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1
Ocena jakości połączeń głosowych na podstawie pomiarów urządzeniem SwissQual Diversity Benchmarker
Langer M.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
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2018
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nr 6
312--315, CD
PL
W pracy zawarto analizę pomiarów jakości połączeń głosowych w sieciach telefonii komórkowej, wykonanych wewnątrz budynku (pięciokondygnacyjny „Budynek Trzech Wydziałów”, o długości ok. 152m), w różnych warunkach lokalizacyjnych i natężenia ruchu, za pomocą programu NQDI i urządzenia Diversity Benchmarker firmy SwissQual. Budynek znajduje się w zasięgu trzech stacji bazowych. Mierzono parametry należące do QoS oraz badano parametry jakościowe (QoE).
EN
The paper contains the analysis of listening quality in mobile networks measurements, made inside the building („Budynek Trzech Wydziałów”, about 152m long and five stories), in various localization and mobile intensity. The measurements were made with NQDI software and SwissQual Diversity Benchmarker. The building is seen by three eNB-s. QoS parameters were measured and quality parameters (QoE) were assessed.
2
Content available Spectrum of J-frame operators
Giribet J., Langer M., Leben L., Maestripieri A., Peria F. M., Trunk C.
Opuscula Mathematica
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2018
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Vol. 38, no. 5
623--649
EN
A J-frame is a frame F for a Krein space (H, [•,•] ) which is compatible with the indefinite inner product [•,•] in the sense that it induces an indefinite reconstruction formula that resembles those produced by orthonormal bases in H. With every J-frame the so-called J-frame operator is associated, which is a self-adjoint operator in the Krein space H. The J-frame operator plays an essential role in the indefinite reconstruction formula. In this paper we characterize the class of J-frame operators in a Krein space by a 2 x 2 block operator representation. The J-frame bounds of F are then recovered as the suprema and infima of the numerical ranges of some uniformly positive operators which are build from the entries of the 2x2 block representation. Moreover, this 2x2 block representation is utilized to obtain enclosures for the spectrum of J-frame operators, which finally leads to the construction of a square root. This square root allows a complete description of all J-frames associated with a given J-frame operator.
3
Content available Measurements and Statistical Analysis for Assessment of Availability of Mobile Network Services
Kadamus G., Langer M.
Journal of Telecommunications and Information Technology
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2018
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nr 2
48--52
EN
Availability is an essential feature of telecommunication services. It influences the quality of experience (QoE) associated with individual networks and with the services offered. Therefore, it needs to be allowed for at each level of network design, and has to be controlled at the operation stage. This is achieved by means of various mathematical and numerical tools. In this project listening quality and speech level, which are quality-related features of mobile network services, are measured and analyzed with the Monte Carlo simulation method. Measurements are taken with assistance of the Diversity Benchmarker, a reliable device designed for mobile network testing. Finally, results obtained are compared to assess the applicability of the Monte Carlo method.
4
Content available Possibilities to Optimize QoS with Next SON Versions
Langer M.
Journal of Telecommunications and Information Technology
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2015
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nr 1
27--31
EN
The paper discusses quality of service in LTE and LTE-A networks seen as a challenge that can be met with Self-Organizing Networks (SON) functionalities. The SON concepts have been included in the LTE (E-UTRAN) standards since the first release of the LTE technology. Self-optimization functionalities will monitor and analyze performance measurements, notifications, and self-test results and will automatically trigger re-configuration actions on the affected network nodes when necessary. The SON specifications have been built over the existing 3GPP network management architecture, the ultimate implementation of SON in 4G networks will bring many advantages. Successive SON procedures are waiting for their time and money to be implemented in 4G, though some essential issues for example of inter Radio Access Technology (RAT) interfaces must be overworked.
5
Content available Quality management in 4G wireless networking technology allows to attend high-quality users
Langer M.
Journal of Telecommunications and Information Technology
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2013
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nr 3
48--55
EN
The 4G networks are all-IP based heterogeneous networks that allow users to use any system at anytime and anywhere, and support a variety of personalized, multimedia applications such as multimedia conferencing, video phones, video/movie-on-demand, education-on-demand, streaming media, multimedia messaging, etc. Personalized services should be supported by personal mobility capability, which concentrates on the movement of users instead of users’ terminals. As the technology matures, traffic congestion increases, and competitive pressures mount, QoS and policy management will become more and more important. Also the users come with a number of new requirements on connectivity, and D2D networking technology must follow the idea of “Internet of things”. Operators must make sure they are working with vendors that have a strong framework to supply end-to-end QoS and are capable of supporting evolving needs. The paper discusses qualitative and quantitative indicators of telecommunication services. Main challenges that need to be addressed by nowadays and future systems are shown, and within them the massive growth in traffic volume and in the number of connected devices seems to play the most key role.
6
Content available Monte Carlo method used for a prognosis of selected technological parameters
Langer M.
Journal of Telecommunications and Information Technology
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2007
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nr 3
96-100
EN
In this paper a smart modeling approach for realistic simulation of selected technological parameters is presented. The technology of making contacts with plasma vapor deposition (PVD) method has been chosen for this purpose. The analysis is based on the Monte Carlo (MC) method and uses the Excel worksheet - the simplest tool, easily accessible to anyone. The statistic parameters are calculated and discussed as we introduce this experiment to demonstrate the advantages of design for six sigma (DFSS)
7
Współczynnik przejmowania ciepła w mikrostrukturach chłodzących
Langer M., Lisik Z., Raj E.
