Let $\mathbb N$ be the set of nonnegative integers and $\mathbb Z$ the ring of integers. Let $\mathcal B$ be the ring of $N \times N$ matrices over $\mathbb Z$ generated by the following two matrices: one obtained from the identity matrix by shifting the ones one position to the right and the other one position down. This ring plays an important role in the study of directly finite rings. Calculation of invertible and idempotent elements of $\mathcal B$ yields that the subrings generated by them coincide. This subring is the sum of the ideal $\mathcal F$ consisting of all matrices in $\mathcal B$ with only a finite number of nonzero entries and the subring of $\mathcal B$ generated by the identity matrix. Regular elements are also described. We characterize all ideals of $\mathcal B$, show that all ideals are finitely generated and that not all ideals of $\mathcal B$ are principal. Some general ring theoretic properties of $\mathcal B$ are also established.
The increasing availability of computing power in the past two decades has been used to develop new techniques for optimizing the solution of estimation problem. Today's computational capacity and the widespread availability of computers have enabled the development of a new generation of intelligent computing techniques, such as the algorithm of our interest. This paper presents a new member of the class of stochastic search algorithms (known as Canonical Genetic Algorithm "CGA") for optimizing the maximum likelihood function ln (L(θ, σa2 )) of the first order moving average MA(1) model. The presented strategy is composed of three main steps: recombination, mutation, and selection. The experimental design is based on simulating the CGA with different values of (θ), and sample size n. The results are compared with those of moment method. Based on MSE value obtained from both methods, one can conclude that CGA can give estimators (\hat \theta) for MA(1) parameter which are good and more reliable than those estimators obtained by moment method.
The Cantor-Bernstein theorem was extended to $\sigma $-complete boolean algebras by Sikorski and Tarski. Chang’s MV-algebras are a nontrivial generalization of boolean algebras: they stand to the infinite-valued calculus of Łukasiewicz as boolean algebras stand to the classical two-valued calculus. In this paper we further generalize the Cantor-Bernstein theorem to $\sigma $-complete MV-algebras, and compare it to a related result proved by Jakubík for certain complete MV-algebras.
We continue in the direction of the ideas from the Zhang's paper \cite{Z} about a relationship between Chu spaces and Formal Concept Analysis. We modify this categorical point of view at a classical concept lattice to a generalized concept lattice (in the sense of Krajči \cite{K1}): We define generalized Chu spaces and show that they together with (a special type of) their morphisms form a category. Moreover we define corresponding modifications of the image / inverse image operator and show their commutativity properties with mapping defining generalized concept lattice as fuzzifications of Zhang's ones.
Using a distributional approach to integration in superspace, we investigate a Cauchy-Pompeiu integral formula in super Dunkl-Clifford analysis and several related results, such as Stokes formula, Morera's theorem and Painlevé theorem for super Dunkl-monogenic functions. These results are nice generalizations of well-known facts in complex analysis., Hongfen Yuan., and Obsahuje bibliografické odkazy
A literature survey revealed that the semi-parasitic evergreen shrub Viscum album subsp. album (Viscaceae) has been recorded on 53 taxa of deciduous trees and shrubs (including five hybrids) in the Czech Republic,. Of the host taxa, 26 are native and 27 alien to the Czech flora. The range of hosts covers 13 families. Salicaceae (11 taxa), Rosaceae (11) and Aceraceae (7) are most represented among families. Of the 22 genera harbouring mistletoe, Populus (7 taxa), Acer (7), Tilia (5) and Fraxinus (4) are most represented. A locality at the castle park in the town of Heřmanův Městec, E Bohemia, is reported in detail. In 1978–1981 and 2001, Viscum album subsp. album was observed on 15 host taxa of trees and shrubs, which represents the second highest diversity of host trees in a single locality in the Czech Republic; the richest one, previously reported by Unar et al. (1985) is the Lednice castle park, S Moravia, with 24 taxa. Four more host taxa were recorded in the studied town of Heřmanův Městec outside the park, giving the total of 19 hosts concentrated within a limited area. The occurrence of mistletoe on Prunus padus is reported for the first time from the Czech Republic.
The article focuses on the relationship between the United States of America and the Kingdom of Thailand before and after World War II. The author first seeks to show how this relationship developed in the 19th and early 20th centuries and what the salient characteristics of it were. The second part of the article describes the American attitude toward Thailand during the war and the importance of wartime events for the future of the Thai-American relationship. Finally, the closing section deals mainly with the postwar developments and the reasons for the emergence of the strategic partnership between Bangkok and Washington. Attention is paid to the motivations and expectations of both sides, as it relates to their cooperation. The aim of the article is mainly to show the changed nature of this bilateral relationship, resulting from World War II and events that followed closely in its wake. It also seeks to point out that the common struggle against communism, although important in later years, was neither the sole nor the prevalent reason for the newly emerging American interest in Thailand in the immediate postwar period.
Security mechanisms for wireless sensor networks (WSN) face a great challenge due to the restriction of their small sizes and limited energy. Hence, many protocols for WSN are not designed with the consideration of security. Chaotic cryptosystems have the advantages of high security and little cost of time and space, so this paper proposes a secure cluster routing protocol based on chaotic encryption as well as a conventional symmetric encryption scheme. First, a principal-subordinate chaotic function called N-Logistic-tent is proposed. Data range is thus enlarged as compared to the basic Logistic map and the security is enhanced. In addition, the computation is easier, which does not take much resource. Then, a secure protocol is designed based on it. Most of communication data are encrypted by chaotic keys except the initialization by the base station. Analysis shows that the security of the protocol is improved with a low cost, and it has a balance between resource and security.
We characterize totally ordered sets within the class of all ordered sets containing at least four-element chains. We use a simple relationship between their isotone transformations and the so called 1-endomorphism which is introduced in the paper. Later we describe 1-, 2-, 3-, 4-homomorphisms of ordered sets in the language of super strong mappings.