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Warsaw, Poland

Prandecki K.,Vistula University | Nawrot K.A.,Poznan University of Economics | Fronia M.,Polish Academy of Sciences | Wawrzynski M.,Young Scientists Team
Problemy Ekorozwoju | Year: 2013

The last decades of the twentieth century and the beginning of the third millennium saw the significant acceleration of globalization processes, which has fundamentally changed and is still changing the world order and the face of the Earth. The qualitative changes that affect the nature of today's global economy require measures necessary for the adjustment to the reality and the specific nature of international relations. This is of particular importance for the principle of sustainable development, which depends on the on-going civilizational change largely shaped by the social expectations. Therefore, the analysis of megatrends in the future civilizational changes becomes essential in the context of the achievement of sustainable development, which is discussed in this article. The discussion focuses on the processes of urbanization, the development of air transport, public networking, institutional changes, and the environment, which have been identified as the key elements of civilizational change in the 2050 horizon, determining sustainable development in its economic, social, and environmental dimension. Source


Zaitsev D.,Vistula University
Information Sciences | Year: 2016

When using Petri nets to investigate deadlock control, structural analysis techniques are applied, which are based on solving systems of linear algebraic equations. To gain an extra computational speed-up when solving sparse linear systems, we examine a sequential clan-composition process, represented by a weighted graph. The system decomposition into clans is represented by a weighted graph. The comparative analysis of sequential composition for subgraphs and edges (pairwise) is presented. The task of constructing a sequence of systems of lower dimension is called an optimal collapse of a weighted graph; the question whether it is NP-complete remains open. Upper and lower bounds for the collapse width, corresponding to the maximal dimension of systems, are derived. A heuristic greedy algorithm of (quasi) optimal collapse is presented and validated statistically. The technique is applicable for solving sparse systems over arbitrary rings (fields) with sign. © 2016 Elsevier Inc. Source


Kowalewski O.,Warsaw School of Economics | Rybinski K.,Vistula University
Oxford Review of Economic Policy | Year: 2011

This article reviews the state's role in the transition economies of Central and Eastern Europe. Among the countries, Poland is perceived as the leader because it was the first economy to emerge from the decline following the transition, as well the only EU member state to survive the crisis without a recession. This success is often attributed to the high quality of government. However, we show that this popular perception is false and that state malfunctions on numerous fronts may soon impede Polish growth prospects. In Poland, the only bright spot is the quality of the financial supervision, which should serve as a role model for other countries. We attribute the malfunctions to the EU accession period that resulted in an unchecked growth of the government and contributed to the weakening of political and legal institutions. © The Authors 2012. Published by Oxford University Press. Source


Placzek S.,Vistula University
Proceedings of 2014 Science and Information Conference, SAI 2014 | Year: 2014

A Neural network with a feed-forward structure with one input, one hidden and one output layer can be presented as a hierarchical two-level structure with two independent subnetworks on both the first and the second level. This process is known as decomposition of an Artificial Neural Network (ANN) into two sub-networks. Two target functions are defined: the output target function Ψ, which defines an error function for all networks. The local target function Φ which defines the error of the first and second layer sub-network adjustment. For the coordination level, two independent functions are defined: G(V) for feed forward and H(V) for back forward. The coordinator ensures that learning algorithms for both levels, first and second, are concatenated. Solving local tasks provides for the achievement of the minimum of the global target function Ψ (global task). The article defines the obligatory conditions that have to be fulfilled (regarding both the first and the second level tasks), for the algorithm to be convergent and achieve the minimum of the global target function (the output function). A three-argument function allows us to study the general learning characteristics for both the first and the second level. Final results are discussed and the positive and negative parameters of the two stage learning algorithm are presented. Matrix weight coefficients are modified after each presentation of learning vectors X (input) and Z (output). © 2014 The Science and Information (SAI) Organization. Source


Czaja L.,Vistula University | Czaja L.,University of Warsaw
Fundamenta Informaticae | Year: 2014

Petri net structures are used as communication model of network systems where message transfer channels are represented by the nets' edges, communicating agents - by nets' places and actions of communication - by nets' transitions, which here are called transmissions. The role of (structured) tokens play send/receive statements, that arrive at random, which makes the distribution of edges change dynamically. In this sense a net is self-modyfying: although the set of agents-places is fixed, the channels and communicating actions vary in the course of the net activity. Problems of deadlock and fairness is investigated. Source

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