Binary code

Figure 2-64. How an excerpt from a binary code could appear, ifonly -NHj and C=0 are available In the fragmenl libraiy.

Addition of two numbers in binary code. Note the carryover in the left-most column caused by adding two ones. 

There is an electronic circuit called a flip-flop. It consists of two transistors connected in such a way that, if a voltage is applied, one side of the circuit becomes active and the other side not if a second voltage is applied, the circuit flips so that the active side becomes inactive and vice versa. Thus, just as with a conventional switch for which one touch puts it on and a second touch turns it off, one touch of the flip-flop turns it on and a second touch turns it ojf. Addition of two binary numbers now becomes possible. Suppose we want to add 2 -(- 1 (= 3 decimal). First, the numbers must be converted into binary code (10 and 01) and these become switch settings in the machine, but we need four switches so that 10 becomes on, off and 01 becomes off, on (Figure 42.6). 

If the first pair of switches is examined, one is off and the other on, and the result of touching each must be a resulting on (off-on and on-off, giving a total of on). For the other pair, exactly the opposite sequence is present but the net result is on. As far as the machine is concerned, the result is on, on, which in binary code is 11 and in decimal code is 3, the correct answer. Therefore, to get the machine to add in binary, it is necessary to have a switch for each power of two that we want. The number 2 is 64 (decimal) and, to represent any number up to 63, we must have seven switches (seven flip-flop circuits), viz., 2, 2, 2, 2, 2 , and zero. In computer jargon, these... 

In addition, most devices provide operator control of settings for temperature and/or response slope, isopotential point, zero or standardization, and function (pH, mV, or monovalent—bivalent cation—anion). Microprocessors are incorporated in advanced-design meters to faciHtate caHbration, calculation of measurement parameters, and automatic temperature compensation. Furthermore, pH meters are provided with output connectors for continuous readout via a strip-chart recorder and often with binary-coded decimal output for computer interconnections or connection to a printer. Although the accuracy of the measurement is not increased by the use of a recorder, the readabiHty of the displayed pH (on analogue models) can be expanded, and recording provides a permanent record and also information on response and equiHbrium times during measurement (5). 

S Sun, PD Thomas, KA Dill. A simple protein folding algorithm using a binary code and secondary structure constraints. Protein Eng 8 769-778, 1995. 

C/tarac[Pg.110]

EBCDIC (Extended Binary Coded Decimal Interchange Code)... 

Coding and Decoding. Ten-bit binary codes are used to transmit the information in most techniques. In one technique, the maximum reading to be transmitted is divided ten times. In a word, each bit has the value corresponding to its rank. 

The pulses are used to transmit deviation data from 0° to 90° with a 45, 22.5, 11.25, etc., sequence binary code of 10 bits. What is the transmission accuracy Give the binary number for 27.4°. 

Theorem 4-4 can now be used to obtain a simple relationship between tire entropy of a source and the minimum average length of a set of binary code words for the source. 

The initial data are binary coded in form of a bit sequence (bit string4). Start values of the variables x, x2,..., xm could be, e.g., 011001011,100101100,. ..,010010101. This initial population is undertaken an evolution process such as schematically represented in Fig. 5.8. 

In early work, GA strings were binary coded. Computer scientists are comfortable with binary representations and the problems tackled at that time could be easily expressed using this type of coding. Binary coding is sometimes appropriate in scientific applications, but it is less easy to interpret than alternative forms, as most scientific problems are naturally expressed using real numbers. 

Recently, Jung et al. [42] developed two artificial neural network models to discriminate intestinal barrier-permeable heptapeptides identified by the peroral phage display experiments from randomly generated heptapeptides. There are two kinds of descriptors one is binary code of amino acid types (each position used 20 bits) and the other, which is called VHSE, is a property descriptor that characterizes the hydrophobic, steric, and electronic properties of 20 coded amino acids. Both types of descriptors produced statistically significant models and the predictive accuracy was about 70%. 

Fig. 1. Median partitioning and compound selection. In this schematic illustration, a two-dimensional chemical space is shown as an example. The axes represent the medians of two uncorrelated (and, therefore, orthogonal) descriptors and dots represent database compounds. In A, a compound database is divided in into equal subpopulations in two steps and each resulting partition is characterized by a unique binary code (shared by molecules occupying this partition). In B, diversity-based compound selection is illustrated. From the center of each partition, a compound is selected to obtain a representative subset. By contrast, C illustrates activity-based compound selection. Here, a known active molecule (gray dot) is added to the source database prior to MP and compounds that ultimately occur in the same partition as this bait molecule are selected as candidates for testing. Finally, D illustrates the effects of descriptor correlation. In this case, the two applied descriptors are significantly correlated and the dashed line represents a diagonal of correlation that affects the compound distribution. As can be seen, descriptor correlation leads to over- and underpopulated partitions.

Schmidt et al. suggested isotopomer distribution vectors (IDV) to quantitatively describe distributions of positional isotopomers, whereby the elements of an IDV contain molar fractions of single positional isotopomers [14]. The indexing of positional isotopomers as elements of an IDV is based on the binary code with ones for labeled and zeros for non-labeled carbons following the standard rules of numbering the carbons within a molecule. The positional isotopomers in Fig. (1) are ordered in this way. The sum of all elements in the IDV equals 1. The IDV of pyruvate can serve as an example (Eq. 1). 

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