bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability of MIS transistors with plasma deposited Al2O3 gate dielectric film
Authors: Szmidt Jan , Werbowy Aleksander , Dusiński Emil , Zdunek Krzysztof
Published: April 2024

The paper presents the parameters of MIS tran- sistors with plasma deposited thin film aluminum oxide gate insulator. Al2O3 films were synthesized by means of the low- energy, low-temperature reactive pulse plasma (RPP) method. Investigated transistors, with channel width to length (W/L) ratios of 200/10 [ mm/ mm] and 200/20 [ mm/ mm] were manu- factured in a standard microelectronic technological labora- tory. In order to determine the most important parameters of produced devices there were measured their electrical charac- teristics. The distribution of the threshold voltage values was studied on a representative set of over two hundred structures
Comparison of gate leakage current components in metal-insulator-semiconductor structures with high-k gate dielectrics
Authors: Janik Tomasz , Majkusiak Bogdan , Korwin-Pawłowski Michał
Published: April 2024

Numerical simulations of the gate leakage current in metal-insulator-semiconductor (MIS) structures based on the transfer matrix approach were carried out. They show contribution of different components of this current in MIS structures with best known high-k dielectrics such as Ta 2 O 5 and TiO 2 . The comparison of the gate leakage current in MIS structures with SiO 2 layer as well Ta 2 O 5 and TiO 2 layers is presented as well. Additionally, the minimum Si electron affinity to a gate dielectric which allows to preserve given level of the gate leakage current is proposed.
An impact of physical phenomena on admittances of partially-depleted SOI MOSFETs
Authors: Gibki Jan
Published: April 2024

An in uence of the selected physical phenom- ena: impact ionization in silicon and time variation of inter- nal electric field distribution in partially-depleted (PD) SOI MOSFETs on several C-V characteristics of these devices is presented. The role of avalanche multiplication in the so- called
Adsorption properties of porous silicon
Authors: Gotszalk Teodor , Rangelow Ivo W. , Grabiec Piotr
Published: April 2024

Porous silicon shows some interesting features for micromechanical applications. Some applications make use of its high surface-to-volume ratio. A capacitive gas or humidity sensor using the adsorption of gases on the porous surface can be easily fabricated. However an opportunity for more sensitive device is given by micromechanical structure. In this paper we report on the piezoresistive cantilever beam structure with porous silicon adsorbing spot as a gas sensor.
Fabrication and properties of the field emission array with self-alignment gate electrode
Authors: Grabiec Piotr , Studzińska Krystyna , Zaborowski Michał , Mitura Stanisław , Biehl Steffen , Hudek Peter , Kostic Ivan , Jakubowski Andrzej , Rangelow Ivo W.
Published: April 2024

A new method for the fabrication of field emis- sion arrays (FEA) based on bulk/surface silicon micromachin- ing and diamond-like-carbon (DLC) coating was developed. A matrix of self-aligned electron field emitters is formed in sil- icon by mean anisotropic etching in alkali solution of the front silicon film through micro holes opened in silicon oxide layer. The field emission of the fabricated emitter tips is enhanced by a diamond-like-carbon film formed by chemical vapor de- position on the microtips. Back side contacts are formed by metal patterning. Detailed Raman, Auger and TEM investi- gations of the deposited DLC films (nanocrystalline diamond smaller than 10 nm) will be presented. In this paper we dis- cuss the problems related to the development of field emission arrays technology. We also demonstrate examples of devices fabricated according to those technologies.
Challenges in ultrathin oxide layers formation
Authors: Bec Romulad B. , Jakubowsk Andrzej , Łukasiak Lidia , Korwin-Pawłowski Michał
Published: April 2024

In near future silicon technology cannot do without ultrathin oxides, as it becomes clear from the Roadmap 2000. Formation, however, of such layers creates a lot of technical and technological problems. The aim of this paper is to present the technological methods that potentially can be used for formation of ultrathin oxide layers for next generations ICs. The methods are brie y described and their pros and cons are discussed.
High-temperature instability processes in SOI structures and MOSFETs
Authors: Nazarov Alexei N. , Kilchytska V. I. , Vovk Ja. N. , Colinge J. P.
Published: April 2024

