Kernel Function Definition Completion for Time–Domain State–Space Representations of Radiation Forces: Application to the Hankel Singular Value Decomposition

This paper focuses on the formulation of state–space representations of radiation forces for marine structures using Hankel Singular Value Decomposition (HSVD), a method used to obtain a state–space realization from a Hankel matrix, with the classical definition of the kernel function and its new definition given in this paper. The first part shows the influence of a term commonly neglected and the resulting improvement by taking this term into account. The second part will focus on the feedthrough matrix to understand why some models have none and why some others, such as HSVD, have one. An exact definition of the kernel function will be given underlying its discontinuity and its causality. This study also shows the interest of extrapolating hydrodynamic coefficients before approaching radiation forces by a state–space model.

Serial encryption using the functions of real variable

Context. Using the functions of a real variable in cryptosystems as keys allow increasing their cryptographic strength since it is more difficult to select such keys. Therefore, the development of such systems is relevant. Objective. Cryptosystems with symmetric keys are proposed for encrypting and decrypting a sequence of characters represented as a one-dimensional numerical array of ASCII codes. These keys are functions of a real variable that satisfies certain restrictions. They can be both continuous and discrete. Method. Two cryptosystem options are proposed. In the first embodiment, the transmitting and receiving sides select two functions, the first transmitted symbol, the area of the function definition, and the step of changing the function argument. Discrete messages are encrypted by calculating the first-order integral disproportion of the encrypted array using a function. The corresponding value of the second function is added to the obtained cipher of each symbol for scrambling to complicate the analysis of the intercepted message. On the receiving side, the second function is subtracted and decryption performed by the inverse transformation of the formula for integral disproportion. In the second version, sequential encryption is performed when the cipher obtained using one of the key functions in the first stage is encrypted again by calculating the disproportion using the second function, the key. Accordingly, in two stages, decryption is performed. Results. Examples of encryption and decryption of a sequence of text characters are presented. It is shown that the same character is encoded differently depending on its position in the message. In the given examples it is presented the difficulty of key functions parameters choosing and the cryptographic strength of the proposed cryptosystem. Conclusions. Variants of the cryptosystem using the first-order integral disproportion function are proposed, in which the functions of a real variable serve as keys. To “crack” such a system, it is necessary not only to select the form of each function but also to find the values of its parameters with high accuracy. The system has high cryptographic strength.

Power Series.Orthogonal Operational Expansions

Formulation of the classic Taylor series as an orthogonal concept based on identifying the expansions coefficients as differential transformation applied to a unique function; definition of operational orthogonality by analogy with the Hilbert space and identification of the nth derivative at a point based on the improper integral on the positive semiaxis ; deduction of inversion integrals for Laplace transforms for analytical functions

Power Series.Orthogonal Operational Expansions

Formulation of the classic Taylor series as an orthogonal concept based on identifying the expansions coefficients as differential transformation applied to a unique function; definition of operational orthogonality by analogy with the Hilbert space and identification of the nth derivative at a point based on the improper integral on the positive semiaxis ; deduction of inversion integrals for Laplacen transforms for analytical functions.

Reorienting business education through the lens of Ernest Boyer

PurposeThis article assesses the ability of Boyer's (1990) four-function definition of scholarship to address critiques of business schools. Boyer's definition of scholarship is presented as the foundation for a paradigmatic shift in higher education in business.Design/methodology/approachThe authors developed this conceptual paper by considering information from three sources: 1) Ernest Boyer's Scholarship Reconsidered: Priorities of the Professoriate, 2) articles by four well-known pundits of business education as well as critiques appearing in the Academy of Management Learning and Education Journal and 3) articles in which Boyer's work was the focal point of the article found by searching Google Scholar, two well-known education journals, a prominent database of education articles and the International Handbook of Higher Education (Forest and Altbach, 2007).FindingsA four-function framework based on Boyer's definition of scholarship is proposed to help improve the operations of business schools. The authors also forward ideological and practical implications related to each of Boyer's four functions.Originality/valueFor several decades now, a number of highly respected business scholars have criticized American business education in its current form. These criticisms, although plentiful, have not fueled the magnitude of change needed to have a significant, sustainable impact on business education. The authors suggest that this lack of change is due, in part, to institutional practices and to the absence of a unified framework for how higher education in business should be executed. The authors argue that Boyer's four-function definition of scholarship could provide such a framework.

Modelowanie układów sterowania z użyciem pochodnych ułamkowych

In the paper is presented review of some approaches corelated with subject of using fractional derivatives in control system theory. Popular algorithms used in the industry are presented, along with relating designing methodology. Using of fractional derivatives calculations is relatively new concept, but constantly getting increasing interest. Deliberation in recent years indicate that many scientific problems like thermodynamic or biology problems can be well considered and modeled by fractional order derivatives. On the market there is available tools that support a processes of identification and regulators designing, based on experimental data. One of such tools are toolbox CRONE for MATLAB, which contains three modules: mathematical, identifying, system control designing. That toolbox allows implementation of CRONE regulators with different level of complexity. Other tool is FOMCON, which also is a toolbox for MATLAB and it is based on already existed toolbox FOTF. FOMCON allows to identifying of control system and PIλDµ regulator designing. This article is aiming to present current state of art, discussion about existing tools and concepts correlated with fractional order derivatives and their usage in control system theory, like: gamma function, definition of fractional derivative, Laplace transform and basics of control system theory.

Primitive recursion in the abstract

Recurrence can be used as a function definition schema for any nontrivial free algebra, yielding the same computational complexity in all cases. We show that primitive-recursive computing is in fact independent of free algebras altogether, and can be characterized by a generic programming principle, namely the control of iteration by the depletion of finite components of the underlying structure.