorrelation with height is merely ordinary migration in 3-D SAR. Consequently, treating IFSAR as a 3-D SAR problem allows insight and development of proper motion compensation techniques and image formation operations to facilitate optimal height estimation. Furthermore, multiple antenna phase centers and baselines are easily incorporated into this formulation, providing essentially a sparse array in the elevation dimension. This paper shows the Polar Format image formation algorithm extended to 3 dimensions, and then proceeds to apply it to the IFSAR collection geometry. This suggests a more optimal reordering of the traditional IFSAR processing steps.

  15. SAR Image Segmentation Using Morphological Attribute Profiles

    Science.gov (United States)

    Boldt, M.; Thiele, A.; Schulz, K.; Hinz, S.

    2014-08-01

    In the last years, the spatial resolution of remote sensing sensors and imagery has continuously improved. Focusing on spaceborne Synthetic Aperture Radar (SAR) sensors, the satellites of the current generation (TerraSAR-X, COSMO-SykMed) are able to acquire images with sub-meter resolution. Indeed, high resolution imagery is visually much better interpretable, but most of the established pixel-based analysis methods have become more or less impracticable since, in high resolution images, self-sufficient objects (vehicle, building) are represented by a large number of pixels. Methods dealing with Object-Based Image Analysis (OBIA) provide help. Objects (segments) are groupings of pixels resulting from image segmentation algorithms based on homogeneity criteria. The image set is represented by image segments, which allows the development of rule-based analysis schemes. For example, segments can be described or categorized by their local neighborhood in a context-based manner. In this paper, a novel method for the segmentation of high resolution SAR images is presented. It is based on the calculation of morphological differential attribute profiles (DAP) which are analyzed pixel-wise in a region growing procedure. The method distinguishes between heterogeneous and homogeneous image content and delivers a precise segmentation result.

  16. SARS epidemical forecast research in mathematical model

    Institute of Scientific and Technical Information of China (English)

    DING Guanghong; LIU Chang; GONG Jianqiu; WANG Ling; CHENG Ke; ZHANG Di

    2004-01-01

    The SIJR model, simplified from the SEIJR model, is adopted to analyze the important parameters of the model of SARS epidemic such as the transmission rate, basic reproductive number. And some important parameters are obtained such as the transmission rate by applying this model to analyzing the situation in Hong Kong, Singapore and Canada at the outbreak of SARS. Then forecast of the transmission of SARS is drawn out here by the adjustment of parameters (such as quarantined rate) in the model. It is obvious that inflexion lies on the crunode of the graph, which indicates the big difference in transmission characteristics between the epidemic under control and not under control. This model can also be used in the comparison of the control effectiveness among different regions. The results from this model match well with the actual data in Hong Kong, Singapore and Canada and as a by-product, the index of the effectiveness of control in the later period can be acquired. It offers some quantitative indexes, which may help the further research in epidemic diseases.

  17. Death of a SARS case from secondary aspergillus infection

    Institute of Scientific and Technical Information of China (English)

    王慧君; 丁彦青; 徐军; 李欣; 李学锋; 杨磊; 张文丽; 耿健; 申洪; 蔡俊杰; 康伟; 吴正容; 赵菲; 钟南山

    2004-01-01

    @@ Severe acute respiratory syndrome (SARS) is an acute infectious disease which has been found to spread mainly via respiration. The first case was idnetified in Guangdong, southem China in November 2002. This disease has resulted in a severe epidemic outbreak in 27 countries and regions. In order to investigate the etiology and clinicopathologic characteristics of SARS, we reported here a patient with SARS who died of aspergillosis after prolonged treatment with corticosteroids.

  18. Vibration and rotation in millimeter-wave SAR

    OpenAIRE

    Rüegg, M; Meier, E; D. Nüesch

    2007-01-01

    Synthetic aperture radar (SAR) provides high-resolution images of static ground scenes, whereas processing of data containing ground object motion results in varying focusing effects. Special cases of such motion are vibration and rotation, which are closely related to each other. Their patterns may be distinctly recognizable in focused SAR intensity images as well as in a time–frequency analysis. Millimeter-wave (mmW) SAR is well suited to image vibration because its wavelength is close to t...

  19. Quick determination of refraction points for GPR SAR imaging

    Science.gov (United States)

    Wang, Guangli; Wu, Renbiao; Zhang, Minxin

    2005-06-01

    Synthetic aperture radar (SAR) imaging with ground penetrating radar (GPR) has proven to be an effective nondestructive testing tool. Most GPR SAR imaging algorithms are based on delay-and-sum beamforming, which relies heavily on the travel path calculation in the media where targets are buried. In this paper, a computationally very efficient and convergence guaranteed algorithm is proposed for determining refraction points between boundaries of multiple planar media, which is vital to GPR SAR imaging.

  20. An Orthogonal Waveform for Fully Polarimetric MIMO-SAR

    OpenAIRE

    Rommel, Tobias; Younis, Marwan; Krieger, Gerhard

    2014-01-01

    Synthetic aperture radar (SAR) with multiple transmit and receive channels (MIMO-SAR) has a higher flexibility and an improved efficiency compared to a conventional SAR system with a single channel. The multiple receive channels can be used, among other things, to increase the swath width at constant azimuth resolution or to suppress spatial interferences. However, multiple transmit channels, which transmit simultaneously in the same frequency band provide currently a challenge. Therefore, in...

  1. An Orthogonal Waveform for MIMO-SAR Applications

    OpenAIRE

    Rommel, Tobias; Huber, Sigurd; Patyuchenko, Anton; Laskowski, Piotr; Younis, Marwan; Krieger, Gerhard

    2014-01-01

    Synthetic aperture radar (SAR) with multiple transmit and receive channels (MIMO-SAR) has a higher flexibility and an improved efficiency compared to a conventional SAR system with a single channel. The multiple receive channels can be used, among other things, to increase the swath width at constant azimuth resolution or to suppress spatial interferences. However, multiple transmit channels, which transmit simultaneously in the same frequency band provide currently a challenge. The generatio...

  2. RESEARCH ON IMAGE TRANSLATION BETWEEN SAR AND OPTICAL IMAGERY

    OpenAIRE

    Fu; Zhang,

    2012-01-01

    Compare to optical sensors, Synthetic Aperture Radar (SAR) sensors can work at all time and under all weather conditions. However, SAR images are less intuitive and more difficult to understand. To complement advantages of optical and SAR sensors, a technique of image translation is put forward. Firstly, the concept named as remote sensing image translation is presented, and a set of technology thinking for multi-source remote sensing image translation is also given. Image understand...

  3. RFI Suppression in Ultrawideband SAR Using an Adaptive Line Enhancer

    OpenAIRE

    Vu, Viet Thuy; Sjögren, Thomas; Pettersson, Mats; Håkansson, Lars; Gustavsson, Anders; Ulander, Lars

    2010-01-01

    In this letter, we propose an approach to suppress radio-frequency interference (RFI) in ultrawideband (UWB) low-frequency synthetic aperture radar (SAR). According to the proposal, RFI is suppressed by using an adaptive line enhancer controlled by the normalized least mean square algorithm. The approach is tested successfully on real UWB low-frequency SAR data. In order to keep the computational burden down, possible ways to integrate the RFI suppression approach into SAR imaging algorithms ...

  4. Forming rotated SAR images by real-time motion compensation.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2012-12-01

    Proper waveform parameter selection allows collecting Synthetic Aperture Radar (SAR) phase history data on a rotated grid in the Fourier Space of the scene being imaged. Subsequent image formation preserves the rotated geometry to allow SAR images to be formed at arbitrary rotation angles without the use of computationally expensive interpolation or resampling operations. This should be useful where control of image orientation is desired such as generating squinted stripmaps and VideoSAR applications, among others.

  5. Prototype Theory Based Feature Representation for PolSAR Images

    OpenAIRE

    Huang Xiaojing; Yang Xiangli; Huang Pingping; Yang Wen

    2016-01-01

    This study presents a new feature representation approach for Polarimetric Synthetic Aperture Radar (PolSAR) image based on prototype theory. First, multiple prototype sets are generated using prototype theory. Then, regularized logistic regression is used to predict similarities between a test sample and each prototype set. Finally, the PolSAR image feature representation is obtained by ensemble projection. Experimental results of an unsupervised classification of PolSAR images show that our...

  6. Risk Factors for SARS-Related Deaths in 2003, Beijing

    Institute of Scientific and Technical Information of China (English)

    MIN LIU; WAN-NIAN LIANG; QI CHEN; XUE-QIN XIE; JIANG WU; XIONG HE; ZE-JUN LIU

    2006-01-01

    Objective To study the potential risk factors for severe acute respiratory syndromes (SARS)-related deaths in Beijing. Methods Epidemiological data were collected among the confirmed SARS patients officially reported by Beijing Centers for Disease Control and Prevention (BCDC), and information was also supplemented by a follow-up case survey. Chi-square test and multivariate stepwise logistic regression analysis were performed. Results Old age (over 60 years) was found to be significantly associated with SARS-related deaths in the univariate analysis. Also, history of contacting SARS patients within 2 weeks prior to the onset of illness, health occupation, and inferior hospital ranking as well as longer interval of clinic consulting (longer than 1 day) were the risk factors for SARS-related deaths. Multivariate stepwise logistic regression analysis found four risk factors for SARS-related deaths. Conclusion Old age (over 60 years) is the major risk factor for SARS-related deaths.Moreover, hospital health workers, the designated hospitals for SARS clinical services and the interval of consulting doctors (less than 1 day) are protective factors for surviving from SARS.

  7. Applications of SAR Interferometry in Earth and Environmental Science Research

    Directory of Open Access Journals (Sweden)

    Xiaobing Zhou

    2009-03-01

    Full Text Available This paper provides a review of the progress in regard to the InSAR remote sensing technique and its applications in earth and environmental sciences, especially in the past decade. Basic principles, factors, limits, InSAR sensors, available software packages for the generation of InSAR interferograms were summarized to support future applications. Emphasis was placed on the applications of InSAR in seismology, volcanology, land subsidence/uplift, landslide, glaciology, hydrology, and forestry sciences. It ends with a discussion of future research directions.

  8. Applications of SAR Interferometry in Earth and Environmental Science Research.

    Science.gov (United States)

    Zhou, Xiaobing; Chang, Ni-Bin; Li, Shusun

    2009-01-01

    This paper provides a review of the progress in regard to the InSAR remote sensing technique and its applications in earth and environmental sciences, especially in the past decade. Basic principles, factors, limits, InSAR sensors, available software packages for the generation of InSAR interferograms were summarized to support future applications. Emphasis was placed on the applications of InSAR in seismology, volcanology, land subsidence/uplift, landslide, glaciology, hydrology, and forestry sciences. It ends with a discussion of future research directions. PMID:22573992

  9. Research work on SARS has to be strengthened in China

    Institute of Scientific and Technical Information of China (English)

    王辰

    2003-01-01

    @@ In the spring of 2003, the medical community within China experienced grim challenges when they were confronted with an unexpected disease now referred to as severe acute respiratory syndrome (SARS). During the fight of the bloody war against SARS, Chinese healthcare workers risked of their own lives and dealt with numerous clinical treatments. However, they never forgot their mission to invigorate our nation through science and technology. They actively conducted scientific research on SARS and received preliminary achievements in a very short time, these achievements have become useful tools in the prevention and treatment against SARS.

  10. SAR11 bacteria linked to ocean anoxia and nitrogen loss

    DEFF Research Database (Denmark)

    Tsementzi, Despina; Wu, Jieying; Deutsch, Samuel;

    2016-01-01

    Bacteria of the SAR11 clade constitute up to one half of all microbial cells in the oxygen-rich surface ocean. SAR11 bacteria are also abundant in oxygen minimum zones (OMZs), where oxygen falls below detection and anaerobic microbes have vital roles in converting bioavailable nitrogen to N2 gas....... Anaerobic metabolism has not yet been observed in SAR11, and it remains unknown how these bacteria contribute to OMZ biogeochemical cycling. Here, genomic analysis of single cells from the world’s largest OMZ revealed previously uncharacterized SAR11 lineages with adaptations for life without oxygen...

  11. Epipolar geometry comparison of SAR and optical camera

    Science.gov (United States)

    Li, Dong; Zhang, Yunhua

    2016-03-01

    In computer vision, optical camera is often used as the eyes of computer. If we replace camera with synthetic aperture radar (SAR), we will then enter a microwave vision of the world. This paper gives a comparison of SAR imaging and camera imaging from the viewpoint of epipolar geometry. The imaging model and epipolar geometry of the two sensors are analyzed in detail. Their difference is illustrated, and their unification is particularly demonstrated. We hope these may benefit researchers in field of computer vision or SAR image processing to construct a computer SAR vision, which is dedicated to compensate and improve human vision by electromagnetically perceiving and understanding the images.

  12. Comparing satellite SAR and wind farm wake models

    OpenAIRE

    Hasager, Charlotte Bay; Vincent, P.; Husson, R.; Mouche, Alexis; Badger, Merete; Pena Diaz, Alfredo; Volker, Patrick; Badger, Jake; Di Bella, Alessandro; Palomares, A.; Cantero, E.; Correia, P. M. F.

    2015-01-01

    The aim of the paper is to present offshore wind farm wake observed from satellite Synthetic Aperture Radar (SAR) wind fields from RADARSAT-1/-2 and Envisat and to compare these wakes qualitatively to wind farm wake model results. From some satellite SAR wind maps very long wakes are observed. These extend several tens of kilometres downwind e.g. 70 km. Other SAR wind maps show near-field fine scale details of wake behind rows of turbines. The satellite SAR wind farm wake cases are modelled b...

  13. InSAR Scientific Computing Environment

    Science.gov (United States)

    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

  14. Hydrodynamics of the groundwater-fed Sian Ka'an Wetlands, Mexico, From InSAR and SAR Data

    DEFF Research Database (Denmark)

    Gondwe, Bibi Ruth Neuman; Hong, S.; Wdowinski, S.;

    2008-01-01

    The 5300 km2 pristine Sian Ka'an wetland in Mexico is fed entirely by groundwater from the karst aquifer of the Yucatan Peninsula. The area is undeveloped and hence difficult to access. The inflow through underground rivers and karst structures is hard to observe resulting in difficulties...... to understand, quantify and predict the wetland dynamics. Remotely sensed Interferometric Synthetic Aperture Radar (InSAR) and Synthetic Aperture Radar (SAR) data offer new opportunities to get hydrodynamic information, which is useful for wetland management. InSAR data produces temporal phase......-changes of the backscattered radar signal, which can be related to the water level changes in vegetated wetlands. SAR data reveals information of surface properties such as the degree of flooding through the amplitude of the backscattered signal. We used RADARSAT-1 InSAR and SAR data to form 36 interferograms and 13 flooding...

  15. Kinetics of Severe Acute Respiratory Syndrome (SARS) Coronavirus-Specific Antibodies in 271 Laboratory-Confirmed Cases of SARS

    OpenAIRE

    He, Zhongping; Dong, Qingming; Zhuang, Hui; Song, Shujing; Peng, Guoai; Luo, Guangxiang; Dwyer, Dominic E.

    2004-01-01

    The sensitivities and specificities of an immunofluorescence assay and an enzyme immunoassay for detection of antibodies specific for severe acute respiratory syndrome coronavirus (SARS-CoV) were compared for 148 laboratory-confirmed SARS cases. The appearance and persistence of SARS-CoV-specific antibodies were assessed, with immunoglobulin G detected in 59% of samples collected within 14 days and persisting for 60 to 95 days after the onset of illness.

  16. Impact of the Regulators SigB, Rot, SarA and sarS on the Toxic Shock Tst Promoter and TSST-1 Expression in Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Diego O Andrey

    Full Text Available Staphylococcus aureus is an important pathogen manifesting virulence through diverse disease forms, ranging from acute skin infections to life-threatening bacteremia or systemic toxic shock syndromes. In the latter case, the prototypical superantigen is TSST-1 (Toxic Shock Syndrome Toxin 1, encoded by tst(H, and carried on a mobile genetic element that is not present in all S. aureus strains. Transcriptional regulation of tst is only partially understood. In this study, we dissected the role of sarA, sarS (sarH1, RNAIII, rot, and the alternative stress sigma factor sigB (σB. By examining tst promoter regulation predominantly in the context of its native sequence within the SaPI1 pathogenicity island of strain RN4282, we discovered that σB emerged as a particularly important tst regulator. We did not detect a consensus σB site within the tst promoter, and thus the effect of σB is likely indirect. We found that σB strongly repressed the expression of the toxin via at least two distinct regulatory pathways dependent upon sarA and agr. Furthermore rot, a member of SarA family, was shown to repress tst expression when overexpressed, although its deletion had no consistent measurable effect. We could not find any detectable effect of sarS, either by deletion or overexpression, suggesting that this regulator plays a minimal role in TSST-1 expression except when combined with disruption of sarA. Collectively, our results extend our understanding of complex multifactorial regulation of tst, revealing several layers of negative regulation. In addition to environmental stimuli thought to impact TSST-1 production, these findings support a model whereby sporadic mutation in a few key negative regulators can profoundly affect and enhance TSST-1 expression.

  17. Impact of the Regulators SigB, Rot, SarA and sarS on the Toxic Shock Tst Promoter and TSST-1 Expression in Staphylococcus aureus.

    Science.gov (United States)

    Andrey, Diego O; Jousselin, Ambre; Villanueva, Maite; Renzoni, Adriana; Monod, Antoinette; Barras, Christine; Rodriguez, Natalia; Kelley, William L

    2015-01-01

    Staphylococcus aureus is an important pathogen manifesting virulence through diverse disease forms, ranging from acute skin infections to life-threatening bacteremia or systemic toxic shock syndromes. In the latter case, the prototypical superantigen is TSST-1 (Toxic Shock Syndrome Toxin 1), encoded by tst(H), and carried on a mobile genetic element that is not present in all S. aureus strains. Transcriptional regulation of tst is only partially understood. In this study, we dissected the role of sarA, sarS (sarH1), RNAIII, rot, and the alternative stress sigma factor sigB (σB). By examining tst promoter regulation predominantly in the context of its native sequence within the SaPI1 pathogenicity island of strain RN4282, we discovered that σB emerged as a particularly important tst regulator. We did not detect a consensus σB site within the tst promoter, and thus the effect of σB is likely indirect. We found that σB strongly repressed the expression of the toxin via at least two distinct regulatory pathways dependent upon sarA and agr. Furthermore rot, a member of SarA family, was shown to repress tst expression when overexpressed, although its deletion had no consistent measurable effect. We could not find any detectable effect of sarS, either by deletion or overexpression, suggesting that this regulator plays a minimal role in TSST-1 expression except when combined with disruption of sarA. Collectively, our results extend our understanding of complex multifactorial regulation of tst, revealing several layers of negative regulation. In addition to environmental stimuli thought to impact TSST-1 production, these findings support a model whereby sporadic mutation in a few key negative regulators can profoundly affect and enhance TSST-1 expression. PMID:26275216

  18. SARS treatment: experience from a team in Guangdong, China

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    @@ The epidemic of SARS in Guangdong province of China is beginning to be restrained. In May 2003, Dr. Zhong Nanshan, head of the Guangzhou Institute of Respiratory Disease, presented at a training course in Beijing for medical personnel. Some important issues have been addressed based on the experience concluded during their combating with SARS in Guangdong.

  19. Immunological Responses against SARS-Coronavirus Infection in Humans

    Institute of Scientific and Technical Information of China (English)

    Xiaojun Xu; Xiao-Ming Gao

    2004-01-01

    Since the outbreak of a SARS epidemic last year, significant advances have been made on our understanding of the mechanisms of interaction between the SARS coronavirus (CoV) and the immune system. Strong humoral responses have been found in most patients following SARS-CoV infection, with high titers of neutralizing Abspresent in their convalescent sera. The nucleocapsid (N) and spike (S) proteins of SARS-CoV appear to be the dominant antigens recognized by serum Abs. CD4+ T cell responses against the N protein have been observed in SARS patients and an HLA-A2-restricted cytotoxic T lymphocyte epitope in the S protein has been identified.It is likely that the immune responses induced by SARS-CoV infection could also cause pathological damage to the host, especially in the case of proinflammatory cytokines. There is also evidence suggesting that SARS-CoV might be able to directly invade cells of the immune system. Our understanding on the interaction between SARS-CoV, the immune system and local tissues is essential to future diagnosis, control and treatment of this very contagious disease.

  20. An Adaptive Ship Detection Scheme for Spaceborne SAR Imagery.

    Science.gov (United States)

    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

  1. Mapping mountain meadow with high resolution and polarimetric SAR data

    International Nuclear Information System (INIS)

    This paper presents a method to map the large grassland in the eastern margin of the Tibetan Plateau with the high resolution polarimetric SAR (PolSAR) imagery. When PolSAR imagery is used for land cover classification, the brightness of a SAR image is affected by topography due to varying projection between ground and image coordinates. The objective of this paper is twofold: (1) we first extend the theory of SAR terrain correction to the polarimetric case, to utilize the entire available polarimetric signature, where correction is performed explicitly based on a matrix format like covariance matrix. (2) Next, the orthoectified PolSAR is applied to classify mountain meadow and investigate the potential of PolSAR in mapping grassland. In this paper, the gamma naught radiometric correction estimates the local illuminated area at each grid point in the radar geometry. Then, each element of the coherency matrix is divided by the local area to produce a polarimetric product. Secondly, the impact of radiometric correction upon classification accuracy is investigated. A supervised classification is performed on the orthorectified Radarsat-2 PolSAR to map the spatial distribution of meadow and evaluate monitoring capabilities of mountain meadow

  2. Ocean Surface Wind Speed of Hurricane Helene Observed by SAR

    DEFF Research Database (Denmark)

    Xu, Qing; Cheng, Yongcun; Li, Xiaofeng;

    2011-01-01

    The hurricanes can be detected by many remote sensors, but synthetic aperture radar (SAR) can yield high-resolution (sub-kilometer) and low-level wind information that cannot be seen below the cloud by other sensors. In this paper, an assessment of SAR capability of monitoring high-resolution hur......The hurricanes can be detected by many remote sensors, but synthetic aperture radar (SAR) can yield high-resolution (sub-kilometer) and low-level wind information that cannot be seen below the cloud by other sensors. In this paper, an assessment of SAR capability of monitoring high......-resolution hurricane was conducted. A case study was carried out to retrieve ocean surface wind field from C-band RADARSAT-1 SAR image which captured the structure of hurricane Helene over the Atlantic Ocean on 20 September, 2006. With wind direction from the outputs of U.S. Navy Operational Global Atmospheric...... CIWRAP models have been tested to extract wind speed from SAR data. The SAR retrieved ocean surface winds were compared to the aircraft wind speed observations from stepped frequency microwave radiometer (SFMR). The results show the capability of hurricane wind monitoring by SAR....

  3. Fully polarimetric data from the ARL RailSAR

    Science.gov (United States)

    Ranney, Kenneth; Kirose, Getachew; Phelan, Brian; Sherbondy, Kelly

    2016-05-01

    The U.S. Army Research Laboratory (ARL) has recently upgraded the indoor, rail-mounted synthetic aperture radar (SAR) system, RailSAR, to enable collection of large amounts of low-frequency, ultrawideband (UWB) data. Our intent is to provide a research tool that is capable of emulating airborne SAR configuration and associated data collection geometries against surrogate explosive hazard threat deployments. By having such a capability, ARL's facility will afford a more rapid response to the ever changing improvised characteristics associated with explosive hazards today and in the future. Therefore, upgrades to this RailSAR tool to improve functionality and performance are needed to meet the potential rapid response assessments to be carried out. The new, lighter RailSAR cart puts less strain on the radar positioning hardware and allows the system to move smoothly along a specified portion of the rail. In previous papers, we have presented co-polarized SAR data collected using the ARL RailSAR. Recently, however, researchers at ARL have leveraged this asset to collect polarimetric data against multiple targets. This paper presents the SAR imagery resulting from these experiments and documents characteristics of certain target signatures that should be of interest to developers of automatic target detection (ATD) algorithms.

  4. Polarimetric SAR interferometry applied to land ice: modeling

    DEFF Research Database (Denmark)

    Dall, Jørgen; Papathanassiou, Konstantinos; Skriver, Henning

    2004-01-01

    This paper introduces a few simple scattering models intended for the application of polarimetric SAR interfer-ometry to land ice. The principal aim is to eliminate the penetration bias hampering ice sheet elevation maps generated with single-channel SAR interferometry. The polarimetric coherent...

  5. Moving Ship SAR Imaging Based on Parameter Estimation

    OpenAIRE

    Yun Yajiao; Qi Xiangyang; Li Ning

    2016-01-01

    The Doppler parameters of moving targets affect the conventional Synthetic Aperture Radar (SAR) imaging. In this study, the relation between the motion and Doppler parameters is established. With improved popular technology, a set of moving ship SAR imaging processes is proposed to obtain a focused and rightlocated image. Simulations and experimental data are used to verify the method.

  6. Cloaked similarity between HIV-1 and SARS-CoV suggests an anti-SARS strategy

    Directory of Open Access Journals (Sweden)

    Kliger Yossef

    2003-09-01

    Full Text Available Abstract Background Severe acute respiratory syndrome (SARS is a febrile respiratory illness. The disease has been etiologically linked to a novel coronavirus that has been named the SARS-associated coronavirus (SARS-CoV, whose genome was recently sequenced. Since it is a member of the Coronaviridae, its spike protein (S2 is believed to play a central role in viral entry by facilitating fusion between the viral and host cell membranes. The protein responsible for viral-induced membrane fusion of HIV-1 (gp41 differs in length, and has no sequence homology with S2. Results Sequence analysis reveals that the two viral proteins share the sequence motifs that construct their active conformation. These include (1 an N-terminal leucine/isoleucine zipper-like sequence, and (2 a C-terminal heptad repeat located upstream of (3 an aromatic residue-rich region juxtaposed to the (4 transmembrane segment. Conclusions This study points to a similar mode of action for the two viral proteins, suggesting that anti-viral strategy that targets the viral-induced membrane fusion step can be adopted from HIV-1 to SARS-CoV. Recently the FDA approved Enfuvirtide, a synthetic peptide corresponding to the C-terminal heptad repeat of HIV-1 gp41, as an anti-AIDS agent. Enfuvirtide and C34, another anti HIV-1 peptide, exert their inhibitory activity by binding to a leucine/isoleucine zipper-like sequence in gp41, thus inhibiting a conformational change of gp41 required for its activation. We suggest that peptides corresponding to the C-terminal heptad repeat of the S2 protein may serve as inhibitors for SARS-CoV entry.

  7. Permanent scatterer InSAR processing: Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Dehls, John F. [Geological Survey of Norway, Trondheim (Norway)

    2006-04-15

    It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of

  8. sar Aira y el exotismo

    Directory of Open Access Journals (Sweden)

    Ricardo Gutiérrez-Mouat

    2013-07-01

    Full Text Available The present paper analyses one of the less commonly studied aspects of the poetics of César Aira: exoticism, which in Aira stems from the unstable and paradoxical place proper of a post-modern writer from the Rio de la Plata facing traditional (and European representations of exoticism in a period of cultural globalisation. The paper examines such a paradox and concludes that Aira’s exoticism is manifest in the ethnographic simulation and in certain thoughts on the de-familiarisation of the mother tongue.

  9. Salt Kinematics and InSAR

    Science.gov (United States)

    Aftabi, Pedarm; Talbot, hristopher; Fielding, Eric

    2005-01-01

    As part of a long-term attempt to learn how the climatic and tectonic signal interact to shape a steady state mountain monitored displacement of a markers in SE termination and also near the summit of a small viscous salt fountain extruding onto the Central plateau of Iran. The marker displacements relate to the first InSAR interferograms of salt extrusion (980913 to 990620) calculated Earth tides, winds, air pressures and temperatures. In the first documented staking exercise, hammered wooden stakes vertically through the surgical marl (c. 1 Ocm deep) onto the top of crystalline salt. These stakes installed in an irregular array elongate E-W along the c.50 m high cliff marking the effective SE terminus of the glacier at Qum Kuh(Centra1 Iran) ,just to the E of a NE trending river cliff about 40 m high. We merely measured the distances between pairs of stakes with known azimuth about 2 m apart to calculate sub horizontal strain in a small part of Qum Kuh. Stakes moved and micro strains for up to 46 pairs of stakes (p strain= ((lengthl-length2)/1engthl) x 10-1) was calculated for each seven stake epochs and plotted against their azimuth on simplified array maps. The data fit well the sine curves cxpected of the maximum and minimum strain ellipses. The first documented stakes located on the SE where the InSAR image show -1 1 to 0 mm pink to purple, 0 to lOmm purple to blue, and show high activity of salt in low activity area of the InSAR image (980913 to 990620).Short term micro strains of stake tie lines record anisotropic expansions due to heating and contraction due to cooling. All epochs changed between 7 to 1 17 days (990928 to000 1 16), showed 200 to 400 micro strain lengthening and shortening. The contraction and extension existed in each epoch, but the final strain was extension in E-W in Epoch land 6, contraction in E-W direction during epochs 2-3-4-5 and 7. The second pair of stakes hammered about 20 cm deep into the deep soils(more than 1 m) , near summit

  10. Permanent scatterer InSAR processing: Forsmark

    International Nuclear Information System (INIS)

    It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km2. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of errors

  11. Two dimensional estimates from ocean SAR images

    Directory of Open Access Journals (Sweden)

    J. M. Le Caillec

    1996-01-01

    Full Text Available Synthetic Aperture Radar (SAR images of the ocean yield a lot of information on the sea-state surface providing that the mapping process between the surface and the image is clearly defined. However it is well known that SAR images exhibit non-gaussian statistics and that the motion of the scatterers on the surface, while the image is being formed, may yield to nonlinearities. The detection and quantification of these nonlinearities are made possible by using Higher Order Spectra (HOS methods and more specifically, bispectrum estimation. The development of the latter method allowed us to find phase relations between different parts of the image and to recognise their level of coupling, i.e. if and how waves of different wavelengths interacted nonlinearly. This information is quite important as the usual models assume strong nonlinearities when the waves are propagating in the azimuthal direction (i.e. along the satellite track and almost no nonlinearities when propagating in the range direction. In this paper, the mapping of the ocean surface to the SAR image is reinterpreted and a specific model (i.e. a Second Order Volterra Model is introduced. The nonlinearities are thus explained as either produced by a nonlinear system or due to waves propagating into selected directions (azimuth or range and interacting during image formation. It is shown that quadratic nonlinearities occur for waves propagating near the range direction while for those travelling in the azimuthal direction the nonlinearities, when present, are mostly due to wave interactions but are almost completely removed by the filtering effect coming from the surface motion itself (azimuth cut-off. An inherent quadratic interaction filtering (azimuth high pass filter is also present. But some other effects, apparently nonlinear, are not detected with the methods described here, meaning that either the usual relation developed for the Ocean-to-SAR transform is somewhat incomplete

  12. Identification of an epitope of SARS-coronavirus nucleocapsid protein

    Institute of Scientific and Technical Information of China (English)

    YING LIN; JIN WANG; HONG XIA WANG; HUA LIANG JIANG; JIAN HUA SHEN; YOU HUA XIE; YUAN WANG; GANG PEI; BEI FEN SHEN; JIA RUI WU; BING SUN; XU SHEN; RUI FU YANG; YI XUE LI; YONG YONG JI; YOU YU HE; MUDE SHI; WEI LU; TIE LIU SHI

    2003-01-01

    The nucleocapsid (N) protein of severe acute respiratory syndrome-coronavirus (SARS-CoV) is a majorvirion structural protein. In this study, two epitopes (N1 and N2) of the N protein of SARS-CoV werepredicted by bioinformatics analysis. After immunization with two peptides, the peptides-specific antibodieswere isolated from the immunized rabbits. The further experiments demonstrated that N1 peptide-inducedpolyclonal antibodies had a high affinity to bind to E. coli expressed N protein of SARS-CoV. Furthermore, itwas confirmed that N1 peptide-specific IgG antibodies were detectable in the sera of severe acute respiratorysyndrome (SARS) patients. The results indicated that an epitope of the N protein has been identified andN protein specific Abs were produced by peptide immunization, which will be useful for the study of SARS-CoV.

  13. INVENTORY OF IRRIGATED RICE ECOSYSTEM USING POLARIMETRIC SAR DATA

    Directory of Open Access Journals (Sweden)

    P. Srikanth

    2012-08-01

    Full Text Available An attempt has been made in the current study to assess the potential of polarimetric SAR data for inventory of kharif rice and the major competing crop like cotton. In the process, physical process of the scattering mechanisms occurring in rice and cotton crops at different phonological stages was studied through the use of temporal Radarsat 2 Fine quadpol SAR data. The temporal dynamics of the volume, double and odd bounce, entropy, anisotropy, alpha parameters and polarimertic signatures, classification through isodata clustering and Wishart techniques were assessed. The Wishart (H-a classification showed higher overall as well as rice and cotton crop accuracies compared to the isodata clustering from Freeman 3-component decomposition. The classification of temporal SAR data sets independently showed that the rice crop forecasting can be advanced with the use of appropriate single date polarimetric SAR data rather than using temporal SAR amplitude data sets with the single polarization in irrigated rice ecosystems

  14. Comparison and Analysis of Geometric Correction Models of Spaceborne SAR

    Directory of Open Access Journals (Sweden)

    Weihao Jiang

    2016-06-01

    Full Text Available 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.

  15. Comparison and Analysis of Geometric Correction Models of Spaceborne SAR.

    Science.gov (United States)

    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

  16. Modelling of potentially promising SARS protease inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Plewczynski, Dariusz [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland); Hoffmann, Marcin [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Grotthuss, Marcin von [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Knizewski, Lukasz [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland); Rychewski, Leszek [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Eitner, Krystian [BioInfoBank Institute, Limanowskiego 24A/16, 60-744 Poznan (Poland); Ginalski, Krzysztof [Interdisciplinary Centre for Mathematical and Computational Modelling, ICM, Warsaw University, Pawinskiego 5a Street, 02-106 Warsaw (Poland)

    2007-07-18

    In many cases, at the beginning of a high throughput screening experiment some information about active molecules is already available. Active compounds (such as substrate analogues, natural products and inhibitors of related proteins) are often identified in low throughput validation studies on a biochemical target. Sometimes the additional structural information is also available from crystallographic studies on protein and ligand complexes. In addition, the structural or sequence similarity of various protein targets yields a novel possibility for drug discovery. Co-crystallized compounds from homologous proteins can be used to design leads for a new target without co-crystallized ligands. In this paper we evaluate how far such an approach can be used in a real drug campaign, with severe acute respiratory syndrome (SARS) coronavirus providing an example. Our method is able to construct small molecules as plausible inhibitors solely on the basis of the set of ligands from crystallized complexes of a protein target, and other proteins from its structurally homologous family. The accuracy and sensitivity of the method are estimated here by the subsequent use of an electronic high throughput screening flexible docking algorithm. The best performing ligands are then used for a very restrictive similarity search for potential inhibitors of the SARS protease within the million compounds from the Ligand.Info small molecule meta-database. The selected molecules can be passed on for further experimental validation.

