795 research outputs found
Construction of m-Repeated Burst Error Detecting and Correcting Non-binary Linear Codes
Error correcting codes are required to ensure reliable communication of digitally encoded information. One of the areas of practical importance in which a parallel growth of the subject error correcting codes took place is that of burst error detecting and correcting codes. The nature of burst errors differs from channel to channel depending upon the behavior of channels or the kind of errors which occur during the process of transmission. The rate of transmission is efficient if the number of parity-check digits are as minimum as possible. It is usually not possible to give the exact number of parity-check digits required for a given code. However, bounds can be obtained over the number of parity-check digits. An upper bound for a linear code capable of detecting/ correcting burst errors or its variants is many a times established by the technique used to establish Varsharmov-Gilbert-Sacks bound by constructing a parity-check matrix for the requisite code. This technique not only ensures the existence of such a code but also gives a method for constructing such a code. The synthesis method using this technique is cumbersome and to the best of our knowledge, there is no systematic way to construct a parity-check matrix for a burst error correcting non-binary linear code. Extending the algorithm for binary linear codes given by the authors to non-binary codes, the paper proposes a new algorithm for constructing a parity-check matrix for any linear code over GF(q) capable of detecting and correcting a new kind of burst error called `m-repeated burst error of length b or less\u27. Codes based on the proposed algorithm have been illustrated
Repeated Burst Error Detecting Linear Codes
This paper presents lower bounds on the number of parity-check digits required for a linear code that is capable of detecting errors which are ‘m-repeated burst errors’. Further, codes capable of detecting and simultaneously correcting such errors have also been studied
On 2-Repeated Burst Codes
There are several kinds of burst errors for which error detecting and error correcting codes have been constructed. In this paper, we consider a new kind of burst error which will be termed as ‘2-repeated burst error of length b(fixed)’. Linear codes capable of detecting such errors have been studied. Further, codes capable of detecting and simultaneously correcting such errors have also been dealt with. The paper obtains lower and upper bounds on the number of parity-check digits required for such codes. An example of such a code has also been provided
On Walsh Spectrum of Cryptographic Boolean Function
Walsh transformation of a Boolean function ascertains a number of cryptographic properties of the Boolean function viz, non-linearity, bentness, regularity, correlation immunity and many more. The functions, for which the numerical value of Walsh spectrum is fixed, constitute a class of Boolean functions known as bent functions. Bent functions possess maximum possible non-linearity and therefore have a significant role in design of cryptographic systems. A number of generalisations of bent function in different domains have been proposed in the literature. General expression for Walsh transformation of generalised bent function (GBF) is derived. Using this condition, a set of Diophantine equations whose solvability is a necessary condition for the existence of GBF is also derived. Examples to demonstrate how these equations can be utilised to establish non-existence and regularity of GBFs is presented
Squeezing in Multivariate Spin Systems
In contrast to the canonically conjugate variates , representing the
position and momentum of a particle in the phase space distributions, the three
Cartesian components, ,, of a spin- system constitute
the mutually non-commuting variates in the quasi-probabilistic spin
distributions. It can be shown that a univariate spin distribution is never
squeezed and one needs to look into either bivariate or trivariate
distributions for signatures of squeezing. Several such distributions result if
one considers different characteristic functions or moments based on various
correspondence rules. As an example, discrete probability distribution for an
arbitrary spin-1 assembly is constructed using Wigner-Weyl and Margenau-Hill
correspondence rules. It is also shown that a trivariate spin-1 assembly
resulting from the exposure of nucleus with non-zero quadrupole moment to
combined electric quadrupole field and dipole magnetic field exhibits squeezing
in cerain cases.Comment: 13 pages, 1 Table, Presented at ICSSUR-05, Franc
ON RECOGNITION OF CIPHER BIT STREAM FROM DIFFERENT SOURCES USING MAJORITY VOTING FUSION RULE
In the present paper, majority-voting rule has been investigated for its possible application in cryptological sciences. A novel approach is proposed to address the complex identification problem of overlapping classes. The method for representing patterns using different measurements has been discussed and the majority voting rule is used to fuse the results obtained in different measurement spaces. The proposed approach is quite natural and simple to implement in comparison with usual fusion strategies. Thescheme has been implemented for three-class problem and results were tabulated and presented graphically
Effects of Possible Transitions in Neutral Meson Decays}
We explore the possibility that the existing data on like-sign dileptons at
the resonance consist of events arising from mixing and also from transitions. The
consequences of these nonstandard transitions for certain time-asymmetries
which are likely to be measured at the factories are studied.Comment: {\LARGE \bf 10 pages, no figures, process using latex, TIFR/TH/93-5
Transverse beam polarization and CP-violating triple-gauge-boson couplings in e+e- -> gamma Z
We show that an anomalous CP-violating gamma-gamma-Z vertex gives rise to a
novel asymmetry with transversely polarized electron and positron beams in the
process e+e- -> gamma Z. This asymmetry, which is odd under naive time
reversal, is proportional to the real part of the gamma-gamma-Z CP-violating
coupling. This is in contrast to the simple forward-backward asymmetry of the
gamma (or Z) with unpolarized or longitudinally polarized beams studied
earlier, which is even under naive time reversal, and is proportional to the
imaginary part. We estimate the sensitivity of future experiments to the
determination of CP-odd gamma-gamma-Z and gamma-Z-Z couplings using these
asymmetries and transversely polarized beams.Comment: 13 pages, latex, 7 figures included as postscrip
Probing scalar particle and unparticle couplings in e+ e- -> t tbar with transversely polarized beams
In searching for indications of new physics scalar particle and unparticle
couplings in e^+ e^- \to t\bar t, we consider the role of transversely
polarized initial beams at e^+ e^- colliders. By using a general relativistic
spin density matrix formalism for describing the particles spin states, we find
analytical expressions for the squared amplitude of the process with t or \bar
t polarization measured, including the anomalous coupling contributions. Thanks
to the transversely polarized initial beams these contributions are first order
anomalous coupling corrections to the Standard Model (SM) contributions. We
present and analyse the main features of the SM and anomalous coupling
contributions. We show how differences between SM and anomalous coupling
contributions provide means to search for anomalous coupling manifestations at
future e^+ e^- linear colliders.Comment: 28 pages in LaTeX, including 7 encapsulated PostScript figures,
published versio
On the spectrum of closed k=2 flux tubes in D=2+1 SU(N) gauge theories
We calculate the energy spectrum of a k=2 flux tube that is closed around a
spatial torus, as a function of its length l. We do so for SU(4) and SU(5)
gauge theories in 2 space dimensions. We find that to a very good approximation
the eigenstates belong to the irreducible representations of the SU(N) group
rather than just to its center, Z_N. We obtain convincing evidence that the
low-lying states are, for l not too small, very close to those of the
Nambu-Goto free string theory (in flat space-time). The correction terms appear
to be typically of O(1) in appropriate units, much as one would expect if the
bosonic string model were an effective string theory for the dynamics of these
flux tubes. This is in marked contrast to the case of fundamental flux tubes
where such corrections have been found to be unnaturally small. Moreover we
find that these corrections appear to be particularly small when the `phonons'
along the string have the same momentum, and large when their momentum is
opposite. This provides information about the detailed nature of the
interactions in the effective string theory. We have searched for, but not
found, extra states that would arise from the excitation of the massive modes
presumably associated with the non-trivial structure of the flux tube.Comment: 37 pages, 16 figures, minor changes to text and figure
- …