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Wyszukujesz frazę "Johnson, G. W." wg kryterium: Autor


Wyświetlanie 1-4 z 4
Tytuł:
Sharing ships’ weather data via AIS
Autorzy:
Tetreault, B.
Johnson, G. W.
Powiązania:
https://bibliotekanauki.pl/articles/116768.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
AIS Assisted Services
weather data
Automatic Identification System (AIS)
AIS Application-Specific Message (ASM)
National Transportation Safety Board’s (NTSB)
Voluntary Observing Ship (VOS)
National Oceanic and Atmospheric Administration (NOAA)
U.S. Army Corps of Engineers (USACE)
Opis:
In the aftermath of the sinking of the US-flagged containership El Faro in October 2015, one of the U.S. National Transportation Safety Board’s (NTSB) recommendations was for the National Oceanic and Atmospheric Administration (NOAA) to explore increasing the collection of weather data from ships in order to improve the weather forecast products that they distribute. Currently NOAA runs the Voluntary Observing Ship (VOS) program, where ships voluntarily submit weather observations to NOAA. However, only a small fraction of the thousands of vessels sailing worldwide participate in this program, and VOS weather observations are submitted infrequently, typically four times per day via a mainly manual process. One method being explored to automate and increase the frequency of data submittal is by using the existing Automatic identification System (AIS) equipment installed aboard vessels. Most commercial ships (in particular those subject to the International Maritime Organization's (IMO) Safety of Life and Sea (SOLAS) convention) have a Class A AIS transceiver installed to comply with mandatory carriage requirements. Many vessels not required to carry AIS equipment voluntarily install AIS transceivers (either Class A or B). All of these AIS transceivers (except for the Class B “CS”) can be used to transmit an AIS message 8 (broadcast binary message) by sending the transceiver an appropriately formatted NMEA sentence (BBM). Weather data can be embedded in an AIS application-specific message (ASM) carried by the AIS message 8 and automatically transmitted by the ship. This transmission can be received by terrestrial AIS stations (when in range) or by satellite AIS receivers. The AIS weather data can then be converted into the appropriate format and forwarded to the weather forecasting offices for use in models and weather predictions. This data may also be of use to other researchers monitoring climate change or other environmental factors. By leveraging this existing base of AIS transmitters, the volume of weather data being sent to weather forecast offices and others could be greatly increased. The U.S. Army Corps of Engineers (USACE) and U.S. Maritime Administration (MARAD) have been exploring the feasibility of this concept. Following a simple bench test performed by Alion Science in September 2018, an initial proof-of-concept was tested aboard the MARAD vessel Cape Wrath while moored in Baltimore in October 2018. After this successful demonstration, a prototype was installed on the Massachusetts Maritime Academy training ship TS Kennedy during her training cruise Jan-Feb 2019. During this cruise, the AIS equipment aboard the ship transmitted weather data at 3-minute intervals. Several different ASM formats were tested, including two developed specifically for this test to improve satellite reception. This report will discuss the concept, the demonstrations, and the results to date including the efficacy of the various ASM formats.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2020, 14, 1; 143-150
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Pennsylvanian xenacanth chondrichthyans from the Swisshelm Mountains, Arizona, USA
Autorzy:
Johnson, G.D.
Thayer, D.W.
Powiązania:
https://bibliotekanauki.pl/articles/21790.pdf
Data publikacji:
2009
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
vertebrate
fauna
xenacanth chondrichthyan
chondrichthyan
Swisshelm Mountains
Arizona
USA
Chondrichthyes
Xenacanthiformes
Bransonelliformes
Orthacanthus
Triodus
Bransonella
Opis:
Three genera of xenacanths, based on isolated teeth, occur in the lepospondyl (amphibian)−dominated fauna from the upper Black Prince Limestone (late Bashkirian). Orthacanthus donnelljohnsi sp. nov. teeth, with carinae lacking serrations on the compressed principal cusps, and only one intermediate cusp, represent both adult and juvenile teeth. Heterodonty occurs in both adult and juvenile dentitions. The absence of serrations is unique among Pennsylvanian species of Orthacanthus. Teeth with often highly asymmetrical bases with an aborally−flexed lingual marginal flange (= anterolingual shelf) and a single intermediate cusp are assigned to Triodus elpia sp. nov. A central foramen occurs in the base, unlike most other species; the moderately compressed principal cusps bear generally straight cristae. They represent the first reported occurrence of Triodus in the Paleozoic of North America. Five teeth, with cristae extending from the cusps onto their bases, belong to Bransonella. Two are questionably assigned to Bransonella nebraskensis, one to B. ?lingulata with its labio−lingually elongated apical button and smaller than normal intermediate cusp, and one each to Bransonella sp. “A” and “B”. Bransonella sp. “A” has a base wider (labio−lingual) than long, the reverse of the other Bransonella teeth. Bransonella sp. “B” is distinctly different, as it lacks an intermediate cusp (as in some B. lingulata teeth), and the basal tubercle is beneath one of the cusps (with no evidence of deformity).
Źródło:
Acta Palaeontologica Polonica; 2009, 54, 4
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femtosecond X-ray Absorption Spectroscopy οf a Light-Driven Spin-Crossover Process
Autorzy:
Milne, C.
Pham, V.
Gawelda, W.
Nahhas, A.
van der Veen, R.
Johnson, S.
Beaud, P.
Ingold, G.
Borca, C.
Grolimund, D.
Abela, R.
Chergui, M.
Bressler, Ch.
Powiązania:
https://bibliotekanauki.pl/articles/1539083.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
75.30.Wx
Opis:
Understanding the initial steps during ultrafast molecular reactions involving large spin state changes is a vital goal in structural dynamics research. These involve knowledge of the geometric structure of the system. Ultrafast X-ray absorption spectroscopy with 50-100 picosecond time resolution establishes the geometric structure of the short-lived (τ = 0.6 ns) high spin state. Here we focus on time-resolved X-ray absorption studies with 160-200 fs temporal resolution to monitor the structural evolution in this spin-conversion process.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 391-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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