  17. Rapid inactivation of SARS-like coronaviruses.

    Energy Technology Data Exchange (ETDEWEB)

    Kapil, Sanjay (Kansas State University, Manhattan, KS); Oberst, R. D. (Kansas State University, Manhattan, KS); Bieker, Jill Marie; Tucker, Mark David; Souza, Caroline Ann; Williams, Cecelia Victoria

    2004-03-01

    Chemical disinfection and inactivation of viruses is largely understudied, but is very important especially in the case of highly infectious viruses. The purpose of this LDRD was to determine the efficacy of the Sandia National Laboratories developed decontamination formulations against Bovine Coronavirus (BCV) as a surrogate for the coronavirus that causes Severe Acute Respiratory Syndrome (SARS) in humans. The outbreak of SARS in late 2002 resulted from a highly infectious virus that was able to survive and remain infectious for extended periods. For this study, preliminary testing with Escherichia coli MS-2 (MS-2) and Escherichia coli T4 (T4) bacteriophages was conducted to develop virucidal methodology for verifying the inactivation after treatment with the test formulations following AOAC germicidal methodologies. After the determination of various experimental parameters (i.e. exposure, concentration) of the formulations, final testing was conducted on BCV. All experiments were conducted with various organic challenges (horse serum, bovine feces, compost) for results that more accurately represent field use condition. The MS-2 and T4 were slightly more resistant than BCV and required a 2 minute exposure while BCV was completely inactivated after a 1 minute exposure. These results were also consistent for the testing conducted in the presence of the various organic challenges indicating that the test formulations are highly effective for real world application.

  18. The Ecosystems SAR (EcoSAR) an Airborne P-band Polarimetric InSAR for the Measurement of Vegetation Structure, Biomass and Permafrost

    Science.gov (United States)

    Rincon, Rafael F.; Fatoyinbo, Temilola; Ranson, K. Jon; Osmanoglu, Batuhan; Sun, Guoqing; Deshpande, Manohar D.; Perrine, Martin L.; Du Toit, Cornelis F.; Bonds, Quenton; Beck, Jaclyn; Lu, Daniel

    2014-01-01

    EcoSAR is a new synthetic aperture radar (SAR) instrument being developed at the NASA/ Goddard Space Flight Center (GSFC) for the polarimetric and interferometric measurements of ecosystem structure and biomass. The instrument uses a phased-array beamforming architecture and supports full polarimetric measurements and single pass interferometry. This Instrument development is part of NASA's Earth Science Technology Office Instrument Incubator Program (ESTO IIP).

  19. Research on Block Adjustment of Airborne InSAR Images

    International Nuclear Information System (INIS)

    Airborne InSAR system and InSAR data processing algorithm have been one of the hot topics in the international SAR field. Geometric constraint relation of images is set up through airborne InSAR block adjustment, adjustment parameters are adjusted and refined, and the three-dimensional(3D) ground coordinates of tie-points(TPs) are solved according to least squares theory. The number of the ground control points(GCPs) is reduced. The airborne InSAR block adjustment experiment was done using self-developed Airborne InSAR Block Adjustment Software System. The 76 airborne InSAR images which are 0.5 m resolution and cover an area of 472 square kilometers generated a block of 4 strips and 19 rows with approximately 30% overlap between adjacent strips. The study site is located in in Jiangyou Sichuan province and characterized by a hilly topography. The result meets DEM and DOM mapping accuracy requirements at scale of 1:10000

  20. Regional landslide forecasting model using interferometric SAR images

    Institute of Scientific and Technical Information of China (English)

    董育烦; 张发明; 高正夏; 蒯志要

    2008-01-01

    Method of obtaining landslide evaluating information by using Interferometric Synthetic Aperture Radar (InSAR) technique was discussed. More precision landslide surface deformation data extracted from InSAR image need take suitable SAR interferometric data selecting, path tracking, phase unwrapping processes. Then, the DEM model of scope and surface shape of the landslide was built. Combining with geological property of landslide and sliding displacements obtained from InSAR/D-InSAR images, a new landslide forecasting model called equal central angle slice method for those not obviously deformed landslides was put forward. This model breaks the limits of traditional research methods of geology. In this model, the landslide safety factor was calculated by equal central angle slice method, then considering the persistence ratio of the sliding surface based on plastic theory, the minimum safety factor was the phase when plastic area were complete persistence. This new model makes the application of InSAR/D-InSAR technology become more practical in geology hazard research.

  1. SAR image segmentation based on the advanced level set

    International Nuclear Information System (INIS)

    Image segmentation takes an important role in SAR image processing. In this paper, a SAR image segmentation method based on level set evolution combining edge feature and statistic information is proposed. In order to enhance the impact of edge on image segmentation, all edge values are homogenized according to the calculated ROA operator. Different from traditional method where the SAR distribution is often specified based on human experiences, the Edgeworth algorithm, an approximation method for statistical distribution model, gives any SAR image distribution a statistical expression. Considering the practicability of ROA operator and the adaptivity of Edgeworth series expansion at fitting statistical distribution, an energy function based on edge and region properties is defined. To implement image division, partial differential equation (PDE) of curve evolution is obtained by minimizing the function. The proposed approach uses more information from SAR images and is appropriate for any SAR images without the need for human-specified distribution pattern. Finally, the experimental results which are obtained from the SAR images of some typical regions such as rivers and buildings show the applicability of the proposed method

  2. Polarimetric SAR Tomopgraphy With TerraSAR-X By Means Of Distributed Compressed Sensing

    Science.gov (United States)

    Aguilera, E.; Nannini, M.; Antonello, A.; Marotti, L.; Prats, P.; Reigber, A.

    2012-01-01

    In SAR tomography, the vertical reflectivity function for every azimuth-range pixel is usually recovered by processing data collected using a defined repeat-pass acquisition geometry. A common and appealing approach is to generate a synthetic aperture in the elevation direction through imaging from parallel tracks. However, the quality of conventional reconstruction methods is generally dictated by the Nyquist rate, which can be considerably high. In an attempt to reduce this rate, we propose a new tomographic focusing approach that exploits correlations between neighboring azimuth-range pixels and polarimetric channels. As a matter of fact, this can be done under the framework of Distributed Com- pressed Sensing (DCS), which stems from Compressed Sensing (CS) theory, thus also exploiting sparsity in the tomographic signal. Results demonstrating the potential of the DCS methodology will be validated, for the first time, using dual-polarized data acquired at X-band by the TerraSAR-X spaceborne system.

  3. Calibration and Validation of Airborne InSAR Geometric Model

    International Nuclear Information System (INIS)

    The image registration or geo-coding is a very important step for many applications of airborne interferometric Synthetic Aperture Radar (InSAR), especially for those involving Digital Surface Model (DSM) generation, which requires an accurate knowledge of the geometry of the InSAR system. While the trajectory and attitude instabilities of the aircraft introduce severe distortions in three dimensional (3-D) geometric model. The 3-D geometrical model of an airborne SAR image depends on the SAR processor itself. Working at squinted model, i.e., with an offset angle (squint angle) of the radar beam from broadside direction, the aircraft motion instabilities may produce distortions in airborne InSAR geometric relationship, which, if not properly being compensated for during SAR imaging, may damage the image registration. The determination of locations of the SAR image depends on the irradiated topography and the exact knowledge of all signal delays: range delay and chirp delay (being adjusted by the radar operator) and internal delays which are unknown a priori. Hence, in order to obtain reliable results, these parameters must be properly calibrated. An Airborne InSAR mapping system has been developed by the Institute of Remote Sensing and Digital Earth (RADI), Chinese Academy of Sciences (CAS) to acquire three-dimensional geo-spatial data with high resolution and accuracy. To test the performance of the InSAR system, the Validation/Calibration (Val/Cal) campaign has carried out in Sichun province, south-west China, whose results will be reported in this paper

  4. Indoor experimental facility for airborne synthetic aperture radar (SAR) configurations - rail-SAR

    Science.gov (United States)

    Kirose, Getachew; Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Koenig, Francois; Narayanan, Ram M.

    2014-05-01

    The Army Research Laboratory (ARL) is developing an indoor experimental facility to evaluate and assess airborne synthetic-aperture-radar-(SAR)-based detection capabilities. The rail-SAR is located in a multi-use facility that also provides a base for research and development in the area of autonomous robotic navigation. Radar explosive hazard detection is one key sensordevelopment area to be investigated at this indoor facility. In particular, the mostly wooden, multi-story building houses a two (2) story housing structure and an open area built over a large sandbox. The housing structure includes reconfigurable indoor walls which enable the realization of multiple See-Through-The-Wall (STTW) scenarios. The open sandbox, on the other hand, allows for surface and buried explosive hazard scenarios. The indoor facility is not rated for true explosive hazard materials so all targets will need to be inert and contain surrogate explosive fills. In this paper we discuss the current system status and describe data collection exercises conducted using canonical targets and frequencies that may be of interest to designers of ultra-wideband (UWB) airborne, ground penetrating SAR systems. A bi-static antenna configuration will be used to investigate the effects of varying airborne SAR parameters such as depression angle, bandwidth, and integration angle, for various target types and deployment scenarios. Canonical targets data were used to evaluate overall facility capabilities and limitations. These data is analyzed and summarized for future evaluations. Finally, processing techniques for dealing with RF multi-path and RFI due to operating inside the indoor facility are described in detail. Discussion of this facility and its capabilities and limitations will provide the explosive hazard community with a great airborne platform asset for sensor to target assessment.

  5. Radar observation of Venus' terrestrial analogues using TecSAR X-band SAR

    Science.gov (United States)

    Blumberg, D. G.

    2012-04-01

    Venus is shrouded in a dense CO2 atmosphere that prevents us from viewing the surface in visible light or with optronic sensors. Long wavelengths are required to 'see' through the dense atmosphere. In the early 1990s, the S-band synthetic aperture radar of the Magellan spacecraft acquired images of a variety of surface features on Venus, including morphologies attributed to wind processes. These include sand dunes, wind-sculpted hills (yardangs), and almost 6000 wind streaks. These aeolian landscapes were formed and shaped by near surface atmospheric circulation and local winds. These can serve as local markers, each providing an integrated wind direction. Since the Magellan mission, there were no missions to Venus until the Venus Express Mission of 2005 to examine the upper atmosphere. The future will probably include high-resolution SAR images of Venus. This poster will demonstrate high resolution SAR images in X-band from the TecSAR sensor launched by Israel in 2008. Observations of wind streaks, dunes and impact craters in desert areas will show the wealth of information that is extracted from high-res X-band data. Detailed images of Aurounga impact crater in Chad, Kelso dunes, California and Pisgah lava flow show immense detail of the morphologies associated with these features. These are compared with Magellan images of sites on Venus and SRL data in C and L-bands. The X-band provides extremely high resolution and resembles optical data much more than the longer wavelengths.

  6. FlexSAR, a high quality, flexible, cost effective, prototype SAR system

    Science.gov (United States)

    Jensen, Mark; Knight, Chad; Haslem, Brent

    2016-05-01

    The FlexSAR radar system was designed to be a high quality, low-cost, flexible research prototype instrument. Radar researchers and practitioners often desire the ability to prototype new or advanced configurations, yet the ability to enhance or upgrade existing radar systems can be cost prohibitive. FlexSAR answers the need for a flexible radar system that can be extended easily, with minimal cost and time expenditures. The design approach focuses on reducing the resources required for developing and validating new advanced radar modalities. Such an approach fosters innovation and provides risk reduction since actual radar data can be collected in the appropriate mode, processed, and analyzed early in the development process. This allows for an accurate, detailed understanding of the corresponding trade space. This paper is a follow-on to last years paper and discusses the advancements that have been made to the FlexSAR system. The overall system architecture is discussed and presented along with several examples illustrating the system utility.

  7. SAR image effects on coherence and coherence estimation.

    Energy Technology Data Exchange (ETDEWEB)

    Bickel, Douglas Lloyd

    2014-01-01

    Radar coherence is an important concept for imaging radar systems such as synthetic aperture radar (SAR). This document quantifies some of the effects in SAR which modify the coherence. Although these effects can disrupt the coherence within a single SAR image, this report will focus on the coherence between separate images, such as for coherent change detection (CCD) processing. There have been other presentations on aspects of this material in the past. The intent of this report is to bring various issues that affect the coherence together in a single report to support radar engineers in making decisions about these matters.

  8. The physics of vibrating scatterers in SAR imagery

    Science.gov (United States)

    André, D. B.; Blacknell, D.; Muff, D. G.; Nottingham, M. R.

    2011-06-01

    Measurement times for synthetic aperture radar (SAR) image collection can take from the order of seconds to minutes and consequently the technique is subject to imaging artefacts due to target motion. For example, imaged moving targets can be displaced and unfocussed and similarly for vibrating targets. Current understanding of this phenomenon is somewhat esoteric however this paper puts forward and demonstrates a visual explanation via the physics of modulated scatterer SAR images in the Fourier domain. This novel approach has led to an imagery analyst aid which associates a distinctive signature to modulated scatterer artefacts in SAR imagery and to an associated filter.

  9. Multitemporal landslides inventory map updating using spaceborne SAR analysis

    OpenAIRE

    Del Ventisette C.; Righini G.; Moretti S.; Casagli N.

    2014-01-01

    Deep seated gravitational slope deformation and slow moving landslides on large areas were analyzed by spaceborne SAR interferometry: a test site in the Italian Alps of about 300 km2 was selected for updating pre-existing landslide inventory maps based on the advanced interferometric processing technique (A-DInSAR). SAR images from ERS-1/2 satellites (1995–2000) and from Envisat satellite (2002–2009) have been used, allowing the deferred-time analysis of past movements and the record of r...

  10. An overview on SAR measurements of sea surface wind

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Studies show that synthetic aperture radar (SAR) has the capability of providing high-resolution (sub-kilometer) sea surface wind fields. This is very useful for applications where knowledge of the sea surface wind at fine scales is crucial. This paper aims to review the latest work on sea surface wind field retrieval using SAR images. As shown, many different approaches have been developed for retrieving wind speed and wind direction. However, much more work will be required to fully exploit the SAR data for improving the retrieval accuracy of high-resolution winds and for producing wind products in an operational sense.

  11. The Danish (Q)SAR Database Update Project

    DEFF Research Database (Denmark)

    Nikolov, Nikolai Georgiev; Dybdahl, Marianne; Abildgaard Rosenberg, Sine;

    2013-01-01

    The Danish (Q)SAR Database is a collection of predictions from quantitative structure–activity relationship ((Q)SAR) models for over 70 environmental and human health-related endpoints (covering biodegradation, metabolism, allergy, irritation, endocrine disruption, teratogenicity, mutagenicity......, carcinogenicity and others), each of them available for 185,000 organic substances. The database has been available online since 2005 (http://qsar.food.dtu.dk). A major update project for the Danish (Q)SAR database is under way, with a new online release planned in the beginning of 2015. The updated version will...

  12. LTE modem power consumption, SAR and RF signal strength emulation

    DEFF Research Database (Denmark)

    Musiige, Deogratius; Vincent, Laulagnet; Anton, François

    2012-01-01

    This paper presents a new methodology for emulating the LTE modem power consumption, emitted SAR and RF signal strength when transmitting an LTE signal. The inputs of the methodology are: modem logical/protocol commands, time advance, near-field specifier, and antenna characteristics. The power...... emulation model(s) are computed by a two layer 451 neural network based on physical power measurements. SAR is emulated by polynomial interpolation models based on FDTD simulations. The accuracies of the mathematical function approximations for the emulation models of power and SAR are 5.19% and 3.......6% respectively. The RF signal strength is emulated by an analytical model....

  13. Multi-look polarimetric SAR image filtering using simulated annealing

    DEFF Research Database (Denmark)

    Schou, Jesper

    2000-01-01

    Based on a previously published algorithm capable of estimating the radar cross-section in synthetic aperture radar (SAR) intensity images, a new filter is presented utilizing multi-look polarimetric SAR images. The underlying mean covariance matrix is estimated from the observed sample covariance...... matrices, and by applying a set of small orientation-dependent filters in an iterative scheme, the input image becomes highly filtered while maintaining most of the structures in the scene. Results using multi-look polarimetric C-band data from the Danish airborne polarimetric SAR, EMISAR, are presented....

  14. The Danish (Q)SAR Database Update Project

    DEFF Research Database (Denmark)

    Nikolov, Nikolai Georgiev; Dybdahl, Marianne; Abildgaard Rosenberg, Sine;

    2013-01-01

    , carcinogenicity and others), each of them available for 185,000 organic substances. The database has been available online since 2005 (http://qsar.food.dtu.dk). A major update project for the Danish (Q)SAR database is under way, with a new online release planned in the beginning of 2015. The updated version will......The Danish (Q)SAR Database is a collection of predictions from quantitative structure–activity relationship ((Q)SAR) models for over 70 environmental and human health-related endpoints (covering biodegradation, metabolism, allergy, irritation, endocrine disruption, teratogenicity, mutagenicity...

  15. Coronaviridae and SARS-associated Coronavirus Strain HSR1

    OpenAIRE

    Vicenzi, Elisa; Canducci, Filippo; Pinna, Debora; Mancini, Nicasio; Carletti, Silvia; Lazzarin, Adriano; Bordignon, Claudio; Poli, Guido; Clementi, Massimo

    2004-01-01

    During the recent severe acute respiratory (SARS) outbreak, the etiologic agent was identified as a new coronavirus (CoV). We have isolated a SARS-associated CoV (SARS-CoV) strain by injecting Vero cells with a sputum specimen from an Italian patient affected by a severe pneumonia; the patient traveled from Vietnam to Italy in March 2003. Ultrastructural analysis of infected Vero cells showed the virions within cell vesicles and around the cell membrane. The full-length viral genome sequence ...

  16. Feasibility study of an FM-CW SAR system

    OpenAIRE

    Wit, J.J.M. de; Hoogeboom, P.; Otten, M.P.G.

    2001-01-01

    There is an increasing interest in low-cost, high-resolution imaging radar systems to be operated from small and maybe even unmanned platforms. Existing imaging systems are generally too heavy for small platforms, or too expensive in day-to-day use to be applied in small-scale civil applications. Combining the compactness of FM-CW radar systems and the high azimuth resolution of SAR systems, an FM-CW SAR sensor could be of interest for small-scale applications. The feasibility of FM-CW SAR in...

  17. SAR: A novel application for FM-CW radars

    OpenAIRE

    Wit, J.J.M. de; Hoogeboom, P.

    2001-01-01

    For small-scale earth observation applications, there ia a special interest in low-cost, high-resolution imaging radars small, enough to be operated from small, possibly unmanned aircraft. The combination of FM-CW technology and the high resolution of SAR systems should result in such a small, cost-effective imaging radar. In a new project the feasibility of FM-CW SAR is studied. SAR algorithms that take the typical characteristics of FM-CW signals into account will be developed. Furthermore,...

  18. Genome organization of the SARS-CoV

    DEFF Research Database (Denmark)

    Xu, Jing; Hu, Jianfei; Wang, Jing;

    2003-01-01

    Annotation of the genome sequence of the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) is indispensable to understand its evolution and pathogenesis. We have performed a full annotation of the SARS-CoV genome sequences by using annotation programs publicly available...... of known genes, revealing that the SARS-CoV genome is a small and compact one with overlapped coding regions. The most striking discovery is that an ORF locates on the minus strand. We have also annotated non-coding regions and identified the transcription regulating sequences (TRS) in the intergenic...

  19. An energy efficient noise-shaping SAR ADC in 28 nm FDSOI

    OpenAIRE

    Garvik, Harald

    2015-01-01

    In a noise-shaping SAR ADC, oversampling and noise shaping are used to increase the conversion accuracy beyond that the SAR exhibits alone. To implement the noise shaping, the residue voltage present at the SAR DAC plates after each conversion is exploited, and fed into a loop filter connected to an extra input of the SAR comparator. In this thesis, an energy efficient noise-shaping SAR ADC for medical ultrasound applications is designed in 28 nm FDSOI. The design specifica...

  20. Speckle Suppression Method for SAR Image

    Directory of Open Access Journals (Sweden)

    Jiming Guo

    2013-04-01

    Full Text Available In this study, a new speckle reduction method was proposed in terms of by Bidimensional Empirical Mode Decomposition (BEMD. In this method, the SAR image containing speckle noise was decomposed into a number of elementary components by using BEMD and then the extremal points are done the boundary equivalent extension after screening and the residual continue to be done the boundary equivalent extension until screening is completed, finally, the image was reconstructed, which reduced the speckle noise. Experimental results show that this method has good effect on suppressing speckle noise, compared to the average filter, median filter and gaussian filter and has advantages of sufficiently retaining edge and detail information while suppressing speckle noise.

  1. Mobile Phone Signal Analysis and SAR Calculation

    International Nuclear Information System (INIS)

    In this paper, a generation and analysis of mobile phone signal in the frequency range, 950 MHz and 1800 MHz was presented. The mobile signals have been generated with different values of power, -30 dBm up to 30 dBm, using Radio frequency generator type CWHP83712B. The generated signal transmitted by horn antenna with coaxial cable, then detected by a synthesized CW generator as a spectrum analyzer HP8592L with another horn antennas as a receiver. The generated power tabulated with the required RMS voltage which can be used to calibrate the system to detect the required signal related to the power and the frequency, and the specific absorption rate ( SAR) of the system can be calculated to calibrate the system as a source of electromagnetic radiation. Also, the results illustrate the relation between temperature and exposure time for the two frequencies

  2. Radionuclide release calculations for SAR-08

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, Gavin; Miller, Alex; Smith, Graham; Jackson, Duncan (Enviros Consulting Ltd, Wolverhampton (United Kingdom))

    2008-04-15

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  3. Radionuclide release calculations for SAR-08

    International Nuclear Information System (INIS)

    Following a review by the Swedish regulatory authorities of the post-closure safety assessment of the SFR 1 disposal facility for low and intermediate waste (L/ILW), SAFE, the SKB has prepared an updated assessment called SAR-08. This report describes the radionuclide release calculations that have been undertaken as part of SAR-08. The information, assumptions and data used in the calculations are reported and the results are presented. The calculations address issues raised in the regulatory review, but also take account of new information including revised inventory data. The scenarios considered include the main case of expected behaviour of the system, with variants; low probability releases, and so-called residual scenarios. Apart from these scenario uncertainties, data uncertainties have been examined using a probabilistic approach. Calculations have been made using the AMBER software. This allows all the component features of the assessment model to be included in one place. AMBER has been previously used to reproduce results the corresponding calculations in the SAFE assessment. It is also used in demonstration of the IAEA's near surface disposal assessment methodology ISAM and has been subject to very substantial verification tests and has been used in verifying other assessment codes. Results are presented as a function of time for the release of radionuclides from the near field, and then from the far field into the biosphere. Radiological impacts of the releases are reported elsewhere. Consideration is given to each radionuclide and to each component part of the repository. The releases from the entire repository are also presented. The peak releases rates are, for most scenarios, due to organic C-14. Other radionuclides which contribute to peak release rates include inorganic C-14, Ni-59 and Ni-63. (author)

  4. Analysing multitemporal SAR images for forest mapping

    Science.gov (United States)

    Maghsoudi, Yasser; Collins, Michael J.; Leckie, Donald G.

    2010-10-01

    The objective of this paper is twofold: first, to presents a generic approach for the analysis of Radarsat-1 multitemporal data and, second, to presents a multi classifier schema for the classification of multitemporal images. The general approach consists of preprocessing step and classification. In the preprocessing stage, the images are calibrated and registered and then temporally filtered. The resulted multitemporally filtered images are subsequently used as the input images in the classification step. The first step in a classifier design is to pick up the most informative features from a series of multitemporal SAR images. Most of the feature selection algorithms seek only one set of features that distinguish among all the classes simultaneously and hence a limited amount of classification accuracy. In this paper, a class-based feature selection (CBFS) was proposed. In this schema, instead of using feature selection for the whole classes, the features are selected for each class separately. The selection is based on the calculation of JM distance of each class from the rest of classes. Afterwards, a maximum likelihood classifier is trained on each of the selected feature subsets. Finally, the outputs of the classifiers are combined through a combination mechanism. Experiments are performed on a set of 34 Radarsat-1 images acquired from August 1996 to February 2007. A set of 9 classes in a forest area are used in this study. Classification results confirm the effectiveness of the proposed approach compared with the case of single feature selection. Moreover, the proposed process is generic and hence is applicable in different mapping purposes for which a multitemporal set of SAR images are available.

  5. Decreasing range resolution of a SAR image to permit correction of motion measurement errors beyond the SAR range resolution

    Science.gov (United States)

    Doerry, Armin W.; Heard, Freddie E.; Cordaro, J. Thomas

    2010-07-20

    Motion measurement errors that extend beyond the range resolution of a synthetic aperture radar (SAR) can be corrected by effectively decreasing the range resolution of the SAR in order to permit measurement of the error. Range profiles can be compared across the slow-time dimension of the input data in order to estimate the error. Once the error has been determined, appropriate frequency and phase correction can be applied to the uncompressed input data, after which range and azimuth compression can be performed to produce a desired SAR image.

  6. Pulse-based internal calibration of polarimetric SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Skou, Niels; Christensen, Erik Lintz

    Internal calibration greatly diminishes the dependence on calibration target deployment compared to external calibration. Therefore the Electromagnetics Institute (EMI) at the Technical University of Denmark (TUD) has equipped its polarimetric SAR, EMISAR, with several calibration loops and devel...

  7. An Improved GLRT Method for Target Detection in SAR Imagery

    Directory of Open Access Journals (Sweden)

    Ju Yingyun

    2015-01-01

    Full Text Available Automatic ground vehicle detection based on SAR imagery is one of the important military applications of SAR. A region-based generalized likelihood ratio test (GLRT method is proposed in this paper, and this method combines the GLRT detection theory and image segmentation technology. First, the SAR imagery is roughly segmented as land clutter region and potential target region through the split and merge procedure often used for processing the original images. Then, based on the segmentation results, the reasonable statistical models for the data in the two regions are built respectively. Finally, with the knowledge of statistical characteristics of clutter and target, GLRT detection method is applied to the each pixel in the potential target region to obtain more accurate detection results. Experimental results based on real SAR data show that the proposed method can effectively detect the ground vehicle targets from the land clutter with excellent accuracy and speed.

  8. A beamforming algorithm for bistatic SAR image formation.

    Energy Technology Data Exchange (ETDEWEB)

    Yocky, David Alan; Wahl, Daniel Eugene; Jakowatz, Charles V., Jr.

    2010-03-01

    Beamforming is a methodology for collection-mode-independent SAR image formation. It is essentially equivalent to backprojection. The authors have in previous papers developed this idea and discussed the advantages and disadvantages of the approach to monostatic SAR image formation vis--vis the more standard and time-tested polar formatting algorithm (PFA). In this paper we show that beamforming for bistatic SAR imaging leads again to a very simple image formation algorithm that requires a minimal number of lines of code and that allows the image to be directly formed onto a three-dimensional surface model, thus automatically creating an orthorectified image. The same disadvantage of beamforming applied to monostatic SAR imaging applies to the bistatic case, however, in that the execution time for the beamforming algorithm is quite long compared to that of PFA. Fast versions of beamforming do exist to help alleviate this issue. Results of image reconstructions from phase history data are presented.

  9. SAR imaging technique for reduction of sidelobes and noise

    Science.gov (United States)

    Nguyen, Lam

    2009-05-01

    Multiplicative noise poses a big challenge for SAR imaging system, in which energy from the sidelobes of large RCS man-made and natural clutter objects spread throughout the resulting SAR imagery. Detection of small RCS targets is very difficult since their signatures might be obscured or even embedded in this multiplicative noise floor that is proportional to the RCS of surrounding clutter objects. ARL has developed a Recursive Sidelobe Minimization (RSM) technique that is combined with the standard backprojection image formation algorithm to suppress the multiplicative noise floor in the resulting SAR imagery. In this paper, we present the Recursive Sidelobe Minimization (RSM) technique. Although the technique is originally developed and tested using data from the Army Research Lab (ARL) UWB Synchronous Impulse Reconstruction (SIRE) forward-looking radar, it is also applicable for other SAR data sets with different configurations.

  10. Road network extraction in classified SAR images using genetic algorithm

    Institute of Scientific and Technical Information of China (English)

    肖志强; 鲍光淑; 蒋晓确

    2004-01-01

    Due to the complicated background of objectives and speckle noise, it is almost impossible to extract roads directly from original synthetic aperture radar(SAR) images. A method is proposed for extraction of road network from high-resolution SAR image. Firstly, fuzzy C means is used to classify the filtered SAR image unsupervisedly, and the road pixels are isolated from the image to simplify the extraction of road network. Secondly, according to the features of roads and the membership of pixels to roads, a road model is constructed, which can reduce the extraction of road network to searching globally optimization continuous curves which pass some seed points. Finally, regarding the curves as individuals and coding a chromosome using integer code of variance relative to coordinates, the genetic operations are used to search global optimization roads. The experimental results show that the algorithm can effectively extract road network from high-resolution SAR images.

  11. Change detection in polarimetric SAR data over several time points

    DEFF Research Database (Denmark)

    Conradsen, Knut; Nielsen, Allan Aasbjerg; Skriver, Henning

    2014-01-01

    A test statistic for the equality of several variance-covariance matrices following the complex Wishart distribution is introduced. The test statistic is applied successfully to detect change in C-band EMISAR polarimetric SAR data over four time points....

  12. a Rail Central Displacement Method about Gb-Sar

    Science.gov (United States)

    Peng, J.; Cai, J.; Yang, H.

    2016-06-01

    This paper presents a new method to correct rail errors of Ground Based Synthetic Aperture Radar (GB-SAR) in the discontinue mode. Generally, "light positioning" is performed to mark the GB-SAR position in the dis-continuous observation mode. Usually we assume there is no difference between the marked position and the real installation position. But in fact, it is hard to keep the GB-SAR positions of two campaigns the same, so repositioning errors can't be neglected. In order to solve this problem, we propose an algorithm to correct the rail error after analyzing the GB-SAR rail error geometry. Results of the simulation experiment and the real experiment of a landslide in Lvliang, Shanxi, China, show the proposed method achieves an mm-level precision, enabling the D-GBSAR mode to be used in engineering projects.

  13. SAR China Land Mapping Project: Development, Production and Potential Applications

    International Nuclear Information System (INIS)

    Large-area, seamless synthetic aperture radar (SAR) mosaics can reflect overall environmental conditions and highlight general trends in observed areas from a macroscopic standpoint, and effectively support research at the global scale, which is in high demand now across scientific fields. The SAR China Land Mapping Project (SCLM), supported by the Digital Earth Science Platform Project initiated and managed by the Center for Earth Observation and Digital Earth, Chinese Academy of Sciences (CEODE), is introduced in this paper. This project produced a large-area SAR mosaic dataset and generated the first complete seamless SAR map covering the entire land area of China using EnviSat-ASAR images. The value of the mosaic map is demonstrated by some potential applications in studies of urban distribution, rivers and lakes, geologic structures, geomorphology and paleoenvironmental change

  14. A Review of Spaceborne SAR Algorithm for Image Formation

    Directory of Open Access Journals (Sweden)

    Li Chun-sheng

    2013-03-01

    Full Text Available This paper firstly reviews the history and trends in development of spaceborne Synthetic Aperture Radar (SAR satellite technology in American and European countries. Besides, the basic information of the launched satellites and the future satellite plans are introduced. Then this paper summaries and assorts the imaging algorithm of spaceborn SAR satellite and analyzes the advantages and disadvantages of each algorithm. Moreover, the scope and the application status of each algorithm are presented. And then the paper elaborates trends of SAR imaging algorithm, which mainly introduces the algorithms based on compressive sensing theory and new image modes, and the results of simulation are also illustrated. At last, the paper summaries the development direction of spaceborne SAR imaging algorithm.

  15. Brief Analysis on the Development and Application of Spaceborne SAR

    Directory of Open Access Journals (Sweden)

    Deng Yun-kai

    2012-03-01

    Full Text Available Spaceborne SAR, which is a kind of initiatively microwave imaging sensor, plays an important role in gathering information with its capability of all-day and all-weather imaging, and has become an indispensable sensor for observing the earth. With the development of SAR techniques, Spaceborne SAR has been provided with the ability of High-Resolution Wide-Swath, miniaturization with low cost, bistatic and multi-mode imaging, and Ground Moving Target Indicating (GMTI, so more accurate information about the culture could be obtained with lower cost. In the meantime, more technique problems with muliti-mode, new work system and complex environment are arising and needed to be solved. The main work of this paper is discussing the current situation and the future development of Spaceborne SAR.

  16. Crop Classification Using Short-Revisit Multitemporal SAR Data

    DEFF Research Database (Denmark)

    Skriver, Henning; Mattia, Francesco; Satalino, Giuseppe; Balenzano, Anna; Pauwels, Valentijn R. N.; Verhoest, Niko E. C.; Davidson, Malcolm

    2011-01-01

    Classification of crops and other land cover types is an important application of both optical/infrared and SAR satellite data. It is already an import application of present satellite systems, as it will be for planned missions, such as the Sentinels. An airborne SAR data set with a short revisit...... time acquired by the German ESAR system during the ESA-campaign, AgriSAR 2006, has been used to assess the performance of different polarization modes for crop classification. Both C-and L-band SAR data were acquired over the Demmin agricultural test site in North Eastern Germany on a weekly basis...... during the growing season. Single-and dual-polarization, and fully polarimetric data have been used in the analysis (fully polarimetric data were only available at L-band). The main results of the analysis are, that multitemporal acquisitions are very important for single-and dual-polarization modes, and...

  17. Massachusetts Bay - Internal wave packets digitized from SAR imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This feature class contains internal wave packets digitized from SAR imagery at 1:350,000 scale in Massachusetts Bay. Internal waves are nonsinusoidal waves that...

  18. Stellwagen Bank National Marine Sanctuary - Synthetic Aperture Radar (SAR) Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This geodatabase contains Synthetic Aperture Radar images (SAR), which consist of a fine resolution (12.5-50m), two-dimensional radar backscatter map of the...

