Science.gov

Sample records for mit dem opal-detektor

  1. Astronomie mit dem Personal Computer.

    NASA Astrophysics Data System (ADS)

    Montenbruck, O.; Pfleger, T.

    Dritte, völlig neubearbeitete Auflage, Programmiersprache C++ (2. Auflage 1994, Abstr. 61.003.023). Die CD-ROM enthält neben den Quelltexten auch die ausführbaren Programme für Windows 95/98/NT und Linux. Contents: 1. Einführung. 2. Koordinatensysteme. 3. Auf- und Untergangsrechnung. 4. Kometenbahnen. 5. Störungsrechnung. 6. Planetenbahnen. 7. Physische Planetenephemeriden. 8. Die Mondbahn. 9. Sonnenfinsternisse. 10. Sternbedeckungen. 11. Bahnbestimmung. 12. Astrometrie.

  2. Entwicklung und lmplementierung von Analysemethoden zum Erfassen vonGeschwindigkeitsfeldem mit dem PIV Verfahren (Development and Implementation of Analytical Methods for Detecting Velocity Fields using PIV- Method)

    DTIC Science & Technology

    2016-04-26

    Particle-Image-Velocimetry 1 064nm beam dump 532nm output / Dielectric polarizer Doubling crystal Laser mirrors and plates Output couple Nd:YAG Rod...zuriickgesetzt. Der Anwender befindet sic :1 wieder an dem Funkt im Programm, nachdem er die Bildpaare eingelesen hatte. 5.2.3. Auswertung der Daten und

  3. Auf der Suche nach dem Codierungs-Gral für genetische Algorithmen

    NASA Astrophysics Data System (ADS)

    Weicker, Karsten

    Die umstrittene Frage nach dem "wichtigsten" Operator im genetischen Algorithmus - Mutation oder Crossover - hängt eng zusammen mit der Frage nach der richtigen binären Codierung. Gray- und standardbinärer Code bringen unterschiedliche Vor- und Nachteile in einen genetischen Algorithmus ein. Diese Arbeit beschäftigt sich mit der Suche nach einer Codierung, welche die Vorteile beider Codes vereinbart, und berichtet von einem Teilerfolg für mit 4 Bits encodierten Zahlen.

  4. Unfälle mit motorisierten Zweirädern

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Der Fahrer eines Pkw Opel Astra überquerte mit seinem Pkw von einer untergeordneten Einmündung kommend eine außerörtliche Bundesstraße in gerade Richtung. Dabei kam es zur Kollision mit einem sich von rechts vorfahrtsberechtigt annähernden Krad Suzuki RGV250. Der Anprall des Krades erfolgte mit dem Heck an die rechte Pkw-Flanke zwischen vorderem Radausschnitt und Fahrzeugecke. Der Krad-Fahrer, welcher sofort tot war und das Zweirad verklemmten sich am Pkw und verblieben relativ zu selbigem annähernd in Kollisionsstellung.

  5. MIT: Shaping the Future.

    ERIC Educational Resources Information Center

    Manning, Kenneth R., Ed.

    This book provides 16 essays by faculty and staff of the Massachusetts Institute of Technology (MIT) concerning what MIT is like today and offering a guide to its possible future. Emphasis is placed on local, national, and global issues, providing a current sampling of the state of concerns and opinions around MIT. Topics include the question of…

  6. MIT: Shaping the Future.

    ERIC Educational Resources Information Center

    Manning, Kenneth R., Ed.

    This book provides 16 essays by faculty and staff of the Massachusetts Institute of Technology (MIT) concerning what MIT is like today and offering a guide to its possible future. Emphasis is placed on local, national, and global issues, providing a current sampling of the state of concerns and opinions around MIT. Topics include the question of…

  7. Neutronenforschung Holographie mit Neutronen

    NASA Astrophysics Data System (ADS)

    Krexner, Gerhard

    2003-01-01

    Jeder kennt sie, die räumlich wirkenden Hologramme, die es seit dreißig Jahren etwa zu kaufen gibt. Sie werden mit sichtbarem Laserlicht erstellt. Grundsätzlich spricht nichts dagegen, Hologramme auch mit Materiewellen anzufertigen. Einer internationalen Forschergruppe gelang kürzlich am Institut Laue-Langevin (ILL) in Grenoble erstmals die holographische Abbildung eines Atomgitters mit Neutronen [1].

  8. Nagelbefall kann bei Patienten mit Psoriasis auf eine Enthesiopathie hinweisen.

    PubMed

    Castellanos-González, Maria; Joven, Beatriz Esther; Sánchez, Julio; Andrés-Esteban, Eva María; Vanaclocha-Sebastián, Francisco; Romero, Pablo Ortiz; Díaz, Raquel Rivera

    2016-11-01

    Obwohl subklinische Enthesiopathie ein gut etabliertes diagnostisches Merkmal der Psoriasisarthritis (PsA) ist, wird sie häufig übersehen, da viele Patienten asymptomatisch sind. Gäbe es klinische Hinweise auf das Vorliegen einer Enthesiopathie, würde dies den Klinikern die Möglichkeit eröffnen, eine PsA frühzeitig zu diagnostizieren. Es wurde eine monozentrische prospektive Studie mit insgesamt 90 Psoriasis-Patienten durchgeführt, um mittels Ultraschall das Vorliegen von Enthesenanomalien zu untersuchen und eine Korrelation mit dem Befall der Nägel festzustellen. Enthesenanomalien wurden bei 23 Patienten (25,5 %) gefunden, von denen 19 (82,6 %) Nagelbefall aufwiesen. Bei 4 Patienten waren die Nägel nicht betroffen. Enthesiopathie lag bei 31,1 % (19/61) der Patienten mit Onychopathie vor, von den Patienten ohne Nagelbefall litten nur 13,8 % (4/29) an Enthesiopathie (p = 0,07). Zwischen dem Target-NAPSI-Score und dem Vorliegen einer Enthesiopathie bestand eine signifikante Korrelation. Eine signifikante Korrelation bestand darüber hinaus auch zwischen dem Vorliegen einer Enthesiopathie und der Anzahl der betroffenen Nägel (p = 0,035). Klinische Belege für eine Onychopathie können der Schlüssel für die frühe Diagnose einer Enthesiopathie bei Psoriasis-Patienten sein. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  9. Sterblichkeit: der paradoxe Kunstgriff des Lebens - Eine Betrachtung vor dem Hintergrund der modernen Biologie

    NASA Astrophysics Data System (ADS)

    Verbeek, Bernhard

    Leben gibt es auf der Erde seit fast 4 Mio. Jahren, trotz allen Katastrophen. Die Idee des Lebens scheint unsterblich. Der Tod aber offenbar auch. Jedes Lebewesen ist davon bedroht, ja für Menschen und andere "höhere“ Lebewesen ist er im Lebensprogramm eingebaut - todsicher. Diese Tatsache ist alles andere als selbstverständlich. Ist sie überhaupt kompatibel mit dem Prinzip der Evolution, nach dem der am besten Angepasste überlebt?

  10. Entwicklungsperspektiven von Social Software und dem Web 2.0

    NASA Astrophysics Data System (ADS)

    Raabe, Alexander

    Der Artikel beschäftigt sich zunächst mit dem derzeitigen und zukünftigen Einsatz von Social Software in Unternehmen. Nach dem großen Erfolg von Social Software im Web beginnen viele Unternehmen eigene Social Software-Initiativen zu entwickeln. Der Artikel zeigt die derzeit wahrgenommenen Einsatzmöglichkeiten von Social Software im Unternehmen auf, erörtert Erfolgsfaktoren für die Einführung und präsentiert mögliche Wege für die Zukunft. Nach der Diskussion des Spezialfalles Social Software in Unternehmen werden anschließend die globalen Trends und Zukunftsperspektiven des Web 2.0 in ihren technischen, wirtschaftlichen und sozialen Dimensionen dargestellt. Wie aus den besprochenen Haupttrends hervorgeht, wird die Masse an digital im Web verfügbaren Informationen stetig weiterwachsen. So stellt sich die Frage, wie es in Zukunft möglich sein wird, die Qualität der Informationssuche und der Wissensgenerierung zu verbessern. Mit dem Einsatz von semantischen Technologien im Web wird hier eine revolutionäre Möglichkeit geboten, Informationen zu filtern und intelligente, gewissermaßen verstehende" Anwendungen zu entwerfen. Auf dem Weg zu einem intelligenten Web werden sich das Semantic Web und Social Software annähern: Anwendungen wie Semantic Wikis, Semantic Weblogs, lightweight Semantic Web-Sprachen wie Microformats oder auch kommerzielle Angebote wie Freebase von Metaweb werden die ersten Vorzeichen einer dritten Generation des Webs sein.

  11. Performance Assessment of the Final TanDEM-X DEM

    NASA Astrophysics Data System (ADS)

    Boer, Johannes; Gonzalez, Carolina; Wecklich, Chrostopher; Brautigam, Benjamin; Schulze, Daniel; Bachmann, Markus; Zink, Manfred

    2016-08-01

    The TanDEM-X system is an innovative radar mission, which is comprised of two formation flying satellites, with the primary goal of generating a global Digital Elevation Model (DEM) of unprecedented accuracy. TanDEM-X, being a large single-pass radar interferometer, achieves this accuracy through a flexible baseline selection enabling the acquisition of highly accurate cross-track interferograms that are not impacted by temporal decorrelation or atmospheric disturbances. At least two global coverages (at least four in the case of difficult terrain) are combined into a homogenous global DEM mosaic consisting of 1° by 1° geocells. With the DEM data production of the Earths continents almost completed, apart from Antarctica, this paper provides a quality summary of the currently available part of the TanDEM-X global DEM with respect to the DEM absolute and relative height accuracy as well as to void density.

  12. Hinderniserkennung und -verfolgung mit einer PMD-kamera im automobil

    NASA Astrophysics Data System (ADS)

    Schamm, Thomas; Vacek, Stefan; Natroshvilli, Koba; Marius Zöllner, J.; Dillmann, Rüdiger

    Die Detektion von Hindernissen vor dem Automobil ist eine Hauptanforderung an moderne Fahrerassistenzsysteme (FAS). In dieser Arbeit wird ein System vorgestellt, das mit Hilfe einer PMDKamera (Photomischdetektor) Hindernisse auf der Fahrspur erkennt und deren relevante Parameter bestimmt. Durch die PMD-Kamera werden zunächst 3D-Tiefenbilder der Fahrzeugumwelt generiert. Nach einem initialen Filterprozess werden im Tiefenbild mit Hilfe eines Bereichswachstumsverfahrens Hindernisse gesucht. Zur Stabilisierung des Verfahrens und zur Parameterberechnung wird ein Kaiman Filter eingesetzt. Das Ergebnis ist eine Liste aller Hindernisse im Fahrbereich des Automobils.

  13. ASTER DEM performance

    USGS Publications Warehouse

    Fujisada, H.; Bailey, G.B.; Kelly, Glen G.; Hara, S.; Abrams, M.J.

    2005-01-01

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument onboard the National Aeronautics and Space Administration's Terra spacecraft has an along-track stereoscopic capability using its a near-infrared spectral band to acquire the stereo data. ASTER has two telescopes, one for nadir-viewing and another for backward-viewing, with a base-to-height ratio of 0.6. The spatial resolution is 15 m in the horizontal plane. Parameters such as the line-of-sight vectors and the pointing axis were adjusted during the initial operation period to generate Level-1 data products with a high-quality stereo system performance. The evaluation of the digital elevation model (DEM) data was carried out both by Japanese and U.S. science teams separately using different DEM generation software and reference databases. The vertical accuracy of the DEM data generated from the Level-1A data is 20 m with 95% confidence without ground control point (GCP) correction for individual scenes. Geolocation accuracy that is important for the DEM datasets is better than 50 m. This appears to be limited by the spacecraft position accuracy. In addition, a slight increase in accuracy is observed by using GCPs to generate the stereo data.

  14. Zusatz- und Weiterqualifikation nach dem Studium

    NASA Astrophysics Data System (ADS)

    Domnick, Ivonne

    Ist der Bachelor geschafft, stellt sich die Frage nach einer Weiterqualifizierung. Neben einem Einstieg ins Berufsleben kann auch ein Masterstudium eventuell weitere entscheidende Bonuspunkte für den Lebenslauf bringen. Mit Zusatzqualifikationen aus fachfremden Bereichen wie Betriebswirtschaft oder Marketing ist es für Naturwissenschaftler leichter, den Einstieg ins Berufsleben zu schaffen. Viele Arbeitgeber sehen gerade bei Naturwissenschaftlern eine Promotion gerne. Hier sollte genau abgewogen werden, ob sie innerhalb einer bestimmten Zeitspanne zu schaffen ist. Auch nach einem Einstieg in den Job lässt sich der Doktortitel unter Umständen noch nachholen. Ebenso ist eine Weiterbildung neben dem Beruf in Teilzeit oder in einem Fernkurs möglich. Zusätzlich gibt es viele mehrwöchige oder mehrmonatige Kurse privater Anbieter, in denen man BWL-Grundkenntnisse erwerben kann.

  15. Astronomen bei der Arbeit - Live-Konferenz mit La Palma

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.

    2012-02-01

    "Wie kann man sich die nächtliche Arbeit eines Astronomen am Teleskop vorstellen?" Diese Frage stellen sich viele wissenschaftlich interessierte Menschen, die noch kein professionelles Observatorium besuchen konnten. Das multimediale Experiment "Call a Scientist" verband Besucher einer österreichischen Amateursternwarte live mit dem Großobservatorium in La Palma und brachte damit einer interessierten Öffentlichkeit seltene Einblicke in die Arbeitsweise der modernen Astronomie nahe.

  16. Kommunikation mit Mitarbeitern

    NASA Astrophysics Data System (ADS)

    Spychala, Anne; Fleischmann, Jürgen

    Kommunikation ist der Austausch von Nachrichten und Informationen zwischen Mitarbeitern eines Unternehmens (O'Hair et al. 1997). Dieser Austausch kann persönlich, aber z.B. auch per Telefon, E-Mail oder durch Computersysteme erfolgen. In diesem Kapitel betrachten wir die persönliche Kommunikation zwischen Vorgesetzten und Mitarbeitern. Zur persönlichen Kommunikation mit Mitarbeitern zählen sowohl formelle Gespräche mit Mitarbeitern als auch eher informelle Gespräche zwischen Tür und Angel. Die Gespräche können dabei mit einzelnen Mitarbeitern (z.B. jährliches Mitarbeitergespräch) oder mit Gruppen von Mitarbeitern (z.B. regelmäßige Projekt- oder Teambesprechungen) stattfinden.

  17. Grundlegende Steuerungsverfahren im heterogenen Logistiknetz mit Kanban

    NASA Astrophysics Data System (ADS)

    Dickmann, Eva; Dickmann, Philipp; Lödding, Hermann; Möller, Niklas; Rücker, Thomas; Schneider, Herfried M.; Zäh, Michael F.

    In vielen Unternehmen werden heterogene (verschiedene) Steuerungen in einem abgestimmten Konzept kombiniert. Je nach Anwendungsfall und Rahmenbedingungen werden Kombinationen allgemein bekannter Steuerungen oder Steuerungsvarianten gemischt eingesetzt, um eine optimale Steuerung für unterschiedliche Fälle zu erreichen. Hierbei stehen neben den bekannten und weit verbreiteten Methoden, wie Material Requirements Planning (MRP) oder Kanban, auch weniger bekannte oder neue Methoden zur Auswahl, wie die Produktionssteuerung mit dezentraler, bestandsorientierter Fertigungsregelung (DBF). Kanban ist ein simples und effizientes Steuerungskonzept, das in der klassischen Form für spezifische einfache Anwendungsfälle umsetzbar ist. Hochentwickelte Steuerungsalgorithmen können helfen, komplexe Abläufe optimal abzubilden. Mit einer grundlegenden Vereinfachung der Abläufe kann allerdings in vielen Fällen ein wesentlich stärkerer und umfassender Verbesserungseffekt erzielt werden. Die wesentliche Fragestellung sollte folglich lauten: Warum ist der Ablauf nicht mit einer einfachen Steuerung wie Kanban abzubilden? Um die Vorteile des Konzepts auch in untypischen Bereichen anwenden zu können, sind jedoch verschiedene Varianten oder Kanban-ähnliche Steuerungsmethoden entstanden. Darüber hinaus sind in der Praxis hybride Steuerungen im Einsatz, welche so kombiniert werden, dass die Zusammensetzung anspruchsvolle Eigenschaftsbilder noch exakt abbildet. In der Praxis basieren die Steuerungsentscheidungen nur zu einem kleinen Teil auf den eigentlichen Steuerungsalgorithmen, wie sie uns das MRP-System zur Verfügung stellt. Moderne Steuerungswelten" schließen alle relevanten Informationsquellen in eine heterogene Entscheidungsmatrix mit ein. Letztlich zählt nicht, ob die Entscheidung auf den Informationen aus dem MRP-System oder auf Softfacts basierend getroffen wurde, sondern nur, ob die Entscheidung erfolgreich war.

  18. The Oracle of DEM

    NASA Astrophysics Data System (ADS)

    Gayley, Kenneth

    2013-06-01

    The predictions of the famous Greek oracle of Delphi were just ambiguous enough to seem to convey information, yet the user was only seeing their own thoughts. Are there ways in which X-ray spectral analysis is like that oracle? It is shown using heuristic, generic response functions to mimic actual spectral inversion that the widely known ill conditioning, which makes formal inversion impossible in the presence of random noise, also makes a wide variety of different source distributions (DEMs) produce quite similar X-ray continua and resonance-line fluxes. Indeed, the sole robustly inferable attribute for a thermal, optically thin resonance-line spectrum with normal abundances in CIE is its average temperature. The shape of the DEM distribution, on the other hand, is not well constrained, and may actually depend more on the analysis method, no matter how sophisticated, than on the source plasma. The case is made that X-ray spectra can tell us average temperature, and metallicity, and absorbing column, but the main thing it cannot tell us is the main thing it is most often used to infer: the differential emission measure distribution.

  19. MPD work at MIT

    NASA Technical Reports Server (NTRS)

    Martinez-Sanchez, Manuel

    1991-01-01

    MPD work at MIT is presented in the form of the view-graphs. The following subject areas are covered: the MIT program, its goals, achievements, and roadblocks; quasi one-dimensional modeling; two-dimensional modeling - transport effects and Hall effect; microscopic instabilities in MPD flows and modified two stream instability; electrothermal stability theory; separation of onset and anode depletion; exit plane spectroscopic measurements; phenomena of onset as performance limiter; explanations of onset; geometry effects on onset; onset at full ionization and its consequences; relationship to anode depletion; summary on self-field MPD; applied field MPD - the logical growth path; the case for AF; the challenges of AF MPD; and recommendations.

  20. Unfälle mit Kleintransportern

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Auf einer außerörtlichen Bundesstraße geriet ein mit vier Personen besetzter Pkw Toyota Corolla aus letztlich nicht vollständig geklärten Gründen ins Schleudern. Nachdem sich das Fahrzeug beträchtlich entgegen dem Uhrzeigersinn ausgedreht hatte, prallte ein entgegenkommender Kleintransporter VW T4 frontal an die rechte Flanke des Toyota. Der Transporter wurde gedreht, ausgehoben und durch einen Pkw Ford Escort unterfahren. Alle Fahrzeuge kamen in Kollisionsortnähe zum Endstand. Die vier Toyota-Insassen wurden getötet. Aus den anderen Fahrzeugen wurden sechs Personen überwiegend schwer verletzt. Unbeteiligte Zeugen waren nicht vorhanden.

  1. Unfälle mit Kleintransportern

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Auf einer außerörtlichen Bundesstraße geriet ein mit vier Personen besetzter Pkw Toyota Corolla aus letztlich nicht vollständig geklärten Gründen ins Schleudern. Nachdem sich das Fahrzeug beträchtlich entgegen dem Uhrzeigersinn ausgedreht hatte, prallte ein entgegenkommender Kleintransporter VW T4 frontal an die rechte Flanke des Toyota. Der Transporter wurde gedreht, ausgehoben und durch einen Pkw Ford Escort unterfahren. Alle Fahrzeuge kamen in Kollisionsortnähe zum Endstand. Die vier Toyota-Insassen wurden getötet. Aus den anderen Fahrzeugen wurden sechs Personen überwiegend schwer verletzt. Unbeteiligte Zeugen waren nicht vorhanden.

  2. Abdichtungen mit Bitumenbahnen

    NASA Astrophysics Data System (ADS)

    Rahn, Axel C.; Unger, Wolfram

    Das Werk Bauwerksabdichtung von Karl Lufsky, im allgemeinen Sprachgebrauch auch Der Lufsky genannt, war immer das Standardwerk für Flächenabdichtungen mit Bitumenwerkstoffen. Karl Lufsky war erst Mitarbeiter des Geschäftsführers Otto Latendorf der 1924 in Berlin gegründeten Firma ARIDO Abdichtungs-GmbH und später ihr Geschäftsführer [8.1]. Eine Baustelle war seit 1950 der Keller der neuen Sowjetischen Botschaft Unter den Linden. Eines Tages sprach dort einer der russischen Ingenieur-Offiziere Otto Latendorf an und fragte ihn, ob er wohl eine schriftliche Zusammenfassung aller technischen Probleme der bituminösen Bauwerksabdichtung für ihn verfassen könnte. Mit dieser Schrift würde er sich dann zu seinem Abschlussexamen in Moskau melden. Vergüten wollte er den Arbeitsaufwand mit Lebensmittellieferungen. Otto Latendorf willigte ein und machte sich gemeinsam mit Karl Lufsky an die Arbeit. Dies war offensichtlich der Impuls für Karl Lufsky, einige Zeit später im Leipziger Teubner Verlag die erste Auflage des Buchs "Bauwerksabdichtungen“ herauszugeben, womit der Grundstein gelegt wurde, aus einer "Moskauer Examensarbeit“ in den letzten 50 Jahren ein bedeutendes Fachbuch zu machen.

  3. Reisen im freien Fall - Teil 2: Das Zwillingsparadoxon aus dem Blickwinkel der ART

    NASA Astrophysics Data System (ADS)

    Sonne, Bernd; Weiß, Reinhard

    2013-07-01

    Nachdem wir uns mit den Prinzipien der ART und einigen Beispielen vertraut gemacht haben, kommen wir nun zur Berechnung des Zwillingsparadoxons aus Sicht des reisenden Zwillings. Dabei spielt das Äquivalenzprinzip eine große Rolle. Deshalb wird die Bewegungssituation noch einmal erläutert, diesmal aus Sicht von Katrin. Sie befindet sich in ihrem System S'in Ruhe. In ihrem System läuft die Zeit t'ab. Nach dem Start fühlt Katrin jedoch eine Kraft, die sie als Gravitationskraft interpretieren kann. Sie merkt es daran, dass sie in den Sitz gedrückt wird. Nach einiger Zeit werden die Triebwerke abgeschaltet, und das Raumschiff fliegt mit konstanter Geschwindigkeit weiter, Phase 2. Anschließend wird der Schub der Triebwerke solange umgekehrt, bis das Raumschiff irgendwo mit der Geschwindigkeit null am Umkehrpunkt U landet, Phase 3 (Abb. 15.1). Die Erde, auf der sich Michael befindet, bewegt sich mit x'(t') aus Sicht von Katrin im freien Fall von ihr weg, s. das Experiment mit dem steigenden Fahrstuhl in Abschn. 13.2.1.

  4. Hydrologic enforcement of lidar DEMs

    USGS Publications Warehouse

    Poppenga, Sandra K.; Worstell, Bruce B.; Danielson, Jeffrey J.; Brock, John C.; Evans, Gayla A.; Heidemann, H. Karl

    2014-01-01

    Hydrologic-enforcement (hydro-enforcement) of light detection and ranging (lidar)-derived digital elevation models (DEMs) modifies the elevations of artificial impediments (such as road fills or railroad grades) to simulate how man-made drainage structures such as culverts or bridges allow continuous downslope flow. Lidar-derived DEMs contain an extremely high level of topographic detail; thus, hydro-enforced lidar-derived DEMs are essential to the U.S. Geological Survey (USGS) for complex modeling of riverine flow. The USGS Coastal and Marine Geology Program (CMGP) is integrating hydro-enforced lidar-derived DEMs (land elevation) and lidar-derived bathymetry (water depth) to enhance storm surge modeling in vulnerable coastal zones.

  5. Therapie des metastasierten kastrationsresistenten Prostatakarzinoms mit Abirateronacetat im klinischen Alltag.

    PubMed

    Wolff, Johannes Maria

    2017-01-01

    Abirateronacetat, das in Kombination mit Prednison/Prednisolon verabreicht wird, spielt eine wichtige Rolle in der Therapie des metastasierten kastrationsresistenten Prostatakarzinoms. Im Folgenden wurden besondere Aspekte der Therapie im klinischen Alltag zusammengestellt. Sie betreffen unter anderem die Dosierung - auch vor dem Hintergrund der Markteinführung einer neuen Formulierung von Abirateronacetat. Hinzu kommt die Verträglichkeit, vor allem in Bezug auf kardiovaskuläre und Kortikoid-bedingte Nebenwirkungen. Des Weiteren werden Kriterien genannt, nach denen die Therapie nicht zu früh umgestellt werden sollte. © 2017 S. Karger GmbH, Freiburg.

  6. Mit Mathematik zu Mehr Intelligenz in der Logistik

    NASA Astrophysics Data System (ADS)

    Möhring, Rolf H.; Schenk, Michael

    Die Lösung logistischer Probleme ist ein wichtiger Aspekt menschlichen Handelns seit Menschen gemeinsam zielgerichtet tätig wurden. Die Grundlagen dessen, was wir heute Logistik nennen, entstammen dem militärischen Bereich. So basierte z. B. das römische Imperium in starkem Maße auf militärisch-logistischen Glanzleistungen. Ob damals bereits mathematische Überlegungen eine Rolle spielten, wissen wir heute nicht. Jedoch versuchte z. B. Napoleon, der mit den bedeutendsten Mathematikern seiner Zeit befreundet war, den Transport seiner Truppen und die Verbreitung von Informationen zu optimieren und strategisch einzusetzen.1,2

  7. Radar and Lidar Radar DEM

    NASA Technical Reports Server (NTRS)

    Liskovich, Diana; Simard, Marc

    2011-01-01

    Using radar and lidar data, the aim is to improve 3D rendering of terrain, including digital elevation models (DEM) and estimates of vegetation height and biomass in a variety of forest types and terrains. The 3D mapping of vegetation structure and the analysis are useful to determine the role of forest in climate change (carbon cycle), in providing habitat and as a provider of socio-economic services. This in turn will lead to potential for development of more effective land-use management. The first part of the project was to characterize the Shuttle Radar Topography Mission DEM error with respect to ICESat/GLAS point estimates of elevation. We investigated potential trends with latitude, canopy height, signal to noise ratio (SNR), number of LiDAR waveform peaks, and maximum peak width. Scatter plots were produced for each variable and were fitted with 1st and 2nd degree polynomials. Higher order trends were visually inspected through filtering with a mean and median filter. We also assessed trends in the DEM error variance. Finally, a map showing how DEM error was geographically distributed globally was created.

  8. Kompressionstherapie - Versorgungspraxis: Informationsstand von Patienten mit Ulcus cruris venosum.

    PubMed

    Protz, Kerstin; Heyer, Kristina; Dissemond, Joachim; Temme, Barbara; Münter, Karl-Christian; Verheyen-Cronau, Ida; Klose, Katharina; Hampel-Kalthoff, Carsten; Augustin, Matthias

    2016-12-01

    Eine Säule der kausalen Therapie bei Patienten mit Ulcus cruris venosum ist die Kompressionstherapie. Sie unterstützt die Abheilung, reduziert Schmerzen und Rezidive und steigert die Lebensqualität. Bislang existieren kaum wissenschaftliche Daten zu dem Versorgungsstand und fachspezifischem Wissen von Patienten mit Ulcus cruris venosum. Standardisierte Fragebögen wurden bundesweit in 55 Pflegediensten, 32 Arztpraxen, vier Wundzentren und -sprechstunden sowie einem Pflegetherapiestützpunkt von Patienten mit Ulcus cruris venosum bei Erstvorstellung anonym ausgefüllt. Insgesamt nahmen 177 Patienten (Durchschnittsalter 69,4 Jahre; 75,1 % Frauen) teil. Ein florides Ulcus cruris venosum bestand im Mittel 17 Monate. 31,1 % hatten keine Kompressionstherapie, 40,1 % Binden und 28,8 % Strümpfe. Bei der Bestrumpfung hatten 13,7 % Kompressionsklasse III, 64,7 % Kompressionsklasse II und 19,6 % Kompressionsklasse I. 70,6 % legten die Strümpfe nach dem Aufstehen an, 21,1 % trugen sie Tag und Nacht. 39,2 % bereiteten die Strümpfe Beschwerden. Lediglich 11,7 % hatten eine An- und Ausziehhilfe. Die Binden wurden im Mittel 40,7 Wochen getragen und bei 69 % nicht unterpolstert. Bei 2,8 % wurde der Knöchel- und Waden-Umfang zur Erfolgskontrolle gemessen. Venensport machten 45,9 %. Ein Drittel hatte keine Kompressionsversorgung, obwohl diese eine Basismaßnahme der Therapie des Ulcus cruris venosum ist. Zudem ist deren korrekte Auswahl und Anwendung angesichts der langen Bestandsdauer der Ulzerationen zu hinterfragen. Weiterführende Fachkenntnisse bei Anwendern und Verordnern sowie Patientenschulungen sind erforderlich. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  9. MIT-CSR XIS Project

    NASA Technical Reports Server (NTRS)

    1998-01-01

    This report outlines the proposers' progress toward MIT's contribution to the X-Ray Imaging Spectrometer (XIS) experiment on the Japanese ASTRO-E mission. The report discusses electrical system design, mechanical system design, and ground support equipment.

  10. Topologie und Dynamische Netzwerke: Anwendungen Der Optimierung MIT Zukunft

    NASA Astrophysics Data System (ADS)

    Leugering, Günter; Martin, Alexander; Stingl, Michael

    Die optimale Auslegung von Infrastrukturen z. B. bei der Verkehrsplanung und bei der Planung von Versorgungssystemen, die optimale Strukturierung bzw. Formgebung von Materialien und Werkstücken z. B. im Leichtbau sind aktuelle Themen angewandter Forschung. In beiden Bereichen wurde bis in die jüngste Zeit vornehmlich eine simulationsbasierte Optimierung auf der Grundlage einer Parameterjustierung vorgenommen, die oft wenig systematisch und zeit- und kostenintensiv ist. Stattdessen erweisen sich modellbasierte mathematische Optimierungsalgorithmen zusammen mit moderner numerischer Simulations-und Visualisierungstechnologie zunehmend als Katalysator neuer Technologien. Eine so verstandene Mathematische Optimierung kann bereits auf beeindruckende Erfolgsgeschichten verweisen und so den Anspruch als eine Zukunftsdisziplin behaupten. Diesem Anspruch trägt die Einrichtung des DFG-Schwerpunktprogramms 1253, Optimierung mit partiellen Differentialgleichungen’ im Jahre 2006 Rechnung, in dem über 25 Projekte im Bundesgebiet sowohl auf die theoretische Fundierung, als auch und insbesondere auf die Verzahnung zwischen Methodenentwicklung und numerischer Realisierung fokussieren. Forschung im Bereich der mathematischen Optimierung und Steuerung von Prozessen bzw. Eigenschaften, die mit Hilfe partieller Differentialgleichungen, so genannten, verteilten Systemen’, beschrieben werden, erfolgt im Kontext konkreter und exemplarischer Anwendungssituationen, die neue mathematische Herausforderungen markieren: Sicherheitsvorgaben etwa bei der Belastung von Gas- und Frischwasserleitungen oder solche für die Belastbarkeit von Verkehrsflugzeugen führen auf Druckbeschränkungen bzw.

  11. MIT research in telerobotics

    NASA Technical Reports Server (NTRS)

    Sheridan, T. B.

    1987-01-01

    Ongoing MIT research in telerobotics (vehicles capable of some autonomous sensing and manipulating, having some remote supervisory control by people) and teleoperation (vehicles for sensing and manipulating which are fully controlled remotely by people) is discussed. The current efforts mix human and artificial intelligence/control. The idea of adjustable impedance at either end of pure master-slave teleoperation, and simultaneous coordinated control of teleoperator/telerobotic systems which have more than six degrees of freedom (e.g., a combined vehicle and arm, each with five or six DOF) are discussed. A new cable-controlled parallel link arm which offers many advantages over conventional arms for space is briefly described. Predictor displays to compensate for time delay in teleoperator loops, the use of state estimation to help human control decisions in space, and ongoing research in supervisory command language are covered. Finally, efforts to build a human flyable real-time dynamic computer-graphic telerobot simulator are described. These projects represent most, but not all, of the telerobotics research in our laboratory, supported by JPL, NASA Ames and NOAA.

  12. MIT's interferometer CST testbed

    NASA Technical Reports Server (NTRS)

    Hyde, Tupper; Kim, ED; Anderson, Eric; Blackwood, Gary; Lublin, Leonard

    1990-01-01

    The MIT Space Engineering Research Center (SERC) has developed a controlled structures technology (CST) testbed based on one design for a space-based optical interferometer. The role of the testbed is to provide a versatile platform for experimental investigation and discovery of CST approaches. In particular, it will serve as the focus for experimental verification of CSI methodologies and control strategies at SERC. The testbed program has an emphasis on experimental CST--incorporating a broad suite of actuators and sensors, active struts, system identification, passive damping, active mirror mounts, and precision component characterization. The SERC testbed represents a one-tenth scaled version of an optical interferometer concept based on an inherently rigid tetrahedral configuration with collecting apertures on one face. The testbed consists of six 3.5 meter long truss legs joined at four vertices and is suspended with attachment points at three vertices. Each aluminum leg has a 0.2 m by 0.2 m by 0.25 m triangular cross-section. The structure has a first flexible mode at 31 Hz and has over 50 global modes below 200 Hz. The stiff tetrahedral design differs from similar testbeds (such as the JPL Phase B) in that the structural topology is closed. The tetrahedral design minimizes structural deflections at the vertices (site of optical components for maximum baseline) resulting in reduced stroke requirements for isolation and pointing of optics. Typical total light path length stability goals are on the order of lambda/20, with a wavelength of light, lambda, of roughly 500 nanometers. It is expected that active structural control will be necessary to achieve this goal in the presence of disturbances.

  13. MIT Space Engineering Research Center

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1990-01-01

    The Space Engineering Research Center (SERC) at MIT, started in Jul. 1988, has completed two years of research. The Center is approaching the operational phase of its first testbed, is midway through the construction of a second testbed, and is in the design phase of a third. We presently have seven participating faculty, four participating staff members, ten graduate students, and numerous undergraduates. This report reviews the testbed programs, individual graduate research, other SERC activities not funded by the Center, interaction with non-MIT organizations, and SERC milestones. Published papers made possible by SERC funding are included at the end of the report.

  14. Wiederbeginn nach dem Zweiten Weltkrieg

    NASA Astrophysics Data System (ADS)

    Strecker, Heinrich; Bassenge-Strecker, Rosemarie

    Dieses Kapitel schildert zunächst die Ausgangslage für die Statistik in Deutschland nach dem Zweiten Weltkrieg: Der statistische Dienst in den Besatzungszonen musste teilweise erst aufgebaut und der statistische Unterricht an den Hochschulen wieder in Gang gebracht werden. In dieser Lage ergriff der Präsident des Bayerischen Statistischen Landesamtes, Karl Wagner, tatkräftig unterstützt von Gerhard Fürst, dem späteren Präsidenten des Statistischen Bundesamtes, die Initiative zur Neugründung der Deutschen Statistischen Gesellschaft (DStatG). Die Gründungsversammlung 1948 im München wurde zu einem Meilenstein in der Geschichte der DStatG. Ziel war es, alle Statistiker zur Zusammenarbeit anzuregen, ihre Qualifikation an das internationale Niveau heranzuführen und die Anwendung neuerer statistischer Methoden in der Praxis zu fördern. Es folgten 24 Jahre fruchtbarer Arbeit unter Karl Wagner (1948-1960) und Gerhard Fürst (1960-1972). Der Beitrag skizziert die Statistischen Wochen, die Tätigkeit der Ausschüsse und die Veröffentlichungen in dieser Zeit.

  15. MIT January Operational Internship Experience

    NASA Technical Reports Server (NTRS)

    Bosanac, Natasha; DeVivero, Charlie; James, Jillian; Perez-Martinez, Carla; Pino, Wendy; Wang, Andrew; Willett, Ezekiel; Williams, Kwami

    2010-01-01

    This viewgraph presentation describes the MIT January Operational Internship Experience (JOIE) program. The topics include: 1) Landing and Recovery; 2) Transportation; 3) Shuttle Processing; 4) Constellation Processing; 5) External Tank; 6) Launch Pad; 7) Ground Operations; 8) Hypergolic Propellants; 9) Environmental; 10) Logistics; 11) Six Sigma; 12) Systems Engineering; and 13) Human Factors.

  16. Srtm Dem-Aided dem Extraction Method for Island and Reef

    NASA Astrophysics Data System (ADS)

    Chen, X. W.; Zhao, C.; Guo, H. T.; Lin, Y. Z.; Yu, D. H.

    2017-09-01

    An SRTM DEM-aided DEM extraction method for island and reef is proposed to solve the problem of island and reef DEM extraction based on satellite imagery. The SRTM DEM is fully integrated into this method, namely, it is used to provide initial elevation for DEM and also to mark the sea area points in order to avoid the adverse effect of sea area image on DEM extraction. When determining elevations of grid points, only the valid land area points (VLPs) are taken into account. On the basis of initial elevation, the image coordinates of VLPs in multi-view images are determined and precise coordinates of conjugate points are obtained based on least square matching, then ground coordinates of VLPs are acquired by forward intersection. Finally, the elevations of VLPs are determined based on these object space points through data interpolation, and the sea area points are set as a uniform value. Experimental results show that the method can effectively solve the problem of island and reef DEM extraction. It can effectively extract DEM from island and reef satellite images regardless of the land area proportion, and island and reef can be completely extracted. Accuracy of the extracted DEM would improve with the increase of DEM resolution; when the resolution is relative high, the accuracy is consistent with SRTM DEM. The computational efficiency depends on the land area proportion and DEM resolution.

  17. Unterrichtsversuche mit dem franzosischen Chanson (Instruction Experiments with the French Song)

    ERIC Educational Resources Information Center

    Overbeck-Bollnow, Renate

    1974-01-01

    Five teaching experiments with French songs, in grades 7, 8 and 9, are described. Aural understanding was practiced first, then use of the text. In the 9th grade, work on the content became most important, with the aim of correcting and expanding the common conception of France. (Text is in German.) (IFS/WGA)

  18. TanDEM-X high resolution DEMs and their applications to flow modeling

    NASA Astrophysics Data System (ADS)

    Wooten, Kelly M.

    Lava flow modeling can be a powerful tool in hazard assessments; however, the ability to produce accurate models is usually limited by a lack of high resolution, up-to-date Digital Elevation Models (DEMs). This is especially obvious in places such as Kilauea Volcano (Hawaii), where active lava flows frequently alter the terrain. In this study, we use a new technique to create high resolution DEMs on Kilauea using synthetic aperture radar (SAR) data from the TanDEM-X (TDX) satellite. We convert raw TDX SAR data into a geocoded DEM using GAMMA software [Werner et al., 2000]. This process can be completed in several hours and permits creation of updated DEMs as soon as new TDX data are available. To test the DEMs, we use the Harris and Rowland [2001] FLOWGO lava flow model combined with the Favalli et al. [2005] DOWNFLOW model to simulate the 3-15 August 2011 eruption on Kilauea's East Rift Zone. Results were compared with simulations using the older, lower resolution 2000 SRTM DEM of Hawaii. Effusion rates used in the model are derived from MODIS thermal infrared satellite imagery. FLOWGO simulations using the TDX DEM produced a single flow line that matched the August 2011 flow almost perfectly, but could not recreate the entire flow field due to the relatively high DEM noise level. The issues with short model flow lengths can be resolved by filtering noise from the DEM. Model simulations using the outdated SRTM DEM produced a flow field that followed a different trajectory to that observed. Numerous lava flows have been emplaced at Kilauea since the creation of the SRTM DEM, leading the model to project flow lines in areas that have since been covered by fresh lava flows. These results show that DEMs can quickly become outdated on active volcanoes, but our new technique offers the potential to produce accurate, updated DEMs for modeling lava flow hazards.

  19. Educational Outreach at MIT PSFC

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Thomas, P.; Censabella, V.

    2001-10-01

    At the MIT PSFC student and staff volunteers work together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science and engineering, the PSFC hosts a number of outreach activities throughout the year, including Middle and High School Outreach Days. Key to the success of these tours is the interactive ``C-Mod, Jr.," which helps students understand magnetic confinement in MIT's Alcator C-Mod tokamak. The PSFC also has an in-school science demonstration program on the theme of magnetism. As ``Mr. Magnet" Technical Supervisor Paul Thomas brings a truck-load of hands-on demonstrations to K-12 schools, challenging students to help him with experiments. While teaching fundamentals of magnetism and electricity he shows that science is fun for all, and that any student can have a career in science. This year he reached 77 schools -- 30,000 teachers and students. We have also collaborated with the MIT Museum to create an interactive plasma demonstration device which students and the general public can use to create plasmas from different gasses. Pinch and deflection magnets are moveable along the axis of the display, allowing investigation of the magnetic behavior of plasmas.

  20. Urban DEM generation, analysis and enhancements using TanDEM-X

    NASA Astrophysics Data System (ADS)

    Rossi, Cristian; Gernhardt, Stefan

    2013-11-01

    This paper analyzes the potential of the TanDEM-X mission for the generation of urban Digital Elevation Models (DEMs). The high resolution of the sensors and the absence of temporal decorrelation are exploited. The interferometric chain and the problems encountered for correct mapping of urban areas are analyzed first. The operational Integrated TanDEM-X Processor (ITP) algorithms are taken as reference. The ITP main product is called the raw DEM. Whereas the ITP coregistration stage is demonstrated to be robust enough, large improvements in the raw DEM such as fewer percentages of phase unwrapping errors, can be obtained by using adaptive fringe filters instead of the conventional ones in the interferogram generation stage. The shape of the raw DEM in the layover area is also shown and determined to be regular for buildings with vertical walls. Generally, in the presence of layover, the raw DEM exhibits a height ramp, resulting in a height underestimation for the affected structure. Examples provided confirm the theoretical background. The focus is centered on high resolution DEMs produced using spotlight acquisitions. In particular, a raw DEM over Berlin (Germany) with a 2.5 m raster is generated and validated. For this purpose, ITP is modified in its interferogram generation stage by adopting the Intensity Driven Adaptive Neighbourhood (IDAN) algorithm. The height Root Mean Square Error (RMSE) between the raw DEM and a reference is about 8 m for the two classes defining the urban DEM: structures and non-structures. The result can be further improved for the structure class using a DEM generated with Persistent Scatterer Interferometry. A DEM fusion is thus proposed and a drop of about 20% in the RMSE is reported.

  1. Operational TanDEM-X DEM calibration and first validation results

    NASA Astrophysics Data System (ADS)

    Gruber, Astrid; Wessel, Birgit; Huber, Martin; Roth, Achim

    2012-09-01

    In June 2010, the German TanDEM-X satellite was launched. Together with its twin satellite TerraSAR-X it flies in a close formation enabling single-pass SAR interferometry. The primary goal of the TanDEM-X mission is the derivation of a global digital elevation model (DEM) with unprecedented global accuracies of 10 m in absolute and 2 m in relative height. A significant calibration effort is required to achieve this high quality world-wide. In spite of an intensive instrument calibration and a highly accurate orbit and baseline determination, some systematic height errors like offsets and tilts in the order of some meters remain in the interferometric DEMs and have to be determined and removed during the TanDEM-X DEM calibration. The objective of this article is the presentation of an approach for the estimation of correction parameters for remaining systematic height errors applicable to interferometric height models. The approach is based on a least-squares block adjustment using the elevation of ICESat GLA 14 data as ground control points and connecting points of adjacent, overlapping DEMs as tie-points. In the first part its implementation in DLR's ground segment is outlined. In the second part the approach is applied and validated for two of the first TanDEM-X DEM test sites. Therefore, independent reference data, in particular high resolution reference DEMs and GPS tracks, are used. The results show that the absolute height errors of the TanDEM-X DEM are small in these cases, mostly in the order of 1-2 m. An additional benefit of the proposed block adjustment method is that it improves the relative accuracy of adjacent DEMs.

  2. Die Struktur von schlankem Materialfluss mit Lean Production Kanban und Innovationen

    NASA Astrophysics Data System (ADS)

    Scheid, Wolf-Michael

    In der Literatur wird Materialfluss überwiegend in Spezialdisziplinen betrachtet, etwa der Steuerungslogik, der Logistiktechnik oder dem Supply Chain Management. Ein charakterisierendes Merkmal des Materialflusses ist jedoch, dass er sich aus vielfältigen Einzelbausteinen zusammensetzt, die alle harmonisch abgestimmt sein müssen. Die maximal erreichbare Effizienz wird nicht durch Höchstleistungen in dem einen oder anderen Spezialthema bestimmt, sondern durch das schwächste Glied im gesamten komplexen Netzwerk. Den Schnittstellen zwischen den betroffenen Fachbereichen in einem Unternehmen kommt hier eine ganz besondere Bedeutung zu: Erst ein harmonischer Einklang ermöglicht hohe Effektivität. Dies setzt umfassendes Verständnis für interdisziplinäre Notwendigkeiten, ein hohes Maß an Abstimmung mit den operativen Prozessen und letztlich einen einvernehmlichen Umgang und den Respekt vor den Problemstellungen des Anderen voraus.

  3. Von Donuts und Zucker: Mit Neutronen biologische Makromoleküle erforschen

    NASA Astrophysics Data System (ADS)

    May, Roland P.

    2003-05-01

    Für die Erforschung von Biomolekülen bieten Neutronen einzigartige Eigenschaften. Vor allem ihre unterschiedliche Wechselwirkung mit dem natürlichen Wasserstoff und seinem schweren Isotop Deuterium ermöglicht tiefe Einblicke in Struktur, Funktion und Dynamik von Proteinen, Nukleinsäuren und Biomembranen. Bei vielen Fragestellungen zur Strukturaufklärung gibt es kaum oder keine Alternative zum Neutron. Das Institut Laue-Langevin trägt Bahnbrechendes zum Erfolg der Neutronen-Methoden in der Biologie bei.

  4. An assessment of TanDEM-X GlobalDEM over rural and urban areas

    NASA Astrophysics Data System (ADS)

    Koudogbo, Fifamè N.; Duro, Javier; Huber, Martin; Rudari, Roberto; Eddy, Andrew; Lucas, Richard

    2014-10-01

    Digital Elevation Model (DEM) is a key input for the development of risk management systems. Main limitation of the current available DEM is the low level of resolution. DEMs such as STRM 90m or ASTER are globally available free of charge, but offer limited use, for example, to flood modelers in most geographic areas. TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement), the first bistatic SAR can fulfil this gap. The mission objective is the generation of a consistent global digital elevation model with an unprecedented accuracy according to the HRTI-3 (High Resolution Terrain Information) specifications. The mission opens a new era in risk assessment. In the framework of ALTAMIRA INFORMATION research activities, the DIAPASON (Differential Interferometric Automated Process Applied to Survey Of Nature) processing chain has been successfully adapted to TanDEM-X CoSSC (Coregistered Slant Range Single Look Complex) data processing. In this study the capability of CoSSC data for DEM generation is investigated. Within the on-going FP7 RASOR project (Rapid Analysis and Spatialisation and Of Risk), the generated DEM are compared with Intermediate DEM derived from the TanDEM-X first global coverage. The results are presented and discussed.

  5. An introduction to MIT mission

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Wang, C.; Xu, J.

    2012-12-01

    MIT is a Chinese mission proposed to lunch following Double Star and KuaFu project. The mission targets at the material coupling of the earth's magnetosphere, ionosphere and thermosphere. Implementing the mission will further our understanding of the sun-earth system, characterize the impact of solar activity on Earth's space environment, improve the security for man-made spacecraft. The mission's science objectives include the mechanism and the origin of outflow oxygen ions and other related outstanding scientific questions. The mission plans four satellites: two of them have polar circular orbit at the lower attitude of 500km*1000km; the other two have other two have elliptical orbit of 6400km*43000km with angle 75°. These altitudes are the key regions for the acceleration of the outflow oxygen ions. The proposed payloads are particles detectors, field detectors, aurora and neutral imaging system. These payloads will measure the plasma compositions and the electromagnetic waves, therefore determine the key factors for the oxygen ions to gain energy and flow upward. In this paper, we report the detailed orbit, payload and the current status for the MIT mission.

  6. Topographic Avalanche Risk: DEM Sensitivity Analysis

    NASA Astrophysics Data System (ADS)

    Nazarkulova, Ainura; Strobl, Josef

    2015-04-01

    GIS-based models are frequently used to assess the risk and trigger probabilities of (snow) avalanche releases, based on parameters and geomorphometric derivatives like elevation, exposure, slope, proximity to ridges and local relief energy. Numerous models, and model-based specific applications and project results have been published based on a variety of approaches and parametrizations as well as calibrations. Digital Elevation Models (DEM) come with many different resolution (scale) and quality (accuracy) properties, some of these resulting from sensor characteristics and DEM generation algorithms, others from different DEM processing workflows and analysis strategies. This paper explores the impact of using different types and characteristics of DEMs for avalanche risk modeling approaches, and aims at establishing a framework for assessing the uncertainty of results. The research question is derived from simply demonstrating the differences in release risk areas and intensities by applying identical models to DEMs with different properties, and then extending this into a broader sensitivity analysis. For the quantification and calibration of uncertainty parameters different metrics are established, based on simple value ranges, probabilities, as well as fuzzy expressions and fractal metrics. As a specific approach the work on DEM resolution-dependent 'slope spectra' is being considered and linked with the specific application of geomorphometry-base risk assessment. For the purpose of this study focusing on DEM characteristics, factors like land cover, meteorological recordings and snowpack structure and transformation are kept constant, i.e. not considered explicitly. Key aims of the research presented here are the development of a multi-resolution and multi-scale framework supporting the consistent combination of large area basic risk assessment with local mitigation-oriented studies, and the transferability of the latter into areas without availability of

  7. Quality Test Various Existing dem in Indonesia Toward 10 Meter National dem

    NASA Astrophysics Data System (ADS)

    Amhar, Fahmi

    2016-06-01

    Indonesia has various DEM from many sources and various acquisition date spreaded in the past two decades. There are DEM from spaceborne system (Radarsat, TerraSAR-X, ALOS, ASTER-GDEM, SRTM), airborne system (IFSAR, Lidar, aerial photos) and also terrestrial one. The research objective is the quality test and how to extract best DEM in particular area. The method is using differential GPS levelling using geodetic GPS equipment on places which is ensured not changed during past 20 years. The result has shown that DEM from TerraSAR-X and SRTM30 have the best quality (rmse 3.1 m and 3.5 m respectively). Based on this research, it was inferred that these parameters are still positively correlated with the basic concept, namely that the lower and the higher the spatial resolution of a DEM data, the more imprecise the resulting vertical height.

  8. Konstruieren von Pkw-Karosserien: Grundlagen, Elemente und Baugruppen, Vorschriftenübersicht, Beispiele mit CATIA V4 und V5

    NASA Astrophysics Data System (ADS)

    Grabner, Jörg; Nothhaft, Richard

    Die Faszination, die vom Auto ausgeht, ist und bleibt ungebrochen. Entsprechend interessant ist es, sich vor dem Hintergrund konventioneller Konstruktionstechniken über die virtuelle Produktentwicklung von Pkw-Karosserien an modernen CAD-Arbeitsplätzen informieren zu können. Die Autoren führen in die Grundlagen ein und zeigen anhand von Beispielen und zahlreichen Abbildungen, wie mit dem System CATIA der Rohbau sowie die Ausstattung innen und au=C3=9Fen konstruiert werden. Darüber hinaus wird das so genannte "Package" an Beispielen beschrieben, also das Management und die Harmonisierung der Anforderungen an die Bauräume (z.

  9. Positive Werkzeuge mit hohem IQ

    NASA Astrophysics Data System (ADS)

    Luik, Matthias

    Fräsen ist ein Verfahren, auf welches im modernen Produktionsprozess nicht verzichtet werden kann. Dabei stellt die zunehmende Komplexität der zu fertigenden Bauteile ganz neue Herausforderungen an ein Werkzeug. Konnten früher Bauteile nur mit hohem Aufwand durch Erodieren oder Außenräumen hergestellt werden, müssen heute bereits Fräswerkzeuge für solche Bearbeitungsaufgaben aus Zeitund Kostengründen eingesetzt werden. Dies führt dazu, dass viele Bauteile heute in einer Aufspannung bearbeitbar sind, welche früher nur durch mehrmaliges Umspannen erzeugt werden konnten. Um Bearbeitungszeiten und -kosten dabei gering zu halten, müssen aber dennoch universelle Werkzeuge eingesetzt werden, welche für verschiedenste Bearbeitungsaufgaben ausgelegt sind.

  10. Plattenepithelkarzinom in Verbindung mit einer roten Tätowierung.

    PubMed

    Schmitz, Inge; Prymak, Oleg; Epple, Matthias; Ernert, Carsten; Tannapfel, Andrea

    2016-06-01

    Obwohl Tätowierungen in den letzten Jahren außerordentlich beliebt geworden sind, wurde in der Literatur bisher nur über wenige Fälle schwerer Reaktionen berichtet, die zu einer malignen Transformation führten. Dies steht im Kontrast zu der praktisch unüberschaubaren Zahl an Tätowierungen weltweit. Die Zusammensetzung der für Tätowierungen verwendeten Farbstoffe variiert stark, und selbst gleiche Farbtöne können unterschiedliche Komponenten enthalten. Das Ziel unserer Studie war es zu untersuchen, auf welche Weise Tätowierungen möglicherweise Hautkrebs auslösen können. Wir berichten über den seltenen Fall einer 24-jährigen Frau, bei der sich sieben Monate nachdem sie eine Tätowierung auf dem Fußrücken erhalten hatte in unmittelbarer Nähe des verwendeten roten Farbstoffs ein Plattenepithelkarzinom entwickelte. Die Komplikationen begannen mit einer unspezifischen Schwellung. Die Läsion wurde histologisch untersucht. Die Zusammensetzung des inkorporierten Farbstoffs wurde mittels Rasterelektronenmikroskopie in Kombination mit energiedispersiver Elementanalyse analysiert. Zur weiteren Charakterisierung wurden Thermogravimetrie und Pulverdiffraktometrie eingesetzt. Der Tätowierungsfarbstoff enthielt hauptsächlich Bariumsulfat; Spuren von Al, S, Ti, P, Mg und Cl ließen sich ebenfalls nachweisen. Bei der Analyse zeigten sich Pigmentgranula unterschiedlicher Größe. In seltenen Fällen kann Tätowierungstinte karzinogene Effekte haben, die multifaktoriell zu sein scheinen. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  11. Accuracy of geolocation and DEM for ASTER

    NASA Astrophysics Data System (ADS)

    Watanabe, Hiroshi

    2005-10-01

    Since the launch in December of 1999, ASTER (Advanced Thermal Emission and Reflection Radiometer) has collected more than 1,000,000 scenes of data and generated more than 10,000 DEM and ortho-rectified images (Level 3A) from them, covering 20% of the whole land. The relative and absolute accuracy of geolocation and DEM will be discussed by comparing GCPs (Ground Control Point), GIS (Geographic Information System) and other existing topographic map. ASTER has shown very high geometric accuracy even if any GCP is not available. Contributing factors to this high accuracy are the stability and knowledge of the space craft orbit and attitude, ASTER sensors geometry, information on the Earth movement, algorithm to calculate the line of site vectors, and so on. Discussion will also cover the applicability of the DEM and ortho-rectified image data, based on the accuracy, and the discussion on further improvement.

  12. Zeitlicher Verlauf der avaskulären Nekrose des Hüftkopfes bei Patienten mit Pemphigus vulgaris.

    PubMed

    Balighi, Kamran; Daneshpazhooh, Maryam; Aghazadeh, Nessa; Saeidi, Vahide; Shahpouri, Farzam; Hejazi, Pardis; Chams-Davatchi, Cheyda

    2016-10-01

    Pemphigus vulgaris (PV) wird in der Regel mit systemischen Corticosteroiden und Immunsuppressiva behandelt. Avaskuläre Nekrose (AVN) des Hüftkopfes ist eine gut bekannte schwerere Komplikation einer Corticosteroid-Therapie. Die Charakteristika dieser schweren Komplikation bei PV sind nach wie vor unbekannt. Nicht kontrollierte, retrospektive Untersuchung aller PV-bedingten AVN-Fälle, die in einer iranischen Klinik für bullöse Autoimmunerkrankungen zwischen 1985 und 2013 diagnostiziert wurden. Anhand der Krankenakten von 2321 untersuchten PV-Patienten wurden 45 Fälle (1,93 %) von femoraler AVN identifiziert. Dreißig davon waren Männer. Das mittlere Alter bei der Diagnose der AVN betrug 47,4 ± 14,2 Jahre. Der mittlere Zeitraum zwischen der Diagnose des PV und dem Einsetzen der AVN lag bei 25,3 ± 18,3 Monaten. Mit Ausnahme von acht Fällen (17,8 %) setzte die AVN bei der Mehrheit der Patienten innerhalb von drei Jahren nach Diagnose des PV ein. Die mittlere kumulative Dosis von Prednisolon bei Patienten mit AVN betrug 13.115,8 ± 7041,1 mg. Zwischen der Prednisolon-Gesamtdosis und dem Zeitraum bis zum Einsetzen der AVN bestand eine starke Korrelation (p = 0,001). Bei Patienten mit Alendronateinnahme in der Vorgeschichte war dieser Zeitraum signifikant kürzer (p = 0,01). Die AVN ist eine schwere Komplikation einer Corticosteroid-Behandlung bei Patienten mit PV. Sie wird bei 2 % der Patienten beobachtet und tritt vor allem in den ersten drei Behandlungsjahren auf. Bei Patienten, die höhere Dosen von Prednisolon erhalten, setzt die AVN tendenziell früher ein. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  13. The New Global Digital Elevation Model : TanDEM-X DEM and its Final Performance

    NASA Astrophysics Data System (ADS)

    Gonzalez, Carolina; Rizzoli, Paola; Martone, Michele; Wecklich, Christopher; Borla Tridon, Daniela; Bachmann, Markus; Fritz, Thomas; Wessel, Birgit; Krieger, Gerhard; Zink, Manfred

    2017-04-01

    Digital elevation models (DEMs) have become widely used in many scientific and commercial applications and there are several local products have been developed in the last years. They provide a representation of the topographic features of the landscape. The importance of them is known and valued in every geoscience field, but they have also vast use in navigation and in other commercial areas. The main goal of the TanDEM-X (TerraSARX add-on for Digital Elevation Measurements) mission is the generation of a global DEM, homogeneous in quality with unprecedented global accuracy and resolution, which has been completed in mid-2016. For over four years, the almost identical satellites TerraSAR-X and TanDEM-X acquired single-pass interferometric SAR image pairs, from which is it possible to derive the topographic height by unwrapping the interferometric phase, unaffected by temporal decorrelation. Both satellites have been flying in close formation with a flexible geometric configuration. An optimized acquisition strategy aimed at achieving an absolute vertical accuracy much better than 10 meters and a relative vertical accuracy of 2 m and 4 m for flat and steep terrain, respectively, within a horizontal raster of 12 m x 12 m, which slightly varies depending on the geographic latitude. In this paper, we assess the performance of the global Tandem-X DEM, characterized in terms of relative and absolute vertical accuracy. The coverage statistics are also discussed in comparison to the previous almost global but with lower resolution DEM provided by the Shuttle Radar Topography Mission (SRTM). The exceptional quality of the global DEM is confirmed by the obtained results and the global TanDEM-X DEM is now ready to be distributed to the scientific and commercial community.

  14. Meteorite. Urmaterie aus dem interplanetaren Raum.

    NASA Astrophysics Data System (ADS)

    Bühler, R. W.

    Contents: 1. Wie Irrlichter aus irdischen Dünsten. 2. Steine und Eisen aus dem Weltraum. 3. Die Meteoritenfunde in der Antarktis. 4. Einschläge auf die Erde. 5. Staubkörner und Riesenbrocken. 6. Systematik, Mineralogie, Petrologie, Zusammensetzung. 7. Ursprungsorte und wissenschaftliche Bedeutung der Meteorite. 8. Meteorite erkennen und konservieren.9. Meteoriten-Sammlungen in Europa.

  15. Unfälle mit Pkw

    NASA Astrophysics Data System (ADS)

    Burg, Heinz

    Der Verkehrsunfall ereignete sich innerorts auf einer Kreuzung mit rechts vor links Regelung. Es galt dort die allgemeine Geschwindigkeitsbegrenzung auf 50 km/h. Zur Unfallzeit war es hell und trocken. Die Fahrbahn hatte eine Schwarzdecke.

  16. Incorporating DEM uncertainty in coastal inundation mapping.

    PubMed

    Leon, Javier X; Heuvelink, Gerard B M; Phinn, Stuart R

    2014-01-01

    Coastal managers require reliable spatial data on the extent and timing of potential coastal inundation, particularly in a changing climate. Most sea level rise (SLR) vulnerability assessments are undertaken using the easily implemented bathtub approach, where areas adjacent to the sea and below a given elevation are mapped using a deterministic line dividing potentially inundated from dry areas. This method only requires elevation data usually in the form of a digital elevation model (DEM). However, inherent errors in the DEM and spatial analysis of the bathtub model propagate into the inundation mapping. The aim of this study was to assess the impacts of spatially variable and spatially correlated elevation errors in high-spatial resolution DEMs for mapping coastal inundation. Elevation errors were best modelled using regression-kriging. This geostatistical model takes the spatial correlation in elevation errors into account, which has a significant impact on analyses that include spatial interactions, such as inundation modelling. The spatial variability of elevation errors was partially explained by land cover and terrain variables. Elevation errors were simulated using sequential Gaussian simulation, a Monte Carlo probabilistic approach. 1,000 error simulations were added to the original DEM and reclassified using a hydrologically correct bathtub method. The probability of inundation to a scenario combining a 1 in 100 year storm event over a 1 m SLR was calculated by counting the proportion of times from the 1,000 simulations that a location was inundated. This probabilistic approach can be used in a risk-aversive decision making process by planning for scenarios with different probabilities of occurrence. For example, results showed that when considering a 1% probability exceedance, the inundated area was approximately 11% larger than mapped using the deterministic bathtub approach. The probabilistic approach provides visually intuitive maps that convey

  17. Incorporating DEM Uncertainty in Coastal Inundation Mapping

    PubMed Central

    Leon, Javier X.; Heuvelink, Gerard B. M.; Phinn, Stuart R.

    2014-01-01

    Coastal managers require reliable spatial data on the extent and timing of potential coastal inundation, particularly in a changing climate. Most sea level rise (SLR) vulnerability assessments are undertaken using the easily implemented bathtub approach, where areas adjacent to the sea and below a given elevation are mapped using a deterministic line dividing potentially inundated from dry areas. This method only requires elevation data usually in the form of a digital elevation model (DEM). However, inherent errors in the DEM and spatial analysis of the bathtub model propagate into the inundation mapping. The aim of this study was to assess the impacts of spatially variable and spatially correlated elevation errors in high-spatial resolution DEMs for mapping coastal inundation. Elevation errors were best modelled using regression-kriging. This geostatistical model takes the spatial correlation in elevation errors into account, which has a significant impact on analyses that include spatial interactions, such as inundation modelling. The spatial variability of elevation errors was partially explained by land cover and terrain variables. Elevation errors were simulated using sequential Gaussian simulation, a Monte Carlo probabilistic approach. 1,000 error simulations were added to the original DEM and reclassified using a hydrologically correct bathtub method. The probability of inundation to a scenario combining a 1 in 100 year storm event over a 1 m SLR was calculated by counting the proportion of times from the 1,000 simulations that a location was inundated. This probabilistic approach can be used in a risk-aversive decision making process by planning for scenarios with different probabilities of occurrence. For example, results showed that when considering a 1% probability exceedance, the inundated area was approximately 11% larger than mapped using the deterministic bathtub approach. The probabilistic approach provides visually intuitive maps that convey

  18. Auf der Suche nach dem Unendlichen.

    NASA Astrophysics Data System (ADS)

    Fraser, G.; Lillestøl, E.; Sellevåg, I.

    This book is a German translation by C. Ascheron and J. Urbahn, of "The search for infinity: solving the mysteries of the universe", published in 1994. Diese Buch beschreibt anschaulich die Meilensteine, die der Mensch seit der Antike auf der Suche nach dem Unendlichen erreicht und hinter sich gelassen hat. Es enthält Kurzbiographien der wichtigsten Forscher, verständlich geschriebene Texte sowie Erläuterungen der entscheidenen Fachtermini.

  19. Spaceborne radar interferometry for coastal DEM construction

    USGS Publications Warehouse

    Hong, S.-H.; Lee, C.-W.; Won, J.-S.; Kwoun, Oh-Ig; Lu, Zhiming

    2005-01-01

    Topographic features in coastal regions including tidal flats change more significantly than landmass, and are characterized by extremely low slopes. High precision DEMs are required to monitor dynamic changes in coastal topography. It is difficult to obtain coherent interferometric SAR pairs especially over tidal flats mainly because of variation of tidal conditions. Here we focus on i) coherence of multi-pass ERS SAR interferometric pairs and ii) DEM construction from ERS-ENVISAT pairs. Coherences of multi-pass ERS interferograms were good enough to construct DEM under favorable tidal conditions. Coherence in sand dominant area was generally higher than that in muddy surface. The coarse grained coastal areas are favorable for multi-pass interferometry. Utilization of ERS-ENVISAT interferometric pairs is taken a growing interest. We carried out investigation using a cross-interferometric pair with a normal baseline of about 1.3 km, a 30 minutes temporal separation and the height sensitivity of about 6 meters. Preliminary results of ERS-ENVISAT interferometry were not successful due to baseline and unfavorable scattering conditions. ?? 2005 IEEE.

  20. Sentinel-1 SAR DEM Deployment Mechanisms Recovery

    NASA Astrophysics Data System (ADS)

    Rivera, Laura; Compositzo, Carlos; Arregui, Ibon

    2015-09-01

    The Sentinel-1 mission is encompassed in the Copernicus programme and each of the satellites carries a C-band Synthetic Aperture Radar (SAR) to provide an all-weather, day-and-night supply of imagery of Earth’s surface.This paper is prepared to inform of the development of the Deployment Mechanisms (DEM) of the SAR that are launched packed in stacks and have to deploy in orbit.SENER has designed, manufactured, integrated and tested 8 deployment mechanisms (DEM), 4 for Sentinel- 1A, that were successfully deployed some hours after it was launched in April 2014 and another 4 for Sentinel- 1B that is envisaged to be launched next year 2016. Previously, GAIA satellite was launched in December 2013, the Sunshield that was successfully deployed after launch, was equipped, as the DEMs, with two Sener’s Harmonic Drive Rotary Actuators (HDRA’s). Hence, SENER HDRA actuators have now the flight heritage of six units.Each antenna consisted of 5 stacks (named A to E panels) that are stored around the satellite and deployed once in orbit as per Fig.1:Figure 1.SAR in stowed and deployed configuration.

  1. Minimally invasive thyroidectomy (MIT): indications and results.

    PubMed

    Docimo, Giovanni; Salvatore Tolone, Salvatore; Gili, Simona; d'Alessandro, A; Casalino, G; Brusciano, L; Ruggiero, Roberto; Docimo, Ludovico

    2013-01-01

    To establish if the indication for different approaches for thyroidectomy and the incision length provided by means of pre-operative assessment of gland volume and size of nodules resulted in safe and effective outcomes and in any notable aesthetic or quality-of-life impact on patients. Ninehundred eightytwo consecutive patients, undergoing total thyroidectomy, were enrolled. The thyroid volume and maximal nodule diameter were measured by means of ultrasounds. Based on ultrasounds findings, patients were divided into three groups: minimally invasive video assisted thyroidectomy (MIVAT), minimally invasive thyroidectomy (MIT) and conventional thyroidectomy (CT) groups. The data concerning the following parameters were collected: operative time, postoperative complications, postoperative pain and cosmetic results. The MIVAT group included 179 patients, MIT group included 592 patients and CT group included 211 patients. Incidence of complications did not differ significantly in each group. In MIVAT and MIT group, the perception of postoperative pain was less intense than CT group. The patients in the MIVAT (7±1.5) and MIT (8±2) groups were more satisfied with the cosmetic results than those in CT group (5±1.3) (p= <0.05). The MIT is a technique totally reproducible, and easily convertible to perform surgical procedures in respect of the patient, without additional complications, increased costs, and with better aesthetic results.

  2. Volcanic geomorphology using TanDEM-X

    NASA Astrophysics Data System (ADS)

    Poland, Michael; Kubanek, Julia

    2016-04-01

    Topography is perhaps the most fundamental dataset for any volcano, yet is surprisingly difficult to collect, especially during the course of an eruption. For example, photogrammetry and lidar are time-intensive and often expensive, and they cannot be employed when the surface is obscured by clouds. Ground-based surveys can operate in poor weather but have poor spatial resolution and may expose personnel to hazardous conditions. Repeat passes of synthetic aperture radar (SAR) data provide excellent spatial resolution, but topography in areas of surface change (from vegetation swaying in the wind to physical changes in the landscape) between radar passes cannot be imaged. The German Space Agency's TanDEM-X satellite system, however, solves this issue by simultaneously acquiring SAR data of the surface using a pair of orbiting satellites, thereby removing temporal change as a complicating factor in SAR-based topographic mapping. TanDEM-X measurements have demonstrated exceptional value in mapping the topography of volcanic environments in as-yet limited applications. The data provide excellent resolution (down to ~3-m pixel size) and are useful for updating topographic data at volcanoes where surface change has occurred since the most recent topographic dataset was collected. Such data can be used for applications ranging from correcting radar interferograms for topography, to modeling flow pathways in support of hazards mitigation. The most valuable contributions, however, relate to calculating volume changes related to eruptive activity. For example, limited datasets have provided critical measurements of lava dome growth and collapse at volcanoes including Merapi (Indonesia), Colima (Mexico), and Soufriere Hills (Montserrat), and of basaltic lava flow emplacement at Tolbachik (Kamchatka), Etna (Italy), and Kīlauea (Hawai`i). With topographic data spanning an eruption, it is possible to calculate eruption rates - information that might not otherwise be available

  3. Kompressionstherapie bei Patienten mit Ulcus cruris venosum.

    PubMed

    Dissemond, Joachim; Assenheimer, Bernd; Bültemann, Anke; Gerber, Veronika; Gretener, Silvia; Kohler-von Siebenthal, Elisabeth; Koller, Sonja; Kröger, Knut; Kurz, Peter; Läuchli, Severin; Münter, Christian; Panfil, Eva-Maria; Probst, Sebastian; Protz, Kerstin; Riepe, Gunnar; Strohal, Robert; Traber, Jürg; Partsch, Hugo

    2016-11-01

    Wund-D.A.CH. ist der Dachverband deutschsprachiger Fachgesellschaften, die sich mit den Thematiken der Wundbehandlung beschäftigen. Experten verschiedener Fachgesellschaften aus Deutschland, Österreich und der Schweiz haben nun einen aktuellen Konsens der Kompressionstherapie für Patienten mit Ulcus cruris venosum erstellt. In Europa ist das Ulcus cruris venosum eine der häufigsten Ursachen für chronische Wunden. Neben der konservativen und interventionellen Wund- und Venentherapie, ist die Kompressionstherapie die Basis der Behandlungsstrategien. Die Kompressionstherapie kann heute mit sehr unterschiedlichen Materialien und Systemen durchgeführt werden. Während in der Entstauungsphase insbesondere Verbände mit Kurzzugbinden oder Mehrkomponentensysteme zur Anwendung kommen, sind es anschließend überwiegend Ulkus-Strumpfsysteme. Eine weitere, bislang wenig verbreitete Alternative sind adaptive Kompressionsbandagen. Insbesondere für die Rezidivprophylaxe werden medizinische Kompressionsstrümpfe empfohlen. Durch die Vielzahl der heute zur Verfügung stehenden Behandlungsoptionen, kann für nahezu alle Patienten ein Konzept entwickelt werden, dass sich an den individuellen Bedürfnissen und Fähigkeiten orientiert und daher auch akzeptiert und durchgeführt wird. Die Kompressionstherapie ist für die Behandlung von Patienten mit Ulcus cruris venosum essentiell. In den letzten Jahren sind viele verschiedene Therapieoptionen verfügbar, die in den deutschsprachigen Ländern unterschiedlich angewendet oder durchgeführt werden. Daher soll dieser Expertenkonsens dazu beitragen, konkrete Empfehlungen für die praktische Durchführung der Kompressionstherapie von Patienten mit Ulcus cruris venosum darzustellen. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  4. Incentives in IT Yield Success at MIT.

    ERIC Educational Resources Information Center

    Hanson, Mary

    2001-01-01

    Describes the role of information technology (IT) at the Massachusetts Institute of Technology, explaining that attention to the unique characteristics of an MIT education and incentives for sustainable change are central to its IT efforts. Discusses various IT initiatives, such as Project Athena, provision on campus, international efforts, and…

  5. Wrestling with Pedagogical Change: The TEAL Initiative at MIT

    ERIC Educational Resources Information Center

    Breslow, Lori

    2010-01-01

    In the late 1990s, the physics department at the Massachusetts Institute of Technology (MIT) had a problem. The department was responsible for teaching the two required physics courses that are part of the General Institute Requirements (GIRs), MIT's core curriculum--Physics I (mechanics, or in MIT parlance, 8.01) and Physics II (electricity and…

  6. Precise Global DEM Generation by ALOS PRISM

    NASA Astrophysics Data System (ADS)

    Tadono, T.; Ishida, H.; Oda, F.; Naito, S.; Minakawa, K.; Iwamoto, H.

    2014-04-01

    The Japan Aerospace Exploration Agency (JAXA) generated the global digital elevation/surface model (DEM/DSM) and orthorectified image (ORI) using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi"), which was operated from 2006 to 2011. PRISM consisted of three panchromatic radiometers that acquired along-track stereo images. It had a spatial resolution of 2.5 m in the nadir-looking radiometer and achieved global coverage, making it a suitable potential candidate for precise global DSM and ORI generation. In the past 10 years or so, JAXA has conducted the calibration of the system corrected standard products of PRISM in order to improve absolute accuracies as well as to validate the high-level products such as DSM and ORI. In this paper, we introduce an overview of the global DEM/DSM dataset generation project, including a summary of ALOS and PRISM, in addition to the global data archive status. It is also necessary to consider data processing strategies, since the processing capabilities of the level 1 standard product and the high-level products must be developed in terms of both hardware and software to achieve the project aims. The automatic DSM/ORI processing software and its test processing results are also described.

  7. Computerunterstütztes Modellieren mit Musiknetzen

    NASA Astrophysics Data System (ADS)

    Levens, Ulla

    In der folgenden Ausführung geht es um eine Anwendung von Petri-Netzen im Bereich Musik. Ausgehend von der Implementierung einer speziellen Anwendung, dem Programmsystem ScoreSynth, wird das zugrundeliegende Konzept erläutert und anschließend an einem kleinen Beispiel veranschaulicht. Dieser Beitrag ist ein Auszug aus [Lev95b].

  8. DEM time series of an agricultural watershed

    NASA Astrophysics Data System (ADS)

    Pineux, Nathalie; Lisein, Jonathan; Swerts, Gilles; Degré, Aurore

    2014-05-01

    In agricultural landscape soil surface evolves notably due to erosion and deposition phenomenon. Even if most of the field data come from plot scale studies, the watershed scale seems to be more appropriate to understand them. Currently, small unmanned aircraft systems and images treatments are improving. In this way, 3D models are built from multiple covering shots. When techniques for large areas would be to expensive for a watershed level study or techniques for small areas would be too time consumer, the unmanned aerial system seems to be a promising solution to quantify the erosion and deposition patterns. The increasing technical improvements in this growth field allow us to obtain a really good quality of data and a very high spatial resolution with a high Z accuracy. In the center of Belgium, we equipped an agricultural watershed of 124 ha. For three years (2011-2013), we have been monitoring weather (including rainfall erosivity using a spectropluviograph), discharge at three different locations, sediment in runoff water, and watershed microtopography through unmanned airborne imagery (Gatewing X100). We also collected all available historical data to try to capture the "long-term" changes in watershed morphology during the last decades: old topography maps, soil historical descriptions, etc. An erosion model (LANDSOIL) is also used to assess the evolution of the relief. Short-term evolution of the surface are now observed through flights done at 200m height. The pictures are taken with a side overlap equal to 80%. To precisely georeference the DEM produced, ground control points are placed on the study site and surveyed using a Leica GPS1200 (accuracy of 1cm for x and y coordinates and 1.5cm for the z coordinate). Flights are done each year in December to have an as bare as possible ground surface. Specific treatments are developed to counteract vegetation effect because it is know as key sources of error in the DEM produced by small unmanned aircraft

  9. Berechnung des Hochfrequenzverhaltens komplexer Strukturen mit der Methode gekoppelter Streuparameter - CSC

    NASA Astrophysics Data System (ADS)

    Glock, H.-W.; Rothemund, K.; van Rienen, U.