The paper reviews the problems related to BOX high-temperature instability in SOI structures and MOSFETs. The methods of bias-temperature research applied to SOI structures and SOI MOSFETs are analysed and the results of combined electrical studies of ZMR, and SIMOX SOI struc- tures are presented. The studies are focused mainly on elec- trical discharging processes in the BOX at high temperature and its link with new instability phenomena such as high- temperature kink effects in SOI MOSFETs.
Reliability of deep submicron MOSFETs
Authors: Balestra Francis
Published: April 2024

In this work, a review of the reliability of n- and p-channel Si and SOI MOSFETs as a function of gate length and temperature is given. The main hot carrier effects and degradations are compared for bulk and SOI devices in a wide range of gate length, down to deep submicron. The worst case aging, device lifetime and maximum drain bias that can be applied are addressed. The physical mechanisms and the emergence of new phenomena at the origin of the degradation are studied for advanced MOS transistors. The impact of the substrate bias is also outlined.
SiGe field effect transistors
Authors: Whall Terrence E. , Parker Evan H. C.
Published: April 2024

Recent and encouraging developments in Schot- tky and MOS gated Si/SiGe field effect transistors are sur- veyed. Circuit applications are now beginning to be investi- gated. The authors discuss some of this work and consider future prospects for the role of SiGe field effect devices in mobile communications.
Preface
Authors: Jakubowski Andrzej , Werbowy Aleksander , Łukasiak Lidia
Published: April 2024

Preface
Methods for description of the total field propagation in the irregular dielectric waveguides
Authors: Bekker Ella V. , Romanova Elena A.
Published: April 2024

Numerical and semi-analytical methods useful for analysis of the total field propagation in dielectric waveguides with sharp and smooth discontinuities are reviewed. The efficiency of these methods to model the field propagation in such structures is discussed comparatively. As an example, spatial transient regime of the radiation field propagation in planar step-index waveguide excited by a Gaussian beam is simulated numerically by two different beam propagation methods.
Analysis of optical-microwave mixing process in electro-optical modulators
Authors: Szczepaniak Zenon R.
Published: April 2024

The principle of operation and the general parameters of the electro-optical Mach-Zehnder modulators are reminded in the paper. With the use of the mathematical relationships describing the transmission of the optical signal through the modulator, the theoretical model of the optical signal transmission with two modulating signals at two frequencies will be presented. The theoretical relationships describing the efficiency of the optical-microwave mixing and frequency multiplying in the two-tone operation will be derived. The analysis and the simulations will be performed for different operating points, where the nonlinearity of the transmission characteristic is specially strong.
IP over optical network: strategy of deployment
Authors: Klinkowski Mirosław , Marciniak Marian
Published: April 2024

In this paper, we present main issues of application IP technology directly over optical transport network. The capabilities of WDM transmission systems and techniques which allow the integration of IP with the physical layer are discussed. A detailed description of most solutions is reported. In particular the MPLS/MP$mathbf{lambda}$S techniques are discussed in detail. Also problems for further development are outlined.
Model of e-book for distance-learning courses
Authors: Galwas Bogdan A. , Pajer Mariusz , Chęć Jolanta
Published: April 2024

Structure of electronic book, prepared as auxiliary materials of courses for specialists in the field of telecommunications and informatics, will be described. Assumptions undertaken and their grounds will be presented. Model of a~single lecture, way of a control of student progress and technique of movement through the course content will be described.
Performance of CDMA systems with Walsh and PN coding
Authors: Dołowski Jerzy
Published: April 2024

Wideband CDMA method has been recently investigated for its using in the future communication systems. Such systems capacity depends on many factors, the main is multi-access interference (MAI). MAI~is an inherent CDMA property connected to correlation characteristics of codes used to access and to spreading. The influence on CDMA performance of these codes families and parameters is presented in this paper. The standard Gaussian approximation has been used for interference analysis. Bit error rate (BER) on detector output is a~measure of interference influence on transmission quality. It can be used for SNRi evaluation on receiver input for channel assignment and handover procedures. The results of interference analysis for the pseudo-noise sequences (M-sequences, Gold, de`Bruin and Jennings) as well as for the Walsh orthogonal mapping are presented in this paper.
Radio wave propagation and single-cell coverage prediction of broadband radio access systems including passive reflectors
Authors: Bauer Georg , Freese Jens
Published: April 2024

