Advancement in Color Image Processing using Geometric Algebra

This paper describes an advancement in color image processing, using geometric algebra. This is achieved using a compact representation of vectors within $n$ dimensional space. Geometric Algebra (GA) is a preferred framework for signal representation and image representation. In this context the R, G, B color channels are not defined separately but as a single entity. As GA provides a rich set of operations, the signal and image processing operations becomes straightforward and the algorithms intuitive. From the experiments described in this paper, it is also possible to conclude that the convolution operation with the rotor masks within GA belong to a class of linear vector filters and can be applied to image or speech signals. The usefulness of the introduced approach has been demonstrated by analyzing and implementing two different types of edge detection schemes

'Derived' and observed sulphosalt-sulphide phase assemblages compared - a case study from Rajpura-Dariba, India

Log aS2-T diagrams for several sulphosalts (and sulphides) are constructed from published thermochemical data. Additionally, extension of published data on the Cu-S system (Barton, 1973) to the univariant phase equilibria involving fahlore and high-chalcocite in the Cu-Sb-As-S system (Luce et al., 1977) permits construction of approximate As-isopleths for fahlore in log aS2-T space. Phase relationships thus derived are compared with the sulphosalt-sulphide assemblages present in the biphase, polymetallic mineralization at Rajpura-Dariba where geology, genesis and mineral-chemistry are well documented. A gratifying correspondence between the two is observed. Biphase origin of the orebody, inferred from geological data, is confirmed, and rigorous narrow limits of variation of aS2 and T could be set for some assemblages belonging to the second phase of mineralization. The phase diagrams also indicate that the observed pyrargyrite-proustite textural relation and the decomposition fabric of some fahlores, independently, point to an intermittent increase in the activities of S2 and As during the second phase mineralization

A novel group signature scheme without one way hash

The group signatures scheme was introduced by Chaum and van Heijst which allow members of a group to sign messages anonymously on behalf of the whole group. Only a designated Group Manager is able to trace the identify of the group member who issued a valid signature. The group members sign a message with their secret key gsk and produce a signature that cannot be linked to the identities of the signers without the secret key of the manager. The group manager can open the signature to recover the identities of the signers in case of any legal dispute. Group signatures have been widely used in Electronic markets where the sellers are the group members, the buyers are the veriers and the market administrator is the group manager. We aim to propose a group signature scheme that is devoid of any one-way hash function and is based upon the Integer Factorization Problem (IFP). The scheme uses the concept of safe primes to further enhance the security of the scheme. The scheme supports message recovery and hence the overload of sending the message is avoided. The scheme satisfies security properties such as Anonymity (The verier cannot link a signature to the identity of the signer), Traceability (The Group Manager can trace the identity of the signer of any valid signature), Unforgeability (A valid signature cannot be produced without the group secret keys), Exculpability (Neither the GM nor any member can produce a signature on behalf of a group member)

Interacting quantum walk on a two-leg flux ladder: Emergence of re-entrant dynamics

We study the quench dynamics of interacting bosons on a two-leg flux ladder by implementing the continuous-time quantum walk and explore the combined effect of the magnetic field and onsite interaction in the presence of uniform flux. We show that in the regime of weak interaction, the magnetic field substantially slows down the spreading of the particles' wavefunction during the dynamics. However, in the presence of strong interaction, we obtain an interesting re-entrant behaviour in the dynamics where the radial velocity associated to the spreading first increases, then decreases, and increases again as a function of the flux strength. We also find a re-entrant dynamics in the chiral motion of the particles as a function of interaction for fixed flux strengths.Comment: 6 pages, 7Fig

VLSI Design and Implementation for Adaptive Filter using LMS Algorithm

Adaptive filters, as part of digital signal systems, have been widely used, as well as in applications such as adaptive noise cancellation, adaptive beam forming, channel equalization, and system identification. However, its implementation takes a great deal and becomes a very important field in digital system world. When FPGA (Field Programmable Logic Array) grows in area and provides a lot of facilities to the designers, it becomes an important competitor in the signal processing market. In general FIR structure has been used more successfully than IIR structure in adaptive filters. However, when the adaptive FIR filter was made this required appropriate algorithm to update the filter’s coefficients. The algorithm used to update the filter coefficient is the Least Mean Square (LMS) algorithm which is known for its simplification, low computational complexity, and better performance in different running environments. When compared to other algorithms used for implementing adaptive filters the LMS algorithm is seen to perform very well in terms of the number of iterations required for convergence. This phenomenon can be achieved by a sufficient choice of bit length to represent the filter’s coefficients. This paper presents a lowcost and high performance programmable digital finite impulse response (FIR) filter. It follows the adaptive algorithm used for the development of the system. The architecture employs the computation sharing algorithm to reduce the computation complexity