    2004-05-01

    Es wird eine Methode zur Berechnung der Hochfrequenz-Eigenschaften komplexer Strukturen vorgestellt. Das Verfahren beruht auf der Zerlegung der Gesamtstruktur in einzelne einfachere Segmente, deren breitbandige S-Matrizen mit kommerziellen Programmen berechnet werden. Das Gesamtsystem kann von beliebiger Topologie sein, und die Zahl der die Segmente verkoppelnden Hohlleiter- Moden ist nicht begrenzt. Als Ergebnis steht bei offenen Strukturen deren vollständige S-Matrix, bei abgeschlossenen deren Resonanzeigenschaften zur Verfügung. Die theoretischen Grundlagen werden beschrieben und die Anwendung mit Beispielen aus dem Gebiet der Teilchenbeschleuniger und zu Eigenschaften schwach elliptisch geformter Resonatoren illustriert. A method called Coupled S-Parameter Calculation - CSC is described which is used to calculate the rf properties of complex structures, i.e. either their scattering (devices with ports) or their resonance properties. The method is based on the segmentation of the entire system into sections being less complex, the external calculation of the section’s broadband S-matrices, and a combination scheme, which is applicable to any topology and number of modes. The method’s principle is described. Examples from the field of particle accelerator cavities and about the properties of weakly elliptical resonators are given.

  10. Phonetische Korrektur mit dem Frequenzfiltergeraet SUVAG-Lingua (Phonetic Correction with the Frequency Filter Device SUVAG-Lingua)

    ERIC Educational Resources Information Center

    Kettemann, Bernhard

    1977-01-01

    Maintains that teaching phonetics should be aimed at enabling the learner to correct himself and that intonation, rhythm and suprasegmental phonemes have commonly been neglected. Describes the value and use of the SUVAG-Lingua Frequency Filter for correcting pronunciation, individually and in groups. (Text is in German.) (IFS/WGA)

  11. Uberlegungen zur Arbeit mit Strukturubungen nach dem "Tandemprinzip" (Reflections of Work with Structured Exercises Based on the "Tandem Principle")

    ERIC Educational Resources Information Center

    Leupold, Eynar

    1972-01-01

    The tandem principle grows from the belief that foreign languages can be mutually supportive and informative if taught together. The pairing of French and German students for pattern practice in each other's native language is a practical application of the principle. (RS)

  12. [Homöopathisch-phytotherapeutische Behandlung des Reizdarmsyndroms mit Magen-Darm-Entoxin N®: Eine Anwendungsbeobachtung].

    PubMed

    Märtens, Diane; Range, Natasha; Günnewich, Nils; Gruber, Nicola; Schmidt, Stefan

    2017-01-01

    Hintergrund: In dieser Anwendungsbeobachtung wird zum ersten Mal die Behandlung des Reizdarmsyndroms (RDS) mit einem homöopathisch-phytotherapeutischen Komplexpräparat beschrieben. Methodik: Ziel der 6-wöchigen Therapie mit dem Magen-Darm-Entoxin N® war die Reduzierung der RDS-Symptomatik sowie die Verbesserung der Lebensqualität. Zielkriterien waren die Veränderungen in der Irritable Bowel Syndrome - Severity Scoring System (IBS-SSS) und der Irritable Bowel Syndrome - Quality-of-Life Scale (IBS-QoL). Die Patient/innen (N = 41; Alter 44,0 ± 15,74 Jahre) wurden zu gleichen Teilen in einer Hausarztpraxis (N = 20) und einer Heilpraktikerpraxis (N = 21) rekrutiert. Ergebnisse: Der IBS-QoL-Score verringerte sich signifikant (prä: 35,9 ± 16,3; post: 20,1 ± 13,4; t = 8,504; p < 0,001). Die Effektstärke betrug 1,34 (Cohens d). Der IBS-SSS-Score verringerte sich ebenfalls signifikant (prä: 239,4 ± 83,4; post: 123,7 ± 80,9; t = 7,825; p < 0,001) mit einer Effektstärke von d = 1,24. Die Neben- und Wechselwirkungen waren minimal und signifikante Unterschiede zwischen beiden Praxen wurden nicht gefunden. Schlussfolgerungen: Magen-Darm-Entoxin N® ist eine sichere und sinnvolle Therapieoption bei der Behandlung des RDS. Allerdings sollten randomisierte kontrollierte Studien folgen, um die Spezifizität der Ergebnisse dieser Anwendungsbeobachtung zu stützen. © 2017 S. Karger GmbH, Freiburg.

  13. Der Einfluss von Alitretinoin auf die Lebensqualität bei Patienten mit schwerem chronischen Handekzem: FUGETTA - Beobachtungsstudie unter Praxisbedingungen.

    PubMed

    Augustin, Matthias; Thaçi, Diamant; Kamps, Anja

    2016-12-01

    Alitretinoin ist die einzige zugelassene Behandlung für schweres chronisches Handekzem (CHE), das refraktär gegenüber potenten topischen Corticosteroiden ist. Bei dieser Studie (FUGETTA) wurde die Wirksamkeit von leitliniengerecht angewendetem oralem Alitretinoin sowie dessen Einfluss auf die Lebensqualität (LQ) bei Patienten mit schwerem refraktärem CHE beurteilt. Multizentrische, offene, nichtinterventionelle Beobachtungsstudie, durchgeführt in Deutschland. Die Patienten wurden nach Ermessen ihres behandelnden Arztes mit Alitretinoin 10 mg oder 30 mg einmal täglich über maximal 24 Wochen behandelt. Die Wirksamkeit wurde anhand des Physician Global Assessment (PGA) und des Dermatology Life Quality Index (DLQI) bewertet. Zudem wurden unerwünschte Ereignisse (UE) erfasst. Die Studienpopulation bestand aus 658 Patienten (30 mg: n = 581; 10 mg: n = 77). Bei Beobachtungsbeginn litten die meisten Patienten (83 %) gemäß PGA an einem schweren CHE. Bei Beobachtungsende war das Handekzem bei 48 % der Patienten gemäß PGA vollständig oder fast vollständig abgeheilt (30 mg: 49 %; 10 mg: 43 %). Die mittlere Verbesserung des DLQI-Scores in Woche 24 betrug 58 % (30 mg: mittlere [SD] Veränderung gegenüber dem Ausgangswert -10,4 [8,04]) und 70 % (10 mg: mittlere [SD] Veränderung gegenüber dem Ausgangswert -10,8 [7,29]). Die Gesamtinzidenz von NW war niedrig und in den beiden Gruppen ähnlich. Alitretinoin führte zu einer schnellen, deutlichen Verbesserung der LQ bei Patienten mit schwerem CHE. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  14. Flight research with the MIT Daedalus prototype

    NASA Technical Reports Server (NTRS)

    Bussolari, Steven R.; Youngren, Harold H.; Langford, John S.

    1987-01-01

    The MIT Light Eagle human-powered aircraft underwent long-duration testing over Rogers Dry Lake in California during January, 1987. Designed as a prototype for the MIT Daedalus Project, the Light Eagle's forty-eight flights provided pilot training, established new distance records for human-powered flight, and provided quantitative data through a series of instrumented flight experiments. The experiments focused on: (1) evaluating physiological loads on the pilot, (2) determining airframe power requirements, and (3) developing an electronic flight control system. This paper discusses the flight test program, its results and their implications for the follow-on Daedalus aircraft, and the potential uses of the Light Eagle as a low Reynolds number testbed.

  15. Abdichtungen im Verbund mit Fliesen und Platten

    NASA Astrophysics Data System (ADS)

    Platts, Thomas

    Abdichtungen im Verbund mit Fliesen und Platten, im Folgenden auch als Verbundabdichtungen oder mit Kurzzeichen als AIV bezeichnet, haben sich in der Baupraxis insbesondere in Innenräumen wegen des vereinfachten konstruktiven Aufbaus gegenüber Bahnenabdichtungen nach DIN 18195-5 [14.1] in der Mehrzahl der Ausführungen durchgesetzt und bewährt. Sie können im Innen- und Außenbereich angeordnet werden und sind dadurch gekennzeichnet, dass die Nutzschicht in Boden- und Wandbereichen im Dünnbettverfahren unmittelbar auf die Abdichtung aufgebracht wird. Aufwändige Zwischenschichten oder Einbauteile wie armierter Putz, Telleranker etc. entfallen (Bild 14.1) und es lassen sich geringere Aufbauhöhen realisieren.

  16. BlazeDEM3D-GPU A Large Scale DEM simulation code for GPUs

    NASA Astrophysics Data System (ADS)

    Govender, Nicolin; Wilke, Daniel; Pizette, Patrick; Khinast, Johannes

    2017-06-01

    Accurately predicting the dynamics of particulate materials is of importance to numerous scientific and industrial areas with applications ranging across particle scales from powder flow to ore crushing. Computational discrete element simulations is a viable option to aid in the understanding of particulate dynamics and design of devices such as mixers, silos and ball mills, as laboratory scale tests comes at a significant cost. However, the computational time required to simulate an industrial scale simulation which consists of tens of millions of particles can take months to complete on large CPU clusters, making the Discrete Element Method (DEM) unfeasible for industrial applications. Simulations are therefore typically restricted to tens of thousands of particles with highly detailed particle shapes or a few million of particles with often oversimplified particle shapes. However, a number of applications require accurate representation of the particle shape to capture the macroscopic behaviour of the particulate system. In this paper we give an overview of the recent extensions to the open source GPU based DEM code, BlazeDEM3D-GPU, that can simulate millions of polyhedra and tens of millions of spheres on a desktop computer with a single or multiple GPUs.

  17. Mishap Investigation Team (MIT) - Barksdale AFB, Louisiana

    NASA Technical Reports Server (NTRS)

    Stepaniak, Philip

    2005-01-01

    The Shuttle Program is organized to support a Shuttle mishap using the resources of the MIT. The afternoon of Feb. 1, 2003, the MIT deployed to Barksdale AFB. This location became the investigative center and interim storage location for crewmembers received from the Lufkin Disaster Field Office (DFO). Working under the leadership of the MIT Lead, the medical team executed a short-term plan that included search, recovery, and identification including coordination with the Armed Forces Institute of Pathology Temporary operations was set up at Barksdale Air Force Base for two weeks. During this time, coordination with the DFO field recovery teams, AFIP personnel, and the crew surgeons was on going. In addition, the crewmember families and NASA management were updated daily. The medical team also dealt with public reports and questions concerning biological and chemical hazards, which were coordinated with SPACEHAB, Inc., Kennedy Space Center (KSC) Medical Operations and the Johnson Space Center (JSC) Space Medicine office. After operations at Barksdale were concluded the medical team transitioned back to Houston and a long-term search, recovery and identification plan was developed.

  18. MIT validation probe acceptance test procedure

    SciTech Connect

    Escamilla, S.A.

    1994-08-23

    As part of the Multi-Functional Instrument Trees (MITs) a Validation Probe is being fabricated by Los Alamos National Laboratories (LANL). The Validation Probe assembly is equipped with a Winch, depth counter, and a Resistance Temperature Detector (RTD) which will render a means for verifying the temperature readings of which will render a means for verifying the temperature readings of the MIT thermocouples. The purpose of this Acceptance Test Procedure (ATP) is to provide verification that the Validation Probe functions properly and accordingly to LANL design and specification. This ATP will be used for all Validation Probes procured from LANL. The ATP consists of a receiving inspection, RTD ambient temperature; RTD electrical failure, RTD insulation resistance, and accurate depth counter operation inspections. The Validation Probe is composed of an intank probe, a cable and winching system, and a riser extension (probe guide) which bolts onto the MIT. The validation`s thermal sensor is an RTD that is housed in a 0.062 inch diameter, magnesium oxide fill, 316 stainless steel tube. The sheath configuration provides a means for spring loading the sensor firmly against the validation tube`s inner wall. A 45 pound cylindrical body is connected above the sheath and is used as a force to lower the probe into the tank. This cylindrical body also provides the means to interconnect both electrically and mechanically to the winch system which lowers the probe to a specified location within the validation tube located in the tank.

  19. Mishap Investigation Team (MIT) - Barksdale AFB, Louisiana

    NASA Technical Reports Server (NTRS)

    Stepaniak, Philip

    2005-01-01

    The Shuttle Program is organized to support a Shuttle mishap using the resources of the MIT. The afternoon of Feb. 1, 2003, the MIT deployed to Barksdale AFB. This location became the investigative center and interim storage location for crewmembers received from the Lufkin Disaster Field Office (DFO). Working under the leadership of the MIT Lead, the medical team executed a short-term plan that included search, recovery, and identification including coordination with the Armed Forces Institute of Pathology Temporary operations was set up at Barksdale Air Force Base for two weeks. During this time, coordination with the DFO field recovery teams, AFIP personnel, and the crew surgeons was on going. In addition, the crewmember families and NASA management were updated daily. The medical team also dealt with public reports and questions concerning biological and chemical hazards, which were coordinated with SPACEHAB, Inc., Kennedy Space Center (KSC) Medical Operations and the Johnson Space Center (JSC) Space Medicine office. After operations at Barksdale were concluded the medical team transitioned back to Houston and a long-term search, recovery and identification plan was developed.

  20. Which DEM is the best for glaciology? -Evaluation of global-scale DEM products-

    NASA Astrophysics Data System (ADS)

    Nagai, Hiroto; Tadono, Takeo

    2017-04-01

    Digital elevation models (DEMs) are fundamental geospatial data to study glacier distribution, changes, dynamics, mass balance and various geomorphological conditions. This study evaluates latest global-scale free DEMs in order to clarify their superiority and inferiority in glaciological uses. Three DEMs are now available; the 1-arcsec. product obtained from the Shuttle Radar Topographic Mission (SRTM1), the second version of Global Digital Elevation Model of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER GDEM2), and the first resampled dataset acquired by the Advanced Land observing Satellite, namely ALOS World 3D-30m (AW3D30). These DEMs have common specifications of global coverage (<60°S/N for SRTM1), freely downloadable via internet, and 1-arcsec. ( 30 m) pixel spacing. We carried out quantitative accuracy evaluation and spatial analysis of missing data (i.e. "void") distribution for these DEMs. Elevation values of the three DEMs are validated at check points (CPs), where elevation was measured by Geospatial Information Authority of Japan, in (A) the Japan Alps (as steep mountains with glaciation), in (B) Mt. Fuji (as monotonous hillslope), and in (C) the Tone river basin (as an flat plain). In all study sites, AW3D30 has the smallest errors against the CP elevation values (A: -6.1±8.6 m, B: +0.1±3.9 m, C: +0.1±2.5 m as the mean value and standard deviation of elevation differences). SRTM1 is secondly accurate (A: -17.8±16.3 m, B: +1.3±6.4 m, C: +0.1±3.1 m,), followed by ASTER GDEM2 (A: -13.9±20.8 m, B: -3.9±10.0 m, C: +4.3±3.8 m,). This accuracy differences among the DEMs are greater in steeper terrains (A>B>C). In the Tone river basin, SRTM1 has equivalent accuracy to AW3D30. High resolution (2.5 m) of the original stereo-pair images for AW3D30 (i.e. ALOS PRISM imagery) contributes for the best absolute accuracy. Glaciers on rather flat terrains are usually distributed in higher latitude (e.g. Antarctica and Greenland

  1. Hydraulic fracturing - an attempt of DEM simulation

    NASA Astrophysics Data System (ADS)

    Kosmala, Alicja; Foltyn, Natalia; Klejment, Piotr; Dębski, Wojciech

    2017-04-01

    Hydraulic fracturing is a technique widely used in oil, gas and unconventional reservoirs exploitation in order to enable the oil/gas to flow more easily and enhance the production. It relays on pumping into a rock a special fluid under a high pressure which creates a set of microcracks which enhance porosity of the reservoir rock. In this research, attempt of simulation of such hydrofracturing process using the Discrete Element Method approach is presented. The basic assumption of this approach is that the rock can be represented as an assembly of discrete particles cemented into a rigid sample (Potyondy 2004). An existence of voids among particles simulates then a pore system which can be filled out by fracturing fluid, numerically represented by much smaller particles. Following this microscopic point of view and its numerical representation by DEM method we present primary results of numerical analysis of hydrofracturing phenomena, using the ESyS-Particle Software. In particular, we consider what is happening in distinct vicinity of the border between rock sample and fracking particles, how cracks are creating and evolving by breaking bonds between particles, how acoustic/seismic energy is releasing and so on. D.O. Potyondy, P.A. Cundall. A bonded-particle model for rock. International Journal of Rock Mechanics and Mining Sciences, 41 (2004), pp. 1329-1364.

  2. MIT-Skywalker: On the use of a markerless system.

    PubMed

    Goncalves, Rogerio S; Hamilton, Taya; Krebs, Hermano I

    2017-07-01

    This paper describes our efforts to employ the Microsoft Kinect as a low cost vision control system for the MIT-Skywalker, a robotic gait rehabilitation device. The Kinect enables an alternative markerless solution to control the MIT-Skywalker and allows a more user-friendly set-up. A study involving eight healthy subjects and two stroke survivors using the MIT-Skywalker device demonstrates the advantages and challenges of this new proposed approach.

  3. Kombinierte Hoch-/Niedrig-Dosis-Therapie mit systemischen Glukokor-tikoiden bei schweren Verlaufsformen der Alopecia areata im Kindesalter.

    PubMed

    Jahn-Bassler, Karin; Bauer, Wolfgang Michael; Karlhofer, Franz; Vossen, Matthias G; Stingl, Georg

    2017-01-01

    Schwere Verlaufsformen der Alopecia areata (AA) im Kindesalter sind aufgrund limitierter Optionen therapeutisch herausfordernd. Systemische, hochdosierte Glukokortikoide weisen die schnellste Ansprechrate auf, nach dem Absetzen kommt es allerdings zu Rezidiven. Eine längerfristige Hochdosis-Anwendung ist aufgrund der zu erwartenden Nebenwirkungen nicht empfehlenswert. Eine dauerhafte Steroiderhaltungstherapie unterhalb der Cushing-Schwellen-Dosis nach Bolustherapie könnte die Krankheitsaktivität ohne Nebenwirkungen längerfristig unterdrücken. Im Rahmen einer offenen Anwendungsbeobachtung wurden 13 Kinder mit schweren Formen der AA in diese Studie eingeschlossen. Bei sieben Kindern lag eine AA totalis/universalis vor, bei sechs eine multifokale AA mit Befall von mehr als 50 % der Kopfhaut. Das Therapieregime sah eine initiale Prednisolon-Dosierung von 2 mg/kg Körpergeweicht (KG) vor und wurde innerhalb von neun Wochen auf eine Erhaltungsdosierung unter der individuellen Cushing-Schwelle reduziert. Der Nachbeobachtungszeitraum betrug ein bis drei Jahre. Wir beobachteten in 62 % aller Fälle ein komplettes Nachwachsen der Haare. Die mittlere Dauer bis zum Ansprechen lag bei 6,6 Wochen und konnte mit der Erhaltungstherapie über den gesamten Beobachtungszeitraum aufrechterhalten werden. An Nebenwirkungen wurden ausschließlich eine Gewichtszunahme (1-3 kg) bei allen Behandelten sowie eine milde Steroidakne in 23 % der Fälle beobachtet. Die kombinierte Hoch-/Niedrig-Dosis-Therapie mit systemischen Glukokortikoiden mittels Prednisolon zeigte eine hohe, dauerhafte Ansprechrate ohne signifikante Nebenwirkungen. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  4. TanDEM-X DEMs and feature-tracking of Helheim and Kangerdlugssuaq glaciers in south-east Greenland

    NASA Astrophysics Data System (ADS)

    Bevan, Suzanne; Luckman, Adrian; Murray, Tavi

    2013-04-01

    We use sequences of TanDEM-X acquisitions over 'supersites' Helheim and Kangerdlugssuaq glaciers in south-east Greenland to generate interferometric digital elevation models (DEMs) and to feature-track surface displacement between image acquisitions. The high spatial resolution, day/night, and cloud-penetrating capabilities of the X-band SAR system enabled the production of more than 20 DEMs for each glacier with a spatial resolution of 8 m or better. The DEMs span the period June 2011 to March 2012, at 11-day intervals, with a few breaks. Time-lapse animations of Helheim DEMs reveal the development of troughs in surface elevation close to the front. The troughs propagate down flow and develop into the rifts from which calving takes place. On both glaciers, regions of high variance in elevation can be identified caused by the transit of crevasses. In addition, on Helheim, a 1 km wide band of high variance adjacent to the calving front may be interpreted as the response to tidal forcing of a partially floating tongue. In addition to the DEMs we will also present featured tracked high-quality surface velocity fields at a spatial resolution of 2 m coincident with the DEMs. On Helheim these velocity fields indicate a winter deceleration of less than 10% at a point 4 km behind the calving front.

  5. ABCB1-Gen-Polymorphismus in einer polnischen Kohorte ist mit Risiko für bullöses Pemphigoid assoziiert.

    PubMed

    Rychlik-Sych, Mariola; Barańska, Małgorzata; Dudarewicz, Michał; Skrętkowicz, Jadwiga; Żebrowska, Agnieszka; Owczarek, Jacek; Waszczykowska, Elżbieta

    2017-05-01

    Polymorphismen im ABCB1-Gen, das für das P-Glykoprotein kodiert, können die intrazelluläre Konzentration von Xenobiotika beeinflussen und so zur Entwicklung von Autoimmunerkrankungen, einschließlich des bullösen Pemphigoids (BP), beitragen. In der vorliegenden Studie sollte untersucht werden, ob in einer polnischen Kohorte die C3435T- und G2677T/A-Polymorphismen im ABCB1-Gen mit dem Risiko für ein BP assoziiert sind. Die Studie umfasste 71 Patienten mit BP und 156 gesunde Probanden. Der C3435T-Polymorphismus wurde mittels PCR-RFLP bestimmt und der G2677T/A-Polymorphismus mittels Allel-spezifischer PCR. Es gab zwar keine Korrelation zwischen dem C3435-Polymorphismus und dem BP-Risiko, aber wir konnten eine derartige Assoziation hinsichtlich des G2677T/A-Polymorphismus nachweisen. Das relative Risiko eines BP war bei Personen mit dem 2677TA-Genotyp um mehr als den Faktor fünf erhöht (OR = 5,52; p = 0,0063) und bei Trägern des 2677TT-Genotyps mehr als verdoppelt (OR = 2,40; p = 0,0076). Mit 2,40 (p = 0,000018) war die OR bei Trägern des 2677T-Allels ebenfalls erhöht. Die höhere Prävalenz des 2677GG-Genotyps und des 2677G-Allels bei der Kontrollgruppe sowie eine OR < 1,0 (0,22 beziehungsweise 0,33) legen eine Schutzfunktion des 2677G-Allels hinsichtlich der Ausbildung eines BP nahe. Die Ergebnisse der vorliegenden Studie zeigen, dass der G2677T/A-Polymorphismus im ABCB1-Gen das Risiko für die Entstehung eines BP beeinflussen könnte. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  6. MIT - Mighty Steps toward Energy Sustainability

    SciTech Connect

    Robinson, Alastair; Regnier, Cindy; Settlemyre, Kevin; Bosnic, Zorana

    2012-07-01

    Massachusetts Institute of Technology (MIT) partnered with the U.S. Department of Energy (DOE) to develop and implement solutions to retrofit existing buildings to reduce energy consumption by at least 30% as part of DOE’s Commercial Building Partnerships (CBP) Program.1 Lawrence Berkeley National Laboratory (LBNL) provided technical expertise in support of this DOE program. MIT is one of the U.S.’s foremost higher education institutions, occupying a campus that is nearly 100 years old, with a building floor area totaling more than 12 million square feet. The CBP project focused on improving the energy performance of two campus buildings, the Ray and Maria Stata Center (RMSC) and the Building W91 (BW91) data center. A key goal of the project was to identify energy saving measures that could be applied to other buildings both within MIT’s portfolio and at other higher education institutions. The CBP retrofits at MIT are projected to reduce energy consumption by approximately 48%, including a reduction of around 72% in RMSC lighting energy and a reduction of approximately 55% in RMSC server room HVAC energy. The energy efficiency measure (EEM) package proposed for the BW91 data center is expected to reduce heating, ventilation, and air-conditioning (HVAC) energy use by 30% to 50%, depending on the final air intake temperature that is established for the server racks. The RMSC, an iconic building designed by Frank Gehry, houses the Computer Science and Artificial Intelligence Laboratory, the Laboratory for Information and Decision Systems, and the Department of Linguistics and Philosophy.

  7. MIT Space Engineering Research Center testbed programs

    NASA Technical Reports Server (NTRS)

    Crawley, Edward F.; Miller, David W.

    1991-01-01

    The Space Engineering Research Center (SERC) at M.I.T., started in July 1988, has completed two and one-half years of research. This Semi-Annual Report presents annotated viewgraph material presented at the January 1991 Steering Committee and Technical Representative Review. The objective of the Space Engineering Research Center is to develop and disseminate a unified technology of controlled structures. There has been continued evolution of the concept of intelligent structures (including in this past year the first successful embedding of a microelectronic component into a structural element).

  8. The MIT Program, Competition, and Ethics

    NASA Astrophysics Data System (ADS)

    Bradt, Hale V.

    2013-01-01

    The MIT program in x-ray astronomy was, and still is, diverse and productive. Bruno Rossi and later George Clark, as the nominal leaders of the “x-ray astronomy group” created a “hands-off” culture wherein individual researchers could develop their own independent programs. Walter Lewin, Claude Canizares, and I as well as those in the next academic generations, e.g., Saul Rappaport and George Ricker, were able to thrive in this environment. MIT researchers were principal investigators or providers of x-ray instruments on sounding rockets and balloons in the 1960s and then in later years on nine satellite missions, OSO-7, SAS-3, HEAO-1, Einstein, ASCA, RXTE, Chandra, HETE-2, and Suzaku. Such a diverse program involved collaborations with other institutions and of course striving for primacy in discovery and competition for NASA resources. Looking back, I see a high degree of ethical behavior among the observational x-ray community during those years. In competition, we remembered that we might well be collaborating the following year and behaved accordingly. Many of us in the x-ray community had been friends since graduate school days and did not want to lose those relationships. Am I viewing the past through rose colored glasses? I think not. A vignette on this topic: In 1967, I was debating vigorously with Herb Gursky of AS&E about which institution, MIT or AS&E, should be the lead on the fourth paper (Oda et al. 1967, ApJ 148, L5) based on data from the 1966 AS&E rocket flight which had led to Allan Sandage’s (and Japanese) identification of Sco X-1 (Sandage, et al. 1966, ApJ. 146, 316). I and my Italian colleague, Gianfranco Spada, and our Japanese colleague, Minoru Oda, both then visiting MIT, had actively supported that flight. After one rather heated discussion with Herb about this, - I was the heated one; he always remained calm - he left my office saying: “Hale, however this comes out, let’s remain friends.” I treasured that comment and

  9. Spotlight COSMO-SkyMed DEM generation and validation

    NASA Astrophysics Data System (ADS)

    Lombardi, N.; Lorusso, R.; Milillo, G.

    2016-10-01

    This paper focuses on the generation of Digital Elevation Models (DEMs) with COSMO SkyMed Spotlight data in providing DEMs. In particular, the peculiarity of Spotlight data (affected from Doppler centroid drift) is investigated, and the use of the processing chain included in the Delft Object-oriented Radar Interferometric Software (DORIS [1]). The effects of not correctly handled Doppler drift is shown. The standard interferometric processing, without Doppler drift handling, has been applied to Spotlight image pairs, resulting in interferometric coherence loss in interferograms as we move away from scene center. So, the standard processing chain has been modified to take in account the Doppler centroid drift affecting Spotlight data and very high resolution and accuracy DEMs have been obtained. Some Spotlight image pairs have been processed and the obtained DEMs have been shown and analyzed proving the high details and product accuracy.

  10. Construction of lunar DEMs based on reflectance modelling

    NASA Astrophysics Data System (ADS)

    Grumpe, Arne; Belkhir, Fethi; Wöhler, Christian

    2014-06-01

    Existing lunar DEMs obtained based on laser altimetry or photogrammetric image analysis are characterised by high large-scale accuracies while their lateral resolution is strongly limited by noise or interpolation artifacts. In contrast, image-based photometric surface reconstruction approaches reveal small-scale surface detail but become inaccurate on large spatial scales. The framework proposed in this study therefore combines photometric image information of high lateral resolution and DEM data of comparably low lateral resolution in order to obtain DEMs of high lateral resolution which are also accurate on large spatial scales. Our first approach combines an extended photoclinometry scheme and a shape from shading based method. A novel variational surface reconstruction method further increases the lateral resolution of the DEM such that it reaches that of the underlying images. We employ the Hapke IMSA and AMSA reflectance models with two different formulations of the single-particle scattering function, such that the single-scattering albedo of the surface particles and optionally the asymmetry parameter of the single-particle scattering function can be estimated pixel-wise. As our DEM construction methods require co-registered images, an illumination-independent image registration scheme is developed. An evaluation of our framework based on synthetic image data yields an average elevation accuracy of the constructed DEMs of better than 20 m as long as the correct reflectance model is assumed. When comparing our DEMs to LOLA single track data, absolute elevation accuracies around 30 m are obtained for test regions that cover an elevation range of several thousands of metres. The proposed illumination-independent image registration method yields subpixel accuracy even in the presence of 3D perspective distortions. The pixel-wise reflectance parameters estimated simultaneously with the DEM reflect compositional contrasts between different surface units

  11. Feasibility Analysis of DEM Differential Method on Tree Height Assessment wit Terra-SAR/TanDEM-X Data

    NASA Astrophysics Data System (ADS)

    Zhang, Wangfei; Chen, Erxue; Li, Zengyuan; Feng, Qi; Zhao, Lei

    2016-08-01

    DEM Differential Method is an effective and efficient way for forest tree height assessment with Polarimetric and interferometric technology, however, the assessment accuracy of it is based on the accuracy of interferometric results and DEM. Terra-SAR/TanDEM-X, which established the first spaceborne bistatic interferometer, can provide highly accurate cross-track interferometric images in the whole global without inherent accuracy limitations like temporal decorrelation and atmospheric disturbance. These characters of Terra-SAR/TandDEM-X give great potential for global or regional tree height assessment, which have been constraint by the temporal decorrelation in traditional repeat-pass interferometry. Currently, in China, it will be costly to collect high accurate DEM with Lidar. At the same time, it is also difficult to get truly representative ground survey samples to test and verify the assessment results. In this paper, we analyzed the feasibility of using TerraSAR/TanDEM-X data to assess forest tree height with current free DEM data like ASTER-GDEM and archived ground in-suit data like forest management inventory data (FMI). At first, the accuracy and of ASTER-GDEM and forest management inventory data had been assessment according to the DEM and canopy height model (CHM) extracted from Lidar data. The results show the average elevation RMSE between ASTER-GEDM and Lidar-DEM is about 13 meters, but they have high correlation with the correlation coefficient of 0.96. With a linear regression model, we can compensate ASTER-GDEM and improve its accuracy nearly to the Lidar-DEM with same scale. The correlation coefficient between FMI and CHM is 0.40. its accuracy is able to be improved by a linear regression model withinconfidence intervals of 95%. After compensation of ASTER-GDEM and FMI, we calculated the tree height in Mengla test site with DEM Differential Method. The results showed that the corrected ASTER-GDEM can effectively improve the assessment accuracy

  12. MMPI and MIT Discriminators of Biogenic and Psychogenic Impotence

    ERIC Educational Resources Information Center

    Beutler, Larry E.; And Others

    1975-01-01

    Male patients complaining of impotence (N=32) were administered the Male Impotence Test (MIT) and the Minnesota Multiphasic Personality Inventory (MMPI). The results suggested that the MIT is without value for differentiating between psychogenic and biogenic impotence, whereas two rules from the MMPI appropriately classified 90 percent of the…

  13. MMPI and MIT Discriminators of Biogenic and Psychogenic Impotence

    ERIC Educational Resources Information Center

    Beutler, Larry E.; And Others

    1975-01-01

    Male patients complaining of impotence (N=32) were administered the Male Impotence Test (MIT) and the Minnesota Multiphasic Personality Inventory (MMPI). The results suggested that the MIT is without value for differentiating between psychogenic and biogenic impotence, whereas two rules from the MMPI appropriately classified 90 percent of the…

  14. Physik gestern und heute: Visualisierung mit der Schlierenmethode

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-07-01

    Der Name des österreichischen Forschers Ernst Mach ist heute noch mit der Schallgeschwindigkeit verbunden. Diese Auszeichnung resultiert aus Machs Untersuchungen, wie sich Projektile mit Überschallgeschwindigkeit durch die Luft bewegen. Gerade in jüngster Zeit hat die Anwendung derartiger Methoden durch technische Modifikationen wieder einen Aufschwung erfahren.

  15. Implementation of Microfiche Image Transmission System (MITS): A multifaceted assessment of demonstration installation

    NASA Astrophysics Data System (ADS)

    Sheposh, J. P.; Hulton, V. N.

    1983-06-01

    A multifaceted approach was employed to evaluate the introduction and implementation of a technological system--the microfiche image transmission system (MITS). Four different aspects of the demonstration installation were investigated: (1) operators' perception of MITS, (2) the requesters' acceptance of the services provided, (3) image quality, and (4) management's evaluation of the MITS implementation. The results revealed that the operators' perceptions of MITS were positive, the requesters regarded MITS as highly satisfactory, the image quality of the facsimile input fiche was judged superior to the MITS output, and the managers and developers regarded the MITS implementation as a success. Issues concerning widespread application of MITS were seen as premature at this time.

  16. Enhanced ASTER DEMs for Decadal Measurements of Glacier Elevation Changes

    NASA Astrophysics Data System (ADS)

    Girod, L.; Nuth, C.; Kääb, A.

    2016-12-01

    Elevation change data is critical to the understanding of a number of geophysical processes, including glaciers through the measurement their volume change. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system on-board the Terra (EOS AM-1) satellite has been a unique source of systematic stereoscopic images covering the whole globe at 15m resolution and at a consistent quality for over 15 years. While satellite stereo sensors with significantly improved radiometric and spatial resolution are available today, the potential of ASTER data lies in its long consistent time series that is unrivaled, though not fully exploited for change analysis due to lack of data accuracy and precision. ASTER data are strongly affected by attitude jitter, mainly of approximately 4 and 30 km wavelength, and improving the generation of ASTER DEMs requires removal of this effect. We developed MMASTER, an improved method for ASTER DEM generation and implemented it in the open source photogrammetric library and software suite MicMac. The method relies on the computation of a rational polynomial coefficients (RPC) model and the detection and correction of cross-track sensor jitter in order to compute DEMs. Our sensor modeling does not require ground control points and thus potentially allows for automatic processing of large data volumes. When compared to ground truth data, we have assessed a ±5m accuracy in DEM differencing when using our processing method, improved from the ±30m when using the AST14DMO DEM product. We demonstrate and discuss this improved ASTER DEM quality for a number of glaciers in Greenland (See figure attached), Alaska, and Svalbard. The quality of our measurements promises to further unlock the underused potential of ASTER DEMs for glacier volume change time series on a global scale. The data produced by our method will thus help to better understand the response of glaciers to climate change and their influence on runoff and sea level.

  17. The MIT short-wavelength laser project

    NASA Astrophysics Data System (ADS)

    Hagelstein, P.; Basu, S.; Muendel, M.; Braud, J. P.; Kaushik, S.; Tauber, D.

    The present status of the project follows: the Nd:glass power amplifier was constructed and brought from LLNL to MIT; gain measurements were performed, and work on the associated optics is currently underway. The vacuum chamber was built and successfully tested. The optics for the target alignment system were redesigned, fabricated, and partially assembled; the electronics are now being brought together. EUV spectrometers for use as laser diagnostics are under development; these incorporate both commercially available gratings as well as novel, in-house designs. Work on laser cavities has yielded an greatly improved understanding of the difficulties involved in using whispering gallery optics. An earlier analysis of soft x ray frequency conversion was refined. A numerical study of plasma kinetics has elucidated the physics of transiently pumped x ray lasers.

  18. MIT microwiggler for free electron laser applications

    SciTech Connect

    Catravas, P.; Stoner, R.; Blastos, J.; Sisson, D.; Mastovsky, I.; Bekefi, G.; Wang, X.J.; Fisher, A.

    1995-07-01

    A microwiggler-based FEL permits operation at shorter wavelengths with a reduction in the size and cost of the device. The MIT microwiggler is a pulsed ferromagnetic-core electromagnet with 70 periods of 8.8 mm each which generates an on-axis peak magnetic field of 4.2 kG. The pulse repetition rate is 0.5 Hz with FWHM 0.5 msec. The microwiggler is characterized by extensive tunability. We employed a novel tuning regimen through which the rms spread in peak amplitudes was reduced to 0.08 % the lowest ever achieved in a sub-cm period magnetic field. The microwiggler is a serviceable scientific apparatus: spontaneous emission has been observed for wavelengths of 700--800 nm using a 40 MeV beam from the Accerator Test Facility LINAC at BNL.

  19. Teaching ``The Physics of Energy'' at MIT

    NASA Astrophysics Data System (ADS)

    Jaffe, Robert

    2009-05-01

    New physics courses on energy are popping up at colleges and universities across the country. Many require little or no previous physics background, aiming to introduce a broad audience to this complex and critical problem, often augmenting the scientific message with economic and policy discussions. Others are advanced courses, focussing on highly specialized subjects like solar voltaics, nuclear physics, or thermal fluids, for example. About two years ago Washington Taylor and I undertook to develop a course on the ``Physics of Energy'' open to all MIT students who had taken MIT's common core of university level calculus, physics, and chemistry. By avoiding higher level prerequisites, we aimed to attract and make the subject relevant to students in the life sciences, economics, etc. --- as well as physical scientists and engineers --- who want to approach energy issues in a sophisticated and analytical fashion, exploiting their background in calculus, mechanics, and E & M, but without having to take advanced courses in thermodynamics, quantum mechanics, or nuclear physics beforehand. Our object was to interweave teaching the fundamental physics principles at the foundations of energy science with the applications of those principles to energy systems. We envisioned a course that would present the basics of statistical, quantum, and fluid mechanics at a fairly sophisticated level and apply those concepts to the study of energy sources, conversion, transport, losses, storage, conservation, and end use. In the end we developed almost all of the material for the course from scratch. The course debuted this past fall. I will describe what we learned and what general lessons our experience might have for others who contemplate teaching energy physics broadly to a technically sophisticated audience.

  20. Comparison of Calorimetry: MIT and Fleischmann-Pons Systems

    NASA Astrophysics Data System (ADS)

    Miles, Melvin H.; Hagelstein, Peter

    2011-03-01

    The history of cold fusion shows that the MIT heat conduction calorimetry in 1990 reported a sensitivity of 40 mW while the Fleischmann-Pons Dewar calorimetry achieved a sensitivity of 0.1 mW. Additional information about the MIT calorimetry allows a more detailed analysis. The major finding is that the MIT calorimetric cell was so well insulated with glass wool (2.5 cm in thickness) that the major heat transport pathway was out of the cell top rather than from the cell into the constant temperature water bath. It can be shown for the MIT calorimeter that 58% of the heat transport was through the cell top and 42% was from the cell into the water bath. Analysis of the Fleischmann-Pons Dewar cell shows that under conditions similar to the MIT experiments, almost all of the heat flow would be from the Dewar calorimetric cell to the constant temperature water bath. Furthermore, the sensitivity of the Fleischmann- Pons temperature measurements was 0.001 K versus 0.1 K for the MIT calorimetric cell. Evaluations of the calorimetric equations and data analysis methods leads to the conclusion that the Fleischmann-Pons calorimetry was far superior to that of MIT.

  1. The effects of wavelet compression on Digital Elevation Models (DEMs)

    USGS Publications Warehouse

    Oimoen, M.J.

    2004-01-01

    This paper investigates the effects of lossy compression on floating-point digital elevation models using the discrete wavelet transform. The compression of elevation data poses a different set of problems and concerns than does the compression of images. Most notably, the usefulness of DEMs depends largely in the quality of their derivatives, such as slope and aspect. Three areas extracted from the U.S. Geological Survey's National Elevation Dataset were transformed to the wavelet domain using the third order filters of the Daubechies family (DAUB6), and were made sparse by setting 95 percent of the smallest wavelet coefficients to zero. The resulting raster is compressible to a corresponding degree. The effects of the nulled coefficients on the reconstructed DEM are noted as residuals in elevation, derived slope and aspect, and delineation of drainage basins and streamlines. A simple masking technique also is presented, that maintains the integrity and flatness of water bodies in the reconstructed DEM.

  2. Local validation of EU-DEM using Least Squares Collocation

    NASA Astrophysics Data System (ADS)

    Ampatzidis, Dimitrios; Mouratidis, Antonios; Gruber, Christian; Kampouris, Vassilios

    2016-04-01

    In the present study we are dealing with the evaluation of the European Digital Elevation Model (EU-DEM) in a limited area, covering few kilometers. We compare EU-DEM derived vertical information against orthometric heights obtained by classical trigonometric leveling for an area located in Northern Greece. We apply several statistical tests and we initially fit a surface model, in order to quantify the existing biases and outliers. Finally, we implement a methodology for orthometric heights prognosis, using the Least Squares Collocation for the remaining residuals of the first step (after the fitted surface application). Our results, taking into account cross validation points, reveal a local consistency between EU-DEM and official heights, which is better than 1.4 meters.

  3. Final Technical Report for the MIT Annular Fuel Research Project

    SciTech Connect

    Mujid S. Kazimi; Pavel Hejzlar

    2008-01-31

    MIT-NFC-PR-082 (January 2006) Abstract This summary provides an overview of the results of the U.S. DOE funded NERI (Nuclear Research ENergy Initiative) program on development of the internally and externally cooled annular fuel for high power density PWRs. This new fuel was proposed by MIT to allow a substantial increase in poer density (on the order of 30% or higher) while maintaining or improving safety margins. A comprehensive study was performed by a team consisting of MIT (lead organization), Westinghuse Electric Corporation, Gamma Engineering Corporation, Framatome ANP(formerly Duke Engineering) and Atomic Energy of Canada Limited.

  4. CapDEM Exercise Gamma: Results and Discussion

    DTIC Science & Technology

    2011-06-01

    internal team’ using CapDEM towards the reality of external groups using the CapDEM approach to address their own problem by themselves. The results...enable and support different internal and external configurations of the classified CEE requires further study, including both technical and security...qu’épreuve et évaluation tout à fait indépendantes, l’Exercice a moins mis l’accent sur une « équipe interne » utilisant l’approche DIGCap et il a plutôt

  5. Discrete Element Modeling (DEM) of Triboelectrically Charged Particles: Revised Experiments

    NASA Technical Reports Server (NTRS)

    Hogue, Michael D.; Calle, Carlos I.; Curry, D. R.; Weitzman, P. S.

    2008-01-01

    In a previous work, the addition of basic screened Coulombic electrostatic forces to an existing commercial discrete element modeling (DEM) software was reported. Triboelectric experiments were performed to charge glass spheres rolling on inclined planes of various materials. Charge generation constants and the Q/m ratios for the test materials were calculated from the experimental data and compared to the simulation output of the DEM software. In this paper, we will discuss new values of the charge generation constants calculated from improved experimental procedures and data. Also, planned work to include dielectrophoretic, Van der Waals forces, and advanced mechanical forces into the software will be discussed.

  6. Geodetic mass balance of the Patagonian Icefields from STRM and TanDEM-X DEMs

    NASA Astrophysics Data System (ADS)

    Abdel Jaber, W.; Floricioiu, D.; Rott, H.

    2016-12-01

    The Northern and Southern Patagonian Icefields (NPI & SPI), represent the largest mid-latitude ice masses in the Southern Hemisphere. They are mostly drained by outlet glaciers with fronts calving into fresh water lakes or Pacific fjords. Both icefields were affected by significant downwasting in the last decades, as confirmed by published mass change trends obtained by means of gravimetric measurements and geodetic methods. Given their unique characteristics and the significant contribution to sea level rise per unit of area, they represent a fundamental barometer for climate research. The Shuttle Radar Topography Mission (SRTM) of 2000 provided the most complete and accurate Digital Elevation Model (DEM) at the time covering the entire globe from 56°S to 60°N. The present TanDEM-X mission shares the same objective aiming at a global coverage with much higher resolution and accuracy. Their combination leads to a unique multitemporal elevation dataset based solely on SAR single pass bistatic interferometry characterized by 11 to 16 year time span: an ideal setup for monitoring long-term large-scale geophysical phenomena. Using this dataset, detailed and extensive ice elevation change maps were obtained for the 12900 km² SPI for the observation period 2000 - 2011/2012 and for the 3900 km² NPI for the period 2000 - 2014. These maps were used to compute the glacier mass balance of the icefields through the geodetic method. Particular emphasis was set on the estimation of the uncertainty of the geodetic mass balance by quantifying all relevant sources of error. Among these, signal penetration into dry ice and snow can affect considerably radar elevation measurements. For this purpose the backscattering coefficient of the acquisitions along with concurrent meteorological data were analyzed to assess the conditions of the icefield surface. Mass change rates of -3.96±0.14 Gt a-1 and of -13.14±0.42 Gt a-1 (excluding subaqueous loss) were obtained for NPI and SPI

  7. Precise baseline determination for the TanDEM-X mission

    NASA Astrophysics Data System (ADS)

    Koenig, Rolf; Moon, Yongjin; Neumayer, Hans; Wermuth, Martin; Montenbruck, Oliver; Jäggi, Adrian

    The TanDEM-X mission will strive for generating a global precise Digital Elevation Model (DEM) by way of bi-static SAR in a close formation of the TerraSAR-X satellite, already launched on June 15, 2007, and the TanDEM-X satellite to be launched in May 2010. Both satellites carry the Tracking, Occultation and Ranging (TOR) payload supplied by the GFZ German Research Centre for Geosciences. The TOR consists of a high-precision dual-frequency GPS receiver, called Integrated GPS Occultation Receiver (IGOR), and a Laser retro-reflector (LRR) for precise orbit determination (POD) and atmospheric sounding. The IGOR is of vital importance for the TanDEM-X mission objectives as the millimeter level determination of the baseline or distance between the two spacecrafts is needed to derive meter level accurate DEMs. Within the TanDEM-X ground segment GFZ is responsible for the operational provision of precise baselines. For this GFZ uses two software chains, first its Earth Parameter and Orbit System (EPOS) software and second the BERNESE software, for backup purposes and quality control. In a concerted effort also the German Aerospace Center (DLR) generates precise baselines independently with a dedicated Kalman filter approach realized in its FRNS software. By the example of GRACE the generation of baselines with millimeter accuracy from on-board GPS data can be validated directly by way of comparing them to the intersatellite K-band range measurements. The K-band ranges are accurate down to the micrometer-level and therefore may be considered as truth. Both TanDEM-X baseline providers are able to generate GRACE baselines with sub-millimeter accuracy. By merging the independent baselines by GFZ and DLR, the accuracy can even be increased. The K-band validation however covers solely the along-track component as the K-band data measure just the distance between the two GRACE satellites. In addition they inhibit an un-known bias which must be modelled in the comparison, so the

  8. Mapping of the gracile axonal dystrophy (gad) gene to a region between D5Mit197 and D5Mit113 on proximal mouse chromosome 5

    SciTech Connect

    Suh, J.G.; Yamanishi, T.; Matsui, K.

    1995-06-10

    The gracile axonal dystrophy (gad) mouse, which shows hereditary sensory ataxia and motor paresis, has been morphologically characterized by the dying back type of axonal degeneration in the nerve terminals of dorsal root ganglion cells and motor neurons. In the present study, using an intraspecific backcross between gad and C57BL/6J mice, the gracile axonal dystrophy (gad) gene was mapped to a region between D5Mit197 and D5Mit113. Estimated distances between gad and D5Mit197 and between gad and D5Mit113 are 0.4 {plus_minus} 0.3 and 5.0 {plus_minus} 1.0 cM, respectively. The gene order was defined: centromere-D5Mit81-D5Mit233-D5Mit184/D5Mit254-D5Mit256-D5Mit197-gad-D5Mit113-D5Mit7. The mouse map location of the gad locus appears to be in a region homologous to human 4p15-p16. Our present data suggest that the nearest flanking marker D5Mit197 provides a useful anchor for the isolation of the gad gene in a yeast artificial chromosome contig. 19 refs., 2 figs.

  9. MIT ASTROMAG 1.7 meter disk magnet design report

    NASA Technical Reports Server (NTRS)

    Marston, P. G.; Hale, J. R.; Vieira, R.; Zhukovsky, A.; Titus, P. H.; Sullivan, J. D.; Dawson, A. M.

    1990-01-01

    MIT has proposed a magnet design for ASTROMAG, which has demonstrated substantial improvement in performance as compared with the present HEAO baseline design. Several advantages of the MIT disk design are listed along with design characteristics. Details of field contours and active field regions are shown along with comparisons with other designs. Three alternative design configurations for the ASTROMAG disk coils are summarized. The parameters of the conductors are listed and basic parameters for each of the complete systems are shown.

  10. Supply Chain Management (SCM) mit Kanban

    NASA Astrophysics Data System (ADS)

    Beer, Anja; Dickmann, Eva; Dickmann, Philipp; Gerth, Wolf-Michael; Graßy, Mario; Herron, Colin; Schmidt, Peter; Seidl, Florian; Wittmann, Claus-Eduard

    Nach Schätzungen von Mercer Management Consulting und dem Fraunhofer Institut wird der Wertschöpfungsanteil in der Automobilindustrie von durchschnittlich 35 % im Jahr 2002 auf 23 % im Jahr 2015 sinken [Merc 04]. Der Trend, die Produktionstiefe oder allgemeiner, die Wertschöpfungstiefe, zu reduzieren, hat zur Folge, dass die Kaufteile den größeren Teil der Wertschöpfung einnehmen. Die Optimierungspotentiale und der Einfluss auf die Kosten wandern immer mehr zu den Lieferanten, vor allem bei größeren Unternehmen oder Konzernen. Lieferanten-Philosophien, die auf oberflächlichen Verbindungen zu Lieferanten aufbauen, um immer optimal und schnell den günstigsten Teilepreis zu erhalten, haben sich in vielen Sparten oder Produktbereichen, z. B. im Maschinenbau, im besten Fall als kurzfristig erfolgreich erwiesen. Kooperative und nachhaltige Strategien sind der erfolgversprechendere Weg, zumindest mittelbis langfristig. In der Realität wird sehr wenig in Supply Chain-Konzepte investiert und die Umsetzungen sind daher vielmals oberflächlich.

  11. Spatial Characterization of Landscapes through Multifractal Analysis of DEM

    PubMed Central

    Aguado, P. L.; Del Monte, J. P.; Moratiel, R.; Tarquis, A. M.

    2014-01-01

    Landscape evolution is driven by abiotic, biotic, and anthropic factors. The interactions among these factors and their influence at different scales create a complex dynamic. Landscapes have been shown to exhibit numerous scaling laws, from Horton's laws to more sophisticated scaling of heights in topography and river network topology. This scaling and multiscaling analysis has the potential to characterise the landscape in terms of the statistical signature of the measure selected. The study zone is a matrix obtained from a digital elevation model (DEM) (map 10 × 10 m, and height 1 m) that corresponds to homogeneous region with respect to soil characteristics and climatology known as “Monte El Pardo” although the water level of a reservoir and the topography play a main role on its organization and evolution. We have investigated whether the multifractal analysis of a DEM shows common features that can be used to reveal the underlying patterns and information associated with the landscape of the DEM mapping and studied the influence of the water level of the reservoir on the applied analysis. The results show that the use of the multifractal approach with mean absolute gradient data is a useful tool for analysing the topography represented by the DEM. PMID:25177728

  12. DEM-based research on the landform features of China

    NASA Astrophysics Data System (ADS)

    Tang, Guoan; Liu, Aili; Li, Fayuan; Zhou, Jieyu

    2006-10-01

    Landforms can be described and identified by parameterization of digital elevation model (DEM). This paper discusses the large-scale geomorphological characteristics of China based on numerical analysis of terrain parameters and develop a methodology for characterizing landforms from DEMs. The methodology is implemented as a two-step process. First, terrain variables are derived from a 1-km DEM in a given statistical unit including local relief, the earth's surface incision, elevation variance coefficient, roughness, mean slope and mean elevation. Second, every parameter regarded as a single-band image is combined into a multi-band image. Then ISODATA unsupervised classification and the Bayesian technique of Maximum Likelihood supervised classification are applied for landform classification. The resulting landforms are evaluated by the means of Stratified Sampling with respect to an existing map and the overall classification accuracy reaches to rather high value. It's shown that the derived parameters carry sufficient physiographic information and can be used for landform classification. Since the classification method integrates manifold terrain indexes, conquers the limitation of the subjective cognition, as well as a low cost, apparently it could represent an applied foreground in the classification of macroscopic relief forms. Furthermore, it exhibits significance in consummating the theory and the methodology of DEMs on digital terrain analysis.

  13. Artificial terraced field extraction based on high resolution DEMs

    NASA Astrophysics Data System (ADS)

    Na, Jiaming; Yang, Xin; Xiong, Liyang; Tang, Guoan

    2017-04-01

    With the increase of human activities, artificial landforms become one of the main terrain features with special geographical and hydrological value. Terraced field, as the most important artificial landscapes of the loess plateau, plays an important role in conserving soil and water. With the development of digital terrain analysis (DTA), there is a current and future need in developing a robust, repeatable and cost-effective research methodology for terraced fields. In this paper, a novel method using bidirectional DEM shaded relief is proposed for terraced field identification based on high resolution DEM, taking Zhifanggou watershed, Shannxi province as the study area. Firstly, 1m DEM is obtained by low altitude aerial photogrammetry using Unmanned Aerial Vehicle (UAV), and 0.1m DOM is also obtained as the test data. Then, the positive and negative terrain segmentation is done to acquire the area of terraced field. Finally, a bidirectional DEM shaded relief is simulated to extract the ridges of each terraced field stages. The method in this paper can get not only polygon feature of the terraced field areas but also line feature of terraced field ridges. The accuracy is 89.7% compared with the artificial interpretation result from DOM. And additional experiment shows that this method has a strong robustness as well as high accuracy.

  14. Improved Fluvial Geomorphic Interpretation Derived From DEM Differencing

    NASA Astrophysics Data System (ADS)

    Wheaton, J. M.; Brasington, J.; Brewer, P. A.; Darby, S.; Pasternack, G. B.; Sear, D.; Vericat, D.; Williams, R.

    2007-12-01

    Technological advances over the past two decades in remotely-sensed and ground-based topographic surveying technologies have made the rapid acquisition of topographic data in the fluvial environment possible at spatial resolutions and extents previously unimaginable. Consequently, monitoring geomorphic changes and estimating fluvial sediment budgets through comparing repeat topographic surveys (DEM differencing) has now become a tractable, affordable approach for both research purposes and long-term monitoring associated with river restoration. However, meaningful quantitative geomorphic interpretation of repeat topographic surveys has received little attention from either researchers or practitioners. Previous research has shown that quantitative estimates of erosion and deposition from DEM differencing are highly sensitive to DEM uncertainty, with minimum level of detection techniques typically discarding between 40% and 90% of the predicted changes. A series of new methods for segregating reach-scale sediment budgets into their specific process components, while accounting for the influence of DEM uncertainty, were developed and explored to highlight distinctive geomorphic signatures between different styles of change. To illustrate the interpretive power of the techniques in different settings, results are presented from analyses across a range of gravel-bed river types: a) the braided River Feshie, Scotland, UK; b) the formerly gravel-mined, wandering Sulphur Creek, California, USA; c) a heavily regulated reach of the Mokelumne River, California, USA that has been subjected to over 5 years of spawning habitat rehabilitation; and d) a restored meandering channel and floodplain of the Highland Water, New Forest, UK. Despite fundamentally different process suites between the study sites, the budget segregation technique is in each case able to aid in more reliable and meaningful geomorphic interpretations of DEM differences.

  15. DEM generated from InSAR in mountainous terrain and its accuracy analysis

    NASA Astrophysics Data System (ADS)

    Hu, Hongbing; Zhan, Yulan

    2011-02-01

    Digital Elevation Model (DEM) derived from survey data is accurate but it is very expensive and time-consuming. In recent years, remote sensing techniques including Synthetic Apenture Radar Interferometry (InSAR) had been developed as a powerful method to derive high precision DEM, especially in mountainous or deep forest areas. The purpose of this paper is to illustrate the principle of InSAR and show the result of a case study in Gejiu city, Yunnan province, China. The accuracy of DEM derived from InSAR (abbreviation as InSAR-DEM) is also evaluated by comparing it with DEM generated from topographic map at the scale of 1:50000 (abbreviation as TOP-DEM). The result shows that: (1)The general precision of the whole selected area acquired by subtracting InSAR-DEM from TOP-DEM is that the maximum, the minimum, the RMSE, and the mean of difference of the two DEMs are 203m, -188m, 26.9m and 5.7m respectively. (2)The topographic trend represented by the two DEMs is coincident, even though TOP-DEM is finer than InSAR-DEM, especial at the valley. (3) Contour maps with the interval of 100m and 50m converted from InSAR-DEM and TOP-DEM respectively show accordant relief trend. Contour from TOP-DEM is smoother than that of from InSAR-DEM, while Contour from InSAR-DEM has more islands than that of from TOP-DEM.(4) Coherence has great influence on the precision of InSAR-DEM, the precision of low-coherence area approaches 100 m while that of high-coherence area can up to m level. (5) The relief trend of 6 profiles represented by InSAR-DEM and TOP-DEM is accordant with tiny difference in partial minutiae. InSAR-DEM displays hypsographies at relative flat areas including surface of water, which reflects the influence of flat earth on InSAR to a certain extent.

  16. Evaluation of lidar-derived DEMs through terrain analysis and field comparison

    Treesearch

    Cody P. Gillin; Scott W. Bailey; Kevin J. McGuire; Stephen P. Prisley

    2015-01-01

    Topographic analysis of watershed-scale soil and hydrological processes using digital elevation models (DEMs) is commonplace, but most studies have used DEMs of 10 m resolution or coarser. Availability of higher-resolution DEMs created from light detection and ranging (lidar) data is increasing but their suitability for such applications has received little critical...

  17. Constructing DEM from characteristic terrain information using HASM method

    NASA Astrophysics Data System (ADS)

    Song, Dunjiang; Yue, Tianxiang; Du, Zhengping; Wang, Qingguo

    2010-11-01

    In the construction of DEM, terrain features (e.g. valleys or stream lines, ridges, peaks, saddle points) are important for improving DEM accuracy and saw many applications in hydrology, precision agriculture, military trajectory planning, etc. HASM (High Accuracy Surface Modeling) is a method for surface modeling, which is based on the theory of surface. Presently, HASM is only used for scattered point's interpolation. So the work in this paper attempts to construct DEM based on the characteristic terrain information as stream lines and scattered points by HASM method. The course is described as the following steps. Firstly TIN (Triangulated Irregular Network) from the scattered points is generated. Secondly, each segment of the stream lines is well oriented to represent stream lines' flow direction, and a tree data structure (that has parent, children and brothers) is used to represent the whole stream lines' segments. A segment is a curve which does not intersect with other segments. A Water Course Flow (WCF) line is a set of segment lines connected piecewise but without overlapping or repetition, from the most upper reaches to the most lower reaches. From the stream lines' tree data structure, all the possible WCF lines are enumerated, and the start point and end point of each WCF lines is predicted from searching among the TIN. Thirdly, given a cell size, a 2-D matrix for the research region is built, and the values of the cells who were traversed by the stream lines by linear interpolation among each WCF lines. Fourthly, all the valued cells that were passed through by the stream line and that were from the scattered points are gathered as known scattered sampling points, and then HASM is used to construct the final DEM. A case study on the typical landform of plateau of China, KongTong gully of Dongzhi Plateau, Qingyang, Gausu province, is presented. The original data is manually vecterized from scanned maps 1:10,000, includes scattered points, stream lines

  18. Constructing DEM from characteristic terrain information using HASM method

    NASA Astrophysics Data System (ADS)

    Song, Dunjiang; Yue, Tianxiang; Du, Zhengping; Wang, Qingguo

    2009-09-01

    In the construction of DEM, terrain features (e.g. valleys or stream lines, ridges, peaks, saddle points) are important for improving DEM accuracy and saw many applications in hydrology, precision agriculture, military trajectory planning, etc. HASM (High Accuracy Surface Modeling) is a method for surface modeling, which is based on the theory of surface. Presently, HASM is only used for scattered point's interpolation. So the work in this paper attempts to construct DEM based on the characteristic terrain information as stream lines and scattered points by HASM method. The course is described as the following steps. Firstly TIN (Triangulated Irregular Network) from the scattered points is generated. Secondly, each segment of the stream lines is well oriented to represent stream lines' flow direction, and a tree data structure (that has parent, children and brothers) is used to represent the whole stream lines' segments. A segment is a curve which does not intersect with other segments. A Water Course Flow (WCF) line is a set of segment lines connected piecewise but without overlapping or repetition, from the most upper reaches to the most lower reaches. From the stream lines' tree data structure, all the possible WCF lines are enumerated, and the start point and end point of each WCF lines is predicted from searching among the TIN. Thirdly, given a cell size, a 2-D matrix for the research region is built, and the values of the cells who were traversed by the stream lines by linear interpolation among each WCF lines. Fourthly, all the valued cells that were passed through by the stream line and that were from the scattered points are gathered as known scattered sampling points, and then HASM is used to construct the final DEM. A case study on the typical landform of plateau of China, KongTong gully of Dongzhi Plateau, Qingyang, Gausu province, is presented. The original data is manually vecterized from scanned maps 1:10,000, includes scattered points, stream lines

  19. Reconstructing Stellar DEMs from X-ray Spectra

    NASA Astrophysics Data System (ADS)

    Kang, H.; van Dyk, D.; Kashyap, V.; Connors, A.

    2004-08-01

    The temperature distribution of Emission Measure is a powerful tool to characterize and understand the composition and physical structure of stellar coronae. Numerous methods have been proposed in the literature to compute the Differential Emission Measure (DEM) based on line fluxes measured from identifiable lines in high-resolution EUV and X-ray spectra. Here we describe a new and powerful method that we have developed to reconstruct DEMs that improves significantly on previous algorithms and further allows for incorporating atomic data errors into the calculations. Some notable features of our algorithm are: an ability to fit to either a selected subset of lines with measured fluxes or to perform a global fit to all lines over the full wavelength range of the instrument, to fully incorporate line blends, to obtain error bars to determine the significance of features seen in the reconstructed DEM, and to directly incorporate prior information such as atomic line sequences, known atomic data errors, systematic effects due to calibration uncertainties, etc. We use highly structured models to account for the mixing of the ion/temperature specific spectra, the mixing of continuum photons with those from the multitude of spectral lines, instrumental response, the effective area of the instrument, and background contamination. We introduce the statistical framework of data augmentation (e.g., EM algorithms and MCMC samplers), in which we treat photon count in each level of the hierarchical structure as missing data. We implement a multi-scale (wavelet-like) prior distribution to smooth the DEM, which gives us the flexibility to overcome lack of information especially with low count data. In this talk we provide several simulation studies with both high-count and low-count data to evaluate the proposed method. We also provide several DEM reconstruction results of the active star alpha Aur (Capella), and validate the method by comparing our results to previous estimates

  20. Application of TanDEM-X interferometry in volcano monitoring

    NASA Astrophysics Data System (ADS)

    Kubanek, Julia; Westerhaus, Malte; Heck, Bernhard

    2013-04-01

    Traditional repeat-pass SAR interferometry (InSAR) has proven to be useful to monitor deformations at active volcanoes. In this so called monostatic mode, images recorded during different satellite passes from slightly changing antenna positions are used to map topographic changes of the earth surface on centimeter scale. However, problems regarding changing atmospheric conditions between the different satellite passes influence the quality of the results. Moreover, the backscattering conditions between two passes need to be tolerably stable to be used for interferometry. As far as the changes in the volcanic environment are slow, repeat-pass InSAR is a great monitoring tool. However, fast changing backscattering conditions result in low coherency, making a classical interferometric deformation analysis impossible. Especially dome-building volcanoes can change on meter scale per second in active phases, preventing the observation with repeat-pass InSAR. To solve these problems, we are currently testing the ability of the German TanDEM-X mission to monitor large deformations at active volcanos. The bistatic TanDEM-X mission consists of two radar satellites (TerraSAR-X and TanDEM-X) flying in a close formation, taking images of the earth surface at the same time. In contrast to the repeat pass mode, this results in two nearly absolutely coherent images, which means that there are no atmospheric disturbances and backscattering errors in the interferometric pair. This allows generating digital elevation models (DEMs) at several times. A simple time series analysis of the models enables for the first time to quantify large topographic changes at active dome-building volcanoes. We chose Volcán de Colima, Mexico as test site. While being a dome building volcano, phases of quiescence are interrupted every few years by dome collapses, pyroclastic flows and deposition of volcanic material. At present, Volcán de Colima seems to be stable. Nevertheless, an explosion at the

  1. Improving the TanDEM-X DEM for flood modelling using flood extents from Synthetic Aperture Radar images.

    NASA Astrophysics Data System (ADS)

    Mason, David; Trigg, Mark; Garcia-Pintado, Javier; Cloke, Hannah; Neal, Jeffrey; Bates, Paul

    2015-04-01

    Many floodplains in the developed world have now been imaged with high resolution airborne LiDAR or InSAR, giving accurate DEMs that facilitate accurate flood inundation modelling. This is not always the case for remote rivers in developing countries. However, the accuracy of DEMs produced for modelling studies on such rivers should be enhanced in the near future by the high resolution TanDEM-X World DEM. In a parallel development, increasing use is now being made of flood extents derived from high resolution SAR images for calibrating, validating and assimilating observations into flood inundation models in order to improve these. The paper discusses an additional use of SAR flood extents to improve the accuracy of the TanDEM-X DEM in the floodplain covered by the flood extents, thereby permanently improving the DEM for future flood modelling studies in this area. The method is based on the fact that for larger rivers the water elevation changes only slowly along a reach, so that the boundary of the flood extent (the waterline) can be regarded locally as a quasi-contour. As a result, heights of adjacent pixels along a small section of waterline can be regarded as a sample of heights with a common population mean. The height of the central pixel in the section can be replaced with the average of these heights, leading to a more accurate height estimate. While this will result in a reduction in the height errors along a waterline, the waterline is a linear feature in a two-dimensional space. However, improvements to the DEM heights between adjacent pairs of waterlines can also be made, because DEM heights enclosed by the higher waterline of a pair must be at least no higher than the refined heights along the higher waterline, whereas DEM heights not enclosed by the lower waterline must be no lower than the refined heights along the lower waterline. In addition, DEM heights between the higher and lower waterlines can also be assigned smaller errors because of the

  2. Poisson disk sampling in geodesic metric for DEM simplification

    NASA Astrophysics Data System (ADS)

    Hou, Wenguang; Zhang, Xuming; Li, Xin; Lai, Xudong; Ding, Mingyue

    2013-08-01

    To generate highly compressed digital elevation models (DEMs) with fine details, the method of Poisson disk sampling in geodesic metric is proposed. The main idea is to uniformly pick points from DEM nodes in geodesic metric, resulting in terrain-adaptive samples in Euclidean metric. This method randomly selects point from mesh nodes and then judges whether this point can be accepted in accordance with the related geodesic distances from the sampled points. The whole process is repeated until no more points can be selected. To further adjust the sampling ratios in different areas, weighted geodesic distance, which is in relation to terrain characteristics, are introduced. In addition to adaptability, sample distributions are well visualised. This method is simple and easy to implement. Cases are provided to illustrate the feasibility and superiority of the proposed method.

  3. Incorporating Atomic Data Errors in Stellar DEM Reconstruction

    NASA Astrophysics Data System (ADS)

    Kang, Hosung; van Dyk, David A.; Kashyap, Vinay L.; Connors, Alanna

    2005-06-01

    We develop a powerful new method to reconstruct stellar Differential Emission Measures (DEMs) its Bayesian framework allows us to incorporate atomic and calibration errors as prior information. For instance, known errors in the line locations, as well as lines missing from the atomic data base, can be included directly during fitting. Highly correlated systematic errors in the ion balance may be included as well, as a natural sequence during Monte Carlo sampling. Our method uses the statistical framework of data augmentation, where we treat photon counts in each level of a hierarchical structure as missing data. We demonstrate our method by fitting a selected subset of emission lines and continuum in Chandra and EUVE data of Capella to estimate the DEM that best describes the data, and simultaneously determine the element abundances. The Markov Chain Monte Carlo based method also naturally produces error estimates on the fit parameters.

  4. The Shuttle Radar Topography Mission: A Global DEM

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Kobrick, Mike

    2000-01-01

    Digital topographic data are critical for a variety of civilian, commercial, and military applications. Scientists use Digital Elevation Models (DEM) to map drainage patterns and ecosystems, and to monitor land surface changes over time. The mountain-building effects of tectonics and the climatic effects of erosion can also be modeled with DEW The data's military applications include mission planning and rehearsal, modeling and simulation. Commercial applications include determining locations for cellular phone towers, enhanced ground proximity warning systems for aircraft, and improved maps for backpackers. The Shuttle Radar Topography Mission (SRTM) (Fig. 1), is a cooperative project between NASA and the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense. The mission is designed to use a single-pass radar interferometer to produce a digital elevation model of the Earth's land surface between about 60 degrees north and south latitude. The DEM will have 30 m pixel spacing and about 15 m vertical errors.

  5. Development of parallel DEM for the open source code MFIX

    SciTech Connect

    Gopalakrishnan, Pradeep; Tafti, Danesh

    2013-02-01

    The paper presents the development of a parallel Discrete Element Method (DEM) solver for the open source code, Multiphase Flow with Interphase eXchange (MFIX) based on the domain decomposition method. The performance of the code was evaluated by simulating a bubbling fluidized bed with 2.5 million particles. The DEM solver shows strong scalability up to 256 processors with an efficiency of 81%. Further, to analyze weak scaling, the static height of the fluidized bed was increased to hold 5 and 10 million particles. The results show that global communication cost increases with problem size while the computational cost remains constant. Further, the effects of static bed height on the bubble hydrodynamics and mixing characteristics are analyzed.

  6. Separability of soils in a tallgrass prairie using SPOT and DEM data

    NASA Technical Reports Server (NTRS)

    Su, Haiping; Ransom, Michel D.; Yang, Shie-Shien; Kanemasu, Edward T.

    1990-01-01

    An investigation is conducted which uses a canonical transformation technique to reduce the features from SPOT and DEM data and evaluates the statistical separability of several prairie soils from the canonically transformed variables. Both SPOT and DEM data was gathered for a tallgrass prairie near Manhattan, Kansas, and high resolution SPOT satellite images were integrated with DEM data. Two canonical variables derived from training samples were selected and it is suggested that canonically transformed data were superior to combined SPOT and DEM data. High resolution SPOT images and DEM data can be used to aid second-order soil surveys in grasslands.

  7. Effect of DEM mesh size on AnnAGNPS simulation and slope correction.

    PubMed

    Wang, Xiaoyan; Lin, Q

    2011-08-01

    The objective of this paper is to study the impact of the mesh size of the digital elevation model (DEM) on terrain attributes within an Annualized AGricultural NonPoint Source pollution (AnnAGNPS) Model simulation at watershed scale and provide a correction of slope gradient for low resolution DEMs. The effect of different grid sizes of DEMs on terrain attributes was examined by comparing eight DEMs (30, 40, 50, 60, 70, 80, 90, and 100 m). The accuracy of the AnnAGNPS stimulation on runoff, sediments, and nutrient loads is evaluated. The results are as follows: (1) Rnoff does not vary much with decrease of DEM resolution whereas soil erosion and total nitrogen (TN) load change prominently. There is little effect on runoff simulation of AnnAGNPS modeling by the amended slope using an adjusted 50 m DEM. (2) A decrease of sediment yield and TN load is observed with an increase of DEM mesh size from 30 to 60 m; a slight decrease of sediment and TN load with the DEM mesh size bigger than 60 m. There is similar trend for total phosphorus (TP) variation, but with less range of variation, the simulation of sediment, TN, and TP increase, in which sediment increase up to 1.75 times compared to the model using unadjusted 50 m DEM. In all, the amended simulation still has a large difference relative to the results using 30 m DEM. AnnAGNPS is less reliable for sediment loading prediction in a small hilly watershed. (3) Resolution of DEM has significant impact on slope gradient. The average, minimum, maximum of slope from the various DEMs reduced obviously with the decrease of DEM precision. For the grade of 0∼15°, the slopes at lower resolution DEM are generally bigger than those at higher resolution DEM. But for the grade bigger than 15°, the slopes at lower resolution DEM are generally smaller than those at higher resolution DEM. So it is necessary to adjust the slope with a fitting equation. A cubic model is used for correction of slope gradient from lower resolution to

  8. Development of a 'bare-earth' SRTM DEM product

    NASA Astrophysics Data System (ADS)

    O'Loughlin, Fiachra; Paiva, Rodrigo; Durand, Michael; Alsdorf, Douglas; Bates, Paul

    2015-04-01

    We present the methodology and results from the development of a near-global 'bare-earth' Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM) data. Digital Elevation Models are the most important input for hydraulic modelling, as the DEM quality governs the accuracy of the model outputs. While SRTM is currently the best near-globally [60N to 60S] available DEM, it requires adjustments to reduce the vegetation contamination and make it useful for hydrodynamic modelling over heavily vegetated areas (e.g. tropical wetlands). Unlike previous methods of accounting for vegetation contamination, which concentrated on correcting relatively small areas and usually applied a static adjustment, we account for vegetation contamination globally and apply a spatial varying correction, based on information about canopy height and density. In creating the final 'bare-earth' SRTM DEM dataset, we produced three different 'bare-earth' SRTM products. The first applies global parameters, while the second and third products apply parameters that are regionalised based on either climatic zones or vegetation types, respectively. We also tested two different canopy density proxies of different spatial resolution. Using ground elevations obtained from the ICESat GLA14 satellite altimeter, we calculate the residual errors for the raw SRTM and the three 'bare-earth' SRTM products and compare performances. The three 'bare-earth' products all show large improvements over the raw SRTM in vegetated areas with the overall mean bias reduced by between 75 and 92% from 4.94 m to 0.40 m. The overall standard deviation is reduced by between 29 and 33 % from 7.12 m to 4.80 m. As expected, improvements are higher in areas with denser vegetation. The final 'bare-earth' SRTM dataset is available at 3 arc-second with lower vertical height errors and less noise than the original SRTM product.

  9. BOREAS Regional DEM in Raster Format and AEAC Projection

    NASA Technical Reports Server (NTRS)

    Knapp, David; Verdin, Kristine; Hall, Forrest G. (Editor)

    2000-01-01

    This data set is based on the GTOPO30 Digital Elevation Model (DEM) produced by the United States Geological Survey EROS Data Center (USGS EDC). The BOReal Ecosystem-Atmosphere Study (BOREAS) region (1,000 km x 1000 km) was extracted from the GTOPO30 data and reprojected by BOREAS staff into the Albers Equal-Area Conic (AEAC) projection. The pixel size of these data is 1 km. The data are stored in binary, image format files.

  10. Mapping debris-flow hazard in Honolulu using a DEM

    USGS Publications Warehouse

    Ellen, Stephen D.; Mark, Robert K.; ,

    1993-01-01

    A method for mapping hazard posed by debris flows has been developed and applied to an area near Honolulu, Hawaii. The method uses studies of past debris flows to characterize sites of initiation, volume at initiation, and volume-change behavior during flow. Digital simulations of debris flows based on these characteristics are then routed through a digital elevation model (DEM) to estimate degree of hazard over the area.

