The explosive rise of wireless services necessitates a network connection with high bandwidth, high performance, low mistakes, and adequate channel capacity. Individual mobile users, as well as residential and business clusters are increasingly using the internet and multimedia services, resulting in massive increases in the internet traffic demand. Over the past decade, internet traffic has grown significantly faster than Moore’s law predicted. The current system is facing significant radio frequency spectrum congestion and is unable to successfully transmit growing amounts of (available) data to end users while keeping acceptable delay values in mind. Free space optics is a viable alternative to the current radio frequency technology. This technology has a few advantages, including fast data speeds, unrestricted bandwidth, and excellent security. Since free space optics is invisible to traffic type and data protocol, it may be quickly reliably and profitably integrated into an existing access network. Despite the undeniable benefits of free space optics technology under excellent channel conditions and its wide range of applications, its broad use is hampered by its low link dependability, especially over long distances, caused by atmospheric turbulence-induced decay and weather sensitivity. The best plausible solution is to establish a secondary channel link in the GHz frequency range that works in tandem with the primary free space optics link. A hybrid system that combines free space optics and millimeter wave technologies in this research is presented. The combined system offers a definitive backhaul maintenance, by drastically improving the link range and service availability.

Contemporary approaches to Poland’s Western and Northern Territories revolve around the concept of “postmigration communities”, or more broadly —“postmigration”, understood as a significant feature (or set of features) of community and social phenomena. These terms are present not only in academic discourse, but also in discussions on local identity. They are also an essential element of their symbolic status. Based on field research in the Głowczyce commune in Pomerania, the author tackles the issue of inhabitants’ attitudes towards breaking the historical and cultural continuity and the formation of the community from scratch, as well as the role of postmigration in shaping the symbolic status of the place. The article shows the capacity of the term “postmigration”. In residents’ statements, postmigration appears unnamed, as a problem, a challenge, and an asset. Attitudes towards postmigration reveal diverse attempts to cope with the break in historical and cultural continuity, which turns out to still be a significant element of identity processes taking place in the community in question.

The article presents state of work in technology of free-space optical communications (Free Space Optics − FSO). Both commercially available optical data links and their further development are described. The main elements and operation limiting factors of FSO systems have been identified. Additionally, analyses of FSO/RF hybrid systems application are included. The main aspects of LasBITer project related to such hybrid technology for security and defence applications are presented.

The paper presents verification of a peak detection method cooperating with infrared radiation detector module applications. The work has been divided into parts including SPICE simulations and presentation of results obtained with the constructed prototype. The design of the peak detector dedicated to applications with very short pulses requires a different approach than that for standard solutions. It is mainly caused due to the ratio of pulse width and time period. In the described application this ratio is less than 10%. The paper shows testing of an analogue circuit which is capable to be inserted in these applications.

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

AbstractThe Caputo-Fabrizio definition of the fractional derivative is applied to minimum energy control of fractional positive continuous- time linear systems with bounded inputs. Conditions for the reachability of standard and positive fractional linear continuous-time systems are established. The minimum energy control problem for the fractional positive linear systems with bounded inputs is formulated and solved.

AbstractThe paper presents the problem of estimating in-situ compressive strength of concrete in a comprehensive way, taking into account the possibility of direct tests of cored specimens and indirect methods of non-destructive tests: rebound hammer tests and ultrasonic pulse velocity measurements. The paper approaches the discussed problem in an original, scientifically documented and exhaustive way, in particular in terms of application.

AbstractThe classical Cayley-Hamilton theorem is extended to Drazin inverse matrices and to standard inverse matrices. It is shown that knowing the characteristic polynomial of the singular matrix or nonsingular matrix, it is possible to write the analog Cayley-Hamilton equations for Drazin inverse matrix and for standard inverse matrices.

AbstractThis paper describes a new method of determining the reactive power factor. The reactive power factor herein is calculated on the basis of time samples and not] with the Fourier transform of signals, like it was done previously. The new reactive power factor calculation results from the receiver admittance-operator decomposition into the product of self-adjoint and unitary operators. This is an alternative decomposition to another one, namely into a sum of the Hermitian and skew-Hemiitian operators.

AbstractThis paper is aimed at reviewing the ring of retarded quasipolynomial meromorphic functions (R

AbstractThe stability of fractional standard and positive continuous-time linear systems with state matrices in integer and rational powers is addressed. It is shown that the fractional systems are asymptotically stable if and only if the eigenvalues of the state matrices satisfy some conditions imposed on the phases of the eigenvalues. The fractional standard systems are unstable if the state matrices have at least one positive eigenvalue.

AbstractThis paper describes how to calculate the number of algebraic operations necessary to implement block matrix inversion that occurs, among others, in mathematical models of modern positioning systems of mass storage devices. The inversion method of block matrices is presented as well. The presented form of general formulas describing the calculation complexity of inverted form of block matrix were prepared for three different cases of division into internal blocks. The obtained results are compared with a standard Gaussian method and the “inv” method used in Matlab. The proposed method for matrix inversion is much more effective in comparison in standard Matlab matrix inversion “inv” function (almost two times faster) and is much less numerically complex than standard Gauss method.

AbstractPositive descriptor fractional discrete-time linear systems with fractional different orders are addressed in the paper. The decomposition of the regular pencil is used to extend necessary and sufficient conditions for positivity of the descriptor fractional discrete-time linear system with different fractional orders. A method for finding the decentralized controller for the class of positive systems is proposed and its effectiveness is demonstrated on a numerical example.

AbstractThis paper is concerned with the H

The article presents empirical material obtained in sociological surveys conducted in the Wejherowo area in the year 2014. The purpose of the survey was to record the residents’ opinions on the needs and problems relating to selected functioning aspects of the town and its downtown district, the perception and valuation of the area, the town’s revitalization investments, both planned and in progress, and the perception of the changes taking place in selected spheres of the town’s life. The survey reveals that the dwellers of Wejherowo are capable of responding to the problems the town faces in intellectual and personal dimensions, they follow the postulates related to the ideas and concepts of a creative town more or less consciously, and have a preference for the town ensuring access to the broadly construed culture and entertainment. This encapsulates a vision of developing town cultures, with the focal point evidently shifted from the concept of a town as a place accumulating specimens of architecture and a symbolic space to the town construed as a complex of better facilities and solutions which make everyday life more convenient. More frequently than ever before, town identity becomes the function of negotiations between what is local and what is global. The quality of town life and the features of its ‘town-like character’ appear to be the outcome of continuous and subtle dialectics between the residents and the physical form in which they live, i.e. the town.

Social information is used by animals to communicate, but it also affects their habitat selection and preferences.

We all gesture as we talk, albeit mostly unconsciously. The gestures we produce support and supplement what we are saying. In different cultures, however, the very same gestures may carry very different meanings.

Language is used for more than just communication – it is a tool for interpreting the world around us.

Prof. Stanisław Karpiński discusses groundbreaking research into how plants communicate, remember stress, and process information.

Why is it that people can end up interpreting what is being said to them in such different ways? A lot depends on whether they happen to be in a good or bad mood.

The tale of human progress is also a story of advancements in media technologies. But should we necessarily greet the changes now on the horizon with optimism?

The Polish language is slowly disappearing among the Polish community in Ukraine’s Rivne Oblast. This is due to the influence of the clergy and the emigration of the younger generation.