This paper presents the scheme of a software planing tool for single microcells of broadband radio access systems operating at millimeter waves, providing local multipoint distribution services (LMDS), particularly in urban or suburban areas. The aim of this planing tool is to provide operators with information, which supports the assessment of the profitability by calculating link budgets and the area coverage and by roughly estimating the maximum number of potential customers, i.e. the total number of households in a~certain area, as well as the number of customers (households) which will actually be covered from a site. A household is here considered as a single apartment or flat, thus a building usually consists of several households. This novel household-estimation model is able to estimate the number of households based only on the 3D-data of buildings, without using residential data. Besides the optimization of line-of-sight (LOS) coverage, also the possibility is considered to enhance the coverage into shadowed areas by using optimized reflectors as passive repeaters up to distances of 1 km from the base station, depending on the system margin and the rain climate zone. All calculations are based on 3D-databases of both, buildings and vegetation.
Intra- and inter-cell interference investigations for broadband radio access systems above 10 GHz
Authors: Bose Ranjan , Hayn Andreas , Jakoby Rolf
Published: April 2024

Local multipoint distribution systems (LMDS) operating above 10 GHz have a large bandwidth (2--3 GHz) but a very limited range. These systems can provide coverage to a few kilometers only. The size of the macro cells illuminated by the base stations, where line of sight (LOS) exists, is 1 to 6 km. To provide coverage to customers where LOS is not possible, repeaters or passive reflectors may be used. In this paper we present first results of reflection measurements at 42 GHz, and based on that, simple multipath studies, taking into account the beamwidth of the antennas of both, transmitter and receiver. Secondly, LOS cochannel and adjacent channel interference are assessed for cellular LMDS networks. As suggested in the CRABS report, the maximal spectral efficiency can be obtained with a dual frequency and polarization reuse plan. This frequency and polarization reuse leads to interference. In this paper we have first calculated the cochannel interference (CCI) and the adjacent channel interference (ACI) due to the frequency/polarization reuse schemes suggested in the CRABS report. The effects of the variation of the half power beam width (HPBW) of the receiver, the time percentage parameter p, and the cell radius on C are also reported. In the latter part of the paper we propose a simple interference reduction technique based on re-orientation of the receiver antennas. We have also explored the possibility of using trellis coded modulation (TCM) for reducing interference levels. Initial results have been found to be quite encouraging.
Challenges before National Institute of Telecommunications after fifty years of its activity
Authors: Wierzbicki Andrzej P.
Published: April 2024

In the year 2001 we celebrate the fifty anniversary of the activity of National Institute of Telecommunications under its present name (in Polish: Instytut Łączności). Although we can date earlier the beginnings of the Institute, we will not present here its detailed history that is discussed in other papers. This paper presents rather the transformation of the Institute in last years, resulting from the systemic transformation of Poland. We describe: new mission of the Institute, the results of structural changes of the Institute in last five years, an outline of long-term research programme. Finally, the paper addresses the challenges before the Institute on the verge of the new milenium.
Photo-devices for optical controlling of microwave circuits
Authors: Szczepaniak Zenon R. , Galwas Bogdan A.
Published: April 2024

The most important optical devices which can be used for controlling microwave circuits will be presented in the paper. The performance and the parameters of the devices such as semiconductor microwave optoelectronic switches, photodiodes and phototransistors were described. The influence of the optical illumination on their microwave parameters will be described in details, including the our own investigations and simulations results. Several applications of such devices and their potential possibilities will be presented.
Optimum double-matched detection and its application to SSMA systems
Authors: Pawelec Jozef Jacek
Published: April 2024

This paper is concerned with the issue of optimum detection of known signal in nonwhite noise and/or narrow-band interference. The detection is carried out in three steps. First, some function related to the power spectrum of interfering process I(z) is estimated via adaptation. Second, the signal interference is whitened due to I(z). Third, the replica of signal is filtered via I(z) to match it to the deformed signal in the previous step. The simulation of SS reception in presence of NB interference shows a high gain in comparison to classical single-matched detection.
Method of analytical regularization based on the static part inversion in wave scattering by imperfect thin screens
Authors: Nosich Alexander I.
Published: April 2024

The paper is focussed on the development of the method of analytical regularization (MAR) in electromagnetic wave scattering and absorption by imperfect scatterers shaped as thin screens.
Precise measurement of complex permittivity of materials for telecommunications devices
Authors: Nakamura Takayuki , Nikawa Yoshio
Published: April 2024