  11. Designing Tunnel Support in Jointed Rock Masses Via the DEM

    NASA Astrophysics Data System (ADS)

    Boon, C. W.; Houlsby, G. T.; Utili, S.

    2015-03-01

    A systematic approach of using the distinct element method (DEM) to provide useful insights for tunnel support in moderately jointed rock masses is illustrated. This is preceded by a systematic study of common failure patterns for unsupported openings in a rock mass intersected by three independent sets of joints. The results of our simulations show that a qualitative description of the failure patterns using specific descriptors is unattainable. Then, it is shown that DEM analyses can be employed in the preliminary design phase of tunnel supports to determine the main parameters of a support consisting of rock bolts or one lining or a combination of both. A comprehensive parametric analysis investigating the effect of bolt bonded length, bolt spacing, bolt length, bolt pretension, bolt stiffness and lining thickness on the tunnel convergence is illustrated. The highlight of the proposed approach of preliminary support design is the use of a rock bolt and lining interaction diagram to evaluate the relative effectiveness of rock bolts and lining thickness in the design of the tunnel support. The concept of interaction diagram can be used to assist the engineer in making preliminary design decisions given a target maximum allowable convergence. In addition, DEM simulations were validated against available elastic solutions. To the authors' knowledge, this is the first verification of DEM calculations for supported openings against elastic solutions. The methodologies presented in this article are illustrated through 2-D plane strain analyses for the preliminary design stage. More rigorous analyses incorporating 3-D effects have not been attempted in this article because the longitudinal displacement profile is highly sensitive to the joint orientations with respect to the tunnel axis, and cannot be established accurately in 2-D. The methodologies and concepts discussed in this article, however, have the potential to be extended to 3-D analyses.

  12. DEM Simulation of Rotational Disruption of Rubble-Pile Asteroids

    NASA Astrophysics Data System (ADS)

    Sanchez, Paul; Scheeres, D. J.

    2010-10-01

    We report on our study of rotation induced disruption of a self-gravitating granular aggregate by using a Discrete Element Method (DEM) granular dynamics code, a class of simulation commonly used in the granular mechanics community. Specifically, we simulate the behavior of a computer simulated asteroid when subjected to an array of rotation rates that cross its disruption limit. The code used to carry out these studies implements a Soft-sphere DEM method as applied for granular systems. In addition a novel algorithm to calculate self-gravitating forces which makes use of the DEM static grid has been developed and implemented in the code. By using a DEM code, it is possible to model a poly-disperse aggregate with a specified size distribution power law, incorporate contact forces such as dry cohesion and friction, and compute internal stresses within the gravitational aggregate. This approach to the modeling of gravitational aggregates is complementary to and distinctly different than other approaches reported in the literature. The simulations use both 2D and 3D modeling for analysis. One aim of this work is to understand the basic processes and dynamics of aggregates during the disruption process. We have used these simulations to understand how to form a contact binary that mimics observed asteroid shapes, how to accelerate the rotation rate of the aggregate so that it has enough time to reshape and find a stable configuration and how to analyze a system that has an occasionally changing shape. From a more physical point of view, we have focused on the understanding of the dynamics of the reshaping process, the evolution of internal stresses during this reshaping and finding the critical disruption angular velocity. This research was supported by a grant from NASA's PG&G Program: NNX10AJ66G

  13. DEM analysis of FOXSI-2 microflare using AIA observations

    NASA Astrophysics Data System (ADS)

    Athiray Panchapakesan, Subramania; Glesener, Lindsay; Vievering, Juliana; Camilo Buitrago-Casas, Juan; Christe, Steven; Inglis, Andrew; Krucker, Sam; Musset, Sophie

    2017-08-01

    The second flight of Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment was successfully completed on 11 December 2014. FOXSI makes direct imaging and spectral observation of the Sun in hard X-rays using grazing incidence optics modules which focus X-rays onto seven focal plane detectors kept at a 2m distance, in the energy range 4 to 20 keV, to study particle acceleration and coronal heating. Significant HXR emissions were observed by FOXSI during microflare events with A0.5 and A2.5 class, as classified by GOES, that occurred during FOXSI-2 flight.Spectral analysis of FOXSI data for these events indicate presence of plasma at higher temperatures (>10MK). We attempt to study the plasma content in the corona at different temperatures, characterized by the differential emission measure (DEM), over the FOXSI-2 observed flare regions using the Atmospheric Imaging Assembly (SDO/AIA) data. We utilize AIA observations in different EUV filters that are sensitive to ionized iron lines, to determine the DEM by using a regularized inversion method. This poster will show the properties of hot plasma as derived from FOXSI-2 HXR spectra with supporting DEM analysis using AIA observations.

  14. A simplified DEM numerical simulation of vibroflotation without backfill

    NASA Astrophysics Data System (ADS)

    Jiang, M. J.; Liu, W. W.; He, J.; Sun, Y.

    2015-09-01

    Vibroflotation is one of the deep vibratory compaction techniques for ground reinforcement. This method densities the soil and improves its mechanical properties, thus helps to protect people's lives and property from geological disasters. The macro reinforcement mechanisms of vibroflotation method have been investigated by numerical simulations, laboratory and in-situ experiments. However, little attention has been paid on its micro - mechanism, which is essential to fully understand the principle of the ground reinforcement. Discrete element method (DEM), based on discrete mechanics, is more powerful to solve large deformation and failure problems. This paper investigated the macro-micro mechanism of vibroflotation without backfill under two conditions, i.e., whether or not the ground water was considered, by incorporating inter-particle rolling resistance model in the DEM simulations. Conclusions obtained are as follows: The DEM simulations incorporating rolling resistance well replicate the mechanical response of the soil assemblages and are in line with practical observations. The void ratio of the granular soil fluctuates up and down in the process of vibroflotation, and finally reduces to a lower value. It is more efficient to densify the ground without water compared to the ground with water.

  15. Siku DEM Simulations of Beaufort Sea-Ice Fracture Pattern.

    NASA Astrophysics Data System (ADS)

    Kulchitsky, A. V.; Hutchings, J. K.; Johnson, J.; Velikhovskiy, G.

    2016-12-01

    Leads are fractures in the ice pack where exposed ocean surface increases heat and moisture fluxes to the atmosphere. These leads are the location of shear in the pack and during winter control the transport of ice around the Beaufort Gyre. Hence prediction of lead direction opening and shear is important in forecasting sea ice drift and weather. Regional ice pack deformation is related to the fracture patterns, and related shear zones. Hence climate models need to simulate these processes to simulate realistic sea-ice transport and mass balance. We have developed a new discrete element method (DEM) model of sea ice, Siku, to forecast lead patterns. Siku is the first sea ice DEM model that takes into account the spherical geometry of the Earth, and allows simulation ranging from basin scale to meter scale without nesting. We present simulations with 2.5km resolution in the Chukchi and Beaufort Seas, and 25-100km across the rest of the Arctic. The DEM has been shown to reproduce discontinuous dynamics that result in shear patterns in the ice cover. We evaluate these against observed fracture patterns in thermal band satellite imagery. Simulations with differing ice mechanics produce lead pattern differences that are used to evaluate the physical validity of proposed physics of ice-ice and ice-coast contact. We present simulations demonstrating a good match to observations and discuss the implications for continuum modeling, where predicted ice transport along the Alaskan coast is known to be too slow.

  16. Efficient parallel CFD-DEM simulations using OpenMP

    NASA Astrophysics Data System (ADS)

    Amritkar, Amit; Deb, Surya; Tafti, Danesh

    2014-01-01

    The paper describes parallelization strategies for the Discrete Element Method (DEM) used for simulating dense particulate systems coupled to Computational Fluid Dynamics (CFD). While the field equations of CFD are best parallelized by spatial domain decomposition techniques, the N-body particulate phase is best parallelized over the number of particles. When the two are coupled together, both modes are needed for efficient parallelization. It is shown that under these requirements, OpenMP thread based parallelization has advantages over MPI processes. Two representative examples, fairly typical of dense fluid-particulate systems are investigated, including the validation of the DEM-CFD and thermal-DEM implementation with experiments. Fluidized bed calculations are performed on beds with uniform particle loading, parallelized with MPI and OpenMP. It is shown that as the number of processing cores and the number of particles increase, the communication overhead of building ghost particle lists at processor boundaries dominates time to solution, and OpenMP which does not require this step is about twice as fast as MPI. In rotary kiln heat transfer calculations, which are characterized by spatially non-uniform particle distributions, the low overhead of switching the parallelization mode in OpenMP eliminates the load imbalances, but introduces increased overheads in fetching non-local data. In spite of this, it is shown that OpenMP is between 50-90% faster than MPI.

  17. Interpolation and elevation errors: the impact of the DEM resolution

    NASA Astrophysics Data System (ADS)

    Achilleos, Georgios A.

    2015-06-01

    Digital Elevation Models (DEMs) are developing and evolving at a fast pace, given the progress of computer science and technology. This development though, is not accompanied by an advancement of knowledge on the quality of the models and their indigenous inaccuracy. The user on most occasions is not aware of this quality thus in not aware of the correlating product uncertainty. Extensive research has been conducted - and still is - towards this direction. In the research presented in this paper there is an analysis of elevation errors behavior which are recorded in a DEM. The behavior of these elevation errors, is caused by altering the DEM resolution upon the application of the algorithm interpolation. Contour lines are used as entry data from a topographical map. Elevation errors are calculated in the positions of the initial entry data and wherever the elevation is known. The elevation errors that are recorded, are analyzed, in order to reach conclusions about their distribution and the way in which they occur.

  18. Towards the Optimal Pixel Size of dem for Automatic Mapping of Landslide Areas

    NASA Astrophysics Data System (ADS)

    Pawłuszek, K.; Borkowski, A.; Tarolli, P.

    2017-05-01

    Determining appropriate spatial resolution of digital elevation model (DEM) is a key step for effective landslide analysis based on remote sensing data. Several studies demonstrated that choosing the finest DEM resolution is not always the best solution. Various DEM resolutions can be applicable for diverse landslide applications. Thus, this study aims to assess the influence of special resolution on automatic landslide mapping. Pixel-based approach using parametric and non-parametric classification methods, namely feed forward neural network (FFNN) and maximum likelihood classification (ML), were applied in this study. Additionally, this allowed to determine the impact of used classification method for selection of DEM resolution. Landslide affected areas were mapped based on four DEMs generated at 1 m, 2 m, 5 m and 10 m spatial resolution from airborne laser scanning (ALS) data. The performance of the landslide mapping was then evaluated by applying landslide inventory map and computation of confusion matrix. The results of this study suggests that the finest scale of DEM is not always the best fit, however working at 1 m DEM resolution on micro-topography scale, can show different results. The best performance was found at 5 m DEM-resolution for FFNN and 1 m DEM resolution for results. The best performance was found to be using 5 m DEM-resolution for FFNN and 1 m DEM resolution for ML classification.

  19. A Global Corrected SRTM DEM Product Over Vegetated Areas Using LiDAR Data

    NASA Astrophysics Data System (ADS)

    Zhao, X.; Guo, Q.; Su, Y.; Hu, T.

    2016-12-01

    The Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) is one of the most complete and frequently used global-scale DEM products in various applications. However, previous studies have shown that the SRTM DEM is systematically higher than the actual land surface in vegetated mountain areas. The objective of this study is to propose a procedure to calibrate the SRTM DEM over global vegetated mountain areas. To address this, we firstly collected airborne LiDAR data over 200,000 km2 globally used as ground truth data to analyze the uncertainty of the SRTM DEM. The Geoscience Laser Altimeter System (GLAS)/ICESat (Ice, Cloud, and land Elevation Satellite) data were used as complementary data in areas lack of airborne LiDAR data. Secondly, we modelled the SRTM DEM error for each vegetation type using regression methods. Tree height, canopy cover, and terrain slope were used as dependent variables to model the SRTM DEM error. Finally, these regression models were used to estimate the SRTM DEM error in vegetated mountain areas without LiDAR data coverage, and therefore correct the SRTM DEM. Our results show that the new corrected SRTM DEM can significantly reduce the systematic bias of the SRTM DEM in vegetated mountain areas.

  20. The US DOE/MIT Innovation Acceleration Competition

    SciTech Connect

    None, None

    2009-06-30

    The Competition asked student teams from several US Universities to propose business models, technological systems, and policy framework to accelerate the penetration of new vehicle and fuel technologies into the markets. In May 2009 the final selection of teams was announced and four of five finalist teams flew to Washington DC to present to the US Department of Energy. The five finalist teams were 1. Filter Sensing Technologies (FST) (MIT), 2. Flex Cathode Technology for Electric Vehicle Batteries, 3. Green Guidance (RPI), 4. Levant Power (MIT), and 5. Wind-Driven Paddlewheel Cylinder for Energy Storage in Freighter Trucks (Villanova). The five finalists entries are described.

  1. Effect of DEM Source and Resolution on Extracting River Network and Watershed within Multi-Lake Area in Tibet

    NASA Astrophysics Data System (ADS)

    Li, Yang; Li, Gang; Lin, Hui

    2014-11-01

    DEM defines drainage structures and basin through conducting overland flow simulation. Two matured DEM Sources are SRTM DEM (Shuttle Radar Topographic Mission) and ASTER GDEM (Advanced Space borne Thermal Emission and Reflection Radiometer Global Digital Elevation Model); The accuracy of hydrological characters that derived from DEM decreased from high resolution to coarse resolutionand appeared to be different in different data source.

  2. In need of combined topography and bathymetry DEM

    NASA Astrophysics Data System (ADS)

    Kisimoto, K.; Hilde, T.

    2003-04-01

    In many geoscience applications, digital elevation models (DEMs) are now more commonly used at different scales and greater resolution due to the great advancement in computer technology. Increasing the accuracy/resolution of the model and the coverage of the terrain (global model) has been the goal of users as mapping technology has improved and computers get faster and cheaper. The ETOPO5 (5 arc minutes spatial resolution land and seafloor model), initially developed in 1988 by Margo Edwards, then at Washington University, St. Louis, MO, has been the only global terrain model for a long time, and it is now being replaced by three new topographic and bathymetric DEMs, i.e.; the ETOPO2 (2 arc minutes spatial resolution land and seafloor model), the GTOPO30 land model with a spatial resolution of 30 arc seconds (c.a. 1km at equator) and the 'GEBCO 1-MINUTE GLOBAL BATHYMETRIC GRID' ocean floor model with a spatial resolution of 1 arc minute (c.a. 2 km at equator). These DEMs are products of projects through which compilation and reprocessing of existing and/or new datasets were made to meet user's new requirements. These ongoing efforts are valuable and support should be continued to refine and update these DEMs. On the other hand, a different approach to create a global bathymetric (seafloor) database exists. A method to estimate the seafloor topography from satellite altimetry combined with existing ships' conventional sounding data was devised and a beautiful global seafloor database created and made public by W.H. Smith and D.T. Sandwell in 1997. The big advantage of this database is the uniformity of coverage, i.e. there is no large area where depths are missing. It has a spatial resolution of 2 arc minute. Another important effort is found in making regional, not global, seafloor databases with much finer resolutions in many countries. The Japan Hydrographic Department has compiled and released a 500m-grid topography database around Japan, J-EGG500, in 1999

  3. Local scale validation of the final TanDEM-X DEM in the Lowveld Savanna, South Africa, using highly accurate differential GNSS ground measurements

    NASA Astrophysics Data System (ADS)

    Baade, Jussi; Schmullius, Christiane

    2017-04-01

    Digital Elevation Models (DEM) represent fundamental data for a range of applications including Earth surface process studies in the field of ecology, geology, geomorphology and hydrology, among others. For some countries, high resolution Digital Terrain Models (DTM) representing the solid Earth surface derived from topographic maps or aerial surveys (photogrammetry, LiDAR) are available. But for vast regions of the Earth this fundamental data is missing at a high geometric resolution. From January 2010 to December 2015 the German Space Agency (DLR) TanDEM-X mission acquired data for a new and truly global Digital Elevation Model (DEM). Since October 2016, the final DEM is available in three resolution editions (0.4, 1 and 3 arc sec or 12 m, 30 m and 90 m, respectively). First validation results suggest an accuracy of about 1 m; an order of magnitude higher than the initially targeted benchmark for the linear error (LE90 < 10 m). Due to the lack of other high resolution DEMs in many parts of the World, it is foreseeable, that this DEM will be used as fundamental data not only for global scale, but as well for regional and local scale studies in the near future. Here we present results of a local scale accuracy assessment of the TanDEM-X DEM based on more than 10,000 highly accurate ground measurements (σ < 0.05 m) acquired in a differential Global Navigation Satellite System (dGNSS) survey of fourteen sites across the Kruger National Park, South Africa. The study sites are characterized by moderate terrain and open savanna vegetation providing the opportunity to investigate the accuracy of the new DEM in open terrain. However, the results demonstrate at the same time the sensitivity of the new DEM to canopy cover. A property, geomorphologists need to be aware of.

  4. Research on the method of extracting DEM based on GBInSAR

    NASA Astrophysics Data System (ADS)

    Yue, Jianping; Yue, Shun; Qiu, Zhiwei; Wang, Xueqin; Guo, Leping

    2016-05-01

    Precise topographical information has a very important role in geology, hydrology, natural resources survey and deformation monitoring. The extracting DEM technology based on synthetic aperture radar interferometry (InSAR) obtains the three-dimensional elevation of the target area through the phase information of the radar image data. The technology has large-scale, high-precision, all-weather features. By changing track in the location of the ground radar system up and down, it can form spatial baseline. Then we can achieve the DEM of the target area by acquiring image data from different angles. Three-dimensional laser scanning technology can quickly, efficiently and accurately obtain DEM of target area, which can verify the accuracy of DEM extracted by GBInSAR. But research on GBInSAR in extracting DEM of the target area is a little. For lack of theory and lower accuracy problems in extracting DEM based on GBInSAR now, this article conducted research and analysis on its principle deeply. The article extracted the DEM of the target area, combined with GBInSAR data. Then it compared the DEM obtained by GBInSAR with the DEM obtained by three-dimensional laser scan data and made statistical analysis and normal distribution test. The results showed the DEM obtained by GBInSAR was broadly consistent with the DEM obtained by three-dimensional laser scanning. And its accuracy is high. The difference of both DEM approximately obeys normal distribution. It indicated that extracting the DEM of target area based on GBInSAR is feasible and provided the foundation for the promotion and application of GBInSAR.

  5. MIT Orients Course Materials Online to K-12

    ERIC Educational Resources Information Center

    Cavanagh, Sean

    2008-01-01

    Many science and mathematics educators across the country are taking advantage of a Web site created by the Massachusetts Institute of Technology (MIT), the famed research university located in Cambridge, Massachusetts, which offers free video, audio, and print lectures and course material taken straight from the school's classes. Those resources…

  6. MIT Mints a Valuable New Form of Academic Currency

    ERIC Educational Resources Information Center

    Carey, Kevin

    2012-01-01

    The Massachusetts Institute of Technology (MIT) has invented or improved many world-changing things--radar, information theory, and synthetic self-replicating molecules, to name a few. Last month the university announced, to mild fanfare, an invention that could be similarly transformative, this time for higher education itself. It is called MITx.…

  7. MIT Mints a Valuable New Form of Academic Currency

    ERIC Educational Resources Information Center

    Carey, Kevin

    2012-01-01

    The Massachusetts Institute of Technology (MIT) has invented or improved many world-changing things--radar, information theory, and synthetic self-replicating molecules, to name a few. Last month the university announced, to mild fanfare, an invention that could be similarly transformative, this time for higher education itself. It is called MITx.…

  8. Numerische Berechnung von Wirbelstromproblemen mit der Cell-Methode

    NASA Astrophysics Data System (ADS)

    Frenner, K.; Rucker, W. M.

    2006-09-01

    In dieser Arbeit wird die Cell-Methode auf die quasistatischen Maxwellgleichungen angewendet. Dabei werden für die notwendige Transformation vom Primärgitter auf das duale Gitter reziproke Basisvektoren verwendet. Anhand der Felddiffusion der magnetischen Induktion in einen zylindrischen Leiter werden Ergebnisse der Cell-Methode mit einer analytischen Vergleichsrechnung präsentiert.

  9. The Creation of OpenCourseWare at MIT

    ERIC Educational Resources Information Center

    Abelson, Hal

    2008-01-01

    This paper traces the genesis of the MIT OpenCourseWare project from its initial strategic precursors in 1999 and 2000, through its launch in 2001 and its subsequent evolution. The story told here illuminates the interplay among institutional leadership, and strategic planning, and with university culture in launching major educational technology…

  10. A coupled DEM-CFD method for impulse wave modelling

    NASA Astrophysics Data System (ADS)

    Zhao, Tao; Utili, Stefano; Crosta, GiovanBattista

    2015-04-01

    Rockslides can be characterized by a rapid evolution, up to a possible transition into a rock avalanche, which can be associated with an almost instantaneous collapse and spreading. Different examples are available in the literature, but the Vajont rockslide is quite unique for its morphological and geological characteristics, as well as for the type of evolution and the availability of long term monitoring data. This study advocates the use of a DEM-CFD framework for the modelling of the generation of hydrodynamic waves due to the impact of a rapid moving rockslide or rock-debris avalanche. 3D DEM analyses in plane strain by a coupled DEM-CFD code were performed to simulate the rockslide from its onset to the impact with still water and the subsequent wave generation (Zhao et al., 2014). The physical response predicted is in broad agreement with the available observations. The numerical results are compared to those published in the literature and especially to Crosta et al. (2014). According to our results, the maximum computed run up amounts to ca. 120 m and 170 m for the eastern and western lobe cross sections, respectively. These values are reasonably similar to those recorded during the event (i.e. ca. 130 m and 190 m respectively). In these simulations, the slope mass is considered permeable, such that the toe region of the slope can move submerged in the reservoir and the impulse water wave can also flow back into the slope mass. However, the upscaling of the grains size in the DEM model leads to an unrealistically high hydraulic conductivity of the model, such that only a small amount of water is splashed onto the northern bank of the Vajont valley. The use of high fluid viscosity and coarse grain model has shown the possibility to model more realistically both the slope and wave motions. However, more detailed slope and fluid properties, and the need for computational efficiency should be considered in future research work. This aspect has also been

  11. Retrospektive Analyse von Zufallsbefunden, die bei Patienten mit kutanem malignen Malignom durch (18) F-Fluordeoxyglucose-PET/CT erhoben wurden.

    PubMed

    Conrad, Franziska; Winkens, Thomas; Kaatz, Martin; Goetze, Steven; Freesmeyer, Martin

    2016-08-01

    Bei der (18) F-Fluordeoxyglucose-Positronenemissionstomographie/Computertomographie (FDG-PET/CT) ergeben sich häufig Zufallsbefunde. In der vorliegenden Studie konzentrierten wir uns auf mittels FDG-PET/CT erhaltene Zufallsbefunde bei Patienten mit kutanem Melanom und überprüften deren Relevanz hinsichtlich weiterer diagnostischer Maßnahmen und Interventionen. Die Krankenakten von 181 konsekutiven Melanom-Patienten wurden retrospektiv ausgewertet, um das Management von Zufallsbefunden zu dokumentieren. Der Schwerpunkt lag dabei auf den histologischen Befunden. Bei 33 von 181 (18 %) Patienten lagen 39 relevante Zufallsbefunde vor, und zwar im Kolorektalbereich (n = 15 Patienten), in der Schilddrüse (n = 8), der Prostata (n = 2), dem Bewegungsapparat (n = 2), in Lymphknoten (n = 2), der Parotis (n = 1), den Mandeln (n = 1), den Nieren (n = 1) und der Gallenblase (n = 1). Bei 25 Patienten schlossen sich weitere diagnostische Verfahren an, wobei in 21 Fällen ein klinisches Korrelat nachgewiesen wurde. Bei 16 von 21 Patienten ergab sich eine Neoplasie, darunter fünf maligne Läsionen (vier Kolonkarzinome und ein Prostatakarzinom). Die Malignome wurden frühzeitig diagnostiziert und in der Mehrzahl der Fälle erfolgreich entfernt. Der Einsatz der FDG-PET/CT als Routine-Diagnostik wird in den Leitlinien empfohlen und ist indiziert bei malignem Melanom ab Stadium IIC. In dieser Studie wurden auf effektive Weise ansonsten nicht erkannte Krebserkrankungen, insbesondere Kolonkarzinome, detektiert. In den meisten Fällen war eine frühe Intervention möglich. Zufallsbefunde durch FDG-PET/CT sollten, unter Berücksichtigung des Zustands und der Wünsche des Patienten, mit den geeigneten diagnostischen Maßnahmen abgeklärt werden. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  12. A global database of volcano edifice morphometry using SRTM DEMs

    NASA Astrophysics Data System (ADS)

    Grosse, P.; van Wyk de Vries, B.; Petrinovic, I. A.; Euillades, P. A.

    2009-12-01

    The morphometry of volcanic edifices reflects the aggradational and degradational processes that interact during their evolution. In association with VOGRIPA, a global risk identification project, we are currently constructing a database on the morphometry of volcanic edifices using digital elevation models (DEMs) from the Shuttle Radar Topography Mission (SRTM). Our aim is to compile and make available a global database of morphometric parameters that characterize the shape and size of volcanic edifices. The 90-meter SRTM DEM is presently the best public-access DEM dataset for this task because of its near-global coverage and spatial resolution that is high enough for the analysis of composite volcanic edifices. The Smithsonian Institution database lists 1536 active/potentially active volcanoes worldwide. Of these, ~900 volcano edifices can be analyzed with the SRTM DEMs, discarding volcanoes not covered by the dataset above latitudes 60°N and 56°S, submarine volcanoes, volcanoes with mostly negative topographies (i.e. calderas, maars) and monogenetic cones and domes, which are too small to accurately study with the 90-meter resolution. Morphometric parameters are acquired using an expressly written IDL-language code named MORVOLC. Edifice outline is determined via a semi-automated algorithm that identifies slope-breaks between user-estimated maximum and minimum outlines. Thus, volcanic edifices as topographic entities are considered, excluding aprons or ring plains and other far-reaching volcanic products. Several morphometric parameters are computed which characterize edifice size and shape. Size parameters are height (from base to summit), volume, base and summit areas and widths (average, minimum, maximum). Plan shape is summarized using two independent dimensionless indexes that describe the shape of the elevation contours, ellipticity (quantifies the elongation of each contour) and irregularity (quantifies the irregularity or complexity of each contour

  13. An Overview of the CapDEM Integrated Engineering Environment

    DTIC Science & Technology

    2005-07-01

    cours d’un exercice d’élaboration et d’expérimentation de concepts (EEC) du DIGCap. On utilisera lors de cet exercice d’EEC les mêmes outils pour...utilize the existing IEE. First, the IEE will be used to provide engineering data management for the CapDEM Concept Development and Experimentation (CD...E) exercise. This CD&E exercise will employ the same set of tools to demonstrate the application of capability engineering concepts to support CD&E

  14. Processing, validating, and comparing DEMs for geomorphic application on the Puna de Atacama Plateau, northwest Argentina

    NASA Astrophysics Data System (ADS)

    Purinton, Benjamin; Bookhagen, Bodo

    2016-04-01

    This study analyzes multiple topographic datasets derived from various remote-sensing methods from the Pocitos Basin of the central Puna Plateau in northwest Argentina at the border to Chile. Here, the arid climate and clear atmospheric conditions and lack of vegetation provide ideal conditions for remote sensing and Digital Elevation Model (DEM) comparison. We compare the following freely available DEMs: SRTM-X (spatial resolution of ~30 m), SRTM-C v4.1 (90 m), and ASTER GDEM2 (30 m). Additional DEMs for comparison are generated from optical and radar datasets acquired freely (ASTER Level 1B stereo pairs and Sentinal-1A radar), through research agreements (RapidEye Level 1B scenes, ALOS radar, and ENVISAT radar), and through commercial sources (TerraSAR-X / TanDEM-X radar). DEMs from ASTER (spatial resolution of 15 m) and RapidEye (~5-10 m) optical datasets are produced by standard photogrammetric techniques and have been post-processed for validation and alignment purposes. Because RapidEye scenes are captured at a low incidence angle (<20°) and stereo pairs are unavailable, merging and averaging methods of two to four overlapping scenes is explored for effective DEM generation. Sentinal-1A, TerraSAR-X / TanDEM-X, ALOS, and ENVISAT radar data is processed through interferometry resulting in DEMs with spatial resolutions ranging from 5 to 30 meters. The SRTM-X dataset serves as a control in the creation of further DEMs, as it is widely used in the geosciences and represents the highest-quality DEM currently available. All DEMs are validated against over 400,000 differential GPS (dGPS) measurements gathered during four field campaigns in 2012 and 2014 to 2016. Of these points, more than 250,000 lie within the Pocitos Basin with average vertical and horizontal accuracies of 0.95 m and 0.69 m, respectively. Dataset accuracy is judged by the lowest standard deviations of elevation compared with the dGPS data and with the SRTM-X control DEM. Of particular interest in

  15. High-Precision DEM Generation Using Satellite-Borne InSAR Technology

    NASA Astrophysics Data System (ADS)

    Li, Tao; Tang, Xinming; Gao, Xiaoming; Chen, Weinan; Chen, Qianfu; Wu, Danqin

    2016-08-01

    Satellite-borne InSAR is useful in generating DEM globally. Especially after TanDEM-X interferometer started its mission in 2010. In this paper, we analyze the interferometric geometry in surveying and mapping application. And we locate main error sources, i.e., phase error and baseline error, using the parameters extracted from TanDEM-X interferometer. The phase error is suppressed using multi-look iteration. The rich textures as well as the high phase accuracy are both maintained through this method. The baseline error is reduced by using the long-and-short baseline combination method. Finally, we propose to mosaic the ascending and descending DEM according to coherence values to reduce the low coherent areas. Experiments in flat ground, hill and mountain land are conducted to test the feasibility of the proposed methods. Results demonstrate that TanDEM-X may be used in high-precision DEM generation.

  16. Effects of lidar point density on bare earth extraction and DEM creation

    NASA Astrophysics Data System (ADS)

    Puetz, Angela M.; Olsen, R. Chris; Anderson, Brian

    2009-05-01

    Data density has a crucial impact on the accuracy of Digital Elevation Models (DEMs). In this study, DEMs were created from a high point-density LIDAR dataset using the bare earth extraction module in Quick Terrain Modeler. Lower point-density LIDAR collects were simulated by randomly selecting points from the original dataset at a series of decreasing percentages. The DEMs created from the lower resolution datasets are compared to the original DEM. Results show a decrease in DEM accuracy as the resolution of the LIDAR dataset is reduced. Some analysis is made of the types of errors encountered in the lower resolution DEMs. It is also noted that the percentage of points classified as bare earth decreases as the resolution of the LIDAR dataset is reduced.

  17. The Importance of Precise Digital Elevation Models (DEM) in Modelling Floods

    NASA Astrophysics Data System (ADS)

    Demir, Gokben; Akyurek, Zuhal

    2016-04-01

    Digital elevation Models (DEM) are important inputs for topography for the accurate modelling of floodplain hydrodynamics. Floodplains have a key role as natural retarding pools which attenuate flood waves and suppress flood peaks. GPS, LIDAR and bathymetric surveys are well known surveying methods to acquire topographic data. It is not only time consuming and expensive to obtain topographic data through surveying but also sometimes impossible for remote areas. In this study it is aimed to present the importance of accurate modelling of topography for flood modelling. The flood modelling for Samsun-Terme in Blacksea region of Turkey is done. One of the DEM is obtained from the point observations retrieved from 1/5000 scaled orthophotos and 1/1000 scaled point elevation data from field surveys at x-sections. The river banks are corrected by using the orthophotos and elevation values. This DEM is named as scaled DEM. The other DEM is obtained from bathymetric surveys. 296 538 number of points and the left/right bank slopes were used to construct the DEM having 1 m spatial resolution and this DEM is named as base DEM. Two DEMs were compared by using 27 x-sections. The maximum difference at thalweg of the river bed is 2m and the minimum difference is 20 cm between two DEMs. The channel conveyance capacity in base DEM is larger than the one in scaled DEM and floodplain is modelled in detail in base DEM. MIKE21 with flexible grid is used in 2- dimensional shallow water flow modelling. The model by using two DEMs were calibrated for a flood event (July 9, 2012). The roughness is considered as the calibration parameter. From comparison of input hydrograph at the upstream of the river and output hydrograph at the downstream of the river, the attenuation is obtained as 91% and 84% for the base DEM and scaled DEM, respectively. The time lag in hydrographs does not show any difference for two DEMs and it is obtained as 3 hours. Maximum flood extents differ for the two DEMs

  18. A photogrammetric DEM of Greenland based on 1978-1987 aerial photos: validation and integration with laser altimetry and satellite-derived DEMs

    NASA Astrophysics Data System (ADS)

    Korsgaard, N. J.; Kjaer, K. H.; Nuth, C.; Khan, S. A.

    2014-12-01

    Here we present a DEM of Greenland covering all ice-free terrain and the margins of the GrIS and local glaciers and ice caps. The DEM is based on the 3534 photos used in the aero-triangulation which were recorded by the Danish Geodata Agency (then the Geodetic Institute) in survey campaigns spanning the period 1978-1987. The GrIS is covered tens of kilometers into the interior due to the large footprints of the photos (30 x 30 km) and control provided by the aero-triangulation. Thus, the data are ideal for providing information for analysis of ice marginal elevation change and also control for satellite-derived DEMs.The results of the validation, error assessments and predicted uncertainties are presented. We test the DEM using Airborne Topographic Mapper (IceBridge ATM) as reference data; evaluate the a posteriori covariance matrix from the aero-triangulation; and co-register DEM blocks of 50 x 50 km to ICESat laser altimetry in order to evaluate the coherency.We complement the aero-photogrammetric DEM with modern laser altimetry and DEMs derived from stereoscopic satellite imagery (AST14DMO) to examine the mass variability of the Northeast Greenland Ice Stream (NEGIS). Our analysis suggests that dynamically-induced mass loss started around 2003 and continued throughout 2014.

  19. Numerical Simulation of High Velocity Impact Phenomenon by the Distinct Element Method (dem)

    NASA Astrophysics Data System (ADS)

    Tsukahara, Y.; Matsuo, A.; Tanaka, K.

    2007-12-01

    Continuous-DEM (Distinct Element Method) for impact analysis is proposed in this paper. Continuous-DEM is based on DEM (Distinct Element Method) and the idea of the continuum theory. Numerical simulations of impacts between SUS 304 projectile and concrete target has been performed using the proposed method. The results agreed quantitatively with the impedance matching method. Experimental elastic-plastic behavior with compression and rarefaction wave under plate impact was also qualitatively reproduced, matching the result by AUTODYN®.

  20. An efficient method for DEM-based overland flow routing

    NASA Astrophysics Data System (ADS)

    Huang, Pin-Chun; Lee, Kwan Tun

    2013-05-01

    The digital elevation model (DEM) is frequently used to represent watershed topographic features based on a raster or a vector data format. It has been widely linked with flow routing equations for watershed runoff simulation. In this study, a recursive formulation was encoded into the conventional kinematic- and diffusion-wave routing algorithms to permit a larger time increment, despite the Courant-Friedrich-Lewy condition having been violated. To meet the requirement of recursive formulation, a novel routing sequence was developed to determine the cell-to-cell computational procedure for the DEM database. The routing sequence can be set either according to the grid elevation in descending order for the kinematic-wave routing or according to the water stage of the grid in descending order for the diffusion-wave routing. The recursive formulation for 1D runoff routing was first applied to a conceptual overland plane to demonstrate the precision of the formulation using an analytical solution for verification. The proposed novel routing sequence with the recursive formulation was then applied to two mountain watersheds for 2D runoff simulations. The results showed that the efficiency of the proposed method was significantly superior to that of the conventional algorithm, especially when applied to a steep watershed.

  1. DEM, tide and velocity over sulzberger ice shelf, West Antarctica

    USGS Publications Warehouse

    Baek, S.; Shum, C.K.; Lee, H.; Yi, Y.; Kwoun, Oh-Ig; Lu, Zhiming; Braun, Andreas

    2005-01-01

    Arctic and Antarctic ice sheets preserve more than 77% of the global fresh water and could raise global sea level by several meters if completely melted. Ocean tides near and under ice shelves shifts the grounding line position significantly and are one of current limitations to study glacier dynamics and mass balance. The Sulzberger ice shelf is an area of ice mass flux change in West Antarctica and has not yet been well studied. In this study, we use repeat-pass synthetic aperture radar (SAR) interferometry data from the ERS-1 and ERS-2 tandem missions for generation of a high-resolution (60-m) Digital Elevation Model (DEM) including tidal deformation detection and ice stream velocity of the Sulzberger Ice Shelf. Other satellite data such as laser altimeter measurements with fine foot-prints (70-m) from NASA's ICESat are used for validation and analyses. The resulting DEM has an accuracy of-0.57??5.88 m and is demonstrated to be useful for grounding line detection and ice mass balance studies. The deformation observed by InSAR is found to be primarily due to ocean tides and atmospheric pressure. The 2-D ice stream velocities computed agree qualitatively with previous methods on part of the Ice Shelf from passive microwave remote-sensing data (i.e., LANDSAT). ?? 2005 IEEE.

  2. GPU based contouring method on grid DEM data

    NASA Astrophysics Data System (ADS)

    Tan, Liheng; Wan, Gang; Li, Feng; Chen, Xiaohui; Du, Wenlong

    2017-08-01

    This paper presents a novel method to generate contour lines from grid DEM data based on the programmable GPU pipeline. The previous contouring approaches often use CPU to construct a finite element mesh from the raw DEM data, and then extract contour segments from the elements. They also need a tracing or sorting strategy to generate the final continuous contours. These approaches can be heavily CPU-costing and time-consuming. Meanwhile the generated contours would be unsmooth if the raw data is sparsely distributed. Unlike the CPU approaches, we employ the GPU's vertex shader to generate a triangular mesh with arbitrary user-defined density, in which the height of each vertex is calculated through a third-order Cardinal spline function. Then in the same frame, segments are extracted from the triangles by the geometry shader, and translated to the CPU-side with an internal order in the GPU's transform feedback stage. Finally we propose a ;Grid Sorting; algorithm to achieve the continuous contour lines by travelling the segments only once. Our method makes use of multiple stages of GPU pipeline for computation, which can generate smooth contour lines, and is significantly faster than the previous CPU approaches. The algorithm can be easily implemented with OpenGL 3.3 API or higher on consumer-level PCs.

  3. Simulation of triaxial response of granular materials by modified DEM

    NASA Astrophysics Data System (ADS)

    Wang, XiaoLiang; Li, JiaChun

    2014-12-01

    A modified discrete element method (DEM) with rolling effect taken into consideration is developed to examine macroscopic behavior of granular materials in this study. Dimensional analysis is firstly performed to establish the relationship between macroscopic mechanical behavior, mesoscale contact parameters at particle level and external loading rate. It is found that only four dimensionless parameters may govern the macroscopic mechanical behavior in bulk. The numerical triaxial apparatus was used to study their influence on the mechanical behavior of granular materials. The parametric study indicates that Poisson's ratio only varies with stiffness ratio, while Young's modulus is proportional to contact modulus and grows with stiffness ratio, both of which agree with the micromechanical model. The peak friction angle is dependent on both inter-particle friction angle and rolling resistance. The dilatancy angle relies on inter-particle friction angle if rolling stiffness coefficient is sufficiently large. Finally, we have recommended a calibration procedure for cohesionless soil, which was at once applied to the simulation of Chende sand using a series of triaxial compression tests. The responses of DEM model are shown in quantitative agreement with experiments. In addition, stress-strain response of triaxial extension was also obtained by numerical triaxial extension tests.

  4. Integration of SAR and DEM data: Geometrical considerations

    NASA Technical Reports Server (NTRS)

    Kropatsch, Walter G.

    1991-01-01

    General principles for integrating data from different sources are derived from the experience of registration of SAR images with digital elevation models (DEM) data. The integration consists of establishing geometrical relations between the data sets that allow us to accumulate information from both data sets for any given object point (e.g., elevation, slope, backscatter of ground cover, etc.). Since the geometries of the two data are completely different they cannot be compared on a pixel by pixel basis. The presented approach detects instances of higher level features in both data sets independently and performs the matching at the high level. Besides the efficiency of this general strategy it further allows the integration of additional knowledge sources: world knowledge and sensor characteristics are also useful sources of information. The SAR features layover and shadow can be detected easily in SAR images. An analytical method to find such regions also in a DEM needs in addition the parameters of the flight path of the SAR sensor and the range projection model. The generation of the SAR layover and shadow maps is summarized and new extensions to this method are proposed.

  5. DEM modeling of flexible structures against granular material avalanches

    NASA Astrophysics Data System (ADS)

    Lambert, Stéphane; Albaba, Adel; Nicot, François; Chareyre, Bruno

    2016-04-01

    This article presents the numerical modeling of flexible structures intended to contain avalanches of granular and coarse material (e.g. rock slide, a debris slide). The numerical model is based on a discrete element method (YADE-Dem). The DEM modeling of both the flowing granular material and the flexible structure are detailed before presenting some results. The flowing material consists of a dry polydisperse granular material accounting for the non-sphericity of real materials. The flexible structure consists in a metallic net hanged on main cables, connected to the ground via anchors, on both sides of the channel, including dissipators. All these components were modeled as flexible beams or wires, with mechanical parameters defined from literature data. The simulation results are presented with the aim of investigating the variability of the structure response depending on different parameters related to the structure (inclination of the fence, with/without brakes, mesh size opening), but also to the channel (inclination). Results are then compared with existing recommendations in similar fields.

  6. a Near-Global Bare-Earth dem from Srtm

    NASA Astrophysics Data System (ADS)

    Gallant, J. C.; Read, A. M.

    2016-06-01

    The near-global elevation product from NASA's Shuttle Radar Topographic Mission (SRTM) has been widely used since its release in 2005 at 3 arcsecond resolution and the release of the 1 arcsecond version in late 2014 means that the full potential of the SRTM DEM can now be realised. However the routine use of SRTM for analytical purposes such as catchment hydrology, flood inundation, habitat mapping and soil mapping is still seriously impeded by the presence of artefacts in the data, primarily the offsets due to tree cover and the random noise. This paper describes the algorithms being developed to remove those offsets, based on the methods developed to produce the Australian national elevation model from SRTM data. The offsets due to trees are estimated using the GlobeLand30 (National Geomatics Center of China) and Global Forest Change (University of Maryland) products derived from Landsat, along with the ALOS PALSAR radar image data (JAXA) and the global forest canopy height map (NASA). The offsets are estimated using several processes and combined to produce a single continuous tree offset layer that is subtracted from the SRTM data. The DEM products will be made freely available on completion of the first draft product, and the assessment of that product is expected to drive further improvements to the methods.

  7. Generating, Comparing and Exploiting DEMs for Hydrological Applications over the Galapagos Islands

    NASA Astrophysics Data System (ADS)

    D'Ozouville, N.; Benveniste, J.; Deffontaines, B.; Violette, S.; de Marsily, G.; Wegmuller, U.

    Understanding the hydrological cycle of the Galapagos Islands will contribute to more efficient water management in insular basaltic environments with growing anthropogenic pressure and ecosystems to preserve. Lack of essential existing in-situ data such as topography led to retrieving this information from other sources. We present the generation from satellite data of digital elevation model (DEM) and its exploitation for the Santa Cruz island. An interferometric DEM was generated from ASAR (ENVISAT) data with Atlantis EarthView and a radargrammetric DEM using multiple incidence angle capacity of ASAR was generated by Gamma Remote Sensing. SRTM 90 m resolution data (NASA) and a digitalised topographic contour DEM (M. Souris, IRD) were used to aid the phase unwrapping and for comparison and validation. Combining the radargrammetric DEM (overall accurate, few detail) and the interferometric DEM (unresolved in uncoherent areas but high definition in coherent areas), it is hoped to achieve a resolution better than the 90 m SRTM data and which can be compared to the 30 m resolution SRTM data which has been requested from NASA. Drainage networks were extracted and identified on Santa Cruz and zones of interest for the setting up of hydrological instruments are defined. Radargrammetric versus interferometric method of DEM generation in volcanic insular environment is reviewed in this work. Resolution of the DEM will be a limiting factor to the accuracy of transposition from image to fieldwork. Background hydrological information from the DEM can be used in the hydrological modelling.

  8. A seamless, high-resolution digital elevation model (DEM) of the north-central California coast

    USGS Publications Warehouse

    Foxgrover, Amy C.; Barnard, Patrick L.

    2012-01-01

    A seamless, 2-meter resolution digital elevation model (DEM) of the north-central California coast has been created from the most recent high-resolution bathymetric and topographic datasets available. The DEM extends approximately 150 kilometers along the California coastline, from Half Moon Bay north to Bodega Head. Coverage extends inland to an elevation of +20 meters and offshore to at least the 3 nautical mile limit of state waters. This report describes the procedures of DEM construction, details the input data sources, and provides the DEM for download in both ESRI Arc ASCII and GeoTIFF file formats with accompanying metadata.

  9. A New DEM Generalization Method Based on Watershed and Tree Structure

    PubMed Central

    Chen, Yonggang; Ma, Tianwu; Chen, Xiaoyin; Chen, Zhende; Yang, Chunju; Lin, Chenzhi; Shan, Ligang

    2016-01-01

    The DEM generalization is the basis of multi-dimensional observation, the basis of expressing and analyzing the terrain. DEM is also the core of building the Multi-Scale Geographic Database. Thus, many researchers have studied both the theory and the method of DEM generalization. This paper proposed a new method of generalizing terrain, which extracts feature points based on the tree model construction which considering the nested relationship of watershed characteristics. The paper used the 5 m resolution DEM of the Jiuyuan gully watersheds in the Loess Plateau as the original data and extracted the feature points in every single watershed to reconstruct the DEM. The paper has achieved generalization from 1:10000 DEM to 1:50000 DEM by computing the best threshold. The best threshold is 0.06. In the last part of the paper, the height accuracy of the generalized DEM is analyzed by comparing it with some other classic methods, such as aggregation, resample, and VIP based on the original 1:50000 DEM. The outcome shows that the method performed well. The method can choose the best threshold according to the target generalization scale to decide the density of the feature points in the watershed. Meanwhile, this method can reserve the skeleton of the terrain, which can meet the needs of different levels of generalization. Additionally, through overlapped contour contrast, elevation statistical parameters and slope and aspect analysis, we found out that the W8D algorithm performed well and effectively in terrain representation. PMID:27517296

  10. MIT LMFBR blanket research project. Final summary report

    SciTech Connect

    Driscoll, M.J.

    1983-08-01

    This is a final summary report on an experimental and analytical program for the investigation of LMFBR blanket characteristics carried out at MIT in the period 1969 to 1983. During this span of time, work was carried out on a wide range of subtasks, ranging from neutronic and photonic measurements in mockups of blankets using the Blanket Test Facility at the MIT Research Reactor, to analytic/numerical investigations of blanket design and economics. The main function of this report is to serve as a resource document which will permit ready reference to the more detailed topical reports and theses issued over the years on the various aspects of project activities. In addition, one aspect of work completed during the final year of the project, on doubly-heterogeneous blanket configurations, is documented for the record.

  11. MIT-Skywalker: Evaluating comfort of bicycle/saddle seat.

    PubMed

    Goncalves, Rogerio S; Hamilton, Taya; Daher, Ali R; Hirai, Hiroaki; Krebs, Hermano I

    2017-07-01

    The MIT-Skywalker is a robotic device developed for the rehabilitation of gait and balance after a neurological injury. This device has been designed based on the concept of a passive walker and provides three distinct training modes: discrete movement, rhythmic movement, and balance training. In this paper, we present our efforts to evaluate the comfort of a bicycle/saddle seat design for the system's novel actuated body weight support device. We employed different bicycle and saddle seats and evaluated comfort using objective and subjective measures. Here we will summarize the results obtained from a study of fifteen healthy subjects and one stroke patient that led to the selection of a saddle seat design for the MIT-Skywalker.

  12. The Harvard-MIT PHD Program in Bioastronautics

    NASA Astrophysics Data System (ADS)

    Young, Laurence R.; Natapoff, Alan

    2008-06-01

    The National Space Biomedical Research Institute (NSBRI)1 supports a PhD program in Space Life Sciences with a specialty in Bioastronautics at MIT. (A sibling program operates at TAMU.) It gives broad training in life sciences, emphasizes hands-on field experience, provides access to laboratories in the Harvard-MIT community for thesis research, and prepares students for many options in space biomedicine. The Program trains prospective leaders in the field able to manage the challenges of design for the life-hostile space environment. Beyond subject and thesis work, students participate in a summer internship and a clinical preceptorship at a NASA center--and an introduction to clinical medicine and medical engineering.

  13. Utopie: Eine Geschichte aus dem 15. Jahrhundert fur die Siebte Klasse, mit Ubungen (Utopia: A View of the 15th Century for the Seventh Class, with Exercises).

    ERIC Educational Resources Information Center

    Stott, Michael

    This German language textbook is intended for classroom use. The theme of the text relates to the Renaissance, and the narrative is based on Sir Thomas More's "Utopia" (1516) and relates to the experiences of its central character Raphael among the inhabitants of the strange island. Each chapter touches lightly on some thought provoking…

  14. Entdeckung elektroschwacher Produktion einzelner Top-Quarks mit dem CDF II Experiment; Discovery electroweak production of single top quarks with the CDF II Experiment

    SciTech Connect

    Luck, Jan

    2009-01-01

    This thesis presents a neural network search for combined as well as separate s- and t-channel single top-quark production with the CDF II experiment at the Tevatron using 3.2 fb-1 of collision data. It is the twelfth thesis dealing with single top-quark production performed within the CDF Collaboration, whereas three have been done in Run I [53–55] and eight in Run II [23, 25, 28, 39, 56–59].

  15. Ausbildung in der Arbeit mit dem Sprachlabor fuer Lehramtskandidaten der Anglistik. Ein Erfahrungsbericht (Training in Language Laboratory Work for English Teacher Candidates. A Report on an Experience)

    ERIC Educational Resources Information Center

    Gorbahn, Adeline; Wilpert, Klaus

    1975-01-01

    Reports on work at the University of Erlangen beginners' seminar on language laboratory work. This led to production of original laboratory exercises, which were tried out in a Gymnasium class. The aim was to introduce teacher candidates early to problems attending the introduction of language laboratories. (Text is in German.) (IFS/WGA)

  16. Shuttle radar DEM hydrological correction for erosion modelling in small catchments

    NASA Astrophysics Data System (ADS)

    Jarihani, Ben; Sidle, Roy; Bartley, Rebecca

    2016-04-01

    Digital Elevation Models (DEMs) that accurately replicate both landscape form and processes are critical to support modelling of environmental processes. Catchment and hillslope scale runoff and sediment processes (i.e., patterns of overland flow, infiltration, subsurface stormflow and erosion) are all topographically mediated. In remote and data-scarce regions, high resolution DEMs (LiDAR) are often not available, and moderate to course resolution digital elevation models (e.g., SRTM) have difficulty replicating detailed hydrological patterns, especially in relatively flat landscapes. Several surface reconditioning algorithms (e.g., Smoothing) and "Stream burning" techniques (e.g., Agree or ANUDEM), in conjunction with representation of the known stream networks, have been used to improve DEM performance in replicating known hydrology. Detailed stream network data are not available at regional and national scales, but can be derived at local scales from remotely-sensed data. This research explores the implication of high resolution stream network data derived from Google Earth images for DEM hydrological correction, instead of using course resolution stream networks derived from topographic maps. The accuracy of implemented method in producing hydrological-efficient DEMs were assessed by comparing the hydrological parameters derived from modified DEMs and limited high-resolution airborne LiDAR DEMs. The degree of modification is dominated by the method used and availability of the stream network data. Although stream burning techniques improve DEMs hydrologically, these techniques alter DEM characteristics that may affect catchment boundaries, stream position and length, as well as secondary terrain derivatives (e.g., slope, aspect). Modification of a DEM to better reflect known hydrology can be useful, however, knowledge of the magnitude and spatial pattern of the changes are required before using a DEM for subsequent analyses.

  17. Extraction of Hydrological Proximity Measures from DEMs using Parallel Processing

    SciTech Connect

    Tesfa, Teklu K.; Tarboton, David G.; Watson, Daniel W.; Schreuders, Kimberly A.; Baker, Matthew M.; Wallace, Robert M.

    2011-12-01

    Land surface topography is one of the most important terrain properties which impact hydrological, geomorphological, and ecological processes active on a landscape. In our previous efforts to develop a soil depth model based upon topographic and land cover variables, we extracted a set of hydrological proximity measures (HPMs) from a Digital Elevation Model (DEM) as potential explanatory variables for soil depth. These HPMs may also have other, more general modeling applicability in hydrology, geomorphology and ecology, and so are described here from a general perspective. The HPMs we derived are variations of the distance up to ridge points (cells with no incoming flow) and variations of the distance down to stream points (cells with a contributing area greater than a threshold), following the flow path. These HPMs were computed using the D-infinity flow model that apportions flow between adjacent neighbors based on the direction of steepest downward slope on the eight triangular facets constructed in a 3 x 3 grid cell window using the center cell and each pair of adjacent neighboring grid cells in turn. The D-infinity model typically results in multiple flow paths between 2 points on the topography, with the result that distances may be computed as the minimum, maximum or average of the individual flow paths. In addition, each of the HPMs, are calculated vertically, horizontally, and along the land surface. Previously, these HPMs were calculated using recursive serial algorithms which suffered from stack overflow problems when used to process large datasets, limiting the size of DEMs that could be analyzed using that method to approximately 7000 x 7000 cells. To overcome this limitation, we developed a message passing interface (MPI) parallel approach for calculating these HPMs. The parallel algorithms of the HPMs spatially partition the input grid into stripes which are each assigned to separate processes for computation. Each of those processes then uses a

  18. MIT Laboratory for Computer Science Progress Report 27

    DTIC Science & Technology

    1990-06-01

    plications to computer graphics and database retrieval systems. The survey paper identifies three general methods for range queries in computational geometry ...Massachusetts Laboratory for Institute of Computer Science Technology Progress Report July 1989- 27 a) June 1990 00 N Nv NOV C510D The work reported ...Arlington, VA 22217 11. TITLE (Include Security Clasvfication) MIT Laboratory for Computer Science Progress Report - 27 12. PERSONAL AUTHOR(S) M.L

  19. Phylogenetic relationships of the Gomphales based on nuc-25S-rDNA, mit-12S-rDNA, and mit-atp6-DNA combined sequences

    Treesearch

    Admir J. Giachini; Kentaro Hosaka; Eduardo Nouhra; Joseph Spatafora; James M. Trappe

    2010-01-01

    Phylogenetic relationships among Geastrales, Gomphales, Hysterangiales, and Phallales were estimated via combined sequences: nuclear large subunit ribosomal DNA (nuc-25S-rDNA), mitochondrial small subunit ribosomal DNA (mit-12S-rDNA), and mitochondrial atp6 DNA (mit-atp6-DNA). Eighty-one taxa comprising 19 genera and 58 species...

  20. DEM Simulation of Particle Stratification and Segregation in Stockpile Formation

    NASA Astrophysics Data System (ADS)

    Zhang, Dizhe; Zhou, Zongyan; Pinson, David

    2017-06-01

    Granular stockpiles are commonly observed in nature and industry, and their formation has been extensively investigated experimentally and mathematically in the literature. One of the striking features affecting properties of stockpiles are the internal patterns formed by the stratification and segregation processes. In this work, we conduct a numerical study based on DEM (discrete element method) model to study the influencing factors and triggering mechanisms of these two phenomena. With the use of a previously developed mixing index, the effects of parameters including size ratio, injection height and mass ratio are investigated. We found that it is a void-filling mechanism that differentiates the motions of particles with different sizes. This mechanism drives the large particles to flow over the pile surface and segregate at the pile bottom, while it also pushes small particles to fill the voids between large particles, giving rise to separate layers. Consequently, this difference in motion will result in the observed stratification and segregation phenomena.

  1. SPI Analysis of the Supernova Remnant DEM L71

    NASA Astrophysics Data System (ADS)

    Frank, Kari A.; Dwarkadas, Vikram; Burrows, David N.; Aisyah Mansoor, Siti; Crum, Ryan M.

    2017-08-01

    Supernova remnants are complex, three-dimensional objects; properly accounting for this complexity when modeling the resulting X-ray emission presents quite a challenge and makes it difficult to accurately characterize the properties of the full SNR volume. The SPIES (Smoothed Particle Inference Exploration of Supernova Remnants) project aims to address this challenge by applying a fundamentally different approach to analyzing X-ray observations of SNRs. Smoothed Particle Inference (SPI) is a Bayesian modeling process that fits a population of gas blobs ("smoothed particles") such that their superposed emission reproduces the observed spatial and spectral distribution of photons. We present here the results of an SPI analysis of the Type Ia supernova remnant DEM L71. Among other results, we find that despite its regular appearance, the temperature and other parameter maps exhibit irregular substructure.

  2. DEM simulation of the granular Maxwell's Demon under zero gravity

    NASA Astrophysics Data System (ADS)

    Wang, Wenguang; Zhou, Zhigang; Zong, Jin; Hou, Meiying

    2017-06-01

    In this work, granular segregation in a two-compartment cell (Maxwell's Demon) under zero gravity is studied numerically by DEM simulation for comparison with the experimental observation in satellite SJ-10. The effect of three parameters: the total number of particlesN, the excitation strengthΓ, and the position of the window coupling the two compartments, on the segregationɛ and the waiting timeτ are investigated. In the simulation, non-zero segregation under zero gravity is obtained, and the segregation ɛ is found independent of the excitation strengthΓ. The waiting time τ, however, depends strongly onΓ. For higher acceleration Γ, |ɛi| reaches steady state valueɛ faster.

  3. Influence of dem in Watershed Management as Flood Zonation Mapping

    NASA Astrophysics Data System (ADS)

    Alrajhi, Muhamad; Khan, Mudasir; Afroz Khan, Mohammad; Alobeid, Abdalla

    2016-06-01

    Despite of valuable efforts from working groups and research organizations towards flood hazard reduction through its program, still minimal diminution from these hazards has been realized. This is mainly due to the fact that with rapid increase in population and urbanization coupled with climate change, flood hazards are becoming increasingly catastrophic. Therefore there is a need to understand and access flood hazards and develop means to deal with it through proper preparations, and preventive measures. To achieve this aim, Geographical Information System (GIS), geospatial and hydrological models were used as tools to tackle with influence of flash floods in the Kingdom of Saudi Arabia due to existence of large valleys (Wadis) which is a matter of great concern. In this research paper, Digital Elevation Models (DEMs) of different resolution (30m, 20m,10m and 5m) have been used, which have proven to be valuable tool for the topographic parameterization of hydrological models which are the basis for any flood modelling process. The DEM was used as input for performing spatial analysis and obtaining derivative products and delineate watershed characteristics of the study area using ArcGIS desktop and its Arc Hydro extension tools to check comparability of different elevation models for flood Zonation mapping. The derived drainage patterns have been overlaid over aerial imagery of study area, to check influence of greater amount of precipitation which can turn into massive destructions. The flow accumulation maps derived provide zones of highest accumulation and possible flow directions. This approach provide simplified means of predicting extent of inundation during flood events for emergency action especially for large areas because of large coverage area of the remotely sensed data.

  4. Two Preliminary SRTM DEMs Within the Amazon Basin

    NASA Astrophysics Data System (ADS)

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

    2002-12-01

    Digital topography provides important measures, such as hillslope lengths and flow path networks, for understanding hydrologic and geomorphic processes (e.g., runoff response to land use change and floodplain inundation volume). Two preliminary Shuttle Radar Topography Mission digital elevation models of Manaus (1S to 5S and 59W to 63W) and Rondonia (9S to 12S and 61W to 64W) were received from NASA JPL in August 2002. The "PI Processor" produced these initial DEM segments and we are using them to assess the initial accuracy of the interferometrically derived heights and for hydrologic research. The preliminary SRTM derived absolute elevations across the Amazon floodplain in the Cabaliana region generally range from 5 to 15 m with reported errors of 1 to 3 m. This region also includes some preliminary elevations that are erroneously negative. However, topographic contours on 1:100,000 scale quadrangles of 1978 to 1980 vintage indicate elevations of 20 to 30 m. Because double-bounce travel paths are possible over the sparsely vegetated and very-flat 2400 sq-km water surface of the Balbina reservoir near Manaus, it serves to identify the relative accuracy of the SRTM heights. Here, cell-to-cell height changes are generally 0 to 1 m and changes across a ~100 km transect rarely exceed 3 m. Reported errors throughout the transect range from 1 to 2 m with some errors up to 5 m. Deforestation in Rondonia is remarkably clear in the C-band DEM where elevations are recorded from the canopy rather than bare earth. Here, elevation changes are ~30 m (with reported 1 to 2 m errors) across clear-cut areas. Field derived canopy heights are in agreement with this change. Presently, we are deriving stream networks in the Amazon floodplain for comparison with our previous network extraction from JERS-1 SAR mosaics and for hydrologic modeling.

  5. Evaluating Error of LIDAR Derived dem Interpolation for Vegetation Area

    NASA Astrophysics Data System (ADS)

    Ismail, Z.; Khanan, M. F. Abdul; Omar, F. Z.; Rahman, M. Z. Abdul; Mohd Salleh, M. R.

    2016-09-01

    Light Detection and Ranging or LiDAR data is a data source for deriving digital terrain model while Digital Elevation Model or DEM is usable within Geographical Information System or GIS. The aim of this study is to evaluate the accuracy of LiDAR derived DEM generated based on different interpolation methods and slope classes. Initially, the study area is divided into three slope classes: (a) slope class one (0° - 5°), (b) slope class two (6° - 10°) and (c) slope class three (11° - 15°). Secondly, each slope class is tested using three distinctive interpolation methods: (a) Kriging, (b) Inverse Distance Weighting (IDW) and (c) Spline. Next, accuracy assessment is done based on field survey tachymetry data. The finding reveals that the overall Root Mean Square Error or RMSE for Kriging provided the lowest value of 0.727 m for both 0.5 m and 1 m spatial resolutions of oil palm area, followed by Spline with values of 0.734 m for 0.5 m spatial resolution and 0.747 m for spatial resolution of 1 m. Concurrently, IDW provided the highest RMSE value of 0.784 m for both spatial resolutions of 0.5 and 1 m. For rubber area, Spline provided the lowest RMSE value of 0.746 m for 0.5 m spatial resolution and 0.760 m for 1 m spatial resolution. The highest value of RMSE for rubber area is IDW with the value of 1.061 m for both spatial resolutions. Finally, Kriging gave the RMSE value of 0.790m for both spatial resolutions.

  6. Digital elevation model (DEM) of Cascadia, latitude 39N-53N, longitude 116W-133W

    USGS Publications Warehouse

    Haugerud, Ralph A.

    1999-01-01

    This report contains a 250-meter digital elevation model (DEM) for Cascadia (latitude 39N - 53N, longitude 116W - 133W), a region that encompasses the Cascade volcanic arc, the Cascadia subduction zone, and the Juan de Fuca Ridge system. The DEM is distributed as file cascdem.tar.gz (39 MB; 78MB uncompressed).

  7. Topographic representation using DEMs and its applications to active tectonics research

    NASA Astrophysics Data System (ADS)

    Oguchi, T.; Lin, Z.; Hayakawa, Y. S.

    2016-12-01

    Identifying topographic deformations due to active tectonics has been a principal issue in tectonic geomorphology. It provides useful information such as whether a fault has been active during the recent past. Traditionally, field observations, conventional surveying, and visual interpretation of topographic maps, aerial photos, and satellite images were the main methods for such geomorphological investigations. However, recent studies have been utilizing digital elevation models (DEMs) to visualize and quantitatively analyze landforms. There are many advantages to the use of DEMs for research in active tectonics. For example, unlike aerial photos and satellite images, DEMs show ground conditions without vegetation and man-made objects such as buildings, permitting direct representation of tectonically deformed landforms. Recent developments and advances in airborne LiDAR also allow the fast creation of DEMs even in vegetated areas such as forested lands. In addition, DEMs enable flexible topographic visualization based on various digital cartographic and computer-graphic techniques, facilitating identification of particular landforms such as active faults. Further, recent progress in morphometric analyses using DEMs can be employed to quantitatively represent topographic characteristics, and objectively evaluate tectonic deformation and the properties of related landforms. This paper presents a review of DEM applications in tectonic geomorphology, with attention to historical development, recent advances, and future perspectives. Examples are taken mainly from Japan, a typical tectonically active country. The broader contributions of DEM-based active tectonics research to other fields, such as fluvial geomorphology and geochronology, will also be discussed.

  8. TanDEM-X Mission: Overview and Evaluation of intermediate Results

    NASA Astrophysics Data System (ADS)

    Soergel, U.; Jacobsen, K.; Schack, L.

    2013-10-01

    The German Aerospace Center (DLR, Deutsches Zentrum für Luft- und Raumfahrt) currently conducts the bistatic interferometric synthetic aperture radar (SAR) Mission TanDEM-X, which shall result in a DEM of global coverage in an unprecedented resolution and accuracy according to DTED level 3 standard. The mission is based on the two SAR satellites TerraSAR-X and TanDEM-X that have been launched in June 2007 and 2010, respectively. After the commissioning phase of TanDEM satellite and the orbital adjustment the bistatic image acquisition in close formation began end of 2010. The data collection for the mission is scheduled to last about three years, i.e., the bigger part of the required data have been already gathered. Based on this data DLR will conduct several processing steps in order to come up finally with a global and seamless DEM of the Earth's landmass which shall meet the envisaged specifications. Since the entire mission is an endeavor in the framework of a private-public-partnership, the private partner, Astrium, will eventually commercialize the DEM product. In this paper, we will provide an overview of the data collection and the deliverables that will come along with TanDEM-X mission. Furthermore, we will analyze a DEM derived from early stage immediate products of the mission.

  9. Assoziativspeicher und eine erste Skizze von Konrad Zuse aus dem Jahre 1943

    NASA Astrophysics Data System (ADS)

    Waldschmidt, Klaus

    In dem Beitrag wird eine Handskizze von Konrad Zuse aus dem Jahre 1943 eines assoziativen Speichers in Relaistechnik diskutiert. Die Diskussion ist eingebettet in die Grundlagen des assoziativen Speicherproblems. Zum Schluss des Beitrages werden einige Vorschläge zu MOSRealisierung der Zuse-Schaltung unterbreitet.

  10. Icesat Validation of Tandem-X I-Dems Over the UK

    NASA Astrophysics Data System (ADS)

    Feng, L.; Muller, J.-P.

    2016-06-01

    From the latest TanDEM-X mission (bistatic X-Band interferometric SAR), globally consistent Digital Elevation Model (DEM) will be available from 2017, but their accuracy has not yet been fully characterised. This paper presents the methods and implementation of statistical procedures for the validation of the vertical accuracy of TanDEM-X iDEMs at grid-spacing of approximately 12.5 m, 30 m and 90 m based on processed ICESat data over the UK in order to assess their potential extrapolation across the globe. The accuracy of the TanDEM-X iDEM in UK was obtained as follows: against ICESat GLA14 elevation data, TanDEM-X iDEM has -0.028±3.654 m over England and Wales and 0.316 ± 5.286 m over Scotland for 12 m, -0.073 ± 6.575 m for 30 m, and 0.0225 ± 9.251 m at 90 m. Moreover, 90 % of all results at the three resolutions of TanDEM-X iDEM data (with a linear error at 90 % confidence level) are below 16.2 m. These validation results also indicate that derivative topographic parameters (slope, aspect and relief) have a strong effect on the vertical accuracy of the TanDEM-X iDEMs. In high-relief and large slope terrain, large errors and data voids are frequent, and their location is strongly influenced by topography, whilst in the low- to medium-relief and low slope sites, errors are smaller. ICESat derived elevations are heavily influenced by surface slope within the 70 m footprint as well as there being slope dependent errors in the TanDEM-X iDEMs.

  11. Global Maps from Interferometeric TanDEM-X Data: Applications and Potentials

    NASA Astrophysics Data System (ADS)

    Rizzoli, Paola; Martone, Michele; Brautigam, Benjamin; Zink, Manfred

    2015-05-01

    TanDEM-X is a spaceborne Synthetic Aperture Radar (SAR) mission, whose goal is the generation of a global Digital Elevation Model (DEM) with unprecedented accuracy, by using interferometric SAR (InSAR) techniques (InSAR). TanDEM-X offers a huge global data set of bistatic InSAR acquisitions, each of them supplemented by quick look images of different SAR quantities, such as amplitude, coherence, and DEM. Global quick look mosaics of the interferometric coherence and of the relative height error can be considered for mission performance monitoring and acquisition strategy optimization. The aim of this paper is to present the use of such mosaics within the TanDEM-X mission and to show their potentials for future scientific applications for example in the fields of glaciology and forestry.

  12. A Comparative Study of Radar Stereo and Interferometry for DEM Generation

    NASA Astrophysics Data System (ADS)

    Gelautz, M.; Paillou, P.; Chen, C. W.; Zebker, H. A.

    2004-06-01

    In this experiment, we derive and compare radar stereo and interferometric elevation models (DEMs) of a study site in Djibouti, East Africa. As test data, we use a Radarsat stereo pair and ERS-2 and Radarsat interferometric data. Comparison of the reconstructed DEMs with a SPOT reference DEM shows that in regions of high coherence the DEMs produced by interferometry are of much better quality than the stereo result. However, the interferometric error histograms also show some pronounced outliers due to decorrelation and phase unwrapping problems on forested mountain slopes. The more robust stereo result is able to capture the general terrain shape, but finer surface details are lost. A fusion experiment demonstrates that merging the stereoscopic and interferometric DEMs by utilizing coherence- derived weights can significantly improve the accuracy of the computed elevation maps.

  13. Open-Source Digital Elevation Model (DEMs) Evaluation with GPS and LiDAR Data

    NASA Astrophysics Data System (ADS)

    Khalid, N. F.; Din, A. H. M.; Omar, K. M.; Khanan, M. F. A.; Omar, A. H.; Hamid, A. I. A.; Pa'suya, M. F.

    2016-09-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer-Global Digital Elevation Model (ASTER GDEM), Shuttle Radar Topography Mission (SRTM), and Global Multi-resolution Terrain Elevation Data 2010 (GMTED2010) are freely available Digital Elevation Model (DEM) datasets for environmental modeling and studies. The quality of spatial resolution and vertical accuracy of the DEM data source has a great influence particularly on the accuracy specifically for inundation mapping. Most of the coastal inundation risk studies used the publicly available DEM to estimated the coastal inundation and associated damaged especially to human population based on the increment of sea level. In this study, the comparison between ground truth data from Global Positioning System (GPS) observation and DEM is done to evaluate the accuracy of each DEM. The vertical accuracy of SRTM shows better result against ASTER and GMTED10 with an RMSE of 6.054 m. On top of the accuracy, the correlation of DEM is identified with the high determination of coefficient of 0.912 for SRTM. For coastal zone area, DEMs based on airborne light detection and ranging (LiDAR) dataset was used as ground truth data relating to terrain height. In this case, the LiDAR DEM is compared against the new SRTM DEM after applying the scale factor. From the findings, the accuracy of the new DEM model from SRTM can be improved by applying scale factor. The result clearly shows that the value of RMSE exhibit slightly different when it reached 0.503 m. Hence, this new model is the most suitable and meets the accuracy requirement for coastal inundation risk assessment using open source data. The suitability of these datasets for further analysis on coastal management studies is vital to assess the potentially vulnerable areas caused by coastal inundation.

  14. The development of form two mathematics i-Think module (Mi-T2)

    NASA Astrophysics Data System (ADS)

    Yao, Foo Jing; Abdullah, Mohd Faizal Nizam Lee; Tien, Lee Tien

    2017-05-01

    This study aims to develop a training module i-THINK Mathematics Form Two (Mi-T2) to increase the higher-order thinking skills of students. The Mi-T2 training module was built based on the Sidek Module Development Model (2001). Constructivist learning theory, cognitive learning theory, i-THINK map and higher order thinking skills were the building blocks of the module development. In this study, researcher determined the validity and reliability of Mi-T2 module. The design being used in this study was descriptive study. To determine the needs of Mi-T2 module, questionnaires and literature review were used to collect data. When the need of the module was determined, the module was built and a pilot study was conducted to test the reliability of the Mi-T2 module. The pilot study was conducted at a secondary school in North Kinta, Perak. A Form Two class was selected to be the sample study through clustered random sampling. The pilot study was conducted for two months and one topic had been studied. The Mi-T2 module was evaluated by five expert panels to determine the content validity of the module. The instruments being used in the study were questionnaires about the necessity of the Mi-T2 module for guidance, questionnaires about the validity of the module and questionnaires concerning the reliability of the module. Statistical analysis was conducted to determine the validity and reliability coefficients of the Mi-T2 module. The content validity of Mi-T2 module was determined by Cohen's Kappa's (1968) agreement coefficient and the reliability of Mi-T2 module was determined by Cronbach Alpha's value scale. The content validity of Mi-T2 module was 0.89 and the Cronbach Alpha's value of Mi-T2 module was 0.911.

  15. Effect of DEM Source and Resolution on Extracting River Network and Watershed within Multi-Lake Area in Tibet

    NASA Astrophysics Data System (ADS)

    Li, Yang; Li, Gang; Lin, Hui

    2014-11-01

    DEM defines drainage structures and basin through conducting overland flow simulation. Two matured DEM Sources are SRTM DEM (Shuttle Radar Topographic Mission) and ASTER GDEM (Advanced Space borne Thermal Emission and Reflection Radiometer Global Digital Elevation Model); The accuracy of hydrological characters that derived from DEM decreased from high resolution to coarse resolution and appeared to be different in different data source (Vaze,Teng, & Spencer, 2010).

  16. Impacts of DEM uncertainties on critical source areas identification for non-point source pollution control based on SWAT model

    NASA Astrophysics Data System (ADS)

    Xu, Fei; Dong, Guangxia; Wang, Qingrui; Liu, Lumeng; Yu, Wenwen; Men, Cong; Liu, Ruimin

    2016-09-01

    The impacts of different digital elevation model (DEM) resolutions, sources and resampling techniques on nutrient simulations using the Soil and Water Assessment Tool (SWAT) model have not been well studied. The objective of this study was to evaluate the sensitivities of DEM resolutions (from 30 m to 1000 m), sources (ASTER GDEM2, SRTM and Topo-DEM) and resampling techniques (nearest neighbor, bilinear interpolation, cubic convolution and majority) to identification of non-point source (NPS) critical source area (CSA) based on nutrient loads using the SWAT model. The Xiangxi River, one of the main tributaries of Three Gorges Reservoir in China, was selected as the study area. The following findings were obtained: (1) Elevation and slope extracted from the DEMs were more sensitive to DEM resolution changes. Compared with the results of the 30 m DEM, 1000 m DEM underestimated the elevation and slope by 104 m and 41.57°, respectively; (2) The numbers of subwatersheds and hydrologic response units (HRUs) were considerably influenced by DEM resolutions, but the total nitrogen (TN) and total phosphorus (TP) loads of each subwatershed showed higher correlations with different DEM sources; (3) DEM resolutions and sources had larger effects on CSAs identifications, while TN and TP CSAs showed different response to DEM uncertainties. TN CSAs were more sensitive to resolution changes, exhibiting six distribution patterns at all DEM resolutions. TP CSAs were sensitive to source and resampling technique changes, exhibiting three distribution patterns for DEM sources and two distribution patterns for DEM resampling techniques. DEM resolutions and sources are the two most sensitive SWAT model DEM parameters that must be considered when nutrient CSAs are identified.

  17. Wirksamkeit und Sicherheit von Fumarsäureestern in Kombination mit Phototherapie bei Patienten mit moderater bis schwerer Plaque-Psoriasis (FAST).

