计算机检索指纹重码原因分析

本文从指纹本身的特点和规律出发,对计算机检索指纹产生重码的原因进行了分析。

PERFORMANCE ANALYSIS FOR THE RECEIVER WITH ISI

In this paper we use trellis coded amplitude modulation (TC-AM) as models to analyze the receivers with intersymbol interference (ISI) under BPSK and π/4-QPSK modulations.Using the modified generating function and the weight profile function of the TC-AM,the bit error probability for both cases is evaluated in the sense of maximum likelihood decoding.The numerical result is given.

A Relationship Between the Weight Enumerators and Minimal Codewords

In this paper using the weight enumerators of a linear [n, k]--code, we give a theorem about minimal codewords. In this n context, we show that while 1 E C if Wmin〉 n/2 in the binary [n, k] --code C, then all of the nonzero codewords of C are 2 minimal. Therefore, we obtain a corollary.

SDCMA BLIND DETECTION IN FREQUENCY DOMAIN FOR MC DS-CDMA SYSTEMS

This paper proposes Steepest Decreasing Constant Modulus Algorithm （SDCMA） detection in frequency dornain for MultiCarrier Direct Sequence-Code Division Multiple Access （MC DS-CDMA） systems. The proposed algorithm is used to equalize independent ladings of all subcarriers. At the same time we compare the SDCMA blind detection with subspace-based Minimum Mean-Squared Error （MMSE） detection. The simulation results show that the pertbrmance of SDCMA blind detection is superior to that of subspace-based MMSE detection and the complexity of the former is much lower than that of the latter.

HARQ Scheme for MIMO Systems with Antenna Selection

A new type hybrid automatic repeat request(HARQ) scheme based on orthogonal space-time block code(OSTBC) is proposed and evaluated in multiple-input multiple-output(MIMO) systems.The transmit antennas are selected based on the feedback from the receiver.The modulated symbols are encoded by spacetime block code(STBC) and obtained by space time code blocks which are suitable for the number of selected antennas.The total packet error rate(PER) is given by defining the decoding function and the best value of the maximum number of HARQ retransmissions is discussed.Theory and simulation results illustrate that:this new HARQ scheme with antenna selection method has lower PER and the result is also satisfying.

Several Classes of Two-weight or Three-weight Linear Codes and Their Applications

Recently,linear codes with a few weights have been extensively studied due to their applications in secret sharing schemes,constant composition codes,strongly regular graphs and so on.In this paper,based on the Weil sums,several classes of two-weight or three-weight linear codes are presented by choosing a proper defining set,and their weight enumerators and complete weight enumerators are determined.Furthermore,these codes are proven to be minimal.By puncturing these linear codes,two classes of two-weight projective codes are obtained,and the parameters of the corresponding strongly regular graph are given.This paper generalizes the results of[7].

OPTIMAL BINARY CODES FROM ONE-LEE WEIGHT CODES AND TWO-LEE WEIGHT PROJECTIVE CODES OVER Z_4

This paper investigates the structures and properties of one-Lee weight codes and two-Lee weight projective codes over Z4.The authors first give the Pless identities on the Lee weight of linear codes over Z_4.Then the authors study the necessary conditions for linear codes to have one-Lee weight and two-Lee projective weight respectively,the construction methods of one-Lee weight and two-Lee weight projective codes over Z4 are also given.Finally,the authors recall the weight-preserving Gray map from(Z_4~n,Lee weight)to(F_2^(2n),Hamming weight),and produce a family of binary optimal oneweight linear codes and a family of optimal binary two-weight projective linear codes,which reach the Plotkin bound and the Griesmer bound.

Generalized Steiner Triple Systems with Group Size Ten

Generalized Steiner triple systems, GS(2, 3, n, g) are equivalent to (g+1)-ary maximum constant weight codes (n, 3,3)s. In this paper, it is proved that the necessary conditions for the existence of a GS(2,3, n, 10), namely, n ≡ 0,1 (mod 3) and n ≥ 12, are also sufficient.