  19. Evolution and Variation of the SARS-CoV Genome

    Institute of Scientific and Technical Information of China (English)

    Jianfei Hu; Zizhang Zhang; Wei Wei; Songgang Li; Jun Wang; Jian Wang; Jun Yu; Huanming Yang; Jing Wang; Jing Xu; Wei Li; Yujun Han; Yan Li; Jia Ji; Jia Ye; Zhao Xu

    2003-01-01

    Knowledge of the evolution of pathogens is of great medical and biological significance to the prevention, diagnosis, and therapy of infectious diseases. In order to understand the origin and evolution of the SARS-CoV (severe acute respiratory syndrome-associated coronavirus), we collected complete genome sequences of all viruses available in GenBank, and made comparative analyses with the SARSCoV. Genomic signature analysis demonstrates that the coronaviruses all take the TGTT as their richest tetranucleotide except the SARS-CoV. A detailed analysis of the forty-two complete SARS-CoV genome sequences revealed the existence of two distinct genotypes, and showed that these isolates could be classified into four groups. Our manual analysis of the BLASTN results demonstrates that the HE (hemagglutinin-esterase) gene exists in the SARS-CoV, and many mutations made it unfamiliar to us.

  20. Characteristics of merchant vessels in spaceborne SAR imagery

    Science.gov (United States)

    Chen, Peng; Huang, Weigen; Yang, Jingsong; Fu, Bin; Lou, XiuLin; Zhang, Huagon

    2006-12-01

    Ship features in high-resolution spaceborne Synthetic Aperture Radar (SAR) imagery has crucial significance for ship classification from satellite. In this paper, we discuss the features of merchant Ships including oil tanker, container ship and bulk carrier in SAR imagery, which is comprised of geometrical feature, scattering feature, tonnage information with Radar Cross Section (RCS) and wake. The study show that the ship lengths measured from SAR imagery has a good correlation with the real lengths, but the correlation of ship beam is worse. Ship scattering feature has positive correlation with the ship structure, which maybe is a feature to distinguish container ship from other vessels. A new equation about ship length and its displacement in tons is presented in this paper. The relation suggested by Skolnik M.I between ship tonnage and RCS is tested but not validated. We also validate the means of extracting ship speed by ship turbulence wake in SAR imagery.

  1. Non-Parametric High-Resolution SAR Imaging

    OpenAIRE

    Glentis, George-Othan; Zhao, Kexin; Jakobsson, Andreas; Li, Jian

    2013-01-01

    The development of high-resolution two-dimensional spectral estimation techniques is of notable interest in synthetic aperture radar (SAR) imaging. Typically, data-independent techniques are exploited to form the SAR images, although such approaches will suffer from limited resolution and high sidelobe levels. Recent work on data-adaptive approaches have shown that both the iterative adaptive approach (IAA) and the sparse learning via iterative minimization (SLIM) algorithm offer ...

  2. Deformation measurement and monitoring with Ground-Based SAR

    OpenAIRE

    Monserrat Hernández, Oriol

    2012-01-01

    The Ground-Based Synthetic Aperture Radar (GB-SAR) is a relatively new technique, which in the last ten years has gained interest as deformation measurement and monitoring tool. The GB-SAR technique is based on an imaging radar-based sensor, which o ers high sensitivity to small displacements, in the region of sub-millimetres to millimetres, long-range measurements, which can work up to some kilometres, and massive deformation measurement cap...

  3. Taiga forest stands and SAR: Monitoring for subarctic global change

    International Nuclear Information System (INIS)

    In preparation for the first European Earth Remote Sensing (ERS-1) mission, a series of multitemporal, multifrequency, multipolarization aircraft synthetic aperture radar (SAR) data sets were acquired over the Bonanza Creek Experimental Forest near Fairbanks, Alaska in March 1988. Significant change in radar backscatter was observed over the two-week experimental period due to changing environmental conditions. These preliminary results are presented to illustrate the opportunity afforded by the ERS-1 SAR to monitor temporal change in forest ecosystems

  4. Automatic target recognition in SAR images using multilinear analysis

    OpenAIRE

    Porgès, Tristan; Favier, Gérard

    2011-01-01

    International audience Multilinear analysis provides a powerful mathematical framework for analyzing synthetic aperture radar (SAR) images resulting from the interaction of multiple factors like sky luminosity and viewing angles, while preserving their original shape. In this paper, we propose a multilinear principal component analysis (MPCA) algorithm for target recognition in SAR images. First, we form a high order tensor with the training image set and we apply the higher-order singular...

  5. SAR image formation with azimuth interpolation after azimuth transform

    Science.gov (United States)

    Doerry; Armin W. , Martin; Grant D. , Holzrichter; Michael W.

    2008-07-08

    Two-dimensional SAR data can be processed into a rectangular grid format by subjecting the SAR data to a Fourier transform operation, and thereafter to a corresponding interpolation operation. Because the interpolation operation follows the Fourier transform operation, the interpolation operation can be simplified, and the effect of interpolation errors can be diminished. This provides for the possibility of both reducing the re-grid processing time, and improving the image quality.

  6. Archived 1976-1985 JPL Aircraft SAR Data

    Science.gov (United States)

    Thompson, Thomas W.; Blom, Ronald G.

    2016-01-01

    This report describes archived data from the Jet Propulsion Laboratory (JPL) aircraft radar expeditions in the mid-1970s through the mid-1980s collected by Ron Blom, JPL Radar Geologist. The dataset was collected during Ron's career at JPL from the 1970s through 2015. Synthetic Aperture Radar (SAR) data in the 1970s and 1980s were recorded optically on long strips of film. SAR imagery was produced via an optical, holographic technique that resulted in long strips of film imagery.

  7. Improving InSAR geodesy using Global Atmospheric Models

    OpenAIRE

    Jolivet, Romain,; Agram, Piyush Shanker; Lin, Nina Y.; Simons, Mark; Doin, Marie-Pierre; Peltzer, Gilles; Li, Zhenhong

    2014-01-01

    Spatial and temporal variations of pressure, temperature, and water vapor content in the atmosphere introduce significant confounding delays in interferometric synthetic aperture radar (InSAR) observations of ground deformation and bias estimates of regional strain rates. Producing robust estimates of tropospheric delays remains one of the key challenges in increasing the accuracy of ground deformation measurements using InSAR. Recent studies revealed the efficiency of global atmo...

  8. Initial viral load and the outcomes of SARS

    Science.gov (United States)

    Chu, Chung-Ming; Poon, Leo L.M.; Cheng, Vincent C.C.; Chan, Kin-Sang; Hung, Ivan F.N.; Wong, Maureen M.L.; Chan, Kwok-Hung; Leung, Wah-Shing; Tang, Bone S.F.; Chan, Veronica L.; Ng, Woon-Leung; Sim, Tiong-Chee; Ng, Ping-Wing; Law, Kin-Ip; Tse, Doris M.W.; Peiris, Joseph S.M.; Yuen, Kwok-Yung

    2004-01-01

    Background Severe acute respiratory syndrome (SARS) is caused by a novel coronavirus. It may progress to respiratory failure, and a significant proportion of patients die. Preliminary data suggest that a high viral load of the SARS coronavirus is associated with adverse outcomes in the intensive care unit, but the relation of viral load to survival is unclear. Methods We prospectively studied an inception cohort of 133 patients with virologically confirmed SARS who were admitted to 2 general acute care hospitals in Hong Kong from Mar. 24 to May 4, 2003. The patients were followed until death or for a minimum of 90 days. We used Cox proportional hazard modelling to analyze potential predictors of survival recorded at the time of presentation, including viral load from nasopharyngeal specimens (measured by quantitative reverse transcriptase polymerase chain reaction [PCR] of the SARS-associated coronavirus). Results Thirty-two patients (24.1%) met the criteria for acute respiratory distress syndrome, and 24 patients (18.0%) died. The following baseline factors were independently associated with worse survival: older age (61–80 years) (adjusted hazard ratio [HR] 5.24, 95% confidence interval [CI] 2.03–13.53), presence of an active comorbid condition (adjusted HR 3.36, 95% CI 1.44–7.82) and higher initial viral load of SARS coronavirus, according to quantitative PCR of nasopharyngeal specimens (adjusted HR 1.21 per log10 increase in number of RNA copies per millilitre, 95% CI 1.06–1.39). Interpretation We found preliminary evidence that higher initial viral load is independently associated with worse prognosis in SARS. Mortality data for patients with SARS should be interpreted in light of age, comorbidity and viral load. These considerations will be important in future studies of SARS. PMID:15557587

  9. Nano(Q)SAR: Challenges, pitfalls and perspectives.

    Science.gov (United States)

    Tantra, Ratna; Oksel, Ceyda; Puzyn, Tomasz; Wang, Jian; Robinson, Kenneth N; Wang, Xue Z; Ma, Cai Y; Wilkins, Terry

    2015-01-01

    Regulation for nanomaterials is urgently needed, and the drive to adopt an intelligent testing strategy is evident. Such a strategy will not only provide economic benefits but will also reduce moral and ethical concerns arising from animal testing. For regulatory purposes, such an approach is promoted by REACH, particularly the use of quantitative structure-activity relationships [(Q)SAR] as a tool for the categorisation of compounds according to their physicochemical and toxicological properties. In addition to compounds, (Q)SAR has also been applied to nanomaterials in the form of nano(Q)SAR. Although (Q)SAR in chemicals is well established, nano(Q)SAR is still in early stages of development and its successful uptake is far from reality. This article aims to identify some of the pitfalls and challenges associated with nano-(Q)SARs in relation to the categorisation of nanomaterials. Our findings show clear gaps in the research framework that must be addressed if we are to have reliable predictions from such models. Three major barriers were identified: the need to improve quality of experimental data in which the models are developed from, the need to have practical guidelines for the development of the nano(Q)SAR models and the need to standardise and harmonise activities for the purpose of regulation. Of these three, the first, i.e. the need to improve data quality requires immediate attention, as it underpins activities associated with the latter two. It should be noted that the usefulness of data in the context of nano-(Q)SAR modelling is not only about the quantity of data but also about the quality, consistency and accessibility of those data. PMID:25211549

  10. Comparing satellite SAR and wind farm wake models

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Vincent, P.; Husson, R.;

    2015-01-01

    . These extend several tens of kilometres downwind e.g. 70 km. Other SAR wind maps show near-field fine scale details of wake behind rows of turbines. The satellite SAR wind farm wake cases are modelled by different wind farm wake models including the PARK microscale model, the Weather Research and...... Forecasting (WRF) model in high resolution and WRF with coupled microscale parametrization....

  11. Geometry-based SAR curvilinear feature selection for damage detection

    OpenAIRE

    Brett, P.T.B.,; Guida, R.

    2012-01-01

    Bright curvilinear features in Synthetic Aperture Radar (SAR) images arising from the geometry of urban structures have been successfully used for estimating urban earthquake damage, using single pre- and post-event high resolution amplitude SAR images. In this paper, further automation of the process of selecting candidate curvilinear features for change detection is proposed, based on a model selection using priors derived from idealised building geometry. The technique is demonstrated usin...

  12. Approaching doomsday: how SARS was presented in the Norwegian media

    OpenAIRE

    Hansen, Ketil Fred

    2009-01-01

    This article reviews why SARS received so much media attention in Norway, beginning with descriptions of the dynamics and dilemmas faced in health risk communication from the point of view of medical experts and generalist journalists. How the Norwegian media covered SARS is then described and analysed in relation to these risk communication dynamics and dilemmas. Based on the description and short analysis, connotations of the main narratives in the different phases of the ...

  13. Evaluation of Polarimetric SAR Decomposition for Classifying Wetland Vegetation Types

    OpenAIRE

    Sang-Hoon Hong; Hyun-Ok Kim; Shimon Wdowinski; Emanuelle Feliciano

    2015-01-01

    The Florida Everglades is the largest subtropical wetland system in the United States and, as with subtropical and tropical wetlands elsewhere, has been threatened by severe environmental stresses. It is very important to monitor such wetlands to inform management on the status of these fragile ecosystems. This study aims to examine the applicability of TerraSAR-X quadruple polarimetric (quad-pol) synthetic aperture radar (PolSAR) data for classifying wetland vegetation in the Everglades. We ...

  14. Exact analysis of the azimuth resolution characters of squint SAR

    Institute of Scientific and Technical Information of China (English)

    李树; 王鹰; 赵亦工

    2004-01-01

    Based on the motion of platform and the scanning rules of the squint SAR, this paper constructs an exact slant range model between a point target and APC, then presents a novel analysis method of the high resolution characters in azimuth of squint SAR. By deeply researching the length of synthetic aperture and the azimuth resolution, we give the application conditions of various formulae about the two important parameters, which is vital to the exact imaging and brief but reasonable processing.

  15. An analytical solution for improved HIFU SAR estimation

    International Nuclear Information System (INIS)

    Accurate determination of the specific absorption rates (SARs) present during high intensity focused ultrasound (HIFU) experiments and treatments provides a solid physical basis for scientific comparison of results among HIFU studies and is necessary to validate and improve SAR predictive software, which will improve patient treatment planning, control and evaluation. This study develops and tests an analytical solution that significantly improves the accuracy of SAR values obtained from HIFU temperature data. SAR estimates are obtained by fitting the analytical temperature solution for a one-dimensional radial Gaussian heating pattern to the temperature versus time data following a step in applied power and evaluating the initial slope of the analytical solution. The analytical method is evaluated in multiple parametric simulations for which it consistently (except at high perfusions) yields maximum errors of less than 10% at the center of the focal zone compared with errors up to 90% and 55% for the commonly used linear method and an exponential method, respectively. For high perfusion, an extension of the analytical method estimates SAR with less than 10% error. The analytical method is validated experimentally by showing that the temperature elevations predicted using the analytical method's SAR values determined for the entire 3D focal region agree well with the experimental temperature elevations in a HIFU-heated tissue-mimicking phantom. (paper)

  16. Sparse SAR imaging based on L1/2 regularization

    Institute of Scientific and Technical Information of China (English)

    ZENG JinShan; FANG Jian; XU ZongBen

    2012-01-01

    In this paper,a novel method for synthetic aperture radar (SAR) imaging is proposed.The approach is based on L1/2 regularization to reconstruct the scattering field,which optimizes a quadratic error term of the SAR observation process subject to the interested scene sparsity. Compared to the conventional SAR imaging technique,the new method implements SAR imaging effectively at much lower sampling rate than the Nyquist rate,and produces high-quality images with reduced sidelobes and increased resolution. Also,over the prevalent greedy pursuit and L1 regularization based SAR imaging methods,there are remarkable performance improvements of the new method.On one hand,the new method significantly reduces the number of measurements needed for reconstruction,as supported by a phase transition diagram study.On the other hand,the new method is more robust to the observation noise.These fundamental properties of the new method are supported and demonstrated both by simulations and real SAR data experiments.

  17. Surface displacement studies using differential SAR interferometry: an overview

    Science.gov (United States)

    Gupta, Sonal; Sajith V., K.; Arora, Manoj K.; Sharma, Mukut L.

    2006-12-01

    The differential SAR interferometry (DInSAR) has been increasing used to monitor ground surface displacements, which may be caused by various natural disasters such as earthquakes, landslides, mining activities, avalanches etc. Conventionally, these displacements were being estimated through field measurements, which are time consuming, hazardous and with data collected over few point locations. Since all the development and rehabilitation works after a natural disaster strikes is carried out on regional basis, any information at spatial level is advantageous in planning, management and monitoring activities. In recent years, the application of Differential SAR interferometry is gaining momentum to estimate the surface displacements at millimeter level accuracy. The displacement maps produced via this technique provide information at spatial level in the region thereby assisting in judicious developmental and planning works in an efficient and cost-effective manner. The aim of this paper is provide an overview of the use of Differential SAR Interferometry (DinSAR) technology for the study of surface displacements. As a case study, land subsidence occurred due to coal mining in Jharia coal fields, Jharkhand, have been estimated through this technique. All the procedural steps in implementing the approach based on DinSAR have been explained in a simplified manner.

  18. Canonical framework for multi-channel SAR-GMTI

    Institute of Scientific and Technical Information of China (English)

    Liu Congfeng; Liao Guisheng

    2008-01-01

    Synthetic aperture radar (SAR) systems have become an important tool for fine-resolution mapping and other remote sensing operations.The multi-channel SAR ground moving-target indication (GMTI) must process its data to produce not only the image of surveillance area but also the information of the ground moving-targets.The topic of moving-target detection in clutter has been extensively studied,and there are many methods that are used to detect moving targets,such as displaced phase center antenna (DPCA) method,along-track interfero-metric (ATI) phase,space-time adaptive processing (STAP),or some other metrics.A canonical framework is proposed that encompasses all the multi-channel SAR-GMT methods,namely,DPCA and ATI.The statistical test metric for multi-channel SAR-GMTI is established in a simple form,via the definition of the complex central Wishart distribution,to deduce the statistics of the test metric,and the probability distribution of the test metric for multichannel SAR-GMTI has the complex central Wishart distribution of 1×1 case,namely the x2 distribution.The theory foundation offers the possibility to construct the united multi-channel SAR-GMTI detector,and derives the constant false alarm rate (CFAR) detector tests for separating moving targets from clutter.

  19. ISRO's dual frequency airborne SAR pre-cursor to NISAR

    Science.gov (United States)

    Ramanujam, V. Manavala; Suneela, T. J. V. D.; Bhan, Rakesh

    2016-05-01

    The Indian Space Research Organisation (ISRO) and the National Aeronautics and Space Administration (NASA) have jointly embarked on NASA-ISRO Synthetic Aperture Radar (NISAR) operating in L-band and S-band, which will map Earth's surface every 12 days. As a pre-cursor to the NISAR mission, ISRO is planning an airborne SAR (L&S band) which will deliver NISAR analogue data products to the science community. ISRO will develop all the hardware with the aim of adhering to system design aspects of NISAR to the maximum extent possible. It is a fully polarimetric stripmap SAR and can be operated in single, dual, compact, quasi-quad and full polarimetry modes. It has wide incidence angle coverage from 24°-77° with swath coverage from 5.5km to 15 km. Apart from simultaneous imaging operations, this system can also operate in standalone L/S SAR modes. This system is planned to operate from an aircraft platform with nominal altitude of 8000meters. Antenna for this SAR will be rigidly mounted to the aircraft, whereas, motion compensation will be implemented in the software processor to generate data products. Data products for this airborne SAR will be generated in slant & ground range azimuth dimension and geocoded in HDF5/Geotiff formats. This airborne SAR will help to prepare the Indian scientific community for optimum utilization of NISAR data. In-order to collect useful science data, airborne campaigns are planned from end of 2016 onwards.

  20. Improved SAR Image Coregistration Using Pixel-Offset Series

    KAUST Repository

    Wang, Teng

    2014-03-14

    Synthetic aperture radar (SAR) image coregistration is a key procedure before interferometric SAR (InSAR) time-series analysis can be started. However, many geophysical data sets suffer from severe decorrelation problems due to a variety of reasons, making precise coregistration a nontrivial task. Here, we present a new strategy that uses a pixel-offset series of detected subimage patches dominated by point-like targets (PTs) to improve SAR image coregistrations. First, all potentially coherent image pairs are coregistered in a conventional way. In this step, we propose a coregistration quality index for each image to rank its relative “significance” within the data set and to select a reference image for the SAR data set. Then, a pixel-offset series of detected PTs is made from amplitude maps to improve the geometrical mapping functions. Finally, all images are resampled depending on the pixel offsets calculated from the updated geometrical mapping functions. We used images from a rural region near the North Anatolian Fault in eastern Turkey to test the proposed method, and clear coregistration improvements were found based on amplitude stability. This enhanced the fact that the coregistration strategy should therefore lead to improved InSAR time-series analysis results.

  1. TEC retrieval from spaceborne SAR data and its applications

    Science.gov (United States)

    Wang, Cheng; Zhang, Min; Xu, Zheng-Wen; Zhao, Hai-Sheng

    2014-10-01

    It is well known that the spaceborne synthetic aperture radar (SAR) at VHF-UHF band can be seriously affected by the ionosphere. Thus, the geophysical information of the ionosphere will be embedded in the low-frequency SAR echoes after they transverse the ionosphere. Correspondingly, the total electron content (TEC), a typical ionospheric information parameter, can be retrieved from the spaceborne SAR data. However, the existing dual-band techniques for TEC retrieval usually do not include consideration of multiple scattering effects caused by turbulent ionosphere, which plays an important role in the total path delay of signal under the strong fluctuation regimes. The result of TEC retrieval is therefore inaccurate and not applicable. Aiming at this issue, first, this paper analyzes the effects of regular background and the irregularity of electron density on SAR at L-band, and the theoretical formulation is given. Then, a triband path delay technique of TEC retrieval based on the SAR data is proposed. By using three path delays corresponding to three specific frequencies within the signal bandwidth, this technique can remove the errors of multiple scattering due to the irregularity, and a high accuracy resolution of TEC value therefore can be obtained. Meanwhile, the sensitivity of this technique is analyzed. Finally, compared with traditional dual-band technique, the numerical simulations show that the correction of SAR imaging based on triband technique is improved significantly. In addition, the resolution of reconstruction imaging using computerized ionospheric tomography performs significantly better based on the triband technique.

  2. Playback system designed for X-Band SAR

    International Nuclear Information System (INIS)

    SAR(Synthetic Aperture Radar) has extensive application because it is daylight and weather independent. In particular, X-Band SAR strip map, designed by Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, provides high ground resolution images, at the same time it has a large spatial coverage and a short acquisition time, so it is promising in multi-applications. When sudden disaster comes, the emergency situation acquires radar signal data and image as soon as possible, in order to take action to reduce loss and save lives in the first time. This paper summarizes a type of X-Band SAR playback processing system designed for disaster response and scientific needs. It describes SAR data workflow includes the payload data transmission and reception process. Playback processing system completes signal analysis on the original data, providing SAR level 0 products and quick image. Gigabit network promises radar signal transmission efficiency from recorder to calculation unit. Multi-thread parallel computing and ping pong operation can ensure computation speed. Through gigabit network, multi-thread parallel computing and ping pong operation, high speed data transmission and processing meet the SAR radar data playback real time requirement

  3. Forest stand structure from airborne polarimetric InSAR

    Science.gov (United States)

    Balzter, H.; Saich, P.; Luckman, A. J.; Skinner, L.; Grant, J.

    2002-01-01

    Interferometric SAR at short wavelengths can be used to retrieve stand height of forests. We evaluate the precision of tree height estimation from airborne single-pass interferometric E-SAR data at X-band VV polarisation and repeat-pass L-band polarimetric data. General yield class curves were used to estimate tree height from planting year, tree species and yield class data provided by the Forest Enterprise. The data were compared to tree height estimates from X-VV single-pass InSAR and repeat-pass polarimetric InSAR at L-band acquired by DLR's E-SAR during the SHAC campaign 2000. The effect of gap structure and incidence angle on retrieval precision of tree height from interferometric SAR is analysed. Appropriate correction methods to improve tree height retrieval are proposed. The coherent microwave model CASM is used with a Lindenmayer system tree model to simulate the observed underestimation of stand height in the presence of gaps.

  4. Evaluation of Polarimetric SAR Decomposition for Classifying Wetland Vegetation Types

    Directory of Open Access Journals (Sweden)

    Sang-Hoon Hong

    2015-07-01

    Full Text Available The Florida Everglades is the largest subtropical wetland system in the United States and, as with subtropical and tropical wetlands elsewhere, has been threatened by severe environmental stresses. It is very important to monitor such wetlands to inform management on the status of these fragile ecosystems. This study aims to examine the applicability of TerraSAR-X quadruple polarimetric (quad-pol synthetic aperture radar (PolSAR data for classifying wetland vegetation in the Everglades. We processed quad-pol data using the Hong & Wdowinski four-component decomposition, which accounts for double bounce scattering in the cross-polarization signal. The calculated decomposition images consist of four scattering mechanisms (single, co- and cross-pol double, and volume scattering. We applied an object-oriented image analysis approach to classify vegetation types with the decomposition results. We also used a high-resolution multispectral optical RapidEye image to compare statistics and classification results with Synthetic Aperture Radar (SAR observations. The calculated classification accuracy was higher than 85%, suggesting that the TerraSAR-X quad-pol SAR signal had a high potential for distinguishing different vegetation types. Scattering components from SAR acquisition were particularly advantageous for classifying mangroves along tidal channels. We conclude that the typical scattering behaviors from model-based decomposition are useful for discriminating among different wetland vegetation types.

  5. InSAR Scientific Computing Environment

    Science.gov (United States)

    Rosen, Paul A.; Sacco, Gian Franco; Gurrola, Eric M.; Zabker, Howard A.

    2011-01-01

    This computing environment is the next generation of geodetic image processing technology for repeat-pass Interferometric Synthetic Aperture (InSAR) sensors, identified by the community as a needed capability to provide flexibility and extensibility in reducing measurements from radar satellites and aircraft to new geophysical products. This software allows users of interferometric radar data the flexibility to process from Level 0 to Level 4 products using a variety of algorithms and for a range of available sensors. There are many radar satellites in orbit today delivering to the science community data of unprecedented quantity and quality, making possible large-scale studies in climate research, natural hazards, and the Earth's ecosystem. The proposed DESDynI mission, now under consideration by NASA for launch later in this decade, would provide time series and multiimage measurements that permit 4D models of Earth surface processes so that, for example, climate-induced changes over time would become apparent and quantifiable. This advanced data processing technology, applied to a global data set such as from the proposed DESDynI mission, enables a new class of analyses at time and spatial scales unavailable using current approaches. This software implements an accurate, extensible, and modular processing system designed to realize the full potential of InSAR data from future missions such as the proposed DESDynI, existing radar satellite data, as well as data from the NASA UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar), and other airborne platforms. The processing approach has been re-thought in order to enable multi-scene analysis by adding new algorithms and data interfaces, to permit user-reconfigurable operation and extensibility, and to capitalize on codes already developed by NASA and the science community. The framework incorporates modern programming methods based on recent research, including object-oriented scripts controlling legacy and

  6. Mitigating illumination gradients in a SAR image based on the image data and antenna beam pattern

    Science.gov (United States)

    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.

  7. Message concerning Severe Acute Respiratory Syndrome ("SARS")

    CERN Multimedia

    2003-01-01

    IMPORTANT REMINDER If you have just come back from one of the regions identified by the WHO as being infected with SARS, it is essential to monitor your state of health for ten days after your return. The syndrome manifests itself in the rapid onset of a high fever combined with respiratory problems (coughing, breathlessness, breathing difficulty). Should these signs appear, you must contact the CERN Medical Service as quickly as possible on number 73802 or 73186 during normal working hours, and the fire brigade at all other times on number 74444, indicating that you have just returned from one of the WHO-identified areas with recent local transmission.China: Beijing, Hong Kong (Special Administrative Region), Guangdong Province, Inner Mongolia, Shanxi Province, Tianjin ProvinceTaiwan:TaipeiMoreover, until further notice the CERN Management requests that all trips to these various regions of the world be reduced to a strict minimum and then only with the consent of the Division Leader concerned. Anyone comin...

  8. Applying target shadow models for SAR ATR

    Science.gov (United States)

    Papson, Scott; Narayanan, Ram M.

    2007-04-01

    Recent work has suggested that target shadows in synthetic aperture radar (SAR) images can be used effectively to aid in target classification. The method outlined in this paper has four steps - segmentation, representation, modeling, and selection. Segmentation is the process by which a smooth, background-free representation of the target's shadow is extracted from an image chip. A chain code technique is then used to represent the shadow boundary. Hidden Markov modeling is applied to sets of chain codes for multiple targets to create a suitable bank of target representations. Finally, an ensemble framework is proposed for classification. The proposed model selection process searches for an optimal ensemble of models based on various target model configurations. A five target subset of the MSTAR database is used for testing. Since the shadow is a back-projection of the target profile, some aspect angles will contain more discriminatory information then others. Therefore, performance is investigated as a function of aspect angle. Additionally, the case of multiple target looks is considered. The capability of the shadow-only classifier to enhance more traditional classification techniques is examined.

  9. Bandwidth requirements for fine resolution squinted SAR

    Energy Technology Data Exchange (ETDEWEB)

    DOERRY,ARMIN W.

    2000-03-01

    The conventional rule-of-thumb for Synthetic Aperture Radar is that an RF bandwidth of c/(2{rho}{sub r}) is required to image a scene at the desired slant-range resolution {rho}{sub r}, and perhaps a little more to account for window functions and sidelobe control. This formulation is based on the notion that the total bandwidth required is the same bandwidth that is required for a single pulse. What is neglected is that efficient processing of an entire synthetic aperture of pulses will often require different frequency content for each of the different pulses that makeup a synthetic aperture. Consequently, the total RF bandwidth required of a Synthetic Aperture Radar may then be substantially wider than the bandwidth of any single pulse. The actual RF bandwidth required depends strongly on flight geometry, owing to the desire for a radar to maintain a constant projection of the Fourier space collection surface onto the {omega}{sub y} axis. Long apertures required for fine azimuth resolution, and severe squint angles with steep depression angles may require total RF bandwidths well beyond the minimum bandwidth required of any single transmitted pulse, perhaps even by a factor of two or more. Accounting for this is crucial to designing efficient versatile high-performance imaging radars. This paper addresses how a data set conducive to efficient processing might increase the total RF bandwidth, and presents examples of how a fixed RF bandwidth might then limit SAR geometries.

  10. SARS plague: duty of care or medical heroism?

    Science.gov (United States)

    Tai, Dessmon Y H

    2006-05-01

    Severe acute respiratory syndrome (SARS) is a new infectious disease that emerged in mid- November 2002 in Guangdong, southern China. The global pandemic began in late February 2003 in Hong Kong. By the time SARS was declared contained on 5 July 2003 by the World Health Organization (WHO), it had afflicted 8096 patients in 29 countries. No other disease had had such a phenomenal impact on healthcare workers (HCWs), who formed about 21% of SARS patients. In Vietnam, Canada and Singapore, HCWs accounted for 57%, 43% and 41% of SAR patients, respectively. At the beginning of the outbreak, there was practically no information on this disease, which did not even have a name until 16 March 2003, except that it was infectious and could result in potentially fatal respiratory failure. Indeed, HCWs had lost their lives to SARS. Understandably, some HCWs refused to look after SARS patients or even resigned. Initially, much negative publicity was given to such HCWs. It was a very trying time for HCWs as many were also ostracised by the society which they served. They were perceived to be a potential source of infection in the community because of their contact with SARS patients, whom they risked their lives looking after. Subsequently, as we learnt more about the disease and educated the public about the plight of the frontline HCWs, the public gave the frontline HCWs tremendous support and even honoured them as heroes. Being in the medical profession, caring for patients is one of our expected responsibilities. On the other hand, as public citizens, HCWs have the right to resign when they feel that their responsibility to their families should take priority over that to their patients. As a result of this scourge, each HCW learnt to decide if caring for patients is their chosen profession and vocation. Many chose to live up the Hippocratic oath. PMID:16830007

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

    Science.gov (United States)

    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

  12. Tandem-L: Monitoring the Earth's Dynamics with InSAR and Pol-InSAR

    Science.gov (United States)

    Moriera, A.; Hajnsek, I.; Krieger, G.; Papathanassiou, K.; Eineder, M.; De Zan, F.; Younis, M.; Werner, M.

    2009-04-01

    Tandem-L is a German mission proposal for an innovative interferometric L-band radar mission that enables the systematic monitoring of dynamic Earth processes using advanced techniques and technologies. The mission is science driven aiming to provide a unique data set for climate and environmental research, geodynamics, hydrology and oceanography. Important application examples are global forest height and biomass inventories, measurements of Earth deformation due to tectonic processes and/or anthropogenic factors, observations of ice/glacier velocity field and 3-D structure changes, and the monitoring of ocean surface currents. The Tandem-L mission concept consists of two cooperating satellites flying in close formation. The Pol-InSAR and repeat-pass acquisition modes provide a unique data source to observe, analyse and quantify a wide range of mutually interacting processes in the bio-, litho-, hydro- and cryosphere. The systematic observation of these processes benefits from the high data acquisition capacity and the novel high-resolution wide-swath SAR imaging modes that combine digital beamforming with a large reflector antenna. This paper provides an overview of the Tandem-L mission concept and its main application areas.

  13. Detecting and monitoring UCG subsidence with InSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, R J; Foxall, W; Yang, X

    2012-03-23

    The use of interferometric synthetic aperture radar (InSAR) to measure surface subsidence caused by Underground Coal Gasification (UCG) is tested. InSAR is a remote sensing technique that uses Synthetic Aperture Radar images to make spatial images of surface deformation and may be deployed from satellite or an airplane. With current commercial satellite data, the technique works best in areas with little vegetation or farming activity. UCG subsidence is generally caused by roof collapse, which adversely affects UCG operations due to gas loss and is therefore important to monitor. Previous studies have demonstrated the usefulness of InSAR in measuring surface subsidence related to coal mining and surface deformation caused by a coal mining roof collapse in Crandall Canyon, Utah is imaged as a proof-of-concept. InSAR data is collected and processed over three known UCG operations including two pilot plants (Majuba, South Africa and Wulanchabu, China) and an operational plant (Angren, Uzbekistan). A clear f eature showing approximately 7 cm of subsidence is observed in the UCG field in Angren. Subsidence is not observed in the other two areas, which produce from deeper coal seams and processed a smaller volume. The results show that in some cases, InSAR is a useful tool to image UCG related subsidence. Data from newer satellites and improved algorithms will improve effectiveness.

  14. High-Level Performance Modeling of SAR Systems

    Science.gov (United States)

    Chen, Curtis

    2006-01-01

    SAUSAGE (Still Another Utility for SAR Analysis that s General and Extensible) is a computer program for modeling (see figure) the performance of synthetic- aperture radar (SAR) or interferometric synthetic-aperture radar (InSAR or IFSAR) systems. The user is assumed to be familiar with the basic principles of SAR imaging and interferometry. Given design parameters (e.g., altitude, power, and bandwidth) that characterize a radar system, the software predicts various performance metrics (e.g., signal-to-noise ratio and resolution). SAUSAGE is intended to be a general software tool for quick, high-level evaluation of radar designs; it is not meant to capture all the subtleties, nuances, and particulars of specific systems. SAUSAGE was written to facilitate the exploration of engineering tradeoffs within the multidimensional space of design parameters. Typically, this space is examined through an iterative process of adjusting the values of the design parameters and examining the effects of the adjustments on the overall performance of the system at each iteration. The software is designed to be modular and extensible to enable consideration of a variety of operating modes and antenna beam patterns, including, for example, strip-map and spotlight SAR acquisitions, polarimetry, burst modes, and squinted geometries.