    PubMed

    Weisenseel, Peter; Reich, Kristian; Griemberg, Wiebke; Merten, Katharina; Gröschel, Christine; Gomez, Natalie Nunez; Taipale, Kirsi; Bräu, Beate; Zschocke, Ina

    2017-02-01

    Die Behandlung von Psoriasis-Patienten mit einer Kombination aus Fumarsäureestern (FSE, Fumaderm(®) ) und Phototherapie (UV) ist verbreitet, wurde aber im Rahmen von Studien wenig untersucht. Bisher liegen lediglich Daten aus einer kleinen Pilotstudie vor. Intention dieser Studie war, eine FSE/UV-Kombinationsbehandlung an einem größeren Patientenkollektiv mit mittelschwerer bis schwerer Psoriasis zu untersuchen. In dieser prospektiven, multizentrischen, nichtinterventionellen Studie wurden Daten von Patienten mit FSE/UV-Kombinationstherapie hinsichtlich der Wirksamkeit (PGA' PASI, DLQI, EQ-5D), Sicherheit und Dosierung über einen Zeitraum von zwölf Monaten erfasst und mit Daten einer retrospektiven Studie mit FSE-Monotherapie verglichen. Es wurden Daten von 363 Patienten ausgewertet. Unter der Kombinationstherapie verbesserten sich alle Wirksamkeitsparameter deutlich. Im Vergleich zur Monotherapie mit FSE konnte durch die Kombination mit UV ein schnellerer Wirkeintritt erzielt werden, wobei nach zwölf Monaten kein Unterschied in der Wirksamkeit bestand. Die Dauer und Art der Phototherapie zeigte keinen Einfluss auf die Wirksamkeitsparameter. Allgemein wurde die Kombinationstherapie gut vertragen. Unerwünschte Ereignisse wurden bei 7 % der Patienten berichtet. Die FSE/UV Kombinationstherapie zeigt eine gute Wirksamkeit und Verträglichkeit und kann zu einem schnelleren Wirkeintritt führen. Eine Kombinationstherapie erscheint vor allem in den ersten drei Monaten der FSE Behandlung sinnvoll. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  18. Stress analysis during slope failure from DEM simulations

    NASA Astrophysics Data System (ADS)

    Katz, O.; Morgan, J. K.

    2012-04-01

    We used Discrete Element Method (DEM) simulations to study the initiation and evolution of landsliding, with a focus on the development and propagation of the sliding plane, and on the effects of material strength on the behavior of the slope material during landsliding. Our simulated slopes were constructed of homogeneous materials, settled under gravity, bonded, and excavated to produce 70 deg slopes of 1050 m in height. Nine simulations were carried out, each using a different value of cohesions, ranging from 0.7 to 4.2 MPa (quantified through DEM direct shear simulations on representative materials). In each of our simulations, failure initiated at the foot of the slope, accompanied by disintegration of the slope material. Failure then propagated upward to the slope crest with further material disintegration. A discrete detachment surface formed below the disintegrated material. Downslope movement of the failed material (i.e. landsliding) occurred only after the failure plane intersected the upper slope face. By the end of landsliding, the disintegrated slope material formed a talus like deposit at the foot of the slope. The value of initial material cohesion influenced the nature of the landslide deposit and its dimension. Higher material strengths produced smaller landslides, as well as the occurrence of discrete landslide blocks, which originated from the shallow slopes, and became entrained within the finer talus. Stress analysis of the slope failure process clarifies how failure initiates and landsliding evolves, and further constrains the limiting failure criteria that define each simulated material. The local proximity to failure throughout the slope can be tracked during the simulation, revealing that high failure potential (high shear stress relative to mean stress) exists at the toe of the slope immediately following excavation. As material disintegrates near the toe of the slope, high tensile stresses develop in the overlying mass, causing the break

  19. How Strong and Weak Readers Perform on the Developmental Eye Movement Test (DEM): Norms for Latvian School-Aged Children

    ERIC Educational Resources Information Center

    Serdjukova, Jelena; Ekimane, Lasma; Valeinis, Janis; Skilters, Jurgis; Krumina, Gunta

    2017-01-01

    The aim of our study was to determine DEM test performance norms for school-aged children in Latvia, assess how DEM test results correlate with children's reading rates, compare test performance between strong and weak readers. A modified DEM test and a newly developed reading test were administered to 1487 children during a screening survey. Our…

  20. How Strong and Weak Readers Perform on the Developmental Eye Movement Test (DEM): Norms for Latvian School-Aged Children

    ERIC Educational Resources Information Center

    Serdjukova, Jelena; Ekimane, Lasma; Valeinis, Janis; Skilters, Jurgis; Krumina, Gunta

    2017-01-01

    The aim of our study was to determine DEM test performance norms for school-aged children in Latvia, assess how DEM test results correlate with children's reading rates, compare test performance between strong and weak readers. A modified DEM test and a newly developed reading test were administered to 1487 children during a screening survey. Our…

  1. Comments on the MIT Assessment of the Mars One Plan

    NASA Technical Reports Server (NTRS)

    Jones, Harry W.

    2015-01-01

    The MIT assessment of the Mars One mission plan reveals design assumptions that would cause significant difficulties. Growing crops in the crew chamber produces excessive oxygen levels. The assumed in-situ resource utilization (ISRU) equipment has too low a Technology Readiness Level (TRL). The required spare parts cause a large and increasing launch mass logistics burden. The assumed International Space Station (ISS) Environmental Control and Life Support (ECLS) technologies were developed for microgravity and therefore are not suitable for Mars gravity. Growing food requires more mass than sending food from Earth. The large number of spares is due to the relatively low reliability of ECLS and the low TRL of ISRU. The Mars One habitat design is similar to past concepts but does not incorporate current knowledge. The MIT architecture analysis tool for long-term settlements on the Martian surface includes an ECLS system simulation, an ISRU sizing model, and an analysis of required spares. The MIT tool showed the need for separate crop and crew chambers, the large spare parts logistics, that crops require more mass than Earth food, and that more spares are needed if reliability is lower. That ISRU has low TRL and ISS ECLS was designed for microgravity are well known. Interestingly, the results produced by the architecture analysis tool - separate crop chamber, large spares mass, large crop chamber mass, and low reliability requiring more spares - were also well known. A common approach to ECLS architecture analysis is to build a complex model that is intended to be all-inclusive and is hoped will help solve all design problems. Such models can struggle to replicate obvious and well-known results and are often unable to answer unanticipated new questions. A better approach would be to survey the literature for background knowledge and then directly analyze the important problems.

  2. The MIT TEAL Simulations and Visualizations in Electromagnetism

    NASA Astrophysics Data System (ADS)

    Belcher, John

    2007-03-01

    The Technology Enabled Active Learning (TEAL) Project at MIT has developed a broad range of 3D visualizations and simulations to foster student intuition about electromagnetic fields and phenomena (see http://web.mit.edu/8.02t/www/802TEAL3D/). In this talk we discuss the software approaches we use to create these simulations, including Macromedia Shockwave and Java 3D applets for interactive visualization, passive animations created with 3ds max, and the Dynamic Line Integral Convolution (DLIC) method for constructing time dependent representations of the electromagnetic field at close to the resolution of the computer display (Sundquist, 2003). The DLIC method, in particular, is far superior in delineating the spatial and temporal structure of fields as compared to e.g. field line displays or vector field grids. We also report on the use of these visualizations in instruction at the freshmen level. Our strong opinion is that for effective student learning, such visualizations must be embedded in a software framework for their interactive delivery. This ``guided inquiry'' framework is essential to influence and optimize what students take away from the visualizations. In our current research, we are delivering our visualizations using a commercial package, Addison Wesley's MasteringPhysics (MP), although any guided inquiry delivery system such as MP will be able to interact with our simulation software. We have released our Java 3D simulation software as open source with a liberal open source license (see http://jlearn.mit.edu/tealsim/ ), with support from the Davis Educational Foundation.

  3. Research in Boron Neutron Capture Therapy at MIT LABA

    SciTech Connect

    Yanch, J.C.; Shefer, R.E.; Klinkowstein, R.E.; Howard, W.B.; Song, H.; Blackburn, B.; Binello, E.

    1997-02-01

    A 4.1 MeV tandem electrostatic accelerator designed for research into Boron Neutron Capture Therapy (BNCT) has recently been installed in the MIT Laboratory for Accelerator Beam Applications (LABA). This accelerator uses a very high current switch mode high voltage power supply in conjunction with a multi-cusp negative ion source to supply the multimilliampere current required for clinical BNCT applications. A number of individual research projects aimed at evaluating the potential of this accelerator design as a hospital-based neutron source for radiation therapy of both tumors and rheumatoid arthritis are described here. {copyright} {ital 1997 American Institute of Physics.}

  4. Characteristics of the MIT microwiggler for free electron laser applications

    SciTech Connect

    Catravas, P.; Stoner, R.; Bekefi, G.

    1995-12-31

    We report work on the development of microwiggler technology for free electron laser research. The MIT microwiggler is a pulsed electromagnet with 70 periods of 8.8 mm each which generates a peak on-axis field of 4.2 kG. The wiggler is characterized by extensive tunability. We developed a novel tuning regimen to control 140 degrees of freedom afforded by the individually tunable half periods and achieved an rms spread in the peak amplitudes of 0.08%. This is the lowest attained to date in any sub-cm period wiggler. The microwiggler design and comprehensive measurements of its characteristics will be described.

  5. The MIT-Green Bank (MG) 5 GHz survey

    NASA Technical Reports Server (NTRS)

    Bennett, C. L.; Lawrence, C. R.; Burke, B. F.; Hewitt, J. N.; Mahoney, J.

    1986-01-01

    The catalog yielded by the MIT-Green Bank 5-GHz survey contains 5974 sources with S/N ratio greater than 5; a supplemental catalog contains 3836 possible detections with S/N of less than 5. The reliability of the main list is measured to be about 96 percent, with a completeness of about 95 percent. Flux density errors are a function of flux density. A comparison is presently made of survey sources from the Douglas et al. (1980) 365-MHz Texas survey; spectral indices are computed for coincident sources, and the distribution of spectral indices is discussed.

  6. Incorporating the effect of DEM resolution and accuracy for improved flood inundation mapping

    NASA Astrophysics Data System (ADS)

    Saksena, Siddharth; Merwade, Venkatesh

    2015-11-01

    Topography plays a major role in determining the accuracy of flood inundation areas. However, many areas in the United States and around the world do not have access to high quality topographic data in the form of Digital Elevation Models (DEM). For such areas, an improved understanding of the effects of DEM properties such as horizontal resolution and vertical accuracy on flood inundation maps may eventually lead to improved flood inundation modeling and mapping. This study attempts to relate the errors arising from DEM properties such as spatial resolution and vertical accuracy to flood inundation maps, and then use this relationship to create improved flood inundation maps from coarser resolution DEMs with low accuracy. The results from the five stream reaches used in this study show that water surface elevations (WSE) along the stream and the flood inundation area have a linear relationship with both DEM resolution and accuracy. This linear relationship is then used to extrapolate the water surface elevations from coarser resolution DEMs to get water surface elevations corresponding to a finer resolution DEM. Application of this approach show that improved results can be obtained from flood modeling by using coarser and less accurate DEMs, including public domain datasets such as the National Elevation Dataset and Shuttle Radar Topography Mission (SRTM) DEMs. The improvement in the WSE and its application to obtain better flood inundation maps is dependent on the study reach characteristics such as land use, valley shape, reach length and width. Application of the approach presented in this study on more reaches may lead to development of guidelines for flood inundation mapping using coarser resolution and less accurate topographic datasets.

  7. Improving Cartosat-1 DEM accuracy using synthetic stereo pair and triplet

    NASA Astrophysics Data System (ADS)

    Giribabu, D.; Srinivasa Rao, S.; Krishna Murthy, Y. V. N.

    2013-03-01

    Cartosat-1 is the first Indian Remote Sensing Satellite capable of providing along-track stereo images. Cartosat-1 provides forward stereo images with look angles +26° and -5° with respect to nadir for generating Digital Elevation Models (DEMs), Orthoimages and value added products for various applications. A pitch bias of -21° to the satellite resulted in giving reverse tilt mode stereo pair with look angles of +5° and -26° with respect to nadir. This paper compares DEMs generated using forward, reverse and other possible synthetic stereo pairs for two different types of topographies. Stereo triplet was used to generate DEM for Himalayan mountain topography to overcome the problem of occlusions. For flat to undulating topography it was shown that using Cartosat-1 synthetic stereo pair with look angles of -26° and +26° will produce improved version of DEM. Planimetric and height accuracy (Root Mean Square Error (RMSE)) of less than 2.5 m and 2.95 m respectively were obtained and qualitative analysis shows finer details in comparison with other DEMs. For rugged terrain and steep slopes of Himalayan mountain topography simple stereo pairs may not provide reliable accuracies in DEMs due to occlusions and shadows. Stereo triplet from Cartosat-1 was used to generate DEM for mountainous topography. This DEM shows better reconstruction of elevation model even at occluded region when compared with simple stereo pair based DEM. Planimetric and height accuracy (RMSE) of nearly 3 m were obtained and qualitative analysis shows reduction of outliers at occluded region.

  8. Heteronukleare Spinentkopplung unter dem Einfluß thermischer Bewegungen

    NASA Astrophysics Data System (ADS)

    Ernst, H.; Fenzke, D.; Pfeifer, H.

    Unter der Annahme magnetischer Dipol-IS-Wechselwirkung wird eine Theorie der heteronuklearen Spinentkopplung für kurze Korrelationszeiten entwickelt. Diese enthält als Spezialfälle die kernmagnetischen Relaxationsraten im rotierenden und im festen Koordinatensystem sowie die Kreuzpolarisation zwischen den Spins I und S. In Übereinstimmung mit dieser Theorie tritt für die protonenentkoppelte C-13 Resonanz von Butanol, das in einem NaY-Zeolith adsorbiert ist, ein Maximum der Linienbreite als Funktion der Temperatur zwischen - 150°C und + 90°C auf.Translated AbstractHeteronuclear Spin Decoupling in the Presence of Thermal MotionAssuming magnetic dipolar I-S interaction, a general short -correlation time theory is presented which includes as special cases also well-known formulas for relaxation rates in the rotating and laboratory frame and for the cross polarization between I and S spins. In accordance with this theory for the proton-decoupled C-13 resonance of butanol adsorbed in a NaY zeolite, a maximum of the linewidth is observed as a function of temperature between - 150°C and + 90°C.

  9. Dem Retrieval And Ground Motion Monitoring In China

    NASA Astrophysics Data System (ADS)

    Gatti, Guido; Perissin, Daniele; Wang, Teng; Rocca, Fabio

    2010-10-01

    This paper considers the topographic measurement and analysis basing on multi-baseline Synthetic Aperture Radar data. In 2009, the ongoing works were focused on taking advantage of Permanent Scatterers (PS) Interferometry to estimate the terrain elevation and ground motion in not urban contexts. An adapted version of the method, namely Quasi-PS (QPS) technique, has been used in order to exploit the distributed target information. One of the analyzed datasets concerns the mountainous area around Zhangbei, Hebei Province, from which a geocoded Digital Elevation Model (DEM) has been retrieved. Regarding ground motion monitoring, our attention was focalized on two different areas. The first is a small area near the Three Gorges Dam, in which ground deformations have been identified and measured. The second area regards the west part of the municipality of Shanghai, centered on a straight railway. The subsidence in that zone has been measured and the interferometric coherence of the railway has been studied, according to the hypothesis of spatial and temporal stability of this kind of target.

  10. DEM Simulation of Particle Clogging in Fiber Filtration

    NASA Astrophysics Data System (ADS)

    Tao, Ran; Yang, Mengmeng; Li, Shuiqing

    2015-11-01

    The formation of porous particle deposits plays a crucial role in determining the efficiency of filtration process. In this work, an adhesive discrete element method (DEM), in combination with CFD, is developed to dynamically describe these porous deposit structures and the changed flow field between two parallel fibers under the periodic boundary conditions. For the first time, it is clarified that the structures of clogged particles are dependent on both the adhesion parameter (defined as the ratio of interparticle adhesion to particle inertia) and the Stokes number (as an index of impaction efficiency). The relationship between the pressure-drop gradient and the coordination number along the filtration time is explored, which can be used to quantitatively classify the different filtration regimes, i.e., clean filter stage, clogging stage and cake filtration stage. Finally, we investigate the influence of the fiber separation distance on the particle clogging behavior, which affects the collecting efficiency of the fibers significantly. The results suggest that changing the arrangement of fibers can improve the filter performance. This work has been funded by the National Key Basic Research and Development Program (2013CB228506).

  11. Evaluation of DEM generation accuracy from UAS imagery

    NASA Astrophysics Data System (ADS)

    Santise, M.; Fornari, M.; Forlani, G.; Roncella, R.

    2014-06-01

    The growing use of UAS platform for aerial photogrammetry comes with a new family of Computer Vision highly automated processing software expressly built to manage the peculiar characteristics of these blocks of images. It is of interest to photogrammetrist and professionals, therefore, to find out whether the image orientation and DSM generation methods implemented in such software are reliable and the DSMs and orthophotos are accurate. On a more general basis, it is interesting to figure out whether it is still worth applying the standard rules of aerial photogrammetry to the case of drones, achieving the same inner strength and the same accuracies as well. With such goals in mind, a test area has been set up at the University Campus in Parma. A large number of ground points has been measured on natural as well as signalized points, to provide a comprehensive test field, to check the accuracy performance of different UAS systems. In the test area, points both at ground-level and features on the buildings roofs were measured, in order to obtain a distributed support also altimetrically. Control points were set on different types of surfaces (buildings, asphalt, target, fields of grass and bumps); break lines, were also employed. The paper presents the results of a comparison between two different surveys for DEM (Digital Elevation Model) generation, performed at 70 m and 140 m flying height, using a Falcon 8 UAS.

  12. Applying the Artificial Neural Network to Predict the Soil Responses in the DEM Simulation

    NASA Astrophysics Data System (ADS)

    Li, Z.; Chow, J. K.; Wang, Y. H.

    2017-06-01

    This paper aims to bridge the soil properties and the soil response in the discrete element method (DEM) simulation using the artificial neural network (ANN). The network was designed to output the stress-strain-volumetric response from inputting the soil properties. 31 biaxial shearing tests with varying soil parameters were generated using the DEM simulations. Based on these 31 training samples, a three-layer neural network was established. 2 extra samples were generated to examine the validity of the network, and the predicted curves using the ANN were well matched with those from the DEM simulations. Overall, the ANN was found promising in effectively modelling the soil behaviour.

  13. Morphological changes at Mt. Etna detected by TanDEM-X

    NASA Astrophysics Data System (ADS)

    Wegmuller, Urs; Bonforte, Alessandro; De Beni, Emanuela; Guglielmino, Francesco; Strozzi, Tazio

    2014-05-01

    We produced a DEM of the Mt. Etna volcano using TanDEM-X data collected on October 9, 2012. The TanDEM-X data were acquired in bistatic mode with TSX as master sensor and TDX as receive only sensor. The pre-existing SRTM DEM was used for geometrical reference (geocoding, initial height model, large scale reference). The interferogram was computed with 4 looks in range and 4 looks in azimuth. After compensation of the SRTM heights, the differential TanDEM-X interferogram looked overall quite flat but showed local deviations related to noise (e.g. over the sea), topographic effects related to the low resolution of the SRTM DEM, and deviations related to actual changes of the topography, as observed in the Mount Etna peak region. After phase unwrapping, addressed with a minimum-cost flow algorithm and slight spatial filtering, the unwrapped phases were converted to relative heights. In order to move to absolute heights the SRTM height reference was used under the assumption that the deviation from the SRTM DEM is zero at large scale and without any linear trend. Finally, the height model was resampled into geographical coordinates. In the framework of the MED-SUV project, and thanks to the availability of a dense GPS network of more than 100 benchmarks periodically measured by INGV_OE, the TanDEM-X model has been validated. By computing the difference of the elevations provided by TanDEM-X with those measured by GPS we obtained a mean difference of 0.7 m and a standard deviation of 5.2 m. These values are biased by a few GPS benchmarks located in steep areas unfavorable illuminated by the radar. Without considerations of the two more unfavorable GPS stations, the height mean difference and a standard deviation are 0.6 m and 4.3 m respectively. We also performed correlation analyses of the height differences with respect to topography, latitude and longitude and we could exclude any elevation-related errors or geometrical ramp distortions. In the following, we compared

  14. Helicobacter sp. MIT 01-6451 infection during fetal and neonatal life in laboratory mice.

    PubMed

    Yamanaka, Hitoki; Nakanishi, Tai; Takagi, Toshikazu; Ohsawa, Makiko; Kubo, Noriaki; Yamamoto, Naoto; Takemoto, Takahira; Ohsawa, Kazutaka

    2015-01-01

    Helicobacter sp. MIT 01-6451 has been detected in SPF mice kept in Japan. To characterize strain MIT 01-6451, its infection route during fetal and neonatal life and effects on pregnancy were investigated using immunocompetent and immunodeficient mouse strains (BALB/c, C57BL/6, and SCID). MIT 01-6451 was detected in the uterus, vagina, and mammary glands of 50% of infected SCID mice, whereas these tissues were all negative in immunocompetent mice. No fetal infections with MIT 01-6451 were detected at 16-18 days after pregnancy in any mouse strain. In newborn mice, MIT 01-6451 was detected in intestinal tissue of C57BL/6 and SCID mice at 9-11 days after birth, but not in BALB/c mice. The IgA and IgG titers to MIT 01-6451 in sera of C57BL/6 female mice were significantly lower than those of BALB/c mice. Although no significant differences in the number of newborns per litter were observed between MIT 01-6451-infected and MIT 01-6451-free dams, the birth rate was lower in infected SCID mice than in control SCID mice. The present results indicated that MIT 01-6451 infects newborn mice after birth rather than by vertical transmission to the fetus via the placenta and that MIT 01-6451 infection shows opportunistically negative effects on the birth rate. In addition, the maternal immune response may affect infection of newborn mice with MIT 01-6451 through breast milk.

  15. Helicobacter sp. MIT 01-6451 infection during fetal and neonatal life in laboratory mice

    PubMed Central

    Yamanaka, Hitoki; Nakanishi, Tai; Takagi, Toshikazu; Ohsawa, Makiko; Kubo, Noriaki; Yamamoto, Naoto; Takemoto, Takahira; Ohsawa, Kazutaka

    2015-01-01

    Helicobacter sp. MIT 01-6451 has been detected in SPF mice kept in Japan. To characterize strain MIT 01-6451, its infection route during fetal and neonatal life and effects on pregnancy were investigated using immunocompetent and immunodeficient mouse strains (BALB/c, C57BL/6, and SCID). MIT 01-6451 was detected in the uterus, vagina, and mammary glands of 50% of infected SCID mice, whereas these tissues were all negative in immunocompetent mice. No fetal infections with MIT 01-6451 were detected at 16–18 days after pregnancy in any mouse strain. In newborn mice, MIT 01-6451 was detected in intestinal tissue of C57BL/6 and SCID mice at 9–11 days after birth, but not in BALB/c mice. The IgA and IgG titers to MIT 01-6451 in sera of C57BL/6 female mice were significantly lower than those of BALB/c mice. Although no significant differences in the number of newborns per litter were observed between MIT 01-6451-infected and MIT 01-6451-free dams, the birth rate was lower in infected SCID mice than in control SCID mice. The present results indicated that MIT 01-6451 infects newborn mice after birth rather than by vertical transmission to the fetus via the placenta and that MIT 01-6451 infection shows opportunistically negative effects on the birth rate. In addition, the maternal immune response may affect infection of newborn mice with MIT 01-6451 through breast milk. PMID:26134357

  16. Educational Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, Paul; Thomas, Paul

    2004-11-01

    At the MIT PSFC student and staff volunteers work together to increase the public's knowledge of fusion science and plasma technology. Seeking to generate excitement in young people about science and engineering, the PSFC hosts a number of educational outreach activities and tours throughout the year, including Middle and High School Outreach Days. The PSFC also has an in-school science demonstration program on the theme of magnetism. As ''Mr. Magnet'' Technical Supervisor Paul Thomas brings a truck-load of hands-on demonstrations to K-12 schools, challenging students to help him with experiments. While teaching fundamentals of magnetism and electricity he shows that science is fun for all, and that any student can have a career in science. This year he taught at 75 schools and other events, reaching 30,000 teachers and students. He has expanded his teaching to include an interactive demonstration of plasma, encouraging participants to investigate plasma properties with audiovisual, electromagnetic, and spectroscopic techniques. The PSFC's continuing involvement with the MIT Museum and the Boston Museum of Science also helps familiarize the public with the fourth state of matter.

  17. Quark orbital angular momentum in the MIT bag model

    NASA Astrophysics Data System (ADS)

    Courtoy, A.; Miramontes, A. S.

    2017-01-01

    We present the results for the generalized transverse momentum distribution related to quark orbital angular momentum, i.e., F14, in the MIT bag model. This model has been modified to include the Peierls-Yoccoz projection to restore translational invariance. Such a modification allows us to fulfil more satisfactorily basic sum rules that would otherwise be less elegantly carried out with the original version. Using the same model, we have calculated the twist-3 generalized parton distribution (GPD) that corresponds to orbital angular momentum à la Ji, through the Penttinen-Polyakov-Shuvaev-Strikman sum rule. Recently, a new relation between the two definitions of the quark orbital angular momentum at the density level has been proposed, which we illustrate here within the model. The sum rule is fulfilled. Still within the framework of the MIT bag model, we analyze the Wandzura-Wilczek expression for the GPD of interest. The genuine quark-gluon contribution is evaluated directly thanks to the equation of motion of the bag, which allows for a direct control of the kinematical contributions to the twist-3 GPD.

  18. TecDEM: A MATLAB based toolbox for tectonic geomorphology, Part 1: Drainage network preprocessing and stream profile analysis

    NASA Astrophysics Data System (ADS)

    Shahzad, Faisal; Gloaguen, Richard

    2011-02-01

    We present TecDEM, a software shell implemented in MATLAB that applies tectonic geomorphologic tasks to digital elevation models (DEMs). The first part of this paper series describes drainage partitioning schemes and stream profile analysis. The graphical user interface of TecDEM provides several options: determining flow directions, stream vectorization, watershed delineation, Strahler order labeling, stream profile generation, knickpoints selection, Concavity, Steepness and Hack indices calculations. The knickpoints along selected streams as well as stream profile analysis, and Hack index per stream profile are computed using a semi-automatic method. TecDEM was used to extract and investigate the stream profiles in the Kaghan Valley (Northern Pakistan). Our interpretations of the TecDEM results correlate well with previous tectonic evolution models for this region. TecDEM is designed to assist geoscientists in applying complex tectonic geomorphology tasks to global DEM data.

  19. What is the effect of LiDAR-derived DEM resolution on large-scale watershed model results?

    SciTech Connect

    Ping Yang; Daniel B. Ames; Andre Fonseca; Danny Anderson; Rupesh Shrestha; Nancy F. Glenn; Yang Cao

    2014-08-01

    This paper examines the effect of raster cell size on hydrographic feature extraction and hydrological modeling using LiDAR derived DEMs. LiDAR datasets for three experimental watersheds were converted to DEMs at various cell sizes. Watershed boundaries and stream networks were delineated from each DEM and were compared to reference data. Hydrological simulations were conducted and the outputs were compared. Smaller cell size DEMs consistently resulted in less difference between DEM-delineated features and reference data. However, minor differences been found between streamflow simulations resulted for a lumped watershed model run at daily simulations aggregated at an annual average. These findings indicate that while higher resolution DEM grids may result in more accurate representation of terrain characteristics, such variations do not necessarily improve watershed scale simulation modeling. Hence the additional expense of generating high resolution DEM's for the purpose of watershed modeling at daily or longer time steps may not be warranted.

  20. IPY: An excellent opportunity to improve Arctic DEMs and document today's Arctic for future generations

    NASA Astrophysics Data System (ADS)

    Nolan, M.

    2003-12-01

    Digital Elevation Models (DEMs) are an essential resource for any field or modeling study in the terrestrial Arctic, yet the DEMs available there are currently the worst on the planet. Efforts in the past decade have led to the acquisition of new DEMs for the entire Antarctic continent (Radarsat Antarctic Mapping Project, RAMP) and for nearly all of the planet within +/- 60 degrees latitude (Space Shuttle Radar Topography Mission, SRTM). Thus, the U.S. Arctic is left with 1:63,360 maps made during the IGY times, which does not meet the USGS' own standards for accuracy. Other countries are left in similar circumstances, with DEMs created from paper maps with usually no better than 1:50,000 scale, and there is as yet no central circum-polar clearinghouse for such DEMs. And because nearly all of these DEMs were created by digitizing paper base maps, most contain artifacts of the digitizing process that further reduce their quality. It could be argued that DEMs of the polar regions of the planet Mars are more accurate, consistent, and easily available than those from the Earth's Arctic. Only an organized international effort could possibly manage such a data collection task, and the project seems well suited to the goals of the International Polar Year. Perhaps being last in line for new DEMs is actually beneficial in this case, as technological improvements have led to new acquisition systems that are more accurate than those used in SRTM and RAMP. For example, airborne synthetic aperture radar (SAR) interferometry has demonstrated the capability to acquire DEMs with 5 meter postings, 1 cm vertical resolution, and 2 m vertical accuracies, in addition to an orthorectified radar backscatter image at 2.5 meter postings; compare this with the 60m x 90m posting available currently and no associated orthoimagery. That is, for the price of an Arctic DEM, we would also get a picture of the Arctic at 2.5 meter resolution, and this picture can be merged with color Landsat to

  1. Automated sinkhole detection using a DEM subsetting technique and fill tools at Mammoth Cave National Park

    NASA Astrophysics Data System (ADS)

    Wall, J.; Bohnenstiehl, D. R.; Levine, N. S.

    2013-12-01

    An automated workflow for sinkhole detection is developed using Light Detection and Ranging (Lidar) data from Mammoth Cave National Park (MACA). While the park is known to sit within a karst formation, the generally dense canopy cover and the size of the park (~53,000 acres) creates issues for sinkhole inventorying. Lidar provides a useful remote sensing technology for peering beneath the canopy in hard to reach areas of the park. In order to detect sinkholes, a subsetting technique is used to interpolate a Digital Elevation Model (DEM) thereby reducing edge effects. For each subset, standard GIS fill tools are used to fill depressions within the DEM. The initial DEM is then subtracted from the filled DEM resulting in detected depressions or sinkholes. Resulting depressions are then described in terms of size and geospatial trend.

  2. M.I.T. and the Federal Government. An Examination of the Effects of Government Regulation and Research Support on Selected Parts of M.I.T.

    ERIC Educational Resources Information Center

    Garvin, David

    A self-study was undertaken at the Massachusetts Institute of Technology (M.I.T.) to examine the impact of the federal government on it. M.I.T. is a large institution with an enrollment of 8,000, a faculty of 950, and a total teaching staff of 1,700. Of its operating expenses by far the largest source of funds in recent years has been sponsored…

  3. Mobile-IT Education (MIT.EDU): M-Learning Applications for Classroom Settings

    ERIC Educational Resources Information Center

    Sung, M.; Gips, J.; Eagle, N.; Madan, A.; Caneel, R.; DeVaul, R.; Bonsen, J.; Pentland, A.

    2005-01-01

    In this paper, we describe the Mobile-IT Education (MIT.EDU) system, which demonstrates the potential of using a distributed mobile device architecture for rapid prototyping of wireless mobile multi-user applications for use in classroom settings. MIT.EDU is a stable, accessible system that combines inexpensive, commodity hardware, a flexible…

  4. MIT domain of Vps4 is a Ca2+-dependent phosphoinositide-binding domain.

    PubMed

    Iwaya, Naoko; Takasu, Hirotoshi; Goda, Natsuko; Shirakawa, Masahiro; Tanaka, Toshiki; Hamada, Daizo; Hiroaki, Hidekazu

    2013-05-01

    The microtubule interacting and trafficking (MIT) domain is a small protein module that is conserved in proteins of diverged function, such as Vps4, spastin and sorting nexin 15 (SNX15). The molecular function of the MIT domain is protein-protein interaction, in which the domain recognizes peptides containing MIT-interacting motifs. Recently, we identified an evolutionarily related domain, 'variant' MIT domain at the N-terminal region of the microtubule severing enzyme katanin p60. We found that the domain was responsible for binding to microtubules and Ca(2+). Here, we have examined whether the authentic MIT domains also bind Ca(2+). We found that the loop between the first and second α-helices of the MIT domain binds a Ca(2+) ion. Furthermore, the MIT domains derived from Vps4b and SNX15a showed phosphoinositide-binding activities in a Ca(2+)-dependent manner. We propose that the MIT domain is a novel membrane-associating domain involved in endosomal trafficking.

  5. Scratch that: MIT's Mitchel Resnick Says Kids Should Do It for Themselves

    ERIC Educational Resources Information Center

    Traylor, Scott

    2008-01-01

    Mitchel Resnick is a researcher, inventor, and professor at MIT's Media Laboratory in Cambridge, MA, and the founder of the Lifelong Kindergarten Group at MIT. He is the lead innovator behind many cutting-edge learning technologies and projects for children, including the Computer Clubhouse, PicoCrickets, and the wildly successful consumer…

  6. MIT(1), a black mamba toxin with a new and highly potent activity on intestinal contraction.

    PubMed

    Schweitz, H; Pacaud, P; Diochot, S; Moinier, D; Lazdunski, M

    1999-11-19

    Mamba intestinal toxin (MIT(1)) isolated from Dendroaspis polylepis venom is a 81 amino acid polypeptide cross-linked by five disulphide bridges. MIT(1) has a very potent action on guinea-pig intestinal contractility. MIT(1) (1 nM) potently contracts longitudinal ileal muscle and distal colon, and this contraction is equivalent to that of 40 mM K(+). Conversely MIT(1) relaxes proximal colon again as potently as 40 mM K(+). The MIT(1)-induced effects are antagonised by tetrodotoxin (1 microM) in proximal and distal colon but not in longitudinal ileum. The MIT(1)-induced relaxation of the proximal colon is reversibly inhibited by the NO synthase inhibitor L-NAME (200 microM). (125)I-labelled MIT(1) binds with a very high affinity to both ileum and brain membranes (K(d)=1.3 pM and 0.9 pM, and B(max)=30 fmol/mg and 26 fmol/mg, respectively). MIT(1) is a very highly selective toxin for a receptor present both in the CNS and in the smooth muscle and which might be an as yet unidentified K(+) channel.

  7. Scratch that: MIT's Mitchel Resnick Says Kids Should Do It for Themselves

    ERIC Educational Resources Information Center

    Traylor, Scott

    2008-01-01

    Mitchel Resnick is a researcher, inventor, and professor at MIT's Media Laboratory in Cambridge, MA, and the founder of the Lifelong Kindergarten Group at MIT. He is the lead innovator behind many cutting-edge learning technologies and projects for children, including the Computer Clubhouse, PicoCrickets, and the wildly successful consumer…

  8. Mobile-IT Education (MIT.EDU): M-Learning Applications for Classroom Settings

    ERIC Educational Resources Information Center

    Sung, M.; Gips, J.; Eagle, N.; Madan, A.; Caneel, R.; DeVaul, R.; Bonsen, J.; Pentland, A.

    2005-01-01

    In this paper, we describe the Mobile-IT Education (MIT.EDU) system, which demonstrates the potential of using a distributed mobile device architecture for rapid prototyping of wireless mobile multi-user applications for use in classroom settings. MIT.EDU is a stable, accessible system that combines inexpensive, commodity hardware, a flexible…

  9. Assessing International Product Design and Development Graduate Courses: The MIT-Portugal Program

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Silva, Arlindo

    2010-01-01

    The Product Design and Development (PDD) course is part of the graduate curriculum in the Engineering Design and Advanced Manufacturing (EDAM) study in the MIT-Portugal Program. The research participants included about 110 students from MIT, EDAM, and two universities in Portugal, Instituto Superior Técnico-Universidade Técnica de Lisboa (IST) and…

  10. Glacier Volume Change Estimation Using Time Series of Improved Aster Dems

    NASA Astrophysics Data System (ADS)

    Girod, Luc; Nuth, Christopher; Kääb, Andreas

    2016-06-01

    Volume change data is critical to the understanding of glacier response to climate change. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system embarked on the Terra (EOS AM-1) satellite has been a unique source of systematic stereoscopic images covering the whole globe at 15m resolution and at a consistent quality for over 15 years. While satellite stereo sensors with significantly improved radiometric and spatial resolution are available to date, the potential of ASTER data lies in its long consistent time series that is unrivaled, though not fully exploited for change analysis due to lack of data accuracy and precision. Here, we developed an improved method for ASTER DEM generation and implemented it in the open source photogrammetric library and software suite MicMac. The method relies on the computation of a rational polynomial coefficients (RPC) model and the detection and correction of cross-track sensor jitter in order to compute DEMs. ASTER data are strongly affected by attitude jitter, mainly of approximately 4 km and 30 km wavelength, and improving the generation of ASTER DEMs requires removal of this effect. Our sensor modeling does not require ground control points and allows thus potentially for the automatic processing of large data volumes. As a proof of concept, we chose a set of glaciers with reference DEMs available to assess the quality of our measurements. We use time series of ASTER scenes from which we extracted DEMs with a ground sampling distance of 15m. Our method directly measures and accounts for the cross-track component of jitter so that the resulting DEMs are not contaminated by this process. Since the along-track component of jitter has the same direction as the stereo parallaxes, the two cannot be separated and the elevations extracted are thus contaminated by along-track jitter. Initial tests reveal no clear relation between the cross-track and along-track components so that the latter seems not to be

  11. The topographic grain concept in DEM-based geomorphometric mapping

    NASA Astrophysics Data System (ADS)

    Józsa, Edina

    2016-04-01

    A common drawback of geomorphological analyses based on digital elevation datasets is the definition of search window size for the derivation of morphometric variables. The fixed-size neighbourhood determines the scale of the analysis and mapping, which can lead to the generalization of smaller surface details or the elimination of larger landform elements. The methods of DEM-based geomorphometric mapping are constantly developing into the direction of multi-scale landform delineation, but the optimal threshold for search window size is still a limiting factor. A possible way to determine the suitable value for the parameter is to consider the topographic grain principle (Wood, W. F. - Snell, J. B. 1960, Pike, R. J. et al. 1989). The calculation is implemented as a bash shell script for GRASS GIS to determine the optimal threshold for the r.geomorphon module. The approach relies on the potential of the topographic grain to detect the characteristic local ridgeline-to-channel spacing. By calculating the relative relief values with nested neighbourhood matrices it is possible to define a break-point where the increase rate of local relief encountered by the sample is significantly reducing. The geomorphons approach (Jasiewicz, J. - Stepinski, T. F. 2013) is a cell-based DEM classification method for the identification of landform elements at a broad range of scales by using line-of-sight technique. The landforms larger than the maximum lookup distance are broken down to smaller elements therefore the threshold needs to be set for a relatively large value. On the contrary, the computational requirements and the size of the study sites determine the upper limit for the value. Therefore the aim was to create a tool that would help to determine the optimal parameter for r.geomorphon tool. As a result it would be possible to produce more objective and consistent maps with achieving the full efficiency of this mapping technique. For the thorough analysis on the

  12. ASTER Global DEM contribution to GEOSS demonstrates open data sharing

    NASA Astrophysics Data System (ADS)

    Sohre, T.; Duda, K. A.; Meyer, D. J.; Behnke, J.; Nasa Esdis Lp Daac

    2010-12-01

    across all the GEOSS Societal Benefit areas was shown. The release of the global tiled research-grade DEM resulted in a significant increase in demand for ASTER elevation models, and increased awareness of related products. No cost access to these data has also promoted new applications of remotely sensed data, increasing their use across the full range of the GEOSS societal benefit areas. In addition, the simplified data access and greatly expanded pool of users resulted in a number of suggestions from researchers in many disciplines for possible enhancements to future versions of the ASTER GDEM. The broad distribution of the product can be directly attributed to the adoption of fundamental GEOSS data sharing principles, which are directed toward expanded access by minimizing time delay and cost, thus facilitating data use for education, research, and a range of other applications. The ASTER GDEM demonstrated the need and user demand for an improved global DEM product as well as the added benefit of not only “full and open” distribution, but “free and open” distribution.

  13. DEM simulation of granular flows in a centrifugal acceleration field

    NASA Astrophysics Data System (ADS)

    Cabrera, Miguel Angel; Peng, Chong; Wu, Wei

    2017-04-01

    The main purpose of mass-flow experimental models is abstracting distinctive features of natural granular flows, and allow its systematic study in the laboratory. In this process, particle size, space, time, and stress scales must be considered for the proper representation of specific phenomena [5]. One of the most challenging tasks in small scale models, is matching the range of stresses and strains among the particle and fluid media observed in a field event. Centrifuge modelling offers an alternative to upscale all gravity-driven processes, and it has been recently employed in the simulation of granular flows [1, 2, 3, 6, 7]. Centrifuge scaling principles are presented in Ref. [4], collecting a wide spectrum of static and dynamic models. However, for the case of kinematic processes, the non-uniformity of the centrifugal acceleration field plays a major role (i.e., Coriolis and inertial effects). In this work, we discuss a general formulation for the centrifugal acceleration field, implemented in a discrete element model framework (DEM), and validated with centrifuge experimental results. Conventional DEM simulations relate the volumetric forces as a function of the gravitational force Gp = mpg. However, in the local coordinate system of a rotating centrifuge model, the cylindrical centrifugal acceleration field needs to be included. In this rotating system, the centrifugal acceleration of a particle depends on the rotating speed of the centrifuge, as well as the position and speed of the particle in the rotating model. Therefore, we obtain the formulation of centrifugal acceleration field by coordinate transformation. The numerical model is validated with a series of centrifuge experiments of monodispersed glass beads, flowing down an inclined plane at different acceleration levels and slope angles. Further discussion leads to the numerical parameterization necessary for simulating equivalent granular flows under an augmented acceleration field. The premise of

  14. HELI-DEM portal for geo-processing services

    NASA Astrophysics Data System (ADS)

    Cannata, Massimiliano; Antonovic, Milan; Molinari, Monia

    2014-05-01

    HELI-DEM (Helvetia-Italy Digital Elevation Model) is a project developed in the framework of Italy/Switzerland Operational Programme for Trans-frontier Cooperation 2007-2013 whose major aim is to create a unified digital terrain model that includes the alpine and sub-alpine areas between Italy and Switzerland. The partners of the project are: Lombardy Region, Piedmont Region, Polytechnic of Milan, Polytechnic of Turin and Fondazione Politecnico from Italy; Institute of Earth Sciences (SUPSI) from Switzerland. The digital terrain model has been produced by integrating and validating the different elevation data available for the areas of interest, characterized by different reference frame, resolutions and accuracies: DHM at 25 m resolution from Swisstopo, DTM at 20 m resolution from Lombardy Region, DTM at 5 m resolution from Piedmont Region and DTM LiDAR PST-A at about 1 m resolution, that covers the main river bed areas and is produced by the Italian Ministry of the Environment. Further results of the project are: the generation of a unique Italian Swiss geoid with an accuracy of few centimeters (Gilardoni et al. 2012); the establishment of a GNSS permanent network, prototype of a transnational positioning service; the development of a geo-portal, entirely based on open source technologies and open standards, which provides the cross-border DTM and offers some capabilities of analysis and processing through the Internet. With this talk, the authors want to present the main steps of the project with a focus on the HELI-DEM geo-portal development carried out by the Institute of Earth Sciences, which is the access point to the DTM outputted from the project. The portal, accessible at http://geoservice.ist.supsi.ch/helidem, is a demonstration of open source technologies combined for providing access to geospatial functionalities to wide non GIS expert public. In fact, the system is entirely developed using only Open Standards and Free and Open Source Software (FOSS

  15. 2D DEM model of sand transport with wind interaction

    NASA Astrophysics Data System (ADS)

    Oger, L.; Valance, A.

    2013-06-01

    The advance of the dunes in the desert is a threat to the life of the local people. The dunes invade houses, agricultural land and perturb the circulation on the roads. It is therefore very important to understand the mechanism of sand transport in order to fight against desertification. Saltation in which sand grains are propelled by the wind along the surface in short hops, is the primary mode of blown sand movement [1]. The saltating grains are very energetic and when impact a sand surface, they rebound and consequently eject other particles from the sand bed. The ejected grains, called reptating grains, contribute to the augmentation of the sand flux. Some of them can be promoted to the saltation motion. We use a mechanical model based on the Discrete Element Method to study successive collisions of incident energetic beads with granular packing in the context of Aeolian saltation transport. We investigate the collision process for the case where the incident bead and those from the packing have identical mechanical properties. We analyze the features of the consecutive collision processes made by the transport of the saltating disks by a wind in which its profile is obtained from the counter-interaction between air flow and grain flows. We used a molecular dynamics method known as DEM (soft Discrete Element Method) with a initial static packing of 20000 2D particles. The dilation of the upper surface due to the consecutive collisions is responsible for maintaining the flow at a given energy input due to the wind.

  16. Modelling of Singapore's topographic transformation based on DEMs

    NASA Astrophysics Data System (ADS)

    Wang, Tao; Belle, Iris; Hassler, Uta

    2015-02-01

    Singapore's topography has been heavily transformed by industrialization and urbanization processes. To investigate topographic changes and evaluate soil mass flows, historical topographic maps of 1924 and 2012 were employed, and basic topographic features were vectorized. Digital elevation models (DEMs) for the two years were reconstructed based on vector features. Corresponding slope maps, a surface difference map and a scatter plot of elevation changes were generated and used to quantify and categorize the nature of the topographic transformation. The surface difference map is aggregated into five main categories of changes: (1) areas without significant height changes, (2) lowered-down areas where hill ranges were cut down, (3) raised-up areas where valleys and swamps were filled in, (4) reclaimed areas from the sea, and (5) new water-covered areas. Considering spatial proximity and configurations of different types of changes, topographic transformation can be differentiated as either creating inland flat areas or reclaiming new land from the sea. Typical topographic changes are discussed in the context of Singapore's urbanization processes. The two slope maps and elevation histograms show that generally, the topographic surface of Singapore has become flatter and lower since 1924. More than 89% of height changes have happened within a range of 20 m and 95% have been below 40 m. Because of differences in land surveying and map drawing methods, uncertainties and inaccuracies inherent in the 1924 topographic maps are discussed in detail. In this work, a modified version of a traditional scatter plot is used to present height transformation patterns intuitively. This method of deriving categorical maps of topographical changes from a surface difference map can be used in similar studies to qualitatively interpret transformation. Slope maps and histograms were also used jointly to reveal additional patterns of topographic change.

  17. An improved method to represent DEM uncertainty in glacial lake outburst flood propagation using stochastic simulations

    NASA Astrophysics Data System (ADS)

    Watson, Cameron S.; Carrivick, Jonathan; Quincey, Duncan

    2015-10-01

    Modelling glacial lake outburst floods (GLOFs) or 'jökulhlaups', necessarily involves the propagation of large and often stochastic uncertainties throughout the source to impact process chain. Since flood routing is primarily a function of underlying topography, communication of digital elevation model (DEM) uncertainty should accompany such modelling efforts. Here, a new stochastic first-pass assessment technique was evaluated against an existing GIS-based model and an existing 1D hydrodynamic model, using three DEMs with different spatial resolution. The analysis revealed the effect of DEM uncertainty and model choice on several flood parameters and on the prediction of socio-economic impacts. Our new model, which we call MC-LCP (Monte Carlo Least Cost Path) and which is distributed in the supplementary information, demonstrated enhanced 'stability' when compared to the two existing methods, and this 'stability' was independent of DEM choice. The MC-LCP model outputs an uncertainty continuum within its extent, from which relative socio-economic risk can be evaluated. In a comparison of all DEM and model combinations, the Shuttle Radar Topography Mission (SRTM) DEM exhibited fewer artefacts compared to those with the Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM), and were comparable to those with a finer resolution Advanced Land Observing Satellite Panchromatic Remote-sensing Instrument for Stereo Mapping (ALOS PRISM) derived DEM. Overall, we contend that the variability we find between flood routing model results suggests that consideration of DEM uncertainty and pre-processing methods is important when assessing flow routing and when evaluating potential socio-economic implications of a GLOF event. Incorporation of a stochastic variable provides an illustration of uncertainty that is important when modelling and communicating assessments of an inherently complex process.

  18. Uncertainty of SWAT model at different DEM resolutions in a large mountainous watershed.

    PubMed

    Zhang, Peipei; Liu, Ruimin; Bao, Yimeng; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

    2014-04-15

    The objective of this study was to enhance understanding of the sensitivity of the SWAT model to the resolutions of Digital Elevation Models (DEMs) based on the analysis of multiple evaluation indicators. The Xiangxi River, a large tributary of Three Gorges Reservoir in China, was selected as the study area. A range of 17 DEM spatial resolutions, from 30 to 1000 m, was examined, and the annual and monthly model outputs based on each resolution were compared. The following results were obtained: (i) sediment yield was greatly affected by DEM resolution; (ii) the prediction of dissolved oxygen load was significantly affected by DEM resolutions coarser than 500 m; (iii) Total Nitrogen (TN) load was not greatly affected by the DEM resolution; (iv) Nitrate Nitrogen (NO₃-N) and Total Phosphorus (TP) loads were slightly affected by the DEM resolution; and (v) flow and Ammonia Nitrogen (NH₄-N) load were essentially unaffected by the DEM resolution. The flow and dissolved oxygen load decreased more significantly in the dry season than in the wet and normal seasons. Excluding flow and dissolved oxygen, the uncertainties of the other Hydrology/Non-point Source (H/NPS) pollution indicators were greater in the wet season than in the dry and normal seasons. Considering the temporal distribution uncertainties, the optimal DEM resolutions for flow was 30-200 m, for sediment and TP was 30-100 m, for dissolved oxygen and NO₃-N was 30-300 m, for NH₄-N was 30 to 70 m and for TN was 30-150 m.

  19. Monitoring lava dome changes by means of differential DEMs from TanDEM-X interferometry: Examples from Merapi, Indonesia and Volcán de Colima, Mexico

    NASA Astrophysics Data System (ADS)

    Kubanek, J.; Westerhaus, M.; Heck, B.

    2013-12-01

    Estimating the amount of erupted material during a volcanic crisis is one of the major challenges in volcano research. One way to do this and to discriminate between juvenile and non-juvenile fraction is to assess topographic changes before and after an eruption while using area-wide 3D data. LiDAR or other airborne systems may be a good source, but the recording fails when clouds due to volcanic activity obstruct the sight. In addition, costs as well as logistics are high for local observatories. When dealing with dome-building volcanoes, acquiring the data gets further complicated. As the volcano dome can change rapidly in active phases, it is nearly impossible to collect data at the right time. However, when dealing with gross volume change estimates, at least two data sets - taken directly before and after the eruption - are essential. The innovative German Earth observation mission TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is of great importance to overcome some of these problems. The two almost identical radar satellites TerraSAR-X and TanDEM-X fly in a close formation, thus recording images of the same place on the Earth surface at the same time (bistatic mode). As the radar signal penetrates clouds, digital elevation models (DEMs) of the area of investigation can be generated without problems even with cloud cover. A time series analysis of the differential DEMs therefore opens the possibility to assess volume changes at active lava domes. We choose Merapi in Indonesia and Volcán de Colima in Mexico as test sites. Both volcanoes reside in a state of long term effusive eruption, interrupted every few years by phases of dome destruction, generation of pyroclastic flows and deposition of volcanic material. The availability of extensive ground truth data for both test sites further enables to validate the spaceborne data and results. Here, we analyze lava dome changes due to the hazardous Merapi 2010 eruption. We show a series of DEMs

  20. Estimating Canopy Height of a Temperate Forest from TanDEM-X and LVIS Data

    NASA Astrophysics Data System (ADS)

    Qi, W.; Dubayah, R.; Kugler, F.

    2014-12-01

    The recently launched TanDEM-X mission is the first single-pass polarimetric interferometer in space allowing global estimation of forest parameters without any temporal decorrelation. This study investigates the potential of single-polarized TanDEM-X data for forest height inversion and structure characterization. For this purpose, a temperate forest - Hubbard Brook Experimental Forest (HBEF) in New Hampshire is chosen for experiment. Stripmap-mode HH-polarized TanDEM-X bistatic data (with resolution at 3 m) acquired at different baselines was used. LVIS data was applied to remove the ground phase component of the TanDEM-X interferogram and to validate the derived results. Forest parameters, e.g. canopy height and extinction coefficient were estimated based on Random Volume over Ground (RVoG) model. Scattering phase height (SPH) was also calculated and validated against LVIS rh100. A clear correlation was observed between TanDEM-X SPH and the reference height with an r2 of around 0.6 at 150m resolution. The inverted tree height had an RMSE of less than 3.4 m and an r2 of around 0.7 at the same resolution. It is shown that TanDEM-X data has great potential for improving the understanding and quantification of global forest canopy height and structure.

  1. ArcGeomorphometry: A toolbox for geomorphometric characterisation of DEMs in the ArcGIS environment

    NASA Astrophysics Data System (ADS)

    Rigol-Sanchez, Juan P.; Stuart, Neil; Pulido-Bosch, Antonio

    2015-12-01

    A software tool is described for the extraction of geomorphometric land surface variables and features from Digital Elevation Models (DEMs). The ArcGeomorphometry Toolbox consists of a series of Python/Numpy processing functions, presented through an easy-to-use graphical menu for the widely used ArcGIS package. Although many GIS provide some operations for analysing DEMs, the methods are often only partially implemented and can be difficult to find and used effectively. Since the results of automated characterisation of landscapes from DEMs are influenced by the extent being considered, the resolution of the source DEM and the size of the kernel (analysis window) used for processing, we have developed a tool to allow GIS users to flexibly apply several multi-scale analysis methods to parameterise and classify a DEM into discrete land surface units. Users can control the threshold values for land surface classifications. The size of the processing kernel can be used to identify land surface features across a range of landscape scales. The pattern of land surface units from each attempt at classification is displayed immediately and can then be processed in the GIS alongside additional data that can assist with a visual assessment and comparison of a series of results. The functionality of the ArcGeomorphometry toolbox is described using an example DEM.

  2. Effects of BSO and DEM on thiol-level and radiosensitivity in HeLa cells

    SciTech Connect

    Vos, O.; Van Der Schans, G.P.; Roos-Verhey, W.S.D.

    1984-08-01

    Reduction of the intracellular GSH and NPSH levels in HeLa cells by BSO and DEM treatments was determined. As parameters for radiation damage, single and double strand DNA breaks (ssb and dsb) and cell killing were used. Furthermore, repair of ssb and dsb were followed in the first 30 and 120 min after radiation, respectively. BSO and DEM treatment gave a small sensitization for the 3 types of radiation damage (ssb, dsb and cell killing) in aerobic condition. In hypoxic condition the sensitizing effect of both compounds on dsb was larger than the effect on ssb. Pretreatment with BSO and DEM had no influence on repair of ssb and dsb when cells were irradiated in air, but when cells were irradiated in hypoxia, repair was somewhat inhibited after pretreatment with DEM. It can be postulated that a reduction of the intracellular GSH level by BSO and DEM treatment affects cellular radiosensitivity both by a competitive mechanism between GSH and O/sub 2/ and by inhibition of enzymatic repair of DNA breaks, the latter only in the case of DEM treatment.

  3. Improvement of DEM quality derived by interferometric SAR by using multiple baseline data pairs

    NASA Astrophysics Data System (ADS)

    Takeuchi, S.; Oguro, Y.; Suga, Y.

    According to the study conducted by the authors on DEM generation by using InSAR with many JERS-1/SAR repeat-pass interferometric data pairs with different baseline lengths, it has been suggested that height accuracy and drawback rate are correlated to baseline better than to coherence. The drawback rate clearly decreases with smaller baseline lengths, and on the other hand, height accuracy tends to decrease with smaller baseline lengths and the range from 400 to 500 m in baseline lengths brings in the best accuracy, although the drawback rate is generally larger than that with smaller baseline length. These experimental results clearly indicate that it is basically impossible to obtain the best accuracy and drawback rate at once by a single repeat-pass data pair. One possible approach might be the use of multiple InSAR data pairs. Therefore, the authors attempt to improve the quality of DEM generated by L-band repeat-pass InSAR by using multiple InSAR data pairs with different baseline lengths. The multiple interferometric data pairs by JERS-1/SAR repeat-pass observation with different baseline lengths are used to generate DEM in several mountain test areas in Japan. After DEM generation by individual data pairs, they are merged into a final DEM product based on the regression analysis of them. The result indicates that the use of multiple baseline data pairs significantly improves DEM quality with a little increase of height error.

  4. No Substitute for Going to the Field: Correcting Lidar DEMs in Salt Marshes

    NASA Astrophysics Data System (ADS)

    Renken, K.; Morris, J. T.; Lynch, J.; Bayley, H.; Neil, A.; Rasmussen, S.; Tyrrell, M.; Tanis, M.

    2016-12-01

    Models that forecast the response of salt marshes to current and future trends in sea level rise increasingly are used to guide management of these vulnerable ecosystems. Lidar-derived DEMs serve as the foundation for modeling landform change. However, caution is advised when using these DEMs as the starting point for models of salt marsh evolution. While broad vegetation class (i.e., young forest, old forest, grasslands, desert, etc.) has proven to be a significant predictor of vertical displacement error in terrestrial environments, differentiating error among different species or community types within the same ecosystem has received less attention. Salt marshes are dominated by monocultures of grass species and thus are an ideal environment to examine the within-species effect on lidar DEM error. We analyzed error of lidar DEMs using elevations from real-time kinematic (RTK) surveys in saltmarshes in multiple national parks and wildlife refuge areas from the mouth of the Chesapeake Bay to Massachusetts. Error of the lidar DEMs was sometimes large, on the order of 0.25 m, and varied significantly between sites because vegetation cover varies seasonally and lidar data was not always collected in the same season for each park. Vegetation cover and composition were used to explain differences between RTK elevations and lidar DEMs. This research underscores the importance of collecting RTK elevation data and vegetation cover data coincident with lidar data to produce correction factors specific to individual salt marsh sites.

  5. [R]MIT Research Centre at Delft University of Technology: A Bridge between Research, Education, Society and Profession

    ERIC Educational Resources Information Center

    Zijlstra, Hielkje

    2009-01-01

    In 2006, we launched the [R]MIT Research Centre (Modification, Intervention Transformation) at the Faculty of Architecture at Delft University of Technology. [R]MIT was founded to respond to the need for an integrated, multi-disciplinary approach to the transformation of the built environment. [R]MIT aims to bring momentum to the renewal of…

  6. Coupling parameters of the MIT OBS at two nearshore sites

    NASA Astrophysics Data System (ADS)

    Tréhu, Anne M.; Solomon, Sean C.

    1981-03-01

    A model representing the coupling of an ocean-bottom seismometer (OBS) to the seafloor as a mass-spring-dashpot system satisfactorily explains the results of transient tests performed on different instruments during the Lopez Island intercomparison test. In this paper, we compare the results obtained for the MIT OBS at Lopez Island to results from similar tests at a dockside site at Woods Hole, Massachusetts. The vertical instrument response at the Lopez Island site shows a highly damped resonance at a frequency of 22 Hz, whereas the response at the Woods Hole site shows a marked resonance at 13 Hz. The difference between the responses at the two sites can be qualitatively attributed to the difference between the surficial sediments.

  7. The third MIT-Green Bank 5 GHz survey

    SciTech Connect

    Griffith, M.; Heflin, M.; Conner, S.; Lehar, J.; Langston, G. National Radio Astronomy Observatory, Charlottesville, VA )

    1990-09-01

    The third MIT-Green Bank survey, which covers 1.11 sr in the right ascension range from 16.5 h to 5 h between +17 deg and +39.15 deg declination, is presented. The survey is unique in that a sample was observed twice in a short period of time and the spectral indices between 5 and 1.4 GHz are available for most of the sources brighter than 90 mJy. This survey can be used as the starting point for a search for gravitational lenses. The source list can also be examined for clustering and used to estimate the surface density of sources as a function of limiting flux density. 10 refs.

  8. MiT family translocation renal cell carcinoma.

    PubMed

    Argani, Pedram

    2015-03-01

    The MiT subfamily of transcription factors includes TFE3, TFEB, TFC, and MiTF. Gene fusions involving two of these transcription factors have been identified in renal cell carcinoma (RCC). The Xp11 translocation RCCs were first officially recognized in the 2004 WHO renal tumor classification, and harbor gene fusions involving TFE3. The t(6;11) RCCs harbor a specific Alpha-TFEB gene fusion and were first officially recognized in the 2013 International Society of Urologic Pathology (ISUP) Vancouver classification of renal neoplasia. These two subtypes of translocation RCC have many similarities. Both were initially described in and disproportionately involve young patients, though adult translocation RCC may overall outnumber pediatric cases. Both often have unusual and distinctive morphologies; the Xp11 translocation RCCs frequently have clear cells with papillary architecture and abundant psammomatous bodies, while the t(6;11) RCCs frequently have a biphasic appearance with both large and small epithelioid cells and nodules of basement membrane material. However, the morphology of these two neoplasms can overlap, with one mimicking the other. Both of these RCCs underexpress epithelial immunohistochemical markers like cytokeratin and epithelial membrane antigen (EMA) relative to most other RCCs. Unlike other RCCs, both frequently express the cysteine protease cathepsin k and often express melanocytic markers like HMB45 and Melan A. Finally, TFE3 and TFEB have overlapping functional activity as these two transcription factors frequently heterodimerize and bind to the same targets. Therefore, on the basis of clinical, morphologic, immunohistochemical, and genetic similarities, the 2013 ISUP Vancouver classification of renal neoplasia grouped these two neoplasms together under the heading of "MiT family translocation RCC." This review summarizes our current knowledge of these recently described RCCs. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Technology and human vulnerability. A conversation with MIT's Sherry Turkle.

    PubMed

    Turkle, Sherry

    2003-09-01

    For most of the last 50 years, technology knew its place. Yes, we all spent a lot of time with it, but even five years ago, few people would seriously claim that technology had taken over their lives. It's very different today. Technology is not only ubiquitous but has become highly intrusive as well. On the Internet, people invent imaginary identities in virtual chat rooms, playing out the lives they wish they really lived. Children are growing up with interactive toy animals that respond to them like real pets. Indeed, some critics claim that technology has not just entered our private lives but started to define them. If we want to be sure we'll like who we've become in 50 years, we need to take a closer look at the psychological effects of current and future technologies. The smartest people in technology have already started. Universities like MIT and Caltech have been pouring millions of dollars into researching what happens when technology and humanity meet. To learn more about this research, HBR senior editor Diane L. Coutu spoke with one of the field's most distinguished scholars: Sherry Turkle, MIT's Abby Rockefeller Mauzé Professor in the Program in Science, Technology, and Society and the author of Life on the Screen, which explores how the internet is changing the way we define ourselves. In a conversation with Coutu, Turkle discusses the psychological dynamics that can develop between people and their high-tech toys, describes ways in which machines might substitute for managers, and explains how technology is redefining what it means to be human. She warns that relatively small differences in technology design can have disproportionate effects on how humans relate to technology, to one another, and to themselves.

  10. Shape and Albedo from Shading (SAfS) for Pixel-Level dem Generation from Monocular Images Constrained by Low-Resolution dem

    NASA Astrophysics Data System (ADS)

    Wu, Bo; Chung Liu, Wai; Grumpe, Arne; Wöhler, Christian

    2016-06-01

    Lunar topographic information, e.g., lunar DEM (Digital Elevation Model), is very important for lunar exploration missions and scientific research. Lunar DEMs are typically generated from photogrammetric image processing or laser altimetry, of which photogrammetric methods require multiple stereo images of an area. DEMs generated from these methods are usually achieved by various interpolation techniques, leading to interpolation artifacts in the resulting DEM. On the other hand, photometric shape reconstruction, e.g., SfS (Shape from Shading), extensively studied in the field of Computer Vision has been introduced to pixel-level resolution DEM refinement. SfS methods have the ability to reconstruct pixel-wise terrain details that explain a given image of the terrain. If the terrain and its corresponding pixel-wise albedo were to be estimated simultaneously, this is a SAfS (Shape and Albedo from Shading) problem and it will be under-determined without additional information. Previous works show strong statistical regularities in albedo of natural objects, and this is even more logically valid in the case of lunar surface due to its lower surface albedo complexity than the Earth. In this paper we suggest a method that refines a lower-resolution DEM to pixel-level resolution given a monocular image of the coverage with known light source, at the same time we also estimate the corresponding pixel-wise albedo map. We regulate the behaviour of albedo and shape such that the optimized terrain and albedo are the likely solutions that explain the corresponding image. The parameters in the approach are optimized through a kernel-based relaxation framework to gain computational advantages. In this research we experimentally employ the Lunar-Lambertian model for reflectance modelling; the framework of the algorithm is expected to be independent of a specific reflectance model. Experiments are carried out using the monocular images from Lunar Reconnaissance Orbiter (LRO

  11. Uncertainty Assessment and Weight Map Generation for Efficient Fusion of Tandem-X and CARTOSAT-1 Dems

    NASA Astrophysics Data System (ADS)

    Bagheri, H.; Schmitt, M.; Zhu, X. X.

    2017-05-01

    Recently, with InSAR data provided by the German TanDEM-X mission, a new global, high-resolution Digital Elevation Model (DEM) has been produced by the German Aerospace Center (DLR) with unprecedented height accuracy. However, due to SAR-inherent sensor specifics, its quality decreases over urban areas, making additional improvement necessary. On the other hand, DEMs derived from optical remote sensing imagery, such as Cartosat-1 data, have an apparently greater resolution in urban areas, making their fusion with TanDEM-X elevation data a promising perspective. The objective of this paper is two-fold: First, the height accuracies of TanDEM-X and Cartosat-1 elevation data over different land types are empirically evaluated in order to analyze the potential of TanDEM-XCartosat- 1 DEM data fusion. After the quality assessment, urban DEM fusion using weighted averaging is investigated. In this experiment, both weight maps derived from the height error maps delivered with the DEM data, as well as more sophisticated weight maps predicted by a procedure based on artificial neural networks (ANNs) are compared. The ANN framework employs several features that can describe the height residual performance to predict the weights used in the subsequent fusion step. The results demonstrate that especially the ANN-based framework is able to improve the quality of the final DEM through data fusion.

  12. Bathymetric survey of water reservoirs in north-eastern Brazil based on TanDEM-X satellite data.

    PubMed

    Zhang, Shuping; Foerster, Saskia; Medeiros, Pedro; de Araújo, José Carlos; Motagh, Mahdi; Waske, Bjoern

    2016-11-15

    Water scarcity in the dry season is a vital problem in dryland regions such as northeastern Brazil. Water supplies in these areas often come from numerous reservoirs of various sizes. However, inventory data for these reservoirs is often limited due to the expense and time required for their acquisition via field surveys, particularly in remote areas. Remote sensing techniques provide a valuable alternative to conventional reservoir bathymetric surveys for water resource management. In this study single pass TanDEM-X data acquired in bistatic mode were used to generate digital elevation models (DEMs) in the Madalena catchment, northeastern Brazil. Validation with differential global positioning system (DGPS) data from field measurements indicated an absolute elevation accuracy of approximately 1m for the TanDEM-X derived DEMs (TDX DEMs). The DEMs derived from TanDEM-X data acquired at low water levels show significant advantages over bathymetric maps derived from field survey, particularly with regard to coverage, evenly distributed measurements and replication of reservoir shape. Furthermore, by mapping the dry reservoir bottoms with TanDEM-X data, TDX DEMs are free of emergent and submerged macrophytes, independent of water depth (e.g. >10m), water quality and even weather conditions. Thus, the method is superior to other existing bathymetric mapping approaches, particularly for inland water bodies. The proposed approach relies on (nearly) dry reservoir conditions at times of image acquisition and is thus restricted to areas that show considerable water levels variations. However, comparisons between TDX DEM and the bathymetric map derived from field surveys show that the amount of water retained during the dry phase has only marginal impact on the total water volume derivation from TDX DEM. Overall, DEMs generated from bistatic TanDEM-X data acquired in low water periods constitute a useful and efficient data source for deriving reservoir bathymetry and show

  13. Recent Release of the ASTER Global DEM Product

    NASA Astrophysics Data System (ADS)

    Behnke, J.; Hall, A.; Meyer, D.; Sohre, T.; Doescher, C.

    2009-12-01

    On June 29th, the ASTER Global Digital Elevation Model (DEM) release was announced to the public and to a very eager audience. ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) is an imaging instrument flying on Terra, a satellite launched in December 1999 as part of NASA's Earth Observing System (EOS). ASTER is a cooperative effort between NASA, Japan's Ministry of Economy, Trade and Industry (METI) and Japan's Earth Remote Sensing Data Analysis Center (ERSDAC). On June 21, NASA Headquarters along with colleagues in Japan (METI) signed a plan for distribution of this product. The global digital elevation model of Earth is available online to users everywhere at no cost from NASA's Land Processes Distributed Active Archive Center (DAAC) located at Sioux Falls, SD. The DAAC is a joint project of NASA and the USGS and is a key component of NASA's EOSDIS. The new ASTER GDEM was created from nearly 1.3 million individual stereo-pair images acquired by the Japanese Advanced Spaceborne Thermal Emission and Reflection Radiometer (Aster) instrument aboard NASA’s Terra satellite. The ASTER elevation model was jointly developed by NASA and METI under contract to Sensor Information Laboratory Corp., Tsukuba, Japan. On June 29, the NASA press release was picked up quickly by numerous news organizations and online sites. Response to the product was incredible! The news of the release of the product was carried on websites across the globe, this fueled a tremendous response from users. Here are a few interesting metrics about the release: - over 41,000 unique visitors to website in first week following release - top countries in order were: US (approx. 20%), Germany, U.K., Brazil, Austria, Canada, Spain, Switzerland, Japan - approximately 29,000 visitors came to the news page in the first week and about 11,000 of these users downloaded the actual press release - by the end of August, over 2 Million ASTER GDEM files had been downloaded from the Land

  14. Perspective - synthetic DEMs: A vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Sofia, G.; Conway, S. J.

    2015-12-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g. Earth's). A fundamental tenet of geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Artificial or synthetic digital elevation models (DEMs) might be vital in progressing further with this endeavour in two ways. First, synthetic DEMs can be built (e.g. by directly using governing equations) to encapsulate the processes, making predictions from theory. A second, arguably underutilised, role is to perform checks on accuracy and robustness that we dub "synthetic tests". Specifically, synthetic DEMs can contain a priori known, idealised morphologies that numerical landscape evolution models, DEM-analysis algorithms, and even manual mapping can be assessed against. Some such tests, for instance examining inaccuracies caused by noise, are moderately commonly employed, whilst others are much less so. Derived morphological properties, including metrics and mapping (manual and automated), are required to establish whether or not conceptual models represent reality well, but at present their quality is typically weakly constrained (e.g. by mapper inter-comparison). Relatively rare examples illustrate how synthetic tests can make strong "absolute" statements about landform detection and quantification; for example, 84 % of valley heads in the real landscape are identified correctly. From our perspective, it is vital to verify such statistics quantifying the properties of landscapes as ultimately this is the link between physics-driven models of processes and morphological observations that allows quantitative hypotheses to be tested. As such the additional rigour possible with this second usage of synthetic DEMs feeds directly into a problem central to the validity of much of geomorphology. Thus, this note introduces synthetic tests and DEMs and then outlines a typology of synthetic DEMs along with their benefits

  15. CFD-DEM simulations of current-induced dune formation and morphological evolution

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Xiao, Heng

    2016-06-01

    Understanding the fundamental mechanisms of sediment transport, particularly those during the formation and evolution of bedforms, is of critical scientific importance and has engineering relevance. Traditional approaches of sediment transport simulations heavily rely on empirical models, which are not able to capture the physics-rich, regime-dependent behaviors of the process. With the increase of available computational resources in the past decade, CFD-DEM (computational fluid dynamics-discrete element method) has emerged as a viable high-fidelity method for the study of sediment transport. However, a comprehensive, quantitative study of the generation and migration of different sediment bed patterns using CFD-DEM is still lacking. In this work, current-induced sediment transport problems in a wide range of regimes are simulated, including 'flat bed in motion', 'small dune', 'vortex dune' and suspended transport. Simulations are performed by using SediFoam, an open-source, massively parallel CFD-DEM solver developed by the authors. This is a general-purpose solver for particle-laden flows tailed for particle transport problems. Validation tests are performed to demonstrate the capability of CFD-DEM in the full range of sediment transport regimes. Comparison of simulation results with experimental and numerical benchmark data demonstrates the merits of CFD-DEM approach. In addition, the improvements of the present simulations over existing studies using CFD-DEM are presented. The present solver gives more accurate prediction of sediment transport rate by properly accounting for the influence of particle volume fraction on the fluid flow. In summary, this work demonstrates that CFD-DEM is a promising particle-resolving approach for probing the physics of current-induced sediment transport.

  16. Visualization and comparison of DEM-derived parameters. Application to volcanic areas

    NASA Astrophysics Data System (ADS)

    Favalli, Massimiliano; Fornaciai, Alessandro

    2017-08-01

    Digital Elevation Models (DEMs) are fruitfully used in volcanology as the topographic base for mapping and quantifying volcanic landforms. The increasing availability of free topographic data on the web, decreasing production costs for high-accuracy data and advances in computer technology, has triggered rapid growth of the number of DEM users in the volcanological community. DEMs are often visualized only as hill-shaded maps, and while this is among the major advantages in using them, the possibility of deriving a very large number of parameters from a single grid of elevation data makes DEMs a powerful tool for morphometric analysis. However, many of these parameters have almost the same informative content, and before starting to elaborate topographic data it is recommended to know a-priori what parameters best visualize the investigated landform, and therefore what is necessary and what is redundant. In this work, we review a number of analytical procedures used to parameterize and represent DEMs. A LIDAR-derived DEM matrix acquired over the Valle del Bove valley, on Mt. Etna, is used as test-case elevation data for deriving the parameters. We first review well known parameters such as hill-shading, slope and aspect, curvature, and roughness, before extending the review to some less common parameters such as Sky View Factor (SVF), openness, and Red Relief Image Maps (RRIM). For each parameter a description is given emphasizing how it can be used for identifying and delimiting specific volcanic elements. The analyzed surface parameters are then cross-compared in order to infer which of them is most uncorrelated, and the results are represented in the form of a correlation matrix. Finally, the reviewed DEM-derived parameters and the correlation matrix are used for analyzing the volcanic landforms of two case studies: Michoacán-Guanajuato volcanic field and a phonolitic lava flow at the Island of Tenerife.

  17. Effects of LiDAR Derived DEM Resolution on Hydrographic Feature Extraction

    NASA Astrophysics Data System (ADS)

    Yang, P.; Ames, D. P.; Glenn, N. F.; Anderson, D.

    2010-12-01

    This paper examines the effect of LiDAR-derived digital elevation model (DEM) resolution on digitally extracted stream networks with respect to known stream channel locations. Two study sites, Reynolds Creek Experimental Watershed (RCEW) and Dry Creek Experimental Watershed (DCEW), which represent terrain characteristics for lower and intermediate elevation mountainous watersheds in the Intermountain West, were selected as study areas for this research. DEMs reflecting bare earth ground were created from the LiDAR observations at a series of raster cell sizes (from 1 m to 60 m) using spatial interpolation techniques. The effect of DEM resolution on resulting hydrographic feature (specifically stream channel) derivation was studied. Stream length, watershed area, and sinuosity were explored at each of the raster cell sizes. Also, variation from known channel location as estimated by root mean square error (RMSE) between surveyed channel location and extracted channel was computed for each of the DEMs and extracted stream networks. As expected, the results indicate that the DEM based hydrographic extraction process provides more detailed hydrographic features at a finer resolution. RMSE between the known channel location and modeled locations generally increased with larger cell size DEM with a greater effect in the larger RCEW. Sensitivity analyses on sinuosity demonstrated that the resulting shape of streams obtained from LiDAR data matched best with the reference data at an intermediate cell size instead of highest resolution, which is at a range of cell size from 5 to 10 m likely due to original point spacing, terrain characteristics, and LiDAR noise influence. More importantly, the absolute sinuosity deviation displayed a smallest value at the cell size of 10 m in both experimental watersheds, which suggests that optimal cell size for LiDAR-derived DEMs used for hydrographic feature extraction is 10 m.

  18. Evaluation of the MIT RMID 1000 system for the identification of Listeria species.

    PubMed

    Ricardi, John; Haavig, David; Cruz, Lasaunta; Paoli, George; Gehring, Andrew

    2010-01-01

    The Micro Imaging Technology (MIT) 1000 Rapid Microbial Identification (RMID) System is a device that uses the principles of light scattering coupled with proprietary algorithms to identify bacteria after being cultured and placed in a vial of filtered water. This specific method is for pure culture identification of Listeria spp. A total of 81 microorganisms (55 isolates) were tested by the MIT 1000 System, of which 25 were Listeria spp. and 30 a variety of other bacterial species. In addition, a total of 406 tests over seven different ruggedness parameters were tested by the MIT 1000 System to determine its flexibility to the specifications stated in the MIT 1000 System User Guide in areas where they might be deviated by a user to shorten the test cycle. Overall, MIT concluded that the MIT 1000 System had an accuracy performance that should certify this Performance Test Method for the identification of Listeria spp. This report discusses the tests performed, results achieved, and conclusions, along with several reference documents to enable a higher understanding of the technology used by the MIT 1000 System.