In order to obtain precise complex permittivity of the dielectric materials obtained from the perturbation method a correction curve is made using the electromagnetic field simulator which applies transmission line modeling (TLM) method. In this experiment, generated microwave power with the frequency of 2.45 GHz is applied to heat dielectric material while measuring temperature dependence of complex permittivity of dielectric material. To obtain these objectives cavity resonator with cooling system is designed. It is found from the result that the accurate temperature dependence of complex permittivity of the materials can be obtained by the method presented here.
Stop criteria for retransmission termination in soft-combining algorithms
Authors: Caldera Manora
Published: April 2024

Soft-combining algorithms use retransmissions of the same codeword to improve the reliability of communication over very noisy channels. In this paper, soft-outputs from a maximum a posteriori (MAP) decoder are used as a priori information for decoding of retransmitted codewords. As all received words may not need the same number of retransmissions to achieve satisfactory reliability, a stop criterion to terminate retransmissions needs to be identified. As a first and very simple stop criterion, we propose an algorithm which uses the sign of the soft-output at the MAP decoder. The performance obtained with this stop criterion is compared with the one assuming a genius observer, which identifies otherwise undetectable errors. Since this technique needs always a particular number of initial retransmissions, we exploit cross-entropy between subsequent retransmissions as a more advanced but still simple stop criterion. Simulation results show that significant performance improvement can be gained with soft-combining techniques compared to simple hard or soft decision decoding. It also shows that the examined stop criteria perform very close to the optimistic case of a genius observer.
Error statistics for concatenated systems on non-renewal time-varying channels
Authors: Pimentel Cecilio
Published: April 2024

The statistics of the error process generated by a discrete super channel formed by the concatenation of a constrained encoder, a non-renewal finite state channel (FSC), and a constrained decoder is studied in this paper. First, recursions are developed for the error weight distribution. This statistics is relevant to the design of coding schemes and interleaving in concatenated systems. We also study the renewal nature of the residual error process as modified by the constrained decoder. Ferreira et al. conjectured that if the channel model is a renewal FSC, the super channel can be modeled as a similar renewal model. We use a statistics called the multigap distribution to analytically disprove this hypothesis. Furthermore, the effect of interleaving is investigated from a new perspective using the variance of the multigap distribution.
Simulating capture behaviour in 802.11 radio modems
Authors: Ware Christopher , Chicharo Joe
Published: April 2024

Simulation plays an important role in the performance evaluation of MAC protocols. Building simulation models which are able to accurately model physical behaviour is fundamental to the outcome of such techniques. Through both qualitative and quantitative comparison of experimental trace data against simulation results obtained using delay, power, and hybrid capture models, this paper investigates the performance of various packet capture models in the simulation analysis of the 802.11 PHY and MAC layer protocols. We illustrate these models are unable to accurately describe the fairness properties of the experimental data. A new model is proposed, Message Retraining, to describe the operation of an 802.11 receiver. We illustrate that the Message Retraining reception model is able to model the fairness characteristics obtained with an IEEE 802.11 radio modem more accurately than the previous capture models.
Memory truncation and crosstalk cancellation for efficient Viterbi detection in FDMA systems
Authors: Mertins Alfred
Published: April 2024

In this paper, the design of optimal receive filter banks for frequency division multiple access (FDMA) over frequency selective channels is investigated. A new design strategy based on the principle of memory truncation, rather than equalization, is presented. Through the receive filters, each subchannel is truncated to a pre-defined length, and the final data recovery is carried out via low complexity Viterbi detectors. Both closed form designs and adaptive techniques are discussed. Design examples are presented for high speed transmission over copper wires. The examples show that memory truncation allows significant performance improvements over the often used minimum mean squared error (MMSE) equalization.
Source enhanced linear prediction of speech incorporating simultaneously masked spectral weighting
Authors: Lukasiak Jason , Burnett Ian S.
Published: April 2024

Linear prediction is the cornerstone of most modern speech compression algorithms. This paper proposes modifying the calculation of the linear predictor coefficients to incorporate a~weighting function based on the simultaneous masking property of the ear. The resultant prediction filter better models the perceptual characteristics of the source and results in the removal of more perceptually important information from the input speech signal than a standard LP filter. When employed in a low rate speech codec the net effect is an improvement in subjective quality, with no increase in transmission rate and only a modest increase in computational complexity.
An introduction to envelope constrained filter design
Authors: Cantoni Antonio , Vo Ba-Ngu , Teo Kok Lay
Published: April 2024