  15. Camouflage effectiveness of static nets in SAR images

    Science.gov (United States)

    Jersblad, Johan; Larsson, Christer

    2015-10-01

    We present a methodology to determine the camouflage effectiveness of static nets in a SAR image. There is currently no common recognized methodology within the signature management community in this research topic. One step towards establishing a common methodology is to use a standardized target to be camouflaged. We use the STANdard Decoy for CAmouflage Materials (STANDCAM) target developed by the German Army, WTD 52, Oberjettenberg. An ISAR measurement of the STANDCAM with a camouflage configuration is acquired as the first step of the method. The ISAR data is then blended with SAR data acquired in field trials. In the final SAR image a contrast metric between the target and background is extracted. The contrast measure is then the measure of the camouflage effectiveness. As an example of result we present ISAR measurements and determine the camouflage effectiveness in a SAR image using SAR blending for static nets with different electrical conductivity and design. This methodology presents a measure to determine the effectiveness of a static net on the STANDCAM target.

  16. Noise Removal in SAR Images using Orthonormal Ridgelet Transform

    Directory of Open Access Journals (Sweden)

    A. Ravi,

    2015-05-01

    Full Text Available Development in the field of image processing for reducing speckle noise from digital images/satellite images is a challenging task for image processing applications. Previously many algorithms were proposed to de-speckle the noise in digital images. Here in this article we are presenting experimental results on de-speckling of Synthetic Aperture RADAR (SAR images. SAR images have wide applications in remote sensing and mapping the surfaces of all planets. SAR can also be implemented as "inverse SAR" by observing a moving target over a substantial time with a stationary antenna. Hence denoising of SAR images is an essential task for viewing the information. Here we introduce a transformation technique called ―Ridgelet‖, which is an extension level of wavelet. Ridgelet analysis can be done in the similar way how wavelet analysis was done in the Radon domain as it translates singularities along lines into point singularities under different frequencies. Simulation results were show cased for proving that proposed work is more reliable than compared to other despeckling processes, and the quality of de-speckled image is measured in terms of Peak Signal to Noise Ratio and Mean Square Error.

  17. Integration of InSAR and GPS for hydraulic engineering

    Institute of Scientific and Technical Information of China (English)

    HE; XiuFeng; LUO; HaiBin; HUANG; QiHuan; HE; Min

    2007-01-01

    Interferometric synthetic aperture radar (InSAR) is a potential earth observation approach,and it has been demonstrated to have a variety of applications in measuring ground movement,urban subsidence and landslides.Currently InSAR provides the ability to map accurate DEM and measure ground deformation to sub-centimeter accuracy.However,many factors affect InSAR to measure ground movement since dam constructions are built in a large scale area with a complicated climate and unstable geology.This paper discusses potential applications of integrated InSAR and GPS to monitor a large-scale ground movement due to hydropower developments.The integration of InSAR and GPS can provide a cost-effective means for monitoring deformation of hydropower developments.Moreover,two novel methods,both the improved spatial interpolating method and estimation of 3D surface motion velocities method,are proposed and the experimental results and analysis are given in this paper.

  18. Determining Titan surface topography from Cassini SAR data

    Science.gov (United States)

    Stiles, Bryan W.; Hensley, Scott; Gim, Yonggyu; Bates, David M.; Kirk, Randolph L.; Hayes, Alex; Radebaugh, Jani; Lorenz, Ralph D.; Mitchell, Karl L.; Callahan, Philip S.; Zebker, Howard; Johnson, William T.K.; Wall, Stephen D.; Lunine, Jonathan I.; Wood, Charles A.; Janssen, Michael; Pelletier, Frederic; West, Richard D.; Veeramacheneni, Chandini

    2009-01-01

    A technique, referred to as SARTopo, has been developed for obtaining surface height estimates with 10 km horizontal resolution and 75 m vertical resolution of the surface of Titan along each Cassini Synthetic Aperture Radar (SAR) swath. We describe the technique and present maps of the co-located data sets. A global map and regional maps of Xanadu and the northern hemisphere hydrocarbon lakes district are included in the results. A strength of the technique is that it provides topographic information co-located with SAR imagery. Having a topographic context vastly improves the interpretability of the SAR imagery and is essential for understanding Titan. SARTopo is capable of estimating surface heights for most of the SAR-imaged surface of Titan. Currently nearly 30% of the surface is within 100 km of a SARTopo height profile. Other competing techniques provide orders of magnitude less coverage. We validate the SARTopo technique through comparison with known geomorphological features such as mountain ranges and craters, and by comparison with co-located nadir altimetry, including a 3000 km strip that had been observed by SAR a month earlier. In this area, the SARTopo and nadir altimetry data sets are co-located tightly (within 5-10 km for one 500 km section), have similar resolution, and as expected agree closely in surface height. Furthermore the region contains prominent high spatial resolution topography, so it provides an excellent test of the resolution and precision of both techniques.

  19. Targeted Radiosensitization by the Chk1 Inhibitor SAR-020106

    Energy Technology Data Exchange (ETDEWEB)

    Borst, Gerben R., E-mail: g.borst@nki.nl [The Institute of Cancer Research, London (United Kingdom); Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); McLaughlin, Martin; Kyula, Joan N.; Neijenhuis, Sari; Khan, Aadil; Good, James; Zaidi, Shane [The Institute of Cancer Research, London (United Kingdom); Powell, Ned G. [HPV Research Group, School of Medicine, Cardiff University, Cardiff (United Kingdom); Meier, Pascal; Collins, Ian; Garrett, Michelle D. [The Institute of Cancer Research, London (United Kingdom); Verheij, Marcel [Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Amsterdam (Netherlands); Harrington, Kevin J. [The Institute of Cancer Research, London (United Kingdom)

    2013-03-15

    Purpose: To explore the activity of a potent Chk1 inhibitor (SAR-020106) in combination with radiation. Methods and Materials: Colony and mechanistic in vitro assays and a xenograft in vivo model. Results: SAR-020106 suppressed-radiation-induced G{sub 2}/M arrest and reduced clonogenic survival only in p53-deficient tumor cells. SAR-020106 promoted mitotic entry following irradiation in all cell lines, but p53-deficient cells were likely to undergo apoptosis or become aneuploid, while p53 wild-type cells underwent a postmitotic G{sub 1} arrest followed by subsequent normal cell cycle re-entry. Following combined treatment with SAR-020106 and radiation, homologous-recombination-mediated DNA damage repair was inhibited in all cell lines. A significant increase in the number of pan-γH2AX-staining apoptotic cells was observed only in p53-deficient cell lines. Efficacy was confirmed in vivo in a clinically relevant human head-and-neck cell carcinoma xenograft model. Conclusion: The Chk1 inhibitor SAR-020106 is a potent radiosensitizer in tumor cell lines defective in p53 signaling.

  20. Flexible T/R Modules for Large-Aperture, Space-Based SAR Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a need for electronically-steerable, space-deployable SAR antenna arrays which impose minimal weight burden on the vehicles that place them into orbit. SAR...

  1. The SARS-unique domain (SUD of SARS coronavirus contains two macrodomains that bind G-quadruplexes.

    Directory of Open Access Journals (Sweden)

    Jinzhi Tan

    2009-05-01

    Full Text Available Since the outbreak of severe acute respiratory syndrome (SARS in 2003, the three-dimensional structures of several of the replicase/transcriptase components of SARS coronavirus (SARS-CoV, the non-structural proteins (Nsps, have been determined. However, within the large Nsp3 (1922 amino-acid residues, the structure and function of the so-called SARS-unique domain (SUD have remained elusive. SUD occurs only in SARS-CoV and the highly related viruses found in certain bats, but is absent from all other coronaviruses. Therefore, it has been speculated that it may be involved in the extreme pathogenicity of SARS-CoV, compared to other coronaviruses, most of which cause only mild infections in humans. In order to help elucidate the function of the SUD, we have determined crystal structures of fragment 389-652 ("SUD(core" of Nsp3, which comprises 264 of the 338 residues of the domain. Both the monoclinic and triclinic crystal forms (2.2 and 2.8 A resolution, respectively revealed that SUD(core forms a homodimer. Each monomer consists of two subdomains, SUD-N and SUD-M, with a macrodomain fold similar to the SARS-CoV X-domain. However, in contrast to the latter, SUD fails to bind ADP-ribose, as determined by zone-interference gel electrophoresis. Instead, the entire SUD(core as well as its individual subdomains interact with oligonucleotides known to form G-quadruplexes. This includes oligodeoxy- as well as oligoribonucleotides. Mutations of selected lysine residues on the surface of the SUD-N subdomain lead to reduction of G-quadruplex binding, whereas mutations in the SUD-M subdomain abolish it. As there is no evidence for Nsp3 entering the nucleus of the host cell, the SARS-CoV genomic RNA or host-cell mRNA containing long G-stretches may be targets of SUD. The SARS-CoV genome is devoid of G-stretches longer than 5-6 nucleotides, but more extended G-stretches are found in the 3'-nontranslated regions of mRNAs coding for certain host-cell proteins

  2. High-precision Motion Compensation Method Based on the Subaperture Envelope Error Correction for SAR

    OpenAIRE

    Tian Xue; Liang Xing-dong; Li Yan-lei; Dong Yong-wei

    2015-01-01

    Small size, light weight, and low power are presently the directions in SAR development. The microSAR platform is small and light, which results in track deviations because of air flow. The large motion error strongly affects the quality of SAR images. Therefore, high-precision motion compensation is important to SAR image processing. Motion error results in phase and envelope errors. Traditional motion compensation algorithms often ignore the space variance of the envelope error. When the mo...

  3. A Coordination Model of Gene Sequences for SARS-CoV and its Receptor

    Institute of Scientific and Technical Information of China (English)

    SHAO Shi-huang; DAI Hua; GAO Lei; HUANG Ying-Song; HUANG Zhen-de; DING Yong-sheng

    2004-01-01

    A Z curve-based coordination model of genome sequences for the interaction of the SARS coronavirus (SARS-CoV) with its receptor, angiotensin-converting enzyme 2 (ACE2) is proposed. The model provides a novel, intuitive tool for visualizing and analyzing DNA sequences of SARS. It will be useful to the analysis of SARS-CoV in lab detection. Also, it can be used as a solution to other studies in bioinformatics field.

  4. Estimation of the Temporal Evolution of the Deformation Using Airborne Differential SAR Interferometry

    OpenAIRE

    Prats, Pau; Reigber, Andreas; Mallroqui, Jordi J.; Scheiber, Rolf; Moreira, Alberto

    2008-01-01

    This paper presents airborne differential SAR interferometry results using a stack of 14 images, which were acquired by the Experimental SAR (E-SAR) system of the German Aerospace Center (DLR) during a time span of two and a half hours. An advanced differential technique is used to retrieve the error in the digital elevation model and the temporal evolution of the deformation for every coherent pixel in the image. The two main limitations in airborne SAR processing are analyzed, namely the ex...

  5. A comparative epidemiologic analysis of SARS in Hong Kong, Beijing and Taiwan

    OpenAIRE

    Chang Chiu-Wen; Donnelly Christl A; Tsang Thomas; Ho Lai-Ming; Chen Chang-Hsun; Cowling Benjamin J; Hsiung C Agnes; Lau Eric HY; Leung Gabriel M

    2010-01-01

    Abstract Background The 2002-2003 Severe Acute Respiratory Syndrome (SARS) outbreak infected 8,422 individuals leading to 916 deaths around the world. However, there have been few epidemiological studies of SARS comparing epidemiologic features across regions. The aim of this study is to identify similarities and differences in SARS epidemiology in three populations with similar host and viral genotype. Methods We present a comparative epidemiologic analysis of SARS, based on an integrated da...

  6. Study on Zero-Doppler Centroid Control for GEO SAR Ground Observation

    OpenAIRE

    2014-01-01

    In geosynchronous Earth orbit SAR (GEO SAR), Doppler centroid compensation is a key step for imaging process, which could be performed by the attitude steering of a satellite platform. However, this zero-Doppler centroid control method does not work well when the look angle of radar is out of an expected range. This paper primarily analyzes the Doppler properties of GEO SAR in the Earth rectangular coordinate. Then, according to the actual conditions of the GEO SAR ground observation, the eff...

  7. DE-SPECKLING OF SAR IMAGES BASED ON OPTIMAL BASIS WAVELET VIA PATCH ORDERING

    OpenAIRE

    Anakha Satheesh P*, Dr. D. Loganathan

    2016-01-01

    Synthetic Aperture Radar (SAR) technology has mainly used for capturing high quality images from higher altitudes. SAR imagery has become an important application over optical satellite imagery because of its ability to operate in any whether condition. The SAR image acquired via coherent imaging are associated with a noise called speckle noise, which is multiplicative in nature. The presence of speckle noise degrades the quality of SAR image then leads to loss of crucial information. So it h...

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

    Science.gov (United States)

    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.

  9. THE EFFECT OF IMU INACCURACIES ON AIRBORNE SAR IMAGING

    Institute of Scientific and Technical Information of China (English)

    Mao Yongfei; Xiang Maosheng; Wei Lideng; Han Songtao

    2011-01-01

    When using motion compensation approaches based on the measurement of motion sensors,the residual uncompensated motion errors due to measurement instrument inaccuracies contribute to phase errors and hence degrade Synthetic Aperture Radar (SAR) images.This paper presents a model to compute the phase error caused by Inertial Measurement Unit (IMU) measurement inaccuracies.By analyzing SAR motion compensation method and the effect of lever arm,this model derives the contribution of each term of IMU inaccuracies towards the residual uncompensated motion errors and provides a method to calculate each order of the residual phase error.According to the model,computed results of the airborne X-band SAR system with POS AV510 accord closely with the actual image quality.

  10. Expression and Purification of SARS Coronavirus Membrane Protein

    Institute of Scientific and Technical Information of China (English)

    戴五星; 雷明军; 吴少庭; 陈智浩; 梁靓; 潘晖榕; 秦莉; 高士同; 袁仕善; 张仁利

    2004-01-01

    To construct a recombinant plasmid Pet23a-M, the gene encoding severe acute respiratory syndrome (SARS) coronavirus membrane protein was amplified by RT-PCR and cloned into the expression plasmid Pet23a. Results of restriction endonuclease analysis, PCR detection and DNA sequencing analysis revealed that the cloned DNA sequence was the same as that reported. The re combinants were transformed into Escherichia coli (E. Coli) BL21 (DE3) and induced by Isopropylβ-D-thiogalactopyranoside (IPTG). The expression of 27 kD (1 kD=0. 992 1 ku) protein was detected by SDS-PAGE and pured by metal chelated chromatography. Results of Western-blot showed that this expressed protein could react with antibodies in sera of SARS patients during convalescence. This provided the basis for the further study on SARS virus vaccine and diagnostic agents.

  11. Parallel algorithms for high-speed SAR processing

    Science.gov (United States)

    Mallorqui, Jordi J.; Bara, Marc; Broquetas, Antoni; Wis, Mariano; Martinez, Antonio; Nogueira, Leonardo; Moreno, Victoriano

    1998-11-01

    The mass production of SAR products and its usage on monitoring emergency situations (oil spill detection, floods, etc.) requires high-speed SAR processors. Two different parallel strategies for near real time SAR processing based on a multiblock version of the Chirp Scaling Algorithm (CSA) have been studied. The first one is useful for small companies that would like to reduce computation times with no extra investment. It uses a cluster of heterogeneous UNIX workstations as a parallel computer. The second one is oriented to institutions, which have to process large amounts of data in short times and can afford the cost of large parallel computers. The parallel programming has reduced in both cases the computational times when compared with the sequential versions.

  12. SAR Imagery Segmentation by Statistical Region Growing and Hierarchical Merging

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela Mayumi; Carvalho, E.A.; Medeiros, F.N.S.; Martins, C.I.O.; Marques, R.C.P.; Oliveira, I.N.S.

    2010-05-22

    This paper presents an approach to accomplish synthetic aperture radar (SAR) image segmentation, which are corrupted by speckle noise. Some ordinary segmentation techniques may require speckle filtering previously. Our approach performs radar image segmentation using the original noisy pixels as input data, eliminating preprocessing steps, an advantage over most of the current methods. The algorithm comprises a statistical region growing procedure combined with hierarchical region merging to extract regions of interest from SAR images. The region growing step over-segments the input image to enable region aggregation by employing a combination of the Kolmogorov-Smirnov (KS) test with a hierarchical stepwise optimization (HSWO) algorithm for the process coordination. We have tested and assessed the proposed technique on artificially speckled image and real SAR data containing different types of targets.

  13. Using support vector classification for SAR of fentanyl derivatives

    Institute of Scientific and Technical Information of China (English)

    Ning DONG; Wen-cong LU; Nian-yi CHEN; You-cheng ZHU; Kai-xian CHEN

    2005-01-01

    Aim: To discriminate between fentanyl derivatives with high and low activities.Methods: The support vector classification (SVC) method, a novel approach,was employed to investigate structure-activity relationship (SAR) of fentanyl derivatives based on the molecular descriptors, which were quantum parameters including △E [energy difference between highest occupied molecular orbital energy (HOMO) and lowest empty molecular orbital energy (LUMO)], MR(molecular refractivity) and Mr (molecular weight). Results: By using leave-oneout cross-validation test, the accuracies of prediction for activities of fentanyl derivatives in SVC, principal component analysis (PCA), artificial neural network (ANN) and K-nearest neighbor (KNN) models were 93%, 86%, 57%, and 71%, respectively. The results indicated that the performance of the SVC model was better than those of PCA, ANN, and KNN models for this data. Conclusion:SVC can be used to investigate SAR of fentanyl derivatives and could be a promising tool in the field of SAR research.

  14. Segment-based change detection for polarimetric SAR data

    DEFF Research Database (Denmark)

    Skriver, Henning; Nielsen, Allan Aasbjerg; Conradsen, Knut

    2006-01-01

    1. BACKGROUND Change detection is a very important application of Earth observation data. A number of different applications relies on robust and accurate change detection from such data. Update of topographic maps is, for instance, a very important process for mapping agencies to be able to...... polarimetric synthetic aperture radar (SAR) backscatter data is the so-called covariance matrix data format. For each pixel this consists of a 3×3 Hermitian, positive definite matrix which follows a complex Wishart distribution. Based on this distribution a test statistic for equality of two such matrices and...... thinned image. This method relies primarily on a robust edge detector, which preferably provides a constant false alarm rate. For single-channel SAR images this is fulfilled by the ratio edge detector, and for polarimetric SAR data, an edge detector based on the above mentioned test statistic fulfils this...

  15. Feature Extraction and Classification of Oil Spills in SAR Imagery

    Directory of Open Access Journals (Sweden)

    Radhika V

    2011-09-01

    Full Text Available Synthetic Aperture RADAR (SAR imaging system is used to monitor the marine system. Oil spill pollution plays a significant role in damaging marine ecosystem. One main advantages of SAR is that it can generate imagery under all weather conditions. In a SAR image dark spots can be generated by number of phenomena. The dark spots may be of algae, low wind areas, coastal areas and oil spills. The detected dark spots are then classified based on the features. The features of dark spot are extracted to discriminate oil spill from look-alikes. The textural and statistical features are extracted and analyzed for oil spill identification. This paper discusses about the different feature extraction and classification method for oil spill detection and their preliminary results.

  16. Restoration of polarimetric SAR images using simulated annealing

    DEFF Research Database (Denmark)

    Schou, Jesper; Skriver, Henning

    2001-01-01

    Filtering synthetic aperture radar (SAR) images ideally results in better estimates of the parameters characterizing the distributed targets in the images while preserving the structures of the nondistributed targets. However, these objectives are normally conflicting, often leading to a filtering...... approach favoring one of the objectives. An algorithm for estimating the radar cross-section (RCS) for intensity SAR images has previously been proposed in the literature based on Markov random fields and the stochastic optimization method simulated annealing. A new version of the algorithm is presented...... applicable to multilook polarimetric SAR images, resulting in an estimate of the mean covariance matrix rather than the RCS. Small windows are applied in the filtering, and due to the iterative nature of the approach, reasonable estimates of the polarimetric quantities characterizing the distributed targets...

  17. Distribution-based CFAR detectors in SAR images

    Institute of Scientific and Technical Information of China (English)

    Gan Rongbing; Wang Jianguo

    2006-01-01

    As traditional two-parameter constant false alarm rate (CFAR) target detection algorithms in SAR images ignore target distribution, their performances are not the best or near best. As the resolution of SAR images increases, small targets present more pixels in SAR images. So the target distribution is of much significance. Distribution-based CFAR detection algorithm is presented. We unite the pixels around the test cell, and estimate the distribution of test cell by them. Generalized Likelihood Ratio Test (GLRT) is used to deduce the detectors. The performance of the distribution-based CFAR (DBCFAR) detectors is analyzed theoretically. False alarms of DBCFAR detection are fewer than those of CFAR at the same detection rate. Finally experiments are done and the results show the performance of DBCFAR is out of conventional CFAR. False alarms of DBCFAR detection are concentrated while those of CFAR detection are dispersive.

  18. Ensemble polarimetric SAR image classification based on contextual sparse representation

    Science.gov (United States)

    Zhang, Lamei; Wang, Xiao; Zou, Bin; Qiao, Zhijun

    2016-05-01

    Polarimetric SAR image interpretation has become one of the most interesting topics, in which the construction of the reasonable and effective technique of image classification is of key importance. Sparse representation represents the data using the most succinct sparse atoms of the over-complete dictionary and the advantages of sparse representation also have been confirmed in the field of PolSAR classification. However, it is not perfect, like the ordinary classifier, at different aspects. So ensemble learning is introduced to improve the issue, which makes a plurality of different learners training and obtained the integrated results by combining the individual learner to get more accurate and ideal learning results. Therefore, this paper presents a polarimetric SAR image classification method based on the ensemble learning of sparse representation to achieve the optimal classification.

  19. Sparsity-driven autofocus for multipass SAR tomography

    Science.gov (United States)

    Muirhead, F.; Mulgrew, B.; Woodhouse, I. H.; Greig, D.

    2015-10-01

    Synthetic aperture radar (SAR) systems produce high resolution, two dimensional imaging of areas of environmental interest. SAR interferometry and tomography enables these techniques to extend to three dimensional imaging by exploiting multiple SAR images with diversity in space and time. These techniques require accurate phase information over multiple images as the data is extremely sensitive to deviations from the reference track, therefore to enable interferometry and tomography an accurate autofocus solution is required. This paper investigates phase errors resulting from navigational uncertainties in multipass spotlight SAR imaging and uses techniques from the field of compressive sensing to achieve an autofocus solution. The proposed algorithm builds on previous autofocus work by expanding it to the multipass case and jointly recovers phase errors for all images simultaneously, making it extremely useful for interferometry and tomography techniques. The algorithm described uses pixels that are stable in all SAR images to gain an autofocus solution as these are the pixels that are the focus for analysis using tomography. This is unlike conventional autofocus, which just works on an image-by-image basis. The tools of compressive sensing can be used to concurrently select pixels for bright image elements that are stable and coherent over all images, as these pixels are sparse in the image domain, and calculate the phase errors present in each pass. Using the multipass data after autofocus, height distributions for scatterers in single pixels are determined for simulated forest scenes at X-band. The performance of the autofocus algorithm is examined through numerical simulations and is also applied to real data collected from Selex ES's airborne, X-band, experimental SAR system. The experimental results demonstrate that the algorithm effectively achieves an autofocus solution. By finding the vertical distribution of two scatterers in a single pixel over

  20. Integrating interferometric SAR data with levelling measurements of land subsidence using geostatistics

    NARCIS (Netherlands)

    Zhou, Y.; Stein, A.; Molenaar, M.

    2003-01-01

    Differential Synthetic Aperture Radar (SAR) interferometric (D-InSAR) data of ground surface deformation are affected by several error sources associated with image acquisitions and data processing. In this paper, we study the use of D-InSAR for quantifying land subsidence due to groundwater extract

  1. Scattering Mechanism Extraction by a Modified Cloude-Pottier Decomposition for Dual Polarization SAR

    Directory of Open Access Journals (Sweden)

    Kefeng Ji

    2015-06-01

    Full Text Available Dual polarization is a typical operational mode of polarimetric synthetic aperture radar (SAR. However, few studies have considered the scattering mechanism extraction of dual-polarization SARs. A modified Cloude-Pottier decomposition is proposed to investigate the performance of the scattering mechanism extraction of dual-polarization SARs. It is theoretically demonstrated that only HH-VV SAR can discriminate the three canonical scattering mechanisms from an isotropic surface, horizontal dipole, and isotropic dihedral. Various experiments are conducted using 21 scenes from real datasets acquired by AIRSAR, Convair-580 SAR, EMISAR, E-SAR, Pi-SAR, and RADARSAT-2. Division of the dual-polarization H-α plane is experimentally obtained. The lack of cross-polarization induces the diffusion of scattering mechanisms and their overlap in the HH-VV H-α plane. However, the performance of HH-VV SAR for extracting scattering mechanisms is acceptable. Thus, HH-VV SAR is a suitable alternative to full-polarization SAR in certain cases. Meanwhile, the extraction performance of the other two dual-polarization SARs is badly degraded due to the lack of co-polarization. Therefore, HH-HV and HV-VV SARs cannot effectively extract the scattering mechanisms in the H-α plane.

  2. Soil moisture retrieval using the Danish L- & C-band polarimetric SAR

    DEFF Research Database (Denmark)

    JIANKANG, JI; Keur, Peter van der; Thomsen, Anton; Skriver, Henning

    Danish polarimetric SAR data have been applied to estimate soil moisture (SM). The preliminary results evaluated with the L- and C-band SAR data acquired at the Danish test site Foulum during a number of missions in 1994 and 1995 are presented. In situ data have been collected during the SAR miss...

  3. Change detection in a time series of polarimetric SAR images

    DEFF Research Database (Denmark)

    Skriver, Henning; Nielsen, Allan Aasbjerg; Conradsen, Knut

    a certain point can be used to detect at which points changes occur in the time series. [1] T. W. Anderson, An Introduction to Multivariate Statistical Analysis, John Wiley, New York, third edition, 2003. [2] K. Conradsen, A. A. Nielsen, J. Schou, and H. Skriver, “A test statistic in the complex...... to the complex Wishart distribution and demonstrate its application to change detection in truly multi-temporal, polarimetric SAR data. Results will be shown that demonstrate the difference between applying to time series of polarimetric SAR images, pairwise comparisons or the new omnibus test...

  4. Mesura de deformacions mitjançant GB-SAR

    OpenAIRE

    Monfort Codinach, Marta

    2014-01-01

    El present treball es centra en l’ús d’una tècnica de teledetecció terrestre basada en tecnologia Radar (GB-SAR) per la mesura de desplaçaments del terreny. El treball consta de dues parts principals: principis bàsics de la tècnica GB-SAR, descripció de dos procediments diferents per explotar les seves dades per la mesura de deformacions i, finalment, processat de les dades obtingudes sobre tres casos d’aplicació diferents. En aquest context, el treball ha estat enfocat a la co...

  5. 利用高分辨率聚束模式TerraSAR-X影像的PSInSAR监测地表变形%Monitoring Land Deformation Using PSInSAR with TerraSAR-X High Resolution Spotlight SAR Images

    Institute of Scientific and Technical Information of China (English)

    李永生; 张景发; 罗毅; 姜文亮

    2012-01-01

    利用20景于2010-03~2010-11期间采集的高分辨率聚束(1m分辨率)模式的TerraSAR-X SAR数据,采用永久散射体干涉测量技术(PSInSAR)获取了西藏羊八井地区由地热电站开采地下水引起的地面沉降。结果显示,羊八井地热电站周边及地热开采井地区在2010年期间的地面沉降速率最大达到25mm·a-1,而盆地其他地区的地面平均沉降速率为1mm·a-1。将其与ASAR获取的平均沉降速率结果对比,两者的相关性达到了0.76,这说明TerraSAR-X高分辨率SAR数据不仅可以提供高密度PS点,而且更好地体现了散射体的细节变化和微量位移情况。%Persistent scatterer InSAR was used to detect surface subsidence in the the Yangbajing geothermal power plant due to extraction of ground water with area aroun twent resolution TerraSAR-X spotlight SAR images collected between March and November y hig 2010 d h The results suggest that land subsidence in the areas of geothermal wells is up to 25 mm · a^-1 whilst the subsidence in the basin is less than 1 mm · a^- 1. And the correlation between TerraSAR-X and ASAR derived mean velocities is 0.76. TerraSAR-X high resolution spot- light SAR images can provide higher density of PS points than ASAR data, and also can re- veal the detail change and micro-displacement in a single ground object.

  6. Edge Detection Algorithm of SAR Images with Wedgelet Filter

    Institute of Scientific and Technical Information of China (English)

    REN Chao; WU Si-liang; JIAO Li-cheng

    2008-01-01

    Based on the analysis of the characteristics of synthetic aperture radar(SAR)images,a new edge detection method is proposed.The wedgelet transform is introduced into the area of SAR image speckle reduction for it can provide a nearly optimal representation for images in the horizon class.The wedgelet filter has good ability in keeping edge and speckle reduction.Then,a ratio edge detector is applied after a process of speckle reduction.The experimental results show that the method outperforms substantially others visually.

  7. Extraction of water and flood areas from SAR data

    OpenAIRE

    Hahmann, Thomas; Martinis, Sandro; Twele, André; Roth, Achim; Buchroithner, Manfred

    2008-01-01

    Medium resolution SAR satellite data have been widely used for water and flood mapping in recent years. Since 2007 high resolution radar data with up to 1 m pixel spacing of the TerraSAR-X satellite are operationally avail-able. The improved ground resolution of the system offers enormous potential for water detection. However, im-age analysis gets more challenging due to the large amount of image objects that are visible in the data. Water body detection methods are reviewed with regard to t...

  8. Simulation Study on SAR Images of the Oceanic Internal Waves

    Institute of Scientific and Technical Information of China (English)

    Jin-song CHONG; Fei LI; Yue OUYANG

    2010-01-01

    Based on the research of Lynett and Liu,the horizontal fully two-dimensional,depth-integrated model for the internal wave propagation is re-deduced.By combining this model with the M4S model,the propagation process of the internal waves is simulated in Synthetic Aperture Radar (SAR) images.The simulation results clearly show the bottom effects during the propagation such as fission and isobaths-parallelized propagation direction.This simulation procedure can lay the foundation for the quantitative interaretation of internal waves from fully two-dimensional SAR images.

  9. Residents Look Forward to New Lease on Life Post SARS

    Institute of Scientific and Technical Information of China (English)

    JessyZhang

    2003-01-01

    A new craze has taken over Beijing: people of all ages can be found playing badminton on the sidewalks, in parks and virtually any open space theycan find. Thanks to SARS, taking up outdoor sports seems to be a hobby that is high on everyone's agenda. This is of course, just one small positive impact of SARS. After weathering the disaster, a few silver linings are emerging in the country's social life, economy and even administrative governance as the Eastern giant struggles to get on its feet.

  10. Effect of beam-pointing errors on bistatic SAR imaging

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The purpose is to conduct a research in the energy variation of echo wave and the imaging effect caused by the aero bistatic SAR pointing errors.Based on the moving geometry configuration of aero bistatic SAR,a model of beam pointing errors is built.Based on this,the azimuth Doppler frequency center estimation caused by these errors and the limitation to the beam pointing synchronization error are studied,and then the imaging result of different errors are analyzed.The computer's simulations are provided to prove the validity of the above analysis.

  11. Imaging Algorithm for Bistatic SAR Based on GNSS Signal

    Directory of Open Access Journals (Sweden)

    Tian Wei-ming

    2013-03-01

    Full Text Available In this paper imaging processing method for Bistatic Synthetic Aperture Radar (BiSAR utilizing navigation satellite is investigated. Considering the special problems of using Global Navigation Satellite System (GNSS signal to form SAR image, direct signal is used to estimate range migration parameters and range migration is corrected in azimuth time domain. Doppler sensitivity of phase-coded signal was solved by Doppler compensation. Through fitting the Doppler phase history with high-order polynomial, Doppler phase history is accurately approximated and azimuth compression is implemented by de-chirp processing. Through simulation and experimental data processing, the proposed method is verified.

  12. Performance evaluation of the JPL interim digital SAR processor

    Science.gov (United States)

    Wu, C.; Barkan, B.; Curlander, J.; Jin, M.; Pang, S.

    1983-01-01

    The performance of the Interim Digital SAR Processor (IDP) was evaluated. The IDP processor was originally developed for experimental processing of digital SEASAT SAR data. One phase of the system upgrade which features parallel processing in three peripheral array processors, automated estimation for Doppler parameters, and unsupervised image pixel location determination and registration was executed. The method to compensate for the target range curvature effect was improved. A four point interpolation scheme is implemented to replace the nearest neighbor scheme used in the original IDP. The processor still maintains its fast throughput speed. The current performance and capability of the processing modes now available on the IDP system are updated.

  13. Microstrip antenna for polarimetric C-band SAR

    DEFF Research Database (Denmark)

    Granholm, Johan; Woelders, Kim; Dich, Mikael;

    1994-01-01

    The paper outlines the design and the measured performance of a 224-element dual-linearly polarized microstrip array antenna with low cross-polarization. The array is currently being flown on the Danish high-resolution polarimetric C-band synthetic aperture radar (SAR)......The paper outlines the design and the measured performance of a 224-element dual-linearly polarized microstrip array antenna with low cross-polarization. The array is currently being flown on the Danish high-resolution polarimetric C-band synthetic aperture radar (SAR)...

  14. Scale transform algorithm used in FMCW SAR data processing

    Institute of Scientific and Technical Information of China (English)

    Jiang Zhihong; Kan Huangfu; Wan Jianwei

    2007-01-01

    The frequency-modulated continuous-wave (FMCW) synthetic aperture radar (SAR) is a light-weight,cost-effective, high-resolution imaging radar, which is suitable for a small flight platform. The signal model is derived for FMCW SAR used in unmanned aerial vehicles (UAV) reconnaissance and remote sensing. An appropriate algorithm is proposed. The algorithm performs the range cell migration correction (RCMC) for continuous nonchirped raw data using the energy invariance of the scaling of a signal in the scale domain. The azimuth processing is based on step transform without geometric resampling operation. The complete derivation of the algorithm is presented. The algorithm performance is shown by simulation results.

  15. Internal Calibration of HJ-1-C Satellite SAR System

    Directory of Open Access Journals (Sweden)

    Yang Zhen

    2014-06-01

    Full Text Available The HJ-1-C satellite is a Synthetic Aperture Radar (SAR satellite of a small constellation for environmental and disaster monitoring. At present, it is in orbit and working well. The SAR system uses a mesh reflector antenna and centralized power amplifier, and has an internal calibration function in orbit. This study introduces the internal calibration modes and signal paths. The design and realization of the internal calibrator are discussed in detail. Finally, the internal calibration data acquired in orbit are also analyzed.