  19. Gebrauch von Komplementärmedizin bei Patienten mit metastasierendem Melanom unter Therapie mit Ipilimumab innerhalb einer klinischen Studie.

    PubMed

    Huebner, Jutta; Mohr, Peter; Simon, Jan-Christoph; Fluck, Michael; Berking, Carola; Zimmer, Lisa; Loquai, Carmen

    2016-05-01

    In Deutschland wenden 40-90 % aller Krebspatienten Methoden der komplementären and alternativen Medizin (KAM) an. Bis dato gibt es kein Datenmaterial zum Einsatz der KAM bei Melanompatienten. Das Ziel unserer Studie war es, Daten über den Gebrauch, die Informationsquellen und Ziele von Patienten mit metastasierendem Melanom zu erfassen. Einhundertsechsundfünfzig Patienten aus 25 Studienzentren nahmen an der DecOG-MM-PAL Multibasket Studie teil. Die beteiligten Personen wurden auch gebeten, an einer Nebenstudie teilzunehmen, die ihren Gebrauch von KAM erfassen sollte. Dazu wurde während der Behandlung ein standardisierter Fragebogen zu genau festgelegten Zeitpunkten ausgeteilt. Insgesamt gingen 55 Fragebögen von 32 (21 %) Melanompatienten ein. Von diesen gaben 17 (53 %) ein Interesse an KAM an, und sieben (22 %) machten von KAM Gebrauch. Die Hauptinformationsquellen (31 %) waren Familienmitglieder und Freunde, gefolgt von Ärzten (19 %). Die Hauptgründe für die Anwendung von KAM waren die Stärkung des Immunsystems (41 %) und des Körpers (34 %). Nahrungsergänzungsmittel (Vitamine und Spurenelemente) wurden am häufigsten angewendet (28 %). Eine relativ hohe Anzahl an Patienten mit metastasierendem Melanom machte trotz Teilnahme an einer klinischen Studie von KAM Gebrauch. Wechselwirkungen könnten durch biologisch basierte KAM auftreten, und hier besonders bei immunmodulierenden KAM- Strategien. Um Risiken zu vermeiden, sollte die Kommunikation zwischen den Ärzten und den Patienten verbessert werden. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  20. Having Fun with Physics at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Thomas, P.; Censabella, V.; Granville, J.; Nachtrieb, R.; Gangadhara, S.

    1997-11-01

    MIT Plasma Science and Fusion Center staff and students are convinced that students learn best not by studying but by doing. This was the impetus behind a group of MIT graduate students who created Cambridge Physics Outlet, a PSFC spin-off company dedicated to creating hands-on experiments. The same impulse fostered the award-winning Mr. Magnet Program, a traveling presentation which uses a hands-on strategy to engage elementary school children. A number of ingenious experiments will be demonstrated. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

  1. Segmentierung des Femurs aus MRT-Daten mit Shape-Based Level-Sets

    NASA Astrophysics Data System (ADS)

    Dekomien, Claudia; Busch, Martin; Teske, Wolfram; Winter, Susanne

    Inhalt dieser Arbeit ist die Segmentierung des Femurs aus MRT-Datensätzen mit einem Shape-based Level-Set-Ansatz. Der Algorithmus besteht aus zwei Phasen, der Modellerstellung und der Segmentierungsphase. In der Segmentierungsphase wurde ein kantenbasiertes und ein auf Intensitäten basierendes Optimierungskriterium mit einander kombiniert. Für eine lokale Verbesserung des Ergebnisses wurde zusätzlich ein Laplacian Level-Set-Verfahren angewendet. Der Femur konnte mit diesem Ansatz in drei verschiedenen MRT-Sequenzen und einem Fusionsdatensatz gut segmentiert werden.

  2. Utility of the M.I.T. (Massachusetts Institute of Technology) Underwater Stud Welding Gun.

    DTIC Science & Technology

    1984-06-01

    MASSACHUSETTS INSTITUTE OF TECHNOLOGY CAMBRIDGE, MASSACHUSETTS 02139 UTILITY OF THE MIT U-A.RWATER STUD WELDING ; GUN ~{VRY ~iPR>UfIT, JR. JLieuLk2fillL U...zv ~ :(X.~ML)Course 1 3A N ’T unle 1984 .................... A.r " 1- My Ms 31cmmWffi.ZL UTILITY OF THE M.I.T. UNDERWATER STUD WELDING GUN by...A Accession For NTIS GRA&I e.. DTIC TAB UTILITY OF THE M.I.T. Dist" " UNDERWATER STUD WELDING GUN Dist I - "-by I !- Henry Lowe Pruitt, Jr

  3. Star in Deep Freeze Chills Theory, MIT Researchers Report

    NASA Astrophysics Data System (ADS)

    2001-09-01

    CAMBRIDGE, Mass. -- Like a frozen turkey that just won't thaw, a strange star near the center of the Milky Way is surprising MIT experts and colleagues with its remarkably low temperature. The odd behavior is chilling current theories of stellar physics. A famously battered neutron star named KS 1731-260 appears no hotter than some of its tranquil brethren, despite enduring the heat of constant thermonuclear explosions with the force of billions of hydrogen bombs every second across a region only a few miles wide for the past 12 years. Dr. Rudi Wijnands, an astrophysicist at MIT's Center for Space Research, used the Chandra X-ray Observatory to measure the temperature of the neutron star at a very opportune moment, only months after the nuclear war apparently ended and the smoke cleared. He presented his team's findings September 5 in Washington, D.C. at a scientific conference entitled "Two Years of Science with Chandra." "Twelve years of constant thermonuclear explosions: One would think that would heat things up," said Wijnands. "This leaves us wondering whether some neutron stars are in the freezer for a much longer time than previously thought and consequently take a long time to heat up, or whether they cool down incredibly fast. Either explanation has profound implications for our field." Neutron stars are the dense, core remains of stars once many times more massive than our Sun. They are created in dazzling supernovas, in which the outer shell of the star explodes into space, and the core, containing about as much mass as the Sun, implodes and collapses into a sphere no wider than Cambridge, Massachusetts. Despite their tiny size, neutron stars are visible in several ways. One is through accretion. Neutron stars are a strong source of gravity. When they exist in binary star systems, such as KS 1731-260, they can attract the gas from what is often a "healthy" hydrogen-burning companion star (although the nature of KS 1731-260's companion is not clear.) Gas

  4. Acute environmental toxicity and persistence of DEM, a chemical agent simulant: Diethyl malonate. [Diethyl malonate

    SciTech Connect

    Cataldo, D.A.; Ligotke, M.W.; Harvey, S.D.; Fellows, R.J.; Li, Shu-mei W.; Van Voris, P.; Wentsel, R.S.

    1990-05-01

    The purpose of the following chemical simulant studies is to assess the potential acute environmental effects and persistence of diethyl malonate (DEM). Deposition velocities for DEM to soil surfaces ranged from 0.04 to 0.2 cm/sec. For foliar surfaces, deposition velocities ranged from 0.0002 cm/sec at low air concentrations to 0.05 cm/sec for high dose levels. The residence times or half-lives of DEM deposited to soils was 2 h for the fast component and 5 to 16 h for the residual material. DEM deposited to foliar surfaces also exhibited biphasic depuration. The half-life of the short residence time component ranged from 1 to 3 h, while the longer time component had half-times of 16 to 242 h. Volatilization and other depuration mechanisms reduce surface contaminant levels in both soils and foliage to less than 1% of initial dose within 96 h. DEM is not phytotoxic at foliar mass loading levels of less than 10 {mu}m/cm{sup 2}. However, severe damage is evident at mass loading levels in excess of 17 {mu}g/cm{sup 2}. Tall fescue and sagebrush were more affected than was short-needle pine, however, mass loading levels were markedly different. Regrowth of tall fescue indicated that the effects of DEM are residual, and growth rates are affected only at higher mass loadings through the second harvest. Results from in vitro testing of DEM indicated concentrations below 500 {mu}g/g dry soil generally did not negatively impact soil microbial activity. Short-term effects of DEM were more profound on soil dehydrogenase activity than on soil phosphatase activity. No enzyme inhibition or enhancement was observed after 28 days in incubation. Results of the earthworm bioassay indicate survival to be 86 and 66% at soil doses of 107 and 204 {mu}g DEM/cm{sup 2}, respectively. At higher dose level, activity or mobility was judged to be affected in over 50% of the individuals. 21 refs., 10 figs., 15 tabs.

  5. Melker Meilensteine auf dem Weg in ein naturwissenschaftliches Zeitalter - Glanzlichter der Ausstellung zum Internationalen Astronomiejahr 2009 in der Melker Stiftsbibliothek.

    NASA Astrophysics Data System (ADS)

    Beck, Paul G.; Zotti, Georg

    2009-06-01

    Das Mittelalter wird weithin als die dunkle Epoche in der Geschichte der Europäischen Wissenschaften betrachtet, und insbesondere das Leben in den Klöstern galt lange Zeit als frei von jeglichem Interesse für Naturwissenschaften abseits der Medizin. Im Mittelalter galt die Astronomie bloß als Mittel zum Zweck, um religiöse und zivile Kalender erstellen zu können. Durch den Bestand der Handschriftenkammer der Melker Stiftsbibliothek eröffnet sich uns eine neue Sichtweise auf das gegen Ende des Mittelalters wachsende Interesse an den Naturwissenschaften. Dies wurde durch die starke Aufwertung der Klosterbibliothek im Rahmen der 'Melker Reform' im 15. Jahrhundert noch weiter verstärkt. Diese Epoche fällt mit der Frühphase der Universität Wien und der 'ersten Wiener Schule der Astronomie' zusammen. Dieser Artikel beleuchtet ausgewählte astronomischen Werke in der Melker Stiftsbibliothek zwischen dem frühen 9 und dem 18. Jahrhundert. Einen Schwerpunkt stellt das Wirken der Wiener Schule der Astronomie dar, wobei wir u.a. die Melker Abschrift von Peuerbachs Gutachten über den Kometen von 1456 sowie die im Stift Melk durchgeführte Beobachtung der Mondfinsternis von 1457 durch Regiomontanus und Peuerbach beleuchten. Dieser Beitrag ist der einführende Übersichtsartikel zum Ausstellungsprojekt in der Melker Stiftsbibliothek im Rahmen des Internationalen Jahres der Astronomie 2009. The medieval period is commonly seen as a dark epoch for science in Europe. Especially monasteries were seen as institutions without interest in natural sciences except for medicine. Astronomy was allegedly only a tool to construct religious and civil calendars. The inventory of the medieval manuscript collection of the library of the Abbey of Melk allows a new view on the growing interest in the exact sciences towards the end of the medieval ages. This interest was intensified through the increased importance of the monastery library due to the monastery reform

  6. Perspective - synthetic DEMs: a vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Sofia, G.; Conway, S. J.

    2015-07-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g., Earth's). A fundamental tenet of Geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Artificial or synthetic Digital Elevation Models (DEMs) might be vital in progressing further with this endeavour. Morphological data, including metrics and mapping (manual and automated) are a key resource, but at present their quality is typically weakly constrained (e.g., by mapper inter-comparison). In addition to examining inaccuracies caused by noise, relatively rare examples illustrate how synthetic DEMs containing a priori known, idealised morphologies can be used perform "synthetic tests" to make strong "absolute" statements about landform detection and quantification; e.g., 84 % of valley heads in the real landscape are identified correctly. From our perspective, it is vital to verify such statistics as ultimately they link physics-driven models of processes to morphological observations, allowing quantitative hypotheses to be formulated and tested. Synthetic DEMs built by directly using governing equations that encapsulate processes are another key part of forming this link. Thus, this note introduces synthetic tests and DEMs, then it outlines a typology of synthetic DEMs along with their benefits, challenges and future potential to provide constraints and insights. The aim is to discuss how we best proceed with uncertainty-aware landscape analysis to examine physical processes.

  7. The Slowly Varying Corona: Findings using DEMs from the EVE MEGS-A Dataset

    NASA Astrophysics Data System (ADS)

    Schonfeld, Samuel J.; White, Stephen M.; Hock, Rachel A.; Henney, Carl John; McAteer, James

    2017-08-01

    We present analysis of the complete spectral dataset from the Extreme-ultraviolet (EUV) Variability Experiment (EVE) MEGS-A instrument. With these data we construct daily differential emission measures (DEMs) and use them to analyze the long-term variability of the global corona. We identify a discontinuity in the DEMs separating solar minimum and maximum conditions that suggests a fundamental change in the coronal temperature structure with solar activity. Using the DEMs, we also study the relationship between EUV and F10.7, the 10.7 cm (2.8 GHz) solar activity proxy. We compare the F10.7 predictions from the DEMs and photospheric magnetic field observations with irradiance microwave observations to constrain the source mechanisms of F10.7 and their relative contribution as a function of solar activity. This has serious implications for the use of F10.7 as an activity proxy in terrestrial atmospheric modeling and we discuss our results in the context of previous work. Comparing the DEMs with microwave observations also allows for a determination of the coronal iron abundance and a measurement of the FIP effect.

  8. An advanced distributed automated extraction of drainage network model on high-resolution DEM

    NASA Astrophysics Data System (ADS)

    Mao, Y.; Ye, A.; Xu, J.; Ma, F.; Deng, X.; Miao, C.; Gong, W.; Di, Z.

    2014-07-01

    A high-resolution and high-accuracy drainage network map is a prerequisite for simulating the water cycle in land surface hydrological models. The objective of this study was to develop a new automated extraction of drainage network model, which can get high-precision continuous drainage network on high-resolution DEM (Digital Elevation Model). The high-resolution DEM need too much computer resources to extract drainage network. The conventional GIS method often can not complete to calculate on high-resolution DEM of big basins, because the number of grids is too large. In order to decrease the computation time, an advanced distributed automated extraction of drainage network model (Adam) was proposed in the study. The Adam model has two features: (1) searching upward from outlet of basin instead of sink filling, (2) dividing sub-basins on low-resolution DEM, and then extracting drainage network on sub-basins of high-resolution DEM. The case study used elevation data of the Shuttle Radar Topography Mission (SRTM) at 3 arc-second resolution in Zhujiang River basin, China. The results show Adam model can dramatically reduce the computation time. The extracting drainage network was continuous and more accurate than HydroSHEDS (Hydrological data and maps based on Shuttle Elevation Derivatives at multiple Scales).

  9. Optimizing grid computing configuration and scheduling for geospatial analysis: An example with interpolating DEM

    NASA Astrophysics Data System (ADS)

    Huang, Qunying; Yang, Chaowei

    2011-02-01

    Many geographic analyses are very time-consuming and do not scale well when large datasets are involved. For example, the interpolation of DEMs (digital evaluation model) for large geographic areas could become a problem in practical application, especially for web applications such as terrain visualization, where a fast response is required and computational demands exceed the capacity of a traditional single processing unit conducting serial processing. Therefore, high performance and parallel computing approaches, such as grid computing, were investigated to speed up the geographic analysis algorithms, such as DEM interpolation. The key for grid computing is to configure an optimized grid computing platform for the geospatial analysis and optimally schedule the geospatial tasks within a grid platform. However, there is no research focused on this. Using DEM interoperation as an example, we report our systematic research on configuring and scheduling a high performance grid computing platform to improve the performance of geographic analyses through a systematic study on how the number of cores, processors, grid nodes, different network connections and concurrent request impact the speedup of geospatial analyses. Condor, a grid middleware, is used to schedule the DEM interpolation tasks for different grid configurations. A Kansas raster-based DEM is used for a case study and an inverse distance weighting (IDW) algorithm is used in interpolation experiments.

  10. TecDEM: A MATLAB Based Toolbox for understanding Tectonics from Digital Elevation Models

    NASA Astrophysics Data System (ADS)

    Shahzad, F.; Mahmood, S. A.; Gloaguen, R.

    2009-04-01

    TecDEM is a MATLAB based tool box for understanding the tectonics from digital elevation models (DEMs) of any area. These DEMs can be derived from data of any spatial resolution (Low, medium and High). In the first step we extract drainage network from the DEMs using flow grid approach. Drainage network is a group of streams having elevation and catchment area information as a function of spatial locations. We implement an array of stream structure to study this drainage network. Knickpoints can be identified on each stream of the drainage network by a graphical user interface and are helpful for understanding stream morphology. Stream profile analysis in steady state condition is applied on all streams to calculate geomorphic parameters and regional uplift rates. Hack index is calculated for all the profiles at a certain interval and over the change of knickpoints. Reports menu of this tool box generates detailed statistics report, complete tabulated report, graphical output of each analyzed stream profile and Hack index profile. All the calculated values are part of stream structure and is saved as .mat file for later use with this tool box. The spatial distribution of geomorphic parameters, uplift rates and knickpoints are exported as a shape files for visualization in professional GIS software. We test this tool box on DEMs from different tectonic settings worldwide and received verifiable results with other studies.

  11. Fusion of Multi-Scale Dems from Descent and Navcm Images of CHANG'E-3 Using Compressed Sensing Method

    NASA Astrophysics Data System (ADS)

    Peng, M.; Wan, W.; Liu, Z.; Di, K.

    2017-07-01

    The multi-source DEMs generated using the images acquired in the descent and landing phase and after landing contain supplementary information, and this makes it possible and beneficial to produce a higher-quality DEM through fusing the multi-scale DEMs. The proposed fusion method consists of three steps. First, source DEMs are split into small DEM patches, then the DEM patches are classified into a few groups by local density peaks clustering. Next, the grouped DEM patches are used for sub-dictionary learning by stochastic coordinate coding. The trained sub-dictionaries are combined into a dictionary for sparse representation. Finally, the simultaneous orthogonal matching pursuit (SOMP) algorithm is used to achieve sparse representation. We use the real DEMs generated from Chang'e-3 descent images and navigation camera (Navcam) stereo images to validate the proposed method. Through the experiments, we have reconstructed a seamless DEM with the highest resolution and the largest spatial coverage among the input data. The experimental results demonstrated the feasibility of the proposed method.

  12. Validation of digital elevation models (DEMs) and comparison of geomorphic metrics on the southern Central Andean Plateau

    NASA Astrophysics Data System (ADS)

    Purinton, Benjamin; Bookhagen, Bodo

    2017-04-01

    In this study, we validate and compare elevation accuracy and geomorphic metrics of satellite-derived digital elevation models (DEMs) on the southern Central Andean Plateau. The plateau has an average elevation of 3.7 km and is characterized by diverse topography and relief, lack of vegetation, and clear skies that create ideal conditions for remote sensing. At 30 m resolution, SRTM-C, ASTER GDEM2, stacked ASTER L1A stereopair DEM, ALOS World 3D, and TanDEM-X have been analyzed. The higher-resolution datasets include 12 m TanDEM-X, 10 m single-CoSSC TerraSAR-X/TanDEM-X DEMs, and 5 m ALOS World 3D. These DEMs are state of the art for optical (ASTER and ALOS) and radar (SRTM-C and TanDEM-X) spaceborne sensors. We assessed vertical accuracy by comparing standard deviations of the DEM elevation versus 307 509 differential GPS measurements across 4000 m of elevation. For the 30 m DEMs, the ASTER datasets had the highest vertical standard deviation at > 6.5 m, whereas the SRTM-C, ALOS World 3D, and TanDEM-X were all < 3.5 m. Higher-resolution DEMs generally had lower uncertainty, with both the 12 m TanDEM-X and 5 m ALOS World 3D having < 2 m vertical standard deviation. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the low uncertainty across these attributes for SRTM-C (30 m), TanDEM-X (12-30 m), and ALOS World 3D (5-30 m). Single-CoSSC TerraSAR-X/TanDEM-X 10 m DEMs and the 30 m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and ASTER Stack). Based on low vertical standard deviations and visual inspection alongside optical satellite data, we selected the 30 m SRTM-C, 12-30 m TanDEM-X, 10 m single-CoSSC TerraSAR-X/TanDEM-X, and 5 m ALOS World 3D for geomorphic metric comparison in a 66 km2 catchment with a distinct river knickpoint. Consistent m/n values were found using chi plot channel profile analysis, regardless of DEM type and spatial resolution. Slope, curvature

  13. Solution of the inverse problem of magnetic induction tomography (MIT).

    PubMed

    Merwa, Robert; Hollaus, Karl; Brunner, Patricia; Scharfetter, Hermann

    2005-04-01

    Magnetic induction tomography (MIT) of biological tissue is used to reconstruct the changes in the complex conductivity distribution inside an object under investigation. The measurement principle is based on determining the perturbation DeltaB of a primary alternating magnetic field B0, which is coupled from an array of excitation coils to the object under investigation. The corresponding voltages DeltaV and V0 induced in a receiver coil carry the information about the passive electrical properties (i.e. conductivity, permittivity and permeability). The reconstruction of the conductivity distribution requires the solution of a 3D inverse eddy current problem. As in EIT the inverse problem is ill-posed and on this account some regularization scheme has to be applied. We developed an inverse solver based on the Gauss-Newton-one-step method for differential imaging, and we implemented and tested four different regularization schemes: the first and second approaches employ a classical smoothness criterion using the unit matrix and a differential matrix of first order as the regularization matrix. The third method is based on variance uniformization, and the fourth method is based on the truncated singular value decomposition. Reconstructions were carried out with synthetic measurement data generated with a spherical perturbation at different locations within a conducting cylinder. Data were generated on a different mesh and 1% random noise was added. The model contained 16 excitation coils and 32 receiver coils which could be combined pairwise to give 16 planar gradiometers. With 32 receiver coils all regularization methods yield fairly good 3D-images of the modelled changes of the conductivity distribution, and prove the feasibility of difference imaging with MIT. The reconstructed perturbations appear at the right location, and their size is in the expected range. With 16 planar gradiometers an additional spurious feature appears mirrored with respect to the median

  14. Blaze-DEMGPU: Modular high performance DEM framework for the GPU architecture

    NASA Astrophysics Data System (ADS)

    Govender, Nicolin; Wilke, Daniel N.; Kok, Schalk

    Blaze-DEMGPU is a modular GPU based discrete element method (DEM) framework that supports polyhedral shaped particles. The high level performance is attributed to the light weight and Single Instruction Multiple Data (SIMD) that the GPU architecture offers. Blaze-DEMGPU offers suitable algorithms to conduct DEM simulations on the GPU and these algorithms can be extended and modified. Since a large number of scientific simulations are particle based, many of the algorithms and strategies for GPU implementation present in Blaze-DEMGPU can be applied to other fields. Blaze-DEMGPU will make it easier for new researchers to use high performance GPU computing as well as stimulate wider GPU research efforts by the DEM community.

  15. Combining DEM parameters with Landsat MSS and TM imagery in a GIS for mountain glacier characterization

    NASA Astrophysics Data System (ADS)

    Gratton, Denis J.; Howarth, Philip J.; Marceau, Danielle J.

    1990-07-01

    The building of a glaciological database is explored as an answer to the management of multisource and multiscale information required for the study of mountain glacier variations. Topographic information is derived from the 1:250,000 scale digital elevation model (DEM) of the Surveys and Mapping Branch of Energy, Mines and Resources, Canada. The interfacing of a geographic information system (GIS) and an image-analysis system (IAS) permits the inclusion of ancillary glaciological information in the automated sampling of training and test data for multispectral classification of Landsat MSS and TM imagery. The combination of visually and automatically classified covers increases the classification accuracy of MSS and TM data by 24 percent and 13 percent, respectively. Slope and aspect coverages are extracted from the raster DEM. The integration of satellite image classifications and DEM features in SPANS permits the subdivision of glacier basin covers into physiographic units. An example is presented for the ablation zone covers of the Columbia Icefield.

  16. A Detailed Observation of a LMC SNR, DEM L241, with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bamba, Aya; Ueno, Masaru; Nakajima, Hiroshi; Mori, Koji; Koyama, Katsuji

    We report on an XMM-Newton observation of the supernova remnant (SNR) DEM L241 in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish (Head and Tail), with a central point source, named as XMMU J053559.3-673509 (Eye). The Eye's spectrum is well reproduced with a power-law model. The source has neither significant coherent pulsations nor time variabilities. Its luminosity and spectrum remind us that the source might be a pulsar and/or pulsar wind nebula in DEM L241. The spectra of Head and Tail are well reproduced by a non-equilibrium ionization plasma model with over-abundant Ne and under-abundant Fe, suggesting that the progenitor of DEM L241 is a very massive star.

  17. Assessment of the watershed DEM mesh size influence on a large dam design hydrograph

    NASA Astrophysics Data System (ADS)

    Mineo, C.; Sebastianelli, S.; Marinucci, L.; Russo, F.

    2017-07-01

    The present study aims to assess the digital elevation model (DEM) resolution influence on the peak flow estimation for the design hydrograph of a large dam. This was executed by comparing the design hydrograph peak flows, with respect to a 2000years return period, which wereestimated for the Pietrarossa dam, in the South-East of Sicily, for different DEM spatial resolutions. The methodology consisted of the watershed extraction from the catchment basin in which the directly wired area belongs. Furthermore, the intensity duration frequency (IDF) curves were estimated starting from the observational time seriescollected by two rain gauges located near the dam. Finally, through a rainfall-runoff transformation, the design hydrographs were obtained by using both the watershed and the IDF curves. Considering different spatial resolutions, it was found that both the peak flow and the total volume decreases as the DEM spatial resolution decreases.

  18. Flow Dynamics of green sand in the DISAMATIC moulding process using Discrete element method (DEM)

    NASA Astrophysics Data System (ADS)

    Hovad, E.; Larsen, P.; Walther, J. H.; Thorborg, J.; Hattel, J. H.

    2015-06-01

    The DISAMATIC casting process production of sand moulds is simulated with DEM (discrete element method). The main purpose is to simulate the dynamics of the flow of green sand, during the production of the sand mould with DEM. The sand shot is simulated, which is the first stage of the DISAMATIC casting process. Depending on the actual casting geometry the mould can be geometrically quite complex involving e.g. shadowing effects and this is directly reflected in the sand flow during the moulding process. In the present work a mould chamber with “ribs” at the walls is chosen as a baseline geometry to emulate some of these important conditions found in the real moulding process. The sand flow is simulated with the DEM and compared with corresponding video footages from the interior of the chamber during the moulding process. The effect of the rolling resistance and the static friction coefficient is analysed and discussed in relation to the experimental findings.

  19. GPS-Based Precision Baseline Reconstruction for the TanDEM-X SAR-Formation

    NASA Technical Reports Server (NTRS)

    Montenbruck, O.; vanBarneveld, P. W. L.; Yoon, Y.; Visser, P. N. A. M.

    2007-01-01

    The TanDEM-X formation employs two separate spacecraft to collect interferometric Synthetic Aperture Radar (SAR) measurements over baselines of about 1 km. These will allow the generation ofa global Digital Elevation Model (DEM) with an relative vertical accuracy of 2-4 m and a 10 m ground resolution. As part of the ground processing, the separation of the SAR antennas at the time of each data take must be reconstructed with a 1 mm accuracy using measurements from two geodetic grade GPS receivers. The paper discusses the TanDEM-X mission as well as the methods employed for determining the interferometric baseline with utmost precision. Measurements collected during the close fly-by of the two GRACE satellites serve as a reference case to illustrate the processing concept, expected accuracy and quality control strategies.

  20. FEM × DEM: a new efficient multi-scale approach for geotechnical problems with strain localization

    NASA Astrophysics Data System (ADS)

    Nguyen, Trung Kien; Claramunt, Albert Argilaga; Caillerie, Denis; Combe, Gaël; Dal Pont, Stefano; Desrues, Jacques; Richefeu, Vincent

    2017-06-01

    The paper presents a multi-scale modeling of Boundary Value Problem (BVP) approach involving cohesive-frictional granular materials in the FEM × DEM multi-scale framework. On the DEM side, a 3D model is defined based on the interactions of spherical particles. This DEM model is built through a numerical homogenization process applied to a Volume Element (VE). It is then paired with a Finite Element code. Using this numerical tool that combines two scales within the same framework, we conducted simulations of biaxial and pressuremeter tests on a cohesive-frictional granular medium. In these cases, it is known that strain localization does occur at the macroscopic level, but since FEMs suffer from severe mesh dependency as soon as shear band starts to develop, the second gradient regularization technique has been used. As a consequence, the objectivity of the computation with respect to mesh dependency is restored.

  1. Internationalizing Practical ChE Education: The M.I.T. Practice School in Japan.

    ERIC Educational Resources Information Center

    O'Connor, Andrea J.; Kandas, Angelo W.; Natori, Yukikazu; Hatton, T. Alan

    1999-01-01

    Describes the establishment, benefits, and difficulties of an overseas branch of the Massachusetts Institute of Technology's (MIT) chemical engineering Practice School for student internship study at the Mitsubishi Chemical Corporation's Mizushima Plant in Kurashiki, Japan. (WRM)

  2. A framework for global terrain classification using 250-m DEMs to predict geohazards

    NASA Astrophysics Data System (ADS)

    Iwahashi, J.; Matsuoka, M.; Yong, A.

    2016-12-01

    Geomorphology is key for identifying factors that control geohazards induced by landslides, liquefaction, and ground shaking. To systematically identify landforms that affect these hazards, Iwahashi and Pike (2007; IP07) introduced an automated terrain classification scheme using 1-km-scale Shuttle Radar Topography Mission (SRTM) digital elevation models (DEMs). The IP07 classes describe 16 categories of terrain types and were used as a proxy for predicting ground motion amplification (Yong et al., 2012; Seyhan et al., 2014; Stewart et al., 2014; Yong, 2016). These classes, however, were not sufficiently resolved because coarse-scaled SRTM DEMs were the basis for the categories (Yong, 2016). Thus, we develop a new framework consisting of more detailed polygonal global terrain classes to improve estimations of soil-type and material stiffness. We first prepare high resolution 250-m DEMs derived from the 2010 Global Multi-resolution Terrain Elevation Data (GMTED2010). As in IP07, we calculate three geometric signatures (slope, local convexity and surface texture) from the DEMs. We create additional polygons by using the same signatures and multi-resolution segmentation techniques on the GMTED2010. We consider two types of surface texture thresholds in different window sizes (3x3 and 13x13 pixels), in addition to slope and local convexity, to classify pixels within the DEM. Finally, we apply the k-means clustering and thresholding methods to the 250-m DEM and produce more detailed polygonal terrain classes. We compare the new terrain classification maps of Japan and California with geologic, aerial photography, and landslide distribution maps, and visually find good correspondence of key features. To predict ground motion amplification, we apply the Yong (2016) method for estimating VS30. The systematic classification of geomorphology has the potential to provide a better understanding of the susceptibility to geohazards, which is especially vital in populated areas.

  3. TanDEM-X: A radar interferometer with two formation-flying satellites

    NASA Astrophysics Data System (ADS)

    Krieger, Gerhard; Zink, Manfred; Bachmann, Markus; Bräutigam, Benjamin; Schulze, Daniel; Martone, Michele; Rizzoli, Paola; Steinbrecher, Ulrich; Walter Antony, John; De Zan, Francesco; Hajnsek, Irena; Papathanassiou, Kostas; Kugler, Florian; Rodriguez Cassola, Marc; Younis, Marwan; Baumgartner, Stefan; López-Dekker, Paco; Prats, Pau; Moreira, Alberto

    2013-08-01

    TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements) is an innovative formation-flying radar mission that opens a new era in spaceborne radar remote sensing. The primary objective is the acquisition of a global digital elevation model (DEM) with unprecedented accuracy (12 m horizontal resolution and 2 m relative height accuracy). This goal is achieved by extending the TerraSAR-X synthetic aperture radar (SAR) mission by a second, TerraSAR-X like satellite (TDX) flying in close formation with TerraSAR-X (TSX). Both satellites form together a large single-pass SAR interferometer with the opportunity for flexible baseline selection. This enables the acquisition of highly accurate cross-track interferograms without the inherent accuracy limitations imposed by repeat-pass interferometry due to temporal decorrelation and atmospheric disturbances. Besides the primary goal of the mission, several secondary mission objectives based on along-track interferometry as well as new bistatic and multistatic SAR techniques have been defined, representing an important and innovative asset of the TanDEM-X mission. TanDEM-X is implemented in the framework of a public-private partnership between the German Aerospace Center (DLR) and EADS Astrium GmbH. The TanDEM-X satellite was successfully launched in June 2010 and the mission started its operational data acquisition in December 2010. This paper provides an overview of the TanDEM-X mission and summarizes its actual status and performance. Furthermore, results from several scientific radar experiments are presented that show the great potential of future formation-flying interferometric SAR missions to serve novel remote sensing applications.

  4. Discrete Element Method (DEM) Application to The Cone Penetration Test Using COUPi Model

    NASA Astrophysics Data System (ADS)

    Kulchitsky, A. V.; Johnson, J.; Wilkinson, A.; DeGennaro, A. J.; Duvoy, P.

    2011-12-01

    The cone penetration test (CPT) is a soil strength measurement method to determine the tip resistance and sleeve friction versus depth while pushing a cone into regolith with controlled slow quasi-static speed. This test can also be used as an excellent tool to validate the discrete element method (DEM) model by comparing tip resistance and sleeve friction from experiments to model results. DEM by nature requires significant computational resources even for a limited number of particles. Thus, it is important to find particle and ensemble parameters that produce valuable results within reasonable computation times. The Controllable Objects Unbounded Particles Interaction (COUPi) model is a general physical DEM code being developed to model machine/regolith interactions as part of a NASA Lunar Science Institute sponsored project on excavation and mobility modeling. In this work, we consider how different particle shape and size distributions defined in the DEM influence the cone tip and friction sleeve resistance in a CPT DEM simulation. The results are compared to experiments with cone penetration in JSC-1A lunar regolith simulant. The particle shapes include spherical particles, particles composed from the union of three spheres, and some simple polyhedra. This focus is driven by the soil mechanics rule of thumb that particle size and shape distributions are the two most significant factors affecting soil strength. In addition to the particle properties, the packing configuration of an ensemble strongly affects soil strength. Bulk density of the regolith is an important characteristic that significantly influences the tip resistance and sleeve friction (Figure 1). We discuss different approaches used to control granular density in the DEM, including how to obtain higher bulk densities, using numerical "shaking" techniques and varying the friction coefficient during computations.

  5. Quality assessment of Digital Elevation Model (DEM) in view of the Altiplano hydrological modeling

    NASA Astrophysics Data System (ADS)

    Satgé, F.; Arsen, A.; Bonnet, M.; Timouk, F.; Calmant, S.; Pilco, R.; Molina, J.; Lavado, W.; Crétaux, J.; HASM

    2013-05-01

    Topography is crucial data input for hydrological modeling but in many regions of the world, the only way to characterize topography is the use of satellite-based Digital Elevation Models (DEM). In some regions, the quality of these DEMs remains poor and induces modeling errors that may or not be compensated by model parameters tuning. In such regions, the evaluation of these data uncertainties is an important step in the modeling procedure. In this study, which focuses on the Altiplano region, we present the evaluation of the two freely available DEM. The shuttle radar topographic mission (SRTM), a product of the National Aeronautics and Space Administration (NASA) and the Advanced Space Born Thermal Emission and Reflection Global Digital Elevation Map (ASTER GDEM), data provided by the Ministry of Economy, Trade and Industry of Japan (MESI) in collaboration with the NASA, are widely used. While the first represents a resolution of 3 arc seconds (90m) the latter is 1 arc second (30m). In order to select the most reliable DEM, we compared the DEM elevation with high qualities control points elevation. Because of its large spatial coverture (track spaced of 30 km with a measure of each 172 m) and its high vertical accuracy which is less than 15 cm in good weather conditions, the Geoscience Laser Altimeter System (GLAS) on board on the Ice, Cloud and Land elevation Satellite of NASA (ICESat) represent the better solution to establish a high quality elevation database. After a quality check, more than 150 000 ICESat/GLAS measurements are suitable in terms of accuracy for the Altiplano watershed. This data base has been used to evaluate the vertical accuracy for each DEM. Regarding to the full spatial coverture; the comparison has been done for both, all kind of land coverture, range altitude and mean slope.

  6. The Effect of DEM Quality on Sea Level Rise Exposure Analysis

    NASA Astrophysics Data System (ADS)

    Kulp, S. A.; Strauss, B.

    2015-12-01

    Sea level rise (SLR) caused by climate change could cause significant disruptions in coastal communities across the world. Current projections estimate that we may see in the vicinity of 1 meter of SLR by the end of the century, and due to collapsing ice sheets in West Antarctica, more than 3 meters of global SLR appear very likely in the long run. It is therefore crucial that we begin to accurately understand both the short- and long-term effects this level of flooding could have on each country's land area and population. However, while we have high-resolution digital elevation models (DEMs) publicly available for some parts of the world, such as the coastal lidar datasets distributed by NOAA for the US, most of the rest of the world is only covered by much poorer-quality data, such as data from SRTM (3 arcsec, or roughly 90m, horizontal resolution). In this work, we perform SLR analysis using both NOAA lidar- and SRTM-derived DEMs in the United States, in order to understand how using low-quality DEMs affect the final analysis results. We find that in many states, the computed population exposure at 1 meter SLR is over 2x higher when using the Lidar DEM, compared to the results computed from SRTM. In addition to the clear differences in horizontal resolution, this very large difference in computed exposure could likely be explained by the fact that SRTM is based on surface elevation, while the Lidar DEM is based on bare earth elevation. We therefore conclude that any worldwide SLR analysis using SRTM would produce exposure estimates that are far too low, and higher-quality global DEMs are necessary in order to generate exposure analysis of reasonable accuracy.

  7. MIT Lincoln Laboratory Annual Report 2008: Technology in Support of National Security

    DTIC Science & Technology

    2008-01-01

    at MIT Lincoln Laboratory MIT news Program spurs students to pursue scientific careers January 4, 2008 Dan Gabriner asks students to solve a...high-school students to pursue careers in science, technology, engineering, and math, Lincoln Laboratory hires local teachers every summer to work...prevents airplanes from crashing into one another while landing.” The long-term goals of LIFT2 are to entice students to pursue a technical career and

  8. MIT Laboratory for Computer Science Progress Report, July 1984-June 1985

    DTIC Science & Technology

    1985-06-01

    34 Office of Naval Research; " United States Air Force; " United States Army Research Office " MIT controlled IBM funds under an IBM/MIT joint study contract...Current Status 127 5. Future Plans 127 6. Resources and Participants 128 PROGRAMMING METHODOLOGY 129 1. Overview . 130 2. Implementation 130 3...include the use of computers in the educational process by the 1 ducational Computing Group; the use of interconnected computers for planning ; as well gs

  9. Echtzeit-Ultraschallsimulation auf Grafik-Prozessoren mit CUDA

    NASA Astrophysics Data System (ADS)

    Reichl, Tobias; Passenger, Josh; Acosta, Oscar; Salvado, Olivier

    Trotz der zunehmenden Verbreitung jüngerer bildgebender Verfahren bleibt medizinischer Ultraschall (US) weiterhin ein wichtiges Hilfsmittel bei chirurgischen Eingriffen und der klinischen Diagnose. Viele US-gestützte medizinische Prozeduren erfordern allerdings ausgiebiges Training, so dass es wünschenswert ist, eine realistische Simulation von US-Bildern zur Verfügung zu stellen. Im Gegensatz zu früheren Ansätzen simulieren wir solche Bilder auf der "Graphics Processing Unit“. Wir erweitern hierzu eine Methode, die von Wein et al. für die Abschätzung von US-Reflexionen aus Daten der Computertomographie (CT) vorgeschlagen wurde, zu einer leichter zu berechnenden Form. Zusätzlich schätzen wir die US-Absorption aus den CT-Daten ab. Mit Hilfe von NVIDIAs "Compute Unified Device Architecture“ (CUDA) simulieren wir Reflexion, Verschattung, Rauschen und radiale Unschärfe, ausgehend von unbearbeiteten CT-Daten in Echtzeit und ohne Vorausberechnung.

  10. Educational Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Thomas, P.; Rivenberg, P.; Censabella, V.

    2002-11-01

    At the MIT PSFC, student and staff volunteers work together to increase the public's knowledge of fusion science and plasma technology. Seeking to generate excitement in young people about science and engineering, the PSFC hosts a number of educational outreach activities throughout the year, including Middle and High School Outreach Days. The PSFC also has an in-school science-demonstration program on the theme of magnetism. As ``Mr. Magnet," Technical Supervisor Paul Thomas brings a truck-load of hands-on demonstrations to K-12 schools, challenging students to help him with experiments. While teaching fundamentals of magnetism and electricity he shows that science is fun for all, and that any student can have a career in science. This year he reached 82 schools -- 30,000 teachers and students. He has recently expanded his teaching to include an interactive demonstration of plasma, encouraging participants to investigate plasma properties with audiovisual, electromagnetic, and spectroscopic techniques. He has also developed a workshop for middle school on how to build an electromagnet.

  11. Educational Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, Paul; Thomas, Paul

    2006-10-01

    At the MIT PSFC, student and staff volunteers work together to increase the public's knowledge of fusion science and plasma technology. Seeking to generate excitement in young people about science and engineering, the PSFC hosts a number of educational outreach activities throughout the year, including Middle and High School Outreach Days. The PSFC also has an in-school science demonstration program on the theme of magnetism. The Mr. Magnet Program, headed by Mr. Paul Thomas, has been bringing lively demonstrations on magnetism into local elementary and middle schools for 15 years. This year Mr. Magnet presented the program to nearly 30,000 students at over 67 schools and other events, reaching kindergartners through college freshmen. In addition to his program on magnetism, he is offering an interactive lecture about plasma to high schools. The "Traveling Plasma Lab" encourages students to learn more about plasma science while having fun investigating plasma properties using actual laboratory techniques and equipment. Beyond the classroom, Paul Thomas has provided technical training for Boston Museum of Science staff in preparation for the opening of a Star Wars exhibit. His hands-on demos have also been filmed by the History Channel for a one-hour program about Magnetism, which aired in June 2006.

  12. Developmental Eye Movement (DEM) Test Norms for Mandarin Chinese-Speaking Chinese Children.

    PubMed

    Xie, Yachun; Shi, Chunmei; Tong, Meiling; Zhang, Min; Li, Tingting; Xu, Yaqin; Guo, Xirong; Hong, Qin; Chi, Xia

    2016-01-01

    The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool to screen and diagnose reading problems at the onset. No established norm exists for using the DEM test with Mandarin Chinese-speaking Chinese children. This study aims to establish the normative values of the DEM test for the Mandarin Chinese-speaking population in China; it also aims to compare the values with three other published norms for English-, Spanish-, and Cantonese-speaking Chinese children. A random stratified sampling method was used to recruit children from eight kindergartens and eight primary schools in the main urban and suburban areas of Nanjing. A total of 1,425 Mandarin Chinese-speaking children aged 5 to 12 years took the DEM test in Mandarin Chinese. A digital recorder was used to record the process. All of the subjects completed a symptomatology survey, and their DEM scores were determined by a trained tester. The scores were computed using the formula in the DEM manual, except that the "vertical scores" were adjusted by taking the vertical errors into consideration. The results were compared with the three other published norms. In our subjects, a general decrease with age was observed for the four eye movement indexes: vertical score, adjusted horizontal score, ratio, and total error. For both the vertical and adjusted horizontal scores, the Mandarin Chinese-speaking children completed the tests much more quickly than the norms for English- and Spanish-speaking children. However, the same group completed the test slightly more slowly than the norms for Cantonese-speaking children. The differences in the means were significant (P<0.001) in all age groups. For several ages, the scores obtained in this study were significantly different from the reported scores of Cantonese-speaking Chinese children (P<0.005). Compared with English-speaking children, only the vertical score of the 6-year-old group, the vertical-horizontal time

  13. Stochastic Discrete Equation Method (sDEM) for two-phase flows

    SciTech Connect

    Abgrall, R.; Congedo, P.M.; Geraci, G.; Rodio, M.G.

    2015-10-15

    A new scheme for the numerical approximation of a five-equation model taking into account Uncertainty Quantification (UQ) is presented. In particular, the Discrete Equation Method (DEM) for the discretization of the five-equation model is modified for including a formulation based on the adaptive Semi-Intrusive (aSI) scheme, thus yielding a new intrusive scheme (sDEM) for simulating stochastic two-phase flows. Some reference test-cases are performed in order to demonstrate the convergence properties and the efficiency of the overall scheme. The propagation of initial conditions uncertainties is evaluated in terms of mean and variance of several thermodynamic properties of the two phases.

  14. Developmental Eye Movement (DEM) Test Norms for Mandarin Chinese-Speaking Chinese Children

    PubMed Central

    Tong, Meiling; Zhang, Min; Li, Tingting; Xu, Yaqin; Guo, Xirong; Hong, Qin; Chi, Xia

    2016-01-01

    The Developmental Eye Movement (DEM) test is commonly used as a clinical visual-verbal ocular motor assessment tool to screen and diagnose reading problems at the onset. No established norm exists for using the DEM test with Mandarin Chinese-speaking Chinese children. This study aims to establish the normative values of the DEM test for the Mandarin Chinese-speaking population in China; it also aims to compare the values with three other published norms for English-, Spanish-, and Cantonese-speaking Chinese children. A random stratified sampling method was used to recruit children from eight kindergartens and eight primary schools in the main urban and suburban areas of Nanjing. A total of 1,425 Mandarin Chinese-speaking children aged 5 to 12 years took the DEM test in Mandarin Chinese. A digital recorder was used to record the process. All of the subjects completed a symptomatology survey, and their DEM scores were determined by a trained tester. The scores were computed using the formula in the DEM manual, except that the “vertical scores” were adjusted by taking the vertical errors into consideration. The results were compared with the three other published norms. In our subjects, a general decrease with age was observed for the four eye movement indexes: vertical score, adjusted horizontal score, ratio, and total error. For both the vertical and adjusted horizontal scores, the Mandarin Chinese-speaking children completed the tests much more quickly than the norms for English- and Spanish-speaking children. However, the same group completed the test slightly more slowly than the norms for Cantonese-speaking children. The differences in the means were significant (P<0.001) in all age groups. For several ages, the scores obtained in this study were significantly different from the reported scores of Cantonese-speaking Chinese children (P<0.005). Compared with English-speaking children, only the vertical score of the 6-year-old group, the vertical

  15. On the choice of a phase interchange strategy for a multiscale DEM-VOF method

    NASA Astrophysics Data System (ADS)

    Pozzetti, Gabriele; Peters, Bernhard

    2017-07-01

    In this work a novel Multiscale DEM-VOF method is adopted to study three phase flows. It consists in solving the fluid momentum, mass conservation and the phase advection at a different scale with respect to the fluid-particle coupling problem. This allows the VOF scheme to resolve smaller fluid structures than a classic DEM-VOF method, and opens the possibility of adopting different volume interchange techniques. Two different volume interchange techniques are here described and compared with reference to high and low particle concentration scenarios. Considerations about the respective computational costs are also proposed.

  16. The Mi-2 Homolog Mit1 Actively Positions Nucleosomes within Heterochromatin To Suppress Transcription

    PubMed Central

    Creamer, Kevin M.; Job, Godwin; Shanker, Sreenath; Neale, Geoffrey A.; Lin, Yuan-chi; Bartholomew, Blaine

    2014-01-01

    Mit1 is the putative chromatin remodeling subunit of the fission yeast Snf2/histone deacetylase (HDAC) repressor complex (SHREC) and is known to repress transcription at regions of heterochromatin. However, how Mit1 modifies chromatin to silence transcription is largely unknown. Here we report that Mit1 mobilizes histone octamers in vitro and requires ATP hydrolysis and conserved chromatin tethering domains, including a previously unrecognized chromodomain, to remodel nucleosomes and silence transcription. Loss of Mit1 remodeling activity results in nucleosome depletion at specific DNA sequences that display low intrinsic affinity for the histone octamer, but its contribution to antagonizing RNA polymerase II (Pol II) access and transcription is not restricted to these sites. Genetic epistasis analyses demonstrate that SHREC subunits and the transcription-coupled Set2 histone methyltransferase, which is involved in suppression of cryptic transcription at actively transcribed regions, cooperate to silence heterochromatic transcripts. In addition, we have demonstrated that Mit1's remodeling activity contributes to SHREC function independently of Clr3's histone deacetylase activity on histone H3 K14. We propose that Mit1 is a chromatin remodeling factor that cooperates with the Clr3 histone deacetylase of SHREC and other chromatin modifiers to stabilize heterochromatin structure and to prevent access to the transcriptional machinery. PMID:24662054

  17. LULC Classification and Topographic Correction of Landsat-7 ETM+ Imagery in the Yangjia River Watershed: the Influence of DEM Resolution.

    PubMed

    Gao, Yongnian; Zhang, Wanchang

    2009-01-01

    DEM-based topographic corrections on Landsat-7 ETM+ imagery from rugged terrain, as an effective processing techniques to improve the accuracy of Land Use/Land Cover (LULC) classification as well as land surface parameter retrievals with remotely sensed data, has been frequently reported in the literature. However, few studies have investigated the exact effects of DEM with different resolutions on the correction of imagery. Taking the topographic corrections on the Landsat-7 ETM+ images acquired from the rugged terrain of the Yangjiahe river basin (P.R. China) as an example, the present work systematically investigates such issues by means of two commonly used topographic correction algorithms with the support of different spatial resolution DEMs. After the pre-processing procedures, i.e. atmospheric correction and geo-registration, were applied to the ETM+ images, two topographic correction algorithms, namely SCS correction and Minnaert correction, were applied to assess the effects of different spatial resolution DEMs obtained from two sources in the removal of topographic effects and LULC classifications. The results suggested that the topographic effects were tremendously reduced with these two algorithms under the support of different spatial resolution DEMs, and the performance of the topographic correction with the 1:50,000-topographic-map DEM was similar to that achieved using SRTM DEM. Moreover, when the same topographic correction algorithm was applied the accuracy of LULC classification after topographic correction based on 1:50,000-topographic-map DEM was similar as that based on SRTM DEM, which implies that the 90 m SRTM DEM can be used as an alternative for the topographic correction of ETM+ imagery when high resolution DEM is unavailable.

  18. LULC Classification and Topographic Correction of Landsat-7 ETM+ Imagery in the Yangjia River Watershed: the Influence of DEM Resolution

    PubMed Central

    Gao, Yongnian; Zhang, Wanchang

    2009-01-01

    DEM-based topographic corrections on Landsat-7 ETM+ imagery from rugged terrain, as an effective processing techniques to improve the accuracy of Land Use/Land Cover (LULC) classification as well as land surface parameter retrievals with remotely sensed data, has been frequently reported in the literature. However, few studies have investigated the exact effects of DEM with different resolutions on the correction of imagery. Taking the topographic corrections on the Landsat-7 ETM+ images acquired from the rugged terrain of the Yangjiahe river basin (P.R. China) as an example, the present work systematically investigates such issues by means of two commonly used topographic correction algorithms with the support of different spatial resolution DEMs. After the pre-processing procedures, i.e. atmospheric correction and geo-registration, were applied to the ETM+ images, two topographic correction algorithms, namely SCS correction and Minnaert correction, were applied to assess the effects of different spatial resolution DEMs obtained from two sources in the removal of topographic effects and LULC classifications. The results suggested that the topographic effects were tremendously reduced with these two algorithms under the support of different spatial resolution DEMs, and the performance of the topographic correction with the 1:50,000-topographic-map DEM was similar to that achieved using SRTM DEM. Moreover, when the same topographic correction algorithm was applied the accuracy of LULC classification after topographic correction based on 1:50,000-topographic-map DEM was similar as that based on SRTM DEM, which implies that the 90 m SRTM DEM can be used as an alternative for the topographic correction of ETM+ imagery when high resolution DEM is unavailable. PMID:22573996

  19. Influence of Lossy Compressed DEM on Radiometric Correction for Land Cover Classification of Remote Sensing Images

    NASA Astrophysics Data System (ADS)

    Moré, G.; Pesquer, L.; Blanes, I.; Serra-Sagristà, J.; Pons, X.

    2012-12-01

    World coverage Digital Elevation Models (DEM) have progressively increased their spatial resolution (e.g., ETOPO, SRTM, or Aster GDEM) and, consequently, their storage requirements. On the other hand, lossy data compression facilitates accessing, sharing and transmitting large spatial datasets in environments with limited storage. However, since lossy compression modifies the original information, rigorous studies are needed to understand its effects and consequences. The present work analyzes the influence of DEM quality -modified by lossy compression-, on the radiometric correction of remote sensing imagery, and the eventual propagation of the uncertainty in the resulting land cover classification. Radiometric correction is usually composed of two parts: atmospheric correction and topographical correction. For topographical correction, DEM provides the altimetry information that allows modeling the incidence radiation on terrain surface (cast shadows, self shadows, etc). To quantify the effects of the DEM lossy compression on the radiometric correction, we use radiometrically corrected images for classification purposes, and compare the accuracy of two standard coding techniques for a wide range of compression ratios. The DEM has been obtained by resampling the DEM v.2 of Catalonia (ICC), originally having 15 m resolution, to the Landsat TM resolution. The Aster DEM has been used to fill the gaps beyond the administrative limits of Catalonia. The DEM has been lossy compressed with two coding standards at compression ratios 5:1, 10:1, 20:1, 100:1 and 200:1. The employed coding standards have been JPEG2000 and CCSDS-IDC; the former is an international ISO/ITU-T standard for almost any type of images, while the latter is a recommendation of the CCSDS consortium for mono-component remote sensing images. Both techniques are wavelet-based followed by an entropy-coding stage. Also, for large compression ratios, both techniques need a post processing for correctly

  20. San Francisco Bay-Delta bathymetric/topographic digital elevation model (DEM)

    USGS Publications Warehouse

    Fregoso, Theresa; Wang, Rueen-Fang; Ateljevich, Eli; Jaffe, Bruce E.

    2017-01-01

    A high-resolution (10-meter per pixel) digital elevation model (DEM) was created for the Sacramento-San Joaquin Delta using both bathymetry and topography data. This DEM is the result of collaborative efforts of the U.S. Geological Survey (USGS) and the California Department of Water Resources (DWR). The base of the DEM is from a 10-m DEM released in 2004 and updated in 2005 (Foxgrover and others, 2005) that used Environmental Systems Research Institute (ESRI), ArcGIS Topo to Raster module to interpolate grids from single beam bathymetric surveys collected by DWR, the Army Corp of Engineers (COE), the National Oceanic and Atmospheric Administration (NOAA), and the USGS, into a continuous surface. The Topo to Raster interpolation method was specifically designed to create hydrologically correct DEMs from point, line, and polygon data (Environmental Systems Research Institute, Inc., 2015). Elevation contour lines were digitized based on the single beam point data for control of channel morphology during the interpolation process. Checks were performed to ensure that the interpolated surfaces honored the source bathymetry, and additional contours and (or) point data were added as needed to help constrain the data. The original data were collected in the tidal datum Mean Lower or Low Water (MLLW) or the National Geodetic Vertical Datum of 1929 (NGVD29). All data were converted to NGVD29.The 2005 USGS DEM was updated by DWR, first by converting the DEM to the current modern datum of North American Vertical Datum of 1988 (NAVD88) and then by following the methodology of the USGS DEM, established for the 2005 DEM (Foxgrover and others, 2005) for adding newly collected single and multibeam bathymetric data. They then included topographic data from lidar surveys, providing the first DEM that included the land/water interface (Wang and Ateljevich, 2012).The USGS further updated and expanded the DWR DEM with the inclusion of USGS interpolated sections of single beam

  1. High-Accuracy Tidal Flat Digital Elevation Model Construction Using TanDEM-X Science Phase Data

    NASA Technical Reports Server (NTRS)

    Lee, Seung-Kuk; Ryu, Joo-Hyung

    2017-01-01

    This study explored the feasibility of using TanDEM-X (TDX) interferometric observations of tidal flats for digital elevation model (DEM) construction. Our goal was to generate high-precision DEMs in tidal flat areas, because accurate intertidal zone data are essential for monitoring coastal environment sand erosion processes. To monitor dynamic coastal changes caused by waves, currents, and tides, very accurate DEMs with high spatial resolution are required. The bi- and monostatic modes of the TDX interferometer employed during the TDX science phase provided a great opportunity for highly accurate intertidal DEM construction using radar interferometry with no time lag (bistatic mode) or an approximately 10-s temporal baseline (monostatic mode) between the master and slave synthetic aperture radar image acquisitions. In this study, DEM construction in tidal flat areas was first optimized based on the TDX system parameters used in various TDX modes. We successfully generated intertidal zone DEMs with 57-m spatial resolutions and interferometric height accuracies better than 0.15 m for three representative tidal flats on the west coast of the Korean Peninsula. Finally, we validated these TDX DEMs against real-time kinematic-GPS measurements acquired in two tidal flat areas; the correlation coefficient was 0.97 with a root mean square error of 0.20 m.

  2. Tropical-forest biomass estimation at X-Band from the spaceborne TanDEM-X interferometer

    Treesearch

    R. Treuhaft; F. Goncalves; J.R. dos Santos; M. Keller; M. Palace; S.N. Madsen; F. Sullivan; P.M.L.A. Graca

    2014-01-01

    This letter reports the sensitivity of X-band interferometric synthetic aperture radar (InSAR) data from the first dual-spacecraft radar interferometer, TanDEM-X, to variations in tropical-forest aboveground biomass (AGB). It also reports the first tropical-forest AGB estimates fromTanDEM-X data. Tropical forests account for...

  3. Evaluating DEM conditioning techniques, elevation source data, and grid resolution for field-scale hydrological parameter extraction

    NASA Astrophysics Data System (ADS)

    Woodrow, Kathryn; Lindsay, John B.; Berg, Aaron A.

    2016-09-01

    Although digital elevation models (DEMs) prove useful for a number of hydrological applications, they are often the end result of numerous processing steps that each contains uncertainty. These uncertainties have the potential to greatly influence DEM quality and to further propagate to DEM-derived attributes including derived surface and near-surface drainage patterns. This research examines the impacts of DEM grid resolution, elevation source data, and conditioning techniques on the spatial and statistical distribution of field-scale hydrological attributes for a 12,000 ha watershed of an agricultural area within southwestern Ontario, Canada. Three conditioning techniques, including depression filling (DF), depression breaching (DB), and stream burning (SB), were examined. The catchments draining to each boundary of 7933 agricultural fields were delineated using the surface drainage patterns modeled from LiDAR data, interpolated to a 1 m, 5 m, and 10 m resolution DEMs, and from a 10 m resolution photogrammetric DEM. The results showed that variation in DEM grid resolution resulted in significant differences in the spatial and statistical distributions of contributing areas and the distributions of downslope flowpath length. Degrading the grid resolution of the LiDAR data from 1 m to 10 m resulted in a disagreement in mapped contributing areas of between 29.4% and 37.3% of the study area, depending on the DEM conditioning technique. The disagreements among the field-scale contributing areas mapped from the 10 m LiDAR DEM and photogrammetric DEM were large, with nearly half of the study area draining to alternate field boundaries. Differences in derived contributing areas and flowpaths among various conditioning techniques increased substantially at finer grid resolutions, with the largest disagreement among mapped contributing areas occurring between the 1 m resolution DB DEM and the SB DEM (37% disagreement) and the DB-DF comparison (36.5% disagreement in mapped

  4. Benchmarking on Tsunami Currents with ComMIT

    NASA Astrophysics Data System (ADS)

    Sharghi vand, N.; Kanoglu, U.

    2015-12-01

    There were no standards for the validation and verification of tsunami numerical models before 2004 Indian Ocean tsunami. Even, number of numerical models has been used for inundation mapping effort, evaluation of critical structures, etc. without validation and verification. After 2004, NOAA Center for Tsunami Research (NCTR) established standards for the validation and verification of tsunami numerical models (Synolakis et al. 2008 Pure Appl. Geophys. 165, 2197-2228), which will be used evaluation of critical structures such as nuclear power plants against tsunami attack. NCTR presented analytical, experimental and field benchmark problems aimed to estimate maximum runup and accepted widely by the community. Recently, benchmark problems were suggested by the US National Tsunami Hazard Mitigation Program Mapping & Modeling Benchmarking Workshop: Tsunami Currents on February 9-10, 2015 at Portland, Oregon, USA (http://nws.weather.gov/nthmp/index.html). These benchmark problems concentrated toward validation and verification of tsunami numerical models on tsunami currents. Three of the benchmark problems were: current measurement of the Japan 2011 tsunami in Hilo Harbor, Hawaii, USA and in Tauranga Harbor, New Zealand, and single long-period wave propagating onto a small-scale experimental model of the town of Seaside, Oregon, USA. These benchmark problems were implemented in the Community Modeling Interface for Tsunamis (ComMIT) (Titov et al. 2011 Pure Appl. Geophys. 168, 2121-2131), which is a user-friendly interface to the validated and verified Method of Splitting Tsunami (MOST) (Titov and Synolakis 1995 J. Waterw. Port Coastal Ocean Eng. 121, 308-316) model and is developed by NCTR. The modeling results are compared with the required benchmark data, providing good agreements and results are discussed. Acknowledgment: The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant

  5. Verantwortlicher Umgang mit Antibiotika: Notwendigkeit der Antibiotikareduktion in der Aknetherapie.

    PubMed

    Gollnick, Harald P M; Buer, Jan; Beissert, Stefan; Sunderkätter, Cord

    2016-12-01

    Der übermäßige oder unkritische weltweite Einsatz von Antibiotika in der Medizin hat die Ausbreitung von Antibiotikaresistenzen beschleunigt. In einigen Bereichen sind viele Antibiotika bei bakteriellen Infektionen, die zuvor noch gut auf antibakterielle Wirkstoffe reagierten, mittlerweile wirkungslos geworden. Dermatologen/Venerologen setzten orale und topische Antibiotika bei der Behandlung von Acne vulgaris routinemäßig ein, obwohl Akne weder eine infektiöse Erkrankung ist noch alleine durch das Propionibacterium getriggert wird. Vielmehr ist sie eine komplexe, chronische entzündliche Hauterkrankung, die durch verschiedene pathogenetische Faktoren wie follikuläre Hyperkeratose, erhöhter Sebumproduktion, bakterielle Proliferation und Entzündung zustande kommt. Folglich sollte eine erfolgreiche Therapie auf die Bekämpfung verschiedener pathogenetischer Faktoren und nicht nur auf die von Propionibacterium acnes abzielen. Daher wurden topische Retinoide und Benzoylperoxid als Mittel der ersten Wahl definiert. Monotherapien mit lokalen Antibiotika sollten insgesamt vermieden werden. Systemische Antibiotika der Tetrazyklin-Gruppe haben bei bestimmen Krankheitsstadien ihren Sinn, ihre Wirkung könnte aber eher auf der antientzündlichen als auf der antibiotischen Reaktion beruhen. Gesundheitsbehörden ermahnen alle Gesundheitsdienstleister, den Einsatz von Antibiotika einzuschränken. Das Nutzen-Risiko-Verhältnis muss bei der Entscheidung für oder gegen eine antibiotische Therapie bei einem einzelnen Patienten immer auch in Bezug auf das öffentliche Interesse am Erhalt der Wirksamkeit von Antibiotika abgewogen werden. Im Folgenden werden das aktuelle Krankheitskonzept zu Acne vulgaris und die sich daraus ableitenden Konsequenzen für den Einsatz von Antibiotika vorgestellt. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  6. Perspective - Synthetic DEMs: A vital underpinning for the quantitative future of landform analysis?

    NASA Astrophysics Data System (ADS)

    Hillier, John K.; Sofia, Giulia; Conway, Susan

    2015-04-01

    Physical processes, including anthropogenic feedbacks, sculpt planetary surfaces (e.g., Earth's). A fundamental tenet of Geomorphology is that the shapes created, when combined with other measurements, can be used to understand those processes. Morphological data, including metrics and mapping (manual and automated), are a key resource in this endeavour. However, how good are these data that analyses rely on? Artificial or synthetic DEMs are widely used to examine the distortions of 'noise' (e.g., on topographic parameters), but only rarely to make strong 'absolute' statements about landform detection and quantification; e.g., 84% of the river channels in the real landscape are found, or 47% of all actual drumlins H > 3 m are mapped. In theory synthetic DEMs a priori containing known, idealised components can give such absolute conclusions regarding effectiveness if they can be constructed so as to represent well the actual landscapes. So, do we need good realistic synthetic DEMs, how can we best construct them, and what for? From our perspective, they are vital to verify the statistics that will link physics-driven models of processes to morphological observations, allowing quantitative hypotheses to be formulated and tested. We will outline current approaches, and some speculations about the future, but we are seeking a discussion on how best to construct realistic synthetic DEMs and proceed with uncertainty-aware landscape analysis to examine physical processes.

  7. Research of the gas-solid flow character based on the DEM method

    NASA Astrophysics Data System (ADS)

    Wang, Xueyao; Xiao, Yunhan

    2011-12-01

    Numerical simulation of gas-solid flow behaviors in a rectangular fluidized bed is carried out three dimensionally by the discrete element method (DEM). Euler method and Lagrange method are employed to deal with the gas phase and solid phase respectively. The collided force among particles, striking force between particle and wall, drag force, gravity, Magnus lift force and Saffman lift force are considered when establishing the mathematic models. Soft-sphere model is used to describe the collision of particles. In addition, the Euler method is also used for modeling the solid phase to compare with the results of DEM. The flow patterns, particle mean velocities, particles' diffusion and pressure drop of the bed under typical operating conditions are obtained. The results show that the DEM method can describe the detailed information among particles, while the Euler-Euler method cannot capture the micro-scale character. No matter which method is used, the diffusion of particles increases with the increase of gas velocity. But the gathering and crushing of particles cannot be simulated, so the energy loss of particles' collision cannot be calculated and the diffusion by using the Euler-Euler method is larger. In addition, it is shown by DEM method, with strengthening of the carrying capacity, more and more particles can be schlepped upward and the dense suspension upflow pattern can be formed. However, the results given by the Euler-Euler method are not consistent with the real situation.

  8. DEM GPU studies of industrial scale particle simulations for granular flow civil engineering applications

    NASA Astrophysics Data System (ADS)

    Pizette, Patrick; Govender, Nicolin; Wilke, Daniel N.; Abriak, Nor-Edine

    2017-06-01

    The use of the Discrete Element Method (DEM) for industrial civil engineering industrial applications is currently limited due to the computational demands when large numbers of particles are considered. The graphics processing unit (GPU) with its highly parallelized hardware architecture shows potential to enable solution of civil engineering problems using discrete granular approaches. We demonstrate in this study the pratical utility of a validated GPU-enabled DEM modeling environment to simulate industrial scale granular problems. As illustration, the flow discharge of storage silos using 8 and 17 million particles is considered. DEM simulations have been performed to investigate the influence of particle size (equivalent size for the 20/40-mesh gravel) and induced shear stress for two hopper shapes. The preliminary results indicate that the shape of the hopper significantly influences the discharge rates for the same material. Specifically, this work shows that GPU-enabled DEM modeling environments can model industrial scale problems on a single portable computer within a day for 30 seconds of process time.

  9. Rockslide and Impulse Wave Modelling in the Vajont Reservoir by DEM-CFD Analyses

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Utili, S.; Crosta, G. B.

    2016-06-01

    This paper investigates the generation of hydrodynamic water waves due to rockslides plunging into a water reservoir. Quasi-3D DEM analyses in plane strain by a coupled DEM-CFD code are adopted to simulate the rockslide from its onset to the impact with the still water and the subsequent generation of the wave. The employed numerical tools and upscaling of hydraulic properties allow predicting a physical response in broad agreement with the observations notwithstanding the assumptions and characteristics of the adopted methods. The results obtained by the DEM-CFD coupled approach are compared to those published in the literature and those presented by Crosta et al. (Landslide spreading, impulse waves and modelling of the Vajont rockslide. Rock mechanics, 2014) in a companion paper obtained through an ALE-FEM method. Analyses performed along two cross sections are representative of the limit conditions of the eastern and western slope sectors. The max rockslide average velocity and the water wave velocity reach ca. 22 and 20 m/s, respectively. The maximum computed run up amounts to ca. 120 and 170 m for the eastern and western lobe cross sections, respectively. These values are reasonably similar to those recorded during the event (i.e. ca. 130 and 190 m, respectively). Therefore, the overall study lays out a possible DEM-CFD framework for the modelling of the generation of the hydrodynamic wave due to the impact of a rapid moving rockslide or rock-debris avalanche.

  10. A simplified DEM-CFD approach for pebble bed reactor simulations

    SciTech Connect

    Li, Y.; Ji, W.

    2012-07-01

    In pebble bed reactors (PBR's), the pebble flow and the coolant flow are coupled with each other through coolant-pebble interactions. Approaches with different fidelities have been proposed to simulate similar phenomena. Coupled Discrete Element Method-Computational Fluid Dynamics (DEM-CFD) approaches are widely studied and applied in these problems due to its good balance between efficiency and accuracy. In this work, based on the symmetry of the PBR geometry, a simplified 3D-DEM/2D-CFD approach is proposed to speed up the DEM-CFD simulation without significant loss of accuracy. Pebble flow is simulated by a full 3-D DEM, while the coolant flow field is calculated with a 2-D CFD simulation by averaging variables along the annular direction in the cylindrical geometry. Results show that this simplification can greatly enhance the efficiency for cylindrical core, which enables further inclusion of other physics such as thermal and neutronic effect in the multi-physics simulations for PBR's. (authors)

  11. 388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    388. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; SUSPENDED STRUCTURE; SIDE SPAN TRUSSES AT ANCHORAGES; CONTRACT NO. 6; DRAWING NO. 40 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  12. 387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF ...

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

    387. D.E.M., Delineator December 1932 STATE OF CALIFORNIA; DEPARTMENT OF PUBLIC WORKS; SAN FRANCISCO - OAKLAND BAY BRIDGE; SUPERSTRUCTURE - WEST BAY CROSSING; TOWERS 2, 3, 5 & 6; BRACING DETAILS - LOWER DECK; CONTRACT NO. 6; DRAWING NO. 27 - San Francisco Oakland Bay Bridge, Spanning San Francisco Bay, San Francisco, San Francisco County, CA

  13. Discrete element modelling (DEM) input parameters: understanding their impact on model predictions using statistical analysis

    NASA Astrophysics Data System (ADS)

    Yan, Z.; Wilkinson, S. K.; Stitt, E. H.; Marigo, M.

    2015-09-01

    Selection or calibration of particle property input parameters is one of the key problematic aspects for the implementation of the discrete element method (DEM). In the current study, a parametric multi-level sensitivity method is employed to understand the impact of the DEM input particle properties on the bulk responses for a given simple system: discharge of particles from a flat bottom cylindrical container onto a plate. In this case study, particle properties, such as Young's modulus, friction parameters and coefficient of restitution were systematically changed in order to assess their effect on material repose angles and particle flow rate (FR). It was shown that inter-particle static friction plays a primary role in determining both final angle of repose and FR, followed by the role of inter-particle rolling friction coefficient. The particle restitution coefficient and Young's modulus were found to have insignificant impacts and were strongly cross correlated. The proposed approach provides a systematic method that can be used to show the importance of specific DEM input parameters for a given system and then potentially facilitates their selection or calibration. It is concluded that shortening the process for input parameters selection and calibration can help in the implementation of DEM.

  14. Extracting DEM from airborne X-band data based on PolInSAR

    NASA Astrophysics Data System (ADS)

    Hou, X. X.; Huang, G. M.; Zhao, Z.

    2015-06-01

    Polarimetric Interferometric Synthetic Aperture Radar (PolInSAR) is a new trend of SAR remote sensing technology which combined polarized multichannel information and Interferometric information. It is of great significance for extracting DEM in some regions with low precision of DEM such as vegetation coverage area and building concentrated area. In this paper we describe our experiments with high-resolution X-band full Polarimetric SAR data acquired by a dual-baseline interferometric airborne SAR system over an area of Danling in southern China. Pauli algorithm is used to generate the double polarimetric interferometry data, Singular Value Decomposition (SVD), Numerical Radius (NR) and Phase diversity (PD) methods are used to generate the full polarimetric interferometry data. Then we can make use of the polarimetric interferometric information to extract DEM with processing of pre filtering , image registration, image resampling, coherence optimization, multilook processing, flat-earth removal, interferogram filtering, phase unwrapping, parameter calibration, height derivation and geo-coding. The processing system named SARPlore has been exploited based on VC++ led by Chinese Academy of Surveying and Mapping. Finally compared optimization results with the single polarimetric interferometry, it has been observed that optimization ways can reduce the interferometric noise and the phase unwrapping residuals, and improve the precision of DEM. The result of full polarimetric interferometry is better than double polarimetric interferometry. Meanwhile, in different terrain, the result of full polarimetric interferometry will have a different degree of increase.

  15. DEM-based Watershed Delineation - Comparison of Different Methods and applications

    NASA Astrophysics Data System (ADS)

    Chu, X.; Zhang, J.; Tahmasebi Nasab, M.

    2015-12-01

    Digital elevation models (DEMs) are commonly used for large-scale watershed hydrologic and water quality modeling. With aid of the latest LiDAR technology, submeter scale DEM data are often available for many areas in the United States. Precise characterization of the detailed variations in surface microtopography using such high-resolution DEMs is crucial to the related watershed modeling. Various methods have been developed to delineate a watershed, including determination of flow directions and accumulations, identification of subbasin boundaries, and calculation of the relevant topographic parameters. The objective of this study is to examine different DEM-based watershed delineation methods by comparing their unique features and the discrepancies in their results. Not only does this study cover the traditional watershed delineation methods, but also a new puddle-based unit (PBU) delineation method. The specific topics and issues to be presented involve flow directions (D8 single flow direction vs. multi-direction methods), segmentation of stream channels, drainage systems (single "depressionless" drainage network vs. hierarchical depression-dominated drainage system), and hydrologic connectivity (static structural connectivity vs. dynamic functional connectivity). A variety of real topographic surfaces are selected and delineated by using the selected methods. Comparisons of their delineation results emphasize the importance of selection of the methods and highlight their applicability and potential impacts on watershed modeling.

  16. Rhode Island DEM to Receive $129,000 EPA Pollution Prevention Grant

    EPA Pesticide Factsheets

    The RI Dept. of Environmental Management (RI DEM) has been selected to receive $129,000 over two years as one of five Pollution Prevention grants being awarded by EPA’s New England Regional Office for the FY2016-FY2017 Pollution Prevention Grants cycle.

  17. A quick algorithm of counting flow accumulation matrix for deriving drainage networks from a DEM

    NASA Astrophysics Data System (ADS)

    Wang, Yanping; Liu, Yonghe; Xie, Hongbo; Xiang, ZhongLin

    2011-06-01

    Computerized auto-extraction of drainage networks from Digital Elevation Model (DEM) has been widely used in hydrological modeling and relevant studies. Several essential procedures need to be implemented in eight-directional(D8) watershed delineation method, among which a problem need to be resolved is the lack of a high efficiency algorithm for quick and accurate computation of flow accumulation matrix involved in river network delineations. For the problem of depression filling, the algorithm presented by Oliver Planchon has resolved it. This study was aimed to develop a simple and quick algorithm for flow accumulation matrix computations. For this purpose, a simple and high efficiency algorithm of the time complexity of O(n) compared to the commonly used code of the time complexity of O(n2) orO(nlogn) , has been developed. Performance tests on this newly developed algorithm were conducted for different size of DEMs, and the results suggested that the algorithm has a linear time complexity with increasing sizes of DEM. The computation efficiency of this newly developed algorithm is many times higher than the commonly used code, and for a DEM of size 1000*1000, flow accumulation matrix computation can be completed within only several seconds compared with about few minutes needed by common used algorithms.

  18. Dem Local Accuracy Patterns in Land-Use/Land-Cover Classification

    NASA Astrophysics Data System (ADS)

    Katerji, Wassim; Farjas Abadia, Mercedes; Morillo Balsera, Maria del Carmen

    2016-01-01

    Global and nation-wide DEM do not preserve the same height accuracy throughout the area of study. Instead of assuming a single RMSE value for the whole area, this study proposes a vario-model that divides the area into sub-regions depending on the land-use / landcover (LULC) classification, and assigns a local accuracy per each zone, as these areas share similar terrain formation and roughness, and tend to have similar DEM accuracies. A pilot study over Lebanon using the SRTM and ASTER DEMs, combined with a set of 1,105 randomly distributed ground control points (GCPs) showed that even though the inputDEMs have different spatial and temporal resolution, and were collected using difierent techniques, their accuracy varied similarly when changing over difierent LULC classes. Furthermore, validating the generated vario-models proved that they provide a closer representation of the accuracy to the validating GCPs than the conventional RMSE, by 94% and 86% for the SRTMand ASTER respectively. Geostatistical analysis of the input and output datasets showed that the results have a normal distribution, which support the generalization of the proven hypothesis, making this finding applicable to other input datasets anywhere around the world.

