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Security Challenges and Solutions in IoT Networks for the Smart Cities
Published in Mohammad Ayoub Khan, Internet of Things, 2022
Highlighting the need for lightweight detection, the authors in [84] developed an intrusion detection system (IDS) for IoT devices aiming to detect multiple types of DDoS attacks. They have chosen various host-based features regarding the Network Time Protocol (NTP) servers. NTP is a network protocol for clock synchronization between computer systems over packet-switched, variable-latency data networks. The host features chosen were delay time, response delay time, and offset clock. For the detection of DDoS attack, the mean and standard deviation are calculated and the central limit theorem is used to differentiate between legitimate and malicious DDoS traffic. In their experiments, the attack duration lasted for approximately 20 minutes. In their results, they report the TP rate being 100% and the FP rate being 16.66%.
Internet Security and Firewall Policies
Published in Steven F. Blanding, Enterprise Operations Management, 2020
In addition to those protocols previously discussed are the following: Serial Line Internet Protocol. The serial line Internet protocol (SLIP) is used to exchange IP traffic with a device, usually a workstation, that is running the proper protocols but without a separate address. It is used to connect workstations to hosts or to Internet service providers through the dial-switched network. It is analogous to an extension cord or a remote.Point-to-Point Protocol. The point-to-point protocol (PPP) is similar to Serial Line Internet Protocol, but is associated with leased lines. It is usually used to connect a single system to a boundary or “edge” node.Network Time Protocol. The network time protocol (NTP) is used to set and synchronize the system clocks of Internet nodes. It is able to synchronize all systems in a network to within milliseconds of each other, i.e., to within the accuracy and precision of the system clocks themselves.Secure Protocols. Recently, secure versions of these protocols have been specified, and reference implementations of these protocols are available for Unix systems.
Time Measurement
Published in John G. Webster, Halit Eren, Measurement, Instrumentation, and Sensors Handbook, 2017
Client computers (which can also be servers to computers at higher stratums) issue time requests to an NTP server via TCP/IP port 123. They receive a data packet that contains a UTC time code and other time stamps that indicate when the request was made, when it arrived, and when the packet was sent. This information is used to calibrate the path, to synchronize the client’s clock, and to steer the client’s clock between synchronizations. The performance of NTP depends upon the client hardware and software and network conditions and varies widely, but uncertainties of less than a millisecond have been demonstrated under optimal conditions. A typical computer, running the Microsoft Windows operating system on the public Internet, can usually keep time within 1 or 2 s of UTC with one NTP synchronization request per week.
Timing Synchronization System on RF-Driven Neutral Beam Injection System
Published in Fusion Science and Technology, 2022
Y. Li, C. D. Hu, Y. Z. Zhao, Q. L. Cui, X. L. Shu, Y. H. Xie, W. Liu
Network time synchronization refers to synchronizing the clock of each node to a stable and high-precision time source through the network so that the whole system can achieve clock consistency. At present, the network clock synchronization system generally uses the Network Time Protocol (NTP); the synchronization accuracy can reach only millisecond level. NTP is a protocol based on TCP/IP and User Data Protocol (UDP) network transmission and adopts the method of application layer synchronization for network time synchronization. The synchronization protocol is mainly defined by RFC 1305, “Network Time Protocol (Version 3) Specification, Implementation and Analysis.” It can solve the time synchronization problem between devices on complex network topologies. For some systems with low time synchronization accuracy requirements, using NTP for time synchronization is more economical and practical, and the implementation method is relatively simple.
The instructor assistant system (iASSYST) - utilizing eye tracking for commercial aviation training purposes
Published in Ergonomics, 2020
David Rudi, Peter Kiefer, Martin Raubal
The training took place in an A320 FFS (see Figure 1), and instructors used iASSYST on a PC in a debriefing room (not depicted). Figure 2 shows the iASSYST dialog which the instructors worked with. It includes a video and audio recording of the cockpit, a close-up video of the two most important cockpit displays, the current aircraft state as flight parameters, a graphical representation of the relevant Areas Of Interest (AOIs), and the pilot gaze overlaid onto the videos and AOIs. The two most important flight displays are the primary flight and navigation display, which are utilised by pilots to fulfill two of the key tasks of flight, i.e., aviating and navigating (Wickens 2008). The flight parameters and AOIs were determined with the SMEs. A recording software received and recorded all the incoming data, which were later analysed with iASSYST. All data were automatically synchronised using the Network Time Protocol (NTP) (Mills 2011) and timestamps. The NTP allows synchronising the local timestamps of different PCs across a network. If the SME and experimenter noticed a synchronisation error, they could use a synchronisation dialog of iASSYST to manually align the timestamps. Two PCs and an eye tracker were built into the FFS. We chose the SmartEye Pro remote eye tracker (SmartEye AB 2019) after a thorough evaluation of alternatives. The system was composed of 4 cameras and 2 illuminators and ran at a frequency of 60 Hz. It was calibrated to provide an eye-tracking accuracy of around 1° for the two most important cockpit displays.