Introduction The first part of the paper presents several properties of saddle point matrices with two vector blocks. In these block matrices, the top-left block is a real square matrix , the topright block is the column vector with all entries , the bottom-left block is transposed, and the bottom-right block has the single entry . If is symmetric, the saddle point matrix can be interpreted as ...

In this paper, an effective numerical method is introduced for the treatment of nonlinear two-dimensional Volterra-Fredholm integro-differential equations. Here, we use the so-called two-dimensional block-pulse functions.First, the two-dimensional block-pulse operational matrix of integration and differentiation has been presented. Then, by using this matrices, the nonlinear two-dimensional Vol...

Let $mathbf{c}_0$ be the real vector space of all real sequences which converge to zero. For every $x,yin mathbf{c}_0$, it is said that $y$ is block diagonal majorized by $x$ (written $yprec_b x$) if there exists a block diagonal row stochastic matrix $R$ such that $y=Rx$. In this paper we find the possible structure of linear functions $T:mathbf{c}_0rightarrow mathbf{c}_0$ preserving $prec_b$.

An encryption technique is widely used to keep data confidential. Most of the block symmetric algorithms use substitution functions. Often this functions use so called S-BOX matrix. In this paper author presents one software tool for testing and measuring square s-boxes. Based of information theory functions for testing static and dynamic criteria are presented. These criterions are mathematica...

The reverse order laws for {1,3,4}-generalized inverses of a product of two operators have been studied by Wang et al. [J. Wang, H. Zhang, G. Ji, A generalized reverse order law for the products of two operators, Journal of Shaanxi Normal University, 38 (4) (2010), 13–17]. In this paper using a block-operator matrix technique we study mixed-type reverse-order laws for {1,3,4}-generalized invers...

In this paper, by using a block-operator matrix technique, we study mixed-type reverse order laws for {1,3}-, {1,2,3}and {1,3,4}-generalized inverses over Hilbert spaces. It is shown that ( ) ) { } ( ) ( ) ( )( ) { } 1,3 1,3 1,3 1,3 AB B ABB = and ( ) ) { } ( ) ( ) ( )( ) { } ( ) 1,2, 1,2, 1,2, 1,2, , 3, 4 i i i i AB B ABB i = = when the ranges of , , A B AB are closed. Moreover, a new equivale...

Huber’s M-estimation technique is applied to a block-angular regression problem, which may arise from some applications. A recursive, modified Newton approach to computing the estimates is presented. The structure of the problem is exploited to make the algorithm efficient. It is shown how to efficiently compute a descent search direction by using updating/downdating techniques for matrix facto...

In this paper, we propose a session based bit level symmetric key cryptographic technique and it is termed as Spiral Matrix Based Bit Orientation Technique (SMBBOT). SMBBOT consider the input plain text as binary bit stream. During encryption this stream is chopped into manageable sized blocks with variable lengths. Bits of these blocks are taken from MSB to LSB to fit into a square matrix of s...

The problem of two-block disjoint decomposition of completely specified Boolean functions is considered. Recently a good method in functional decomposition category was proposed. This method is based on using the ternary matrix cover approach. Due to investigation and analysis of this method and to search for an appropriate partition, a computer program was developed. After running the program ...

In this letter, we propose a computationally effient equalization technique that employs block minimum mean squared error (MMSE) depending on LDLH factorization. Parallel interference cancellation (PIC) is executed with preobtained output to provide more reliable symbol detection. In particular, the band structure of the frequency domain channel matrix is exploited to reduce the implementation ...