  19. New land-based method for surveying sandy shores and extracting DEMs: the INSHORE system.

    PubMed

    Baptista, Paulo; Cunha, Telmo R; Matias, Ana; Gama, Cristina; Bernardes, Cristina; Ferreira, Oscar

    2011-11-01

    The INSHORE system (INtegrated System for High Operational REsolution in shore monitoring) is a land-base survey system designed and developed for the specific task of monitoring the evolution in time of sandy shores. This system was developed with two main objectives: (1) to produce highly accurate 3D coordinates of surface points (in the order of 0.02 to 0.03 m); and (2) to be extremely efficient in surveying a beach stretch of several kilometres. Previous tests have demonstrated that INSHORE systems fulfil such objectives. Now, the usefulness of the INSHORE system as a survey tool for the production of Digital Elevation Models (DEMs) of sandy shores is demonstrated. For this purpose, the comparison of DEMs obtained with the INSHORE system and with other relevant survey techniques is presented. This comparison focuses on the final DEM accuracy and also on the survey efficiency and its impact on the costs associated with regular monitoring programmes. The field survey method of the INSHORE system, based on profile networks, has a productivity of about 30 to 40 ha/h, depending on the beach surface characteristics. The final DEM precision, after interpolation of the global positioning system profile network, is approximately 0.08 to 0.12 m (RMS), depending on the profile network's density. Thus, this is a useful method for 3D representation of sandy shore surfaces and can permit, after interpolation, reliable calculations of volume and other physical parameters.

  20. An innovative approach to improve SRTM DEM using multispectral imagery and artificial neural network

    NASA Astrophysics Data System (ADS)

    Wendi, Dadiyorto; Liong, Shie-Yui; Sun, Yabin; doan, Chi Dung

    2016-06-01

    Although the Shuttle Radar Topography Mission [SRTM) data are a publicly accessible Digital Elevation Model [DEM) provided at no cost, its accuracy especially at forested area is known to be limited with root mean square error (RMSE) of approx. 14 m in Singapore's forested area. Such inaccuracy is attributed to the 5.6 cm wavelength used by SRTM that does not penetrate vegetation well. This paper considers forested areas of central catchment of Singapore as a proof of concept of an approach to improve the SRTM data set. The approach makes full use of (1) the introduction of multispectral imagery (Landsat 8), of 30 m resolution, into SRTM data; (2) the Artificial Neural Network (ANN) to flex its known strengths in pattern recognition and; (3) a reference DEM of high accuracy (1 m) derived through the integration of stereo imaging of worldview-1 and extensive ground survey points. The study shows a series of significant improvements of the SRTM when assessed with the reference DEM of 2 different areas, with RMSE reduction of ˜68% (from 13.9 m to 4.4 m) and ˜52% (from 14.2 m to 6.7 m). In addition, the assessment of the resulting DEM also includes comparisons with simple denoising methodology (Low Pass Filter) and commercially available product called NEXTMap® World 30™.

  1. DEM sourcing guidelines for computing 1 Eö accurate terrain corrections for airborne gravity gradiometry

    NASA Astrophysics Data System (ADS)

    Annecchione, Maria; Hatch, David; Hefford, Shane W.

    2017-01-01

    In this paper we investigate digital elevation model (DEM) sourcing requirements to compute gravity gradiometry terrain corrections accurate to 1 Eötvös (Eö) at observation heights of 80 m or more above ground. Such survey heights are typical in fixed-wing airborne surveying for resource exploration where the maximum signal-to-noise ratio is sought. We consider the accuracy of terrain corrections relevant for recent commercial airborne gravity gradiometry systems operating at the 10 Eö noise level and for future systems with a target noise level of 1 Eö. We focus on the requirements for the vertical gradient of the vertical component of gravity (Gdd) because this element of the gradient tensor is most commonly interpreted qualitatively and quantitatively. Terrain correction accuracy depends on the bare-earth DEM accuracy and spatial resolution. The bare-earth DEM accuracy and spatial resolution depends on its source. Two possible sources are considered: airborne LiDAR and Shuttle Radar Topography Mission (SRTM). The accuracy of an SRTM DEM is affected by vegetation height. The SRTM footprint is also larger and the DEM resolution is thus lower. However, resolution requirements relax as relief decreases. Publicly available LiDAR data and 1 arc-second and 3 arc-second SRTM data were selected over four study areas representing end member cases of vegetation cover and relief. The four study areas are presented as reference material for processing airborne gravity gradiometry data at the 1 Eö noise level with 50 m spatial resolution. From this investigation we find that to achieve 1 Eö accuracy in the terrain correction at 80 m height airborne LiDAR data are required even when terrain relief is a few tens of meters and the vegetation is sparse. However, as satellite ranging technologies progress bare-earth DEMs of sufficient accuracy and resolution may be sourced at lesser cost. We found that a bare-earth DEM of 10 m resolution and 2 m accuracy are sufficient for

  2. Effect of DEM resolution and comparison between different weighting factors for hydrologic connectivity index

    NASA Astrophysics Data System (ADS)

    Cantreul, Vincent; Cavalli, Marco; Degré, Aurore

    2016-04-01

    The emerging concept of hydrological connectivity is difficult to quantify. Some indices have been proposed. The most cited is Borselli's one. It mainly uses the DEM as input. The pixel size may strongly impacts the result of the calculation. It has not been studied yet in silty areas. Another important aspect is the choice of the weighting factor which strongly influences the index value. The objective of this poster is so to compare 8 different DEM's resolutions (12, 24, 48, 72, 96, 204, 504 and 996cm) and 3 different weighting factors (factor C of Wischmeier, Manning's factor and rugosity index) in the Borselli's index calculation. The IC was calculated in a 124ha catchment (Hevillers), in the loess belt, in Belgium. The DEM used is coming from a UAV with a maximum resolution of 12 cm. Permanent covered surfaces are not considered in order to avoid artefact due to the vegetation (2% of the surface). Regarding the DEM pixel size, the IC increases for a given pixel when the pixel size decreases. That confirms some results observed in the Alpine region by Cavalli (2014). The mean difference between 12 cm and 10 m resolution is 35% with higher values up to 100% for higher connectivity zones (flow paths). Another result is the lower impact of connections in the watershed (grass strips…) at lower pixel sizes. This is linked to the small width of some connections which are sometimes comparing to cell size. Furthermore, a great loss of precision is observed from the 500 cm pixel size and upper. That remark is quite intuitive. Finally, some very well disconnected zones appear for the highest resolutions. Regarding the weighting factor, IC values calculated using C factor are lower than with the rugosity index which is only a topographic factor. With very high resolution DEM, it permits to represent the fine topography. For the C factor, the zones up to very well disconnected areas (grass strips, wood…) are well represented with lower index values than downstream

  3. Long-lived mitochondrial (Mit) mutants of Caenorhabditis elegans utilize a novel metabolism

    PubMed Central

    Butler, Jeffrey A.; Ventura, Natascia; Johnson, Thomas E.; Rea, Shane L.

    2010-01-01

    The Caenorhabditis elegans mitochondrial (Mit) mutants have disrupted mitochondrial electron transport chain (ETC) functionality, yet, surprisingly, they are long lived. We have previously proposed that Mit mutants supplement their energy needs by exploiting alternate energy production pathways normally used by wild-type animals only when exposed to hypoxic conditions. We have also proposed that longevity in the Mit mutants arises as a property of their new metabolic state. If longevity does arise as a function of metabolic state, we would expect to find a common metabolic signature among these animals. To test these predictions, we established a novel approach monitoring the C. elegans exometabolism as a surrogate marker for internal metabolic events. Using HPLC-ultraviolet-based metabolomics and multivariate analyses, we show that long-lived clk-1(qm30) and isp-1(qm150) Mit mutants have a common metabolic profile that is distinct from that of aerobically cultured wild-type animals and, unexpectedly, wild-type animals cultured under severe oxygen deprivation. Moreover, we show that 2 short-lived mitochondrial ETC mutants, mev-1(kn1) and ucr-2.3(pk732), also share a common metabolic signature that is unique. We show that removal of soluble fumarate reductase unexpectedly increases health span in several genetically defined Mit mutants, identifying at least 1 alternate energy production pathway, malate dismutation, that is operative in these animals. Our study suggests long-lived, genetically specified Mit mutants employ a novel metabolism and that life span may well arise as a function of metabolic state.—Butler, J. A., Ventura, N., Johnson, T. E., Rea, S. L. Long-lived mitochondrial (Mit) mutants of Caenorhabditis elegans utilize a novel metabolism. PMID:20732954

  4. Knocking down mitochondrial iron transporter (MIT) reprograms primary and secondary metabolism in rice plants.

    PubMed

    Vigani, Gianpiero; Bashir, Khurram; Ishimaru, Yasuhiro; Lehmann, Martin; Casiraghi, Fabio Marco; Nakanishi, Hiromi; Seki, Motoaki; Geigenberger, Peter; Zocchi, Graziano; Nishizawa, Naoko K

    2016-03-01

    Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality. In this work, the metabolic adjustment in the rice (Oryza sativa) mitochondrial Fe transporter knockdown mutant (mit-2) was analysed. Biochemical characterization of purified mitochondria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. Furthermore, some metabolites (e.g. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  5. Knocking down mitochondrial iron transporter (MIT) reprograms primary and secondary metabolism in rice plants

    PubMed Central

    Vigani, Gianpiero; Bashir, Khurram; Ishimaru, Yasuhiro; Lehmann, Martin; Casiraghi, Fabio Marco; Nakanishi, Hiromi; Seki, Motoaki; Geigenberger, Peter; Zocchi, Graziano; Nishizawa, Naoko K.

    2016-01-01

    Iron (Fe) is an essential micronutrient for plant growth and development, and its reduced bioavailability strongly impairs mitochondrial functionality. In this work, the metabolic adjustment in the rice (Oryza sativa) mitochondrial Fe transporter knockdown mutant (mit-2) was analysed. Biochemical characterization of purified mitochondria from rice roots showed alteration in the respiratory chain of mit-2 compared with wild-type (WT) plants. In particular, proteins belonging to the type II alternative NAD(P)H dehydrogenases accumulated strongly in mit-2 plants, indicating that alternative pathways were activated to keep the respiratory chain working. Additionally, large-scale changes in the transcriptome and metabolome were observed in mit-2 rice plants. In particular, a strong alteration (up-/down-regulation) in the expression of genes encoding enzymes of both primary and secondary metabolism was found in mutant plants. This was reflected by changes in the metabolic profiles in both roots and shoots of mit-2 plants. Significant alterations in the levels of amino acids belonging to the aspartic acid-related pathways (aspartic acid, lysine, and threonine in roots, and aspartic acid and ornithine in shoots) were found that are strictly connected to the Krebs cycle. Furthermore, some metabolites (e.g. pyruvic acid, fumaric acid, ornithine, and oligosaccharides of the raffinose family) accumulated only in the shoot of mit-2 plants, indicating possible hypoxic responses. These findings suggest that the induction of local Fe deficiency in the mitochondrial compartment of mit-2 plants differentially affects the transcript as well as the metabolic profiles in root and shoot tissues. PMID:26685186

  6. Enhancements to TauDEM to support Rapid Watershed Delineation Services

    NASA Astrophysics Data System (ADS)

    Sazib, N. S.; Tarboton, D. G.

    2015-12-01

    Watersheds are widely recognized as the basic functional unit for water resources management studies and are important for a variety of problems in hydrology, ecology, and geomorphology. Nevertheless, delineating a watershed spread across a large region is still cumbersome due to the processing burden of working with large Digital Elevation Model. Terrain Analysis Using Digital Elevation Models (TauDEM) software supports the delineation of watersheds and stream networks from within desktop Geographic Information Systems. A rich set of watershed and stream network attributes are computed. However limitations of the TauDEM desktop tools are (1) it supports only one type of raster (tiff format) data (2) requires installation of software for parallel processing, and (3) data have to be in projected coordinate system. This paper presents enhancements to TauDEM that have been developed to extend its generality and support web based watershed delineation services. The enhancements of TauDEM include (1) reading and writing raster data with the open-source geospatial data abstraction library (GDAL) not limited to the tiff data format and (2) support for both geographic and projected coordinates. To support web services for rapid watershed delineation a procedure has been developed for sub setting the domain based on sub-catchments, with preprocessed data prepared for each catchment stored. This allows the watershed delineation to function locally, while extending to the full extent of watersheds using preprocessed information. Additional capabilities of this program includes computation of average watershed properties and geomorphic and channel network variables such as drainage density, shape factor, relief ratio and stream ordering. The updated version of TauDEM increases the practical applicability of it in terms of raster data type, size and coordinate system. The watershed delineation web service functionality is useful for web based software as service deployments

  7. Validation of DEMs Derived from High Resolution SAR Data: a Case Study on Barcelona

    NASA Astrophysics Data System (ADS)

    Sefercik, U. G.; Schunert, A.; Soergel, U.; Watanabe, K.

    2012-07-01

    In recent years, Synthetic Aperture Radar (SAR) data have been widely used for scientific applications and several SAR missions were realized. The active sensor principle and the signal wavelength in the order of centimeters provide all-day and all-weather capabilities, respectively. The modern German TerraSAR-X (TSX) satellite provides high spatial resolution down to one meter. Based on such data SAR Interferometry may yield high quality digital surface models (DSMs), which includes points located on 3d objects such as vegetation, forest, and elevated man-made structures. By removing these points, digital elevation model (DEM) representing the bare ground of Earth is obtained. The primary objective of this paper is the validation of DEMs obtained from TSX SAR data covering Barcelona area, Spain, in the framework of a scientific project conducted by ISPRS Working Group VII/2 "SAR Interferometry" that aims the evaluation of DEM derived from data of modern SAR satellite sensors. Towards this purpose, a DSM was generated with 10 m grid spacing using TSX StripMap mode SAR data and converted to a DEM by filtering. The accuracy results have been presented referring the comparison with a more accurate (10 cm-1 m) digital terrain model (DTM) derived from large scale photogrammetry. The results showed that the TSX DEM is quite coherent with the topography and the accuracy is in between ±8-10 m. As another application, the persistent scatterer interferometry (PSI) was conducted using TSX data and the outcomes were compared with a 3d city model available in Google Earth, which is known to be very precise because it is based on LIDAR data. The results showed that PSI outcomes are quite coherent with reference data and the RMSZ of differences is around 2.5 m.

  8. Inter-agency comparison of TanDEM-X baseline solutions

    NASA Astrophysics Data System (ADS)

    Jäggi, A.; Montenbruck, O.; Moon, Y.; Wermuth, M.; König, R.; Michalak, G.; Bock, H.; Bodenmann, D.

    2012-07-01

    TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurement) is the first Synthetic Aperture Radar (SAR) mission using close formation flying for bistatic SAR interferometry. The primary goal of the mission is to generate a global digital elevation model (DEM) with 2 m height precision and 10 m ground resolution from the configurable SAR interferometer with space baselines of a few hundred meters. As a key mission requirement for the interferometric SAR processing, the relative position, or baseline vector, of the two satellites must be determined with an accuracy of 1 mm (1D RMS) from GPS measurements collected by the onboard receivers. The operational baseline products for the TanDEM-X mission are routinely generated by the German Research Center for Geosciences (GFZ) and the German Space Operations Center (DLR/GSOC) using different software packages (EPOS/BSW, GHOST) and analysis strategies. For a further independent performance assessment, TanDEM-X baseline solutions are generated at the Astronomical Institute of the University of Bern (AIUB) on a best effort basis using the Bernese Software (BSW). Dual-frequency baseline solutions are compared for a 1-month test period in January 2011. Differences of reduced-dynamic baseline solutions exhibit a representative standard deviation (STD) of 1 mm outside maneuver periods, while biases are below 1 mm in all directions. The achieved baseline determination performance is close to the mission specification, but independent SAR calibration data takes acquired over areas with a well known DEM from previous missions will be required to fully meet the 1 mm 1D RMS target. Besides the operational solutions, single-frequency baseline solutions are tested. They benefit from a more robust ambiguity fixing and show a slightly better agreement of below 1 mm STD, but are potentially affected by errors caused by an incomplete compensation of differential ionospheric path delays.

  9. 76 FR 31230 - Safety Zone; M.I.T.'s 150th Birthday Celebration Fireworks, Charles River, Boston, MA

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-31

    ... SECURITY Coast Guard 33 CFR Part 165 RIN 1625-AA00 Safety Zone; M.I.T.'s 150th Birthday Celebration...) Zone for the M.I.T.'s 150th Birthday Celebration Fireworks display. This safety zone is necessary to.... 165.T01-0375 to read as follows: Sec. 165.T01-0375 Safety Zone; M.I.T.'s 150th Birthday...

  10. Mit1 Transcription Factor Mediates Methanol Signaling and Regulates the Alcohol Oxidase 1 (AOX1) Promoter in Pichia pastoris.

    PubMed

    Wang, Xiaolong; Wang, Qi; Wang, Jinjia; Bai, Peng; Shi, Lei; Shen, Wei; Zhou, Mian; Zhou, Xiangshan; Zhang, Yuanxing; Cai, Menghao

    2016-03-18

    The alcohol oxidase 1 (AOX1) promoter (P AOX1) of Pichia pastoris is the most powerful and commonly used promoter for driving protein expression. However, mechanisms regulating its transcriptional activity are unclear. Here, we identified a Zn(II)2Cys6-type methanol-induced transcription factor 1 (Mit1) and elucidated its roles in regulating PAOX1 activity in response to glycerol and methanol. Mit1 regulated the expression of many genes involved in methanol utilization pathway, including AOX1, but did not participate in peroxisome proliferation and transportation of peroxisomal proteins during methanol metabolism. Structural analysis of Mit1 by performing domain deletions confirmed its specific and critical role in the strict repression of P AOX1 in glycerol medium. Importantly, Mit1, Mxr1, and Prm1, which positively regulated P AOX1 in response to methanol, were bound to P AOX1 at different sites and did not interact with each other. However, these factors cooperatively activated P AOX1 through a cascade. Mxr1 mainly functioned during carbon derepression, whereas Mit1 and Prm1 functioned during methanol induction, with Prm1 transmitting methanol signal to Mit1 by binding to the MIT1 promoter (P MIT1), thus increasingly expressing Mit1 and subsequently activating P AOX1.

  11. Detailed geomorphological mapping from high resolution DEM data (LiDAR, TanDEM-X): two case studies from Germany and SE Tibet

    NASA Astrophysics Data System (ADS)

    Loibl, D.

    2012-04-01

    Two major obstacles are hampering the production of high resolution geomorphological maps: the complexity of the subject that should be depicted and the enormous efforts necessary to obtain data by field work. The first factor prevented the establishment of a generally accepted map legend; the second hampered efforts to collect comprehensive sets of geomorphological data. This left geomorphologists to produce applied maps, focusing on very few layers of information and often not sticking to any of the numerous standards proposed in the second half of the 20th century. Technological progress of the recent years, especially in the fields of digital elevation models, GIS environments, and computational hardware, today offers promising opportunities to overcome the obstacles and to produce detailed geomorphological maps even for remote or inhospitable regions. The feasibility of detailed geomorphological mapping from two new sets of digital elevation data, the 1 m LiDAR DTM provided by Germany's State Surveying Authority and the upcoming TanDEM-X DEM, has been evaluated in two case studies from a low mountain range in Germany and a high mountain range in SE Tibet. The results indicate that most layers of information of classical geomorphological maps (e.g. the German GMK) can be extracted from this data at appropriate scales but that significant differences occur concerning the quality and the grades of certainty of key contents. Generally, an enhancement of the geomorphographical, especially the geomorphometrical, and a weakening of geomorphogenetical contents was observed. From these findings, theoretical, methodological, and cartographical remarks on detailed geomorphological mapping from DEM data in GIS environments were educed. As GIS environments decouple data and design and enable the geomorphologist to choose information layer combinations freely to fit research topics, a general purpose legend becomes obsolete. Yet, a unified data structure is demanded to

  12. Generation of a precise DEM by interactive synthesis of multi-temporal elevation datasets: a case study of Schirmacher Oasis, East Antarctica

    NASA Astrophysics Data System (ADS)

    Jawak, Shridhar D.; Luis, Alvarinho J.

    2016-05-01

    Digital elevation model (DEM) is indispensable for analysis such as topographic feature extraction, ice sheet melting, slope stability analysis, landscape analysis and so on. Such analysis requires a highly accurate DEM. Available DEMs of Antarctic region compiled by using radar altimetry and the Antarctic digital database indicate elevation variations of up to hundreds of meters, which necessitates the generation of local improved DEM. An improved DEM of the Schirmacher Oasis, East Antarctica has been generated by synergistically fusing satellite-derived laser altimetry data from Geoscience Laser Altimetry System (GLAS), Radarsat Antarctic Mapping Project (RAMP) elevation data and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) global elevation data (GDEM). This is a characteristic attempt to generate a DEM of any part of Antarctica by fusing multiple elevation datasets, which is essential to model the ice elevation change and address the ice mass balance. We analyzed a suite of interpolation techniques for constructing a DEM from GLAS, RAMP and ASTER DEM-based point elevation datasets, in order to determine the level of confidence with which the interpolation techniques can generate a better interpolated continuous surface, and eventually improve the elevation accuracy of DEM from synergistically fused RAMP, GLAS and ASTER point elevation datasets. The DEM presented in this work has a vertical accuracy (≈ 23 m) better than RAMP DEM (≈ 57 m) and ASTER DEM (≈ 64 m) individually. The RAMP DEM and ASTER DEM elevations were corrected using differential GPS elevations as ground reference data, and the accuracy obtained after fusing multitemporal datasets is found to be improved than that of existing DEMs constructed by using RAMP or ASTER alone. This is our second attempt of fusing multitemporal, multisensory and multisource elevation data to generate a DEM of Antarctica, in order to address the ice elevation change and address the ice mass

  13. The knockdown of OsVIT2 and MIT affects iron localization in rice seed.

    PubMed

    Bashir, Khurram; Takahashi, Ryuichi; Akhtar, Shamim; Ishimaru, Yasuhiro; Nakanishi, Hiromi; Nishizawa, Naoko K

    2013-11-20

    The mechanism of iron (Fe) uptake in plants has been extensively characterized, but little is known about how Fe transport to different subcellular compartments affects Fe localization in rice seed. Here, we discuss the characterization of a rice vacuolar Fe transporter 2 (OsVIT2) T-DNA insertion line (osvit2) and report that the knockdown of OsVIT2 and mitochondrial Fe transporter (MIT) expression affects seed Fe localization. osvit2 plants accumulated less Fe in their shoots when grown under normal or excess Fe conditions, while the accumulation of Fe was comparable to that in wild-type (WT) plants under Fe-deficient conditions. The accumulation of zinc, copper, and manganese also changed significantly in the shoots of osvit2 plants. The growth of osvit2 plants was also slow compared to that of WT plants. The concentration of Fe increased in osvit2 polished seeds. Previously, we reported that the expression of OsVIT2 was higher in MIT knockdown (mit-2) plants, and in this study, the accumulation of Fe in mit-2 seeds decreased significantly. These results suggest that vacuolar Fe trafficking is important for plant Fe homeostasis and distribution, especially in plants grown in the presence of excess Fe. Moreover, changes in the expression of OsVIT2 and MIT affect the concentration and localization of metals in brown rice as well as in polished rice seeds.

  14. Designs of LiMIT as a Limiter in the EAST Tokamak

    NASA Astrophysics Data System (ADS)

    Szott, Matthew; Christenson, Michael; Kalathiparambil, Kishor; Ruzic, David

    2016-10-01

    Liquid metal plasma facing components (PFCs) provide a constantly refreshing, self-healing surface that can reduce erosion and thermal stress damage to prolong device lifetime, and additionally decrease edge recycling, reduce impurities, and enhance plasma performance. The Liquid Metal Infused Trench (LiMIT) system, developed at UIUC, has demonstrated thermoelectric magnetohydrodynamic (TEMHD) driven flow of liquid lithium through series of solid trenches. This TEMHD effect drives liquid lithium in fusion systems using the plasma heat flux and the toroidal magnetic field, and the surface tension of the liquid lithium maintains a fresh surface on top of the solid trenches. LiMIT has been successfully tested at UIUC as well as HT-7 and Magnum PSI at heat fluxes up to 3 MW/m2. The next step is demonstrating system viability in full-scale fusion-relevant conditions. In collaboration with a team in Hefei, design and testing has begun for a large scale LiMIT system that will act as a limiter in EAST. The designs improve upon previous versions of LiMIT tested at Illinois and incorporate lessons learned from earlier tests of liquid metal PFCs at EAST. Existing infrastructure is used to load and supply lithium to the system, and the LiMIT trenches will help maintain a smooth, fresh surface as well as aid in propelling the lithium out of direct plasma flux to improve heat transfer. Supported by DOE/ALPS DE-FG02-99ER54515.

  15. Effects of DEM scale on the spatial distribution of the TOPMODEL topographic wetness index and its correlations to watershed characteristics

    NASA Astrophysics Data System (ADS)

    Drover, D. R.; Jackson, C. R.; Bitew, M.; Du, E.

    2015-11-01

    Topographic wetness indices (TWIs) calculated from digital elevation models (DEMs) are meant to predict relative landscape wetness and should have predictive power for soil and vegetation attributes. While previous researchers have shown cumulative TWI distributions shift to larger values as DEM resolution decreases, there has been little work assessing how DEM scales affect TWI spatial distributions and correlations with soil and vegetation properties. We explored how various DEM resolutions (2, 5, 10, 20, 30, and 50 m) subsampled from high definition LiDAR altered the spatial distribution of TWI values and the correlations of these values with soil characteristics determined from point samples, Natural Resources Conservation Service (NRCS) soil units, depths to groundwater, and managed vegetation distributions within a first order basin in the Upper Southeastern Coastal Plain with moderate slopes, flat valleys, and several wetlands. Point-scale soil characteristics were determined by laboratory analysis of point samples collected from riparian transects and hillslope grids. DEM scale affected the spatial distribution of TWI values in ways that affect our interpretation of landscape processes. At the finest DEM resolutions, valleys disappeared as TWI values were driven by local microtopography and not basin position. Spatial distribution of TWI values most closely matched the spatial distribution of soils, depth to groundwater, and vegetation stands for the 10, 20, and 30 m resolutions. DEM resolution affected the shape and direction of relationships between soil nitrogen and carbon contents and TWI values, but TWI values provided poor prediction of soil chemistry at all resolutions.

  16. A global vegetation corrected SRTM DEM for use in hazard modelling

    NASA Astrophysics Data System (ADS)

    Bates, P. D.; O'Loughlin, F.; Neal, J. C.; Durand, M. T.; Alsdorf, D. E.; Paiva, R. C. D.

    2015-12-01

    We present the methodology and results from the development of a near-global 'bare-earth' Digital Elevation Model (DEM) derived from the Shuttle Radar Topography Mission (SRTM) data. Digital Elevation Models are the most important input for hazard modelling, as the DEM quality governs the accuracy of the model outputs. While SRTM is currently the best near-globally [60N to 60S] available DEM, it requires adjustments to reduce the vegetation contamination and make it useful for hazard modelling over heavily vegetated areas (e.g. tropical wetlands). Unlike previous methods of accounting for vegetation contamination, which concentrated on correcting relatively small areas and usually applied a static adjustment, we account for vegetation contamination globally and apply a spatial varying correction, based on information about canopy height and density. Our new 'Bare-Earth' SRTM DEM combines multiple remote sensing datasets, including ICESat GLA14 ground elevations, the vegetation continuous field dataset as a proxy for penetration depth of SRTM and a global vegetation height map, to remove the vegetation artefacts present in the original SRTM DEM. In creating the final 'bare-earth' SRTM DEM dataset, we produced three different 'bare-earth' SRTM products. The first applies global parameters, while the second and third products apply parameters that are regionalised based on either climatic zones or vegetation types, respectively. We also tested two different canopy density proxies of different spatial resolution. Using ground elevations obtained from the ICESat GLA14 satellite altimeter, we calculate the residual errors for the raw SRTM and the three 'bare-earth' SRTM products and compare performances. The three 'bare-earth' products all show large improvements over the raw SRTM in vegetated areas with the overall mean bias reduced by between 75 and 92% from 4.94 m to 0.40 m. The overall standard deviation is reduced by between 29 and 33 % from 7.12 m to 4.80 m. As

  17. Methodologies for watershed modeling with GIS and DEMs for the parameterization of the WEPP model

    NASA Astrophysics Data System (ADS)

    Cochrane, Thomas Arey

    Two methods called the Hillslope and Flowpath methods were developed that use geographical information systems (GIS) and digital elevation models (DEMs) to assess water erosion in small watersheds with the Water Erosion Prediction Project (WEPP) model. The Hillslope method is an automated method for the application of WEPP through the extraction of hillslopes and channels from DEMs. Each hillslope is represented as a rectangular area with a representative slope profile that drains to the top or sides of a single channel. The Hillslope method was further divided into the Calcleng and Chanleng methods, which are similar in every way except on how the hillslope lengths are calculated. The Calcleng method calculates a representative length of hillslope based on the weighted lengths of all flowpaths in a hillslope as identified through a DEM. The Chanleng method calculates the length of hillslopes adjacent to channels by matching the width of the hillslope to the length of adjacent channel. The Flowpath method works by applying the WEPP model to all possible flowpaths within a watershed as identified from a DEM. However, this method does not currently have a channel routing component, which limits its use to predicting spatially variable erosion on hillslopes within the watershed or from watersheds whose channels are not in a depositional or erodible mode. These methods were evaluated with six research watersheds from across the U.S., one from Treynor, Iowa, two from Watkinsville, Georgia, and three from Holly Springs, Mississippi. The effects of using different-sized DEM resolutions on simulations and the ability to accurately predict sediment yield and runoff from different event sizes were studied. Statistical analyses for all methods, resolutions, and event sizes were performed by comparing predicted vs. measured runoff and sediment yield from the watershed outlets on an event by event basis. Comparisons to manual applications by expert users and comparisons of

  18. Visualising DEM-related flood-map uncertainties using a disparity-distance equation algorithm

    NASA Astrophysics Data System (ADS)

    Brandt, S. Anders; Lim, Nancy J.

    2016-05-01

    The apparent absoluteness of information presented by crisp-delineated flood boundaries can lead to misconceptions among planners about the inherent uncertainties associated in generated flood maps. Even maps based on hydraulic modelling using the highest-resolution digital elevation models (DEMs), and calibrated with the most optimal Manning's roughness (n) coefficients, are susceptible to errors when compared to actual flood boundaries, specifically in flat areas. Therefore, the inaccuracies in inundation extents, brought about by the characteristics of the slope perpendicular to the flow direction of the river, have to be accounted for. Instead of using the typical Monte Carlo simulation and probabilistic methods for uncertainty quantification, an empirical-based disparity-distance equation that considers the effects of both the DEM resolution and slope was used to create prediction-uncertainty zones around the resulting inundation extents of a one-dimensional (1-D) hydraulic model. The equation was originally derived for the Eskilstuna River where flood maps, based on DEM data of different resolutions, were evaluated for the slope-disparity relationship. To assess whether the equation is applicable to another river with different characteristics, modelled inundation extents from the Testebo River were utilised and tested with the equation. By using the cross-sectional locations, water surface elevations, and DEM, uncertainty zones around the original inundation boundary line can be produced for different confidences. The results show that (1) the proposed method is useful both for estimating and directly visualising model inaccuracies caused by the combined effects of slope and DEM resolution, and (2) the DEM-related uncertainties alone do not account for the total inaccuracy of the derived flood map. Decision-makers can apply it to already existing flood maps, thereby recapitulating and re-analysing the inundation boundaries and the areas that are uncertain

  19. MIT Clean Energy Prize: Final Technical Report May 12, 2010 - May 11, 2011

    SciTech Connect

    Snyder, Chris; Campbell, Georgina; Salony, Jason; Aulet, Bill

    2011-08-09

    The MIT Clean Energy Prize (MIT CEP) is a venture creation and innovation competition to encourage innovation in the energy space, specifically with regard to clean energy. The Competition invited student teams from any US university to submit student-led ventures that demonstrate a high potential of successfully making clean energy more affordable, with a positive impact on the environment. By focusing on student ventures, the MIT CEP aims to educate the next generation of clean energy entrepreneurs. Teams receive valuable mentoring and hard deadlines that complement the cash prize to accelerate development of ventures. The competition is a year-long educational process that culminates in the selection of five category finalists and a Grand Prize winner and the distribution of cash prizes to each of those teams. Each entry was submitted in one of five clean energy categories: Renewables, Clean Non-Renewables, Energy Efficiency, Transportation, and Deployment.

  20. MITR-III: Upgrade and relicensing studies for the MIT Research Reactor. Second annual report

    SciTech Connect

    Trosman, H.G.; Lanning, D.D.; Harling, O.K.

    1994-08-01

    The current operating license of the MIT research reactor will expire on May 7, 1996 or possibly a few years later if the US Nuclear Regulatory Commission agrees that the license period can start with the date of initial reactor operation. Driven by the imminent expiration of the operating license, a team of nuclear engineering staff and students have begun a study of the future options for the MIT Research Reactor. These options have included the range from a major rebuilding of the reactor to its decommissioning. This document reports the results of a two year intensive activity which has been supported by a $148,000 grant from the USDOE contract Number DEFG0293ER75859, approximately $100,000 of internal MIT funds and Nuclear Engineering Department graduate student fellowships as well as assistance from international visiting scientists and engineers.

  1. A New Tool for Inundation Modeling: Community Modeling Interface for Tsunamis (ComMIT)

    NASA Astrophysics Data System (ADS)

    Titov, V. V.; Moore, C. W.; Greenslade, D. J. M.; Pattiaratchi, C.; Badal, R.; Synolakis, C. E.; Kânoğlu, U.

    2011-11-01

    Almost 5 years after the 26 December 2004 Indian Ocean tragedy, the 10 August 2009 Andaman tsunami demonstrated that accurate forecasting is possible using the tsunami community modeling tool Community Model Interface for Tsunamis (ComMIT). ComMIT is designed for ease of use, and allows dissemination of results to the community while addressing concerns associated with proprietary issues of bathymetry and topography. It uses initial conditions from a precomputed propagation database, has an easy-to-interpret graphical interface, and requires only portable hardware. ComMIT was initially developed for Indian Ocean countries with support from the United Nations Educational, Scientific, and Cultural Organization (UNESCO), the United States Agency for International Development (USAID), and the National Oceanic and Atmospheric Administration (NOAA). To date, more than 60 scientists from 17 countries in the Indian Ocean have been trained and are using it in operational inundation mapping.

  2. Fusion Science Outreach at the MIT Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.; Rivenberg, P.; Granville, J.; Nachtrieb, R.; Gangadhara, S.

    1997-11-01

    Educational Outreach at the MIT Plasma Science and Fusion Center is organized and energized by volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. The PSFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Included in these days is a demonstration of how magnets affect plasma using the ``Plasma Demo," an educational tool which will be on display for the first time outside the MIT area. Also featured is ``C-Mod Jr.," a video game which helps students discover how computers manipulate magnetic pulses to keep a plasma confined in the C-Mod tokamak for as long as possible. The PSFC maintains a Home Page on the World Wide Web, which can be reached at HTTP://PFC.MIT.EDU.

  3. Education Outreach at M.I.T. Plasma Science and Fusion Center

    NASA Astrophysics Data System (ADS)

    Rivenberg, P.; Censabella, V.

    2000-10-01

    At the MIT PSFC student and staff volunteers work together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PSFC holds a number of outreach activities throughout the year, including Middle and High School Outreach Days and the Mr. Magnet program. During the past year, in collaboration with the MIT Museum, the PSFC reprogrammed their C-Mod, Jr Video Game to be operated via the keyboard instead of joysticks. The game will eventually be available on the web and on disc. The PSFC maintains a Home Page on the World Wide Web, which can be reached at http://www.psfc.mit.edu.

  4. Long-lived mitochondrial (Mit) mutants of Caenorhabditis elegans utilize a novel metabolism.

    PubMed

    Butler, Jeffrey A; Ventura, Natascia; Johnson, Thomas E; Rea, Shane L

    2010-12-01

    The Caenorhabditis elegans mitochondrial (Mit) mutants have disrupted mitochondrial electron transport chain (ETC) functionality, yet, surprisingly, they are long lived. We have previously proposed that Mit mutants supplement their energy needs by exploiting alternate energy production pathways normally used by wild-type animals only when exposed to hypoxic conditions. We have also proposed that longevity in the Mit mutants arises as a property of their new metabolic state. If longevity does arise as a function of metabolic state, we would expect to find a common metabolic signature among these animals. To test these predictions, we established a novel approach monitoring the C. elegans exometabolism as a surrogate marker for internal metabolic events. Using HPLC-ultraviolet-based metabolomics and multivariate analyses, we show that long-lived clk-1(qm30) and isp-1(qm150) Mit mutants have a common metabolic profile that is distinct from that of aerobically cultured wild-type animals and, unexpectedly, wild-type animals cultured under severe oxygen deprivation. Moreover, we show that 2 short-lived mitochondrial ETC mutants, mev-1(kn1) and ucr-2.3(pk732), also share a common metabolic signature that is unique. We show that removal of soluble fumarate reductase unexpectedly increases health span in several genetically defined Mit mutants, identifying at least 1 alternate energy production pathway, malate dismutation, that is operative in these animals. Our study suggests long-lived, genetically specified Mit mutants employ a novel metabolism and that life span may well arise as a function of metabolic state.

  5. Center for Multiscale Plasma Dynamics: Report on Activities (UCLA/MIT), 2009-2010

    SciTech Connect

    Troy Carter

    2011-04-18

    The final 'phaseout' year of the CMPD ended July 2010; a no cost extension was requested until May 2011 in order to enable the MIT subcontract funds to be fully utilized. Research progress over this time included verification and validation activities for the BOUT and BOUT++ code, studies of spontaneous reconnection in the VTF facility at MIT, and studies of the interaction between Alfven waves and drift waves in LAPD. The CMPD also hosted the 6th plasma physics winter school in 2010 (jointly with the NSF frontier center the Center for Magnetic Self-Organization, significant funding came from NSF for this most recent iteration of the Winter School).

  6. Micromechanics of non-active clays in saturated state and DEM modelling

    NASA Astrophysics Data System (ADS)

    Pagano, Arianna Gea; Tarantino, Alessandro; Pedrotti, Matteo; Magnanimo, Vanessa; Windows-Yule, Kit; Weinhart, Thomas

    2017-06-01

    The paper presents a conceptual micromechanical model for 1-D compression behaviour of non-active clays in saturated state. An experimental investigation was carried out on kaolin clay samples saturated with fluids of different pH and dielectric permittivity. The effect of pore fluid characteristics on one-dimensional compressibility behaviour of kaolin was investigated. A three dimensional Discrete Element Method (DEM) was implemented in order to simulate the response of saturated kaolin observed during the experiments. A complex contact model was introduced, considering both the mechanical and physico-chemical microscopic interactions between clay particles. A simple analysis with spherical particles only was performed as a preliminary step in the DEM study in the elastic regime.

  7. A hybrid FEM-DEM approach to the simulation of fluid flow laden with many particles

    NASA Astrophysics Data System (ADS)

    Casagrande, Marcus V. S.; Alves, José L. D.; Silva, Carlos E.; Alves, Fábio T.; Elias, Renato N.; Coutinho, Alvaro L. G. A.

    2017-04-01

    In this work we address a contribution to the study of particle laden fluid flows in scales smaller than TFM (two-fluid models). The hybrid model is based on a Lagrangian-Eulerian approach. A Lagrangian description is used for the particle system employing the discrete element method (DEM), while a fixed Eulerian mesh is used for the fluid phase modeled by the finite element method (FEM). The resulting coupled DEM-FEM model is integrated in time with a subcycling scheme. The aforementioned scheme is applied in the simulation of a seabed current to analyze which mechanisms lead to the emergence of bedload transport and sediment suspension, and also quantify the effective viscosity of the seabed in comparison with the ideal no-slip wall condition. A simulation of a salt plume falling in a fluid column is performed, comparing the main characteristics of the system with an experiment.

  8. Coupled DEM-CFD Investigation of Granular Transport in a Fluid Channel

    NASA Astrophysics Data System (ADS)

    Zhao, T.; Dai, F.; Xu, N. W.

    2015-09-01

    This paper presents three dimensional numerical investigations of granular transport in fluids, analysed by the Discrete Element Method (DEM) coupled with Computational Fluid Mechanics (CFD). By employing this model, the relevance of flow velocity and granular depositional morphology has been clarified. The larger the flow velocity is, the further distance the grains can be transported to. In this process, the segregation of solid grains has been clearly identified. This research reveals that coarse grains normally accumulate near the grain source region, while the fine grains can be transported to the flow front. Regardless of the different flow velocities used in these simulations, the intensity of grains segregation remains almost unchanged. The results obtained from the DEM-CFD coupled simulations can reasonably explain the grain transport process occurred in natural environments, such as river scouring, evolution of river/ocean floor, deserts and submarine landslides.

  9. Análisis DEM 3D de arcos en regiones activas solares

    NASA Astrophysics Data System (ADS)

    Nuevo, F. A.; Mandrini, C. H.; Vásquez, A. M.; López Fuentes, M.

    2016-08-01

    The solar corona is highly organized by the magnetic field. Because of their temperature and density, magnetic loops are directly observable in active regions (ARs) in the extreme ultraviolet (EUV) and soft X-ray images. The observational determination of the three-dimensional (3D) distribution of basic physical parameters (electronic density and temperature, and magnetic field) is a fundamental constraint of coronal heating models. In this work we develop a technique of differential emission measure (DEM) analysis and we apply it an EUV loop identified in the images of the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The DEM is determined after background subtraction and the electronic density and temperature in the loop are estimated from its moments. The 3D structure of the magnetic field in the loop and its intensity are modeled using linear force free field extrapolations based on AR magnetograms. In this work we show preliminary results of this technique.

  10. A comparison between DEM and MPM for the modeling of unsteady flow

    NASA Astrophysics Data System (ADS)

    Gracia, Fabio; Villard, Pascal; Richefeu, Vincent

    2017-06-01

    In order to provide a comprehensive comparison between two current numerical methods employed in the modeling of rock avalanches, the Discrete Element Method (DEM) [3] and the Material Point Method (MPM) [1] were used to simulate the mass propagation along a 45° plane transitioning to an horizontal plane. When using the DEM, a 3D code using tetrahedral elements was used and the flow was channelized by means of frictionless walls. For the MPM simulations, a 2D code was developed and plane strain simulations were run. Comparisons were made in terms of run-out distance and energy dissipated. Influence of parameters such as initial sample geometry, basal friction coefficient and shape of blocks composing the sample was studied.

  11. Simulation of Roasting Metallurgical Concentrates in Fluidized Bed Using CFD-DEM

    NASA Astrophysics Data System (ADS)

    Beloglazov, I. I.; Kuskova, Y. V.

    2017-07-01

    In this study, we utilized multiphase computational fluid dynamics (CFD), and discrete element method (DEM). Effect of the kinetic parameters of the roasting process in a fluidized bed was investigated. Our results indicate that it is possible to numerically integrate the coupled CFD-DEM system without significantly increasing computational overhead. It is also clear, however, that reactor operating conditions, reaction kinetics, and multiphase flow dynamics have major impacts on the roasting products exiting the reactor. We find that, with the same pre-exponential factors and mean activation energies, inclusion of distributed activation energies in the kinetics can shift the predicted average value of the exit gas-solidphase and its statistical distribution, compared to single-valued activation-energy kinetics. These findings imply that accurate resolution of the reaction activation energy distributions will be important for optimizing roasting processes.

  12. DEM extraction and its accuracy analysis with ground-based SAR interferometry

    NASA Astrophysics Data System (ADS)

    Dong, J.; Yue, J. P.; Li, L. H.

    2014-03-01

    Two altimetry models extracting DEM (Digital Elevation Model) with the GBSAR (Ground-Based Synthetic Aperture Radar) technology are studied and their accuracies are analyzed in detail. The approximate and improved altimetry models of GBSAR were derived from the spaceborne radar altimetry based on the principles of the GBSAR technology. The error caused by the parallel ray approximation in the approximate model was analyzed quantitatively, and the results show that the errors cannot be ignored for the ground-based radar system. For the improved altimetry model, the elevation error expression can be acquired by simulating and analyzing the error propagation coefficients of baseline length, wavelength, differential phase and range distance in the mathematical model. By analyzing the elevation error with the baseline and range distance, the results show that the improved altimetry model is suitable for high-precision DEM and the accuracy can be improved by adjusting baseline and shortening slant distance.

  13. Implementing a global DEM database on the sphere based on spherical wavelets

    NASA Astrophysics Data System (ADS)

    Zhao, Di; Zhao, Xuesheng; Shan, Shigang; Yao, Liangjun

    2010-11-01

    Wavelets have been proven to be an exceedingly powerful and highly efficient tool for fast computational algorithms in the fields of image data analysis and compression. Traditionally, the classical constructed wavelets are often employed to Euclidean infinite domains (such as the real line R and plane R2). In this paper, a spherical wavelet constructed for discrete DEM data based on the sphere is approached. Firstly, the discrete biorthogonal spherical wavelet with custom properties is constructed with the lifting scheme based on wavelet toolbox in Matlab. Then, the decomposition and reconstruction algorithms are proposed for efficient computation and the related wavelet coefficients are obtained. Finally, different precise images are displayed and analyzed at the different percentage of wavelet coefficients. The efficiency of this spherical wavelet algorithm is tested by using the GTOPO30 DEM data and the results show that at the same precision, the spherical wavelet algorithm consumes smaller storage volume. The results are good and acceptable.

  14. Implementing a global DEM database on the sphere based on spherical wavelets

    NASA Astrophysics Data System (ADS)

    Zhao, Di; Zhao, Xuesheng; Shan, Shigang; Yao, Liangjun

    2009-09-01

    Wavelets have been proven to be an exceedingly powerful and highly efficient tool for fast computational algorithms in the fields of image data analysis and compression. Traditionally, the classical constructed wavelets are often employed to Euclidean infinite domains (such as the real line R and plane R2). In this paper, a spherical wavelet constructed for discrete DEM data based on the sphere is approached. Firstly, the discrete biorthogonal spherical wavelet with custom properties is constructed with the lifting scheme based on wavelet toolbox in Matlab. Then, the decomposition and reconstruction algorithms are proposed for efficient computation and the related wavelet coefficients are obtained. Finally, different precise images are displayed and analyzed at the different percentage of wavelet coefficients. The efficiency of this spherical wavelet algorithm is tested by using the GTOPO30 DEM data and the results show that at the same precision, the spherical wavelet algorithm consumes smaller storage volume. The results are good and acceptable.

  15. The slowly varying corona from DEMs with the EVE data set

    NASA Astrophysics Data System (ADS)

    Schonfeld, Samuel J.; White, Stephen M.; Hock, Rachel A.; McAteer, James

    2016-05-01

    We present a differential emission measure (DEM) analysis of the slowly varying corona during the first half of solar cycle 24. Using the Extreme ultraviolet Variability Experiment (EVE) and the CHIANTI atomic line database we identify strong isolated iron emission lines present in the non-flaring spectrum with peak emissions covering the coronal temperature range of 5.7 < log(T) < 6.5. These lines are used to generate daily DEMs from EVE spectra to observe the long term variability of global coronal thermal properties. We discuss the choice of emission lines and the implications of this data set for the relationship between EUV and the F10.7 radio flux.

  16. Quasistatic behaviour of granular materials: Some things we learned from DEM studies

    NASA Astrophysics Data System (ADS)

    Roux, Jean-Noël

    2013-06-01

    We propose a quick overview of some aspects of granular quasistatic rheophysics that are being better understood thanks to the micromechanical viewpoint enabled by grain-level discrete element simulations (DEM): the random close packing state of maximally dense disordered assemblies, the approach to the "critical state" of continuously sheared materials, the role of elasticity and contact deformability in macroscopic strains, the nature of the quasistatic limit of slow deformation.

  17. Development of DEM formalism to modeling the dynamic response of brittle solids

    NASA Astrophysics Data System (ADS)

    Grigoriev, Aleksandr S.; Shilko, Eugeny V.; Psakhie, Sergey G.

    2016-11-01

    The paper presents a numerical model of the response for brittle materials to dynamic mechanical loading and implementation of the model within the discrete element method (DEM) by the example of the movable cellular automaton method (MCA). Verification of the model was carried out using the numerical modeling of the uniaxial compression tests of concrete and sandstone samples at various strain rates. It is shown that the developed model is correct and adequately describes the behavior of brittle materials under dynamic loading.

  18. Aster Global dem Version 3, and New Aster Water Body Dataset

    NASA Astrophysics Data System (ADS)

    Abrams, M.

    2016-06-01

    In 2016, the US/Japan ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) project released Version 3 of the Global DEM (GDEM). This 30 m DEM covers the earth's surface from 82N to 82S, and improves on two earlier versions by correcting some artefacts and filling in areas of missing DEMs by the acquisition of additional data. The GDEM was produced by stereocorrelation of 2 million ASTER scenes and operation on a pixel-by-pixel basis: cloud screening; stacking data from overlapping scenes; removing outlier values, and averaging elevation values. As previously, the GDEM is packaged in ~ 23,000 1 x 1 degree tiles. Each tile has a DEM file, and a NUM file reporting the number of scenes used for each pixel, and identifying the source for fill-in data (where persistent clouds prevented computation of an elevation value). An additional data set was concurrently produced and released: the ASTER Water Body Dataset (AWBD). This is a 30 m raster product, which encodes every pixel as either lake, river, or ocean; thus providing a global inland and shore-line water body mask. Water was identified through spectral analysis algorithms and manual editing. This product was evaluated against the Shuttle Water Body Dataset (SWBD), and the Landsat-based Global Inland Water (GIW) product. The SWBD only covers the earth between about 60 degrees north and south, so it is not a global product. The GIW only delineates inland water bodies, and does not deal with ocean coastlines. All products are at 30 m postings.

  19. A 'Drift' algorithm for integrating vector polyline and DEM based on the spherical DQG

    NASA Astrophysics Data System (ADS)

    Wang, Jiaojiao; Wang, Lei; Cao, Wenmin; Zhao, Xuesheng

    2014-03-01

    The efficient integration method of vector and DEM data on a global scale is one of the important issues in the community of Digital Earth. Among the existing methods, geometry-based approach maintains the characteristics of vector data necessary for inquiry and analysis. However, the complexity of geometry-based approach, which needs lots of interpolation calculation, limits its applications greatly in the multi-source spatial data integration on a global scale. To overcome this serious deficiency, a novel 'drift' algorithm is developed based on the spherical Degenerate Quadtree Grid (DQG) on which the global DEMs data is represented. The main principle of this algorithm is that the vector node in a DQG cell can be moved to the cell corner-point without changing the visualization effects if the cell is smaller or equal to a pixel of screen. A detailed algorithm and the multi-scale operation steps are also presented. By the 'drift' algorithm, the vector polylines and DEM grids are integrated seamlessly, avoiding lots of interpolation calculating. Based on the approach described above, we have developed a computer program in platform OpenGL 3D API with VC++ language. In this experiment, USGS GTOPO30 DEM data and 1:1,000,000 DCW roads data sets in China area are selected. Tests have shown that time consumption of the 'drift' algorithm is only about 25% of that of the traditional ones, moreover, the mean error of drift operation on vector nodes can be controlled within about half a DQG cell. In the end, the conclusions and future works are also given.

  20. A time series of TanDEM-X digital elevation models to monitor a glacier surge

    NASA Astrophysics Data System (ADS)

    Wendt, Anja; Mayer, Christoph; Lambrecht, Astrid; Floricioiu, Dana

    2016-04-01

    Bivachny Glacier, a tributary of the more than 70 km long Fedchenko Glacier in the Pamir Mountains, Central Asia, is a surge-type glacier with three known surges during the 20th century. In 2011, the most recent surge started which, in contrast to the previous ones, evolved down the whole glacier and reached the confluence with Fedchenko Glacier. Spatial and temporal glacier volume changes can be derived from high-resolution digital elevation models (DEMs) based on bistatic InSAR data from the TanDEM-X mission. There are nine DEMs available between 2011 and 2015 covering the entire surge period in time steps from few months up to one year. During the surge, the glacier surface elevation increased by up to 130 m in the lower part of the glacier; and change rates of up to 0.6 m per day were observed. The surface height dataset was complemented with glacier surface velocity information from TerraSAR-X/ TanDEM-X data as well as optical Landsat imagery. While the glacier was practically stagnant in 2000 after the end of the previous surge in the 1990s, the velocity increase started in 2011 in the upper reaches of the ablation area and successively moved downwards and intensified, reaching up to 4.0 m per day. The combination of surface elevation changes and glacier velocities, both of high temporal and spatial resolution, provides the unique opportunity to describe and analyse the evolution of the surge in unprecedented detail. Especially the relation between the mobilization front and the local mass transport provides insight into the surge dynamics.

  1. High resolution DEM from Tandem-X interferometry: an accurate tool to characterize volcanic activity

    NASA Astrophysics Data System (ADS)

    Albino, Fabien; Kervyn, Francois

    2013-04-01

    Tandem-X mission was launched by the German agency (DLR) in June 2010. It is a new generation high resolution SAR sensor mainly dedicated to topographic applications. For the purpose of our researches focused on the study of the volcano-tectonic activity in the Kivu Rift area, a set of Tandem-X bistatic radar images were used to produce a high resolution InSAR DEM of the Virunga Volcanic Province (VVP). The VVP is part of the Western branch of the African rift, situated at the boundary between D.R. Congo, Rwanda and Uganda. It has two highly active volcanoes, Nyiragongo and Nyamulagira. A first task concerns the quantitative assessment of the vertical accuracy that can be achieved with these new data. The new DEMs are compared to other space borne datasets (SRTM, ASTER) but also to field measurements given by differential GPS. Multi-temporal radar acquisitions allow us to produce several DEM of the same area. This appeared to be very useful in the context of an active volcanic context where new geomorphological features (faults, fissures, volcanic cones and lava flows) appear continuously through time. For example, since the year 2000, time of the SRTM acquisition, we had one eruption at Nyiragongo (2002) and six eruptions at Nyamulagira (2001, 2002, 2004, 2006, 2010 and 2011) which all induce large changes in the landscape with the emplacement of new lava fields and scoria cones. From our repetitive Tandem-X DEM production, we have a tool to identify and also quantify in term of size and volume all the topographic changes relative to this past volcanic activity. These parameters are high value information to improve the understanding of the Virunga volcanoes; the accurate estimation of erupted volume and knowledge of structural features associated to past eruptions are key parameters to understand the volcanic system, to ameliorate the hazard assessment, and finally contribute to risk mitigation in a densely populated area.

  2. a Hadoop-Based Algorithm of Generating dem Grid from Point Cloud Data

    NASA Astrophysics Data System (ADS)

    Jian, X.; Xiao, X.; Chengfang, H.; Zhizhong, Z.; Zhaohui, W.; Dengzhong, Z.

    2015-04-01

    Airborne LiDAR technology has proven to be the most powerful tools to obtain high-density, high-accuracy and significantly detailed surface information of terrain and surface objects within a short time, and from which the Digital Elevation Model of high quality can be extracted. Point cloud data generated from the pre-processed data should be classified by segmentation algorithms, so as to differ the terrain points from disorganized points, then followed by a procedure of interpolating the selected points to turn points into DEM data. The whole procedure takes a long time and huge computing resource due to high-density, that is concentrated on by a number of researches. Hadoop is a distributed system infrastructure developed by the Apache Foundation, which contains a highly fault-tolerant distributed file system (HDFS) with high transmission rate and a parallel programming model (Map/Reduce). Such a framework is appropriate for DEM generation algorithms to improve efficiency. Point cloud data of Dongting Lake acquired by Riegl LMS-Q680i laser scanner was utilized as the original data to generate DEM by a Hadoop-based algorithms implemented in Linux, then followed by another traditional procedure programmed by C++ as the comparative experiment. Then the algorithm's efficiency, coding complexity, and performance-cost ratio were discussed for the comparison. The results demonstrate that the algorithm's speed depends on size of point set and density of DEM grid, and the non-Hadoop implementation can achieve a high performance when memory is big enough, but the multiple Hadoop implementation can achieve a higher performance-cost ratio, while point set is of vast quantities on the other hand.

  3. Mit1 Transcription Factor Mediates Methanol Signaling and Regulates the Alcohol Oxidase 1 (AOX1) Promoter in Pichia pastoris*

    PubMed Central

    Wang, Xiaolong; Wang, Qi; Wang, Jinjia; Bai, Peng; Shi, Lei; Shen, Wei; Zhou, Mian; Zhou, Xiangshan; Zhang, Yuanxing; Cai, Menghao

    2016-01-01

    The alcohol oxidase 1 (AOX1) promoter (PAOX1) of Pichia pastoris is the most powerful and commonly used promoter for driving protein expression. However, mechanisms regulating its transcriptional activity are unclear. Here, we identified a Zn(II)2Cys6-type methanol-induced transcription factor 1 (Mit1) and elucidated its roles in regulating PAOX1 activity in response to glycerol and methanol. Mit1 regulated the expression of many genes involved in methanol utilization pathway, including AOX1, but did not participate in peroxisome proliferation and transportation of peroxisomal proteins during methanol metabolism. Structural analysis of Mit1 by performing domain deletions confirmed its specific and critical role in the strict repression of PAOX1 in glycerol medium. Importantly, Mit1, Mxr1, and Prm1, which positively regulated PAOX1 in response to methanol, were bound to PAOX1 at different sites and did not interact with each other. However, these factors cooperatively activated PAOX1 through a cascade. Mxr1 mainly functioned during carbon derepression, whereas Mit1 and Prm1 functioned during methanol induction, with Prm1 transmitting methanol signal to Mit1 by binding to the MIT1 promoter (PMIT1), thus increasingly expressing Mit1 and subsequently activating PAOX1. PMID:26828066

  4. A Review of Discrete Element Method (DEM) Particle Shapes and Size Distributions for Lunar Soil

    NASA Technical Reports Server (NTRS)

    Lane, John E.; Metzger, Philip T.; Wilkinson, R. Allen

    2010-01-01

    As part of ongoing efforts to develop models of lunar soil mechanics, this report reviews two topics that are important to discrete element method (DEM) modeling the behavior of soils (such as lunar soils): (1) methods of modeling particle shapes and (2) analytical representations of particle size distribution. The choice of particle shape complexity is driven primarily by opposing tradeoffs with total number of particles, computer memory, and total simulation computer processing time. The choice is also dependent on available DEM software capabilities. For example, PFC2D/PFC3D and EDEM support clustering of spheres; MIMES incorporates superquadric particle shapes; and BLOKS3D provides polyhedra shapes. Most commercial and custom DEM software supports some type of complex particle shape beyond the standard sphere. Convex polyhedra, clusters of spheres and single parametric particle shapes such as the ellipsoid, polyellipsoid, and superquadric, are all motivated by the desire to introduce asymmetry into the particle shape, as well as edges and corners, in order to better simulate actual granular particle shapes and behavior. An empirical particle size distribution (PSD) formula is shown to fit desert sand data from Bagnold. Particle size data of JSC-1a obtained from a fine particle analyzer at the NASA Kennedy Space Center is also fitted to a similar empirical PSD function.

  5. DEM Modelling of Granule Rearrangement and Fracture Behaviours During a Closed-Die Compaction.

    PubMed

    Furukawa, Ryoichi; Kadota, Kazunori; Noguchi, Tetsuro; Shimosaka, Atsuko; Shirakawa, Yoshiyuki

    2017-08-01

    The closed-die compaction behaviour of D-mannitol granules has been simulated by the discrete element method (DEM) to investigate the granule rearrangement and fracture behaviour during compaction which affects the compactibility of the tablet. The D-mannitol granules produced in a fluidized bed were modelled as agglomerates of primary particles connected by linear spring bonds. The validity of the model granule used in the DEM simulation was demonstrated by comparing to the experimental results of a uniaxial compression test. During uniaxial compression, the numerical results of the force-displacement curve corresponded reasonably well to the experimental data. The closed-die compaction of the modelled granules was carried out to investigate the rearrangement and fracture behaviours of the granule at different upper platen velocities. The forces during closed-die compaction calculated by DEM fluctuated in the low-pressure region due to the rearrangement of granules. A Heckel analysis showed that the force fluctuation occurred at the initial bending region of the Heckel plot, which represents the granule rearrangement and fracture. Furthermore, the upper platen velocity affected the trend of compaction forces, which can lead to compaction failure due to capping. These results could contribute to designing the appropriate granules during closed-die compaction.

  6. Tropical forest heterogeneity from TanDEM-X InSAR and lidar observations in Indonesia

    NASA Astrophysics Data System (ADS)

    De Grandi, Elsa Carla; Mitchard, Edward

    2016-10-01

    Fires exacerbated during El Niño Southern Oscillation are a serious threat in Indonesia leading to the destruction and degradation of tropical forests and emissions of CO2 in the atmosphere. Forest structural changes which occurred due to the 1997-1998 El Niño Southern Oscillation in the Sungai Wain Protection Forest (East Kalimantan, Indonesia), a previously intact forest reserve have led to the development of a range of landcover from secondary forest to areas dominated by grassland. These structural differences can be appreciated over large areas by remote sensing instruments such as TanDEM-X and LiDAR that provide information that are sensitive to vegetation vertical and horizontal structure. One-point statistics of TanDEM-X coherence (mean and CV) and LiDAR CHM (mean, CV) and derived metrics such as vegetation volume and canopy cover were tested for the discrimination between 4 landcover classes. Jeffries-Matusita (JM) separability was high between forest classes (primary or secondary forest) and non-forest (grassland) while, primary and secondary forest were not separable. The study tests the potential and the importance of potential of TanDEM-X coherence and LiDAR observations to characterize structural heterogeneity based on one-point statistics in tropical forest but requires improved characterization using two-point statistical measures.

  7. A Seamless, High-Resolution, Coastal Digital Elevation Model (DEM) for Southern California

    USGS Publications Warehouse

    Barnard, Patrick L.; Hoover, Daniel

    2010-01-01

    A seamless, 3-meter digital elevation model (DEM) was constructed for the entire Southern California coastal zone, extending 473 km from Point Conception to the Mexican border. The goal was to integrate the most recent, high-resolution datasets available (for example, Light Detection and Ranging (Lidar) topography, multibeam and single beam sonar bathymetry, and Interferometric Synthetic Aperture Radar (IfSAR) topography) into a continuous surface from at least the 20-m isobath to the 20-m elevation contour. This dataset was produced to provide critical boundary conditions (bathymetry and topography) for a modeling effort designed to predict the impacts of severe winter storms on the Southern California coast (Barnard and others, 2009). The hazards model, run in real-time or with prescribed scenarios, incorporates atmospheric information (wind and pressure fields) with a suite of state-of-the-art physical process models (tide, surge, and wave) to enable detailed prediction of water levels, run-up, wave heights, and currents. Research-grade predictions of coastal flooding, inundation, erosion, and cliff failure are also included. The DEM was constructed to define the general shape of nearshore, beach and cliff surfaces as accurately as possible, with less emphasis on the detailed variations in elevation inland of the coast and on bathymetry inside harbors. As a result this DEM should not be used for navigation purposes.

  8. A DEM-based partition adjustment for the interpolation of annual cumulative temperature in China

    NASA Astrophysics Data System (ADS)

    Zhao, Jun; Li, Fei; Fu, Haiyue; Tian, Ying; Hu, Zizhi

    2007-06-01

    The spatial interpolation of meteorological elements has more important application value. The interpolation methods of air temperature data have been wildly applied in the large scale region. It has been paid more attentions that taking altitude as a variable was introduced into the interpolation models so as to improve the interpolation precision of air temperature data. In a large area, it is difficult to find the relationship between annual cumulative temperature and altitude according to the distribution of meteorological stations. Compared whit it dividing the study area, introducing interpolation models modified by DEM in the smaller region, we can availably improve the spatial interpolation precision of the annual cumulative temperature. The result shows that: Applied in the partition study area, inverse distance squared method modified by DEM can reduce complexity of spatial data analysis in the process of annual cumulative temperature interpolation. Partition interpolation methods take into account some factors that affect the interpolation results, such as the spatial distribution imbalance of the meteorological stations, altitude and region difference. The methods are fit for the interpolation analysis of the large-scale region. Compared with the tradition interpolation methods such as Kriging, Inverse distance interpolation method, etc., inverse distance squared method modified by DEM has higher interpolation precision of annual cumulative temperature in China.

  9. Fusion of Laser Altimetry Data with Dems Derived from Stereo Imaging Systems

    NASA Astrophysics Data System (ADS)

    Schenk, T.; Csatho, B. M.; Duncan, K.

    2016-06-01

    During the last two decades surface elevation data have been gathered over the Greenland Ice Sheet (GrIS) from a variety of different sensors including spaceborne and airborne laser altimetry, such as NASA's Ice Cloud and land Elevation Satellite (ICESat), Airborne Topographic Mapper (ATM) and Laser Vegetation Imaging Sensor (LVIS), as well as from stereo satellite imaging systems, most notably from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and Worldview. The spatio-temporal resolution, the accuracy, and the spatial coverage of all these data differ widely. For example, laser altimetry systems are much more accurate than DEMs derived by correlation from imaging systems. On the other hand, DEMs usually have a superior spatial resolution and extended spatial coverage. We present in this paper an overview of the SERAC (Surface Elevation Reconstruction And Change detection) system, designed to cope with the data complexity and the computation of elevation change histories. SERAC simultaneously determines the ice sheet surface shape and the time-series of elevation changes for surface patches whose size depends on the ruggedness of the surface and the point distribution of the sensors involved. By incorporating different sensors, SERAC is a true fusion system that generates the best plausible result (time series of elevation changes) a result that is better than the sum of its individual parts. We follow this up with an example of the Helmheim gacier, involving ICESat, ATM and LVIS laser altimetry data, together with ASTER DEMs.

  10. Radiosensitization by misonidazole during recovery of cellular thiols following depletion by BSO or DEM

    SciTech Connect

    McNally, N.J.; Soranson, J.A.

    1989-05-01

    V79 cells have been depleted of their endogenous thiols by treatment with 100 microM BSO for 16-18 hr, or 0.5 mM DEM for 1 hr. The recovery of cellular thiols after removal of the drugs was determined by h.p.l.c. or flow cytometry and the sensitizer enhancement ratio for 100 microM misonidazole was measured as a function of time after removal of the drugs. The SER of 1.2 for control (hypoxic) cells increased to 1.8 for BSO treated (hypoxic) cells and 2.2 for DEM treated ones, when thiol levels were below 10% of controls. The SER and thiol levels returned to control values within 5 hr of removing DEM. After BSO there was little change during the first 5 hr and then a gradual return to normal values by 24 hrs. The major fall in the SER after removal of the drugs occurred as the cellular thiols increased to 60% of control values.

  11. Shoreline Mapping with Integrated HSI-DEM using Active Contour Method

    NASA Astrophysics Data System (ADS)

    Sukcharoenpong, Anuchit

    Shoreline mapping has been a critical task for federal/state agencies and coastal communities. It supports important applications such as nautical charting, coastal zone management, and legal boundary determination. Current attempts to incorporate data from hyperspectral imagery to increase the efficiency and efficacy of shoreline mapping have been limited due to the complexity in processing its data as well as its inferior spatial resolution when compared to multispectral imagery or to sensors such as LiDAR. As advancements in remote-sensing technologies increase sensor capabilities, the ability to exploit the spectral formation carried in hyperspectral images becomes more imperative. This work employs a new approach to extracting shorelines from AVIRIS hyperspectral images by combination with a LiDAR-based DEM using a multiphase active contour segmentation technique. Several techniques, such as study of object spectra and knowledge-based segmentation for initial contour generation, have been employed in order to achieve a sub-pixel level of accuracy and maintain low computational expenses. Introducing a DEM into hyperspectral image segmentation proves to be a useful tool to eliminate misclassifications and improve shoreline positional accuracy. Experimental results show that mapping shorelines from hyperspectral imagery and a DEM can be a promising approach as many further applications can be developed to exploit the rich information found in hyperspectral imagery.

  12. Effects of Scale on DEM Derived Drainage Networks For a High Arctic Wetland Complex

    NASA Astrophysics Data System (ADS)

    Brown, L. C.; Young, K. L.

    2004-05-01

    The ability to automatically generate drainage patterns is a useful tool in hydrologic studies, especially in remote areas where limited data is available. However drainage patterns derived from digital elevation data can be significantly affected by the scale of the data from which they are generated. This study investigates the effects of scaling on drainage patterns extracted from elevation data for a low gradient wetland area on Somerset Island, Nunavut, in the Canadian High Arctic. A series of Digital Elevation Models (DEM's) were created from digitized topographic information at varying resolutions (2.5 m, 5 m. 10 m, 50 m, 100 m, 200 m). Automated drainage network extractions were performed for each resolution grid, using ESRI ArcInfo software. A series of flow networks were created for each resolution DEM using varying minimum stream lengths in order to examine the effects of this variable on flow pattern and direction. The modelled drainage at each resolution was then compared to the `actual' drainage mapped from aerial photography (air photos and low level oblique photographs) and topographic maps to examine differences as a result of scaling. Preliminary results suggest that reproducing correct flow direction was not possible with the coarser resolution DEMs (10 m and up), while the finer resolutions (2.5 m, 5 m) resulted in drainage networks most similar to the mapped drainage.

  13. Parametrisation of a DEM model for railway ballast under different load cases.

    PubMed

    Suhr, Bettina; Six, Klaus

    2017-01-01

    The prediction quality of discrete element method (DEM) models for railway ballast can be expected to depend on three points: the geometry representation of the single particles, the used contact models and the parametrisation using principal experiments. This works aims at a balanced approach, where none of the points is addressed with excessive depth. In a first step, a simple geometry representation is chosen and the simplified Hertz-Mindlin contact model is used. When experimental data of cyclic compression tests and monotonic direct shear tests are considered, the model can be parametrised to fit either one of the two tests, but not both with the same set of parameters. Similar problems can be found in literature for monotonic and cyclic triaxial tests of railway ballast. In this work, the comparison between experiment and simulation is conducted using the entire data of the test, e.g. shear force over shear path curve from the direct shear test. In addition to a visual comparison of the results also quantitative errors based on the sum of squares are defined. To improve the fit of the DEM model to both types of experiments, an extension on the Hertz-Mindlin contact law is used, which introduces additional physical effects (e.g. breakage of edges or yielding). This model introduces two extra material parameters and is successfully parametrised. Using only one set of parameters, the results of the DEM simulation are in good accordance with both experimental cyclic compression test and monotonic directs shear test.

  14. Calibration of DEM parameters on shear test experiments using Kriging method

    NASA Astrophysics Data System (ADS)

    Xavier, Bednarek; Sylvain, Martin; Abibatou, Ndiaye; Véronique, Peres; Olivier, Bonnefoy

    2017-06-01

    Calibration of powder mixing simulation using Discrete-Element-Method is still an issue. Achieving good agreement with experimental results is difficult because time-efficient use of DEM involves strong assumptions. This work presents a methodology to calibrate DEM parameters using Efficient Global Optimization (EGO) algorithm based on Kriging interpolation method. Classical shear test experiments are used as calibration experiments. The calibration is made on two parameters - Young modulus and friction coefficient. The determination of the minimal number of grains that has to be used is a critical step. Simulations of a too small amount of grains would indeed not represent the realistic behavior of powder when using huge amout of grains will be strongly time consuming. The optimization goal is the minimization of the objective function which is the distance between simulated and measured behaviors. The EGO algorithm uses the maximization of the Expected Improvement criterion to find next point that has to be simulated. This stochastic criterion handles with the two interpolations made by the Kriging method : prediction of the objective function and estimation of the error made. It is thus able to quantify the improvement in the minimization that new simulations at specified DEM parameters would lead to.

  15. Suitability of COSMO-SkyMed constellation for radargrammetric DEM generation

    NASA Astrophysics Data System (ADS)

    Conte, Domenico; Bovenga, Fabio; Refice, Alberto; Nitti, Davide O.; Nutricato, Raffaele; Chiaradia, Maria T.

    2014-10-01

    The COSMO-SkyMed (CSK) constellation acquires data from its four SAR X-band satellites in several imaging modes, providing in particular different view angles. The present work investigates the potential of CSK constellation for ground elevation measurement through SAR radargrammetry. We selected an area around Parkfield (California), where several CSK acquisitions are available. We used for radargrammetric processing 2 CSK spotlight image pairs acquired at 1 day of separation, in Same Side Viewing configuration, with baselines of 350 km. Furthermore, a dataset of 33 spotlight images were selected to derive height measurements through both persistent scatterers interferometry(PSI) and interferometric processing of 5 1-day separated pairs included in the dataset. We first predict how the errors in the geometrical parameters and the correlation level between the images impact on the height accuracy. Then, two DEMs were derived by processing the radargrammetric CSK pairs. According to the outcomes of the feasibility analysis, processing parameters were chosen in order to guarantee nominal values of height accuracy within the HRTI Level 3 specifications. The products have a final resolution of 3 m. In order to assess the accuracy of these radargrammetric DEMs, we used the height values provided by the PSI, and an interferometric DEM derived from the CSK tandem-like pairs.

  16. LiDAR DEM for Slope regulations of land development in Taiwan

    NASA Astrophysics Data System (ADS)

    Liu, J.-K.; Yang, M.-S.; Wu, M.-C.; Hsu, W.-C.

    2012-04-01

    Slope gradient is a major parameter for regulating the development of slope-lands in Taiwan. According to official guidelines, only two methods can be adopted, namely the rectangular parcel method and the parcel contouring method. Both of them are manual methods using conventional analogue maps produced by photogrammetric method. As the trend of technology is in favor of adopting digital elevation models for automated production of slope maps and complete coverage of the territory of Taiwan with DEM in 40m, 5m and 1m grids have been mostly completed, it is needed to assess the difference of DEM approaches in comparison to the official approaches which is recognized as the only legal procedure until now. Thus, a 1/1000 contour map in the sloping land of suburban area of New Taipei City is selected for this study. Manual approaches are carried out using the contour lines with 2m intervals. DEM grids of 1m, 5m, and 10m are generated by LiDAR survey. It is shown that the slope maps generated by Eight Neighbors Unweighted method are comparable or even better than the conventional approaches. As the conventional approach is prone to error propagations and uncertainties, the new digital approach should be implemented and enforced in the due process of law.

  17. Pre-2014 mudslides at Oso revealed by InSAR and multi-source DEM analysis

    NASA Astrophysics Data System (ADS)

    Kim, J. W.; Lu, Z.; QU, F.

    2014-12-01

    The landslide is a process that results in the downward and outward movement of slope-reshaping materials including rocks and soils and annually causes the loss of approximately $3.5 billion and tens of casualties in the United States. The 2014 Oso mudslide was an extreme event costing nearly 40 deaths and damaging civilian properties. Landslides are often unpredictable, but in many cases, catastrophic events are repetitive. Historic record in the Oso mudslide site indicates that there have been serial events in decades, though the extent of sliding events varied from time to time. In our study, the combination of multi-source DEMs, InSAR, and time-series InSAR analysis has enabled to characterize the Oso mudslide. InSAR results from ALOS PALSAR show that there was no significant deformation between mid-2006 and 2011. The combination of time-series InSAR analysis and old-dated DEM indicated revealed topographic changes associated the 2006 sliding event, which is confirmed by the difference of multiple LiDAR DEMs. Precipitation and discharge measurements before the 2006 and 2014 landslide events did not exhibit extremely anomalous records, suggesting the precipitation is not the controlling factor in determining the sliding events at Oso. The lack of surface deformation during 2006-2011 and weak correlation between the precipitation and the sliding event, suggest other factors (such as porosity) might play a critical role on the run-away events at this Oso and other similar landslides.

  18. Validation Of DEM Data Dvied From World View 3 Stero Imagery For Low Elevation Majuro Atoll, Marchall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a "massive" data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are nee...

  19. Validation Of DEM Data Dvied From World View 3 Stero Imagery For Low Elevation Majuro Atoll, Marchall Islands

    EPA Science Inventory

    The availability of surface elevation data for the Marshall Islands has been identified as a "massive" data gap for conducting vulnerability assessments and the subsequent development of climate change adaption strategies. Specifically, digital elevation model (DEM) data are nee...

  20. Defining optimal DEM resolutions and point densities for modelling hydrologically sensitive areas in agricultural catchments dominated by microtopography

    NASA Astrophysics Data System (ADS)

    Thomas, I. A.; Jordan, P.; Shine, O.; Fenton, O.; Mellander, P.-E.; Dunlop, P.; Murphy, P. N. C.

