The methods of abstraction and idealization are commonly viewed as basic to both the natural and the social sciences. Since the 1970s, they have also been a focus of attention in the philosophy and methodology of science. However, their nature as methods, i.e., sequences of instructions, has not been adequately explicated. The paper attempts to capture the core of these methods in the sense of simplified sequences of instructions. The proposal is illustrated in a reconstruction of the application of both methods in economics as a representative of the social sciences., Metody abstrakce a idealizace jsou běžně považovány za základní pro přírodní i společenské vědy. Od sedmdesátých let se pozornost věnuje také filozofii a metodologii vědy. Jejich povaha jako metody, tj. Sekvence instrukcí, nebyla dostatečně vysvětlena. Příspěvek se pokouší zachytit jádro těchto metod ve smyslu zjednodušených sekvencí instrukcí. Návrh je ilustrován rekonstrukcí aplikace obou metod v ekonomii jako zástupce společenských věd., and Juraj Halas
The cyber sphere forms a fifth domain of activities were interactions between state and non-state actors could happen. It starts to play an important role within the conflicts and hostilities. Especially in these situations, international society does not have a unified view on the question how to deal with the activities in cyberspace. We could see the different forms of abuse of cyberspace also within the crisis in Ukraine. This crisis is a good example of the complexity of the legal approach and the (non)capability of the legal understanding of cyber operations and attacks. The goal of this article is to highlight this complexity and to determine the status of cyber incidents realized in the Ukraine from the perspective of international law., Jozef Valuch, Ondrej Hamuľák., and Obsahuje bibliografické odkazy
Knowledge of the forces affecting mostly the description of the artificial satellites motion is very important task at present. This is valid especially for the forces of the non-gravitational origin. Their description is done at best via the in-situ measurements of their dynamlcs manifestations, i.e., to use the high-sensitive microaccelerometers. We already built and proved one such a device consisting of a cubic proof-mass free-flowing within an external cubic cavity. Our accelerometer has been succesfully tested on the RESOURCE F-1 satellite on June 1992. A project
of another experiment is now being prepared under the náme of
”CESAR” with a participation of five central-European countries. The launch of the proposed satellite is envisaged for 1997.
When the nodes or links of communication networks are destroyed,
its effectiveness decreases. Thus, we must design the communication network as stable as possible, not only with respect to the initial disruption, but also with respect to the possible reconstruction of the network. A graph is considered as a modeling network, many graph theoretic parameters have been ušed to describe the stability of communication networks, including connectivity, integrity, tenacity. Several of these deal with two fundamental questions about the resulting graph. How many vertices can still communicate? How difficult is it to reconnect the graph? Stability numbers of a graph measure its durability respect to break down. The neighbour-integrity of a graph is a measure of graph vulnerability. In the neighbour-integrity, it is considered that any failure vertex effects its neighbour vertices. In this work, we define the accessible sets and accessibility number and we consider the neighbour-integrity of Generalised Petersen graphs and the relation with its accessibility number.
We describe multicolor photometric solutions of the long-period Algol RX Geminorum, accretion disk kinematics deduced from
phase-dependent radial velocity observations of disk Hα emission and fits to Hα profiles using a non-LTE disk model.
The softer a potential is, the closer the corresponding Keplerian rotation is to a rigid rotation law. Because of the small radial coupling in such a situation the radial mass flow due to viscosity in an α-accretion disk is very inefficient. Here a model is presented in which the mass of an accretion disk in a soft potential well changes this potential in a sense that an efficient mass flow in radial direction becomes possible, thus making the formation of a centra! mass condensation possib!e. This mechanism is of interest in the context of galactic central regions since it is capable of explaining the existence of centra! masses such as observed in the cores of norma! galaxies; it might aiso be of relevance for the explanation of the activity in AGNs.