The Experts below are selected from a list of 20442 Experts worldwide ranked by ideXlab platform

Remo Probst - One of the best experts on this subject based on the ideXlab platform.

  • self calibration of divided circles on the basis of a Prime factor algorithm
    Measurement Science and Technology, 2008
    Co-Authors: Remo Probst
    Abstract:

    A new method for the self-calibration of divided circles is presented which is based on a known Prime factor algorithm for the discrete Fourier transform (DFT). The method, called Prime factor division (PFD) calibration, is of interest in angle metrology specially for self-calibrating angle encoders, and generally for a significant shortening of the cross-calibration between two divided circles. It requires that the circular division number N can be expressed as a product N = R × S, whereby the factors R and S are relatively Prime Integer numbers. For the self-calibration of a divided circle, N difference measurements between R angle positions in a regular distribution and one reference angle position determined by S are evaluated by a two-dimensional DFT, yielding the N absolute division errors. The factor R is preferably chosen small, down to a minimum of R = 2, whereas the factor S may be as large as appropriate for the division number N of interest. In the case of a cross-calibration between two divided circles, the PFD method reduces the number of measurements necessary from N2 to (R + 1) × N. Experimental results are demonstrated for the calibrations of an optical polygon with 24 faces (Prime factor product 3 × 8) and a gearwheel with 44 teeth (Prime factor product 4 × 11).

  • self calibration of divided circles on the basis of a Prime factor algorithm
    Measurement Science and Technology, 2008
    Co-Authors: Remo Probst
    Abstract:

    A new method for the self-calibration of divided circles is presented which is based on a known Prime factor algorithm for the discrete Fourier transform (DFT). The method, called Prime factor division (PFD) calibration, is of interest in angle metrology specially for self-calibrating angle encoders, and generally for a significant shortening of the cross-calibration between two divided circles. It requires that the circular division number N can be expressed as a product N = R × S, whereby the factors R and S are relatively Prime Integer numbers. For the self-calibration of a divided circle, N difference measurements between R angle positions in a regular distribution and one reference angle position determined by S are evaluated by a two-dimensional DFT, yielding the N absolute division errors. The factor R is preferably chosen small, down to a minimum of R = 2, whereas the factor S may be as large as appropriate for the division number N of interest. In the case of a cross-calibration between two divided circles, the PFD method reduces the number of measurements necessary from N2 to (R + 1) × N. Experimental results are demonstrated for the calibrations of an optical polygon with 24 faces (Prime factor product 3 × 8) and a gearwheel with 44 teeth (Prime factor product 4 × 11).

Radha Poovendran - One of the best experts on this subject based on the ideXlab platform.

  • the power of Primes security of authentication based on a universal hash function family
    Journal of Mathematical Cryptology, 2010
    Co-Authors: Basel Alomair, Andrew Clark, Radha Poovendran
    Abstract:

    Message authentication codes (MACs) based on universal hash-function families are be- coming increasingly popular due to their fast implementation. In this paper, we investigate a family of universal hash functions that has been appeared repeatedly in the literature and provide a detailed algebraic analysis for the security of authentication codes based on this universal hash family. In particular, the universal hash family under analysis, as appeared in the literature, uses operation in the finite field Zp. No previous work has studied the extension of such universal hash family when computations are performed modulo a non-Prime Integer n. In this work, we provide the first such analysis. We investigate the security of authentication when computations are performed over arbi- trary finite Integer rings Zn and derive an explicit relation between the Prime factorization of n and the bound on the probability of successful forgery. More specifically, we show that the probability of successful forgery against authentication codes based on such a universal hash-function family is bounded by the reciprocal of the smallest Prime factor of the modulus n.

Sanghoon Baek - One of the best experts on this subject based on the ideXlab platform.

  • essential dimension of simple algebras in positive characteristic
    Comptes Rendus Mathematique, 2011
    Co-Authors: Sanghoon Baek
    Abstract:

    Abstract Let p be a Prime Integer. For any Integers 1 ⩽ s ⩽ r , p r , p s denotes the class of central simple algebras of degree p r and exponent dividing p s . For any s r , we find a lower bound for the essential p-dimension of p r , p s . Furthermore, we compute an upper bound for 8 , 2 over a field of characteristic 2. As a result, we show ed 2 ( 4 , 2 ) = ed ( 4 , 2 ) = 3 and 3 ⩽ ed ( 8 , 2 ) ⩽ 10 over a field of characteristic 2.

  • essential dimension of simple algebras in positive characteristic
    arXiv: Rings and Algebras, 2010
    Co-Authors: Sanghoon Baek
    Abstract:

    Let $p$ be a Prime Integer, $1\leq s\leq r$ Integers, $F$ a field of characteristic $p$. Let $\cat{Dec}_{p^r}$ denote the class of the tensor product of $r$ $p$-symbols and $\cat{Alg}_{p^r,p^s}$ denote the class of central simple algebras of degree $p^r$ and exponent dividing $p^s$. For any Integers $s

Ganesh Aithal - One of the best experts on this subject based on the ideXlab platform.

  • generation of maximum length non binary key sequence and its application for stream cipher based on residue number system
    Journal of Computational Science, 2017
    Co-Authors: K B Sudeepa, Ganesh Aithal
    Abstract:

    A cipher system in which the data is sequence of binary digits from data source and secrete key is also a random sequence of binary digits is called Stream cipher system. The stream cipher system which uses only binary information and key to get binary cipher text is known as binary stream cipher system. In this the encryption algorithm is bit by bit XOR operations of plain text bit and corresponding key sequence bit respectively. This concept further generalized to a non binary cipher system defined over any finite field GF (p), where p is Prime Integer. Again generalizing further it can also be defined a stream cipher system over the a ring Zm, arithmetic operations are carried out over modulo m, where m is suitable large composite Integers and the ring is a set which satisfies closure, associative, distributive and commutative properties on addition and multiplication operation. The effectiveness of the non binary stream cipher system is based on different parameters mainly on encryption/decryption algorithm, key generation and its parameters. This paper concentrates on generating non binary key sequence of maximum length. This generated key is used for the application of Residue Number System (RNS) based stream cipher system. The properties like, uniformity, independence and maximum length for the key sequence is tested and verified. Also security issues of cipher systems using these key sequences for an image are tested and evaluated for its strength.

Ali Zafari - One of the best experts on this subject based on the ideXlab platform.

  • Some Algebraic Properties of a Class of Integral Graphs Determined by Their Spectrum
    'Hindawi Limited', 2021
    Co-Authors: Jia-bao Liu, Morteza S. Mirafzal, Ali Zafari
    Abstract:

    Let Γ=V,E be a graph. If all the eigenvalues of the adjacency matrix of the graph Γ are Integers, then we say that Γ is an integral graph. A graph Γ is determined by its spectrum if every graph cospectral to it is in fact isomorphic to it. In this paper, we investigate some algebraic properties of the Cayley graph Γ=Cayℤn,S, where n=pm (p is a Prime Integer and m∈ℕ) and S=a∈ℤn|a,n=1. First, we show that Γ is an integral graph. Also, we determine the automorphism group of Γ. Moreover, we show that Γ and Kv▽Γ are determined by their spectrum