  16. The Danish real-time SAR processor: first results

    DEFF Research Database (Denmark)

    Dall, Jørgen; Jørgensen, Jørn Hjelm; Netterstrøm, Anders;

    1993-01-01

    A real-time processor (RTP) for the Danish airborne Synthetic Aperture Radar (SAR) has been designed and constructed at the Electromagnetics Institute. The implementation was completed in mid 1992, and since then the RTP has been operated successfully on several test and demonstration flights. The...... processor is capable of focusing the entire swath of the raw SAR data into full resolution, and depending on the choice made by the on-board operator, either a high resolution one-look zoom image or a spatially multilooked overview image is displayed. After a brief design review, the paper addresses various...

  17. The Intelligent Decision Support System Model of SARS

    Institute of Scientific and Technical Information of China (English)

    ZhouXingyu; ZhangJiang; LiuYang; XieYanqing; ZhangRan; ZhaoYang; HeZhongxiong

    2004-01-01

    Based on the intelligent decision support system, a new method was presented to defense the catastrophic infectious disease such as SARS, Bird Flu, etc.. By using All Set theory, the decision support system (DSS) model can be built to analyze the noise information and forecast the trend of the catastrophe then to give the method or policy to defend the disease. The model system is composed of four subsystems: the noise analysis subsystem, forecast and simulation subsystem, diagnosis subsystem and second recovery subsystem. They are discussed briefly in this paper. This model can be used not only for SARS but also for other paroxysmal accidences.

  18. The Danish polarimetric SAR for remote sensing applications

    DEFF Research Database (Denmark)

    Christensen, Erik Lintz; Madsen, Søren Nørvang; Dall, Jørgen;

    1994-01-01

    Presents the Danish polarimetric SAR system, EMISAR, and the approach taken in the system design to achieve a reliable high performance system. The design and implementation of the antenna system as well as the analog and digital hardware are discussed. The SAR utilises a dual polarised microstrip...... antenna with probe fed patches and the antenna exhibits a modified cosec-squared pattern with high polarisation discrimination. The two transmitted polarisations are time multiplexed at the transmitter and at the dual channel (V- and H-polar) receiver front end while azimuth pre-filtering is implemented...

  19. Software For Tie-Point Registration Of SAR Data

    Science.gov (United States)

    Rignot, Eric; Dubois, Pascale; Okonek, Sharon; Van Zyl, Jacob; Burnette, Fred; Borgeaud, Maurice

    1995-01-01

    SAR-REG software package registers synthetic-aperture-radar (SAR) image data to common reference frame based on manual tie-pointing. Image data can be in binary, integer, floating-point, or AIRSAR compressed format. For example, with map of soil characteristics, vegetation map, digital elevation map, or SPOT multispectral image, as long as user can generate binary image to be used by tie-pointing routine and data are available in one of the previously mentioned formats. Written in FORTRAN 77.

  20. Modulation of stable auroral red (SAR) arc occurrence rates

    International Nuclear Information System (INIS)

    Data taken by the Pacific Northwest Laboratory photometer chain have been reviewed in a comprehensive search for stable auroral red (SAR) arc events during the period 1968--1978. Results of this search indicate both a seasonal and solar cycle control of SAR arclike events. The occurrence rate of these events is shown to follow the solar activity cycle. though with a phase lag of 2--3 years. Further, a rather distinct summertime minimum of occurrence frequency is pointed out (northern hemisphere). Possible mechanisms for the existence of this effect are discussed

  1. Reconsideration of Ambiguities in Quad-Pol SAR

    OpenAIRE

    Villano, Michelangelo; Krieger, Gerhard; Moreira, Alberto

    2016-01-01

    Merging the complex signals available from both cross-polarized (cross-pol) channels of a quad-polarimetric (quad-pol) synthetic aperture radar (SAR) may lead not only to a 3-dB gain in the signal-to-noise ratio (SNR), but also to a remarkable improvement in the azimuth and range ambiguity-to-signal ratios (AASR, RASR) of cross-pol data, especially if azimuth phase coding is employed. Staggered SAR operation is also addressed, for which a novel azimuth phase code is proposed. Range ambiguitie...

  2. hPEPT1 Affinity and Translocation of Selected Gln-Sar and Glu-Sar Dipeptide Derivatives

    DEFF Research Database (Denmark)

    Eriksson, A. H.; Elm, Peter L.; Begtrup, Mikael;

    2005-01-01

    using 14C-labeled Gly-Sar. Translocation was measured as fluorescence ratios induced by the substrates using the fluorescent probe BCECF and an epifluorescence microscope setup. All compounds showed high affinity to hPEPT1, but only the amides l-Gln(N,N-dimethyl)-Sar and l-Gln(N-piperidinyl)-Sar were...... been suggested. However, these are not necessarily predictive of compounds that are actually translocated by hPEPT1. More information on affinity to and translocation via hPEPT1 of side-chain-modified dipeptides may be gained by conducting a study of selected dipeptide derivatives with variety in size...... translocated by hPEPT1. hPEPT1 is very susceptible to modifications of the N-terminal amino acid side chain of dipeptidomimetic substrates, in terms of achieving compounds with high affinity for the transporter. However, as affinity is not predictive of translocation, derivatization in this position must be...

  3. Feature-based fusion of TomoSAR point clouds from multi-view TerraSAR-X data stacks

    OpenAIRE

    Wang, Yuanyuan; Zhu, Xiao Xiang

    2013-01-01

    This article presents a technique of fusing point clouds from multiple view angles generated using synthetic aperture radar (SAR) tomography. Using TerraSAR-X high resolution spotlight data stacks, one such point has a population of about 2×107 points, with a density of around 10^6 points / km2. Such large point population leads to a high computational cost while doing the fusion in 3D space. Therefore, we introduce a feature-based unsupervised technique for point clouds fusion by detectin...

  4. Study of Tropospheric Propagation Effects in Sace-borne SAR Remote Sensing: Lates Results from TerraSAR-X

    OpenAIRE

    Danklmayer, Andreas

    2008-01-01

    TerraSAR-X, the first civil German space-borne synthetic aperture radar (SAR) satellite, has been successfully launched on 15th of June, 2007. The main purpose of Synthetic aperture radar systems is to map the Earth-surface in high resolution and synthetic aperture radars are often considered as day/night and all-weather imaging systems. Whereas the first argument is true, the second does not hold in every case depending on the operating frequencies for the applied system. Indeed, recent exa...

  5. Extracting Vertical Displacement Rates in Shanghai (China) with Multi-Platform SAR Images

    OpenAIRE

    Keren Dai; Guoxiang Liu; Zhenhong Li; Tao Li; Bing Yu; Xiaowen Wang; Andrew Singleton

    2015-01-01

    This paper presents a novel method for extracting the land vertical displacement rates (VDRs) in Shanghai (China) using the multi-platform SAR images collected between 2009 and 2010, i.e., the ascending/descending COSMO-SkyMed (CSK) X-band images and the descending TerraSAR (TSX) X-band images. Different from the conventional approach the proposed method estimates the VDRs by multi-temporal interferometric SAR processing (i.e., temporarily coherent point InSAR, TCPInSAR) and the localized lea...

  6. Automated extraction of pressure ridges from SAR images of sea ice - Comparison with surface truth

    Science.gov (United States)

    Vesecky, J. F.; Smith, M. P.; Samadani, R.; Daida, J. M.; Comiso, J. C.

    1991-01-01

    The authors estimate the characteristics of ridges and leads in sea ice from SAR (synthetic aperture radar) images. Such estimates are based on the hypothesis that bright filamentary features in SAR sea ice images correspond with pressure ridges. A data set collected in the Greenland Sea in 1987 allows this hypothesis to be evaluated for X-band SAR images. A preliminary analysis of data collected from SAR images and ice elevation (from a laser altimeter) is presented. It is found that SAR image brightness and ice elevation are clearly related. However, the correlation, using the data and techniques applied, is not strong.

  7. Reverse genetics of SARS-related coronavirus using vaccinia virus-based recombination.

    Directory of Open Access Journals (Sweden)

    Sjoerd H E van den Worm

    Full Text Available Severe acute respiratory syndrome (SARS is a zoonotic disease caused by SARS-related coronavirus (SARS-CoV that emerged in 2002 to become a global health concern. Although the original outbreak was controlled by classical public health measures, there is a real risk that another SARS-CoV could re-emerge from its natural reservoir, either in its original form or as a more virulent or pathogenic strain; in which case, the virus would be difficult to control in the absence of any effective antiviral drugs or vaccines. Using the well-studied SARS-CoV isolate HKU-39849, we developed a vaccinia virus-based SARS-CoV reverse genetic system that is both robust and biosafe. The SARS-CoV genome was cloned in separate vaccinia virus vectors, (vSARS-CoV-5prime and vSARS-CoV-3prime as two cDNAs that were subsequently ligated to create a genome-length SARS-CoV cDNA template for in vitro transcription of SARS-CoV infectious RNA transcripts. Transfection of the RNA transcripts into permissive cells led to the recovery of infectious virus (recSARS-CoV. Characterization of the plaques produced by recSARS-CoV showed that they were similar in size to the parental SARS-CoV isolate HKU-39849 but smaller than the SARS-CoV isolate Frankfurt-1. Comparative analysis of replication kinetics showed that the kinetics of recSARS-CoV replication are similar to those of SARS-CoV Frankfurt-1, although the titers of virus released into the culture supernatant are approximately 10-fold less. The reverse genetic system was finally used to generate a recSARS-CoV reporter virus expressing Renilla luciferase in order to facilitate the analysis of SARS-CoV gene expression in human dendritic cells (hDCs. In parallel, a Renilla luciferase gene was also inserted into the genome of human coronavirus 229E (HCoV-229E. Using this approach, we demonstrate that, in contrast to HCoV-229E, SARS-CoV is not able to mediate efficient heterologous gene expression in hDCs.

  8. Combination of Conventional and Advanced DInSAR to Monitor Very Fast Mining Subsidence with TerraSAR-X Data: Bytom City (Poland)

    OpenAIRE

    Maria Przyłucka; Gerardo Herrera; Marek Graniczny; Davide Colombo; Marta Béjar-Pizarro

    2015-01-01

    In this work, the analysis of TerraSAR-X satellite images combining both conventional and advanced Differential Synthetic Aperture Radar Interferometry (DInSAR) approaches has proven to be effective to detect and monitor fast evolving mining subsidence on urban areas in the Upper Silesian Coal Basin (Poland). This region accounts for almost three million inhabitants where mining subsidence has produced severe damage to urban structures and infrastructures in recent years. Conventional DInSAR ...

  9. Multistatic SAR Imaging: First Results of a Four Phase Center Experiment with TerraSAR-X and TanDEM-X

    OpenAIRE

    Kraus, Thomas; Bräutigam, Benjamin; Bachmann, Markus; Krieger, Gerhard

    2016-01-01

    Multichannel synthetic aperture radar (SAR) imaging offers the possibility to overcome the pulse repetition frequency (PRF) constraints inherent to single-channel SAR systems. The multichannel approach enables the acquisition of wide swathes with high azimuth resolution. Using a constellation or swarm of small satellites, a cost efficient, faulttolerant system can be envisaged. This paper describes the first results of a multistatic four phase center experiment conducted with TerraSAR-X an...

  10. DIRECTION AMBIGUITY RESOLUTION FROM SAR IMAGERY: A NEW APPROACH

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Ambiguity problem is inherent in synthetic aperture radar (SAR)images of ocean waves. A new method is developed based on the propagation theory of gravity waves to remove this kind of ambiguity from a single frame of real image. The results from a case study presented in this paper show good agreement to in-phase wave data.

  11. SAR imaging via iterative adaptive approach and sparse Bayesian learning

    Science.gov (United States)

    Xue, Ming; Santiago, Enrique; Sedehi, Matteo; Tan, Xing; Li, Jian

    2009-05-01

    We consider sidelobe reduction and resolution enhancement in synthetic aperture radar (SAR) imaging via an iterative adaptive approach (IAA) and a sparse Bayesian learning (SBL) method. The nonparametric weighted least squares based IAA algorithm is a robust and user parameter-free adaptive approach originally proposed for array processing. We show that it can be used to form enhanced SAR images as well. SBL has been used as a sparse signal recovery algorithm for compressed sensing. It has been shown in the literature that SBL is easy to use and can recover sparse signals more accurately than the l 1 based optimization approaches, which require delicate choice of the user parameter. We consider using a modified expectation maximization (EM) based SBL algorithm, referred to as SBL-1, which is based on a three-stage hierarchical Bayesian model. SBL-1 is not only more accurate than benchmark SBL algorithms, but also converges faster. SBL-1 is used to further enhance the resolution of the SAR images formed by IAA. Both IAA and SBL-1 are shown to be effective, requiring only a limited number of iterations, and have no need for polar-to-Cartesian interpolation of the SAR collected data. This paper characterizes the achievable performance of these two approaches by processing the complex backscatter data from both a sparse case study and a backhoe vehicle in free space with different aperture sizes.

  12. Features of clinical and radiographic appearances of SARS in children

    International Nuclear Information System (INIS)

    Objective: To evaluate the features of clinical and radiographic appearances of SARS in children. Methods: The chest films obtained at clinical presentation and during treatment in 18 children with confirmed SARS were retrospectively evaluated. Results: The main X-ray manifestations included: (1) air-space opacity in 13/18; (2) round lesion with clear margin in 3/18; (3) ground-glass lesions in 2/18; (4) unilateral and single focal involvement was more common in children than in adults (5) no reticular shadow, lymphanopathy or pleural effusion was demonstrated; (6) radiographic changes of foci was not as rapid in children as in adults. The lesions migrated in 1 case. The average absorption time of the lesions was 19 days, and most of them had no remnant. Conclusion: Compare with that in adults , the clinical manifestation was not so severe in children with SARS, and most of the infected children had clear contact history. Chest X-ray appearance in affected children mainly showed unilateral involvement of the lungs with chiefly air-space infiltrates. Remnant lesion of lung is rare in children. Differential diagnosis of SARS in children includes mycoplasma pneumonia or adenovirus pneumonia

  13. SAR Data Fusion Imaging Method Oriented to Target Feature Extraction

    Directory of Open Access Journals (Sweden)

    Yang Wei

    2015-02-01

    Full Text Available To deal with the difficulty for target outlines extracting precisely due to neglect of target scattering characteristic variation during the processing of high-resolution space-borne SAR data, a novel fusion imaging method is proposed oriented to target feature extraction. Firstly, several important aspects that affect target feature extraction and SAR image quality are analyzed, including curved orbit, stop-and-go approximation, atmospheric delay, and high-order residual phase error. Furthermore, the corresponding compensation methods are addressed as well. Based on the analysis, the mathematical model of SAR echo combined with target space-time spectrum is established for explaining the space-time-frequency change rule of target scattering characteristic. Moreover, a fusion imaging strategy and method under high-resolution and ultra-large observation angle range conditions are put forward to improve SAR quality by fusion processing in range-doppler and image domain. Finally, simulations based on typical military targets are used to verify the effectiveness of the fusion imaging method.

  14. Detecting and monitoring aquacultural patterns through multitemporal SAR imagery analysis

    Science.gov (United States)

    Profeti, Giuliana; Travaglia, Carlo; Carla, Roberto

    2003-03-01

    The inventory and monitoring of aquaculture areas are essential tools for decision-making at a governmental level in developing countries. With the use of satellite imagery, these tasks can be performed in an accurate, rapid and objective way. This approach is also economically viable, as the worth of aquaculture far outweighs its cost. This paper describes a methodology for identifying and monitoring shrimp farms by means of multi-temporal satellite SAR data. SAR offer all-weather capabilities, an important characteristic since shrimp farms exist in tropical and sub-tropical areas. Moreover, the backscatter effect created by the dykes surrounding the ponds produces a typical pattern which allows the interpreter to distinguish them from other types of water-covered surfaces. However, the presence of speckle noise limits the interpretability of SAR imagery. To increase it, a multi-temporal set of four scenes covering the study area was processed by using a method that enhances time-invariant spatial features and reduces speckle without compromising the geometrical resolution of the images. The enhanced SAR imagery has proved to be valuable in identifying shrimp farm patterns with a field-tested accuracy of more than 90 percent. The methodology reported in this study has been tested with the ground truth obtained under operative conditions in Sri Lanka, thanks to the support of the FAO TCP/SRL/6712 project.

  15. Suicidality Among High School Students in Hong Kong, SAR

    Science.gov (United States)

    Yip, Paul S. F.; Liu, K. Y.; Lam, T. H.; Stewart, Sunita M.; Chen, Eric; Fan, Susan

    2004-01-01

    Suicide is the leading cause of death in Hong Kong SAR for the youth aged 15?24. This study examined the prevalence of suicidality among secondary school students in Hong Kong using a representative, territory-wide sample of 2,586 students. Suicidal behaviors can be conceptualized as a spectrum of self-destructive behaviors. Cumulative logit model…

  16. The impact of curved satellite tracks on SAR focusing

    DEFF Research Database (Denmark)

    Mohr, Johan Jacob; Madsen, Søren Nørvang

    2000-01-01

    This paper addresses the geometric effect of processing single look complex synthetic aperture radar (SAR) data to a reference squint angle different from that given by the center of the real antenna beam. For data acquired on a straight flight line, the required transformation of radar coordinat...

  17. Compact time- and space-integrating SAR processor: performance analysis

    Science.gov (United States)

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

    1995-06-01

    Progress made during the previous 12 months toward the fabrication and test of a flight demonstration prototype of the acousto-optic time- and space-integrating real-time SAR image formation processor is reported. Compact, rugged, and low-power analog optical signal processing techniques are used for the most computationally taxing portions of the SAR imaging problem to overcome the size and power consumption limitations of electronic approaches. 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 for this year include tests of a laboratory version of the RAPID SAR concept on phase history data generated from real SAR high-resolution imagery; a description of the new compact 2D acousto-optic scanner that has a 2D space bandwidth product approaching 106 sports, specified and procured for NEOS Technologies during the last year; and a design and layout of the optical module portion of the flight-worthy prototype.

  18. A new C-band SAR for ERS-1 underflights

    DEFF Research Database (Denmark)

    Madsen, Søren Nørvang; Skou, Niels; Christensen, Erik Lintz

    A high-resolution airborne C-band synthetic aperture radar (SAR) has been designed, built, and tested. The radar design based on digital technology to the largest possible extent, to make the system as adaptable as possible. This has resulted in a very flexible radar with variable resolution, swa...

  19. A BRIEF DISCUSSION REGARDING PRION DISEASES AND SARS

    Science.gov (United States)

    Recent diagnoses of Mad Cow disease in Canadian and American cattle has increased concern for this disease and other TSEs in North America. This presentation provides a quick review of the important features of Mad Cow disease as well as SARS as they might relate to land applicat...

  20. Wind mapping offshore in coastal Mediterranean area using SAR images

    DEFF Research Database (Denmark)

    Calaudi, Rosamaria; Arena, Felice; Badger, Merete; Sempreviva, Anna Maria

    Satellite observations of the ocean surface from Synthetic Aperture Radars (SAR) provide information about the spatial wind variability over large areas. This is of special interest in the Mediterranean, where spatial wind information is only provided by sparse buoys, often with long periods of...

  1. Offshore Wind Resource Estimation in Mediterranean Area Using SAR Images

    DEFF Research Database (Denmark)

    Calaudi, Rosamaria; Arena, Felice; Badger, Merete; Sempreviva, Anna Maria

    Satellite observations of the ocean surface from Synthetic Aperture Radars (SAR) provide information about the spatial wind variability over large areas. This is of special interest in the Mediterranean, where spatial wind information is only provided by sparse buoys, often with long periods of...

  2. InSAR observations of active volcanoes in Latin America

    Science.gov (United States)

    Morales Rivera, A. M.; Chaussard, E.; Amelung, F.

    2012-12-01

    Over the last decade satellite-based interferometric synthetic aperture radar (InSAR) has developed into a well-known technique to gauge the status of active volcanoes. The InSAR technique can detect the ascent of magma to shallow levels of the volcanic plumbing system because new arriving magma pressurizes the system. This is likely associated with the inflation of the volcanic edifice and the surroundings. Although the potential of InSAR to detect magma migration is well known, the principal limitation was that only for few volcanoes frequent observations were acquired. The ALOS-1 satellite of the Japanese Aerospace Exploration Agency (JAXA) acquired a global L-band data set of 15-20 acquisitions during 2006-2011. Here we use ALOS InSAR and Small Baseline (SB) time-series methods for a ground deformation survey of Latin America with emphasis on the northern Andes. We present time-dependent ground deformation data for the volcanoes in Colombia, Ecuador and Peru and interpret the observations in terms of the dynamics of the volcanic systems.

  3. EMISAR: A Dual-frequency, Polarimetric Airborne SAR

    DEFF Research Database (Denmark)

    Dall, Jørgen; Christensen, Erik Lintz

    2002-01-01

    EMISAR is a fully polarimetric, dual frequency (L- and C-band) SAR system designed for remote sensing applications. The data are usually processed to 2×2 m resolution. The system has the capability of C-band cross-track single-pass interferometry and fully polarimetric repeat-pass interferometry...

  4. Range non-linearities correction in FMCW SAR

    NARCIS (Netherlands)

    Meta, A.; Hoogeboom, P.; Ligthart, L.P.

    2006-01-01

    The limiting factor to the use of Frequency Modulated Continuous Wave (FMCW) technology with Synthetic Aperture Radar (SAR) techniques to produce lightweight, cost effective, low power consuming imaging sensors with high resolution, is the well known presence of non-linearities in the transmitted si

  5. Remote sensing measurements of thermokarst subsidence using InSAR

    Science.gov (United States)

    Liu, L.; Schaefer, K. M.; Chen, A. C.; Gusmeroli, A.; Zebker, H. A.; Zhang, T.

    2015-09-01

    Thawing of ice-rich permafrost followed by surface subsidence results in irregular, depressed landforms known as thermokarst. Many remote sensing studies have identified thermokarst landforms and mapped their changes. However, the intrinsic dynamic thermokarst process of surface subsidence remains a challenge to quantify and is seldom examined using remote sensing methods. In this study we used spaceborne interferometric synthetic aperture radar (InSAR) data to map surface subsidence trends at a thermokarst landform located near Deadhorse on the North Slope of Alaska. A pipeline access road constructed in the 1970s triggered the thawing of the permafrost, causing subsequent expansion of the thermokarst landform. Using Phased Array type L band Synthetic Aperture Radar images acquired by the Advanced Land Observing Satellite-1, our InSAR analysis reveals localized thermokarst subsidence of 2-8 cm/yr between 2006 and 2010, equivalent to an ice volume loss of about 1.2 × 107 m3/yr. Comparisons between InSAR subsidence trends and lidar microtopography suggest a characteristic time of 8 years of thermokarst development. We also quantitatively explain the difficulty, uncertainties, and possible biases in separating thermokarst-induced, irreversible subsidence from cyclic seasonal deformation. Our study illustrates that InSAR is an effective tool for mapping and studying active thermokarst processes and quantifying ice loss.

  6. SAR antenna design for ambiguity and multipath suppression

    DEFF Research Database (Denmark)

    Christensen, Erik Lintz; Dich, Mikael

    1993-01-01

    are obtained from the required swath and the azimuth footprint needed for the SAR processing. The radiation from a real antenna causes unwanted signal returns that lead to intensity variations (multipath) and ghost echoes (ambiguity). Additional specifications are deduced by considering these signals...

  7. SAR: A novel application for FM-CW radars

    NARCIS (Netherlands)

    Wit, J.J.M. de; Hoogeboom, P.

    2001-01-01

    For small-scale earth observation applications, there ia a special interest in low-cost, high-resolution imaging radars small, enough to be operated from small, possibly unmanned aircraft. The combination of FM-CW technology and the high resolution of SAR systems should result in such a small, cost-

  8. Statistical and separability properties of the polarimetry SAR matrix elements

    Science.gov (United States)

    Bahrami, Ala; Sahebi, Mahmoud R.; Valadan Zouj, Mohammad J.; Ahmadi, Salman; Dehghani, Maryam; Nandipati, Anand

    2009-09-01

    The development of the polarimetric synthetic aperture radar (PolSAR) applications has been accelerated by coming of new generation of SAR polarimetric satellites (TerraSAR-X, COSMO-SkyMed, RADARSAT-2, ALOS, etc.). The aim of this article is to extract the information content of the polarimetric SAR data. Cross products of four channels "HH, HV, VH, and VV" could be at least nine features in vector space and by applying the different class separability criterion, the impacts of each feature, for extracting different patterns, could be tested. We have chosen the large distance between classes and small distance within-class variances as our criterion to rank the features. Due to high mutual correlation between some of the features, it is preferable to combine the features which result in the lower number of features. Also the computational complexity will be decreased when we have lower number of features. Due to these advantages, our goal would be to decrease the number of features in vector space. To achieve that, a subset of ranked features consists of two to nine ranked features will be classified and the classification accuracy of different subsets will be evaluated. It is possible that some of the new features that have been added to the old subsets change the classification accuracy. Finally different feature subsets which were selected based on the various class-separability approaches will be compared. The subset that gives the highest overall accuracy would be the best representative of the nine originally features.

  9. The Performance Analysis Based on SAR Sample Covariance Matrix

    Directory of Open Access Journals (Sweden)

    Esra Erten

    2012-03-01

    Full Text Available Multi-channel systems appear in several fields of application in science. In the Synthetic Aperture Radar (SAR context, multi-channel systems may refer to different domains, as multi-polarization, multi-interferometric or multi-temporal data, or even a combination of them. Due to the inherent speckle phenomenon present in SAR images, the statistical description of the data is almost mandatory for its utilization. The complex images acquired over natural media present in general zero-mean circular Gaussian characteristics. In this case, second order statistics as the multi-channel covariance matrix fully describe the data. For practical situations however, the covariance matrix has to be estimated using a limited number of samples, and this sample covariance matrix follow the complex Wishart distribution. In this context, the eigendecomposition of the multi-channel covariance matrix has been shown in different areas of high relevance regarding the physical properties of the imaged scene. Specifically, the maximum eigenvalue of the covariance matrix has been frequently used in different applications as target or change detection, estimation of the dominant scattering mechanism in polarimetric data, moving target indication, etc. In this paper, the statistical behavior of the maximum eigenvalue derived from the eigendecomposition of the sample multi-channel covariance matrix in terms of multi-channel SAR images is simplified for SAR community. Validation is performed against simulated data and examples of estimation and detection problems using the analytical expressions are as well given.

  10. Multiple Baseline SAR Tomography's Performance Analysis in Forest 3-D Structure Mapping with long term ALOS L band repeat pass InSAR data

    Science.gov (United States)

    Lin, Q.; Zebker, H. A.

    2013-12-01

    Acquiring accurate measurement of three-dimensional structure of forest globally , is key to improve quantitative understanding of the state and dynamics of ecosystems, particularly global carbon cycle. Moreover, forest contains a large portion of Earth's renewable natural resources. All these require an accurate, timely and cost-effective global forest vertical structure mapping. Synthetic Aperture Radar Interferometry (InSAR) remote sensing is widely acknowledged as a powerful tool to accomplish this task. Within the last decade, a number of experimental demonstrations of 3-D InSAR techniques have suggested the possibility of remotely sensing global 3-D vegetation structure. Among all the 3-D InSAR techniques, Multiple Baseline SAR Tomography( MB Tomo-SAR) is a very promising one. Multiple baseline SAR tomography exploits InSAR images acquired from different baselines and form a synthetic aperture in the vertical direction in order to retrieval vertical structure. Though theoretical predictions and several laboratory experiments show great reconstruction results, applying the method in real world condition still face a lot of challenges, including low acquisition number, irregular sample distribution, atmospheric phase noise and time decorrelation effect. In this article, we use L band ALOS spaceborne SAR data in Hawaii area to test the performance of MB TomoSAR . In the process, advanced Fourier beamforming method, atmospheric phase screen removal algorithm and time decorrelation effect are all applied. In addition, we also utilize the Landsat vegetation index and the result with other 3-D reconstruction methods as comparison to validate its performance.

  11. GMTI for Squint Looking XTI-SAR with Rotatable Forward-Looking Array.

    Science.gov (United States)

    Jing, Kai; Xu, Jia; Huang, Zuzhen; Yao, Di; Long, Teng

    2016-01-01

    To realize ground moving target indication (GMTI) for a forward-looking array, we propose a novel synthetic aperture radar (SAR) system, called rotatable cross-track interferometry SAR (Ro-XTI-SAR), for squint-looking application in this paper. By changing the angle of the cross-track baseline, the interferometry phase component of squint-looking Ro-XTI-SAR caused by the terrain height can be approximately adjusted to zero, and then the interferometry phase of Ro-XTI-SAR is only sensitive to targets' motion and can be equivalent to the along track interferometry SAR (ATI-SAR). Furthermore, the conventional displaced phase center array (DPCA) method and constant false alarm (CFAR) processing can be used to accomplish the successive clutter suppression, moving targets detection and relocation. Furthermore, the clutter suppressing performance is discussed with respect to different system parameters. Finally, some results of numerical experiments are provided to demonstrate the effectiveness of the proposed system. PMID:27314350

  12. Space Radar Image of West Texas - SAR scan

    Science.gov (United States)

    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

  13. Internal Wave Study in the South China Sea Using SAR

    Science.gov (United States)

    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.

  14. Utilizing SAR and Multispectral Integrated Data for Emergency Response

    Science.gov (United States)

    Havivi, S.; Schvartzman, I.; Maman, S.; Marinoni, A.; Gamba, P.; Rotman, S. R.; Blumberg, D. G.

    2016-06-01

    Satellite images are used widely in the risk cycle to understand the exposure, refine hazard maps and quickly provide an assessment after a natural or man-made disaster. Though there are different types of satellite images (e.g. optical, radar) these have not been combined for risk assessments. The characteristics of different remote sensing data type may be extremely valuable for monitoring and evaluating the impacts of disaster events, to extract additional information thus making it available for emergency situations. To base this approach, two different change detection methods, for two different sensor's data were used: Coherence Change Detection (CCD) for SAR data and Covariance Equalization (CE) for multispectral imagery. The CCD provides an identification of the stability of an area, and shows where changes have occurred. CCD shows subtle changes with an accuracy of several millimetres to centimetres. The CE method overcomes the atmospheric effects differences between two multispectral images, taken at different times. Therefore, areas that had undergone a major change can be detected. To achieve our goals, we focused on the urban areas affected by the tsunami event in Sendai, Japan that occurred on March 11, 2011 which affected the surrounding area, coastline and inland. High resolution TerraSAR-X (TSX) and Landsat 7 images, covering the research area, were acquired for the period before and after the event. All pre-processed and processed according to each sensor. Both results, of the optical and SAR algorithms, were combined by resampling the spatial resolution of the Multispectral data to the SAR resolution. This was applied by spatial linear interpolation. A score representing the damage level in both products was assigned. The results of both algorithms, high level of damage is shown in the areas closer to the sea and shoreline. Our approach, combining SAR and multispectral images, leads to more reliable information and provides a complete scene for

  15. Evaluation of the operational SAR based Baltic sea ice concentration products

    Science.gov (United States)

    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.

  16. Forest parameter estimation using polarimetric SAR interferometry techniques at low frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung-Kuk

    2013-05-01

    Polarimetric Synthetic Aperture Radar Interferometry (Pol-InSAR) is an active radar remote sensing technique based on the coherent combination of both polarimetric and interferometric observables. The Pol-InSAR technique provided a step forward in quantitative forest parameter estimation. In the last decade, airborne SAR experiments evaluated the potential of Pol-InSAR techniques to estimate forest parameters (e.g., the forest height and biomass) with high accuracy over various local forest test sites. This dissertation addresses the actual status, potentials and limitations of Pol-InSAR inversion techniques for 3-D forest parameter estimations on a global scale using lower frequencies such as L- and P-band. The multi-baseline Pol-InSAR inversion technique is applied to optimize the performance with respect to the actual level of the vertical wave number and to mitigate the impact of temporal decorrelation on the Pol-InSAR forest parameter inversion. Temporal decorrelation is a critical issue for successful Pol-InSAR inversion in the case of repeat-pass Pol-InSAR data, as provided by conventional satellites or airborne SAR systems. Despite the limiting impact of temporal decorrelation in Pol-InSAR inversion, it remains a poorly understood factor in forest height inversion. Therefore, the main goal of this dissertation is to provide a quantitative estimation of the temporal decorrelation effects by using multi-baseline Pol-InSAR data. A new approach to quantify the different temporal decorrelation components is proposed and discussed. Temporal decorrelation coefficients are estimated for temporal baselines ranging from 10 minutes to 54 days and are converted to height inversion errors. In addition, the potential of Pol-InSAR forest parameter estimation techniques is addressed and projected onto future spaceborne system configurations and mission scenarios (Tandem-L and BIOMASS satellite missions at L- and P-band). The impact of the system parameters (e.g., bandwidth

  17. Precision and accuracy of two luminescence dating techniques for retrospective dosimetry: SAR-OSL and SAR-ITL

    Energy Technology Data Exchange (ETDEWEB)

    Pagonis, Vasilis, E-mail: vpagonis@mcdaniel.ed [Physics Department, McDaniel College, Westminster, MD 21157 (United States); Baker, Atlee; Larsen, Meredith; Thompson, Zachary [Physics Department, McDaniel College, Westminster, MD 21157 (United States)

    2011-04-01

    Luminescence techniques based on thermally or optically stimulated signals are used extensively for estimating the equivalent dose (ED) of quartz samples for dating and retrospective dosimetry. This paper presents simulations of two luminescence dating protocols which use single aliquots of the quartz samples. The first protocol is the well-known single-aliquot regenerative optically stimulated luminescence (SAR-OSL) protocol for quartz. The second protocol was developed more recently and is based on a thermoluminescence (TL) signal measured under isothermal conditions (termed the SAR-ITL technique). The simulations are carried out using a recently published comprehensive kinetic model for quartz, consisting of 11 electron and hole traps and centers. The complete sequence of the two experimental protocols is simulated using the same set of kinetic parameters. The simulated dose response curves for the two protocols are found to be very similar to published experimental data. The relative intrinsic accuracy and precision of the two techniques is estimated by simulating one hundred random variants of the natural samples, and by calculating the equivalent doses using each technique. The 100 simulated natural variants are generated by keeping the transition probabilities between energy levels fixed, while allowing simultaneous random variations of the concentrations of the 11 energy levels. The SAR-OSL protocol was found to be intrinsically both more accurate and more precise than the SAR-ITL protocol. We investigate several experimental factors which affect the precision and accuracy of the two protocols. New simulations are presented for commonly used sensitivity tests consisting of successive cycles of sample irradiation with the same dose, followed by measurements of the sensitivity corrected L/T signals. These new simulations provide valuable insight into the previously reported sensitivity changes taking place during application of the SAR-ITL protocol.