    2017-02-01

    Defining critical source areas (CSAs) of diffuse pollution in agricultural catchments depends upon the accurate delineation of hydrologically sensitive areas (HSAs) at highest risk of generating surface runoff pathways. In topographically complex landscapes, this delineation is constrained by digital elevation model (DEM) resolution and the influence of microtopographic features. To address this, optimal DEM resolutions and point densities for spatially modelling HSAs were investigated, for onward use in delineating CSAs. The surface runoff framework was modelled using the Topographic Wetness Index (TWI) and maps were derived from 0.25 m LiDAR DEMs (40 bare-earth points m-2), resampled 1 m and 2 m LiDAR DEMs, and a radar generated 5 m DEM. Furthermore, the resampled 1 m and 2 m LiDAR DEMs were regenerated with reduced bare-earth point densities (5, 2, 1, 0.5, 0.25 and 0.125 points m-2) to analyse effects on elevation accuracy and important microtopographic features. Results were compared to surface runoff field observations in two 10 km2 agricultural catchments for evaluation. Analysis showed that the accuracy of modelled HSAs using different thresholds (5%, 10% and 15% of the catchment area with the highest TWI values) was much higher using LiDAR data compared to the 5 m DEM (70-100% and 10-84%, respectively). This was attributed to the DEM capturing microtopographic features such as hedgerow banks, roads, tramlines and open agricultural drains, which acted as topographic barriers or channels that diverted runoff away from the hillslope scale flow direction. Furthermore, the identification of 'breakthrough' and 'delivery' points along runoff pathways where runoff and mobilised pollutants could be potentially transported between fields or delivered to the drainage channel network was much higher using LiDAR data compared to the 5 m DEM (75-100% and 0-100%, respectively). Optimal DEM resolutions of 1-2 m were identified for modelling HSAs, which balanced the need

  1. Combined DEM Extration Method from StereoSAR and InSAR

    NASA Astrophysics Data System (ADS)

    Zhao, Z.; Zhang, J. X.; Duan, M. Y.; Huang, G. M.; Yang, S. C.

    2015-06-01

    A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn't require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.

  2. Dem Extraction from WORLDVIEW-3 Stereo-Images and Accuracy Evaluation

    NASA Astrophysics Data System (ADS)

    Hu, F.; Gao, X. M.; Li, G. Y.; Li, M.

    2016-06-01

    This paper validates the potentials of Worldview-3 satellite images in large scale topographic mapping, by choosing Worldview-3 along-track stereo-images of Yi Mountain area in Shandong province China for DEM extraction and accuracy evaluation. Firstly, eighteen accurate and evenly-distributed GPS points are collected in field and used as GCPs/check points, the image points of which are accurately measured, and also tie points are extracted from image matching; then, the RFM-based block adjustment to compensate the systematic error in image orientation is carried out and the geo-positioning accuracy is calculated and analysed; next, for the two stereo-pairs of the block, DSMs are separately constructed and mosaicked as an entirety, and also the corresponding DEM is subsequently generated; finally, compared with the selected check points from high-precision airborne LiDAR point cloud covering the same test area, the accuracy of the generated DEM with 2-meter grid spacing is evaluated by the maximum (max.), minimum (min.), mean and standard deviation (std.) values of elevation biases. It is demonstrated that, for Worldview-3 stereo-images used in our research, the planimetric accuracy without GCPs is about 2.16 m (mean error) and 0.55 (std. error), which is superior to the nominal value, while the vertical accuracy is about -1.61 m (mean error) and 0.49 m (std. error); with a small amount of GCPs located in the center and four corners of the test area, the systematic error can be well compensated. The std. value of elevation biases between the generated DEM and the 7256 LiDAR check points are about 0.62 m. If considering the potential uncertainties in the image point measurement, stereo matching and also elevation editing, the accuracy of generating DEM from Worldview-3 stereo-images should be more desirable. Judging from the results, Worldview-3 has the potential for 1:5000 or even larger scale mapping application.

  3. Use of thermal infrared pictures for retrieving intertidal DEM by the waterline method: advantages and limitations

    NASA Astrophysics Data System (ADS)

    Gaudin, D.; Delacourt, C.; Allemand, P.

    2010-12-01

    Digital Elevation Models (DEM) of the intertidal zones have a growing interest for ecological and land development purposes. They are also a fundamental tool for monitoring current sedimentary movements in those low energy environments. Such DEMs have to be constructed with a centimetric resolution as the topographic changes are not predictable and as sediment displacements are weak. Direct construction of DEM by GPS in these muddy environment is difficult: photogrammetric techniques are not efficient on uniform coloured surfaces and terrestrial laser scans are difficult to stabilize on the mud, due to humidity. In this study, we propose to improve and to apply the waterline method to retrieve DEMs in intertidal zones. This technique is based on monitoring accurately the boundary between sand and water during a whole tide rise with thermal infrared images. The DEM is made by stacking all these lines calibrated by an immersed pressure sensor. Using thermal infrared pictures, instead of optical ones, improves the detection of the waterline, since mud and water have very different responses to sun heating and a large emissivity contrast. However, temperature retrieving from thermal infrared data is not trivial, since the luminance of an object is the sum of a radiative part and a reflexive part, whose relative proportions are given by the emissivity. In the following equation, B accounts for the equivalent blackbody luminance, and Linc is the incident luminance : Ltot}=L{rad}+L_{refl=ɛ B+(1-ɛ )Linc The infrared waterline technique has been used for the monitoring of a beach located on the Aber Benoit, 8.5km away from the open sea. The site is mainly constituted of mud, and waves are very small (less than one centimeter high), which are the ideal conditions for using the waterline method. A few measurements have been made to make differential heigh maps of sediments. We reached a mean resolution of 2cm and a vertical accuracy better than one centimeter. The results

  4. Coastal Digital Elevation Models (DEMs) for tsunami hazard assessment on the French coasts

    NASA Astrophysics Data System (ADS)

    Maspataud, Aurélie; Biscara, Laurie; Hébert, Hélène; Schmitt, Thierry; Créach, Ronan

    2015-04-01

    Building precise and up-to-date coastal DEMs is a prerequisite for accurate modeling and forecasting of hydrodynamic processes at local scale. Marine flooding, originating from tsunamis, storm surges or waves, is one of them. Some high resolution DEMs are being generated for multiple coast configurations (gulf, embayment, strait, estuary, harbor approaches, low-lying areas…) along French Atlantic and Channel coasts. This work is undertaken within the framework of the TANDEM project (Tsunamis in the Atlantic and the English ChaNnel: Definition of the Effects through numerical Modeling) (2014-2017). DEMs boundaries were defined considering the vicinity of French civil nuclear facilities, site effects considerations and potential tsunamigenic sources. Those were identified from available historical observations. Seamless integrated topographic and bathymetric coastal DEMs will be used by institutions taking part in the study to simulate expected wave height at regional and local scale on the French coasts, for a set of defined scenarii. The main tasks were (1) the development of a new capacity of production of DEM, (2) aiming at the release of high resolution and precision digital field models referred to vertical reference frameworks, that require (3) horizontal and vertical datum conversions (all source elevation data need to be transformed to a common datum), on the basis of (4) the building of (national and/or local) conversion grids of datum relationships based on known measurements. Challenges in coastal DEMs development deal with good practices throughout model development that can help minimizing uncertainties. This is particularly true as scattered elevation data with variable density, from multiple sources (national hydrographic services, state and local government agencies, research organizations and private engineering companies) and from many different types (paper fieldsheets to be digitized, single beam echo sounder, multibeam sonar, airborne laser

  5. Creating High Quality DEMs of Large Scale Fluvial Environments Using Structure-from-Motion

    NASA Astrophysics Data System (ADS)

    Javernick, L. A.; Brasington, J.; Caruso, B. S.; Hicks, M.; Davies, T. R.

    2012-12-01

    During the past decade, advances in survey and sensor technology have generated new opportunities to investigate the structure and dynamics of fluvial systems. Key geomatic technologies include the Global Positioning System (GPS), digital photogrammetry, LiDAR, and terrestrial laser scanning (TLS). The application of such has resulted in a profound increase in the dimensionality of topographic surveys - from cross-sections to distributed 3d point clouds and digital elevation models (DEMs). Each of these technologies have been used successfully to derive high quality DEMs of fluvial environments; however, they often require specialized and expensive equipment, such as a TLS or large format camera, bespoke platforms such as survey aircraft, and consequently make data acquisition prohibitively expensive or highly labour intensive, thus restricting the extent and frequency of surveys. Recently, advances in computer vision and image analysis have led to development of a novel photogrammetric approach that is fully automated and suitable for use with simple compact (non-metric) cameras. In this paper, we evaluate a new photogrammetric method, Structure-from-Motion (SfM), and demonstrate how this can be used to generate DEMs of comparable quality to airborne LiDAR, using consumer grade cameras at low costs. Using the SfM software PhotoScan (version 0.8.5), high quality DEMs were produced for a 1.6 km reach and a 3.3 km reach of the braided Ahuriri River, New Zealand. Photographs used for DEM creation were acquired from a helicopter flying at 600 m and 800 m above ground level using a consumer grade 10.1mega-pixel, non-metric digital camera, resulting in object space resolution imagery of 0.12 m and 0.16 m respectively. Point clouds for the two study reaches were generated using 147 and 224 photographs respectively, and were extracted automatically in an arbitrary coordinate system; RTK-GPS located ground control points (GCPs) were used to define a 3d non

  6. Coupling photogrammetric data with DFN-DEM model for rock slope hazard assessment

    NASA Astrophysics Data System (ADS)

    Donze, Frederic; Scholtes, Luc; Bonilla-Sierra, Viviana; Elmouttie, Marc

    2013-04-01

    Structural and mechanical analyses of rock mass are key components for rock slope stability assessment. The complementary use of photogrammetric techniques [Poropat, 2001] and coupled DFN-DEM models [Harthong et al., 2012] provides a methodology that can be applied to complex 3D configurations. DFN-DEM formulation [Scholtès & Donzé, 2012a,b] has been chosen for modeling since it can explicitly take into account the fracture sets. Analyses conducted in 3D can produce very complex and unintuitive failure mechanisms. Therefore, a modeling strategy must be established in order to identify the key features which control the stability. For this purpose, a realistic case is presented to show the overall methodology from the photogrammetry acquisition to the mechanical modeling. By combining Sirovision and YADE Open DEM [Kozicki & Donzé, 2008, 2009], it can be shown that even for large camera to rock slope ranges (tested about one kilometer), the accuracy of the data are sufficient to assess the role of the structures on the stability of a jointed rock slope. In this case, on site stereo pairs of 2D images were taken to create 3D surface models. Then, digital identification of structural features on the unstable block zone was processed with Sirojoint software [Sirovision, 2010]. After acquiring the numerical topography, the 3D digitalized and meshed surface was imported into the YADE Open DEM platform to define the studied rock mass as a closed (manifold) volume to define the bounding volume for numerical modeling. The discontinuities were then imported as meshed planar elliptic surfaces into the model. The model was then submitted to gravity loading. During this step, high values of cohesion were assigned to the discontinuities in order to avoid failure or block displacements triggered by inertial effects. To assess the respective role of the pre-existing discontinuities in the block stability, different configurations have been tested as well as different degree of

  7. On the COSMO-SkyMed Exploitation for Interferometric DEM Generation

    NASA Astrophysics Data System (ADS)

    Teresa, C. M.; Raffaele, N.; Oscar, N. D.; Fabio, B.

    2011-12-01

    DEM products for Earth observation space-borne applications are being to play a role of increasing importance due to the new generation of high resolution sensors (both optical and SAR). These new sensors demand elevation data for processing and, on the other hand, they provide new possibilities for DEM generation. Till now, for what concerns interferometric DEM, the Shuttle Radar Topography Mission (SRTM) has been the reference product for scientific applications all over the world. SRTM mission [1] had the challenging goal to meet the requirements for a homogeneous and reliable DEM fulfilling the DTED-2 specifications. However, new generation of high resolution sensors (including SAR) pose new requirements for elevation data in terms of vertical precision and spatial resolution. DEM are usually used as ancillary input in different processing steps as for instance geocoding and Differential SAR Interferometry. In this context, the recent SAR missions of DLR (TerraSAR-X and TanDEM-X) and ASI (COSMO-SkyMed) can play a promising role thanks to their high resolution both in space and time. In particular, the present work investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. The recent scientific works, [2] and [3], have shown the advantages of using CSK in the monitoring of terrain deformations caused by landslides, earthquakes, etc. On the other hand, thanks to the high spatial resolution, CSK appears to be very promising in monitoring man-made structures, such as buildings, bridges, railways and highways, thus enabling new potential applications (urban applications, precise DEM, etc.). We present results obtained by processing both SPOTLIGHT and STRIPMAP acquisitions through standard SAR Interferometry as well as multi-pass interferometry [4] with the aim of measuring ground elevation. Acknowledgments

  8. 1D-Messungen physiologischer Bewegungen am Hals mit optischer Kohärenztomographie

    NASA Astrophysics Data System (ADS)

    Dämgen, M.; Schwab, B.; Lenarz, Th.; Leinung, M.

    In der Chirurgie insbesondere bei onkologischen Fragestellungen kommt es zu Grenzsituationen, in denen es gilt, Gewebeverbände mit hoher Genauigkeit aufzutrennen, z.B. bei Infiltration von Gefäßwänden oder Nervenstrukturen durch Tumorausläufer. Oft könnte eine physiologisch funktioneil wichtige Struktur erhalten werden, wenn ein chirurgisches Instrument existierte, das mit einer überaus hohen Präszision arbeitet. Hierfür ist ein (ultra-)kurzgepulster Laser geeignet, der bei kleinem Focus und minimalen thermischen Wechselwirkungen lediglich vernachlässigbare Kollateralschäden im umgebenden Gewebe erzeugt. Allerdings ist ein solches System nicht mehr allein durch den Operateur kontrollierbar. Daher wurde die Idee entwickelt, ein automatisiertes Assistenzsystem zu designen, das mit einem in entsprechender Genauigkeit arbeitenden Sensor (optische Kohärenztumographie, OCT) und einem Femtosekunden(fs)-Laser als Aktor teilautonom kritische Schritte des operativen Eingriffs unter der Kontrolle des Operateurs vornimmt. Die Vorbedingung eines solchen Systemes jedoch ist die Anpassung an physiologische Bewegungen im OP-Gebiet. Zur Messpooletablierung müssen diese physiologischen Bewegungen aufgezeichnet werden mit der den Dimensionen erforderlichen Präzision.

  9. Collaborative Research and Education: The Cairo University/MIT Technological Planning Program.

    ERIC Educational Resources Information Center

    Moavenzadeh, Fred

    1988-01-01

    Introduces the Technology and Development Program (TDP) at the Massachusetts Institute of Technology (MIT) that helps outside organizations with resources and knowledge in the area of science, technology, and development. Describes a program example including background, objectives, and activities. Lists nine reasons for the program's success. (YP)

  10. NASIC at MIT; Phase 1 Report, 16 July 1973 - 28 February 1974.

    ERIC Educational Resources Information Center

    Benenfeld, Alan R.; And Others

    An experimental, pilot operation of computer-based reference search services to users on a fee-for-service basis was initiated at M.I.T. as the first module in the development of the Northeast Academic Science Information Center (NASIC) under a New England Board of Higher Education (NEBHE) program. The development encompassed, among other tasks,…

  11. On the MIT Bag Model in the Non-relativistic Limit

    NASA Astrophysics Data System (ADS)

    Arrizabalaga, N.; Le Treust, L.; Raymond, N.

    2017-09-01

    This paper is devoted to the spectral investigation of the MIT bag model, that is, the Dirac operator on a smooth and bounded domain of R^3 with certain boundary conditions. When the mass m goes to {±∞}, we provide spectral asymptotic results.

  12. How Much Have They Retained? Making Unseen Concepts Seen in a Freshman Electromagnetism Course at MIT

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Hult, Erin; Breslow, Lori; Belcher, John W.

    2007-01-01

    The introductory freshmen electromagnetism course at MIT has been taught since 2000 using a studio physics format entitled TEAL--Technology Enabled Active Learning. TEAL has created a collaborative, hands-on environment where students carry out desktop experiments, submit web-based assignments, and have access to a host of visualizations and…

  13. Status of High Intensity Polarized Electron Gun at Mit-Bates

    NASA Astrophysics Data System (ADS)

    Tsentalovich, E.; Bessuille, J.; Tiunov, M.

    2011-01-01

    MIT-Bates, in collaboration with BNL, has developed a high intensity polarized electron gun for the eRHIC project. The gun implements large area cathode, ring-shaped beam and active cathode cooling. The paper describes the current status of the project.

  14. Rapid Confirmation of Listeria spp. with the MIT 1000 Microbial Identification System

    USDA-ARS?s Scientific Manuscript database

    Methods that can rapidly confirm the identification of foodborne pathogens are highly desired. The USDA has recently entered into a collaborative research agreement with Micro Imaging Technology to evaluate their MIT 1000 microbial identification system for its ability to identify Listeria species ...

  15. When Alcohol Kills, Who Is Responsible? MIT's Inaction Blamed for Contributing to Death of a Freshman.

    ERIC Educational Resources Information Center

    Reisberg, Leo

    1998-01-01

    The alcohol-related death of a Massachusetts Institute of Technology (MIT) freshman has focused attention on problems in the institution's housing policies and fraternity system, including unclear policy about housing and long-ignored complaints about hazing and dangerous drinking in the Greek system. (MSE)

  16. Aus Wirtschaft und Betrieb. Biomasse: Gewinnung und Verarbeitung mit Profilschal-maschinen

    Treesearch

    P. Koch

    1977-01-01

    1963 wurden in den Südstaaten der USA nur 30% der oberund unterirdischen Biomasse der geernteten sog. Southern pines für Schnittholz und Zellstoff verwertet bzw. als getrockneies, gehobletes und abgelängtes Schnittholz oder als Kraftpapier verkauft. Keine der zusammen mit den Kiefern vorkommenden Laubholzarten wurde bisher in nennenswertem Umfan verwertet. Auch heute...

  17. [An arrhythmia ECG analog signal generator using standard MIT-BIH arrhythmia database].

    PubMed

    Wang, Ying; Zhang, Yong; Fang, Zu-xiang

    2005-07-01

    Microchip MSP430F149 is used to control DAC to attain an amplification-controllable analog output of data of MIT-BIH Arrhythmia Database which is useful in testing medical machines. Data are written into Smart Media (SM) Card with Fat Format to make convenient the replacement of database.

  18. How Much Have They Retained? Making Unseen Concepts Seen in a Freshman Electromagnetism Course at MIT

    ERIC Educational Resources Information Center

    Dori, Yehudit Judy; Hult, Erin; Breslow, Lori; Belcher, John W.

    2007-01-01

    The introductory freshmen electromagnetism course at MIT has been taught since 2000 using a studio physics format entitled TEAL--Technology Enabled Active Learning. TEAL has created a collaborative, hands-on environment where students carry out desktop experiments, submit web-based assignments, and have access to a host of visualizations and…

  19. ComMIT and Tweb Integration: Global Tsunami Modeling Done Locally

    NASA Astrophysics Data System (ADS)

    Kamb, L.; Moore, C. W.; Burger, E. F.

    2014-12-01

    Tweb is a web-based tsunami modeling research tool that was developed to provide distributed and remote access to the modeling and forecasting infrastructure developed for operational use at NOAA's Center for Tsunami Research (NCTR). ComMIT is a desktop application providing a powerful and fully functional, yet easy-to use graphical user interface to the NCTR-developed MOST tsunami forecasting model. ComMIT is a self-contained downloadable application available from NCTR for use by qualified and novice modelers alike. We have recently added functionality that allows ComMIT to retrieve the prefered model solution for tsunami events from the Tweb Web Service. A ComMIT user with access to high resolution coastal bathymetry can generate detailed inundation models for real or synthetic events for their areas of interest. Then with the push of a button, the ComMIT user can upload their model results to Tweb where a community of tsunami modelers and forecasters can see these model results displayed in Tweb, along with other operational and contributed inundation forecast models. Besides the crowdsourcing aspect of tsunami modeling that will allow tsunami forecasters to get inundation model inputs from areas they normally would not consider, these contributed flooding models could provide forecasters with an early model solution verification capability by allowing model result comparisons with local tide gauge data in areas where operational models have not been developed. In addition, with the proper training this tool is very useful for education and as a vehicle for community tsunami hazard assessment. We will illustrate the model solution and results interchange capabilities now possible with these two applications.

  20. Stream Morphologic Measurements from Airborne Laser Swath Mapping: Comparisons with Field Surveys, Traditional DEMs, and Aerial Photographs

    NASA Astrophysics Data System (ADS)

    Snyder, N. P.; Schultz, L. L.

    2005-12-01

    Precise measurement of stream morphology over entire watersheds is one of the great research opportunities provided by airborne laser swath mapping (ALSM). ALSM surveys allow for rapid quantification of factors, such as channel width and gradient, that control stream hydraulic and ecologic properties. We compare measurements from digital elevation models (DEMs) derived from ALSM data collected by the National Center for Airborne Laser Mapping (NCALM) to field surveys, traditional DEMs (rasterized from topographic maps), and aerial photographs. The field site is in the northern Black Mountains in arid Death Valley National Park (California). The area is unvegetated, and therefore is excellent for testing DEM analysis methods because the ALSM data required minimal filtering, and the resulting DEM contains relatively few unphysical sinks. Algorithms contained in geographic information systems (GIS) software used to extract stream networks from DEMs yield best results where streams are steep enough for resolvable pixel-to-pixel elevation change, and channel width is on the order of pixel resolution. This presents a new challenge with ALSM-derived DEMs because the pixel size (1 m) is often an order of magnitude or more smaller than channel width. We find the longitudinal profile of Gower Gulch in the northern Black Mountains (~4 km total length) extracted using the ALSM DEM and a flow accumulation algorithm is 14% longer than a traditional 10-m DEM, and 13% longer than a field survey. These differences in length (and therefore gradient) are due to the computed channel path following small-scale topographic variations within the channel bottom that are not relevant during high flows. However, visual analysis of shaded-relief images created from high-resolution ALSM data is an excellent method for digitizing channel banks and thalweg paths. We used these lines to measure distance, elevation, and width. In Gower Gulch, the algorithm-derived profile is 10% longer than that

  1. Elevation validation and geomorphic metric comparison with focus on ASTER GDEM2, SRTM- C, ALOS World 3D, and TanDEM-X

    NASA Astrophysics Data System (ADS)

    Purinton, Benjamin; Bookhagen, Bodo

    2017-04-01

    Geomorphologists use digital elevation models (DEMs) to quantify changes in topography - often without rigorous accuracy assessments. In this study we validate and compare elevation accuracy and derived geomorphic metrics from the current generation of satellite-derived DEMs on the southern Central Andean Plateau. The average elevation of 3.7 km, diverse topography and relief, lack of vegetation, and clear skies create ideal conditions for remote sensing in this study area. DEMs at resolutions of 5-30 m are sourced from open-access, research agreement, and commercial outlets, with a focus on the 30 m SRTM-C, 30 m ASTER GDEM2, 12 m TanDEM-X, and 5 m ALOS World 3D data. In addition to these edited products, manually generated DEMs included 10 m single-CoSSC TerraSAR-X / TanDEM-X DEMs and a 30 m stacked ASTER L1A stereopair DEM. We assessed vertical accuracy by comparing standard deviations (SD) of the DEM elevation versus 307,509 differential GPS (dGPS) measurements with < 0.5 m vertical accuracy, acquired across 4,000 m of elevation. Vertical SD was 3.33 m, 9.48 m, 6.93 m, 1.97 m, 2.02-3.83 m, and 1.64 m for the 30 m SRTM-C, 30 m ASTER GDEM2, 30 m stacked ASTER, 12 m TanDEM-X, 10 m single-CoSSC TerraSAR-X / TanDEM-X DEMs, and 5 m ALOS World 3D, respectively. Analysis of vertical uncertainty with respect to terrain elevation, slope, and aspect revealed the high performance across these attributes of the 30 m SRTM-C, 12 m TanDEM-X, and 5 m ALOS World 3D DEMs. The 10 m single-CoSSC TerraSAR-X / TanDEM-X DEMs and the 30 m ASTER GDEM2 displayed slight aspect biases, which were removed in their stacked counterparts (TanDEM-X and the stacked ASTER DEMs). We selected the high quality 30 m SRTM-C, 12 m TanDEM-X, and 5 m ALOS World 3D for geomorphic metric comparison in a 66 sqkm catchment with a clear river knickpoint. For trunk channel profiles analyzed with chi plots, consistent m/n values of 0.49-0.57 were found regardless of DEM resolution or SD. Hillslopes were analyzed

  2. Analysis and Validation of Grid dem Generation Based on Gaussian Markov Random Field

    NASA Astrophysics Data System (ADS)

    Aguilar, F. J.; Aguilar, M. A.; Blanco, J. L.; Nemmaoui, A.; García Lorca, A. M.

    2016-06-01

    Digital Elevation Models (DEMs) are considered as one of the most relevant geospatial data to carry out land-cover and land-use classification. This work deals with the application of a mathematical framework based on a Gaussian Markov Random Field (GMRF) to interpolate grid DEMs from scattered elevation data. The performance of the GMRF interpolation model was tested on a set of LiDAR data (0.87 points/m2) provided by the Spanish Government (PNOA Programme) over a complex working area mainly covered by greenhouses in Almería, Spain. The original LiDAR data was decimated by randomly removing different fractions of the original points (from 10% to up to 99% of points removed). In every case, the remaining points (scattered observed points) were used to obtain a 1 m grid spacing GMRF-interpolated Digital Surface Model (DSM) whose accuracy was assessed by means of the set of previously extracted checkpoints. The GMRF accuracy results were compared with those provided by the widely known Triangulation with Linear Interpolation (TLI). Finally, the GMRF method was applied to a real-world case consisting of filling the LiDAR-derived DSM gaps after manually filtering out non-ground points to obtain a Digital Terrain Model (DTM). Regarding accuracy, both GMRF and TLI produced visually pleasing and similar results in terms of vertical accuracy. As an added bonus, the GMRF mathematical framework makes possible to both retrieve the estimated uncertainty for every interpolated elevation point (the DEM uncertainty) and include break lines or terrain discontinuities between adjacent cells to produce higher quality DTMs.

  3. High mobility of large mass movements: a study by means of FEM/DEM simulations

    NASA Astrophysics Data System (ADS)

    Manzella, I.; Lisjak, A.; Grasselli, G.

    2013-12-01

    Large mass movements, such as rock avalanches and large volcanic debris avalanches are characterized by extremely long propagation, which cannot be modelled using normal sliding friction law. For this reason several studies and theories derived from field observation, physical theories and laboratory experiments, exist to try to explain their high mobility. In order to investigate more into deep some of the processes recalled by these theories, simulations have been run with a new numerical tool called Y-GUI based on the Finite Element-Discrete Element Method FEM/DEM. The FEM/DEM method is a numerical technique developed by Munjiza et al. (1995) where Discrete Element Method (DEM) algorithms are used to model the interaction between different solids, while Finite Element Method (FEM) principles are used to analyze their deformability being also able to explicitly simulate material sudden loss of cohesion (i.e. brittle failure). In particular numerical tests have been run, inspired by the small-scale experiments done by Manzella and Labiouse (2013). They consist of rectangular blocks released on a slope; each block is a rectangular discrete element made of a mesh of finite elements enabled to fragment. These simulations have highlighted the influence on the propagation of block packing, i.e. whether the elements are piled into geometrical ordinate structure before failure or they are chaotically disposed as a loose material, and of the topography, i.e. whether the slope break is smooth and regular or not. In addition the effect of fracturing, i.e. fragmentation, on the total runout have been studied and highlighted.

  4. A detailed observation of a LMC supernova remnant DEM L241 with XMM-Newton

    NASA Astrophysics Data System (ADS)

    Bamba, A.; Ueno, M.; Nakajima, H.; Mori, K.; Koyama, K.

    2006-05-01

    We report on an XMM-Newton observation of the supernova remnant (SNR) DEM L241 in the Large Magellanic Cloud. In the soft band image, the emission shows an elongated structure, like a killifish, with a central compact source. The compact source is point-like, and named XMMU J053559.3-673509. The source spectrum is reproduced well by a power-law model with a photon index of Γ = 1.57 (1.51-1.62); and the intrinsic luminosity is 2.2 × 1035~erg~s-1 in the 0.5-10.0 keV band, with an assumed distance of 50 kpc. The source has neither significant coherent pulsations in 2.0 × 10-3-8.0 Hz nor time variabilities. Its luminosity and spectrum suggest that the source might be a pulsar wind nebula (PWN) in DEM L241. The spectral feature classifies this source as rather bright and hard PWN, which is similar to those in Kes 75 and B0540-693. The elongated diffuse structure can be divided into a "Head" and "Tail", and both have soft and line-rich spectra. Their spectra are reproduced well by a plane-parallel shock plasma (vpshock) model with a temperature of 0.3-0.4 keV, over-abundance in O and Ne, and a relative under-abundance in Fe. Such an abundance pattern and the morphology imply both that the emission is from the ejecta of the SNR and that the progenitor of DEM L241 is a very massive star, more than 20 M_⊙. This result is also supported by the existence of the central point source and an OB star association, LH 88. The total thermal energy and plasma mass are ~4 × 1050 erg and ~200~M_⊙, respectively.

  5. Simulation of a tablet coating process at different scales using DEM.

    PubMed

    Boehling, P; Toschkoff, G; Just, S; Knop, K; Kleinebudde, P; Funke, A; Rehbaum, H; Rajniak, P; Khinast, J G

    2016-10-10

    Spray coating of tablets is an important unit operation in the pharmaceutical industry and is mainly used for modified release, enteric protection, better appearance and brand recognition. It can also be used to apply an additional active pharmaceutical ingredient to the tablet core. Scale-up of such a process is an important step in commercialization. However, scale-up is not trivial and frequently, at manufacturing scales the required coating quality cannot be reached. Thus, we propose a method where laboratory experiments are carried out, yet scale-up is done via computational methods, i.e., by extrapolating results to larger scales. In the recent years, the Discrete Element Method (DEM) has widely been used to simulate tablet behavior in a laboratory scale drum coater. Due the increasing computational power and more sophisticated DEM algorithms, it has become possible to simulate millions of particles on regular PCs and model industrial scale tablet coating devices. In this work, simulations were performed on the laboratory, pilot and industrial scales and DEM was used to study how different scale-up rules influence the bed behavior on larger scales. The material parameters of the tablets were measured in the laboratory and a glued sphere approach was applied to model the tablet shape. The results include a vast amount of qualitative and quantitative data at the different scales. In conclusion, the evolution of the inter-tablet coating variation for the different scales and process parameters is presented. The results suggest that keeping the Froude number constant during the scale up process leads to faster processes as the cycle time is shorter and the spray residence time is more uniform when compared to keeping the circumferential velocity constant. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Identification of Quaternary Faults in Southwest Western Australia Using DEM-based Hill Shading

    NASA Astrophysics Data System (ADS)

    Clark, D.; Collins, C. D.

    2004-12-01

    In Australia, the extreme infrequency of large earthquake events means that the historic record of seismicity is poorly suited to the task of assessing seismic hazard. Paleoseismological investigations provide the only viable avenue to obtain constraints on the recurrence intervals of large and damaging earthquakes. However, the prehistoric record is compromised by difficulties related to finding direct evidence for large earthquakes (e.g. fault scarps), which may be subtle or relatively short-lived in the landscape. In recent times, high resolution digital elevation models (DEMs) have emerged as an important tool for defining and mapping of areas of probable elevated earthquake hazard. An examination of selected Shuttle Radar Tomography Mission (SRTM) 3 second DEM tiles and a 10 m resolution Department of Land Administration DEM has resulted in the identification of seven previously unrecognised fault scarps of probably Quaternary age in the southwest of Western Australia (SWWA). This doubles the number of Quaternary scarps known from SWWA, and is an important advance in defining areas prone to large earthquakes. The new features range in length from ~15 km to over 45 km, and from ~1.5 m to 7.5 m in height. As might be expected given the prevailing E-W regional compressive stress direction, the scarps are dominantly north-trending. However, most scarps are also arranged within a broad ESE-trending belt. This belt aligns with oceanic transform faults to the west of Australia relating to the break up with India. Of the fourteen scarps only two have been the subject of detailed palaeoseismic investigation to determine recurrence for large events. Ongoing research seeks to characterise seismicity on these scarps and further explore their large-scale relationship to each other, and to the architecture of the Australian plate. This work has the potential to greatly enhance our understanding of the drivers behind seismicity in intraplate Australia, and hence improve

  7. Development and Evaluation of Simple Measurement System Using the Oblique Photo and dem

    NASA Astrophysics Data System (ADS)

    Nonaka, H.; Sasaki, H.; Fujimaki, S.; Naruke, S.; Kishimoto, H.

    2016-06-01

    When a disaster occurs, we must grasp and evaluate its damage as soon as possible. Then we try to estimate them from some kind of photographs, such as surveillance camera imagery, satellite imagery, photographs taken from a helicopter and so on. Especially in initial stage, estimation of decent damage situation for a short time is more important than investigation of damage situation for a long time. One of the source of damage situation is the image taken by surveillance camera, satellite sensor and helicopter. If we can measure any targets in these imagery, we can estimate a length of a lava flow, a reach of a cinder and a sediment volume in volcanic eruption or landslide. Therefore in order to measure various information for a short time, we developed a simplified measurement system which uses these photographs. This system requires DEM in addition to photographs, but it is possible to use previously acquired DEM. To measure an object, we require only two steps. One is the determination of the position and the posture in which the photograph is shot. We determine these parameters using DEM. The other step is the measurement of an object in photograph. In this paper, we describe this system and show the experimental results to evaluate this system. In this experiment we measured the top of Mt. Usu by using two measurement method of this system. Then we can measure it about one hour and the difference between the measurement results and the airborne LiDAR data are less than 10 meter.

  8. ArcticDEM; A Publically Available, High Resolution Elevation Model of the Arctic

    NASA Astrophysics Data System (ADS)

    Morin, Paul; Porter, Claire; Cloutier, Michael; Howat, Ian; Noh, Myoung-Jong; Willis, Michael; Bates, Brian; Willamson, Cathleen; Peterman, Kennith

    2016-04-01

    A Digital Elevation Model (DEM) of the Arctic is needed for a large number of reasons, including: measuring and understanding rapid, ongoing changes to the Arctic landscape resulting from climate change and human use and mitigation and adaptation planning for Arctic communities. The topography of the Arctic is more poorly mapped than most other regions of Earth due to logistical costs and the limits of satellite missions with low-latitude inclinations. A convergence of civilian, high-quality sub-meter stereo imagery; petascale computing and open source photogrammetry software has made it possible to produce a complete, very high resolution (2 to 8-meter posting), elevation model of the Arctic. A partnership between the US National Geospatial-intelligence Agency and a team led by the US National Science Foundation funded Polar Geospatial Center is using stereo imagery from DigitalGlobe's Worldview-1, 2 and 3 satellites and the Ohio State University's Surface Extraction with TIN-based Search-space Minimization (SETSM) software running on the University of Illinois's Blue Water supercomputer to address this challenge. The final product will be a seemless, 2-m posting digital surface model mosaic of the entire Arctic above 60 North including all of Alaska, Greenland and Kamchatka. We will also make available the more than 300,000 individual time-stamped DSM strip pairs that were used to assemble the mosaic. The Arctic DEM will have a vertical precision of better than 0.5m and can be used to examine changes in land surfaces such as those caused by permafrost degradation or the evolution of arctic rivers and floodplains. The data set can also be used to highlight changing geomorphology due to Earth surface mass transport processes occurring in active volcanic and glacial environments. When complete the ArcticDEM will catapult the Arctic from the worst to among the best mapped regions on Earth.

  9. Reanalysis of the DEMS Nested Case-Control Study of Lung Cancer and Diesel Exhaust: Suitability for Quantitative Risk Assessment

    PubMed Central

    Crump, Kenny S; Van Landingham, Cynthia; Moolgavkar, Suresh H; McClellan, Roger

    2015-01-01

    The International Agency for Research on Cancer (IARC) in 2012 upgraded its hazard characterization of diesel engine exhaust (DEE) to “carcinogenic to humans.” The Diesel Exhaust in Miners Study (DEMS) cohort and nested case-control studies of lung cancer mortality in eight U.S. nonmetal mines were influential in IARC’s determination. We conducted a reanalysis of the DEMS case-control data to evaluate its suitability for quantitative risk assessment (QRA). Our reanalysis used conditional logistic regression and adjusted for cigarette smoking in a manner similar to the original DEMS analysis. However, we included additional estimates of DEE exposure and adjustment for radon exposure. In addition to applying three DEE exposure estimates developed by DEMS, we applied six alternative estimates. Without adjusting for radon, our results were similar to those in the original DEMS analysis: all but one of the nine DEE exposure estimates showed evidence of an association between DEE exposure and lung cancer mortality, with trend slopes differing only by about a factor of two. When exposure to radon was adjusted, the evidence for a DEE effect was greatly diminished, but was still present in some analyses that utilized the three original DEMS DEE exposure estimates. A DEE effect was not observed when the six alternative DEE exposure estimates were utilized and radon was adjusted. No consistent evidence of a DEE effect was found among miners who worked only underground. This article highlights some issues that should be addressed in any use of the DEMS data in developing a QRA for DEE. PMID:25857246

  10. Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM): A Year 2000 Global Baseline for Measuring Topographic Change

    NASA Astrophysics Data System (ADS)

    Crippen, R. E.

    2002-12-01

    The SRTM DEM is the first near-global, high-resolution elevation model. The data were acquired in February 2000 aboard the Space Shuttle Endeavour and cover the Earth's land masses between 60N and 56S latitudes at about 30 meters spatial resolution. The data are a virtual global snapshot in that they were acquired in about 10 days by a single sensor. Absolute vertical accuracy was targeted at 16 meters. However, spatially broad temporal changes in topography have been detected and measured down to about one-meter precision by comparing the SRTM DEM to the USGS National Elevation Dataset (NED). NED has similar spatial properties, but was independently derived, commonly years (or decades) earlier. Such changes already noted include those related to volcanic processes, alluvial fan deposition, subsidence related to oil extraction, and direct anthropogenic changes such as landfills and major road cuts and fills. Large tectonic changes in topography are likewise potentially evident in such comparisons. New and forthcoming satellites include capabilities to produce elevation models that can be used to detect and measure ongoing and future topographic change when compared to the SRTM DEM. For example, the ASTER instrument on the Terra satellite (launched in 1999) produces targeted DEMs, and SPOT-5 (launched in 2002) is expected to produce a global DEM over a five-year period. Both of these DEM sources (and the NED and others) use optical wavelength sensors which may "observe a different surface" than the SRTM radar, particularly in heavily vegetated areas, and this must be considered in making the comparisons. However, having a "before" data set is often the roadblock in measuring change, and SRTM has now provided the first detailed "before" DEM for most of Earth's land surface.

  11. DEM L241, A SUPERNOVA REMNANT CONTAINING A HIGH-MASS X-RAY BINARY

    SciTech Connect

    Seward, F. D.; Charles, P. A.; Foster, D. L.; Dickel, J. R.; Romero, P. S.; Edwards, Z. I.; Perry, M.; Williams, R. M.

    2012-11-10

    A Chandra observation of the Large Magellanic Cloud supernova remnant DEM L241 reveals an interior unresolved source which is probably an accretion-powered binary. The optical counterpart is an O5III(f) star making this a high-mass X-ray binary with an orbital period likely to be of the order of tens of days. Emission from the remnant interior is thermal and spectral information is used to derive density and mass of the hot material. Elongation of the remnant is unusual and possible causes of this are discussed. The precursor star probably had mass >25 M {sub Sun}.

  12. THE H{alpha} DIAGNOSTIC OF ELECTRON HEATING: THE CASE OF DEM L71

    SciTech Connect

    Rakowski, Cara E.; Ghavamian, Parviz; Laming, J. Martin

    2009-05-10

    Recently, the mechanisms and extent of immediate postshock heating of electrons at collisionless shocks have been under intense investigation. Several recent studies have suggested that the ratio of electron to proton temperature at the shock front scales approximately as the inverse square of the shock velocity. A specific interpretation of this dependence was first introduced by Ghavamian et al., who suggested electron heating by lower-hybrid waves in a cosmic ray (CR) precursor as a possible mechanism behind such a relationship. The best line diagnostics for the electron to proton temperature ratio behind collisionless shocks in partially neutral gas are the combination of broad and narrow H{alpha} lines emitted in the immediate vicinity of the shock front. In this work, we present extensive long-slit spectroscopy of the H{alpha} emission in the blast wave shock of supernova remnant DEM L71. We chose this remnant for two main reasons. First, the shock velocities in DEM L71 span the range of speeds where the electron to proton temperature ratio varies most rapidly with shock speed. Second, previous Fabry-Perot scans of the H{alpha} line complex indicated broad-to-narrow flux ratios lower than existing models predicted, but the spectral coverage of those observations was not broad enough to reliably measure the background emission around the broad component H{alpha} line. Our new high-resolution (R {approx}> 1600) spectra of DEM L71 provide extensive coverage of the background near the H{alpha} line and confirm our earlier Fabry-Perot results of consistently low ({approx}<1) broad-to-narrow flux ratios. Here, we present results of these observations and also outline the first results from spectra of radiative portions of DEM L71. We compare our results to the latest models of H{alpha} profiles from collisionless shocks. We conclude that the most likely explanation for the low broad-to-narrow flux ratio is the ionization and excitation of neutrals by electrons

  13. Tropical-Forest Biomass Dynamics from X-Band, TanDEM-X DATA

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Neumann, M.; Keller, M. M.; Goncalves, F. G.; Santos, J. R.

    2015-12-01

    The measurement of the change in above ground biomass (AGB) is key for understanding the carbon sink/source nature of tropical forests. Interferometric X-band radar from the only orbiting interferometer, TanDEM-X, shows sensitivity to standing biomass up to at least 300 Mg/ha. This sensitivity may be due in part to the propagation of the shorter X-band wavelength (0.031 m) through holes in the canopy. This talk focuses on estimating the change in AGB over time. Interferometric baselines from TanDEM-X have been obtained in Tapajós National Forest in the Brazilian Amazon over a 4-year period, from 2011 to 2015. Lidar measurements were also acquired during this period. Field measurements of height, height-to-base-of-crown, species, diameter, and position were acquired in 2010, 2013, and 2015. We show interferometric phase height changes, and suggest how these phase height changes are related to biomass change. First we show height changes between baselines separated by one month, over which we expect no change in AGB, to evaluate precision. We find an RMS of <2 m for ~85 stands in the phase height over one month, corresponding to about a 10% measurement of change, which suggests we can detect about a 17 Mg/ha change in AGB at Tapajos. In contrast, interferometric height changes over the period 2011 to 2014 have larger RMS scatters of > 3 m, due to actual change. Most stands show changes in interferometric phase height consistent with regrowth (~10 Mg/ha/yr), and several stands show abrupt, large changes in phase height (>10 m) due to logging and natural disturbance. At the end of 2015, we will acquire more TanDEM-X data over Tapajos, including an area subjected to selective logging. We are doing "before" (March 2015) and "after" (October 2015) fieldwork to be able to understand the signature of change due to selective logging in TanDEM-X interferometric data.

  14. Investigation of micro-structural phenomena at aggregate level in concretes using DEM

    NASA Astrophysics Data System (ADS)

    Nitka, Michał; Tejchman, Jacek

    2017-06-01

    This paper presents numerical analyses of concrete beams under three-point bending. The discrete element methods (DEM) was used to calculate fracture at the aggregate level. Concrete was described as a four-phase material, which was composed of aggregate, cement matrix, interfacial transitional zones (ITZs) and macro-voids. The beam micro-structure was directly taken from our experiments using x-ray micro-tomography. Simulations were carried out with real aggregate modelled as sphere clusters. Numerical results were compared with laboratory outcomes. The special attention was laid on the fracture propagation and some micro-structural phenomena at the aggregate level.

  15. Analysis of compaction of railway ballast by different maintenance methods using DEM

    NASA Astrophysics Data System (ADS)

    Ferellec, Jean-Francois; Perales, Robert; Nhu, Viet-Hung; Wone, Michel; Saussine, Gilles

    2017-06-01

    Railway traffic continuously increasing, ballasted tracks need more efficient maintenance processes. Lines with long welded rails which are prone to buckling during heat waves require stabilisation before being fully operational. Stabilisation is performed either naturally using regular traffic at penalising lower speeds, dynamic stabilisation of sleepers or alternatively crib compaction. The objective of this paper is to apply the NSCD approach of DEM to simulate the processes of dynamic stabilisation and crib compaction as they are realised on site and compare their performance in terms of ballast compaction and lateral resistance. The results showed that NSCD is perfectly appropriate to simulate these maintenance processes and estimate their performance.

  16. Temporal monitoring of Bardarbunga volcanic activity with TanDEM-X

    NASA Astrophysics Data System (ADS)

    Rossi, C.; Minet, C.; Fritz, T.; Eineder, M.; Erten, E.

    2015-12-01

    On August 29, 2014, a volcanic activity started in the lava field of Holuhraun, at the north east of the Bardarbunga caldera in Iceland. The activity was declared finished on February 27, 2015, thus lasting for about 6 months. During these months the magma chamber below the caldera slowly emptied, causing the rare event of caldera collapse. In this scenario, TanDEM-X remote sensing data is of particular interest. By producing high-resolution and accurate elevation models of the caldera, it is possible to evaluate volume losses and topographical changes useful to increase the knowledge about the volcanic activity dynamics. 5 TanDEM-X InSAR acquisitions have been commanded between August 01, 2014 and November 08, 2014. 2 acquisitions have been commanded before the eruption and 3 acquisitions afterwards. To fully cover the volcanic activity, also the lava flow area at the north-west of the caldera has been monitored and a couple of acquisitions have been employed to reveal the subglacial graben structure and the lava path. In this context, the expected elevation accuracy is studied on two levels. Absolute height accuracy is analyzed by inspecting the signal propagation at X-band in the imaged medium. Relative height accuracy is analyzed by investigating the InSAR system parameters and the local geomorphology. It is shown how the system is very well accurate with mean height errors below the meter. Moreover, neither InSAR processing issues, e.g. phase unwrapping errors, nor complex DEM calibration aspects are problems to tackle. Caldera is imaged in its entirety and new cauldron formations and, in general, the complete restructuring of the glacial volcanic system is well represented. An impressive caldera volume loss of about 1 billion cubic meters is measured in about two months. The dyke propagation from the Bardarbunga cauldron to the Holuhraun lava field is also revealed and a graben structure with a width of up to 1 km and a sinking of a few meters is derived

  17. Der Kalte Krieg in der Peripherie Griechische Physiker und Atomenergie nach dem Zweiten Weltkrieg

    NASA Astrophysics Data System (ADS)

    Vlahakis, George N.

    Die vorliegende Arbeit analysiert Ansichten griechischer Physiker zur Atomenergie und deren mögliche Anwendung nach dem Zweiten Weltkrieg, insbesondere während des Kalten Kriegs. Einerseits werden Ansichten von Physik- Professoren griechischer Universitäten präsentiert - beispielsweise von Dimitrios Hondros, der Student von Arnold Sommerfeld und Mitarbeiter von Peter Debye in München war, und andererseits wird die Politik der griechischen Regierung für die Etablierung eines Forschungsinstitutes diskutiert, das der Entwicklung der Atomenergie dienen sollte; ebenfalls wird eine öffentliche Meinungsumfrage zu diesen Thema, die in den Tageszeitungen der damaligen Zeit präsentiert wurde, diskutiert.

  18. Evaluation of TanDEM-X elevation data for geomorphological mapping and interpretation in high mountain environments - A case study from SE Tibet, China

    NASA Astrophysics Data System (ADS)

    Pipaud, Isabel; Loibl, David; Lehmkuhl, Frank

    2015-10-01

    Digital elevation models (DEMs) are a prerequisite for many different applications in the field of geomorphology. In this context, the two near-global medium resolution DEMs originating from the SRTM and ASTER missions are widely used. For detailed geomorphological studies, particularly in high mountain environments, these datasets are, however, known to have substantial disadvantages beyond their posting, i.e., data gaps and miscellaneous artifacts. The upcoming TanDEM-X DEM is a promising candidate to improve this situation by application of state-of-the-art radar technology, exhibiting a posting of 12 m and less proneness to errors. In this study, we present a DEM processed from a single TanDEM-X CoSSC scene, covering a study area in the extreme relief of the eastern Nyainqêntanglha Range, southeastern Tibet. The potential of the resulting experimental TanDEM-X DEM for geomorphological applications was evaluated by geomorphometric analyses and an assessment of landform cognoscibility and artifacts in comparison to the ASTER GDEM and the recently released SRTM 1″ DEM. Detailed geomorphological mapping was conducted for four selected core study areas in a manual approach, based exclusively on the TanDEM-X DEM and its basic derivates. The results show that the self-processed TanDEM-X DEM yields a detailed and widely consistent landscape representation. It thus fosters geomorphological analysis by visual and quantitative means, allowing delineation of landforms down to footprints of 30 m. Even in this premature state, the TanDEM-X elevation data are widely superior to the ASTER and SRTM datasets, primarily owing to its significantly higher resolution and its lower susceptibility to artifacts that hamper landform interpretation. Conversely, challenges toward interferometric DEM generation were identified, including (i) triangulation facets and missing topographic information resulting from radar layover on steep slopes facing toward the radar sensor, (ii) low

  19. Nanomedical strategy to prolong survival period, heighten cure rate, and lower systemic toxicity of S180 mice treated with MTX/MIT

    PubMed Central

    Song, Ning; Zhao, Ming; Wang, Yuji; Hu, Xi; Wu, Jianhui; Jiang, Xueyun; Li, Shan; Cui, Chunying; Peng, Shiqi

    2016-01-01

    In spite of the usual combination form of methotrexate (MTX)/mitoxantrone (MIT) and various complex combination regimens of MTX/MIT with other anticancer drugs, the survival period, cure rate, and systemic toxicity still need to be improved. For this purpose, a nanostructured amino group-modified mesoporous silica nanoparticles (MSNN)−MTX/MIT was designed. In the preparation, the surface of mesoporous silica nanoparticles (MSNs) was modified with amino groups to form MSNN. The covalent modification of the amino groups on the surface of MSNN with MTX resulted in MSNN−MTX. The loading of MIT into the surface pores of MSNN−MTX produced nanostructured MSNN−MTX/MIT. Compared with the usual combination form (MTX/MIT), nanostructured MSNN−MTX/MIT increased the survival period greatly, heightened the cure rate to a great extent, and lowered the systemic toxicity of the treated S180 mice, significantly. These superior in vivo properties of nanostructured MSNN−MTX/MIT over the usual combination form (MTX/MIT) were correlated with the former selectively releasing MTX and MIT in tumor tissue and inside cancer cells in vitro. The chemical structure and the nanostructure of MSNN−MTX/MIT were characterized using infrared and differential scanning calorimeter spectra as well as transmission electron microscope images, respectively. PMID:27621591

  20. Nanomedical strategy to prolong survival period, heighten cure rate, and lower systemic toxicity of S180 mice treated with MTX/MIT.

    PubMed

    Song, Ning; Zhao, Ming; Wang, Yuji; Hu, Xi; Wu, Jianhui; Jiang, Xueyun; Li, Shan; Cui, Chunying; Peng, Shiqi

    2016-01-01

    In spite of the usual combination form of methotrexate (MTX)/mitoxantrone (MIT) and various complex combination regimens of MTX/MIT with other anticancer drugs, the survival period, cure rate, and systemic toxicity still need to be improved. For this purpose, a nanostructured amino group-modified mesoporous silica nanoparticles (MSNN)-MTX/MIT was designed. In the preparation, the surface of mesoporous silica nanoparticles (MSNs) was modified with amino groups to form MSNN. The covalent modification of the amino groups on the surface of MSNN with MTX resulted in MSNN-MTX. The loading of MIT into the surface pores of MSNN-MTX produced nanostructured MSNN-MTX/MIT. Compared with the usual combination form (MTX/MIT), nanostructured MSNN-MTX/MIT increased the survival period greatly, heightened the cure rate to a great extent, and lowered the systemic toxicity of the treated S180 mice, significantly. These superior in vivo properties of nanostructured MSNN-MTX/MIT over the usual combination form (MTX/MIT) were correlated with the former selectively releasing MTX and MIT in tumor tissue and inside cancer cells in vitro. The chemical structure and the nanostructure of MSNN-MTX/MIT were characterized using infrared and differential scanning calorimeter spectra as well as transmission electron microscope images, respectively.

  1. Finding the service you need: human centered design of a Digital Interactive Social Chart in DEMentia care (DEM-DISC).

    PubMed

    van der Roest, H G; Meiland, F J M; Haaker, T; Reitsma, E; Wils, H; Jonker, C; Dröes, R M

    2008-01-01

    Community dwelling people with dementia and their informal carers experience a lot of problems. In the course of the disease process people with dementia become more dependent on others and professional help is often necessary. Many informal carers and people with dementia experience unmet needs with regard to information on the disease and on the available care and welfare offer, therefore they tend not to utilize the broad spectrum of available care and welfare services. This can have very negative consequences like unsafe situations, social isolation of the person with dementia and overburden of informal carers with consequent increased risk of illness for them. The development of a DEMentia specific Digital Interactive Social Chart (DEM-DISC) may counteract these problems. DEM-DISC is a demand oriented website for people with dementia and their carers, which is easy, accessible and provides users with customized information on healthcare and welfare services. DEM-DISC is developed according to the human centered design principles, this means that people with dementia, informal carers and healthcare professionals were involved throughout the development process. This paper describes the development of DEM-DISC from four perspectives, a domain specific content perspective, an ICT perspective, a user perspective and an organizational perspective. The aims and most important results from each perspective will be discussed. It is concluded that the human centered design was a valuable method for the development of the DEM-DISC.

  2. Development of high-resolution coastal DEMs: Seamlessly integrating bathymetric and topographic data to support coastal inundation modeling

    NASA Astrophysics Data System (ADS)

    Eakins, B. W.; Taylor, L. A.; Warnken, R. R.; Carignan, K. S.; Sharman, G. F.

    2006-12-01

    The National Geophysical Data Center (NGDC), an office of the National Oceanic and Atmospheric Administration (NOAA), is cooperating with the NOAA Pacific Marine Environmental Laboratory (PMEL), Center for Tsunami Research to develop high-resolution digital elevation models (DEMs) of combined bathymetry and topography. The coastal DEMs will be used as input for the Method of Splitting Tsunami (MOST) model developed by PMEL to simulate tsunami generation, propagation and inundation. The DEMs will also be useful in studies of coastal inundation caused by hurricane storm surge and rainfall flooding, resulting in valuable information for local planners involved in disaster preparedness. We present our methodology for creating the high-resolution coastal DEMs, typically at 1/3 arc-second (10 meters) cell size, from diverse digital datasets collected by numerous methods, in different terrestrial environments, and at various scales and resolutions; one important step is establishing the relationships between various tidal and geodetic vertical datums, which may vary over a gridding region. We also discuss problems encountered and lessons learned, using the Myrtle Beach, South Carolina DEM as an example.

  3. Comparison of elevation derived from insar data with dem from topography map in Son Dong, Bac Giang, Viet Nam

    NASA Astrophysics Data System (ADS)

    Nguyen, Duy

    2012-07-01

    Digital Elevation Models (DEMs) are used in many applications in the context of earth sciences such as in topographic mapping, environmental modeling, rainfall-runoff studies, landslide hazard zonation, seismic source modeling, etc. During the last years multitude of scientific applications of Synthetic Aperture Radar Interferometry (InSAR) techniques have evolved. It has been shown that InSAR is an established technique of generating high quality DEMs from space borne and airborne data, and that it has advantages over other methods for the generation of large area DEM. However, the processing of InSAR data is still a challenging task. This paper describes InSAR operational steps and processing chain for DEM generation from Single Look Complex (SLC) SAR data and compare a satellite SAR estimate of surface elevation with a digital elevation model (DEM) from Topography map. The operational steps are performed in three major stages: Data Search, Data Processing, and product Validation. The Data processing stage is further divided into five steps of Data Pre-Processing, Co-registration, Interferogram generation, Phase unwrapping, and Geocoding. The Data processing steps have been tested with ERS 1/2 data using Delft Object-oriented Interferometric (DORIS) InSAR processing software. Results of the outcome of the application of the described processing steps to real data set are presented.

  4. Visualizing impact structures using high-resolution LiDAR-derived DEMs: A case study of two structures in Missouri

    USGS Publications Warehouse

    Finn, Michael P.; Krizanich, Gary W.; Evans, Kevin R.; Cox, Melissa R.; Yamamoto, Kristina H.

    2015-01-01

    Evidence suggests that a crypto-explosive hypothesis and a meteorite impact hypothesis may be partly correct in explaining several anomalous geological features in the middle of the United States. We used a primary geographic information science (GIScience) technique of creating a digital elevation model (DEM) of two of these features that occur in Missouri. The DEMs were derived from airborne light detection and ranging, or LiDAR. Using these DEMs, we characterized the Crooked Creek structure in southern Crawford County and the Weaubleau structure in southeastern St. Clair County, Missouri. The mensuration and study of exposed and buried impact craters implies that the craters may have intrinsic dimensions which could only be produced by collision. The results show elevations varying between 276 and 348 m for Crooked Creek and between 220 and 290 m for Weaubleau structure. These new high- resolution DEMs are accurate enough to allow for precise measurements and better interpretations of geological structures, particularly jointing in the carbonate rocks, and they show greater definition of the central uplift area in the Weaubleau structure than publicly available DEMs.

  5. Arctic Digital Elevation Models (DEMs) generated by Surface Extraction from TIN-Based Searchspace Minimization (SETSM) algorithm from RPCs-based Imagery

    NASA Astrophysics Data System (ADS)

    Noh, M. J.; Howat, I. M.; Porter, C. C.; Willis, M. J.; Morin, P. J.

    2016-12-01

    The Arctic is undergoing rapid change associated with climate warming. Digital Elevation Models (DEMs) provide critical information for change measurement and infrastructure planning in this vulnerable region, yet the existing quality and coverage of DEMs in the Arctic is poor. Low contrast and repeatedly-textured surfaces, such as snow and glacial ice and mountain shadows, all common in the Arctic, challenge existing stereo-photogrammetric techniques. Submeter resolution, stereoscopic satellite imagery with high geometric and radiometric quality, and wide spatial coverage are becoming increasingly accessible to the scientific community. To utilize these imagery for extracting DEMs at a large scale over glaciated and high latitude regions we developed the Surface Extraction from TIN-based Searchspace Minimization (SETSM) algorithm. SETSM is fully automatic (i.e. no search parameter settings are needed) and uses only the satellite rational polynomial coefficients (RPCs). Using SETSM, we have generated a large number of DEMs (> 100,000 scene pair) from WorldView, GeoEye and QuickBird stereo images collected by DigitalGlobe Inc. and archived by the Polar Geospatial Center (PGC) at the University of Minnesota through an academic licensing program maintained by the US National Geospatial-Intelligence Agency (NGA). SETSM is the primary DEM generation software for the US National Science Foundation's ArcticDEM program, with the objective of generating high resolution (2-8m) topography for the entire Arctic landmass, including seamless DEM mosaics and repeat DEM strips for change detection. ArcticDEM is collaboration between multiple US universities, governmental agencies and private companies, as well as international partners assisting with quality control and registration. ArcticDEM is being produced using the petascale Blue Waters supercomputer at the National Center for Supercomputer Applications at the University of Illinois. In this paper, we introduce the SETSM

  6. Mapping of jog locus to the region between D6Mit104 and D6Mit336 on mouse chromosome 6.

    PubMed

    Sun, Xiao-yang; Chen, Zi-yan; Kanou, Yasuhiko; Takagishi, Yoshiko; Hayashi, Yoshitaka; Ohno, Tamio; Murata, Yoshiharu; Oda, Sen-ichi

    2007-10-01

    The joggle mouse is a recessive ataxic mutant carrying an unknown mutation in a C3H/He (C3H)-derived chromosomal segment. Taking advantage of the mouse genome database, we selected 127 DNA microsatellite markers showing heterozygosity between C3H and C57BL/6J (B6) and a first round of screening for the joggle mutation was performed on B6-jog/+ partial congenic mice (N4). We identified 4 chromosomal regions in which 13 microsatellite markers show heterozygosity between C3H and B6. Then, we analyzed the genotype of these 4 chromosomal regions in mice that showed the joggle phenotype and mapped the jog locus between markers D6Mit104 (111.4 Mb) and D6Mit336 (125.1 Mb) (an interval of 13.7 Mb) on chromosome 6. By using a partial congenic strain together with the mouse genome database, we successfully mapped the chromosomal localization of the jog locus much more efficiently than by conventional linkage analysis.

  7. DEM study of fabric features governing undrained post-liquefaction shear deformation of sand

    DOE PAGES

    Wang, Rui; Fu, Pengcheng; Zhang, Jian-Min; ...

    2016-10-05

    In an effort to study undrained post-liquefaction shear deformation of sand, the discrete element method (DEM) is adopted to conduct undrained cyclic biaxial compression simulations on granular assemblies consisting of 2D circular particles. The simulations are able to successfully reproduce the generation and eventual saturation of shear strain through the series of liquefaction states that the material experiences during cyclic loading after the initial liquefaction. Also, DEM simulations with different deviatoric stress amplitudes and initial mean effective stresses on samples with different void ratios and loading histories are carried out to investigate the relationship between various mechanics- or fabric-related variablesmore » and post-liquefaction shear strain development. It is found that well-known metrics such as deviatoric stress amplitude, initial mean effective stress, void ratio, contact normal fabric anisotropy intensity, and coordination number, are not adequately correlated to the observed shear strain development and, therefore, could not possibly be used for its prediction. A new fabric entity, namely the Mean Neighboring Particle Distance (MNPD), is introduced to reflect the space arrangement of particles. It is found that the MNPD has an extremely strong and definitive relationship with the post-liquefaction shear strain development, showing MNPD’s potential role as a parameter governing post-liquefaction behavior of sand.« less

  8. Tectonic development of the Northwest Bonaparte Basin, Australia by using Digital Elevation Model (DEM)

    NASA Astrophysics Data System (ADS)

    Wahid, Ali; Salim, Ahmed Mohamed Ahmed; Ragab Gaafar, Gamal; Yusoff, AP Wan Ismail Wan

    2016-02-01

    The Bonaparte Basin consist of majorly offshore part is situated at Australia's NW continental margin, covers an area of approx. 270,000km2. Bonaparte Basin having a number of sub-basins and platform areas of Paleozoic and Mesozoic is structurally complex. This research established the geologic and geomorphologic studies using Digital Elevation Model (DEM) as a substitute approach in morphostructural analysis to unravel the geological complexities. Although DEMs have been in practice since 1990s, they still have not become common tool for mapping studies. The research work comprised of regional structural analysis with the help of integrated elevation data, satellite imageries, available open topograhic images and internal geological maps with interpreted seismic. The structural maps of the study area have been geo-referenced which further overlaid onto SRTM data and satellite images for combined interpretation which facilitate to attain Digital Elevation Model of the study area. The methodology adopts is to evaluate and redefine development of geodynamic processes involved in formation of Bonaparte Basin. The main objectives is to establish the geological histories by using digital elevation model. The research work will be useful to incorporate different tectonic events occurred at different Geological times in a digital elevation model. The integrated tectonic analysis of different digital data sets benefitted substantially from combining them into a common digital database. Whereas, the visualization software facilitates the overlay and combined interpretation of different data sets which is helpful to reveal hidden information not obvious or accessible otherwise for regional analysis.

  9. Hydrological modeling using high resolution dem to level control on highways

    NASA Astrophysics Data System (ADS)

    Akbulut, Zeynep; Cömert, Çetin

    2016-04-01

    Floods are natural disasters that must be managed, controlled and taken precautions before it happens considering the damage they inflicted to environment and human lives. As to highways, the main vein of urban life flow, must be taken into consideration as a different entity that affected by excessive rainfalls and floods. Due to inadequate drainage that allow rainfall to form water ponds on highways cause vehicles to lose control and that lead vehicles to have traffic accidents. To reduce the traffic accidents caused by ponding waters on highways we need to know area of inundation and water depths. In this context we used FLO-2D Basic Model (2009) to hydrological modeling of Black Sea Coastal Highway with meteorological and hydrological data using a Digital Elevation Model (DEM). In this study, ponding areas on highways determined by simulating the rainfall with a high resolution DEM that can represent the actual road surface correctly. With this information, General Directorate of Highways (GDH) in Turkey can adjust the cross-sectional and longitudinal slope or build better and bigger drainage structures where water accumulated to prevent ponding. With the results obtained from Hydrological Model, GDH can rapidly control highways conformity to regulations before highways come into service. Also these ponding areas acquired by reveals where to prioritize in flood risk managements. Key Words: Area of Inundation, Digital Elevation Model, FLO-2D, Hydrological Modeling, Highway, Rainfall-Runoff Simulation, Water Depth.

  10. A Method for Improving SRTM DEMs in High-Relief Terrain

    NASA Astrophysics Data System (ADS)

    Falorni, G.; Istanbulluoglu, E.; Bras, R. L.

    2003-12-01

    The Shuttle Radar Topography Mission (SRTM) had the objective of mapping the Earth's surface between 56 o S and 60 o N to produce the first near-global high resolution digital elevation model (DEM). The dataset, with a horizontal resolution of 1 arc second ( ˜ 30 m), has now been released for the conterminous U.S. Recent investigations aimed at assessing the vertical accuracy of the dataset have revealed that elevation accuracy is well within dataset specifications in areas of low- to modest-relief but that errors generally increase in high-relief terrains. Statistical analyses performed with the objective of characterizing the error structure in two study sites within the U.S. have highlighted the existence of correlations between elevation residuals and slope gradient, slope bearing and elevation. In particular, the analyses show that the largest errors occur on steep slopes and that slope bearing has a marked influence on the sign of the elevation residuals. Based on these findings we are currently investigating a method for correcting relevant vertical errors in SRTM-derived DEMs according to their topographic location. We propose to use a combination of indices derived from the statistical analyses to predict the occurrence, magnitude and sign of the vertical errors.

  11. Open-Source MFIX-DEM Software for Gas-Solids Flows: Part II - Validation Studies

    SciTech Connect

    Li, Tingwen

    2012-04-01

    With rapid advancements in computer hardware and numerical algorithms, computational fluid dynamics (CFD) has been increasingly employed as a useful tool for investigating the complex hydrodynamics inherent in multiphase flows. An important step during the development of a CFD model and prior to its application is conducting careful and comprehensive verification and validation studies. Accordingly, efforts to verify and validate the open-source MFIX-DEM software, which can be used for simulating the gas–solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles, have been made at the National Energy Technology Laboratory (NETL). In part I of this paper, extensive verification studies were presented and in this part, detailed validation studies of MFIX-DEM are presented. A series of test cases covering a range of gas–solids flow applications were conducted. In particular the numerical results for the random packing of a binary particle mixture, the repose angle of a sandpile formed during a side charge process, velocity, granular temperature, and voidage profiles from a bounded granular shear flow, lateral voidage and velocity profiles from a monodisperse bubbling fluidized bed, lateral velocity profiles from a spouted bed, and the dynamics of segregation of a binary mixture in a bubbling bed were compared with available experimental data, and in some instances with empirical correlations. In addition, sensitivity studies were conducted for various parameters to quantify the error in the numerical simulation.

  12. Open-source MFIX-DEM software for gas-solids flows: Part II Validation studies

    SciTech Connect

    Li, Tingwen; Garg, Rahul; Galvin, Janine; Pannala, Sreekanth

    2012-01-01

    With rapid advancements in computer hardware and numerical algorithms, computational fluid dynamics (CFD) has been increasingly employed as a useful tool for investigating the complex hydrodynamics inherent in multiphase flows. An important step during the development of a CFD model and prior to its application is conducting careful and comprehensive verification and validation studies. Accordingly, efforts to verify and validate the open-source MFIX-DEM software, which can be used for simulating the gas solids flow using an Eulerian reference frame for the continuum fluid and a Lagrangian discrete framework (Discrete Element Method) for the particles, have been made at the National Energy Technology Laboratory (NETL). In part I of this paper, extensive verification studies were presented and in this part, detailed validation studies of MFIX-DEM are presented. A series of test cases covering a range of gas solids flow applications were conducted. In particular the numerical results for the random packing of a binary particle mixture, the repose angle of a sandpile formed during a side charge process, velocity, granular temperature, and voidage profiles from a bounded granular shear flow, lateral voidage and velocity profiles from a monodisperse bubbling fluidized bed, lateral velocity profiles from a spouted bed, and the dynamics of segregation of a binary mixture in a bubbling bed were compared with available experimental data, and in some instances with empirical correlations. In addition, sensitivity studies were conducted for various parameters to quantify the error in the numerical simulation.

  13. TanDEM-X Across-Track Interferometry over Dry Snow Covered Terrain

    NASA Astrophysics Data System (ADS)

    Panagiotopoulou, Dimitra; Brown, Ian A.

    2016-08-01

    We analyse bistatic HH-polarised TanDEM-X interferometric synthetic aperture radar (InSAR) data acquired over winter, dry snow conditions in a sub- Arctic site in Norway. Exploiting the principles of across-track interferometry, the elevation of the scattering phase centre estimated by the phase difference between the two SAR acquisitions. Interference patterns were assessed both qualitatively and quantitatively. Clearings and forest stands, were analysed. Interferometric phase uncertainty and spatio-temporal consistency were analysed by means of scattering phase centre elevation accuracy and coherence degree, γ with respect to hydro-meteorological conditions. Clearings displayed absolute height errors of < 1 m. The sole approximation was to consider volume decorrelation effects as main source of elevation ambiguities and coherence decay. Principal Component Analysis was conducted to identify the combined influence of variables describing the radar response and scattering centre. However, the derived DEMs attained high vertical accuracy, the sub-meter height errors might relate to snowcover effects. Coherence was strongly influenced by snowpack parameters suggesting TDM coherence inversion may enable snow cover monitoring.

  14. Improved TanDEM-X forest height estimation assisted by simulated GEDI lidar canopy height

    NASA Astrophysics Data System (ADS)

    Qi, W.; Dubayah, R.; Lee, S. K.

    2016-12-01

    TanDEM-X (TDX) simultaneous InSAR acquisitions enable observations of forest structure from space without temporal decorrelation effect that exists in traditional repeat-pass SAR missions. Exploring the capability of globally-available single-polarized TDX data in forest height estimation helps to realize large-scale quantification of forest structure and the associated biomass. However, sub-optimal performance in height estimates were found using the single-pol InSAR data when a high-resolution digital terrain model (DTM) was not available and a comprise was made by assuming a fixed extinction coefficient in the widely used forest scattering model - the Random Volume over Ground (RVoG) model. The goal of this paper is to address this issue by incorporating data to be collected from NASA's next-generation spaceborne full-waveform lidar mission - Global Ecosystem Dynamics Investigation (GEDI) to improve the TanDEM-X height estimates. More specifically, we investigated the efficacy of using tracks of elevation and canopy height measurements from simulation of GEDI data to improve the performance of the RVoG model in a mixed temperate forest. Results showed that the bias of RVoG height estimation can be greatly reduced from 2.5m without any lidar input to 1.8m using only simulated GEDI elevation and further to 0.5m when both elevation and canopy height from simulated GEDI data were exploited.

  15. Improvement of dem Generation from Aster Images Using Satellite Jitter Estimation and Open Source Implementation

    NASA Astrophysics Data System (ADS)

    Girod, L.; Nuth, C.; Kääb, A.

    2015-12-01

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) system embarked on the Terra (EOS AM-1) satellite has been a source of stereoscopic images covering the whole globe at a 15m resolution at a consistent quality for over 15 years. The potential of this data in terms of geomorphological analysis and change detection in three dimensions is unrivaled and needs to be exploited. However, the quality of the DEMs and ortho-images currently delivered by NASA (ASTER DMO products) is often of insufficient quality for a number of applications such as mountain glacier mass balance. For this study, the use of Ground Control Points (GCPs) or of other ground truth was rejected due to the global "big data" type of processing that we hope to perform on the ASTER archive. We have therefore developed a tool to compute Rational Polynomial Coefficient (RPC) models from the ASTER metadata and a method improving the quality of the matching by identifying and correcting jitter induced cross-track parallax errors. Our method outputs more accurate DEMs with less unmatched areas and reduced overall noise. The algorithms were implemented in the open source photogrammetric library and software suite MicMac.

  16. Calibration of micromechanical parameters for DEM simulations by using the particle filter

    NASA Astrophysics Data System (ADS)

    Cheng, Hongyang; Shuku, Takayuki; Thoeni, Klaus; Yamamoto, Haruyuki

    2017-06-01

    The calibration of DEM models is typically accomplished by trail and error. However, the procedure lacks of objectivity and has several uncertainties. To deal with these issues, the particle filter is employed as a novel approach to calibrate DEM models of granular soils. The posterior probability distribution of the microparameters that give numerical results in good agreement with the experimental response of a Toyoura sand specimen is approximated by independent model trajectories, referred as `particles', based on Monte Carlo sampling. The soil specimen is modeled by polydisperse packings with different numbers of spherical grains. Prepared in `stress-free' states, the packings are subjected to triaxial quasistatic loading. Given the experimental data, the posterior probability distribution is incrementally updated, until convergence is reached. The resulting `particles' with higher weights are identified as the calibration results. The evolutions of the weighted averages and posterior probability distribution of the micro-parameters are plotted to show the advantage of using a particle filter, i.e., multiple solutions are identified for each parameter with known probabilities of reproducing the experimental response.

  17. Assessing volume change of tropical Peruvian glaciers from multi-temporal digital elevation models (DEMs)

    NASA Astrophysics Data System (ADS)

    Huh, K.; Mark, B. G.

    2012-12-01

    Although far smaller than large polar ice caps, mountain glaciers are significant contributors to sea level rise and tropical glaciers in particular are sources of critical water resources to regional societies. The glaciers in Cordillera Blanca, the Andes of Peru, hold important environmental and economic concerns of regional water supplies to communities in the arid western part of the country under continued global climate change. Yet steep relief and remote locations present challenges for measuring mass changes in tropical glaciers. Remotely sensed images provide feasible opportunities to measure glacier surface area changes. We use a combination of satellite and airborne remote sensing, digital photogrammetry and geospatial techniques to assess the surface area, volume and topographic changes of key glaciers in the Cordillera Blanca, Peru between 1962 and 2008. The intercomparison of digital elevation models (DEMs) from airborne Light Detection and Range (LiDAR) data of 2008, multispectral Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) of 2001-2008 and stereo-paired airborne photographs of 1962 for deriving elevation differences over time reveal the data quality to measure the volume loss in the area. The DEMs over non-glacier areas in the study sites were selected and differentially corrected Global Positioning System (dGPS) data points were used for comparison as well. The motivation of this study is to refine a surface area to volume scaling for tropical glaciers to enable extrapolation of more detailed inventory of glacier volume and water resources.

  18. Constructing Palaeo-DEMs in landscape evolution: example of the Geren catchment, Turkey

    NASA Astrophysics Data System (ADS)

    van Gorp, Wouter; Schoorl, Jeroen M.; Veldkamp, Tom; Maddy, Darrel; Demir, Tuncer; Aytac, Serdar

    2017-04-01

    How to reconstruct the past landscape and how does this influence your modelling results? This is an important paradigma in the soilscape and landscape evolution modelling community. Here an example of Turkey will be presented where a 300 ka LEM simulation requested to the thoroughly think about the initial landscape as an important input. What information can be used to know the morphology of a landscape 300 ka ago? The Geren catchment, a tributary of the upstream Gediz river near Kula, Turkey, has been influenced by base level changes during the Late Pleistocene and Holocene. Different lavaflows have blocked the Gediz and Geren river several times over in the timespan of the last 300 ka -200 Ka and in the recent Holocene. The heavily dissected Geren catchment shows a landscape evolution which is more complex than just a reaction on these base level changes. The steps and inputs of the palaeo DEM reconstruction will be presented and the modelling results will be presented. Keywords: Digital Elevation Model, Palaeo DEMs, Numerical modelling

  19. A hybrid DEM-SPH model for deformable landslide and its generated surge waves

    NASA Astrophysics Data System (ADS)

    Tan, Hai; Chen, Shenghong

    2017-10-01

    Reservoir bank landslide and its generated surge waves are catastrophic hazards which may give rise to additional sedimentation, destroy hydraulic structures, and even cause fatalities. Since this process is very complex involving landslide impact, wave generation and propagation, it cannot be well captured with traditional numerical approaches. In this paper, a hybrid DEM-SPH model is presented to simulate landslide and to reproduce its generated surge waves. This model consists of discrete element method (DEM) for solid phase and smoothed particle hydrodynamics (SPH) for fluid phase as well as drag force and buoyancy for solid-fluid interaction. Meanwhile, the δ-SPH algorithm is employed to eliminate spurious numerical noise on the pressure field. Submarine rigid block slide is numerically tested to validate the proposed hybrid model, and the computed wave profiles exhibit a satisfactory agreement with the experiment. The hybrid model is further extended towards the submarine granular deformable slide which generates smaller and less violent surge waves. Kinetic and potential energy of both solid and fluid particle system are extracted to throw a light upon the process of landslide water interaction from an energy perspective. Finally, a sensitivity analysis on particle friction coefficient indicates that the lubrication of the solid particles is another important effect influencing the underwater landslide movement in addition to the drag effect.

