China
Africa
Explore chapters and articles related to this topic
The Internet
Published in Paul W. Ross, The Handbook of Software for Engineers and Scientists, 2018
The PING command (like TELNET and FTP) operates on an Internet host computer (as opposed to MAIL or NOTE, which use an individual user’s Internet address). The purpose of the PING command is to determine whether or not a specified host computer is operating and connected to the Internet. A typical use of the PING command would be PING acad.faindm.edu If the remote computer is up and connected, you might see a message similar to the following: Ping #1 response took 0.154 seconds. Successes so far 1. On the other hand, if you see a “time-out” message (e.g., “Ping #1 timed out”), either the remote (“host”) computer is not up, or the connection to it has failed. If you see an “unknown host” message, the domain name you specified does not exist.
Controlled System
Published in Christos N. Houmkozlis, George A. Rovithakis, End-to-End Adaptive Congestion Control in TCP/IP Networks, 2017
Christos N. Houmkozlis, George A. Rovithakis
Round trip time (RTT) [4], [106], [149], [157], also called round trip delay, is the time required for a packet to travel from a source to its corresponding destination and back again. On the Internet, an end user can determine the RTT from the IP address by pinging that address. Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol (IP) network and to measure the round trip time for messages sent from the originating host, to the destination computer. The RTT incorporates both propagation and queueing delay and depends on various factors including:
Basics of Networking in DP
Published in Surender Kumar, Dynamic Positioning for Engineers, 2020
The ping command can be helpful in ascertaining if the IP-level connectivity is good. If troubleshooting with the help of a ping command, it may be used to send a message which is known as an ICMP echo request to a target computer/device by using the device’s name or IP address. If a response is received back in time it confirms the connectivity and good working condition of all the components in the network between the two devices under test. A ping command may be initiated by using a command prompt commonly known as “cmd.exe”. (Figure 15.3).
Measuring the sound speed in deep-sea first sediment layer using a high-frequency submersible sub-bottom profiler: Method and sea trial application
Published in Marine Georesources & Geotechnology, 2022
Zhiguo Qu, Dapeng Zou, Mingguang Shan, Xinghui Cao, Yongqiang Xie
From the original echo data, we selected the data range ping 700 to ping 800 to apply the coherent pulse compression algorithm and used the attitude data provided by the manned DSV in the angular correction of the coherent pulse compression results using Equation (5). We obtained a sub-bottom profile of the deep-sea surface sediments in Figure 7a by combining the angle-corrected compression results of ping 700 to ping 800. Figure 7a shows the profile information of the deep-sea surface sediments. The two curves in the profile were clear and obvious. The first curve was the boundary between the seawater and the upper surface of the first sediment layer, and the second curve was the boundary between the lower surface of the first sediment layer and other sediment layer. The section between the two boundaries was the first sediment layer. Figure 7b shows a typical compression waveform of the ping 750. As shown in the compression waveform, the first and second main peaks were clearly visible, and the width of the two main peaks was complete without any superimposition. Therefore, based on the verification test, the time difference between the first main peak and the second main peak in the ping 750 compression waveform was the accurate time it took for the sound wave to propagate in the first sediment layer. Therefore, the accurate travel time of sound wave in the first sediment layer could be extracted according to the longitudinal axis information shown in Figure 7a.
Long-term observation of current at the mouth of Tokyo Bay
Published in Coastal Engineering Journal, 2022
Current velocity is measured using an acoustic Doppler current profiler (ADCP; Workhorse Mariner 300 kHz, Teledyne RD Instruments Inc., California). The ADCP is mounted on the bottom of the hull of the ferry. The downward-looking ADCP measures the current velocity profile in 4-m layers from the depth of 7.2 m beneath the hull to the maximum range of this ADCP, i.e. approximately 100 m, (Figure 1c). Bottom tracking is used to measure the ship’s velocity with accuracy of a few millimeters per second (Teledyne RD Instruments 2011). The standard deviation of the current velocity profile is 1.0 cm/s, which is reduced from the standard deviation of 3.6 cm/s for a single ping using 12 pings with a 20-s sampling interval. The current velocity profile is calculated by subtracting the ship’s velocity from the measured current velocity in post-processing procedures. Quality control for the current velocity of the water is performed using two standard processes and our original data-rejection process (Supplemental Information A).
Illuminating centimeter-level resolution stratum via developed high-frequency sub-bottom profiler mounted on Deep-Sea Warrior deep-submergence vehicle
Published in Marine Georesources & Geotechnology, 2021
Xinghui Cao, Zhiguo Qu, Binjian Shen, Hanyu Zhang
In order to verify the effectiveness of layered structure and thickness measured by HFSBP, a laboratory test for the HFSBP in the anechoic tank was performed, as shown in the left of Figure 11. An acrylic sample block was dipped vertically into the anechoic tank as well as using a mechanical fixture to illuminate the HFSBP transducer on the acrylic block along the horizontal direction. The size of the sample block was 30 cm × 30 cm × 10 cm, in which 10 cm was the thickness direction, parallel with the direction of the HFSBP illumination. Under the same acoustic parameters setting as in deep-sea dives, sound waves were transmitted and received with data logging. The single ping curve formed by pulse compression processing is shown in the right of Figure 11. The strong scatters marked by the two green points are the positions of the first and second layers of the acrylic sample. The sound speed in the acrylic sample was 2692 m/s according to the manufacturer’s instructions, and then the thickness between two layers calculated through the HFSBP single ping curve was 10.68 cm, which was very close to the actual depth of 10 cm of the sample. The experiment was repeated 20 times, and the measurement results were highly consistent with the variance of 0.001. This experiment verified the layered ability and the thickness measurement stability of the self-developed instrument HFSBP.