Abstract: Systems and methods include a wing tool configured to be operable from work vessel(s), the wing tool including thrusters capable of fluidizing sediments from a first seabed location and moving it to a second seabed location, the second seabed location including a trench or differently shaped collection sump previously made by the wing tool and/or an extraction pump. The extraction pump operates from a second work vessel having sufficient capacity to pump fluidized sediments from the trench. Certain systems include a separation unit that separates sand from silts and clays and water from collected sediment. Systems and methods for reclamation of reservoirs, moving sand waves, for pre-trenching and/or recovering marine pipelines and cables, for removing cover from marine archaeological sites and for disposing of contaminated bottom materials in an environmentally acceptable manner.

Abstract: A scheme for altering checking information in a message packet intended to be transmitted between computers is described. In this scheme, when an information portion of the packet is altered, checking bits contained in the packets are altered in dependence only on the set of checking bits in the message packet before modification of the information portion and on the modifications to the information portion. Thus, it is not necessary to generate new checking bits from a modified information portion.

Abstract: A method of routing messages through a network is described in which a message packet is dispatched with two node indicators through the network including a succession of routing switches. When the message packet reaches a routing switch identified by the first node indicator, that routing switch deletes the first node indicator and the second node indicator is then used to route the message packet through the network.

Abstract: A communications device, particularly but not exclusively for use with a routing circuit, transmits and receives message packets. An output buffer converts data and flow-control information into a plurality of bit sequences and transmits them at a predetermined frequency. An input buffer decodes informing sequences into data items and flow control information. The input buffer can store the data items and count them and transmit flow control information to the output buffer.

Abstract: A method of encoding data for transmission between computer devices is disclosed in which data is encoded into a plurality of sequences, each sequence containing an equal number of ones and zeros and being of a predetermined bit length. There is a finite set of the permutations of equal numbers of ones and zeros in that predetermined bit length. One subset of the finite set is selected for use as data codes and a second subset is selected for use as control codes.

Abstract: A routing switch includes an input for receiving serial packets from a source node in a computer network, a plurality of outputs each designating a respective range of destination node identifications, switch circuitry for selectively interconnecting said input to a selected one of said outputs and header reading circuitry for reading the header portion of a packet received at the input prior to receiving all of the packet. The header reading circuitry is coupled to the switch circuitry to connect to said input one of said outputs having a node identification range including the node identification of said header portion.There is also provided a computer network, having a plurality of computer devices and at least one routing switch, and a method of routing messages through such a network.

Abstract: A routing switch includes an input for receiving serial packets from a source node in a computer network, a plurality of outputs, switch circuitry for selectively interconnecting said input to a selected one of said outputs and header reading circuitry for reading the header portion of a packet received at the input prior to receiving all of the packet. The switch also has a random header generator which produces header portions generated at random which are then read by the header reading circuitry. The header reading circuitry is coupled to the switch circuitry to connect to said input one of said outputs in dependence on said random header. The random header portion is then discarded at the routing switch identified thereby to reveal the original header.