A MACWILLIAMS TYPE IDENTITY ON LEE WEIGHT FOR LINEAR CODES OVER F_2+uF_2

In this paper, the MacWilliams type identity for the m-ply Lee weight enumerator for linear codes over F2 ＋uF2 is determined. As an application of this identity, the authors obtain a MacWilliams type identity on Lee weight for linear codes over F2m ＋ uF2m. Furthermore, the authors prove a duality for the m-ply Lee weight distributions by taking advantage of the Krawtchouk polynomials.

Optimal p-Ary Codes from One-Weight and Two-Weight Codes over IF_p+ vIF_p

This paper is devoted to determining the structures and properties of one-Lee weight codes and two-Lee weight projective codes Ck1,k2,k3 over p IF+ v IFp with type p2k1pk2pk3. The authors introduce a distance-preserving Gray map from( IFp + v IFp)nto2np. By the Gray map, the authors construct a family of optimal one-Hamming weight p-ary linear codes from one-Lee weight codes over IFp+ v IFp, which attain the Plotkin bound and the Griesmer bound. The authors also obtain a class of optimal p-ary linear codes from two-Lee weight projective codes over IFp + vIFp, which meet the Griesmer bound.

Macwilliams Identities of Linear Codes over the Ring F_2+ uF_2+ vF_2

The Lee weight enumerators and the complete weight enumerators for the linear codes over ring R = F2 ＋ u F2 ＋ v F2 are defined and Gray map from R^nto F2^3n is constructed. By proving the fact that the Gray images of the self-dual codes over R are the self-dual codes over F2, and based on the Mac Williams identities for the Hamming weight enumerators of linear codes over F2, the Mac Williams identities for Lee weight enumerators of linear codes over R are given. Further, by introducing a special variable t, the Mac Williams identities for the complete weight enumerators of linear codes over R are obtained. Finally, an example which illustrates the correctness and function of the two Mac Williams identities is provided.

A Family of Degenerate Codes for Depolarizing Channels

Quantum degenerate code may improve the hashing bound of quantum capacity. We propose a family of quantum degenerate codes derived from two-colorable graphs. The coherent information of the codes is analyticaJly obtained as a function of the channd noise for the depolarizing channel. We find a new code which has a higher noise threshold than that of the repetition code.

A Quantum Secret Sharing Scheme Using Orbital Angular Momentum onto Multiple Spin States Based on Fibonacci Compression Encoding

Since the use of a quantum channel is very expensive for transmitting large messages, it is vital to develop an effective quantum compression encoding scheme that is easy to implement. Given that, with the single-photon spin-orbit entanglement, we propose a quantum secret sharing scheme using orbital angular momentum onto multiple spin states based on Fibonacci compression encoding. In our proposed scheme, we can represent the frequency of any secret message which is typically collection of bits encodings of text or integers as a bitstring using the base Fibonacci sequence, which is encoded multiple spin states for secret shares transmitted to participants. We demonstrate that Fibonacci compression encoding carries excellent properties that enable us to achieve more robust quantum secret sharing schemes with fewer number of photons.

ON THE RELATIVE GENERALIZED HAMMING WEIGHTS OF A 4-DIMENSIONAL LINEAR CODE AND A SUBCODE WITH DIMENSION ONE

Finite projective geometry method is effectively used to study the relative generalized Hamming weights of 4-dimensional linear codes, which are divided into 9 classes in order to get much more information about the relative generalized Hamming weights, and part of the relative generalized Hamming weights of a 4-dimensional linear code with a 1-dimensional subcode are determined.

The weight distributions of a class of non-primitive cyclic codes with two nonzeros

Recently, a class of non-primitive cyclic codes with two nonzeros have received much attention of researchers and their weight distributions have been obtained for several cases of two key parameters related to the nonzeros. In this paper, by evaluating certain Jacobi sums, we determine the weight distributions of this class of cyclic codes for one more special case.