Envelope constrained filter design is concerned with the time domain synthesis of a filter whose response to a specified input signal stays within prescribed upper and lower bounds and in addition has minimal noise enhancement. In many practical applications, a ``soft`` approach, such as least mean square, is not the most suitable and it becomes necessary to use ``hard`` constraints such as the ones considered in the paper. We present an overview of key ideas related to robust continuous time envelope constrained filter design.
Distortion and noise problems of subcarrier multiplexed optical systems
Authors: Udvary Eszter , Marozsak Tam´as
Published: April 2024

In this paper investigation of subcarrier multiplexed optical subsystems for optically supported communication systems is presented. Noise and spurious free dynamic range are the main parameters, which are determined by the applied optical transmission. The frequency dependence of these parameters and optimal frequency chosen is presented.
A broadband uniplanar quasi-Yagi antenna - parameter study in application to a spatial power combiner
Authors: Białkowski Marek E. , Song Hyok J. , Kabacik Paweł
Published: April 2024

A parameter study is performed of a broadband uniplanar quasi-Yagi antenna with regard to its design and use in a~spatial power combiner. A 3D full-wave electromagnetic field analysis is applied to identify parameters, which mostly affect the design frequency and operational bandwidth of this antenna. Optimal design conditions are determined. Using these design criteria a passive spatial power combiner employing trays of back-to-back connected quasi-Yagi antennas is developed. This combiner is investigated in terms of insertion losses and field uniformity, which are key factors in obtaining high power combining efficiency.
New type of microstrip antenna with ferroelectric layer
Authors: Models Józef , Yashchyshyn Yevhen
Published: April 2024

new type of microstrip antenna is proposed using a voltage-controlled ferroelectric thin tape in the multilayered structure. This paper presents the ferroelectric thin tape, its theoretical analysis and design. The results indicate that this concept has many advantages, is very practical and promising. It gives possibilities of several applications, e.g. in smart antennas.
Geometrical representation of a monochromatic electromagnetic wave using the tangential vector approach
Authors: Carrea Laura , Wanielik Gerd
Published: April 2024

The aim of this work is to develop a coherent polarimetric model and to find a geometrical description of a monochromatic wave. The spinor form of the electrical field, its links to the coherency matrix and the Poincare` sphere are introduced with the aim to obtain a geometrical representation of the spinor. It consists, from the ``polarization point of view``, on the polarization vector and a tangential plane to the Poincare` sphere where it is possible to visualize the zero phase.
The priority assignment for detected targets in multifunction radar
Authors: Komorniczak Wojciech , Kuczerski Tomasz , Pietrasiński Jerzy F.
Published: April 2024

In a multifunction radar there is necessity to manage its very limited resources. This management should concern, among others, detected targets importance description. So information of those with lower priority will be refreshed more rarely. Presented paper describes system that assigns ranks for all detected objects in real time and then puts targets in order of priority. The system is based on structure of artificial neuron. Methods of neuron learning are discussed.
A dedicated computer system for FM-CW radar applications
Authors: Heijnen Silvester Henri , Van Sinttruijen Jaques S. , Van der Zwan Fred W.
Published: April 2024

In this paper, a DSP based computer system for FM-CW radar applications is described. Besides data acquisition and storage, the computer system will also be used for front-end data processing and system control. Processing includes filtering and clutter suppression. The radar for which the computer is designed is a multi parameter atmospheric profiler capable of doing Doppler and polarimetric measurements. The computer system will allow for a measurement of the full polarimetric scattering matrix over 512 range cells and 512 Doppler cells in 2
Generalized radar/radiometry imaging problems
Authors: Prudyus Ivan , Voloshynovskiy Sviatoslav , Synyavskyy Andriy , Holotyak Taras , Lazko Leonid
Published: April 2024

In the paper the results of spatio-temporal imaging simulation based on radar, synthetic aperture radar (SAR) and radiometry systems are presented. The analytical relationship between object scattering/emitting and the formed image is given and the general approach for the description of imaging system by means of Frendholm equation solution is developed. The potential limit of image resolution based on Rao-Cramer inequality is estimated.
24 GHz radar sensors for automotive applications
Authors: Klotz Michael , Rohling Hermann
Published: April 2024