  18. Precision and accuracy of two luminescence dating techniques for retrospective dosimetry: SAR-OSL and SAR-ITL

    Science.gov (United States)

    Pagonis, Vasilis; Baker, Atlee; Larsen, Meredith; Thompson, Zachary

    2011-04-01

    Luminescence techniques based on thermally or optically stimulated signals are used extensively for estimating the equivalent dose (ED) of quartz samples for dating and retrospective dosimetry. This paper presents simulations of two luminescence dating protocols which use single aliquots of the quartz samples. The first protocol is the well-known single-aliquot regenerative optically stimulated luminescence (SAR-OSL) protocol for quartz. The second protocol was developed more recently and is based on a thermoluminescence (TL) signal measured under isothermal conditions (termed the SAR-ITL technique). The simulations are carried out using a recently published comprehensive kinetic model for quartz, consisting of 11 electron and hole traps and centers. The complete sequence of the two experimental protocols is simulated using the same set of kinetic parameters. The simulated dose response curves for the two protocols are found to be very similar to published experimental data. The relative intrinsic accuracy and precision of the two techniques is estimated by simulating one hundred random variants of the natural samples, and by calculating the equivalent doses using each technique. The 100 simulated natural variants are generated by keeping the transition probabilities between energy levels fixed, while allowing simultaneous random variations of the concentrations of the 11 energy levels. The SAR-OSL protocol was found to be intrinsically both more accurate and more precise than the SAR-ITL protocol. We investigate several experimental factors which affect the precision and accuracy of the two protocols. New simulations are presented for commonly used sensitivity tests consisting of successive cycles of sample irradiation with the same dose, followed by measurements of the sensitivity corrected L/ T signals. These new simulations provide valuable insight into the previously reported sensitivity changes taking place during application of the SAR-ITL protocol.

  19. Severe acute respiratory syndrome (SARS): chest radiographic features in children

    International Nuclear Information System (INIS)

    We abstracted data (n=62) on the radiologic appearance and course of SARS in pediatric patients with suspect (n=25) or probable (n=37) SARS, diagnosed in five hospital sites located in three cities: Toronto, Singapore, and Hong Kong. Available chest radiographs and thoracic CTs were reviewed for the presence of the following radiographic findings: airspace disease, air bronchograms, airways inflammation and peribronchial thickening, interstitial disease, pleural effusion, and hilar adenopathy. A total of 62 patients (suspect=25, probable=37) were evaluated for SARS. Patient ages ranged from 5.5 months to 17 years and 11.5 months (average, 6 years and 10 months) with a female-to-male ratio of 32:30. Forty-one patients (66.1%) were in close contact with other probable, suspect, or quarantined cases; 10 patients (16.1%) had recently traveled to WHO-designated affected areas within 10 days; and 7 patients (11.2%) were transferred from other hospitals that had SARS patients. Three patients, who did not have close/hospital contact or travel history to affected areas, were classified as SARS cases based on their clinical signs and symptoms and on the fact that they were living in an endemic area. The most prominent clinical presentations were fever, with a temperature over 38 C (100%), cough (62.9%), rhinorrhea (22.6%), myalgia (17.7%), chills (14.5%), and headache (11.3%). Other findings included sore throat (9.7%), gastrointestinal symptoms (9.7%), rigor (8.1%), and lethargy (6.5%). In general, fever and cough were the most common clinical presentations amongst younger pediatric SARS cases (age<10 years), whereas, in addition to these symptoms, headache, myalgia, sore throat, chills, and/or rigor were common in older patients (age≥10 years). The chest radiographs of 35.5% of patients were normal. The most prominent radiological findings that were observed in the remaining patients were areas of consolidation (45.2%), often peripheral with multifocal lesions in 22

  20. InSAR Scientific Computing Environment on the Cloud

    Science.gov (United States)

    Rosen, P. A.; Shams, K. S.; Gurrola, E. M.; George, B. A.; Knight, D. S.

    2012-12-01

    In response to the needs of the international scientific and operational Earth observation communities, spaceborne Synthetic Aperture Radar (SAR) systems are being tasked to produce enormous volumes of raw data daily, with availability to scientists to increase substantially as more satellites come online and data becomes more accessible through more open data policies. The availability of these unprecedentedly dense and rich datasets has led to the development of sophisticated algorithms that can take advantage of them. In particular, interferometric time series analysis of SAR data provides insights into the changing earth and requires substantial computational power to process data across large regions and over large time periods. This poses challenges for existing infrastructure, software, and techniques required to process, store, and deliver the results to the global community of scientists. The current state-of-the-art solutions employ traditional data storage and processing applications that require download of data to the local repositories before processing. This approach is becoming untenable in light of the enormous volume of data that must be processed in an iterative and collaborative manner. We have analyzed and tested new cloud computing and virtualization approaches to address these challenges within the context of InSAR in the earth science community. Cloud computing is democratizing computational and storage capabilities for science users across the world. The NASA Jet Propulsion Laboratory has been an early adopter of this technology, successfully integrating cloud computing in a variety of production applications ranging from mission operations to downlink data processing. We have ported a new InSAR processing suite called ISCE (InSAR Scientific Computing Environment) to a scalable distributed system running in the Amazon GovCloud to demonstrate the efficacy of cloud computing for this application. We have integrated ISCE with Polyphony to

  1. Severe acute respiratory syndrome (SARS): chest radiographic features in children

    Energy Technology Data Exchange (ETDEWEB)

    Babyn, Paul S.; Gahunia, Harpal K.; Manson, David [Department of Diagnostic Imaging, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario (Canada); Chu, Winnie C.W.; Metreweli, Constantine [Prince of Wales Hospital, Shatin (China); Department of Diagnostic Radiology and Organ Imaging, Chinese University of Hong Kong (China); Tsou, Ian Y.Y.; Wansaicheong, Gervais K.L.; Chee, Thomas S.G.; Kaw, Gregory J.L. [Department of Diagnostic Radiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng (Singapore); Allen, Upton; Bitnun, Ari; Read, Stanley [Division of Infectious Diseases, Hospital for Sick Children, 555 University Avenue, Toronto, Ontario (Canada); Cheng, Frankie W.T.; Fok, Tai-Fai; Hon, Ellis K.L.; Li, Albert M.; Ng, Pak-Cheung [Department of Paediatrics, Chinese University of Hong Kong, Prince of Wales Hospital, 30-32 Ngan Shing Street, Shatin, Hong Kong, SAR (China); Chiu, Man-Chun; Leung, Chi-Wai [Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Lai King Hill Road, Lai Chi Kok, Hong Kong, SAR (China); Khong, Pek L. [Department of Diagnostic Radiology, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Hong Kong, SAR (China); Stringer, David A.

    2004-01-01

    We abstracted data (n=62) on the radiologic appearance and course of SARS in pediatric patients with suspect (n=25) or probable (n=37) SARS, diagnosed in five hospital sites located in three cities: Toronto, Singapore, and Hong Kong. Available chest radiographs and thoracic CTs were reviewed for the presence of the following radiographic findings: airspace disease, air bronchograms, airways inflammation and peribronchial thickening, interstitial disease, pleural effusion, and hilar adenopathy. A total of 62 patients (suspect=25, probable=37) were evaluated for SARS. Patient ages ranged from 5.5 months to 17 years and 11.5 months (average, 6 years and 10 months) with a female-to-male ratio of 32:30. Forty-one patients (66.1%) were in close contact with other probable, suspect, or quarantined cases; 10 patients (16.1%) had recently traveled to WHO-designated affected areas within 10 days; and 7 patients (11.2%) were transferred from other hospitals that had SARS patients. Three patients, who did not have close/hospital contact or travel history to affected areas, were classified as SARS cases based on their clinical signs and symptoms and on the fact that they were living in an endemic area. The most prominent clinical presentations were fever, with a temperature over 38 C (100%), cough (62.9%), rhinorrhea (22.6%), myalgia (17.7%), chills (14.5%), and headache (11.3%). Other findings included sore throat (9.7%), gastrointestinal symptoms (9.7%), rigor (8.1%), and lethargy (6.5%). In general, fever and cough were the most common clinical presentations amongst younger pediatric SARS cases (age<10 years), whereas, in addition to these symptoms, headache, myalgia, sore throat, chills, and/or rigor were common in older patients (age{>=}10 years). The chest radiographs of 35.5% of patients were normal. The most prominent radiological findings that were observed in the remaining patients were areas of consolidation (45.2%), often peripheral with multifocal lesions in 22

  2. An RF dosimeter for independent SAR measurement in MRI scanners

    International Nuclear Information System (INIS)

    Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independent SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B1) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average

  3. Evaluation of the operational SAR based Baltic Sea ice concentration products

    Science.gov (United States)

    Karvonen, Juha

    2015-07-01

    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 (Synthetic Aperture Radar) 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 for both the polarization channels, and SAR mosaicking. After preprocessing a segmentation is performed for the SAR mosaics, and some features are computed for each SAR segment. Finally the SAR concentration is estimated based on these segment-wise features. The algorithm is basically 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 grid cell (pixel) 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 Finnish Meteorological Institute (FMI) ice charts and ice concentration estimates from a radiometer algorithm.

  4. Air pollution and case fatality of SARS in the People's Republic of China: an ecologic study

    Directory of Open Access Journals (Sweden)

    Yu Shun-Zhang

    2003-11-01

    Full Text Available Abstract Background Severe acute respiratory syndrome (SARS has claimed 349 lives with 5,327 probable cases reported in mainland China since November 2002. SARS case fatality has varied across geographical areas, which might be partially explained by air pollution level. Methods Publicly accessible data on SARS morbidity and mortality were utilized in the data analysis. Air pollution was evaluated by air pollution index (API derived from the concentrations of particulate matter, sulfur dioxide, nitrogen dioxide, carbon monoxide and ground-level ozone. Ecologic analysis was conducted to explore the association and correlation between air pollution and SARS case fatality via model fitting. Partially ecologic studies were performed to assess the effects of long-term and short-term exposures on the risk of dying from SARS. Results Ecologic analysis conducted among 5 regions with 100 or more SARS cases showed that case fatality rate increased with the increment of API (case fatality = - 0.063 + 0.001 * API. Partially ecologic study based on short-term exposure demonstrated that SARS patients from regions with moderate APIs had an 84% increased risk of dying from SARS compared to those from regions with low APIs (RR = 1.84, 95% CI: 1.41–2.40. Similarly, SARS patients from regions with high APIs were twice as likely to die from SARS compared to those from regions with low APIs. (RR = 2.18, 95% CI: 1.31–3.65. Partially ecologic analysis based on long-term exposure to ambient air pollution showed the similar association. Conclusion Our studies demonstrated a positive association between air pollution and SARS case fatality in Chinese population by utilizing publicly accessible data on SARS statistics and air pollution indices. Although ecologic fallacy and uncontrolled confounding effect might have biased the results, the possibility of a detrimental effect of air pollution on the prognosis of SARS patients deserves further investigation.

  5. Depression of biofilm formation and antibiotic resistance by sarA disruption in Staphylococcus epidermidis

    Institute of Scientific and Technical Information of China (English)

    Ju-Hong Tao; Chang-Sheng Fan; Shan-E Gao; Hai-Jiao Wang; Guo-Xin Liang; Qing Zhang

    2006-01-01

    AIM: To study the effects of disruption of sarA gene on biofilm formation and antibiotic resistance of Staphylococcus epidermidis (S. epidermidis ).METHODS: In order to disrupt sarA gene, the doublecrossover homologous recombination was applied in S. epidermidis RP62A, and tetracycline resistance gene (tet) was used as the selective marker which was amplified by PCR from the pBR322 and inserted into the locus between sarA upstream and downstream,resulting in pBT2△sarA. By electroporation, the plasmid pBT2△sarA was transformed into S. epidermidis.Gene transcription was detected by real-time reverse transcription-PCR (RT-PCR). Determination of biofilm was performed in 96-well flat-bottomed culture plates, and antibiotic resistance was analyzed with test tube culture by spectrophotometry at 570 nm respectively.RESULTS: A sarA disrupted strain named S. epidermidis RP62A△sarA was constructed, which was completely defective in biofilm formation, while the sarA complement strain RP62A△sarA (pHPS9sarA) restored the biofilm formation phenotype. Additionally, the knockout of sarA resulted in decreased erythromycin and kanamycin resistance of S. epidermidis RP62A. Compared to the original strain, S. epidermidis RP62A△sarA had an increase of the sensitivity to erythromycin at 200-400 μg/mL and kanamycin at 200-800 μg/mL respectively.CONCLUSION: The knockout of sarA can result in the defect in biofilm formation and the decreased erythromycin and kanamycin resistance in S. epidermidis RP62A.

  6. Monitoring of Three Case Studies of Creeping Landslides in Ecuador using L-band SAR Interferometry (InSAR)

    Science.gov (United States)

    Mayorga Torres, T. M.; Mohseni Aref, M.

    2015-12-01

    Tannia Mayorga Torres1,21 Universidad Central del Ecuador. Faculty of Geology, Mining, Oil, and Environment 2 Hubert H. Humphrey Fellowship 2015-16 IntroductionLandslides lead to human and economic losses across the country, mainly in the winter season. On the other hand, satellite radar data has cost-effective benefits due to open-source software and free availability of data. With the purpose of establishing an early warning system of landslide-related surface deformation, three case studies were designed in the Coast, Sierra (Andean), and Oriente (jungle) regions. The objective of this work was to assess the capability of L-band InSAR to get phase information. For the calculation of the interferograms in Repeat Orbit Interferometry PACkage, the displacement was detected as the error and was corrected. The coherence images (Figure 1) determined that L-band is suitable for InSAR processing. Under this frame, as a first approach, the stacking DInSAR technique [1] was applied in the case studies [2]; however, due to lush vegetation and steep topography, it is necessary to apply advanced InSAR techniques [3]. The purpose of the research is to determine a pattern of data acquisition and successful results to understand the spatial and temporal ground movements associated with landslides. The further work consists of establishing landslide inventories to combine phases of SAR images to generate maps of surface deformation in Tumba-San Francisco and Guarumales to compare the results with ground-based measurements to determine the maps' accuracy. References[1] Sandwell D., Price E. (1998). Phase gradient approach to stacking interferograms. Journal of Geophysical Research, Vol. 103, N. B12, pp. 30,183-30,204. [2] Mayorga T., Platzeck G. (2014). Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador. NH3.5-Blue Poster B298, Vol. 16, EGU2014-16203. Austria. [3] Wasowski J., Bovenga F. (2014). Investigating landslides and unstable slopes with

  7. Initial assessment of an airborne Ku-band polarimetric SAR.

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie; Doerry, Armin Walter

    2013-02-01

    Polarimetric synthetic aperture radar (SAR) has been used for a variety of dual-use research applications since the 1940's. By measuring the direction of the electric field vector from radar echoes, polarimetry may enhance an analyst's understanding of scattering effects for both earth monitoring and tactical surveillance missions. Polarimetry may provide insight into surface types, materials, or orientations for natural and man-made targets. Polarimetric measurements may also be used to enhance the contrast between scattering surfaces such as man-made objects and their surroundings. This report represents an initial assessment of the utility of, and applications for, polarimetric SAR at Ku-band for airborne or unmanned aerial systems.

  8. Estimating tropical-forest density profiles from multibaseline interferometric SAR

    Science.gov (United States)

    Treuhaft, Robert; Chapman, Bruce; dos Santos, Joao Roberto; Dutra, Luciano; Goncalves, Fabio; da Costa Freitas, Corina; Mura, Jose Claudio; de Alencastro Graca, Paulo Mauricio

    2006-01-01

    Vertical profiles of forest density are potentially robust indicators of forest biomass, fire susceptibility and ecosystem function. Tropical forests, which are among the most dense and complicated targets for remote sensing, contain about 45% of the world's biomass. Remote sensing of tropical forest structure is therefore an important component to global biomass and carbon monitoring. This paper shows preliminary results of a multibasline interfereomtric SAR (InSAR) experiment over primary, secondary, and selectively logged forests at La Selva Biological Station in Costa Rica. The profile shown results from inverse Fourier transforming 8 of the 18 baselines acquired. A profile is shown compared to lidar and field measurements. Results are highly preliminary and for qualitative assessment only. Parameter estimation will eventually replace Fourier inversion as the means to producing profiles.

  9. Seasat SAR identification of dry climate urban land cover

    Science.gov (United States)

    Henderson, F. M.; Wharton, S. W.

    1980-01-01

    Digitally processed Seasat synthetic aperture radar (SAR) imagery of the Denver, Colorado area was examined to assess its potential for mapping urban land cover and the compatibility of SAR derived classes with those described in the U.S. Geological Survey classification system. The entire scene was interpreted to generate a small-scale land cover map. In addition, six subscene enlargements representative of urban land cover categories extant in the area were used as test sites for detailed analysis of land cover types. Two distinct approaches were employed and compared in examining the imagery - a visual interpretation of black-and-white positive transparencies and an automated-machine/visual interpretation. The latter used the Image 100 interactive image analysis system to generate land cover classes by density level slicing of the image frequency histogram.

  10. Classification of Polarimetric SAR Data Using Dictionary Learning

    DEFF Research Database (Denmark)

    Vestergaard, Jacob Schack; Nielsen, Allan Aasbjerg; Dahl, Anders Lindbjerg;

    2012-01-01

    This contribution deals with classification of multilook fully polarimetric synthetic aperture radar (SAR) data by learning a dictionary of crop types present in the Foulum test site. The Foulum test site contains a large number of agricultural fields, as well as lakes, forests, natural vegetation......, grasslands and urban areas, which make it ideally suited for evaluation of classification algorithms. Dictionary learning centers around building a collection of image patches typical for the classification problem at hand. This requires initial manual labeling of the classes present in the data and is thus...... covariance matrix as the dictionary element features. Furthermore, we compare the method of dictionary learning, in the context of classifying polarimetric SAR data, with standard classification methods based on single-pixel measurements....

  11. Image Combination Analysis in SPECAN Algorithm of Spaceborne SAR

    Institute of Scientific and Technical Information of China (English)

    臧铁飞; 李方慧; 龙腾

    2003-01-01

    An analysis of image combination in SPECAN algorithm is delivered in time-frequency domain in detail and a new image combination method is proposed. For four multi-looks processing one sub-aperture data in every three sub-apertures is processed in this combination method. The continual sub-aperture processing in SPECAN algorithm is realized and the processing efficiency can be dramatically increased. A new parameter is also put forward to measure the processing efficient of SAR image processing. Finally, the raw data of RADARSAT are used to test the method and the result proves that this method is feasible to be used in SPECAN algorithm of spaceborne SAR and can improve processing efficiently. SPECAN algorithm with this method can be used in quick-look imaging.

  12. Quartz red TL SAR equivalent dose overestimation for Chinese loess

    DEFF Research Database (Denmark)

    Lai, Z.P.; Murray, A.S.; Bailey, R.M.;

    2006-01-01

    For the red TL of quartz extracted from Chinese loess, the single-aliquot regenerative-dose (SAR) procedure overestimates the known laboratory doses in dose recovery test. The overestimation is the result of the first heating during the measurement of natural TL signal causing a sensitivity...... reduction, which is not corrected for using a SAR protocol. The SARA procedure was used to measure the sensitivity change. Using this as a correction factor is tested by comparison with the quartz optically stimulated luminiscence (OSL) equivalent dose. SARA is also employed to determine the residual level...... of red TL, which is found to be more than 100 Gy. (c) 2005 Elsevier Ltd. All rights reserved....

  13. Sea ice classification using dual polarization SAR data

    International Nuclear Information System (INIS)

    Sea ice is an indicator of climate change and also a threat to the navigation security of ships. Polarimetric SAR images are useful in the sea ice detection and classification. In this paper, backscattering coefficients and texture features derived from dual polarization SAR images are used for sea ice classification. Firstly, the HH image is recalculated based on the angular dependences of sea ice types. Then the effective gray level co-occurrence matrix (GLCM) texture features are selected for the support vector machine (SVM) classification. In the end, because sea ice concentration can provide a better separation of pancake ice from old ice, it is used to improve the SVM result. This method provides a good classification result, compared with the sea ice chart from CIS

  14. Design and Analysis of HJ-1-C Satellite SAR Antenna

    Directory of Open Access Journals (Sweden)

    Zheng Shi-kun

    2014-06-01

    Full Text Available With truss deployable mesh parabolic reflector, the HJ-1-C SAR antenna has complex structure and multiple steps during the deployed processing. The design of the antenna is difficult in terms of deployed reliability and electrical performance. This paper makes intensive research on system, structure and electrical design, and the analysis of mechanical and thermal performance in the actual space conditions is also presented. The successful deploying in orbit and high image quality of the HJ-1-C satellite indicate that the mechanical, electronic, thermal and reliability design of the antenna satisfy the project requirement, and these research provides valuable experience for the design of the centralized mesh parabolic SAR antenna.

  15. Entropy-based Statistical Analysis of PolSAR Data

    CERN Document Server

    Frery, Alejandro C; Nascimento, Abraão D C

    2012-01-01

    Images obtained from coherent illumination processes are contaminated with speckle noise, with polarimetric synthetic aperture radar (PolSAR) imagery as a prominent example. With an adequacy widely attested in the literature, the scaled complex Wishart distribution is an acceptable model for PolSAR data. In this perspective, we derive analytic expressions for the Shannon, R\\'enyi, and restricted Tsallis entropies under this model. Relationships between the derived measures and the parameters of the scaled Wishart law (i.e., the equivalent number of looks and the covariance matrix) are discussed. In addition, we obtain the asymptotic variances of the Shannon and R\\'enyi entropies when replacing distribution parameters by maximum likelihood estimators. As a consequence, confidence intervals based on these two entropies are also derived and proposed as new ways of capturing contrast. New hypothesis tests are additionally proposed using these results, and their performance is assessed using simulated and real dat...

  16. SARS and MERS: recent insights into emerging coronaviruses.

    Science.gov (United States)

    de Wit, Emmie; van Doremalen, Neeltje; Falzarano, Darryl; Munster, Vincent J

    2016-08-01

    The emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 marked the second introduction of a highly pathogenic coronavirus into the human population in the twenty-first century. The continuing introductions of MERS-CoV from dromedary camels, the subsequent travel-related viral spread, the unprecedented nosocomial outbreaks and the high case-fatality rates highlight the need for prophylactic and therapeutic measures. Scientific advancements since the 2002-2003 severe acute respiratory syndrome coronavirus (SARS-CoV) pandemic allowed for rapid progress in our understanding of the epidemiology and pathogenesis of MERS-CoV and the development of therapeutics. In this Review, we detail our present understanding of the transmission and pathogenesis of SARS-CoV and MERS-CoV, and discuss the current state of development of measures to combat emerging coronaviruses. PMID:27344959

  17. Temporal decorrelation model for the bistatic SAR interferometry

    Institute of Scientific and Technical Information of China (English)

    Qilei Zhang; Wenge Chang

    2015-01-01

    This paper develops a temporal decorrelation model for the bistatic synthetic aperture radar (BSAR) interferometry. The temporal baseline is one of the important decorrelation sources for the repeat-pass synthetic aperture radar (SAR) interferometry. The study of temporal decorrelation is chal enging, especial y for the bistatic configuration, since temporal decorrelation is related to the data acquisition geometry. To develop an appropriate theoretical model for BSAR interferometry, the existing models for monostatic SAR cases are extended, and the general BSAR geometry con-figuration is involved in the derivation. Therefore, the developed temporal decorrelation model can be seen as a general model. The validity of the theoretical model is supported by Monte Carlo simulations. Furthermore, the impacts of the system parameters and BSAR geometry configurations on the temporal decorrelation model are discussed briefly.

  18. MOTION COMPENSATION FOR WIDE BEAM SAR BASED ON FREQUENCY DIVISION

    Institute of Scientific and Technical Information of China (English)

    Zheng Xiaoshuang; Yu Weidong; Li Zaoshe

    2008-01-01

    Aperture-dependent motion compensation is important for wide beam Synthetic Aperture Radar (SAR) data processing. This paper studies a wide beam motion compensation algorithm based on frequency division. It takes blocks along azimuth dimension in frequency domain and applies an-gle-variant motion compensation in time domain. With this frequency division based motion com-pensation approach,the effects of aperture-dependent residual phase errors are corrected precisely. The rationale and procedure of this algorithm are introduced in detail. Point targets and images of a P-band airborne SAR with motion errors are simulated to validate this algorithm. Compared with the wide beam motion compensation algorithms based on time division,the proposed algorithm has better performance,especially in terms of high-frequency motion errors.

  19. SAR IMAGE ENHANCEMENT BASED ON BEAM SHARPENING TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    LIYong; ZI-IANGKun-hui; ZHUDai-yin; ZHUZhao-da

    2004-01-01

    A major problem encountered in enhancing SAR image is the total loss of phase information and the unknown parameters of imaging system. The beam sharpening technique, combined with synthetic aperture radiation pattern estimation provides an approach to process this kind of data to achieve higher apparent resolution. Based on the criterion of minimizing the expected quadratic estimation error, an optimum FIR filter with a symmetrical structure is designed whose coefficients depend on the azimuth response of local isolated prominent points because this response can be approximately regarded as the synthetic aperture radiation pattern of the imaging system. The point target simulation shows that the angular resolution is improved by a ratio of almost two to one. The processing results of a live SAR image demonstrate the validity of the method.

  20. Estimating soil moisture using the Danish polarimetric SAR

    DEFF Research Database (Denmark)

    Jiankang, Ji; Thomsen, A.; Skriver, Henning

    The results of applying data from the Danish polarimetric SAR (EMISAR) to estimate soil moisture for bare fields are presented. Fully calibrated C-band SAR images for hh, vv and cross polarizations have been used in this study. The measured surface roughness data showed that classical roughness...... autocorrelation functions (Gaussian and Exponential) were not able to fit natural surfaces well. A Gauss-Exp hybrid model which agreed better with the measured data has been proposed. Theoretical surface scattering models (POM, IEM), as well as an empirical model for retrieval of soil moisture and surface rms...... height from coand cross-polarized ratio, have been examined, but the results are less satisfactory. As soil moisture response to backscattering coefficient σo is mainly coupled to surface roughness effect for bare fields, a bilinear model coupling volumetric soil moisture mv and surface rms height σ to...

  1. Evaluating the efficiency of TT-OSL SAR protocols

    International Nuclear Information System (INIS)

    Optically Stimulated Luminescence (OSL) dating based on the fast component is now widely used to establish chronologies of sedimentary deposits. Since this component saturates at a relatively low dose, the method is limited to the dating of Late Pleistocene quartz samples. Consequently, dating events beyond this limit is a key challenge. In this context the use of the TT-OSL signal which exhibits a high doses saturation level offers the potential to extend the age range of the method. Since the promising study of Wang et al. (2006b), in which a 780 ka age validated by palaeomagnetism data was reported for a Chinese loess sample, several studies focused on establishing a SAR TT-OSL dating protocol. They suggested applying different kinds of heat treatment at the end of a SAR cycle, as well as two normalisation procedures. The aim of this study was to test the reliability of these protocols for a loess-like Middle Pleistocene sample for which the expected De is known approximatively. We tested four published SAR protocols by implementing the dose recovery tests on artificially bleached quartz aliquots. The results obtained showed a systematic overestimation of the recovered doses and revealed high sensitivity changes between the first (natural) and the following cycles. It is believed that this behaviour is a consequence of the thermal treatment applied at the end of each SAR cycle which is necessary to empty the hard-to-bleach TT-OSL traps. Neither OSL nor TT-OSL signal test dose responses proved suitable to correct this sensitivity change.

  2. The chest X-ray appearances of SARS

    International Nuclear Information System (INIS)

    Objective: To report the chest X-ray appearances of the severe acute respiratory syndrome (SARS). Methods: The chest films of 105 SARS patients were analyzed. All the patients were admitted by our hospital from January 30 to March 31, 2003, and the diagnoses met the diagnostic criterion of IAP made by the Ministry of Public Health, P. R. China. According to their first X-ray film appearances and progression, the patterns of lung lesions were categorized to four types: (1) focal lesion : the single and focal consolidation developed to diffuse lesion. (2) multiple lesions: the first X-ray film showed multiple patchy lesions or/and noodles. (3) interstitial-parenchyma: the major appearance on the first X-ray film was interstitial abnormality, followed by the major parenchymal lesion. (4) interstitial lesion: interstitial abnormality was predominant. Results: The chest radiological appearances of SARS were multiform. 75 cases (57 cases of focal lesion and 18 cases of multiple lesions) showed exudation and consolidation lesions, and 25 cases showed predominant interstitial lesion, followed by the lung consolidation. The interstitial lesions were showed in the other 5 cases , without obvious parenchymal exudation. There was a median interval of 19 days (range 7-46 days) from the onset of abnormality on the first X-ray film to the resolution. Conclusion: The predominant abnormalities of SARS on the first X-ray film were parenchymal exudation or/and interstitial lesion. The lesions progressed quickly at the early stage and reached at a peak within 7-10 days. The lesions in most patients would be fully resolved. Most patients have good prognosis , and sequela haven't been found yet so far

  3. Modeling and public health emergency responses: lessons from SARS.

    Science.gov (United States)

    Glasser, John W; Hupert, Nathaniel; McCauley, Mary M; Hatchett, Richard

    2011-03-01

    Modelers published thoughtful articles after the 2003 SARS crisis, but had limited if any real-time impact on the global response and may even have inadvertently contributed to a lingering misunderstanding of the means by which the epidemic was controlled. The impact of any intervention depends on its efficiency as well as efficacy, and efficient isolation of infected individuals before they become symptomatic is difficult to imagine. Nonetheless, in exploring the possible impact of quarantine, the product of efficiency and efficacy was varied over the entire unit interval. Another mistake was repeatedly fitting otherwise appropriate gamma distributions to times to event regardless of whether they were stationary or not, particularly onset-isolation intervals whose progressive reduction evidently contributed to SARS control. By virtue of their unknown biology, newly-emerging diseases are more challenging than familiar human scourges. Influenza, for example, recurs annually and has been modeled more thoroughly than any other infectious disease. Moreover, models were integrated into preparedness exercises, during which working relationships were established that bore fruit during the 2009 A/H1N1 pandemic. To provide the most accurate and timely advice possible, especially about the possible impact of measures designed to control diseases caused by novel human pathogens, we must appreciate the value and difficulty of policy-oriented modeling. Effective communication of insights gleaned from modeling SARS will help to ensure that policymakers involve modelers in future outbreaks of newly-emerging infectious diseases. Accordingly, we illustrate the increasingly timely care-seeking by which, together with increasingly accurate diagnoses and effective isolation, SARS was controlled via heuristic arguments and descriptive analyses of familiar observations. PMID:21420657

  4. Efficient Evaluation of Fourier-Based SAR Focusing Kernels

    OpenAIRE

    Prats, Pau; Rodriguez-Cassola, Marc; De Zan, Francesco; Lopez-dekker, Paco; Scheiber, Rolf; Reigber, Andreas

    2014-01-01

    This letter addresses the efficient evaluation of Fourier-based kernels for synthetic aperture radar (SAR) image formation. The goal is to evaluate the quality of the focused impulse response function and the residual phase errors of the kernel without having to implement the processor itself nor perform a costly point-target simulation followed by the processing. The proposed methodology is convenient for situations where the assumption of a hyperbolic range history does not hold anymore,...

  5. Investigation on Multimode SAR Imaging Based on Digital Array Radar

    OpenAIRE

    Li Xue-shi; Sun Guang-cai; Shao Peng; Wu Yu-feng; Xing Meng-dao

    2014-01-01

    Digital Array Radar (DAR) has the ability of simultaneous multimode imaging and has many potential applications. This paper firstly introduces the basic hardware structure and the operation principle of DAR. Combined with the Digital BeamForming (DBF) technique, six operational modes that can be used in multimode Synthetic Aperture Radar (SAR) imaging are proposed, and the corresponding novel imaging modes are produced. Moreover, the design of the novel imaging modes is introduced in detail. ...

  6. Digital Beamforming: A Paradigm Shift for Spaceborne SAR

    OpenAIRE

    Moreira, Alberto

    2013-01-01

    Spaceborne Synthetic Aperture Radar (SAR) provides high-resolution, day-and-night and weather-independent images for a multitude of applications ranging from geoscience and climate change research, environmental monitoring, global 2-D and 3-D mapping, change detection, 4-D mapping (space and time), security-related applications up to planetary exploration. By means of the development of new digital beamforming and waveform diversity technologies in combination with large reflector antennas, f...

  7. System Concepts for Bi- and Multi-Static SAR Missions

    OpenAIRE

    Krieger, Gerhard; Fiedler, Hauke; Rodriguez Cassola, Marc; Hounam, David; Moreira, Alberto

    2003-01-01

    The performance and capabilities of bi- and multistatic spaceborne synthetic aperture radar (SAR) are analyzed. Such systems can be optimized for a broad range of applications like frequent monitoring, wide swath imaging, single-pass cross-track interferometry, along-track interferometry, resolution enhancement or radar tomography. Further potentials arises from digital beamforming on receive, which allows to gather additional information about the direction of the scattered radar echoes. Thi...

  8. Multifrequency OFDM SAR in Presence of Deception Jamming

    OpenAIRE

    Schuerger Jonathan; Garmatyuk Dmitriy

    2010-01-01

    Orthogonal frequency division multiplexing (OFDM) is considered in this paper from the perspective of usage in imaging radar scenarios with deception jamming. OFDM radar signals are inherently multifrequency waveforms, composed of a number of subbands which are orthogonal to each other. While being employed extensively in communications, OFDM has not found comparatively wide use in radar, and, particularly, in synthetic aperture radar (SAR) applications. In this paper, we aim to show the adv...

  9. Motion Compensation for Aircraft-Borne Interferometric SAR

    OpenAIRE

    Bullock, R J

    2003-01-01

    This research has studied data driven techniques for roll compensation for aircraft-borne InSAR, for platforms where an accurate Inertial Navigation Unit (INU) is inappropriate due to limitations on weight or cost, such as a low-cost civilian mapping system or a miniature UAV. It is shown that for unknown topography, roll errors cannot simply be filtered from the interferogram due to a fundamental ambiguity between aircraft roll effects and certain types of undulating terrain. ...

  10. Enhancement on spotlight COSMO-SkyMed SAR products

    Science.gov (United States)

    Lorusso, R.; Milillo, G.

