s ec in Software

Generate QR Code JIS X 0510 in Software s ec

Use the frame-relay map command to con gure manual resolution of PVCs. By default, broadcasts do not go across a manually resolved

Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website.

2 3 1

adjust motion characteristics without violating or adding to the constraints. The greater generality of this method can be easily grasped since nonrational B-splines are a special case of rational B-splines. The advantage of using rational B-splines will be illustrated in examples to follow.

Other Header Fields The data offset, also known as the header length, indicates the length of the TCP header in 32-bit words. This field also indicates where the actual user data begins, hence the name given to the field. The TCP header also contains a number of flags as follows:

1. Between the amide nitrogen and the a-carbon (angle of rotation = f) 2. Between the a-carbon and the carbonyl carbon (angle of rotation = c) 3. Between the carbonyl carbon and the amide nitrogen (no rotation) The third bond, the one between the carbonyl carbon and the amide nitrogen, cannot rotate. This is because the pair of nonbonded electrons on the nitrogen spends a portion of its time within that bond (so they are not entirely nonbonding once they are part of a peptide chain). This gives the bond somewhat of a double-bond character. This in turn prevents free rotation around the bond. It also means that the amide nitrogen, the carbonyl carbon, and the carbonyl oxygen must all lie within a plane. The other two bonds, however, allow free rotation, and we use the symbols f and c respectively to represent the angle of rotation between these bonds and a plane defined by the carbonyl group and the amide nitrogen. The N-Ca and Ca-C bonds themselves allow free rotation; however, other forces come into play to limit the possible values of f and c. Obviously all of the forces mentioned above can come into play (electric charge, hydrophobicity, etc.), but the two biggest contributors to the limits on f and c are (1) steric hindrances and (2) dipole-dipole interactions from adjacent peptide bonds. By taking these two forces into account, it is possible to calculate the potential energy (free energy) associated with every possible pair of f and c values. Steric hindrances alone will disallow many values of f and c depending on which amino acid side chains are considered. Taking dipole interactions into consideration refines the calculations. If we then plot a set of f and c for which the energy is within a particular range, we get a contour diagram that might look similar to Fig. 9-7. A f, c contour diagram is also called a ramachandran diagram for the biophysicist G. N. Ramachandran who invented it.

Track-at-Once A single-session method of writing one or more tracks to a recordable disc in which the table of contents and Lead-In area are added after the Program Area is completed. The disc is xed after the TOC and Lead-In are appended and no further tracks can be added. Discs created in this manner are not suitable for masters to use in mass replication. Compare to Discat-Once. Transfer Rate A measure of the speed at which data can be moved from one point to another. Transfer rates are generally expressed in terms of kilobytes per second. A quad-speed recorder can write data at the rate of 600 kilobytes per second. UDF Shortened form for Universal Disc Format. A random-access le system devised by OSTA for use on a variety of optical media, including CD-RW and DVD-ROM. UDF Bridge A form of UDF that also includes backwards compatibility to earlier devices that rely on ISO 9660. UltraWide SCSI A high-speed implementation of the SCSI standard that can achieve transfer rates up to 40MB per second using a 16-bit data path. Universal Product Code Abbreviated to UPC. A 13-digit catalog number that can be written to a disc s table of contents for identi cation. Not all CD recorders support writing of a UPC (sometimes referred to as EAN). VideoCD A variation of the CD-ROM standard that includes video data compressed

5