Automotive radar systems using integrated 24 GHz radar sensor techniques are currently under development [1]. This paper describes a radar network consisting of four sensors distributed behind the front bumper of an experimental car. Each single sensor measures the target range with high accuracy. A multilateration technique is used in the radar network for precise azimuth angle estimation even in multiple-target situations. The system performance is shown in real traffic situations for parking aid, stop
Doppler polarimetric ground clutter identification and suppression for atmospheric radars based on co-polar correlation
Authors: Moisseev Dmitri , Unal Christine , Russchenberg Herman , Ligthart Leo P.
Published: April 2024

A new clutter suppression technique that uses both Doppler and polarimetric information is presented. Polarimetric properties of the target and clutter are calculated per Doppler frequency cell and based on this information clutter suppression is performed. This new clutter suppression technique is demonstrated with radar measurements of precipitation made by the Delft atmospheric research radar (DARR).
Preface
Authors: Modelski Józef
Published: April 2024

Preface
The 100 W class A power amplifier for L-band T/R module
Authors: Wojtasiak Wojciech , Gryglewski Daniel , Sędek Edward
Published: April 2024

In the paper a balanced high power amplifier with class A silicon bipolar transistors for L-band T/R module is described. The amplifier was designed for maximum power and minimum transmitance distortions. The obtained parameters of the amplifier are as follow: output power at 1 dB compression P1 dB > 49 dBm, linear gain |S21| > 10 dB, and transmitance deviations during the RF pulse: phase arg(S21)<0.90 and Pout<0.2 dB.
Optical gain in one-dimensional photonic band gap structures with n-i-p-i crystal layers
Authors: Nefedov Igor S. , Gusyatnikov Victor N. , Marciniak Marian , Kononenko Valerii K. , Ushakov Dmitrii V.
Published: April 2024

The gain enhancement in a layered periodic photonic band gap structure containing active medium based on GaAs n-i-p-i superlattices separated by AlGaAs layers is analyzed. The dependences of extinction coefficient and refractive index on excitation level and wavelength are presented. Transmission characteristics of a probe light versus excitation level are calculated. It is shown that the threshold of generation can be essentially reduced if the wavelength of probe light falls to the band gap edge.
Optical-microwave transmission system with subcarrier multiplexing for industrial measurement systems
Authors: Dawidczyk Jarosław , Galwas Bogdan A. , Skulski Jerzy , Szczepaniak Zenon R. , Gruchała Henryk
Published: April 2024

We describe short-distance three-channel optical-microwave link with subcarrier multiplexing for transmission digital and/or analog data between different points of industrial measurement systems. The optical fiber link operates with Fabry-Perot laser at 1300 nm, multimode fiber and PIN photodiode receiver. From microwave point of view three carriers with frequencies 600 MHz, 800 MHz and 1000 MHz were chosen. The structure and main parameters of a link are reported and discussed.
New multimedia and telematic tools for asynchronous distance learning
Authors: Pajer Mariusz , Chęć Jolanta
Published: April 2024

New tools of modern education, connected mainly with Internet, are described in the paper. Their characteristics, principles of application were discussed in succession. Evaluation trail of their usefulness was done. Possibilities of carrying on laboratory experiments and distance designing were described. Probe to foresee directions of further development of Internet tools in the educational process was done.
Whispering gallery resonator method for measurementspermittivity
Authors: Derzakowski Krzysztof , Abramowic Adam , Krupka Jerzy
Published: April 2024

The new method of measuring permittivity is described. The measurements are performed using whispering gallery mode open dielectric resonators. The accuracy is assured by applications of the mode matching method. Three resonant modes (HE511, HE611 and HE711) are used in measurement procedure. Accuracy of the method is much better than 0.3% for the relative permittivity having values from 20 to 50.
Estimation of internal distribution of temperature inside biological tissues by means of multifrequency microwave thermograph
Authors: Stec Bronisław , Dobrowolski Andrzej
Published: April 2024

The paper presents problems connected with thermal radiation of human bodies in microwave range in aspect of diagnosis breast carcinoma. A~mathematical model of transmission thermal radiation through tissues is introduced and methods of measurement of temperature, depth and size of heat source, by means of multifrequency microwave thermograph [1-7], are described. Theoretical considerations are supplemented with presentation of result experiments.
A method for evaluation of uncertainties of noise parameter measurement
Authors: Schmidt-Szałowski Marek , Wiatr Wojciech
Published: April 2024