    2015-10-01

    COSMO-SkyMed (CSK) satellites are providing images with a resolution in the meter regime using the sliding spotlight mode (SL). This is an imaging mode which can obtain better azimuth resolution at the expense of azimuth imaged area than stripmap mode .Spotlight SAR data processing is already an established topic; efficient and accurate solutions in frequency domain have been proposed over the last years. However, the assumptions of these algorithms start to be invalid when applied to high-resolution spotlight SAR data acquired in spaceborne low Earth orbit (LEO) configurations. The assumption of a hyperbolic range history is no longer accurate for sub-metric spatial resolutions due to the satellite curved orbit. Since velocity of a space-borne platform is quite uniform, a simple focusing scheme had been designed in order to handle no straight line trajectory, using both approximated and accurate ω-k focusing kernel. Moreover, when getting close to decimeter resolution (at X-band) other several effects appear; in particular the motion of the satellite during the transmission and reception of the chirp signal deteriorate the impulse response function (IRF), if not properly considered (so called stop-and-go approximation). This paper shows that also CSK SL SAR data, with a resolution close to 1 meter, are not immune to disturbance effects when the stop-and-go approximation is assumed. The ω-k algorithm with satellite curved orbit handling is used to focus CSK spotlight data, and the stop-and-go approximation correction is included in the data processing chain. Experimental results with CSK spotlight data are provided to show quality enhancement on SAR standard focused products.

  11. Synthesis, SAR and antibacterial studies on novel chalcone oxazolidinone hybrids.

    Science.gov (United States)

    Selvakumar, N; Kumar, G Sunil; Azhagan, A Malar; Rajulu, G Govinda; Sharma, Shikha; Kumar, M Sitaram; Das, Jagattaran; Iqbal, Javed; Trehan, Sanjay

    2007-04-01

    With an intention to synergise the antibacterial activity of chalcones and oxazolidinones, several hybrid compounds possessing both chalcone and oxazolidinone moieties were synthesized and tested for antibacterial activity. The hybrid molecules containing heterocycles instead of aromatic ring were found to be active. A SAR study with various heterocycles resulted in a lead molecule 20, which was converted to one of the potent antibacterial compounds 27. PMID:17150281

  12. GNSS-based bistatic SAR: a signal processing view

    Science.gov (United States)

    Antoniou, Michail; Cherniakov, Mikhail

    2013-12-01

    This article presents signal processing algorithms used as a new remote sensing tool, that is passive bistatic SAR with navigation satellites (e.g. GPS, GLONASS or Galileo) as transmitters of opportunity. Signal synchronisation and image formation algorithms are described for two system variants: one where the receiver is moving and one where it is fixed on the ground. The applicability and functionality of the algorithms described is demonstrated through experimental imagery that ultimately confirms the feasibility of the overall technology.

  13. SAR-Based Wind Resource Statistics in the Baltic Sea

    Directory of Open Access Journals (Sweden)

    Alfredo Peña

    2011-01-01

    Full Text Available Ocean winds in the Baltic Sea are expected to power many wind farms in the coming years. This study examines satellite Synthetic Aperture Radar (SAR images from Envisat ASAR for mapping wind resources with high spatial resolution. Around 900 collocated pairs of wind speed from SAR wind maps and from 10 meteorological masts, established specifically for wind energy in the study area, are compared. The statistical results comparing in situ wind speed and SAR-based wind speed show a root mean square error of 1.17 m s−1, bias of −0.25 m s−1, standard deviation of 1.88 m s−1 and correlation coefficient of R2 0.783. Wind directions from a global atmospheric model, interpolated in time and space, are used as input to the geophysical model function CMOD-5 for SAR wind retrieval. Wind directions compared to mast observations show a root mean square error of 6.29° with a bias of 7.75°, standard deviation of 20.11° and R2 of 0.950. The scale and shape parameters, A and k, respectively, from the Weibull probability density function are compared at only one available mast and the results deviate ~2% for A but ~16% for k. Maps of A and k, and wind power density based on more than 1000 satellite images show wind power density values to range from 300 to 800 W m−2 for the 14 existing and 42 planned wind farms.

  14. Nano(Q)SAR: Challenges, pitfalls and perspectives

    OpenAIRE

    Tantra, R; Oksel, C; Puzyn, T; Wang, J; Robinson, KN; Wang, XZ; Ma, CY; Wilkins, T

    2015-01-01

    Regulation for nanomaterials is urgently needed, and the drive to adopt an intelligent testing strategy is evident. Such a strategy will not only provide economic benefits but will also reduce moral and ethical concerns arising from animal testing. For regulatory purposes, such an approach is promoted by REACH, particularly the use of quantitative structure–activity relationships [(Q)SAR] as a tool for the categorisation of compounds according to their physicochemical and toxicological proper...

  15. Reflectors for SAR performance testing-second edition

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    Synthetic Aperture Radar (SAR) performance testing and estimation is facilitated by observing the system response to known target scene elements. Trihedral corner reflectors and other canonical targets play an important role because their Radar Cross Section (RCS) can be calculated analytically. However, reflector orientation and the proximity of the ground and mounting structures can significantly impact the accuracy and precision with which measurements can be made. These issues are examined in this report.

  16. A low-power SAR ADC for IRFPA ROIC

    Science.gov (United States)

    Gao, Lei; Ding, Ruijun; Zhou, Jie; Wang, Pan; Chen, Guoqiang

    2012-12-01

    This paper presents a low power ADC for the 512*512 infrared focal plane arrays (IRFPA) readout integrated circuit(ROIC). The major structure, the working mode and the simulation result of the readout integrated circuit are shown in this paper. The power supply voltage of 0.35μm standard CMOS process is 3.3V in this design, and then the output range of the Direct Injection (DI) input circuit is reached 2V. Successive-approximation-register (SAR) ADC architecture is used in this readout integrated circuit. And each ADC is shared by one column of the IRFPA. This SAR ADC is made up of a 13-bit digital-analog converter (DAC), a high resolution comparator, and a digital control circuit. The most important part is the voltage-scaling and charge-scaling charge redistribution DAC. In this DAC, charge scaling with a capacitor ladder to determine the least significant bits is combined with voltage scaling with a resister ladder to determine the most significant bits. The comparator uses three-stage operational amplifier structure to get a 77dB differential gain. The Common-Mode input rang of the comparator is 1V to 3V, and minimum resolvable voltage difference is 0.3mV. This SAR ADC has some advantages, especially in low power and high speed. The simulation result shows that the resolution of the ADC is 12 bit and the conversion time of the ADC is 6.5μs, while the power of each ADC is as low as 300μW. Finally, this SAR ADC can satisfy the request of 512*512 IRFPAs ROIC with a 100Hz frame rate.

  17. Mars Mission Concepts: SAR and Solar Electric Propulsion

    Science.gov (United States)

    Elsperman, M.; Klaus, K.; Smith, D. B.; Clifford, S. M.; Lawrence, S. J.

    2012-12-01

    Introduction: The time has come to leverage technology advances (including advances in autonomous operation and propulsion technology) to reduce the cost and increase the flight rate of planetary missions, while actively developing a scientific and engineering workforce to achieve national space objectives. Mission Science at Mars: A SAR imaging radar offers an ability to conduct high resolution investigations of the shallow (craft for multiple missions reduces costs. Solar electric propulsion (SEP) provides the flexibility required for multiple mission objectives. SEP provides the greatest payload advantage albeit at the sacrifice of mission time. Our concept involves using a SEP enabled space craft (Boeing 702SP) with a highly capable SAR imager that also conducts autonomous rendezvous and docking experiments accomplished from Mars orbit. Our concept of operations is to launch on May 5, 2018 using a launch vehicle with 2000kg launch capacity with a C3 of 7.4. After reaching Mars it takes 145 days to spiral down to a 250 km orbit above the surface of Mars when Mars SAR operations begin. Summary/Conclusions: A robust and compelling Mars mission can be designed to meet the 2018 Mars launch window opportunity. Using advanced in-space power and propulsion technologies like High Power Solar Electric Propulsion provides enormous mission flexibility to execute the baseline science mission and conduct necessary Mars Sample Return Technology Demonstrations in Mars orbit on the same mission. An observation spacecraft platform like the high power (~5Kw) 702SP at Mars also enables the use of a SAR instrument to reveal new insights and understanding of the Mars regolith for both science and future manned exploration and utilization.

  18. Karakterizacija polarimetrijskih SAR slika velike rezolucije tehnikama slijepog razdvajanja izvora

    OpenAIRE

    Besic, Nikola

    2014-01-01

    This thesis comprises two research axes. The first, being rather methodological, consists of our efforts to answer some of the open questions in the POLSAR community, while the latter is sooner related to the specific application - the remote sensing of snow.Following the alternative statistical modelling of highly textured multivariate SAR datasets by means of SIRV model, we propose the appropriate assessment of, otherwise assumed, cir- cularity and sphericity parameters. The last is coupled...

  19. A Strategy Toward Convergent Combination Immunotherapy for SARS

    Institute of Scientific and Technical Information of China (English)

    Wayne; A.; Marasco

    2005-01-01

    Passive Immunotherapyfor viral infections withimmune humanimmunoglobulin has been usedfor many yearsinthe pro-phylaxis andtreatment of infectious disease such as RSV,CMV,rabies,hepatitis Aand B and others.Recently,ad-vances in antibody engineering have allowedthe rapid isolation and pre-clinical development of human monoclonal anti-bodies(Mab)for the treatment of humaninfectious diseases and other conditions.We have explored the use of humanmonoclonal antibodies against the newly emerged SARS coronavirus(Co...

  20. Feature-Area Optimization: A Novel SAR Image Registration Method

    OpenAIRE

    Liu, Fuqiang; Bi, Fukun; Chen, Liang; Shi, Hao; Liu, Wei

    2016-01-01

    This letter proposes a synthetic aperture radar (SAR) image registration method named Feature-Area Optimization (FAO). First, the traditional area-based optimization model is reconstructed and decomposed into three key but uncertain factors: initialization, slice set and regularization. Next, structural features are extracted by scale invariant feature transform (SIFT) in dual-resolution space (SIFT-DRS), a novel SIFT-Like method dedicated to FAO. Then, the three key factors are determined ba...

  1. Polarimetric SAR Image Supervised Classification Method Integrating Eigenvalues

    OpenAIRE

    Xing Yanxiao; Zhang Yi; Li Ning; Wang Yu; Hu Guixiang

    2016-01-01

    Since classification methods based on H/α space have the drawback of yielding poor classification results for terrains with similar scattering features, in this study, we propose a polarimetric Synthetic Aperture Radar (SAR) image classification method based on eigenvalues. First, we extract eigenvalues and fit their distribution with an adaptive Gaussian mixture model. Then, using the naive Bayesian classifier, we obtain preliminary classification results. The distribution of eigenvalues in ...

  2. Coastal and Wetlands Applications for an InSAR Mission

    Science.gov (United States)

    Dixon, T.; Amelung, F.; Gourmelen, N.; Kim, S.; Osmanoglu, B.; Wdowinski, S.

    2006-12-01

    Interferometric Synthetic Aperture Radar (InSAR) has found wide application in the study of Earth surface change, including earthquake and volcano deformation, motion of glaciers and ice sheets, and ground subsidence due to fluid extraction. In the last few years, InSAR may have significant application in studies of wetlands, coastal regions, and related environmental problems. These are becoming increasingly important as global warming contributes to sea level rise, with consequent modification or loss of coastal habitat, and increased storm frequency/intensity, with consequent increased hazard to coastal communities. Most of these applications would benefit from increased data availability and spatial resolution. A common problem for many InSAR studies in these areas is the influence of spatially and temporally variable tropospheric water vapor. Multiple interferograms can be used to average down tropospheric noise, or selectively edit image pairs where tropospheric noise is high. Alternately, the Permanent Scatterer (PSInSAR) technique can produce an average surface change rate over several months or years for coastal land applications where the assumption of steady state deformation is reasonable (e.g., some land subsidence applications). This technique also effectively identifies tropospheric noise. Common to both approaches is the need for large numbers of images, closely spaced in time. Wetland water levels also change on short time scales (days to weeks) implying the need for frequent coverage. Hence, such applications benefit from mission scenarios emphasizing repeat times shorter than 7 days. Assuming global coverage is desirable, the requirement for rapid re-survey suggests that multi-satellite constellations should be considered.

  3. Establishment of management information system for SARS surveillance and control in Shaanxi province of China

    Institute of Scientific and Technical Information of China (English)

    JIANG Jian-hui; QU Jing-hui; XU De-zhong; YAN Yong-ping; ZHANG Zhi-ying; ZHANG Heng; WEN Liang

    2005-01-01

    Objective: To develop the management information system for SARS surveillance and control in Shaanxi province of China responding to the urgent needs for preventing and curing SARS disease.Methods: Based on geographic information system technology, the management information system for SARS disease in Shaanxi province of China was established using "SuperMap Objects 3.0" GIS development platform and Delphi 7.0. Results: The following functions were implemented in the system: the realtime collection and monitoring, management and analysis, dissemination of SARS disease information, and assistant decision-making support for prevention against SARS disease. Conclusion: The system that integrates epidemiology theories and GIS techniques together can provide a scientific, efficient means for monitoring, prevention of SARS disease in the future.

  4. 3-D SAR image formation from sparse aperture data using 3-D target grids

    Science.gov (United States)

    Bhalla, Rajan; Li, Junfei; Ling, Hao

    2005-05-01

    The performance of ATR systems can potentially be improved by using three-dimensional (3-D) SAR images instead of the traditional two-dimensional SAR images or one-dimensional range profiles. 3-D SAR image formation of targets from radar backscattered data collected on wide angle, sparse apertures has been identified by AFRL as fundamental to building an object detection and recognition capability. A set of data has been released as a challenge problem. This paper describes a technique based on the concept of 3-D target grids aimed at the formation of 3-D SAR images of targets from sparse aperture data. The 3-D target grids capture the 3-D spatial and angular scattering properties of the target and serve as matched filters for SAR formation. The results of 3-D SAR formation using the backhoe public release data are presented.

  5. Automatic Registration of SAR Images with the Integrated Complementary Invariant Feature

    Directory of Open Access Journals (Sweden)

    Xiao-hua Wang

    2014-01-01

    Full Text Available The accurate Synthetic Aperture Radar (SAR image registration is important for exact analyses of mine deformation and ecological environment change. Currently, many image registration algorithms have been proposed, but these registration algorithms cannot be directly applied to SAR image, so an integrated registration approach is presented in this paper. Firstly, it is the coarse matching with Canny edge dividing regions; secondly, it is the fine matching by SIFT algorithm with improved Canny edge features; finally, obtain accurate registration SAR image. This approach has fewer computations than that simply using SIFT feature matching. Experimental analyses with SAR images of Yanzhou Mine demonstrate the efficiency and the accuracy of this approach for mine SAR image registration, which provides a simple and effective tool in SAR monitoring of mining deformation and ecological changes

  6. Advances in space-borne SAR interferometry and its application to ground deformation monitoring

    Institute of Scientific and Technical Information of China (English)

    LIU Zhen-guo; BIAN Zheng-fu

    2011-01-01

    The development of Differential Synthetic Aperture Radar Interferometry (D-InSAR), in terms of its evolution from classic to advanced forms, such as Least-Squares approach, Permanent Scatterer Interferometry, Small Baseline Subset, and Coherent Pixel Technique, is reviewed, describing concisely the main principles of each method and highlighting the difference and relationship between them. Applications of InSAR technology in China were then introduced, together with the obstacles to overcome and feasible strategies, such as integrating MERIS/MODIS data to compensate for the atmospheric effect and GPS, and multi-platform SAR data to make InSAR technique practical and operational under various conditions. The latest developments were then analyzed along with high-quality SAR data, available thanks to the newly launched high-tech satellites, TerraSAR-X, and Cosmo Sky-med, and conclusions were drawn about the main limitations of the technique.

  7. Estimation of Boreal Forest Biomass Using Spaceborne SAR Systems

    Science.gov (United States)

    Saatchi, Sassan; Moghaddam, Mahta

    1995-01-01

    In this paper, we report on the use of a semiempirical algorithm derived from a two layer radar backscatter model for forest canopies. The model stratifies the forest canopy into crown and stem layers, separates the structural and biometric attributes of the canopy. The structural parameters are estimated by training the model with polarimetric SAR (synthetic aperture radar) data acquired over homogeneous stands with known above ground biomass. Given the structural parameters, the semi-empirical algorithm has four remaining parameters, crown biomass, stem biomass, surface soil moisture, and surface rms height that can be estimated by at least four independent SAR measurements. The algorithm has been used to generate biomass maps over the entire images acquired by JPL AIRSAR and SIR-C SAR systems. The semi-empirical algorithms are then modified to be used by single frequency radar systems such as ERS-1, JERS-1, and Radarsat. The accuracy. of biomass estimation from single channel radars is compared with the case when the channels are used together in synergism or in a polarimetric system.

  8. Wavelet Analysis of SAR Images for Coastal Monitoring

    Science.gov (United States)

    Liu, Antony K.; Wu, Sunny Y.; Tseng, William Y.; Pichel, William G.

    1998-01-01

    The mapping of mesoscale ocean features in the coastal zone is a major potential application for satellite data. The evolution of mesoscale features such as oil slicks, fronts, eddies, and ice edge can be tracked by the wavelet analysis using satellite data from repeating paths. The wavelet transform has been applied to satellite images, such as those from Synthetic Aperture Radar (SAR), Advanced Very High-Resolution Radiometer (AVHRR), and ocean color sensor for feature extraction. In this paper, algorithms and techniques for automated detection and tracking of mesoscale features from satellite SAR imagery employing wavelet analysis have been developed. Case studies on two major coastal oil spills have been investigated using wavelet analysis for tracking along the coast of Uruguay (February 1997), and near Point Barrow, Alaska (November 1997). Comparison of SAR images with SeaWiFS (Sea-viewing Wide Field-of-view Sensor) data for coccolithophore bloom in the East Bering Sea during the fall of 1997 shows a good match on bloom boundary. This paper demonstrates that this technique is a useful and promising tool for monitoring of coastal waters.

  9. Multifrequency OFDM SAR in Presence of Deception Jamming

    Directory of Open Access Journals (Sweden)

    Schuerger Jonathan

    2010-01-01

    Full Text Available Orthogonal frequency division multiplexing (OFDM is considered in this paper from the perspective of usage in imaging radar scenarios with deception jamming. OFDM radar signals are inherently multifrequency waveforms, composed of a number of subbands which are orthogonal to each other. While being employed extensively in communications, OFDM has not found comparatively wide use in radar, and, particularly, in synthetic aperture radar (SAR applications. In this paper, we aim to show the advantages of OFDM-coded radar signals with random subband composition when used in deception jamming scenarios. Two approaches to create a radar signal by the jammer are considered: instantaneous frequency (IF estimator and digital-RF-memory- (DRFM- based reproducer. In both cases, the jammer aims to create a copy of a valid target image via resending the radar signal at prescribed time intervals. Jammer signals are derived and used in SAR simulations with three types of signal models: OFDM, linear frequency modulated (LFM, and frequency-hopped (FH. Presented results include simulated peak side lobe (PSL and peak cross-correlation values for random OFDM signals, as well as simulated SAR imagery with IF and DRFM jammers'-induced false targets.

  10. Efficient sliding spotlight SAR raw signal simulation of extended scenes

    Directory of Open Access Journals (Sweden)

    Huang Pingping

    2011-01-01

    Full Text Available Abstract Sliding spotlight mode is a novel synthetic aperture radar (SAR imaging scheme with an achieved azimuth resolution better than stripmap mode and ground coverage larger than spotlight configuration. However, its raw signal simulation of extended scenes may not be efficiently implemented in the two-dimensional (2D Fourier transformed domain. This article presents a novel sliding spotlight raw signal simulation approach from the wide-beam SAR imaging modes. This approach can generate sliding spotlight raw signal not only from raw data evaluated by the simulators, but also from real data in the stripmap/spotlight mode. In order to obtain the desired raw data from conventional stripmap/spotlight mode, the azimuth time-varying filtering, which is implemented by de-rotation and low-pass filtering, is adopted. As raw signal of extended scenes in the stripmap/spotlight mode can efficiently be evaluated in the 2D Fourier domain, the proposed approach provides an efficient sliding spotlight SAR simulator of extended scenes. Simulation results validate this efficient simulator.

  11. Land subsidence monitoring by D-InSAR technique

    Institute of Scientific and Technical Information of China (English)

    Fan Hongdong; Deng Kazhong; Ju Chengyu; Zhu Chuanguang; Xue Jiqun

    2011-01-01

    Nowadays,the researches of using Differential Interferometric Synthetic Aperture Radar (D-InSAR) technique to monitor the land subsidence are mainly on how to qualitatively analyze the subsidence areas and values,but the analysis of subsidence process and mechanism are insufficient.In order to resolve these problems,6 scenes of ERS1/2 images captured during 1995 and 2000 in a certain place of Jiangsu province were selected to obtain the subsidence and velocities in three time segments by “two-pass” DInSAR method.Then the relationships among distributions of pumping wells,exploitation quantity of groundwater,and confined water levels were studied and the subsidence mechanism was systematically analyzed.The results show that using D-InSAR technique to monitor the deformation of large area can obtain high accuracies,the disadvantages of classical observation methods can be remedied and there is a linear relationship among the velocities of land subsidence,the water level and the exploitation quantity.

  12. Target detection and recognition in SAR imagery based on KFDA

    Institute of Scientific and Technical Information of China (English)

    Fei Gao; Jingyuan Mei; Jinping Sun; Jun Wang; Erfu Yang; Amir Hussain

    2015-01-01

    Current research on target detection and recognition from synthetic aperture radar (SAR) images is usual y carried out separately. It is difficult to verify the ability of a target recognition algorithm for adapting to changes in the environment. To realize the whole process of SAR automatic target recognition (ATR), es-pecial y for the detection and recognition of vehicles, an algorithm based on kernel fisher discriminant analysis (KFDA) is proposed. First, in order to make a better description of the difference be-tween the background and the target, KFDA is extended to the detection part. Image samples are obtained with a dual-window approach and features of the inner and outer window samples are extracted by using KFDA. The difference between the features of inner and outer window samples is compared with a threshold to determine whether a vehicle exists. Second, for the target area, we propose an improved KFDA-IMED (image Euclidean distance) combined with a support vector machine (SVM) to recognize the vehicles. Experimental results validate the performance of our method. On the detection task, our proposed method obtains not only a high detection rate but also a low false alarm rate without using any prior information. For the recognition task, our method overcomes the SAR image aspect angle sensitivity, reduces the requirements for image preprocessing and improves the recogni-tion rate.

  13. Forest Biomass Retrieval from Digital Beamforming SAR (DBSAR)

    Science.gov (United States)

    Rincon, R.; Fatoyinbo, T. E.; Sun, G.; Ranson, J.

    2010-12-01

    We present ongoing research efforts at NASA/Goddard Space Flight Center (GSFC)to retrieve forest biomass using the GSFC digital beamforming SAR (DBSAR). DBSAR is a state-of-the-art multimode radar system designed for the development, implementation, and testing of advanced radar applications. The system combines phased-array architecture, reconfigurable hardware, and on-board processing in order to enable new remote sensing capabilities in support of Earth science and planetary applications. DBSAR is capable of synthesizing multiple antenna beams simultaneously over a large field of view permitting the implementation of SAR imaging techniques. We present the first processed and calibrated DBSAR images retrieved during the 2008 field campaign over the DelMarVa Pensinsula. The aim of our study is to develop biomass measurement and data fusion algorithms and calibration and validation data for current and future spaceborne SAR missions. In this presentation, we show examples of biomass retrieval and radar/lidar data fusion from DBSAR using ground truth data, ALOS/PALSAR and IceSat/GLAS with detailed analysis of the sources of uncertainty associated with DBSAR biomass retrieval, including image processing and field data collection methods.

  14. Multifrequency OFDM SAR in Presence of Deception Jamming

    Science.gov (United States)

    Schuerger, Jonathan; Garmatyuk, Dmitriy

    2010-12-01

    Orthogonal frequency division multiplexing (OFDM) is considered in this paper from the perspective of usage in imaging radar scenarios with deception jamming. OFDM radar signals are inherently multifrequency waveforms, composed of a number of subbands which are orthogonal to each other. While being employed extensively in communications, OFDM has not found comparatively wide use in radar, and, particularly, in synthetic aperture radar (SAR) applications. In this paper, we aim to show the advantages of OFDM-coded radar signals with random subband composition when used in deception jamming scenarios. Two approaches to create a radar signal by the jammer are considered: instantaneous frequency (IF) estimator and digital-RF-memory- (DRFM-) based reproducer. In both cases, the jammer aims to create a copy of a valid target image via resending the radar signal at prescribed time intervals. Jammer signals are derived and used in SAR simulations with three types of signal models: OFDM, linear frequency modulated (LFM), and frequency-hopped (FH). Presented results include simulated peak side lobe (PSL) and peak cross-correlation values for random OFDM signals, as well as simulated SAR imagery with IF and DRFM jammers'-induced false targets.

  15. The Application of PRF Variation to Squint Spotlight SAR

    Directory of Open Access Journals (Sweden)

    Luo Xiu-lian

    2015-02-01

    Full Text Available This paper focuses on a novel squint spotlight SAR mode, where the PRI variation is employed to increase the range swath width, especially for high-resolution imaging. The spotlight SAR is developed to increase the azimuth resolution via steering the antenna beam to always illuminate the same area on the ground during the whole data acquisition interval. However, requirement of high resolution and large squint angle leads to large Range Cell Migration (RCM. Therefore, to ensure the scattered echoes along the azimuth to be completely received within the fixed reception window, the range swath has to be much narrower than the reception window. In order to increase the range swath, we can change the PRI along the azimuth to shift the reception window according to the variation of instantaneous slant range. This paper first derives the PRI variation scheme. Afterward, a modified time-domain Back-Projection Algorithm (BPA is presented to implement the focusing. Finally, simulation results are given to validate the presented SAR mode and corresponding imaging processor.

  16. Dissection of SARS Coronavirus Spike Protein into Discrete Folded Fragments

    Institute of Scientific and Technical Information of China (English)

    LI Shuang; CAI Zhen; CHEN Yong; LIN Zhanglin

    2006-01-01

    The spike protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) mediates cell fusion by binding to target cell surface receptors. This paper reports a simple method for dissecting the viral protein and for searching for foldable fragments in a random but systematic manner. The method involves digestion by DNase I to generate a pool of short DNA segments, followed by an additional step of reassembly of these segments to produce a library of DNA fragments with random ends but controllable lengths. To rapidly screen for discrete folded polypeptide fragments, the reassembled gene fragments were further cloned into a vector as N-terminal fusions to a folding reporter gene which was a variant of green fluorescent protein. Two foldable fragments were identified for the SARS-CoV spike protein, which coincide with various anti-SARS peptides derived from the hepated repeat (HR) region 2 of the spike protein. The method should be applicable to other viral proteins to isolate antigen or vaccine candidates, thus providing an alternative to the full-length proteins (subunits) or linear short peptides.

  17. Human factors engineering checklists for application in the SAR process

    Energy Technology Data Exchange (ETDEWEB)

    Overlin, T.K.; Romero, H.A.; Ryan, T.G.

    1995-03-01

    This technical report was produced to assist the preparers and reviewers of the human factors portions of the SAR in completing their assigned tasks regarding analysis and/or review of completed analyses. The checklists, which are the main body of the report, and the subsequent tables, were developed to assist analysts in generating the needed analysis data to complete the human engineering analysis for the SAR. The technical report provides a series of 19 human factors engineering (HFE) checklists which support the safety analyses of the US Department of Energy`s (DOE) reactor and nonreactor facilities and activities. The results generated using these checklists and in the preparation of the concluding analyses provide the technical basis for preparing the human factors chapter, and subsequent inputs to other chapters, required by DOE as a part of the safety analysis reports (SARs). This document is divided into four main sections. The first part explains the origin of the checklists, the sources utilized, and other information pertaining to the purpose and scope of the report. The second part, subdivided into 19 sections, is the checklists themselves. The third section is the glossary which defines terms that could either be unfamiliar or have specific meanings within the context of these checklists. The final section is the subject index in which the glossary terms are referenced back to the specific checklist and page the term is encountered.

  18. Ocean Wave Parameters Retrieval from Sentinel-1 SAR Imagery

    Directory of Open Access Journals (Sweden)

    Weizeng Shao

    2016-08-01

    Full Text Available In this paper, a semi-empirical algorithm for significant wave height (Hs and mean wave period (Tmw retrieval from C-band VV-polarization Sentinel-1 synthetic aperture radar (SAR imagery is presented. We develop a semi-empirical function for Hs retrieval, which describes the relation between Hs and cutoff wavelength, radar incidence angle, and wave propagation direction relative to radar look direction. Additionally, Tmw can be also calculated through Hs and cutoff wavelength by using another empirical function. We collected 106 C-band stripmap mode Sentinel-1 SAR images in VV-polarization and wave measurements from in situ buoys. There are a total of 150 matchup points. We used 93 matchups to tune the coefficients of the semi-empirical algorithm and the rest 57 matchups for validation. The comparison shows a 0.69 m root mean square error (RMSE of Hs with a 18.6% of scatter index (SI and 1.98 s RMSE of Tmw with a 24.8% of SI. Results indicate that the algorithm is suitable for wave parameters retrieval from Sentinel-1 SAR data.

  19. Coastal wave field extraction using TerraSAR-X data

    Science.gov (United States)

    Bruck, Miguel; Lehner, Susanne

    2013-01-01

    The main highlights of TerraSAR-X (TS-X) synthetic aperture radar (SAR) imagery are a higher resolution of up to 1 m, when compared to conventional C-band SAR data, and a reduction of nonlinear imaging effects of a moving target by lower platform altitude. Thus, ocean waves with wavelength TS-X particularly useful to observe coastal areas where complex bathymetry strongly impacts the approaching waves. TS-X images acquired in different coastal areas are presented, including three case studies at the German coast. Wave fields (significant wave height and peak wavelength) are derived from the TS-X imagery using the proposed XWAVE algorithm and compared not only to in situ buoy wave measurements but also to results of a high-resolution numerical wave model. The objective is to study the quality of significant wave height field estimation in the spatial domain in highly variable conditions, which are typically dominant in coastal areas. The results show that the empirical XWAVE algorithm allows estimating wave fields from TS-X data with high resolution, thus showing the spatial information on wave variations. Therefore, it is a new useful tool to characterize sea state in coastal areas by remote sensing.

  20. Human factors engineering checklists for application in the SAR process

    International Nuclear Information System (INIS)

    This technical report was produced to assist the preparers and reviewers of the human factors portions of the SAR in completing their assigned tasks regarding analysis and/or review of completed analyses. The checklists, which are the main body of the report, and the subsequent tables, were developed to assist analysts in generating the needed analysis data to complete the human engineering analysis for the SAR. The technical report provides a series of 19 human factors engineering (HFE) checklists which support the safety analyses of the US Department of Energy's (DOE) reactor and nonreactor facilities and activities. The results generated using these checklists and in the preparation of the concluding analyses provide the technical basis for preparing the human factors chapter, and subsequent inputs to other chapters, required by DOE as a part of the safety analysis reports (SARs). This document is divided into four main sections. The first part explains the origin of the checklists, the sources utilized, and other information pertaining to the purpose and scope of the report. The second part, subdivided into 19 sections, is the checklists themselves. The third section is the glossary which defines terms that could either be unfamiliar or have specific meanings within the context of these checklists. The final section is the subject index in which the glossary terms are referenced back to the specific checklist and page the term is encountered

  1. InSAR and Numeric Modeling for Land Subsidence

    Science.gov (United States)

    Wulamu, A.; Grzovic, M.

    2015-12-01

    Monitoring land subsidence due to coal mining is a function of several controlling factors, including: depth of the mine, stratigraphy, presence or absence of faults, thickness of mineral seam, mining method used, and hydrogeological conditions. Numerical modeling, e.g., finite element modeling (FEM), provides a comprehensive tool to simulate three-dimensional deformation at specific locations. The basis of the FEM is the representation of a body or a structure by an assemblage of subdivisions called finite elements, which requires the availability of site specific environmental and physical characteristics. The lack of availability of the necessary data leads to large uncertainties in subsidence estimates. With the use of InSAR, many of the needed controlling parameters for improving mine subsidence rate estimates can be identified. Coupling InSAR with FEM can further improve subsidence rate estimates through additional analysis yielding information on the relative importance of various controlling parameters contributing to the mine subsidence, the key mechanisms of failure associated with these parameters, and the surface expressions of these processes. In this contribution, we show that utilizing InSAR and FEM leads to an overall enhanced understanding of mine behavior, including the physical mechanisms that lead to mine subsidence through understanding the rheological behavior of the material over the mine in response to wide range of physical and environmental conditions.

  2. Land Cover Mapping Using SENTINEL-1 SAR Data

    Science.gov (United States)

    Abdikan, S.; Sanli, F. B.; Ustuner, M.; Calò, F.

    2016-06-01

    In this paper, the potential of using free-of-charge Sentinel-1 Synthetic Aperture Radar (SAR) imagery for land cover mapping in urban areas is investigated. To this aim, we use dual-pol (VV+VH) Interferometric Wide swath mode (IW) data collected on September 16th 2015 along descending orbit over Istanbul megacity, Turkey. Data have been calibrated, terrain corrected, and filtered by a 5x5 kernel using gamma map approach. During terrain correction by using a 25m resolution SRTM DEM, SAR data has been resampled resulting into a pixel spacing of 20m. Support Vector Machines (SVM) method has been implemented as a supervised pixel based image classification to classify the dataset. During the classification, different scenarios have been applied to find out the performance of Sentinel-1 data. The training and test data have been collected from high resolution image of Google Earth. Different combinations of VV and VH polarizations have been analysed and the resulting classified images have been assessed using overall classification accuracy and Kappa coefficient. Results demonstrate that, combining opportunely dual polarization data, the overall accuracy increases up to 93.28% against 73.85% and 70.74% of using individual polarization VV and VH, respectively. Our preliminary analysis points out that dual polarimetric Sentinel-1SAR data can be effectively exploited for producing accurate land cover maps, with relevant advantages for urban planning and management of large cities.