Elektronika : prace naukowe
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2005
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nr 10
35-48
PL
Artykuł poświęcony jest metodom obliczania współczynnika przejmowania ciepła, czyli podstawowego parametru wykorzystywanego do oceny efektywności systemów chłodzących układów elektronicznych. Zawiera przegląd podejść standardowych prezentowanych w literaturze oraz implementowanych w komercyjnych programach symulacyjnych dotyczących zagadnień przepływu ciepła i masy (np.: ANSYS), jak również wprowadza nową metodę obliczania współczynnika alfa opracowaną przez autorów. Praca zawiera porównanie wyników otrzymanych przy pomocy wszystkich przedstawionych podejść mikro- i makroskali.
EN
The paper presents detailed analysis of methods of heat transfer coefficient calculations. The authors compare the difference in definition and application in case of two distinct standard approaches that are widely used in nowadays science, and a new micro- approach. The numerical results obtained with the aid of these methods are introduced and compared. In consequence, there is drawn a conclusion that existing standard methods are not suitable for analysis of heat transfer in microchannels. They give only a global picture of the whole process and they do not have a local character. On the other hand, the new micro-approach appears not to have these drawbacks. The authors explain, why new method for estimation of micro alpha coefficient is so good for analysis of water-cooling in flat channels of small dimensions. The theoretical discussion is supported by simulations and calculations that were led with the aid of ANSYS software.
8
Sprzężenie elektrotermiczne w statycznym modelowaniu półprzewodnikowych przyrządów komórkowych
Woźny J., Rinaldi N., Lisik Z., Langer M.
Elektronika : prace naukowe
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2005
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nr 10
49-61
PL
W pracy opisany jest sposób tworzenia modelu elektrotermicznego przyrządu komórkowego mocy. Prezentowany model jest modelem statycznym. Parametry termiczne określane są na podstawie rozwiązania analitycznego równania przewodnictwa cieplnego, w tym wypadku dla struktury prostopadłościennej z powierzchniowym źródłem ciepła. Wykorzystany został model tranzystora bipolarnego oparty na danych pomiarowych. Algorytm został zaimplementowany w programie MATLAB6.5, który udostępnia gotowe funkcje wyznaczania rozwiązania równań uwikłanych. W pracy skupiono się na pokazaniu potrzeby uwzględniania sprzężenia elektrotermicznego w modelowaniu.
EN
The paper describes a realization of the electrothermal coupling in the cellular power devices. A steady state case is investigated. The presented analysis concerns a silicon parallelepiped with a Surface Heat Source which is a model for active areas the bipolar cellular power device. The thermal model is based on matrix of thermal resistances obtained by evaluating the analytical solution of the heat diffusion differential equation. This equation incorporates physical properties of the system like: dimensions, material properties, boundary conditions. The thermal model is entirely defined by the thermal matrix. Any temperature sensitive model can be used as the electrical model of the transistor. In this work a bipolar transistor model has been utilized. The model was established at the University of Naples "Federico II" on the bases of measurements and was described in [2]. The electrothemal coupling was taken into account in the "while" loop where the thermal and electrical model were called one after another until the convergence criterion was met with. Presented results show that the electrothemal coupling should be considered when cellular devices are studied.
9
Mikrostruktury chłodzące
Raj E., Lisik Z., Langer M., Rudzki J.
Elektronika : konstrukcje, technologie, zastosowania
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2004
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Vol. 45, nr 10
19-20
PL
W artykule przedstawiono koncepcję mikrostruktury chłodzącej przeznaczonej do efektywnego odprowadzania ciepła z modułów mocy. Wyniki pomiarów jednej z trzech struktur prototypowych potwierdziły dużą wydajność zaproponowanego rozwiązania.
EN
The paper present a concept of the compact heat sink for integration with power modules. It introduces the three manufactured prototypes and shows the result of the experimental verification of one ofthem. The conducted measurements confirmed huge cooling abilities of examined structures.
10
Model pewnych zjawisk zachodzących podczas syntezy warstw węglowych - możliwość wpływu na jakość uzyskiwanych warstw
Langer M.
Elektronika : prace naukowe
|
1998
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nr 3
243-254
PL
Przedmiotem rozważań niniejszej pracy jest niskociśnieniowa synteza warstw węglowych typu DLC z plazmy węglowodorowej, wzbudzonej w polu elektrycznym wysokiej częstotliwości. Zbadano niektóre właściwości warstw DLC w funkcji położenia na elektrodzie wysokiej częstotliwości. Stwierdzono występowanie istotnych zmian tych warstw. Dla większości zastosowań, szczególnie w elektronice lub optoelektronice, niezbędne jest, by nanoszone warstwy były jednorodne. Zastosowano metodę elementów skończonych dla pokazania zmiany kształtu pola elektrycznego i stwierdzono korelację zmian własności warstw DLC ze zmianami kształtu tego pola. Podjęto już próby aplikacji uzyskiwanych warstw a zastosowanie komory i elektrody w.cz. o odpowiedniej geometrii, zgodnie z wynikami modelu, znacznie poprawiło ich jednorodność.
EN
The method of low pressure synthesis of carbon films with diamond-like carbon (DLC) structure, that are obtained from hydrocarbon radio frequency plasma has been studied here. Some properties of the films have been examined especially as the function of the placing the sample on the rf electrode. The essential changes in the range of these properties have been found. For electronic or optic applications, as well as for many others, it is extremely important to obtain the homogeneity of the whole film. The finite elements method has been applied to show the changes of the electric field shape. The correlation has been found between the changes of the DLC films' properties and the ones of the field shape. Some applications of the films have been implemented already. The obtained results have shown that the chamber and the rf electrode with a special geometry improved this homogeneity of the deposited layers significantly.
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