The assessment of uncertainties of a two-port noise parameters measurement, presented in the paper, relies on modeling of sources of errors and an investigation of propagation of the errors through a measurement system. This approach is based on a simplified additive error model and small-change sensitivity analysis. The evaluated uncertainties agrees with those observed in experiments. This method may be implemented in automatic noise measurement systems for on-line uncertainty assessment and for optimization of the design of an experiment.
Simple analysis of the impact of packet loss and delay on voice transmission quality
Authors: Perlicki Krzysztof
Published: April 2024

In this paper a simple analytical expression based on E-model is applied to analyse the impact of packet loss and delay on voice transmission quality. The relationship between overall transmission quality rating, packet loss and delay G.711, G.723 and G.729 codecs is presented.
On a method to authenticate and verify digital streams
Authors: Wysocki Beata Joanna , Wang Yejing , Safavi-Naini Reihaneh
Published: April 2024

Recently, digital streams have become widely used to make audio, video, and other media available in real-time over the Internet. As with other transmission methods, the recipient needs to have a possibility to verify the source and authenticity of the received information. Several techniques have been proposed to deal with this issue. Most of them are vulnerable to packet losses or they introduce unacceptable computational and/or communication overheads. Some of the graph-based techniques provide immunity to burst losses of certain length. However, these techniques are not immune to the loss of packets containing signatures or occasional burst of lengths greater than the assumed one. In the paper, we propose a modification to one of the graph-based techniques that introduces immunity to the loss of packets containing signatures, without introducing any additional overheads.
Efficient procedure for capacitance matrix calculation of multilayer VLSI interconnects using quasi-static analysis and Fourier series
Authors: Nauwelaers Bart , Ymeri Hasan , Maex Karen
Published: April 2024

In this paper, we present a new approach for capacitance matrix calculation of lossy multilayer VLSI interconnects based on quasi-static analysis and Fourier projection technique. The formulation is independent from the position of the interconnect conductors and number of layers in the structure, and is especially adequate to model 2D and 3D layered structures with planar boundaries. Thanks to the quasi-static algorithms considered for the capacitance analysis and the expansions in terms of convergent Fourier series the tool is reliable and very efficient; results can be obtained with relatively little programming effort. The validity of the technique is verified by comparing its results with on-surface MEI method, moment method for total charges in the structure, and CAD-oriented equivalent-circuit methodology, respectively.
On effectiveness of conditional admission control for IP QoS network services with REM scheme
Authors: Dabrowski Marek , Burakowski Wojciech , Beben Andrzej
Published: April 2024

Future IP QoS (quality of service) networks are aiming at differentiating transfer quality of packets belonging to different flows. For this purpose, a set of network services (NS) with different QoS objectives is defined and implemented in the network. To a NS a certain amount of network resources, i.e. dedicated link capacity with associated buffer size, is allocated. Moreover, the resources dedicated for one NS are not available for other NSs. Traditional approach for admission control algorithm corresponding to given NS takes into account current traffic conditions inside considered NS. This can lead to the situation, due to traffic fluctuations, that temporary overloaded NS cannot use the spare bandwidth from underloaded in this time other NSs. This paper describes a conditional admission control algorithm (C-AC),allowing us to admit new packet flow conditionally in the case where no available capacity inside a given NS. For conditionally accepted flow currently unused capacity, dedicated to other NS, is allocated. This can be done only in the case when QoS requirements for both the conditionally accepted flow and the flows in progress are satisfied. The conditions for effective using of C-AC algorithm are discussed in the paper, like characteristics of NS borrowing and lending capacity and their current traffic load. To show potential benefits of the approach, exemplary numerical results are included, corresponding to hypothetical NSs using REM (rate envelope multiplexing) scheme.
Greedy randomised adaptive search procedures for topological design of MPLS networks
Authors: Mysłek Andrzej
Published: April 2024

In this paper, the IP/MPLS network cost optimisation problem of selecting localisation of nodes and links, combined with link`s dimensioning, is discussed. As the considered problem is hard, we discuss and propose greedy randomised adaptive search procedure (GRASP) based solution method. GRASP is an iterative randomised sampling technique which combines adaptive randomised greedy function in constructing initial solution with local search optimisation. The effectiveness of the method is illustrated by means of a~numerical study. We compare the GRASP results with results for both exact and heuristic methods obtained in previous research concerning topological design problem.
Relations between ATM traffic parameters and quality of multimedia transmission - an experimental approach
Authors: Sochan Arkadiusz
Published: April 2024