  3. Aoutomatic Oil Spill Detection Using TerraSAR-X Data

    Science.gov (United States)

    Zulipiye, Kaiyoumu; Balik Sanli, Fusun

    2016-07-01

    Oil release into the ocean may affect marine ecosystems and cause environmental pollution. Thus, oil spill detection and identification becomes critical important. Characterized by synoptic view over large regions, remote sensing has been proved to be a reliable tool for oil spill detection. Synthetic Aperture Radar (SAR) imagery shows returned signal that clearly distinguish oil from oil-free surface under optimal wind conditions, which makes it the most frequent used remote sensing technique in oil spill detection. Algorithms of automatic oil spill detection has already been developed for different SAR sensors, including RADARSAT and ENVISAT. In this study, we want to apply automatic oil spill detection algorithms on TerraSAR-X data which is previously developed for ASAR data. The applied methodology includes two steps as segmentation and classification. First segmentation algorithms compiled by C# have been applied under a Bayesian framework adopting a multi-level logistic. After segmentation different classification methods such as feature selection, filter, and embedded selection have been applied. As a result the used classifiers for oil spill detection will be compared, and the complete processing chain will be evaluated.

  4. Genome Organization of the SARS-CoV

    Institute of Scientific and Technical Information of China (English)

    Jing Xu; Zizhang Zhang; Wei Wei; Songgang Li; Jun Wang; Jian Wang; Jun Yu; Huanming Yang; Jianfei Hu; Jing Wang; Yujun Han; Yongwu Hu; Jie Wen; Yan Li; Jia Ji; Jia Ye

    2003-01-01

    Annotation of the genome sequence of the SARS-CoV (severe acute respiratory syndrome-associated coronavirus) is indispensable to understand its evolution and pathogenesis. We have performed a full annotation of the SARS-CoV genome sequences by using annotation programs publicly available or developed by ourselves.Totally, 21 open reading frames (ORFs) of genes or putative uncharacterized proteins (PUPs) were predicted. Seven PUPs had not been reported previously, and two of them were predicted to contain transmembrane regions. Eight ORFs partially overlapped with or embedded into those of known genes, revealing that the SARS-CoV genome is a small and compact one with overlapped coding regions.The most striking discovery is that an ORF locates on the minus strand. We have also annotated non-coding regions and identified the transcription regulating sequences (TRS) in the intergenic regions. The analysis of TRS supports the minus strand extending transcription mechanism of coronavirus. The SNP analysis of different isolates reveals that mutations of the sequences do not affect the prediction results of ORFs.

  5. Retrieval of ocean surface wind stress and drag coefficient from spaceborne SAR

    Institute of Scientific and Technical Information of China (English)

    杨劲松; 黄韦艮; 周长宝

    2001-01-01

    A model for retrieval of wind stress and drag coefficient on the sea surface with the data measured by spacebome synthetic aperture radar (SAR) has been developed based on the SAR imaging mechanisms of ocean surface capillary waves and short gravity waves. This model consists of radiometric calibration, wind speed retrieval and wind stress and drag coefficient calculation. A Radarsat SAR image has been used to calculate wind stress and drag coeffi cient. Good results have been achieved.

  6. Adding Precise Wave-Propagation Information and Geodetic Corrections to Standard SAR Products

    OpenAIRE

    Eineder, Michael; Balss, Ulrich; Cong, Xiaoying; Suchandt, Steffen; Gisinger, Christoph; Runge, Hartmut

    2015-01-01

    The inherent geometric accuracy of Synthetic Aperture Radar (SAR) imagery was in the past not fully exploited. It is generally limited by the knowledge of satellite orbit, SAR instrument timing knowledge and stability, different coordinate systems of sensor and object, atmospheric propagation delays (ionosphere and troposphere), solid earth dynamics and calibration procedures and annotation. Indeed, the SAR imaging process shares many features with GNSS systems and during the recent years we ...

  7. Air pollution and case fatality of SARS in the People's Republic of China: an ecologic study

    OpenAIRE

    Yu Shun-Zhang; Wang Hua; Zhao Jinkou; Froines John; Zhang Zuo-Feng; Cui Yan; Detels Roger

    2003-01-01

    Abstract Background Severe acute respiratory syndrome (SARS) has claimed 349 lives with 5,327 probable cases reported in mainland China since November 2002. SARS case fatality has varied across geographical areas, which might be partially explained by air pollution level. Methods Publicly accessible data on SARS morbidity and mortality were utilized in the data analysis. Air pollution was evaluated by air pollution index (API) derived from the concentrations of particulate matter, sulfur diox...

  8. The application of satellite differential SAR interferometry-derived ground displacements in hydrogeology

    OpenAIRE

    Galloway, Devin L.; Hoffmann, Jörn

    2006-01-01

    The application of satellite differential synthetic aperture radar (SAR) interferometry, principally coherent (InSAR) and to a lesser extent, persistent-scatterer (PSI) techniques to hydrogeologic studies has improved capabilities to map, monitor, analyze, and simulate groundwater flow, aquifer-system compaction and land subsidence. A number of investigations over the previous decade show how the spatially detailed images of ground displacements measured with InSAR have advanced hydrogeologic...

  9. An Outbreak of Human Coronavirus OC43 Infection and Serological Cross-reactivity with SARS Coronavirus

    OpenAIRE

    David M Patrick; Martin Petric; Danuta M Skowronski; Roland Guasparini; Timothy F Booth; Mel Krajden; Patrick McGeer; Nathalie Bastien; Larry Gustafson; Janet Dubord; Diane MacDonald; David, Samara T; Leila F Srour; Robert Parker; Anton Andonov

    2006-01-01

    BACKGROUND: In summer 2003, a respiratory outbreak was investigated in British Columbia, during which nucleic acid tests and serology unexpectedly indicated reactivity for severe acute respiratory syndrome coronavirus (SARS-CoV).METHODS: Cases at a care facility were epidemiologically characterized and sequentially investigated for conventional agents of respiratory infection, SARS-CoV and other human CoVs. Serological cross-reactivity between SARS-CoV and human CoV-OC43 (HCoV-OC43) was inves...

  10. Homelessness and the Response to Emerging Infectious Disease Outbreaks: Lessons from SARS

    OpenAIRE

    Leung, Cheryl S.; Ho, Minnie M.; Kiss, Alex; Gundlapalli, Adi V.; Hwang, Stephen W.

    2008-01-01

    During the 2003 severe acute respiratory syndrome (SARS) outbreak in Toronto, the potential introduction of SARS into the homeless population was a serious concern. Although no homeless individual in Toronto contracted SARS, the outbreak highlighted the need to develop an outbreak preparedness plan that accounts for unique issues related to homeless people. We conducted key informant interviews with homeless service providers and public health officials (n = 17) and identified challenges spec...

  11. Draft Genome Sequence of Uncultured SAR324 Bacterium lautmerah10, Binned from a Red Sea Metagenome

    KAUST Repository

    Haroon, Mohamed F.

    2016-02-11

    A draft genome of SAR324 bacterium lautmerah10 was assembled from a metagenome of a surface water sample from the Red Sea, Saudi Arabia. The genome is more complete and has a higher G+C content than that of previously sequenced SAR324 representatives. Its genomic information shows a versatile metabolism that confers an advantage to SAR324, which is reflected in its distribution throughout different depths of the marine water column.

  12. Delta-proteobacterial SAR324 group in hydrothermal plumes on the South Mid-Atlantic Ridge

    OpenAIRE

    Huiluo Cao; Chunming Dong; Salim Bougouffa; Jiangtao Li; Weipeng Zhang; Zongze Shao; Bajic, Vladimir B.; Pei-Yuan Qian

    2016-01-01

    In the dark ocean, the SAR324 group of Delta-proteobacteria has been associated with a chemolithotrophic lifestyle. However, their electron transport chain for energy generation and information system has not yet been well characterized. In the present study, four SAR324 draft genomes were extracted from metagenomes sampled from hydrothermal plumes in the South Mid-Atlantic Ridge. We describe novel electron transport chain components in the SAR324 group, particularly the alternative complex I...

  13. Potent and specific inhibition of SARS-CoV antigen expression by RNA interference

    Institute of Scientific and Technical Information of China (English)

    TAO Peng; ZHANG Jun; TANG Ni; ZHANG Bing-qiang; HE Tong-chuan; HUANG Ai-long

    2005-01-01

    Background Severe acute respiratory syndrome (SARS) is an infectious disease caused by SARS-CoV. There are no effective antiviral drugs for SARS although the epidemic of SARS was controlled. The aim of this study was to develop an RNAi (RNA interference) approach that specifically targeted the N gene sequence of severe acute respiratory syndrome associated coronavirus (SARS-CoV) by synthesizing short hairpin RNA (shRNA) in vivo, and to assess the inhibitory effect of this shRNA on SARS-CoV N antigen expression. Methods The eukaryotic expression plasmid pEGFP-C1-N, containing SARS-CoV N gene, was co-transfected into 293 cells with either the RNAi plasmid pshRNA-N or unrelated control plasmid pshRNA-HBV-C4. At 24, 48 and 72 hours post transfection, the green fluorescence was observed through a fluorescence microscope. The RNA levels of SARS-CoV N were determined by reverse transcription polymerase chain reaction (RT-PCR). The expression of Green Fluorescent Protein (GFP) and protein N were detected using Western blot.Results The vector, pshRNA-N expressing shRNA which targeted the N gene of SARS-CoV, was successfully constructed. The introduction of RNAi plasmid efficiently and specifically inhibited the synthesis of protein N. RT-PCR showed that RNAs of N gene were clearly reduced when the pEGFP-C1-N was cotransfected with pshRNA-N, whereas the control vector did not exhibit inhibitory effect on N gene transcription.Conclusions Our results demonstrate that RNAi mediated silencing of SARS-CoV gene could effectively inhibit expression of SARS-CoV antigen, hence RNAi based strategy should be further explored as a more efficacious antiviral therapy of SARS-CoV infection.

  14. Alcohol Abuse/Dependence Symptoms Among Hospital Employees Exposed to a SARS Outbreak

    OpenAIRE

    Wu, Ping; Liu, Xinhua; Fang, Yunyun; Fan, Bin; Fuller, Cordelia J.; Guan, Zhiqiang; Yao, Zhongling; Kong, Junhui; Lu, Jin; Litvak, Iva J.

    2008-01-01

    Aims: The aim of this study was to examine alcohol abuse/dependence symptoms among hospital employees exposed to a severe acute respiratory syndrome (SARS) outbreak, and the relationship between types of exposure to the SARS outbreak and subsequent alcohol abuse/dependence symptoms. Methods: A survey was conducted among 549 randomly selected hospital employees in Beijing, China, concerning the psychological impact of the 2003 SARS outbreak. Subjects were assessed on sociodemographic factors a...

  15. A SAR image-based tool for prompt and effective earthquake response

    OpenAIRE

    Guida, R.; Brett, PTB

    2011-01-01

    Recently, a new concept for detection of damaged infrastructure after earthquakes has been introduced, based on analysis of double reflection lines in SAR images. This paper describes the development of a processing step for extraction of double-reflection lines, and its implementation. In particular, an unsupervised bright line detector working on the ratio of pre- and post-event single look complex SAR data is introduced, and is demonstrated using COSMO-SkyMed SAR data from the 2009 L'Aquil...

  16. Quality evaluation of DInSAR results from the phase statistical analysis

    OpenAIRE

    Centolanza, Giuseppe

    2015-01-01

    The Earth is continuously monitored by sensors capable of providing diversified information about several phenomena. In particular Synthetic Aperture Radar (SAR) is able to observe the Earth in all-day and all-weather conditions. Differential SAR Interferometry (DInSAR) regards a set of techniques able to measure displacement of the terrain. In the last decades these techniques have become very powerful geodetic tools for land deformation monitoring and have gained a prominent role in several...

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

    OpenAIRE

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

    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 ...

  18. SYNTHETIC APERTURE RADAR (SAR) BASED CLASSIFIERS FOR LAND APPLICATIONS IN GERMANY

    OpenAIRE

    Suresh, G.; Gehrke, R.; T. Wiatr; Hovenbitzer, M.

    2016-01-01

    Land cover information is essential for urban planning and for land cover change monitoring. This paper presents an overview of the work conducted at the Federal Agency for Cartography and Geodesy (BKG) with respect to Synthetic Aperture Radar (SAR) based land cover classification. Two land cover classification approaches using SAR images are reported in this paper. The first method involves a rule-based classification using only SAR backscatter intensity while the other method involves super...

  19. SAR Cross-Ambiguities in SAOCOM-CS Large Baseline Bistatic Configuration

    OpenAIRE

    Bordoni, Federica; Rodriguez-Cassola, Marc; Younis, Marwan; Prats-Iraola, Pau; Lopez-dekker, Paco; Krieger, Gerhard

    2016-01-01

    The evaluation of the ambiguous signal level, the Ambiguity-to-Signal Ratio (ASR), plays a key role in the Synthetic Aperture Radar (SAR) design and performance prediction. In conventional SAR acquisition scenarios, the computation of the ASR is based on the evaluation of the range and azimuth ambiguous contributes. Though appealing for its simplicity, this approach could be inaccurate in case of complex SAR acquisition geometries. In this paper we focus on the ASR performance of the SAOCOM-...

  20. Demonstration of Single-Pass Millimeterwave SAR Tomography for Forest Volumes

    OpenAIRE

    Schmitt, Michael; Zhu, Xiao Xiang

    2016-01-01

    In this letter, for the first time, the potential of millimeterwave synthetic aperture radar (SAR) is investigated with respect to a tomographic analysis of forest volumes. Exploiting both parametric and nonparametric SAR tomography (TomoSAR) methods designed for both discrete and continuous reflectivity profiles, it is shown that even Ka-band signals with a wavelength of only 8.55 mm can penetrate the tree canopy to a certain extent and allow a separation of ground and tree crowns. First exp...

  1. Landslide Mapping in Vegetated Areas Using Change Detection Based on Optical and Polarimetric SAR Data

    OpenAIRE

    Simon Plank; André Twele; Sandro Martinis

    2016-01-01

    Mapping of landslides, quickly providing information about the extent of the affected area and type and grade of damage, is crucial to enable fast crisis response, i.e., to support rescue and humanitarian operations. Most synthetic aperture radar (SAR) data-based landslide detection approaches reported in the literature use change detection techniques, requiring very high resolution (VHR) SAR imagery acquired shortly before the landslide event, which is commonly not available. Modern VHR SAR ...

  2. Attempt of alpine glacier flow modeling based on correlation measurements of high resolution SAR images

    OpenAIRE

    Yan, Yajing; Ferro-Famil, Laurent; Gay, Michel; Fallourd, Renaud; Trouvé, Emmanuel; Vernier, Flavien

    2013-01-01

    International audience In this paper, an attempt of Alpine glacier flow modeling is performed based on a series of high resolution TerraSAR-X SAR images and a Digital Elevation Model. First, a glacier flow model is established according to the fluid mechanics theory in a simplified framework. Second, the displacement field over the glacier obtained from the sub-pixel image correlation of a series of TerraSAR-X SAR images is used to refine the model obtained previously. The comparison betwe...

  3. Spaceborne Synthetic Aperture Radar (SAR)Systems: State of the Art and Future Developments

    OpenAIRE

    Moreira, Alberto; Krieger, Gerhard

    2003-01-01

    This paper first summarizes the state of the art in spaceborne SAR systems and applications.The second part of this paper gives an overview of new concepts,techniques and technologies for future SAR systems,allowing an increase of flexibility in the SAR operation mode as well as a reduction in the overall system costs.Several innovative concepts and technologies as bi- and multi-static configurations,parasitic SAR,sparse aperture systems and digital beamforming will play an important role for...

  4. Offshore wind resource mapping for Europe by Synthetic Aperture Radar (SAR) satellite data

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete

    2015-01-01

    satellite remote sensing observations and atmospheric modelling. The satellite data include Synthetic Aperture Radar (SAR) from the European Space Agency from Envisat and the Copernicus mission Sentinel-1. SAR has the advantage of high spatial resolution such that we can cover near-coastal areas where many...... wind farms are planned. In the Danish RUNE project near-shore offshore winds are investigate from SAR, atmospheric modelling and ground-based remote sensing lidar. In the European Space Agency project ResGrow SAR wind resource maps at various locations in the European Seas are used to estimate the wind...

  5. SAR Imagery Simulation of Ship Based on Electromagnetic Calculations and Sea Clutter Modelling for Classification Applications

    International Nuclear Information System (INIS)

    Ship detection and classification with space-borne SAR has many potential applications within the maritime surveillance, fishery activity management, monitoring ship traffic, and military security. While ship detection techniques with SAR imagery are well established, ship classification is still an open issue. One of the main reasons may be ascribed to the difficulties on acquiring the required quantities of real data of vessels under different observation and environmental conditions with precise ground truth. Therefore, simulation of SAR images with high scenario flexibility and reasonable computation costs is compulsory for ship classification algorithms development. However, the simulation of SAR imagery of ship over sea surface is challenging. Though great efforts have been devoted to tackle this difficult problem, it is far from being conquered. This paper proposes a novel scheme for SAR imagery simulation of ship over sea surface. The simulation is implemented based on high frequency electromagnetic calculations methods of PO, MEC, PTD and GO. SAR imagery of sea clutter is modelled by the representative K-distribution clutter model. Then, the simulated SAR imagery of ship can be produced by inserting the simulated SAR imagery chips of ship into the SAR imagery of sea clutter. The proposed scheme has been validated with canonical and complex ship targets over a typical sea scene

  6. ALGORITHM OF SAR SATELLITE ATTITUDE MEASUREMENT USING GPS AIDED BY KINEMATIC VECTOR

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, in order to improve the accuracy of the Synthetic Aperture Radar (SAR)satellite attitude using Global Positioning System (GPS) wide-band carrier phase, the SAR satellite attitude kinematic vector and Kalman filter are introduced. Introducing the state variable function of GPS attitude determination algorithm in SAR satellite by means of kinematic vector and describing the observation function by the GPS wide-band carrier phase, the paper uses the Kalman filter algorithm to obtian the attitude variables of SAR satellite. Compared the simulation results of Kalman filter algorithm with the least square algorithm and explicit solution, it is indicated that the Kalman filter algorithm is the best.

  7. Structural Modeling and Analysis on Dynamic Characteristics of Antenna Pedestal in Airborne SAR

    Directory of Open Access Journals (Sweden)

    He Li-ping

    2012-06-01

    Full Text Available Finite element modeling and structural dynamic characteristics of antenna pedestal in airborne SAR were studied in this paper. The Finite element model of antenna pedestal in airborne SAR was set up on the basis of structural dynamic theory, then, the key technologies of dynamic simulation were pointed out, and the modal analysis and transient analysis were carried out. Simulation results show that the dynamic characteristics of antenna pedestal in airborne SAR can meet the requirements of servo bandwidth and structural strength. The fast finite element modeling and simulation method proposed in this paper are of great significance to the weight reducing design of antenna pedestal in airborne SAR.

  8. Putative hAPN receptor binding sites in SARS_CoV spike protein

    Institute of Scientific and Technical Information of China (English)

    YUXiao-Jing; LUOCheng; LinJian-Cheng; HAOPei; HEYou-Yu; GUOZong-Ming; QINLei; SUJiong; LIUBo-Shu; HUANGYin; NANPeng; LIChuan-Song; XIONGBin; LUOXiao-Min; ZHAOGuo-Ping; PEIGang; CHENKai-Xian; SHENXu; SHENJian-Hua; ZOUJian-Ping; HEWei-Zhong; SHITie-Liu; ZHONGYang; JIANGHua-Liang; LIYi-Xue

    2003-01-01

    AIM:To obtain the information of ligand-receptor binding between thd S protein of SARS_CoV and CD13, identify the possible interacting domains or motifs related to binding sites, and provide clues for studying the functions of SARS proteins and designing anti-SARS drugs and vaccines. METHODS: On the basis of comparative genomics, the homology search, phylogenetic analyses, and multi-sequence alignment were used to predict CD13 related interacting domains and binding sites sites in the S protein of SARS_CoV. Molecular modeling and docking simulation methods were employed to address the interaction feature between CD13 and S protein of SARS_CoV in validating the bioinformatics predictions. RESULTS:Possible binding sites in the SARS_CoV S protein to CD13 have been mapped out by using bioinformatics analysis tools. The binding for one protein-protein interaction pair (D757-R761 motif of the SARS_CoV S protein to P585-A653 domain of CD13) has been simulated by molecular modeling and docking simulation methods. CONCLUSION:CD13 may be a possible receptor of the SARS_CoV S protein which may be associated with the SARS infection. This study also provides a possible strategy for mapping the possible binding receptors of the proteins in a genome.

  9. Tracking the Evolution of the SARS Coronavirus Using High-Throughput, High-Density Resequencing Arrays

    OpenAIRE

    Wong, Christopher W.; Albert, Thomas J.; Vega, Vinsensius B.; Norton, Jason E.; Cutler, David J; Richmond, Todd A.; Stanton, Lawrence W; Liu, Edison T; Lance D. Miller

    2004-01-01

    Mutations in the SARS-Coronavirus (SARS-CoV) can alter its clinical presentation, and the study of its mutation patterns in human populations can facilitate contact tracing. Here, we describe the development and validation of an oligonucleotide resequencing array for interrogating the entire 30-kb SARS-CoV genome in a rapid, cost-effective fashion. Using this platform, we sequenced SARS-CoV genomes from Vero cell culture isolates of 12 patients and directly from four patient tissues. The sequ...

  10. Development of a High Resolution Airborne Millimeter Wave FM-CW SAR

    OpenAIRE

    Meta, A; Wit, J.J.M. de; Hoogeboom, P.

    2004-01-01

    The combination of compact FM-CW radar technology and high resolution SAR processing techniques should pave the way for the development of a small, lightweight and cost effective imaging radar. In the field of airborne earth observation, SAR is however a novel application for FM-CW radars. At IRCTR a project was started to investigate the practical feasibility of FM-CW SAR. Within the framework of this project a fully operational airborne FM-CW SAR demonstrator system has been developed and t...

  11. SAR variation study from 300 to 5000 MHz for 15 voxel models including different postures

    International Nuclear Information System (INIS)

    An extensive study on specific absorption rate (SAR) covering 720 simulations and 15 voxel models (18-105 kg) has been performed by applying the parallel finite-difference time-domain method. High-resolution whole-body models have been irradiated with plane waves from 300 MHz to 5 GHz by applying various incoming directions and polarizations. Detailed results of whole-body SAR and peak 10 g SAR are reported, and SAR variation in the dB scale is examined. For an adult, the effect of incoming direction on whole-body SAR is larger in the GHz range than at around 300-450 MHz, and the effect is stronger with vertical polarization. For a child (height ∼1.2 m), the effect of incoming direction is similar as for an adult, except at 300 MHz for horizontal polarization. The effect of the phantom (18-105 kg) on whole-body SAR is larger at around 2-5 GHz and at vertical 300 MHz (proximity of whole-body resonance for the child) than at around horizontal 300-900 MHz. Body posture has little effect on whole-body SAR in the GHz range, but at around 300-450 MHz, one may even expect a 2 dB rise in whole-body SAR if posture is changed from the standing position. Posture affects peak 10 g SAR much more than whole-body SAR. The polarization of the incident electric field may have an effect of several dB on whole-body SAR. Between 2 and 5 GHz for adults, whole-body SAR is higher for horizontal than for vertical polarization, if the incoming direction is in the azimuth plane. In the GHz range, horizontal polarization gives higher whole-body SAR, especially for irradiation from the lateral direction. A comparison between homogeneous and heterogeneous models was done. A homogenized model underestimates whole-body SAR, especially at ∼2 GHz. The basic restriction of whole-body SAR, set by ICNIRP, is exceeded in the smallest models (∼20 kg) at the reference level of exposure, but also some adult phantoms are close to the limit. The peak 10 g SAR limits were never exceeded in the studied

  12. Measurement of Sinkhole Formation and Progression with InSAR

    Science.gov (United States)

    Jones, C. E.; Blom, R. G.

    2013-12-01

    The Bayou Corne Sinkhole initially formed in August 2012 from sidewall collapse of a brine cavern within the Napoleonville Salt Dome in southeastern Louisiana. The sinkhole, initially ~1 hectare in size, has expanded to ~10 hectare surface coverage by July 2013, as material continued to fill the subterranean void. Here we show that synthetic aperture radar (SAR) interferometry (InSAR) could have reliably forecast the formation and location of the Bayou Corne Sinkhole at least a month in advance from the large precursory surface deformation that occurred in the area where the sinkhole later formed. The Mississippi delta region has been imaged since 2009 using the NASA Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), and radar data over the Napoleonville Salt Dome had been acquired on 2 July 2012, only a month before the sinkhole developed. Using radar interferometry, we show significant surface deformation of up to 250 mm occurred between 23 June 2011, and 2 July 2012, in an extended area encompassing the sinkhole site. The InSAR results show no measurable deformation prior to 23 June 2011. The measured precursory deformation pattern is consistent with compressive loading at the surface due to removal of support caused by a vertically oriented subsurface fracture. The measured strains relate directly to subsurface geology, salt rock properties, and internal stresses caused by the salt dome sidewall collapse. Measurements made with UAVSAR since the sinkhole formation, between August 2012 and July 2013, show progression of the surface deformation well beyond the limited extent of the sinkhole itself, with growth of the sinkhole following the direction of maximum surface deformation. These results show that even in radar-challenging environments such as the swamplands of Bayou Corne, L-band InSAR can be used to study the underlying geophysics of sinkhole formation and, furthermore, that InSAR data collected operationally for hazard monitoring could

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

    Science.gov (United States)

    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.

  14. Improved Oceanographic Measurements with CryoSat SAR Altimetry

    Science.gov (United States)

    Cotton, David; Benveniste, Jérôme; Cipollini, Paolo; Andersen, Ole; Cancet, Mathilde; Ambrózio, Américo; Restano, Marco; Nilo Garcia, Pablo; Martin, Francisco

    2016-07-01

    The ESA CryoSat mission is the first space mission to carry a radar altimeter that can operate in Synthetic Aperture Radar "SAR" (or delay-Doppler) and interferometric SAR (SARin) modes. Studies on CryoSat data have analysed and confirmed the improved ocean measuring capability offered by SAR mode altimetry, through increased resolution and precision in sea surface height and wave height measurements, and have also added significantly to our understanding of the issues around the processing and interpretation of SAR altimeter echoes. We present work in four themes, building on work initiated in the CryoSat Plus for Oceans project (CP4O), each investigating different aspects of the opportunities offered by this new technology. The first two studies address the coastal zone, a critical region for providing a link between open-ocean and shelf sea measurements with those from coastal in-situ measurements, in particular tide gauges. Although much has been achieved in recent years through the Coastal Altimetry community, (http://www.coastalt.eu/community) there is a limit to the capabilities of pulse-limited altimetry, which often leaves an un-measured "white strip" right at the coastline. Firstly, a thorough analysis was made of the performance of "SAR" altimeter data (delay-Doppler processed) in the coastal zone. This quantified the performance, confirming the significant improvement over "conventional" pulse-limited altimetry. In the second study a processing scheme was developed with CryoSat SARin mode data to enable the retrieval of valid oceanographic measurements in coastal areas with complex topography. Thanks to further development of the algorithms, a new approach was achieved that can also be applied to SAR and conventional altimetry data (e.g., Sentinel-3, Jason series, Envisat). The third part of the project developed and evaluated improvements to the SAMOSA altimeter re-tracker that is implemented in the Sentinel-3 processing chain. The modifications to the

  15. 靶向SARS-CoV spike中和抗体的检测%Targeting SARS-CoV spike neutralizing antibody test

    Institute of Scientific and Technical Information of China (English)

    马萍; 杨宁; 郎建设; 蒋澄宇

    2012-01-01

    目的 建立靶向SARS-CoV spike中和抗体的检测模型.方法 构建优化的全基因SARS-CoV spike质粒免疫小鼠产生S1190抗血清,与合成的结合受体ACE2的S318-510蛋白进行作用,通过荧光显微镜观察对SARS假病毒感染抑制作用的变化以确证中和抗体的高效性.结果 SARS-CoV spike质粒诱导产生的S蛋白全长抗血清不但可以有效中和SARS假病毒进入HEK293E/ACE2-Myc细胞,S318-510蛋白的预处理可以降低抗血清对SARS假病毒的进入抑制效应.结论 受体结合部(RBD)的S318-510蛋白靶向SARS-CoV spike中和抗体的检测模型得到有效的验证.可以作为直观迅速判断中和抗体是否高效的模型推广至不具备P3级别的实验室.%Objective To establish a targeting SARS-CoV spike neutralizing antibody test model. Methods Construction of optimal whole SARS-CoV spike gene plasmid to induce mouse neutralizing antibody. Pretreatment with S318-510 protein targeting ACE2 to observe the inhibition change of SARS-CoV S pseudoviruses infection process via fluorescence microscope. Results _ SARS-CoV SI 190 Abs prevented SARS-CoV pseudovirus entry into HEK293E/ACE2-Myc cells and pretreatment with S318-510 inhibited neutralization of SARS-S entry antiserum. Conclusions This test model confirmation of SARS-CoV RBD targeting SARS-CoV spike neutralizing antibody may function as a test model of lethal viruses in laboratory not equiped as biosafety level 3.

  16. Forest height estimation in a tropical forest context from PolInSAR measurements: Illustration from the TropiSAR campaign in French Guyana

    Science.gov (United States)

    Dubois-Fernandez, P.; Le Toan, T.; Chave, J.; Blanc, L.; Daniel, S.; Davidson, M.

    2010-12-01

    The BIOMASS mission was retained in January 2009 as one of the three candidates for the next Earth Explorer Core mission to go to phase A. BIOMASS main objective is to provide information on the carbon sinks and sources in the forests globally, which will be of essential value for climate modelling and policy adaptation, e.g. REDD. Up to now, biomass retrieval algorithms have been developed and validated for the range of biomass up to 300 t/ha. The methods are based on combining SAR intensity and SAR Polarimetric interferometry (PolInSAR) which provide respectively estimates of biomass and canopy height. The remaining questions concern the overall performance of the retrieval algorithms in tropical forests characterized by high biomass density (> 300 t/ha) and complex structure. The TropiSAR experiment in French Guyana was proposed to provide feedbacks on the performances of a P-band SAR to measure biomass and canopy height of a tropical forest with higher biomass density. Characterising tropical forests is essential as it represents a large component of the terrestrial carbon pool and the carbon sources. Specifically, TropiSAR was designed to provide measurements of temporal coherence at P-band over tropical forests for time intervals compatible with space-borne missions (typically 20-30 days), to assess performances of methods transforming P-Band SAR intensity and interferometric measurements into forest biomass and forest height. The SAR system is the ONERA airborne system SETHI that flew in French Guyana in August 2009. This paper presents the first results from this analysis. The temporal coherence at P-band over tropical forests is observed to remain high even after 22 days, a time interval period compatible with typical SAR orbit cycle. The vegetation height map estimated from Polarimetric interferometry is shown to be in good agreement with Lidar measured heights and the in-situ measurements in the study area. The PolInSAR derived height captures the main

  17. Hydrodynamics of the Groundwater-Fed Sian Ka'an Wetlands, Mexico, From InSAR and SAR Data

    Science.gov (United States)

    Gondwe, B. R.; Hong, S.; Wdowinski, S.; Bauer-Gottwein, P.

    2008-12-01

    The 5300 km2 pristine Sian Ka'an wetland in Mexico is fed entirely by groundwater from the karst aquifer of the Yucatan Peninsula. The area is undeveloped and hence difficult to access. The inflow through underground rivers and karst structures is hard to observe resulting in difficulties to understand, quantify and predict the wetland dynamics. Remotely sensed Interferometric Synthetic Aperture Radar (InSAR) and Synthetic Aperture Radar (SAR) data offer new opportunities to get hydrodynamic information, which is useful for wetland management. InSAR data produces temporal phase-changes of the backscattered radar signal, which can be related to the water level changes in vegetated wetlands. SAR data reveals information of surface properties such as the degree of flooding through the amplitude of the backscattered signal. We used RADARSAT-1 InSAR and SAR data to form 36 interferograms and 13 flooding maps with 24 to 48 day intervals covering the time span of October 2006 to March 2008. The dataset has a high spatial resolution of ca. 20 to 60 m. Sian Ka'an consists of a mosaic of freshwater sloughs, canals, floodplains and brackish tidally-influenced areas. Throughout most of the year, water level changes in the wetland are almost uniform, resulting in a very low fringe signal in the InSAR-observations. However, during periods of maximum water levels in the wetland, steeper gradients of water level changes are observed in the wetland's sloughs, more than in the surrounding floodplains. The data reveal that two sloughs and a canal-shaped feature are main source areas feeding water into the wetland. The maximum relative water level changes observed in the wetland are 48 cm. Tide-induced water level changes appear to occur in 3 separate areas, with a maximum relative change of 24 cm, corresponding well with tidal predictions. The interferograms also reveal information about surface water flow directions and local-scale flow divides in the wetland, which are important

  18. Factors contributing to the biofilm-deficient phenotype of Staphylococcus aureus sarA mutants.

    Directory of Open Access Journals (Sweden)

    Laura H Tsang

    Full Text Available Mutation of sarA in Staphylococcus aureus results in a reduced capacity to form a biofilm, but the mechanistic basis for this remains unknown. Previous transcriptional profiling experiments identified a number of genes that are differentially expressed both in a biofilm and in a sarA mutant. This included genes involved in acid tolerance and the production of nucleolytic and proteolytic exoenzymes. Based on this we generated mutations in alsSD, nuc and sspA in the S. aureus clinical isolate UAMS-1 and its isogenic sarA mutant and assessed the impact on biofilm formation. Because expression of alsSD was increased in a biofilm but decreased in a sarA mutant, we also generated a plasmid construct that allowed expression of alsSD in a sarA mutant. Mutation of alsSD limited biofilm formation, but not to the degree observed with the corresponding sarA mutant, and restoration of alsSD expression did not restore the ability to form a biofilm. In contrast, concomitant mutation of sarA and nuc significantly enhanced biofilm formation by comparison to the sarA mutant. Although mutation of sspA had no significant impact on the ability of a sarA mutant to form a biofilm, a combination of protease inhibitors (E-64, 1-10-phenanthroline, and dichloroisocoumarin that was shown to inhibit the production of multiple extracellular proteases without inhibiting growth was also shown to enhance the ability of a sarA mutant to form a biofilm. This effect was evident only when all three inhibitors were used concurrently. This suggests that the reduced capacity of a sarA mutant to form a biofilm involves extracellular proteases of all three classes (serine, cysteine and metalloproteases. Inclusion of protease inhibitors also enhanced biofilm formation in a sarA/nuc mutant, with the combined effect of mutating nuc and adding protease inhibitors resulting in a level of biofilm formation with the sarA mutant that approached that of the UAMS-1 parent strain. These results

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

    International Nuclear Information System (INIS)

    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 the 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

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

    Energy Technology Data Exchange (ETDEWEB)

    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 the 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.