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Practical Solutions
Published in Andy Bailey, Network Technology for Digital Audio, 2013
IP is a network layer or layer-3 protocol. It provides the actual addressing that allows packets to be routed to the correct destination. IP addresses are made up of four 8-bit bytes, called octets, and these are often written in decimal format for simplicity. To illustrate this, it is easy to see that this binary address notation: 10000111.10100101.00100011.11110000is more easily written and understood as: 135.165.35.240
Number Systems, Operations, and Codes
Published in Syed R. Rizvi, Microcontroller Programming, 2016
Before we go further, it is important to define terms such as bit, nibble, byte, and octet. We will be using these terms frequently from now onward. A binary digit, abbreviated as bit, is the smallest unit of information in digital computing. In the binary world, a single bit can hold only one of two values: 0 or 1. More meaningful information is obtained by combining consecutive bits into larger units. For example, a nibble is composed of 4 consecutive bits. Since a nibble contains 4 bits, there are sixteen (24) possible values, so a nibble corresponds to a single hexadecimal digit. For example, F16 = 11112. A byte is also an ordered collection of bits. The size of a byte is typically hardware dependent, but the modern de facto standard is 8 bits, as this is a convenient power of 2. The term octet explicitly denotes a sequence of 8 bits because of the ambiguity associated with the term byte, and is widely used in digital computing. In short, a nibble is half a byte (octet). A byte (octet) is represented by two hexadecimal digits; therefore, it is common to display a byte of information as two nibbles. Thus, patterns like 3E and D2 are possible in a hexadecimal system, and a number like BF might not even look like a number at all. However, this system of writing binary numbers where every 8-bit byte becomes a two-digit hexadecimal (base 16) code only takes two print characters to write. This is a more compact way of writing the binary contents of a computer memory. In the hexadecimal system, 16 keys are needed for a keyboard, but the striking rate is only one-fourth of that required with a binary keyboard. Group Discussion: Why is the striking rate with hexadecimal keyboard only one-fourth of that required with a binary keyboard?
Introduction
Published in P. S. Neelakanta, ATM Telecommunications, 2018
Digital communication is rendered by transmissions of a series of zeroes and ones. That is, binary format is used in most instances to represent the information flow in digital communications. The signal elements used, namely, “ones” and “zeros” are referred to as bits (binary digits). A set of 4 bits is termed a nimble and 8 bits constitute a byte (or an octet).
Generative adversarial networks for network traffic feature generation
Published in International Journal of Computers and Applications, 2023
Tertsegha J. Anande, Sami Al-Saadi, Mark S. Leeson
Previously, Ring et al. [16] used the Wasserstein GAN with Gradient Penalty (WGAN-GP) model with an incorporated Two Time-Scale Update Rule (TTUR) to generate and transform flow-based network traffic. Their approach, Flow-Based Network Traffic Generation GAN, converted categorical features to binary attributes while learning vector representations using the IP2Vec similarity measure [16]. To test the WGAN-GP, three methods to investigate synthetic feature generation were employed. In the first, IP addresses and Port numbers were transformed to categorical features, while other categorical features were normalized to the interval [0,1], which unfortunately produced unwanted similarities and significant errors between them. The second method mapped each octet of an IP address to an 8-bit binary representation producing a 32-bit representation, port numbers were transformed to a 16-bit representation, bytes and packets to a limited length representation of 32-bits, and duration normalized to [0,1]. The approach successfully generated flow-based network traffic including previously unseen IP addresses and port numbers. The third method embedded categorical features into an m-dimensional continuous feature space for input, generated flows mapped to embeddings and re-transformed to their original space, thus surpassing the other two approaches in performance with an average evaluation of 99.83%. This model only accepted numerical features for training as all categorical and non-numerical features were transformed or embedded during data pre-processing and prior to training.
Compressive fatigue characteristics of octet-truss lattices in different orientations
Published in Mechanics of Advanced Materials and Structures, 2022
Yifan Li, Martyn Pavier, Harry Coules
In compression fatigue, the main characteristic of plastic lattice structures is gradual strain accumulation, which also leads to the physical shortening of specimens [11, 18, 19]. The relationship between accumulated strain and the number of fatigue cycles N for octet-truss lattices in three different orientations is plotted on a linear scale in Figure 6. Accumulated strain versus cycle curves for all orientations octet-truss lattices exhibit three-stage fatigue behavior. In the first stage, the strain changes rapidly within a few cycles, and then the strain accumulation shows a relatively constant and minimal change in the second stage. At the final stage, the strain accumulates very rapidly and the specimen fails within a limited number of cycles. Octet-truss lattice in orientation Z normally has larger fatigue cycles than orientations X and Y specimens under the same stress level. The present study also shows the fatigue life of octet-truss lattices are largely determined by stage II.
Development of building thermal environment emulator to evaluate the performance of the HVAC system operation
Published in Journal of Building Performance Simulation, 2019
To remotely evaluate the operation, it is useful for the emulator system to be able to communicate using the BACnet/IP, which requires specification of the network addresses of the BACnet devices. Each network address is given as a four-octet IP address followed by a two-octet UDP port number. Normally, 47808 (“xBAC0” in hexadecimal) is used as the port number, which is identified by the IP address. However, when multiple BACnet devices are virtually coexistent within a single software package such as an emulator, assigning different IP addresses is difficult, in which case it is permissible to identify the BACnet device by making the port number unique (ASHRAE 2016). The IP addresses of the approximately 100 BACnet devices included in the proposed emulator are equivalent to those of the computer on which the emulator runs and are identified by the port number.