초록 ▼

A communications network, suitable, for example, for linking computer processors, is formed from a number of nodes and links. The nodes and links are configured as a multiplicity of directed trails. Each directed trail spans some only of the nodes, but in combination the directed trails span every n

A communications network, suitable, for example, for linking computer processors, is formed from a number of nodes and links. The nodes and links are configured as a multiplicity of directed trails. Each directed trail spans some only of the nodes, but in combination the directed trails span every node of the network. Packets are routed through the network by selecting the appropriate one of the directed trails which links the source node and destination node, and by outputting the packet at the source node onto the selected trail. The nodes throughout the network may switch between predetermined and prescheduled switching states, and a given trail may be selected by choosing appropriately the time slot in which the packet is put onto the network. The network may be a photonic network carrying optical packets.

대표청구항 ▼

A communications network, suitable, for example, for linking computer processors, is formed from a number of nodes and links. The nodes and links are configured as a multiplicity of directed trails. Each directed trail spans some only of the nodes, but in combination the directed trails span every n

A communications network, suitable, for example, for linking computer processors, is formed from a number of nodes and links. The nodes and links are configured as a multiplicity of directed trails. Each directed trail spans some only of the nodes, but in combination the directed trails span every node of the network. Packets are routed through the network by selecting the appropriate one of the directed trails which links the source node and destination node, and by outputting the packet at the source node onto the selected trail. The nodes throughout the network may switch between predetermined and prescheduled switching states, and a given trail may be selected by choosing appropriately the time slot in which the packet is put onto the network. The network may be a photonic network carrying optical packets. ct to the boat. 22. The system of claim 21, wherein one of the at least two phased arrays measures the motion of the boat relative to the bottom of the defined channel. 23. The system of claim 16, wherein the different frequencies are spaced apart at least by a factor of 2. 24. A method of measuring flow velocity of a river, the method comprising: mounting a Doppler sonar system on a boat wherein the sonar system comprises a first and a second acoustic transducer operating at different frequencies; streamlining the mounted sonar system so as to reduce its effect on the disturbance of the flow of the river; transmitting a first and a second acoustic signal into the river wherein the first signal is transmitted by the first transducer and the second signal is transmitted by the second transducer; and receiving and processing backscattered echoes of the first and second acoustic signals wherein the echo from the first signal is used to measure the flow velocity of the river within a first range and the echo from the second signal is used to measure the flow velocity of the river within a second range, wherein the backscattered echoes result in independent data that allow independent determination of the flow velocity at each of the first and second ranges and the first and second ranges are different. 25. The method of claim 24, further comprising traversing the river on the boat to measure a sectional profile of the river's flow velocity. 26. The method of claim 25, wherein one of the acoustic signals is used to measure boat's velocity relative to the bottom of the river. 27. The method of claim 24, wherein transmitting the first and second signals comprises transmitting the first signal at a first frequency and transmitting the second signal at a second frequency. 28. The method of claim 27, wherein the first frequency is in a range of approximately 300-600 KHz and the second frequency is in a range of approximately 1200-2400 KHz. 29. The method of claim 28, further comprising offsetting the motion of the boat from the measurement using the first frequency acoustic signal to determine the boat's motion relative to the bottom of the river. 30. The method of claim 24, wherein the first and second acoustic frequency signals are spaced apart at least by a factor of 2. 31. The method of claim 24, wherein the river is a man-made channel. 32. A method of measuring flow velocity of a river, the method comprising: mounting a Doppler sonar system on a boat wherein the sonar system comprises a phased array of transducers; streamlining the mounted sonar system so as to reduce its effect on the disturbance of the flow of the river; transmitting into the river at least one set of a plurality of acoustic beams formed by the phased array; receiving a plurality of backscattered echoes from the river; and processing the echoes to determine the flow velocity of the river wherein the plurality of acoustic beams from the phased array system permit measurement of the flow velocity independent of speed of sound in the water: wherein the plurality of backscattered echoes result in independent data that allow independent determination of the flow velocity at different, respective, depth ranges. 33. The method of claim 32, comprising traversing the river on the boat to measure a sectional pr