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Usuari:Parlance/proves

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Taula òrbites modifica 

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Gèneres de cultura i entreteniment modifica

Articles sobre gèneres:

Categorització:

Genre modifica

Un gènere o "tipus", del llatí genus Genre (; from French genre [ʒɑ̃ʁ(ə)], "kind" or "sort", from Latin genus (stem gener-), Greek γένος, gés) is any category of literature, music, or other forms of art or entertainment, whether written or spoken, audio or visual, based on some set of stylistic criteria. Genres form by conventions that change over time as new genres are invented and the use of old ones is discontinued. Often, works fit into multiple genres by way of borrowing and recombining these conventions.

Genre began as an absolute classification system for ancient Greek literature. Poetry, prose, and performance each had a specific and calculated style that related to the theme of the story. Speech patterns for comedy would not be appropriate for tragedy, and even actors were restricted to their genre under the assumption that a type of person could tell one type of story best. In later periods genres proliferated and developed in response to changes in audiences and creators. Genre became a dynamic tool to help the public make sense out of unpredictable art. Because art is often a response to a social state, in that people write/paint/sing/dance about what they know about, the use of genre as a tool must be able to adapt to changing meanings. In fact as far back as ancient Greece, new art forms were emerging that called for the evolution of genre, for example the tragicomedy.

Jon Bellion modifica

Jonathan Bellion (Long Island, Nova York, 26 de desembre de 1990), conegut amb el seu nom artístic Jon Bellion és un cantant, compositor i productor estatunidenc.

spacewire modifica

L'SpaceWire és una xarxa de comunicació de naus espacials basada en l'estàndar IEEE 1355 de comunicacions. És coordinat per l'Agència Espacial Europea en col·laboració amb la NASA, la JAXA i l'RKA.

En el si d'una xarxa SpaceWire, els nodes estan conectats a través d'enllaços en sèrie punt a punt, de baix cost, baixa latència

Within a SpaceWire network the nodes are connected through low-cost, low-latency, full-duplex, 

point-to-point serial links and packet switching wormhole routing routers. 
SpaceWire covers two (physical and data-link) of the seven layers of the OSI model for communications.

Architecture modifica

SpaceWire's modulation and data formats generally follow the data strobe encoding - differential ended signaling (DS-DE) part of the IEEE Std 1355-1995. SpaceWire utilizes asynchronous communication and allows speeds between 2 Mbit/s and 400 Mbit/s. DS-DE is well-favored because it describes modulation, bit formats, routing, flow control and error detection in hardware, with little need for software. SpaceWire also has very low error rates, deterministic system behavior, and relatively simple digital electronics. SpaceWire replaced old PECL differential drivers in the physical layer of IEEE 1355 DS-DE by low-voltage differential signaling (LVDS). SpaceWire also proposes the use of space-qualified 9-pin connectors.

SpaceWire and IEEE 1355 DS-DE allows for a wider set of speeds for data transmission, and some new features for automatic failover. The fail-over features let data find alternate routes, so a spacecraft can have multiple data buses, and be made fault-tolerant. SpaceWire also allows the propagation of time interrupts over SpaceWire links, eliminating the need for separate time discretes.

Uses modifica

SpaceWire is used worldwide.[1] Its use began primarily in ESA projects, but it is currently used by NASA, JAXA, RKA, and many other organizations and companies. Some NASA projects using it include the James Webb Space Telescope, Swift's Burst Alert Telescope, the Lunar Reconnaissance Orbiter, LCROSS, the Geostationary Operational Environmental Satellite (GOES-R), and the SCaN Testbed, previously known as the Communications, Navigation, and Networking Reconfigurable Testbed (CoNNeCT). It has also been selected by the United States Department of Defense for Operationally Responsive Space. SpaceWire initiatives are being coordinated between several Space Agencies in the frame of CCSDS in order to extend its communication model to the Network and Transport Layers of the OSI model.

SpaceWire supports highly fault-tolerant networks and systems, which is one reason for its popularity.[2]

Protocols modifica

The ESA has a draft specification in place for the Protocol ID.

The following Protocol ID's have been assigned in ECSS-E-ST-50-11:

  • 1: Remote Memory Access Protocol (RMAP)
  • 2: CCSDS Packet Transfer Protocol
  • 238: Proposal for Reliable Data Delivery Protocol (RDDP) (used on GOES-R)
  • 239: Serial Transfer Universal Protocol (STUP) (Used on SMCS-332 ASIC)

References modifica

  1. ↑ "Who Uses SpaceWire?".
  2. ↑ Dr Barry M Cook; Paul Walker. "Ethernet over SpaceWire - software issues". p. 2.

External links modifica

Plantilla:External links

Commercial providers of SpaceWire equipment:

SpaceWire IP Cores:

Articles:


proves modifica

Roger A. Broucke (25 de març de 1932 - 21 de juny de 2005) va ser un enginyer aerospacial conegut per les seves solucions del problema dels tres cossos. Després de treballar en aplicacions pràctiques de mecànica orbital en el Jet Propulsion Laboratory, va exercir com a professor a la Universitat de Texas a Austin.

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