In this thesis, we propose a systematic code for correcting t = 1 insertion/deletion errors of the character ”0” that can occur between any two consecutive 1’s in a binary string. The code requires balanced input strings, where each word of length n contains ⌈n/2⌉ 0’s and ⌊n/2⌋ 1’s. This...
This project aims at implementing Indexing for Web 2.0 Applications. Ajax applications consist of a set of states which are generated by the user through actions such as click, focus, blur etc. events. By saving these DOM states we can index information obtained from dynamically generated web content. To prevent...
Concurrent error detection (CED) is the detection of errors or faults in a circuit or data path concurrent with normal operation of that circuit. The general approach for CED is to calculate a check symbol for the inputs to the circuit under operation, predict the check symbol that will result...
The use of Totally Self-Checking Checkers in the design of highly reliable systems has significant advantages. It allows errors to be detected upon occurance without testing whether the error is caused by a permanent or an intermittent fault. The TSC circuit provides an error indication whenever the input is not...
An extensive theory of symmetric error control coding has been developed in the last few decades. The recently developed VLSI circuits, ROM, and RAM memories have given an impetus to the extension of error control coding to include asymmetric and unidirectional types of error control. The maximal numbers of unidirectional...
The asymmetric nature of bit errors in several practical applications provides grounds for efficient error control techniques. The Z-channel model and special classes of codes like asymmetric error detection codes and t-asymmetric error correcting/d-asymmetric error detecting codes can be successfully used in ARQ protocols for feedback error control enhancement. This...
In some practical systems, most of the errors are of 1 → 0 type and 0 → 1
errors occur very rarely. In this thesis, first, the capacity of the asymmetric
channel is derived. The capacity of the binary symmetric channel (BSC) and the
Z-channel can be derived from this...
Various problems related to systematic error-detecting
and error-correcting unidirectional codes are discussed.
Systematic codes with r check bits are the main topic of
the thesis. Classes of codes are presented which work for
specific numbers of information bits and then a class of
codes is given which detects the same...
In diversity combining automatic repeat request (ARQ), erroneous packets are combined together forming a single, more reliable, packet. In this thesis, we give a diversity combining scheme for the m-ary unidirectional channel. A system using the given scheme with a t-unidirectional error detecting code is able to correct up to...