  20. A spheropolygonal-based DEM study into breakage under repetitive compression

    NASA Astrophysics Data System (ADS)

    Miao, Guien; Alonso-Marroquin, Fernando; Airey, David

    2017-06-01

    Experimental breakage studies have often focused on comparing grading and particle shape data from the beginning and end of a test, but one major advantage of DEM simulations is that, although the data are still discrete, more information on intermediate stages is available. This paper describes a repetitive compression test using a 2D aggregate-based DEM model comprised of spheropolygonal particles (formed by the Minkowski sum of a circle and a polygon, viz. sweeping a circle around the edges of the polygon) that are connected by beams and compares the behaviour with experimental data on the breakage of Barrys Beach carbonate sand. The one-dimensional repetitive compression test was performed on 20 particles—each consisting of over 100 sub-particles—which were generated from the outlines of particles of Barrys Beach carbonate sand. Particle breakage was described through the breakage of beams (particle bonds), allowing the evaluation of changes in the compressibility and grading. It was noted that the simulation compared well with the experimental behaviour of Barrys Beach carbonate sand.

  1. 3D DEM study of stick-slip behavior in partly saturated granular materials

    NASA Astrophysics Data System (ADS)

    Dorostkar, Omid; Johnson, Paul; Guyer, Robert; Marone, Chris; Carmeliet, Jan

    2017-04-01

    In the central part of faults, granular material is produced due to wear called fault gouge. During shearing, the fault gouge stores energy in the course of the stick phase, which can be suddenly released resulting in a stick-slip dynamics. The sudden release of accumulated energy leads to a drop in macroscopic friction coefficient, defined as ratio between shear stress and confining stress and to a sudden increase in kinetic energy of particles. Partial saturation of granular fault gouge with water can alter this dynamic stick-slip behavior. We use 3D discrete element method (DEM) simulations to study stick-slip dynamics in a wet granular fault gouge. The DEM model takes the presence of moisture into account introducing cohesive forces due to the presence of capillary bridges between the particles. We also consider viscous forces resistant to particles motion. Results show that in wet granular gouge, the macroscopic friction level attained during shearing is higher than in the dry state. The cohesive forces due to surface tension and Laplace pressure tend to maintain the contacts longer leading to longer and more stable stick phases, or higher recurrence times between successive slip events. This means that more energy can be stored leading to larger slip events characterized by larger drops in friction coefficient and larger thickness compaction. Our results are in line with experimental results on granular gouge of glass beads.

  2. A knowledge-based, two-step procedure for extracting channel networks from noisy dem data

    NASA Astrophysics Data System (ADS)

    Smith, Terence R.; Zhan, Cixiang; Gao, Peng

    We present a new procedure for extracting channel networks from noisy DEM data. The procedure is a knowledge-based, two-step procedure employing both local and nonlocal information. In particular, we employ a model of an ideal drainage network as a source of constraints that must be satisfied by the output of the procedure. We embed these constraints as part of the network extraction procedure. In a first step, the procedure employs the facet model of Haralick to extract valley information from digital images. The constraints employed at this stage relate to conditions indicating reliable valley pixels. In a second step, the procedure applies knowledge of drainage networks to integrate reliable valley points discovered into a network of single-pixel width lines. This network satisfies the constraints imposed by viewing a drainage network as a binary tree in which the channel segments have a one-pixel width. The procedure performs well on DEM data in the example investigated. The overall worst-case performance of the procedure is O( N) log N), but the most computationally intensive step in the procedure is parallelized easily. Hence the procedure is a good candidate for automation.

  3. Region-growing segmentation to automatically delimit synthetic drumlins in 'real' DEMs

    NASA Astrophysics Data System (ADS)

    Eisank, Clemens; Smith, Mike; Hillier, John

    2013-04-01

    Mapping or 'delimiting' landforms is one of geomorphology's primary tools. Computer-based techniques, such as terrain segmentation, may potentially provide terrain units that are close to the size and shape of landforms. Whether terrain units represent landforms heavily depends on the segmentation algorithm, its settings and the type of underlying land-surface parameters (LSPs). We assess a widely used region-growing technique, i.e. the multiresolution segmentation (MRS) algorithm as implemented in object-based image analysis software, for delimiting drumlins. Supervised testing was based on five synthetic DEMs that included the same set of perfectly known drumlins at different locations. This, for the first time, removes subjectivity from the reference data. Five LSPs were tested, and four variants were computed for each using two pre- and post-processing options. The automated method (1) employs MRS to partition the input LSP into 200 ever coarser terrain unit patterns, (2) identifies the spatially best matching terrain unit for each reference drumlin, and (3) computes four accuracy metrics for quantifying the aerial match between delimited and reference drumlins. MRS performed best on LSPs that are regional, derived from a decluttered DEM and then normalized. Median scale parameters (SPs) for segments best delineating drumlins were relatively stable for the same LSP, but varied significantly between LSPs. Larger drumlins were generally delimited at higher SPs. MRS indicated high robustness against variations in the location and distribution of drumlins.

  4. Kinematic structure of the supergiant shell LMC 9 - I. The nebular complex DEM L208

    NASA Astrophysics Data System (ADS)

    Oddone, M. A.; Ambrocio-Cruz, P.; Le Coarer, E.; Goldes, G. V.

    2014-08-01

    This work describes an extensive and eminently observational study, carried out with an Hα filter, of the kinematics of the ionized gas in the large emission region (220 pc) DEM L208 which is located in the south-east part of the Large Magellanic Cloud (LMC). The intention was to establish the region's general kinematic and morphological characteristics, and to analyse its possible association with a larger structure, aiming above all to contribute to the elaboration of a detailed global kinematics image of the LMC. The nebula's edges are well defined, with fairly regular Gaussian profiles, and can be represented by a systemic radial velocity of approximately 250 km s-1 for the brightest area of DEM L208. The radial velocity fields obtained present a main component with a well-defined profile, as well as other weaker components of larger speed, which may be indicative of expansion motion or of another layer of gas. In some regions we find evidence that the disturbance of the medium is due to stellar winds from the interior of the nebula; in others the profiles observed are found to be consistent with very intense stellar winds from Wolf-Rayet stars.

  5. DEM-based Modeling at the Hillslope Scale: Recent Results and Future Process Research Needs

    NASA Astrophysics Data System (ADS)

    McDonnell, J.; Coles, A.; Gabrielli, C. P.; Appels, W. M.; Ameli, A.

    2015-12-01

    Hillslope scale patterns of overland flow, infiltration, subsurface stormflow and groundwater recharge are all topographically mediated. However, the mechanisms by which macro-, meso- and micro-topographies control filling and spilling of lateral flow, and vertical infiltration, are still poorly understood. Here we present high-resolution DEMs derived from ground-based LiDAR, airborne LiDAR, and GPR (ground penetrating rebar!) with model analysis to examine the topographic controls on water flow at three distinct hillslopes. We explore surface topographic effects on rainfall- and snowmelt-infiltration and overland flow on the Canadian Prairies; the surface and subsurface topographic controls on lateral subsurface stormflow generation and groundwater recharge at a steep, wet temperate rainforest in New Zealand; and subsurface topographic controls on patterns of groundwater recharge at a forested hillslope on the Georgia Piedmont in the United States. We demonstrate how these studies reveal future research needs for improving DEM-based watershed delineation and modeling along with some surprising similarities between topographic controls on soil surface infiltration and overland flow and twin subsurface processes at the soil-bedrock interface.

  6. DEM study of granular flow around blocks attached to inclined walls

    NASA Astrophysics Data System (ADS)

    Samsu, Joel; Zhou, Zongyan; Pinson, David; Chew, Sheng

    2017-06-01

    Damage due to intense particle-wall contact in industrial applications can cause severe problems in industries such as mineral processing, mining and metallurgy. Studying the flow dynamics and forces on containing walls can provide valuable feedback for equipment design and optimising operations to prolong the equipment lifetime. Therefore, solids flow-wall interaction phenomena, i.e. induced wall stress and particle flow patterns should be well understood. In this work, discrete element method (DEM) is used to study steady state granular flow in a gravity-fed hopper like geometry with blocks attached to an inclined wall. The effects of different geometries, e.g. different wall angles and spacing between blocks are studied by means of a 3D DEM slot model with periodic boundary conditions. The findings of this work include (i) flow analysis in terms of flow patterns and particle velocities, (ii) force distributions within the model geometry, and (iii) wall stress vs. model height diagrams. The model enables easy transfer of the key findings to other industrial applications handling granular materials.

  7. Potentials of TanDEM-X Interferometric Data for Global Forest/Non-Forest Classification

    NASA Astrophysics Data System (ADS)

    Martone, Michele; Rizzoli, Paola; Brautigam, Benjamin; Krieger, Gerhard

    2016-08-01

    This paper presents a method to generate forest/non- forest maps from TanDEM-X interferometric SAR data. Among the several contributions which may affect the quality of interferometric products, the coherence loss caused by volume scattering represents the contribution which is predominantly affected by the presence of vegetation, and is therefore here exploited as main indicator for forest classification. Due to the strong dependency of the considered InSAR quantity on the geometric acquisition configuration, namely the incidence angle and the interferometric baseline, a multi-fuzzy clustering classification approach is used. Some examples are provided which show the potential of the proposed method. Further, additional features such as urban settlements, water, and critical areas affected by geometrical distortions (e.g. shadow and layover) need to be extracted, and possible approaches are presented as well. Very promising results are shown, which demonstrate the potentials of TanDEM-X bistatic data not only for forest identification, but, more in general, for the generation of a global land classification map as a next step.

  8. A Systems Approach to Healthcare Innovation Using the MIT Hacking Medicine Model.

    PubMed

    Gubin, Tatyana A; Iyer, Hari P; Liew, Shirlene N; Sarma, Aartik; Revelos, Alex; Ribas, João; Movassaghi, Babak; Chu, Zen M; Khalid, Ayesha N; Majmudar, Maulik D; Lee, Christopher Xiang

    2017-07-26

    MIT Hacking Medicine is a student, academic, and community-led organization that uses systems-oriented "healthcare hacking" to address challenges around innovation in healthcare. The group has organized more than 80 events around the world that attract participants with diverse backgrounds. These participants are trained to address clinical needs from the perspective of multiple stakeholders and emphasize utility and implementation viability of proposed solutions. We describe the MIT Hacking Medicine model as a potential method to integrate collaboration and training in rapid innovation techniques into academic medical centers. Built upon a systems approach to healthcare innovation, the time-compressed but expertly guided nature of the events could enable more widely accessible preliminary training in systems-level innovation methodology, as well as creating a structured opportunity for interdisciplinary congregation and collaboration. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Center for Multiscale Plasma Dynamics: Report on Activities (UCLA/MIT), 2009-2010

    SciTech Connect

    Carter, Troy Alan

    2014-10-03

    The final “phaseout” year of the CMPD ended July 2010; a no cost extension was requested until May 2011 in order to enable the MIT subcontract funds to be fully utilized. Research progress over this time included verification and validation activities for the BOUT and BOUT++ code, studies of spontaneous reconnection in the VTF facility at MIT, and studies of the interaction between Alfv´en waves and drift waves in LAPD. The CMPD also hosted the 6th plasma physics winter school in 2010 (jointly with the NSF frontier center the Center for Magnetic Self-Organization, significant funding came from NSF for this most recent iteration of theWinter School).

  10. Rethinking the Relationship Between Academia and Industry: Qualitative Case Studies of MIT and Stanford.

    PubMed

    Zhu, Fengliang; Hawk, Soaring

    2016-10-01

    As knowledge has become more closely tied to economic development, the interrelationship between academia and industry has become stronger. The result has been the emergence of what Slaughter and Leslie call academic capitalism. Inevitably, tensions between academia and industry arise; however, universities such as MIT and Stanford with long traditions of industry interaction have been able to achieve a balance between academic and market values. This paper describes the strategies adopted by MIT and Stanford to achieve this balance. The results indicate that implicit culture is a stronger determinant of balance than are explicit rules. Finally, the author proposes a concept of balance to reconsider the relationship between academia and industry: today's universities, particularly those with strengths in engineering and management, are both symbiotic and interdependent with industry. A reasonable attitude toward the university-industry relationship is that of balance rather than strict separation. Universities can thus establish effective mechanisms to reach a balance between conflicting values.

  11. The MIT Accelerator Laboratory for Diagnostic Development for OMEGA, Z and the NIF

    NASA Astrophysics Data System (ADS)

    Petrasso, R.; Gatu Johnson, M.; Armstrong, E.; Orozco, D.; Rinderknecht, H. G.; Rojas Herrera, J.; Rosenberg, M.; Sio, H.; Zylstra, A.; Frenje, J.; Li, C. K.; Seguin, F. H.; Hahn, K.; Jones, B.; Ruiz, C. L.; Sangster, T. C.

    2014-10-01

    The MIT Linear Electrostatic Ion Accelerator generates D-D and D-3He fusion products, which are used for development of nuclear diagnostics for OMEGA, Z, and the NIF. Fusion reaction rates around 106 s-1 are routinely achieved with this accelerator, and fluence and energy of the fusion products are accurately characterized. Diagnostics developed and calibrated at this facility include CR-39 based charged-particle spectrometers, neutron detectors, and the particle Time-Of-Flight (pTOF) CVD-diamond-based bang time detector. The accelerator is also a vital tool in the education of graduate and undergraduate students at MIT. This work was supported in part by SNL, DOE, LLE and LLNL.

  12. Educational Outreach at the M.I.T. Plasma Fusion Center

    NASA Astrophysics Data System (ADS)

    Censabella, V.

    1996-11-01

    Educational outreach at the MIT Plasma Fusion Center consists of volunteers working together to increase the public's knowledge of fusion and plasma-related experiments. Seeking to generate excitement about science, engineering and mathematics, the PFC holds a number of outreach activities throughout the year, such as Middle and High School Outreach Days. Outreach also includes the Mr. Magnet Program, which uses an interactive strategy to engage elementary school children. Included in this year's presentation will be a new and improved C-MOD Jr, a confinement video game which helps students to discover how computers manipulate magnetic pulses to keep a plasma confined for as long as possible. Also on display will be an educational toy created by the Cambridge Physics Outlet, a PFC spin-off company. The PFC maintains a Home Page on the World Wide Web, which can be reached at http://cmod2.pfc.mit.edu/.

  13. DEM generation from digital photographs using computer vision: Accuracy and application

    NASA Astrophysics Data System (ADS)

    James, M. R.; Robson, S.

    2012-12-01

    Data for detailed digital elevation models (DEMs) are usually collected by expensive laser-based techniques, or by photogrammetric methods that require expertise and specialist software. However, recent advances in computer vision research now permit 3D models to be automatically derived from unordered collections of photographs, and offer the potential for significantly cheaper and quicker DEM production. Here, we review the advantages and limitations of this approach and, using imagery of the summit craters of Piton de la Fournaise, compare the precisions obtained with those from formal close range photogrammetry. The surface reconstruction process is based on a combination of structure-from-motion and multi-view stereo algorithms (SfM-MVS). Using multiple photographs of a scene taken from different positions with a consumer-grade camera, dense point clouds (millions of points) can be derived. Processing is carried out by automated 'reconstruction pipeline' software downloadable from the internet. Unlike traditional photogrammetric approaches, the initial reconstruction process does not require the identification of any control points or initial camera calibration and is carried out with little or no operator intervention. However, such reconstructions are initially un-scaled and un-oriented so additional software has been developed to permit georeferencing. Although this step requires the presence of some control points or features within the scene, it does not have the relatively strict image acquisition and control requirements of traditional photogrammetry. For accuracy, and to allow error analysis, georeferencing observations are made within the image set, rather than requiring feature matching within the point cloud. Application of SfM-MVS is demonstrated using images taken from a microlight aircraft over the summit of Piton de la Fournaise volcano (courtesy of B. van Wyk de Vries). 133 images, collected with a Canon EOS D60 and 20 mm fixed focus lens, were

  14. High-resolution digital elevation models from single-pass TanDEM-X interferometry over mountainous regions: A case study of Inylchek Glacier, Central Asia

    NASA Astrophysics Data System (ADS)

    Neelmeijer, Julia; Motagh, Mahdi; Bookhagen, Bodo

    2017-08-01

    This study demonstrates the potential of using single-pass TanDEM-X (TDX) radar imagery to analyse inter- and intra-annual glacier changes in mountainous terrain. Based on SAR images acquired in February 2012, March 2013 and November 2013 over the Inylchek Glacier, Kyrgyzstan, we discuss in detail the processing steps required to generate three reliable digital elevation models (DEMs) with a spatial resolution of 10 m that can be used for glacial mass balance studies. We describe the interferometric processing steps and the influence of a priori elevation information that is required to model long-wavelength topographic effects. We also focus on DEM alignment to allow optimal DEM comparisons and on the effects of radar signal penetration on ice and snow surface elevations. We finally compare glacier elevation changes between the three TDX DEMs and the C-band shuttle radar topography mission (SRTM) DEM from February 2000. We introduce a new approach for glacier elevation change calculations that depends on the elevation and slope of the terrain. We highlight the superior quality of the TDX DEMs compared to the SRTM DEM, describe remaining DEM uncertainties and discuss the limitations that arise due to the side-looking nature of the radar sensor.

  15. The neurosciences research program at MIT and the beginning of the modern field of neuroscience.

    PubMed

    Adelman, George

    2010-01-15

    The interdisciplinary field, "neuroscience," began at MIT in 1962 with the founding of the Neurosciences Research Program (NRP) by Francis O. Schmitt and a group of US and international scientists - physical, biological, medical, and behavioral - interested in understanding the brain basis of behavior and mind. They organized and held specialist meetings of basic topics in neuroscience, and the journal and book publications over the next 20 years, based on these meetings, helped establish the new field.

  16. The MIT Laser-Driven Target of Nuclear Polarized Hydrogen Gas

    NASA Astrophysics Data System (ADS)

    Clasie, B.; Crawford, C.; Dutta, D.; Gao, H.; Seely, J.; Xu, W.

    2007-04-01

    The laser-driven target at the Massachusetts Institute of Technology (MIT) produced nuclear polarized hydrogen gas in a configuration similar to that used in scattering experiments. The best result achieved was 50.5% polarization with 58.2% degree of dissociation of the sample beam exiting the storage cell at a hydrogen flow rate of 1.1 × 1018 atoms/s.

  17. The MIT high resolution X-ray spectroscopy instruments on AXAF

    NASA Technical Reports Server (NTRS)

    Canizares, C. R.; Dewey, D.; Galton, E. B.; Markert, T. H.; Smith, Henry I.; Schattenburg, M. L.; Woodgate, B. E.; Jordan, S.

    1992-01-01

    The general design and performance characteristics of MIT's two dispersive spectrometers, the Bragg Crystal Spectrometer (BCS) and the High Energy Transmission Grating Spectrometer (HETG), now being developed for the Advanced X-ray Astrophysics Facility (AXAF), are described. Particular attention is given to the development of the critical technologies incorporated into these instruments, including BCS diffractors, imaging gas flow proportional counters, and grating elements for the HETG. The principal stages and the current status of the developments are reviewed.

  18. MultiScheme: A Parallel Processing System Based on MIT (Massachusetts Institute of Technology) Scheme.

    DTIC Science & Technology

    1987-09-01

    Proc. Sixth National Conference on Artificial Intelliegence , 1987. .5W %" p 4’: ¢f ,p£ .𔃼 5-. ..,.; .- k.. . -,. ,....... .-. .. . . )-i181 30...1111lihe giiahag colletctedl. Thec task is a Way I, ()-clIllt tv i r asulils IS the core of inuch work ill artificial lintelligenice. E a vit I-s mit vet...Inst. of Technology, Artificial Intelligence Laboratory, December 1977. ,[10] John Batal, Edmund Goodhue, Chris Hanson, Howie Shrobe, Richard M . Stalman

  19. Teleoperation experiments with a Utah/MIT hand and a VPL DataGlove

    NASA Technical Reports Server (NTRS)

    Clark, D.; Demmel, J.; Hong, J.; Lafferriere, Gerardo; Salkind, L.; Tan, X.

    1989-01-01

    A teleoperation system capable of controlling a Utah/MIT Dextrous Hand using a VPL DataGlove as a master is presented. Additionally the system is capable of running the dextrous hand in robotic (autonomous) mode as new programs are developed. The software and hardware architecture used is presented and the experiments performed are described. The communication and calibration issues involved are analyzed and applications to the analysis and development of automated dextrous manipulations are investigated.

  20. Edelgase als Tracer für Wechselwirkungen von Krusten- und Mantelfluiden mit diamantführenden Gesteinen des östlichen Baltischen Schildes

    NASA Astrophysics Data System (ADS)

    Wiersberg, Thomas

    2001-11-01

    in Folge von U- und Th-Zerfallsprozessen. Wie unterschiedliche thermische Entgasungsmuster für 40Ar und 36Ar zeigen, ist 36Ar in Fluideinschlüssen konzentriert. Das 40Ar/36Ar-Isotopenverhältnis der Fluideinschlüsse von Lamproiten aus Kostamuksha ist antikorreliert mit der durch thermische Extraktion bestimmten Gesamtmenge an 36Ar. Argon aus Fluideinschlüssen setzt sich daher aus zwei Komponenten zusammen: Einer Komponente mit atmosphärischer Argon-Isotopenzusammensetzung und einer krustalen Komponente mit einem Isotopenverhältnis 40Ar/36Ar > 6000. Diffusion von radiogenem 40Ar aus der Kristallmatrix in die Fluideinschlüsse spielt keine wesentliche Rolle. Kimberlite aus Poria Guba und Kandalaksha zeigen anhand der Helium- und z. T. auch der Neon-Isotopenzusammensetzung eine Mantelkomponente in den Fluideinschlüssen an. Bei einem angenommenen 20Ne/22Ne-Isotopenverhältnis von 12,5 in der Mantelquelle ergibt sich ein 21Ne/22Ne-Isotopenverhältnis von 0,073 ± 0,011 sowie ein 3He/4He-Isotopenverhältnis, welches im Vergleich zum subkontinentalem Mantel (Dunai und Baur, 1995) stärker radiogen geprägt ist. Solche Isotopensignaturen sind mit höheren Konzentrationen an Uran und Thorium in der Mantelquelle der Kimberlite zu erklären. Rb-Sr- und Sm-Nd-Altersbestimmungen erfolgten von russischer Seite (Belyatskii et al., 1997; Nikitina et al., 1999) und ergeben ein Alter von 1,23 Ga für den Lamproitvulkanismus in Kostamuksha. Eigene K-Ar-Datierungen an Phlogopiten und Kalifeldspäten stimmen mit einem Alter von 1193 ± 20 Ma fast mit den Rb-Sr- und Sm-Nd-Altern überein. Die K-Ar-Datierung an einem Phlogopit aus Poria Guba, separiert aus dem Kimberlit PGK 12a, ergibt ein Alter von 396 Ma, ebenfalls in guter Übereinstimmung mit Rb-Sr-und Sm-Nd-Altern (ca. 400 Ma, Lokhov, pers. Mitteilung). K-Ar-Altersbestimmungen an Gesamtgestein aus Poria Guba erbrachten kein schlüssiges Alter. Die Rb-Sr- und Sm-Nd-Alter des Lamproitmagmatismus in Poria Guba betragen 1,72 Ga

  1. Fußball mit Wissenschaftlichem Maß: Bananenflanken, Flatterbälle, Kopfballkämpfe

    NASA Astrophysics Data System (ADS)

    Mathelitsch, Leopold; Thaller, Sigrid

    2006-05-01

    Die physikalische Betrachtung des Fußballs liefert spannende Resultate. Wegen der geringen Torzahl spielt der Zufall bei Sieg oder Niederlage stärker mit als in anderen Sportarten. Fußball ist daher mit gewissen statistischen Eigenschaften radioaktiver Quellen vergleichbar. Gleich mehrere physikalische Effekte beeinflussen die Flugbahn des Balls. Der Magnus-Effekt zum Beispiel ermöglicht erst Bananenflanken. Pfeift ein Schiedsrichter falsch, dann wird er nicht selten von seiner Sehperspektive getäuscht.

  2. Acceptance and Operational Test Report for Neutron and Gamma Probe Application to Tank 241-SY-101 MITs

    SciTech Connect

    CANNON, N.S.

    1999-08-12

    This Operational Test Report (OTR) presents the results of the ATP/OTP testing performed to verify that newly procured neutron and gamma probes (reduced diameter design modifications) for operation in the Tank 241-SY-101 MITs are compatible with existing LOW van instrumentation and hardware. This verification was accomplished and a set of moisture data versus elevation were obtained from the Tank 241-SY-101 MITs as part of this testing program.

  3. Gaussian frequency blending algorithm with matrix inversion tomosynthesis (MITS) and filtered back projection (FBP) for better digital breast tomosynthesis reconstruction

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Lo, Joseph Y.; Baker, Jay A.; Dobbins, James T., III

    2006-03-01

    Breast cancer is a major problem and the most common cancer among women. The nature of conventional mammpgraphy makes it very difficult to distinguish a cancer from overlying breast tissues. Digital Tomosynthesis refers to a three-dimensional imaging technique that allows reconstruction of an arbitrary set of planes in the breast from limited-angle series of projection images as the x-ray source moves. Several tomosynthesis algorithms have been proposed, including Matrix Inversion Tomosynthesis (MITS) and Filtered Back Projection (FBP) that have been investigated in our lab. MITS shows better high frequency response in removing out-of-plane blur, while FBP shows better low frequency noise propertities. This paper presents an effort to combine MITS and FBP for better breast tomosynthesis reconstruction. A high-pass Gaussian filter was designed and applied to three-slice "slabbing" MITS reconstructions. A low-pass Gaussian filter was designed and applied to the FBP reconstructions. A frequency weighting parameter was studied to blend the high-passed MITS with low-passed FBP frequency components. Four different reconstruction methods were investigated and compared with human subject images: 1) MITS blended with Shift-And-Add (SAA), 2) FBP alone, 3) FBP with applied Hamming and Gaussian Filters, and 4) Gaussian Frequency Blending (GFB) of MITS and FBP. Results showed that, compared with FBP, Gaussian Frequency Blending (GFB) has better performance for high frequency content such as better reconstruction of micro-calcifications and removal of high frequency noise. Compared with MITS, GFB showed more low frequency breast tissue content.

  4. A metabolic signature for long life in the Caenorhabditis elegans Mit mutants.

    PubMed

    Butler, Jeffrey A; Mishur, Robert J; Bhaskaran, Shylesh; Rea, Shane L

    2013-02-01

    Mit mutations that disrupt function of the mitochondrial electron transport chain can, inexplicably, prolong Caenorhabditis elegans lifespan. In this study we use a metabolomics approach to identify an ensemble of mitochondrial-derived α-ketoacids and α-hydroxyacids that are produced by long-lived Mit mutants but not by other long-lived mutants or by short-lived mitochondrial mutants. We show that accumulation of these compounds is dependent on concerted inhibition of three α-ketoacid dehydrogenases that share dihydrolipoamide dehydrogenase (DLD) as a common subunit, a protein previously linked in humans with increased risk of Alzheimer's disease. When the expression of DLD in wild-type animals was reduced using RNA interference we observed an unprecedented effect on lifespan - as RNAi dosage was increased lifespan was significantly shortened, but, at higher doses, it was significantly lengthened, suggesting that DLD plays a unique role in modulating length of life. Our findings provide novel insight into the origin of the Mit phenotype. © 2012 The Authors Aging Cell © 2012 Blackwell Publishing Ltd/Anatomical Society of Great Britain and Ireland.

  5. Clinical accuracy of inflationary oscillometry in pregnancy and pre-eclampsia: Omron-MIT Elite.

    PubMed

    Chung, Y; Brochut, M C; de Greeff, A; Shennan, A H

    2012-10-01

    To evaluate the accuracy of the Omron MIT Elite in pregnancy and pre-eclampsia according to the British Hypertension Society protocol (BHS). Prospective observational study. Antenatal clinics and wards at St. Thomas' Hospital (London, UK). Forty-five pregnant women including 15 with pre-eclampsia. Nine sequential same arm blood pressure (BP) measurements were taken from each woman by trained observers, alternating between mercury sphygmomanometry and the test device. Grading criteria of the BHS protocol (A/B grade=pass; C/D=fail). The Omron MIT Elite achieved a grade A/A in both pregnancy and pre-eclampsia. The mean difference (SD) between the mercury standard and the device in pregnancy was -1.1 (5.2)mmHg and 1.5 (4.8)mmHg for systolic and diastolic BP respectively compared to 0.2 (5.3)mmHg and 2.2 (5.5)mmHg in pre-eclampsia. The Omron MIT Elite can be recommended for use in pregnancy and pre-eclampsia according to the BHS protocol. To date, this is the most accurate automated BP device validated in pre-eclampsia. Copyright © 2012. Published by Elsevier B.V.

  6. Embryonic expression of zebrafish MiT family genes tfe3b, tfeb, and tfec.

    PubMed

    Lister, James A; Lane, Brandon M; Nguyen, Anhthu; Lunney, Katherine

    2011-11-01

    The MiT family comprises four genes in mammals: Mitf, Tfe3, Tfeb, and Tfec, which encode transcription factors of the basic-helix-loop-helix/leucine zipper class. Mitf is well-known for its essential role in the development of melanocytes, however the functions of the other members of this family, and of interactions between them, are less well understood. We have now characterized the complete set of MiT genes from zebrafish, which totals six instead of four. The zebrafish genome contain two mitf (mitfa and mitfb), two tfe3 (tfe3a and tfe3b), and single tfeb and tfec genes; this distribution is shared with other teleosts. We present here the sequence and embryonic expression patterns for the zebrafish tfe3b, tfeb, and tfec genes, and identify a new isoform of tfe3a. These findings will assist in elucidating the roles of the MiT gene family over the course of vertebrate evolution. Copyright © 2011 Wiley-Liss, Inc.

  7. A METABOLIC SIGNATURE FOR LONG-LIFE IN THE C. ELEGANS MIT MUTANTS

    PubMed Central

    Butler, Jeffrey A.; Mishur, Robert J.; Bhaskaran, Shylesh; Rea, Shane L.

    2012-01-01

    SUMMARY Mit mutations that disrupt function of the mitochondrial electron transport chain can, inexplicably, prolong Caenorhabditis elegans lifespan. In this study we use a metabolomics approach to identify an ensemble of mitochondrial-derived α-ketoacids and α-hydroxyacids that are produced by long-lived Mit mutants but not by other long-lived mutants or by short-lived mitochondrial mutants. We show that accumulation of these compounds is dependent upon concerted inhibition of three α-ketoacid dehydrogenases that share dihydrolipoamide dehydrogenase (DLD) as a common subunit, a protein previously linked in humans with increased risk of Alzheimer’s disease. When the expression of DLD in wild type animals was reduced using RNA interference we observed an unprecedented effect on lifespan - as RNAi dosage was increased lifespan was significantly shortened but, at higher doses, it was significantly lengthened, suggesting DLD plays a unique role in modulating length of life. Our findings provide novel insight into the origin of the Mit phenotype. PMID:23173729

  8. [COPD und Klangtherapie: Pilotstudie zur Wirksamkeit einer Behandlung mit Körpertambura bei COPD-Patienten].

    PubMed

    Hartwig, Bernhard; Schmidt, Stefan; Hartwig, Isabella

    2016-01-01

    Hintergrund: Erkrankungen der Atemorgane treten mit steigendem Alter öfter auf, nehmen weltweit zu und sind häufige Ursachen für Morbidität und Mortalität. In dieser Pilotstudie wurde der Frage nachgegangen, ob eine einmalige 10-minütige Behandlung mit einer Körpertambura eine signifikante und effektive Verbesserung der Lungenfunktion von Patienten mit chronisch-obstruktiver Lungenerkrankung (COPD; GOLD-Stadium A oder B) erbringen kann. Patienten und Methoden: 54 Probanden konnten je zur Hälfte in eine Behandlungsgruppe (Körpertambura) und eine aktive Kontrollgruppe (Atemtherapie) randomisiert werden. Eine Bestimmung der Lungenfunktionsmessparameter «Einsekundenkapazität» (FEV1) und «inspiratorische Vitalkapazität» (IVC) zu den Zeitpunkten T1 (Baseline), T2 (direkt nach Behandlung) und als Follow-up etwa 3 Wochen nach T1 (T3). Ergebnisse: Die Behandlungsgruppe zeigte sich der Kontrollgruppe in beiden Werten signifikant überlegen. Die Zeit-×-Gruppe-Interaktion (Varianzanalyse) ergab p = 0,001 (FEV1) bzw. p = 0,04 (IVC). Die Behandlungsgruppe zeigte bei beiden Werten eine Verbesserung von klinischer Relevanz. Schlussfolgerung: Diese Ergebnisse zeigen, dass die Klangbehandlung mittels einer Körpertambura - neben den schulmedizinischen, leitliniengerechten Therapien - eine zusätzliche, nebenwirkungsarme, aber durchaus klinisch wirksame Option für die Behandlung von COPD-Patienten darstellen kann, um deren Lebensqualität zu stabilisieren und zu verbessern. © 2016 S. Karger GmbH, Freiburg.

  9. Embryonic expression of zebrafish MiT family genes tfe3b, tfeb, and tfec

    PubMed Central

    Lister, James A.; Lane, Brandon M.; Nguyen, AnhThu; Lunney, Katherine

    2011-01-01

    The MiT family comprises four genes in mammals: Mitf, Tfe3, Tfeb, and Tfec, which encode transcription factors of the basic-helix-loop-helix/leucine zipper class. Mitf is well-known for its essential role in the development of melanocytes, however the functions of the other members of this family, and of interactions between them, are less well understood. We have now characterized the complete set of MiT genes from zebrafish, which totals six instead of four. The zebrafish genome contain two mitf (mitfa and mitfb), two tfe3 (tfe3a and tfe3b), and single tfeb and tfec genes; this distribution is shared with other teleosts. We present here the sequence and embryonic expression patterns for the zebrafish tfe3b, tfeb and tfec genes, and identify a new isoform of tfe3a. These findings will assist in elucidating the roles of the MiT gene family over the course of vertebrate evolution. PMID:21932325

  10. BOREAS HYD-8 DEM Data Over the NSA-MSA and SSA-MSA in the UTM Projection

    NASA Technical Reports Server (NTRS)

    Wang, Xue-Wen; Hall, Forrest G. (Editor); Knapp, David E. (Editor); Band, L. E.; Smith, David E. (Technical Monitor)

    2000-01-01

    The BOREAS HYD-8 team focused on describing the scaling behavior of water and carbon flux processes at local and regional scales. These DEMs were produced from digitized contours at a cell resolution of 100 meters. Vector contours of the area were used as input to a software package that interpolates between contours to create a DEM representing the terrain surface. The vector contours had a contour interval of 25 feet. The data cover the BOREAS MSAs of the SSA and NSA and are given in a UTM map projection. Most of the elevation data from which the DEM was produced were collected in the 1970s or 1980s. The data are stored in binary, image format files. The data files are available on a CD-ROM (see document number 20010000884) or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  11. Delta-K Wideband SAR Interferometry for DEM Generation and Persistent Scatterers Using TeraSAR-X

    NASA Astrophysics Data System (ADS)

    Brcic, Ramon; Eineder, Michael; Bamler, Richard; Steinbrecher, Ulrich; Schulze, Daniel; Metzig, Robert; Papathanassiou, Konstantinos; Nagler, Thomas; Mueller, Florian; Suess, Martin

    2010-03-01

    Wideband SAR systems such as TerraSAR-X allow estimation of the absolute interferometric phase without resorting to error prone phase unwrapping. This is achieved through the delta-k technique that exploits frequency diversity within the range bandwidth to simulate a SAR system with a much longer carrier wavelength. This benefits all interferometric applications including DEM generation and land surface motion determination. Here we present the results of an ESA study (21318/07/NL/HE) into using delta-k absolute phase estimation for DEM generation and PSI (Persistent Scatterer Interferometry). Using TerraSAR- X data, examples from a delta-k DEM generation system are shown which avoid the errors induced by conventional phase unwrapping. For PSI, the possibilities of absolute phase estimation for a single PS are explored in theory and examples where wideband estimation is compared to conventional PSI processing for a stack of acquisitions over Paris.

  12. Multi-Temporal Investigation of Greenland Ice Sheet Snow Facies Using TanDEM-X Mission Data

    NASA Astrophysics Data System (ADS)

    Rizzoli, Paola; Martone, Michele; Brautigam, Benjamin; Rott, Helmut; Moreira, Alberto

    2016-08-01

    This paper presents the first results of the developed approach for classifying Greenland ice sheet snow facies, based on the use of interferometric TanDEM-X SAR data. Large-scale mosaics of radar backscatter and volume decorrelation, derived from the interferometric coherence, are used as input data set for applying a classification algorithm based on the c-means fuzzy clustering. The unique data set provided by TanDEM-X is particularly suitable for this analysis due to the single-pass bistatic acquisition mode which does not suffer from temporal decorrelation. The obtained results have been verified with external snow melt data. Moreover, independent multi-temporal TanDEM-X backscatter data and interferometric time series have been analyzed as well.

  13. Ökophysik: Plaudereien über das Leben auf dem Land, im Wasser und in der Luft

    NASA Astrophysics Data System (ADS)

    Nachtigall, W.

    Prof. em. Dr. rer. nat. Werner Nachtigall, geb. 1934, war als Zoophysiologe und Biophysiker Leiter des Zoologischen Instituts der Universität des Saarlandes in Saarbrücken. In Forschung und Ausbildung hat er sich insbesondere mit Aspekten der Technischen Biologie und Bionik befasst und mit seinen Forschergruppen viele Basisdaten insbesondere zur Ökologie, Physiologie und Physik des Fliegens und Schwimmens aber auch zur Stabilität beispielsweise der Gräser erarbeitet. Lebewesen überraschen immer wieder durch ihre "Biodiversität", ihre hochspezifischen Ausgestaltungen und Anpassungen.

  14. Forward Tracking with the silicon vertex detector at the CDF experiment in RUN II. Spurrekonstruktion in Vorwärtsrichtung mit dem Silizium-Vertexdetektor des CDF-Experiments in RUN II

    SciTech Connect

    Scheidle, Thorsten

    2007-02-01

    The Standard Model of particle physics describes the fundamental particles of matter and their interactions. In order to test the Standard Model, determine free parameters and search for new particles beyond the Standard Model, large accelerator complexes produce particle collisions which are recorded by large detectors. Until the start of the Large Hadron Collider at CERN, the Tevatron accelerator at Fermilab provides particle collisions with the highest center-of-mass energy of √s = 1.96 TeV. The two multipurpose detector systems CDF and DØ record the collisions. A multipurpose detector system is built of several specialized sub-detectors to measure different particle properties. A particle which passes the detector deposits energy by interacting with the detector material. A silicon strip detector and a wire drift chamber detect charged particles close to the collision point. The energy loss in these systems is relatively small, instead many different small energy depositions are produced by one passing particle. These so-called hits can be combined to a track, indicating the path of the particle. A homogeneous magnetic field surrounding the tracking system forces a charged particle to a helix path which allows a momentum measurement by measuring the curvature. The reconstruction of particle tracks is a non-trivial task. First all position measurements belonging to a particle along a hypothetical helix have to be found and then all position information has to be combined to a reconstructed track and its parameters. I focused my work on the track reconstruction in the silicon detector which provides a good position resolution of the measurements.

  15. May 1, 1989- A Critical Turning Point in the Cold Fusion Saga: APS, MIT and the Real Story

    NASA Astrophysics Data System (ADS)

    Mallove, Sc. D.; Eugene, F.; Chubb, Talbot

    2001-04-01

    As Chief Science Writer at the MIT News Office from 1987 through 1991, and as an engineer (MIT, S.B. 1969, S.M. 1970) familiar with heat measurements and the various other experiment claims, I was in a position to ascertain the true facts surrounding: the media and Press Conference events at MIT before and after May 1, 1989; the ill-fated calorimetric experiment performed by the MIT Plasma Fusion Center; and the MIT Administration's so-called investigation of this experiment. This activity led to wide-spread disparagement of the Fleischmann-Pons claims. A reconstruction of these events will be outlined, together with original supporting evidence that confirm that the "standard story" of how cold fusion was "debunked" at the May 1, 1989 APS meeting in Baltimore is not only wrong, but catastrophically so(Eugene Mallove, Fire from Ice: Searching for the Truth Behind the Cold Fusion Furor. (John Wiley & Sons, 1991))^,(Infinite Energy Magazine, Issue #24, March/April 1999, 10th Anniversary of Cold Fusion issue. (Includes time-lines and 55-page "MIT Special Report") ).

  16. The EVE plus RHESSI DEM for Solar Flares, and Implications for Residual Non-Thermal X-Ray Emission

    NASA Astrophysics Data System (ADS)

    McTiernan, James; Caspi, Amir; Warren, Harry

    2016-05-01

    Solar flare spectra are typically dominated by thermal emission in the soft X-ray energy range. The low energy extent of non-thermal emission can only be loosely quantified using currently available X-ray data. To address this issue, we combine observations from the EUV Variability Experiment (EVE) on-board the Solar Dynamics Observatory (SDO) with X-ray data from the Reuven Ramaty High Energy Spectroscopic Imager (RHESSI) to calculate the Differential Emission Measure (DEM) for solar flares. This improvement over the isothermal approximation helps to resolve the ambiguity in the range where the thermal and non-thermal components may have similar photon fluxes. This "crossover" range can extend up to 30 keV.Previous work (Caspi et.al. 2014ApJ...788L..31C) concentrated on obtaining DEM models that fit both instruments' observations well. For this current project we are interested in breaks and cutoffs in the "residual" non-thermal spectrum; i.e., the RHESSI spectrum that is left over after the DEM has accounted for the bulk of the soft X-ray emission. As in our earlier work, thermal emission is modeled using a DEM that is parametrized as multiple gaussians in temperature. Non-thermal emission is modeled as a photon spectrum obtained using a thin-target emission model ('thin2' from the SolarSoft Xray IDL package). Spectra for both instruments are fit simultaneously in a self-consistent manner.For this study, we have examined the DEM and non-thermal resuidual emission for a sample of relatively large (GOES M class and above) solar flares observed from 2011 to 2014. The results for the DEM and non-thermal parameters found using the combined EVE-RHESSI data are compared with those found using only RHESSI data.

  17. Comparing ArcticDEM against LiDAR in Alaska: Tests of uncertainty in elevation and hydrologic delineation

    NASA Astrophysics Data System (ADS)

    Crosby, B. T.

    2016-12-01

    The ArcticDEM, created by the Polar Geospatial Center using stereo, high-resolution satellite imagery, promises to transform our capacity to execute geospatial analyses in northern latitudes. The two meter ArcticDEM replaces the 60 meter posting USGS NED, offering a 30x increase in resolution that enables change detection and quantification of cold region morphometry not possible before. ArcticDEM elevations are constrained by an Arctic-wide ground control dataset but the product has not yet been compared against continuous raster elevation data. In order to provide a raster-based uncertainty analysis that considers offsets in both the vertical and horizontal dimensions, we compare ArcticDEM against two different one meter resolution LiDAR products. These products, created by the State of Alaska for evaluation of roadway and utility corridors span gradients in relief, geomorphic process and climate. Small but systematic biases exist for higher relief topography that may be related to the broad range of oblique views present in a single swath of satellite data. Though ArcticDEM provides a sea change in our ability to resolve arctic landforms, it is unclear whether the product can effectively delineate channel form. Stereo imagery only enables the creation of a digital surface model (DSM) that include the forms of trees and shrubs. These vegetation elements, the presence/absence of ice at the time of image acquisition and other factors complicate the efficacy of flow routing models and our ability to extract channel characteristics from elevation datasets. This presentation articulates the opportunities and limitations presented by the ArcitcDEM product and others like Structure from Motion that rely on imagery for the generation of high resolution topography.

  18. Automatic Delineation of Sea-Cliff Limits Using Lidar-Derived High-Resolution DEMs in Southern California

    NASA Astrophysics Data System (ADS)

    Palaseanu, M.; Danielson, J.; Foxgrover, A. C.; Barnard, P.; Thatcher, C.; Brock, J. C.

    2014-12-01

    Seacliff erosion is a serious hazard with implications for coastal management, and is often estimated using successive hand digitized cliff tops or bases (toe) to assess cliff retreat. Traditionally the recession of the cliff top or cliff base is obtained from aerial photographs, topographic maps, or in situ surveys. Irrespective of how or what is measured to categorize cliff erosion, the position of the cliff top and cliff base is important. Habitually, the cliff top and base are hand digitized even when using high resolution lidar derived DEMs. Even if efforts were made to standardize and eliminate as much as possible any digitizing subjectivity, the delineation of cliffs is time consuming, and depends on the analyst's interpretation. We propose an automatic procedure to delineate the cliff top and base from high resolution bare-earth DEMs. The method is based on bare-earth high-resolution DEMs, generalized coastal shorelines and approximate measurements of distance between the shoreline and the cliff top. The method generates orthogonal transects and profiles with a minimum spacing equal to the DEM resolution and extracts for each profile xyz coordinates for cliff's top and toe, as well as second major positive and negative inflections (second top and toe) along the profile. The difference between the automated and digitized top and toe, respectively, is smaller than the DEM error margin for over 82% of the top points and 86% of the toe points along a stretch of coast in Del Mar, CA. The larger errors were due either to the failure to remove all vegetation from the bare-earth DEM or errors of interpretation during hand digitizing. The automatic method was further applied between Point Conception and Los Angeles Harbor, CA. This automatic method is repeatable, takes advantage of the bare-earth high-resolution, and is more efficient.

  19. Insight into the adsorption profiles of the Saprolegnia monoica chitin synthase MIT domain on POPA and POPC membranes by molecular dynamics simulation studies.

    PubMed

    Kuang, Guanglin; Liang, Lijun; Brown, Christian; Wang, Qi; Bulone, Vincent; Tu, Yaoquan

    2016-02-21

    The critical role of chitin synthases in oomycete hyphal tip growth has been established. A microtubule interacting and trafficking (MIT) domain was discovered in the chitin synthases of the oomycete model organism, Saprolegnia monoica. MIT domains have been identified in diverse proteins and may play a role in intracellular trafficking. The structure of the Saprolegnia monoica chitin synthase 1 (SmChs1) MIT domain has been recently determined by our group. However, although our in vitro assay identified increased strength in interactions between the MIT domain and phosphatidic acid (PA) relative to other phospholipids including phosphatidylcholine (PC), the mechanism used by the MIT domain remains unknown. In this work, the adsorption behavior of the SmChs1 MIT domain on POPA and POPC membranes was systematically investigated by molecular dynamics simulations. Our results indicate that the MIT domain can adsorb onto the tested membranes in varying orientations. Interestingly, due to the specific interactions between MIT residues and lipid molecules, the binding affinity to the POPA membrane is much higher than that to the POPC membrane. A binding hotspot, which is critical for the adsorption of the MIT domain onto the POPA membrane, was also identified. The lower binding affinity to the POPC membrane can be attributed to the self-saturated membrane surface, which is unfavorable for hydrogen-bond and electrostatic interactions. The present study provides insight into the adsorption profile of SmChs1 and additionally has the potential to improve our understanding of other proteins containing MIT domains.

  20. Deletion of PdMit1, a homolog of yeast Csg1, affects growth and Ca(2+) sensitivity of the fungus Penicillium digitatum, but does not alter virulence.

    PubMed

    Zhu, Congyi; Wang, Weili; Wang, Mingshuang; Ruan, Ruoxin; Sun, Xuepeng; He, Meixian; Mao, Cungui; Li, Hongye

    2015-04-01

    GDP-mannose:inositol-phosphorylceramide (MIPC) and its derivatives are important for Ca(2+) sensitization of Saccharomyces cerevisiae and for the virulence of Candida albicans, but its role in the virulence of plant fungal pathogens remains unclear. In this study, we report the identification and functional characterization of PdMit1, the gene encoding MIPC synthase in Penicillium digitatum, one of the most important pathogens of postharvest citrus fruits. To understand the function of PdMit1, a PdMit1 deletion mutant was generated. Compared to its wild-type control, the PdMit1 deletion mutant exhibited slow radial growth, decreased conidia production and delayed conidial germination, suggesting that PdMit1 is important for the growth of mycelium, sporulation and conidial germination. The PdMit1 deletion mutant also showed hypersensitivity to Ca(2+). Treatment with 250 mmol/l Ca(2+) induced vacuole fusion in the wild-type strain, but not in the PdMit1 deletion mutant. Treatment with 250mmol/lCaCl2 upregulated three Ca(2+)-ATPase genes in the wild-type strain, and this was significantly inhibited in the PdMit1 deletion mutant. These results suggest that PdMit1 may have a role in regulating vacuole fusion and expression of Ca(2+)-ATPase genes by controlling biosynthesis of MIPC, and thereby imparts P. digitatum Ca(2+) tolerance. However, we found that PdMit1 is dispensable for virulence of P. digitatum.

  1. The Use of DEM to Capture the Dynamics of the Flow of Solid Pellets in a Single Screw Extruder

    NASA Astrophysics Data System (ADS)

    Hong, He; Covas, J. A.; Gaspar-Cunha, A.

    2007-05-01

    Despite of the numerical developments on the numerical modeling of polymer plasticating single screw extrusion, the initial stages of solids conveying are still treated unsatisfactorily, a simple plug flow condition being assumed. It is well known that this produces poor predictions of relevant process parameters, e.g., output. This work reports on attempt to model the process using the Discrete Element Method (DEM) with the aim of unveiling the dynamics of the process. Using DEM each pellet is taken as a separate unit, thus predictions of flow patterns, velocity fields and degree of filling are possible. We present the algorithm and a few preliminary results.

  2. Elevation-Based Sea-Level Rise Vulnerability Assessment of Mindanao, Philippines: are Freely-Available 30-M Dems Good Enough?

    NASA Astrophysics Data System (ADS)

    Santillan, J. R.; Makinano-Santillan, M.

    2017-09-01

    We assessed the vertical accuracies and uncertainties of three freely-available global DEMs as inputs to elevation-based sea-level rise vulnerability assessment of Mindanao, Philippines - an area where above average SLR of 14.7 mm/year was recently found. These DEMs are the Shuttle Radar Topography Mission (SRTM) DEM, ASTER Global DEM (GDEM Version 2), and ALOS World 3D-30 (AW3D30). Using 2,076 ground control points, we computed each DEM's vertical accuracies and uncertainties, and from these we determined the smallest increment of sea-level rise (SLRImin) that should be considered when using the DEMs for SLR impact assessment, as well as the Minimum Planning Timeline (TLmin) for an elevation-based SLR assessment. Results of vertical accuracy assessment revealed Root Mean Square Errors of 9.80 m for ASTER GDEM V2, 5.16 m for SRTM DEM, and 4.32 m for AW3D30. Vertical uncertainties in terms of the Linear Error at 95 % Confidence (LE95) were found to be as follows: 19.21 m for ASTER GDEM V2, 10.12 m for SRTM DEM, and 8.47 m for AW3D30. From these, we found that ASTER GDEM2 is suitable to model SLR increments of at least 38.41 m and it will take 2,613 years for the cumulative water level increase of 14.7 mm/year to reach the minimum SLR increment afforded by this DEM. For the SRTM DEM, SLRImin and TLmin were computed as 20.24 m and 1,377 years, respectively. For the AW3D30, SLRImin and TLmin were computed as 16.92 m and 1,151 years, respectively. These results suggest that the readily available global DEMs' suitability for mapping coastal inundations due to SLR in our study area is limited by their low vertical accuracies and high uncertainties. All the three DEMs do not have the necessary accuracy and minimum uncertainties that will make them suitable for mapping inundations of Mindanao at smaller increments of SLR (e.g., SLR ≤ 5 m). Hence, users who apply any of these DEMs

  3. Semi-automated extraction of landslides in Taiwan based on SPOT imagery and DEMs

    NASA Astrophysics Data System (ADS)

    Eisank, Clemens; Hölbling, Daniel; Friedl, Barbara; Chen, Yi-Chin; Chang, Kang-Tsung

    2014-05-01

    The vast availability and improved quality of optical satellite data and digital elevation models (DEMs), as well as the need for complete and up-to-date landslide inventories at various spatial scales have fostered the development of semi-automated landslide recognition systems. Among the tested approaches for designing such systems, object-based image analysis (OBIA) stepped out to be a highly promising methodology. OBIA offers a flexible, spatially enabled framework for effective landslide mapping. Most object-based landslide mapping systems, however, have been tailored to specific, mainly small-scale study areas or even to single landslides only. Even though reported mapping accuracies tend to be higher than for pixel-based approaches, accuracy values are still relatively low and depend on the particular study. There is still room to improve the applicability and objectivity of object-based landslide mapping systems. The presented study aims at developing a knowledge-based landslide mapping system implemented in an OBIA environment, i.e. Trimble eCognition. In comparison to previous knowledge-based approaches, the classification of segmentation-derived multi-scale image objects relies on digital landslide signatures. These signatures hold the common operational knowledge on digital landslide mapping, as reported by 25 Taiwanese landslide experts during personal semi-structured interviews. Specifically, the signatures include information on commonly used data layers, spectral and spatial features, and feature thresholds. The signatures guide the selection and implementation of mapping rules that were finally encoded in Cognition Network Language (CNL). Multi-scale image segmentation is optimized by using the improved Estimation of Scale Parameter (ESP) tool. The approach described above is developed and tested for mapping landslides in a sub-region of the Baichi catchment in Northern Taiwan based on SPOT imagery and a high-resolution DEM. An object

  4. Hydrologically Correct, Global Paleo-Digital Elevation Models (DEMs): a Maastrichtian (Late Cretaceous) Example

    NASA Astrophysics Data System (ADS)

    Markwick, P. J.

    2001-12-01

    The past surface relief of the Earth is an essential boundary condition for computer-based atmosphere and ocean modeling. It also provides the geographic context for understanding surface processes and biotic distributions and interactions. However, with increased model resolution and the addition of vegetation, soil (weathering) and chemical modules, there is now a need for more robust, detailed paleo-topographies and bathymetries that are fully integrated with the processes being modeled, especially the hydrological system (hydrologically correct). Here I present a new GIS-based, hydrologically correct, paleo-DEM for the Maastrichtian (Late Cretaceous). This project was initiated in 1995 while the author was a graduate at the University of Chicago using the plate reconstructions of Rowley (1995, unpublished). The Maastrichtian paleogeography used in this study is one of a series of 27 global maps, representing the Cretaceous and Cenozoic, being compiled simultaneously to ensure continuity between each time interval. Each map is generated at a scale of 1:30 million in ArcView GIS and ArcInfo, using data from the author's own databases of lithologic, tectonic and fossil information, the lithologic databases of the Paleogeographic Atlas Project (The University of Chicago), a survey of published literature, and DSDP / ODP data. Interpretations of elevation are derived following the methods outlined in Ziegler et al (1985), an understanding of the tectonic regime and evolution of each geographic feature, and the age-depth relationship for the ocean. The Maastrichtian has been completed first to provide the boundary conditions for a coupled atmosphere-ocean experiment. The hydrologically correct global DEM was derived using the elevation contours from the paleogeography and the suite of hydrological tools now available in ArcInfo GRID. The DEM has been constrained by defining areas of paleo-internal drainage, paleo-river mouths and known paleo-river courses. When

  5. Sediment micromechanics in sheet flows induced by asymmetric waves: A CFD-DEM study

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Xiao, Heng

    2016-11-01

    Understanding the sediment transport in oscillatory flows is essential to the investigation of the overall sediment budget for coastal regions. This overall budget is crucial for the prediction of the morphological change of the coastline in engineering applications. Since the sediment transport in oscillatory flows is dense particle-laden flow, appropriate modeling the particle interaction is critical. Although traditional two-fluid approaches have been applied to the study of sediment transport in oscillatory flows, the approaches do not capture the interaction of the particles. The study of the motion of individual sediment particles and their micromechanics (e.g., packing and contact force) in oscillatory flows is still lacking. In this work, a parallel CFD-DEM solver SediFoam that can model the inter-particle collision is applied to study the granular micromechanics of sediment particles in oscillatory flows. The results obtained from the CFD-DEM solver are validated by using the experimental data of coarse and medium sands. The comparison with experimental results suggests that the flow velocity, the sediment flux and the net sediment transport rate predicted by SediFoam are satisfactory. Moreover, the micromechanic quantities of the sediment bed are presented in detail, including the Voronoi concentration, the coordination number, and the particle interaction force. It is demonstrated that the variation of these micromechanic quantities at different phases in the oscillatory cycle is significant, which is due to different responses of the sediment bed. To investigate the structural properties of the sediment bed, the correlation of the Voronoi volume fraction and coordination number is compared to the results from the fluidized bed simulations. The consistency in the comparison indicates the structural micromechanics of sediment transport and fluidized bed are similar despite the differences in flow patterns. From the prediction of the CFD-DEM model, we

  6. Holocene palaeoDEMs for lowland coastal and delta plain landscape reconstructions

    NASA Astrophysics Data System (ADS)

    Cohen, Kim M.; Koster, Kay; Pierik, Harm-Jan; Van der Meulen, Bas; Hijma, Marc; Schokker, Jeroen; Stafleu, Jan

    2017-04-01

    Geological mapping of Holocene deposits of coastal plains, such as that of The Netherlands can reach high resolution (dense population, diverse applied usage) and good time control (14C dating, archaeology). The next step is then to create time sliced reconstructions for stages in the Holocene, peeling of the subrecent and exposing past relief situation. This includes winding back the history of sea-level rise and delta progradation etc. etc. So far, this has mainly be done as 2D series of landscape maps, or as sea-level curve age-depth plots. In the last decade, academic and applied projects at Utrecht University, TNO Geological Survey of The Netherlands and Deltares have developed palaeoDEMs for the Dutch low lands, that are a third main way of showing coastal plain evolution. Importantly, we produce two types of palaeoDEMs: (1) geological surface mapping using deposit contacts from borehole descriptions (and scripted 3D processing techniques - e.g. Van der Meulen et al. 2013) and (2) palaeogroundwater surfaces, using sea-level and inland water-level index-points (and 3D kriging interpolations - e.g. Koster et al. 2016). The applications for the combined palaeoDEMs range from relative sea-level rise mapping and assessment of variation in rate of GIA across the coastal plain, to quantification of soft soil deformation, to analysis of pre-embankment extreme flood levels. Koster, K., Stafleu, J., & Cohen, K.M. (2016). Generic 3D interpolation of Holocene base-level rise and provision of accommodation space, developed for the Netherlands coastal plain and infilled palaeovalleys. Basin Research. DOI 10.1111/bre.12202 Van der Meulen, M.J., Doornenbal, J.C., Gunnink, J.L., Stafleu, J., Schokker, J., Vernes, R.W., Van Geer, F.C., Van Gessel, S.F., Van Heteren, S., Van Leeuwen, R.J.W. & Bakker, M.A.J. (2013). 3D geology in a 2D country: perspectives for geological surveying in the Netherlands. Netherlands Journal of Geosciences, 92, 217-241. DOI 10.1017/S0016774600000184

  7. Turbidity Current Transport using DEM and FEM: a Hybrid Lagrangian-Eulerian Approach

    NASA Astrophysics Data System (ADS)

    Alves, J. L.; Guevara, N. O., Jr.; Silva, C. E.; Alves, F. T.; Gazoni, L. C.; Coutinho, A.; Camata, J.; Elias, R. N.; Paraizo, P.

    2013-05-01

    In this work we describe a contribution to the study of turbidity transport in scales smaller than TFM (two-fluid models), The intent of the work, part of a large scale simulation project, is to assess local, small scale parameters and their upscaling. The hybrid model is based on a Lagrangian-Eulerian approach under a class of the so called Unresolved Discrete Particle Method (UDPM). In this approach, a Lagrangian description is used for the particle system employing the Discrete Element Method (DEM) while a fixed Eulerian mesh is used for the fluid phase modeled by finite element method (FEM), Fluid motion is governed by Navier-Stokes equations which are solved by an appropriate FEM implementation. Closure equation are used to compute drag and lift forces over the particles in the DEM framework. Volume averaged momentum sink terms are included in the fluid equations. The resulting coupled DEM-FEM model is integrated in time with a subcycling scheme. The aforementioned scheme was applied in the simulation of a sedimentation basin as depicted in figures 1 and 2 to investigate flow and deposition features of the suspension in a finer scale. For this purpose a submodel of the basin was generated. Mapping variables back and forth the Eulerian (finite element) model and the Lagrangian (discrete element) model were performed during the subcycled integration of the hybrid model. References: [1] Hoomans, B.P.B., Kuipers, J.A.M., Swaaij, van W.P.M," Granular dynamics Simulation of segregation phenomena in bubbling gas-fluidised beds", Powder Technology, V 109, Issues 1-3, 3 April 2000, pp 41-48; [2] Cho, S.H., Choi,H.G, Yoo, J.Y.,"Direct numerical simulation of fluid flow laden with many particles", International Journal of Multiphase Flow, V 31, Issue 4, April 2005, pp 435-451;; Sedimentation basin: sectioning the turbidity plume in the Eulerian FE model for setting up the discrete particle model. ; Sedimentation Basin: section of the turbidity plume displaying the

  8. Implementation of large-scale landscape evolution modelling to real high-resolution DEM

    NASA Astrophysics Data System (ADS)

    Schroeder, S.; Babeyko, A. Y.

    2012-12-01

    We have developed a surface evolution model to be naturally integrated with 3D thermomechanical codes like SLIM-3D to study coupled tectonic-climate interaction. The resolution of the surface evolution model is independent of that of the underlying continuum box. The surface model follows the concept of the cellular automaton implemented on a regular Eulerian mesh. It incorporates an effective filling algorithm that guarantees flow direction in each cell, D8 search for flow directions, computation of discharges and bedrock incision. Additionally, the model implements hillslope erosion in the form of non-linear, slope-dependent diffusion. The model was designed to be employed not only to synthetic topographies but also to real Digital Elevation Models (DEM). In present work we report our experience with model implication to the 30-meter resolution ASTER GDEM of the Pamir orogen, in particular, to the segment of the Panj river. We start with calibration of the model parameters (fluvial incision and hillslope diffusion coefficients) using direct measurements of Panj incision rates and volumes of suspended sediment transport. Since the incision algorithm is independent on hillslope processes, we first adjust the incision parameters. Power-law exponents of the incision equation were evaluated from the profile curvature of the main Pamir rivers. After that, incision coefficient was adjusted to fit the observed incision rate of 5 mm/y. Once the model results are consistent with the measured data, the calibration of hillslope processes follows. For given critical slope, diffusivity could be fitted to match the observed sediment discharge. Applying of surface evolution model to real DEM reveals specific problems which do not appear when working with synthetic landscapes. One of them is the noise of the satellite-measured topography. In particular, due to the non-vertical observation perspective, satellite may not be able to detect the bottom of the river channel, especially

  9. Structural and Volumetric re-evaluation of the Vaiont landslide using DEM techniques

    NASA Astrophysics Data System (ADS)

    Superchi, Laura; Pedrazzini, Andrea; Floris, Mario; Genevois, Rinaldo; Ghirotti, Monica; Jaboyedoff, Michel

    2010-05-01

    On the 9th October 1963 a catastrophic landslide occurred on the southern slope of the Vaiont dam reservoir. A mass of approximately 270 million m3 collapsed into the reservoir generating a wave which overtopped the dam and hit the town of Longarone and other villages: almost 2000 people lost their lives. The large volume and high velocity of the landslide combined with the great destruction and loss of life that occurred make the Vaiont landslide as a natural laboratory to investigate landslide failure mechanisms and propagation. Geological, structural, geomorphological, hydrogeological and geomechanical elements should be, then, re-analyzed using methods and techniques not available in the '60s. In order to better quantify the volume involved in the movement and to assess the mechanism of the failure, a structural study is a preliminary and necessary step. The structural features have been investigated based on a digital elevation model (DEM) of the pre- and post-landslide topography at a pixel size of 5m and associated software (COLTOP-3D) to create a colored shaded relief map revealing the orientation of morphological features. Besides,the results allowed to identify on both pre- and post-slide surface six main discontinuity sets, some of which influence directly the Vaiont landslide morphology. Recent and old field surveys allowed to validate the COLTOP-3D analysis results. To estimate the location and shape of the sliding surface and to evaluate the volume of the landslide, the SLBL (Sloping Local Base Level) method has been used, a simple and efficient tool that allows a geometric interpretation of the failure surface based on a DEM. The SLBL application required a geological interpretation to define the contours of the landslide and to estimate the possible curvature of the sliding surface, that is defined by interpolating between points considered as limits of the landslide. The SLBL surface of the Vaiont landslide, was obtained from the DEM reconstruction

  10. MARE2DEM: a 2-D inversion code for controlled-source electromagnetic and magnetotelluric data

    NASA Astrophysics Data System (ADS)

    Key, Kerry

    2016-10-01

    This work presents MARE2DEM, a freely available code for 2-D anisotropic inversion of magnetotelluric (MT) data and frequency-domain controlled-source electromagnetic (CSEM) data from onshore and offshore surveys. MARE2DEM parametrizes the inverse model using a grid of arbitrarily shaped polygons, where unstructured triangular or quadrilateral grids are typically used due to their ease of construction. Unstructured grids provide significantly more geometric flexibility and parameter efficiency than the structured rectangular grids commonly used by most other inversion codes. Transmitter and receiver components located on topographic slopes can be tilted parallel to the boundary so that the simulated electromagnetic fields accurately reproduce the real survey geometry. The forward solution is implemented with a goal-oriented adaptive finite-element method that automatically generates and refines unstructured triangular element grids that conform to the inversion parameter grid, ensuring accurate responses as the model conductivity changes. This dual-grid approach is significantly more efficient than the conventional use of a single grid for both the forward and inverse meshes since the more detailed finite-element meshes required for accurate responses do not increase the memory requirements of the inverse problem. Forward solutions are computed in parallel with a highly efficient scaling by partitioning the data into smaller independent modeling tasks consisting of subsets of the input frequencies, transmitters and receivers. Non-linear inversion is carried out with a new Occam inversion approach that requires fewer forward calls. Dense matrix operations are optimized for memory and parallel scalability using the ScaLAPACK parallel library. Free parameters can be bounded using a new non-linear transformation that leaves the transformed parameters nearly the same as the original parameters within the bounds, thereby reducing non-linear smoothing effects. Data

  11. High-resolution Pleiades DEMs and improved mapping methods for the E-Corinth marine terraces

    NASA Astrophysics Data System (ADS)

    de Gelder, Giovanni; Fernández-Blanco, David; Delorme, Arthur; Jara-Muñoz, Julius; Melnick, Daniel; Lacassin, Robin; Armijo, Rolando

    2016-04-01

    The newest generation of satellite imagery provides exciting new possibilities for highly detailed mapping, with ground resolution of sub-metric pixels and absolute accuracy within a few meters. This opens new venues for the analysis of geologic and geomorphic landscape features, especially since photogrammetric methods allow the extraction of detailed topographic information from these satellite images. We used tri-stereo imagery from the Pleiades platform of the CNES in combination with Euclidium software for image orientation, and Micmac software for dense matching, to develop state-of-the-art, 2m-resolution digital elevation models (DEMs) for eight areas in Greece. Here, we present our mapping results for an area in the eastern Gulf of Corinth, which contains one of the most extensive and well-preserved flights of marine terraces world-wide. The spatial extent of the terraces has been determined by an iterative combination of an automated surface classification model for terrain slope and roughness, and qualitative assessment of satellite imagery, DEM hillshade maps, slope maps, as well as detailed topographic analyses of profiles and contours. We determined marine terrace shoreline angles by means of swath profiles that run perpendicularly to the paleo-seacliffs, using the graphical interface TerraceM. Our analysis provided us with a minimum and maximum estimate of the paleoshoreline location on ~750 swath profiles, by using the present-day cliff slope as an approximation for its paleo-cliff counterpart. After correlating the marine terraces laterally we obtained 16 different terrace-levels, recording Quaternary sea-level highstands of both major interglacial and several interstadial periods. Our high-resolution Pleiades-DEMs and improved method for paleoshoreline determination allowed us to produce a marine terrace map of unprecedented detail, containing more terrace sub-levels than hitherto. Our mapping demonstrates that we are no longer limited by the

  12. Revealing topographic lineaments through IHS enhancement of DEM data. [Digital Elevation Model

    NASA Technical Reports Server (NTRS)

    Murdock, Gary

    1990-01-01

    Intensity-hue-saturation (IHS) processing of slope (dip), aspect (dip direction), and elevation to reveal subtle topographic lineaments which may not be obvious in the unprocessed data are used to enhance digital elevation model (DEM) data from northwestern Nevada. This IHS method of lineament identification was applied to a mosiac of 12 square degrees using a Cray Y-MP8/864. Square arrays from 3 x 3 to 31 x 31 points were tested as well as several different slope enhancements. When relatively few points are used to fit the plane, lineaments of various lengths are observed and a mechanism for lineament classification is described. An area encompassing the gold deposits of the Carlin trend and including the Rain in the southeast to Midas in the northwest is investigated in greater detail. The orientation and density of lineaments may be determined on the gently sloping pediment surface as well as in the more steeply sloping ranges.

  13. Mechanistic Based DEM Simulation of Particle Attrition in a Jet Cup

    SciTech Connect

    Xu, Wei; DeCroix, David; Sun, Xin

    2014-02-01

    The attrition of particles is a major industrial concern in many fluidization systems as it can have undesired effects on the product quality and on the reliable operation of process equipment. Therefore, to accomodate the screening and selection of catalysts for a specific process in fluidized beds, risers, or cyclone applications, their attrition propensity is usually estimated through jet cup attrition testing, where the test material is subjected to high gas velocities in a jet cup. However, this method is far from perfect despite its popularity, largely due to its inconsistency in different testing set-ups. In order to better understand the jet cup testing results as well as their sensitivity to different operating conditions, a coupled computational fluid dynamic (CFD) - discrete element method (DEM) model has been developed in the current study to investigate the particle attrition in a jet cup and its dependence on various factors, e.g. jet velocity, initial particle size, particle density, and apparatus geometry.

  14. Modeling Particle Rolling Behavior by the Modified Eccentric Circle Model of DEM

    NASA Astrophysics Data System (ADS)

    Chang, Yi-Long; Chen, Tsung-Hsien; Weng, Meng-Chia

    2012-09-01

    This study proposes a modified eccentric circle model to simulate the rolling resistance of circle particles through the distinct element method (DEM) simulation. The proposed model contains two major concepts: eccentric circle and local rotational damping. The mass center of a circular particle is first adjusted slightly for eccentricity to provide rotational stiffness. Local rotational damping is adopted to dissipate energy in the rotational direction. These associated material parameters can be obtained easily from the rolling behavior of one rod. This study verifies the proposed model with the repose angle tests of chalk rod assemblies, and the simulated results were satisfactory. Simulations using other existing models were also conducted for comparison, showing that the proposed model achieved better results. A landslide model test was further simulated, and this simulation agreed with both the failure pattern and the sliding process. In conclusion, particle rolling simulation using the proposed model appears to approach the actual particle trajectory, making it useful for various applications.

  15. Simulation of Hydraulic and Natural Fracture Interaction Using a Coupled DFN-DEM Model

    SciTech Connect

    J. Zhou; H. Huang; M. Deo

    2016-03-01

    The presence of natural fractures will usually result in a complex fracture network due to the interactions between hydraulic and natural fracture. The reactivation of natural fractures can generally provide additional flow paths from formation to wellbore which play a crucial role in improving the hydrocarbon recovery in these ultra-low permeability reservoir. Thus, accurate description of the geometry of discrete fractures and bedding is highly desired for accurate flow and production predictions. Compared to conventional continuum models that implicitly represent the discrete feature, Discrete Fracture Network (DFN) models could realistically model the connectivity of discontinuities at both reservoir scale and well scale. In this work, a new hybrid numerical model that couples Discrete Fracture Network (DFN) and Dual-Lattice Discrete Element Method (DL-DEM) is proposed to investigate the interaction between hydraulic fracture and natural fractures. Based on the proposed model, the effects of natural fracture orientation, density and injection properties on hydraulic-natural fractures interaction are investigated.

  16. Robust 3D Quantification of Glacial Landforms: A Use of Idealised Drumlins in a Real DEM

    NASA Astrophysics Data System (ADS)

    Hillier, J. K.; Smith, M. S.

    2012-04-01

    Drumlins' attributes, such as height (h) and volume (V ), may preserve important information about the dynamics of former ice sheets. However, measurement errors are large (e.g., 39.2% of V within ±25% of their real values for the 'cookie cutter') and, in general, poorly understood. To accurately quantify the morphology of glacial landforms, the relief belonging to that landform must be reliably isolated from other components of the landscape (e.g. buildings, hills). A number of techniques have been proposed for this regional-residual separation (RRS). Which is best? Justifications for those applied remain qualitative assertions. A recently developed, novel method using idealised drumlins of known size (hin, V in) in a real digital elevation model (DEM) is used to quantitatively determine the best RRS technique, allowing general guidelines for quantifying glacial landforms to be proposed. 184 drumlins with digitised outlines in western Central Scotland are used as a case study. The NEXTMap surface model (DSM) is the primary dataset employed. A variety of techniques are then investigated for their ability to recover sizes (hr, V r). A metric, ɛ, is used that maximises the number of Hr/Hin values near 1.0 whilst giving equal weight to different drumlin sizes: a metric dominated by the large number of small drumlins is not desirable. For simplicity, the semi-automated 'cookie cutter' technique is used as a baseline for comparison. This removes heights within a drumlin from a DEM, cuts a hole, then estimates its basal surface by interpolating across the space with a fully tensioned bi-cubic spline (-T1). Metrics for h and V are ɛh = 0.885 and ɛV = 0.247. Other tensions do not improve this significantly, with ɛV of 0.245 at best, but using Delauney triangulation reduces ɛV to 0.206. Windowed 'sliding median' filters, which do not require heights within drumlins to be removed, attain a minimum ɛV of 0.470 at a best width of 340 m (-Fm340). Finally, even crudely

  17. DEM investigation on characteristics of rolling resistance for modelling particle shape

    NASA Astrophysics Data System (ADS)

    Zhou, Lunlun; Chu, Xihua; Xu, Yuanjie

    2017-06-01

    To examine the capability of rolling resistance to model the effects of particle shape, two sets of samples, composed of binary clumped particles and circular particles with rolling resistance, are tested in DEM simulation. The coefficient of rolling friction is estimated based on the energy dissipation. The effects of rolling resistance and particle shape on the shear strength, deformation behavior and non-coaxiality are compared. The numerical results show that rolling resistance reproduces well the effect of particle shape on the peak strength. However, other macro-properties, such as residual strength, elasticity modulus, poisson's ratio, dilatancy and non-coaxiality, introduced by rolling resistance both exist certain differences compared with the effect of particle shape. The discrepancies is thought to be due to the increasing compressibility of samples as the particle shape becomes more elongated, which cannot be reproduced by increasing rolling friction.

  18. A coupled DEM-DFN approach to rock mass strength characterization

    NASA Astrophysics Data System (ADS)

    Harthong, Barthelemy; Scholtes, Luc; Donze, Frederic

    2013-04-01

    An enhanced version of the discrete element method (DEM) has been specifically developed for the analysis of fractured rock masses [Scholtes L, Donze F, 2012]. In addition to the discrete representation of the intact medium which enables the description of the localized stress-induced damage caused by heterogeneities inherent to rocks, structural defects can be explicitly taken into account in the modeling to represent pre-existing fractures or discontinuities of size typically larger than the discrete element size. From laboratory scale simulations to slope stability case studies, the capability of this approach to simulate the progressive failure mechanisms occurring in jointed rock are presented is assessed on the basis of referenced experiments and in situ observations. For instance, the challenging wing crack extension, typical of brittle material fracturing, can be successfully reproduced under both compressive and shear loading path, as a result of the progressive coalescence of micro-cracks induced by stress concentration at the tips of pre-existing fractures. In this study, the dedicated DEM is coupled to a discrete fracture network (DFN) model to assess the influe