In the paper, we present the results of research of MPEG-2 streams transmission through CBR and VBR channel in ATM network. We applied not only experimental and measurement methods but analytical ones as well. A description of the proposed measurement station includes: installed hardware, created software and prepared experimental data. Next, we present the applied measurement method. In the following section, we define a term of the quality of multimedia transmission. The measurement results were compared with the results of the analytical station model. We proposed a functional description of dependence between ATM traffic parameters, video stream bit rate, and quality of multimedia transmission.
AQUILA network architecture: first trial experiments
Authors: Bąk Andrzej , Bęben Andrzej , Burakowski Wojciech , Dąbrowski Marek , Fudała Monika , Tarasiuk Halina , Kopertowski Zbigniew
Published: April 2024

The paper presents trial experiments with IP QoS network services (NS) defined and implemented in the AQUILA pilot installation. The AQUILA NSs (premium CBR, premium VBR, premium multimedia and premium mission critical) provide a framework for supporting a variety of applications generating both streaming and elastic traffic. The measurement experiments confirm that AQUILA architecture differentiates the QoS offered to these NSs. The presented numerical results were obtained in the test network installed in the Polish Telecom (Warsaw) consisting of 8 CISCO routers.
Applications of commercial data analysis software for testing a telecommunications network
Authors: Paczocha Jerzy
Published: April 2024

This paper shows practical aspect in application commercial software to analysis data concerning information from telecommunication network. The following items are discussed: example of network estimation methodology, the main advantages of network testing system delivering information concerning quality of service (QoS) and network performance (NP) from the user`s perspective, general testing system description and data analysis model and example forms of presentation.
Decision support tool for web cache management
Authors: Pietrzykowski Jarosław
Published: April 2024

Web caching is the subject of intense research and development since it seems to be very promising area. Web caching means storing copies of frequently used objects (documents) geographically close to users requesting them to reduce network load, servers load and user response times. Cache can be situated in different locations between user and servers with original content. It seems that the most significant improvement can be achieved by using the proxy server -- a dedicated web server. Various parameters affect web cache performance: cache size, limitations on document sizes or documents removal policy. Several metrics are used to evaluate this performance: hit rate for example is the ratio of documents obtained by using the cache mechanism comparing to the total number of documents requested. Choosing adequate parameters for interesting traffic patterns to improve cache performance is not a trivial cache management problem. Prototype tool based on multicriteria model analysis and supporting such web cache management is presented. Simple case was examined where small number of sets of cache parameters (variants), miniature traffic representation and only two performance measures are considered.
A proposition to exploit the partially linear structure of the nonlinear multicommodity flow optimization problem
Authors: Białoń Paweł M.
Published: April 2024

Optimization problems arising in telecommunications are often large-scale nonlinear problems. Usually their big size is generated mainly by their linear parts but the existence of small or medium nonlinear parts prevents us from directly tackling them with linear solvers, which are efficient. Instead, the author has proposed a method to decompose big nonlinear problems into nonlinear and linear parts. Its coordination procedure uses two auxiliary solvers: quadratic and pure nonlinear. The procedure falls in the class of projection methods. Special cuts proposed by the author allow to avoid an excessive zigzagging while not enormously increasing the complexity of both the parts. The validity of these cuts can be analyzed within the framework of obtuse cone model. Here the author summarizes the method and analyses its applicability to nonlinear multicommodity flow problems. The structure and particular sizes of this problem make the method useful. The considerations are illustrated by a numerical example with a multicommodity flow problem.
On equitable approaches to resource allocation problems: the conditional minimax solutions
Authors: Ogryczak Włodzimierz , Śliwiński Tomasz
Published: April 2024

In this paper we introduce and analyze a solution concept of the conditional minimax as a generalization of the minimax solution concept extended to take into account the number of services (the portion of demand) related to the worst performances. Namely, for a specified portion of demand we take into account the corresponding portion of the maximum results and we consider their average as the worst conditional mean to be minimized. We show that, similar to the standard minimax approach, the minimization of the worst conditional mean can be defined by a linear objective and a number of auxiliary linear inequalities. We report some results of initial computational experience with the new solution concept.
Multi-agent utility theory for ethical conflict resolution
Authors: Tamura Hiroyuki
Published: April 2024

In this paper we try to construct a two-attribute group disutility function for two conflicting decision makers, taking into account the property of utility independence and/or convex dependence between them. Two variables in the group utility function are disutility levels of two conflicting decision makers. The disutility level of each decision maker is modeled using multiple attributes, that is disutility function of each decision maker is formulated as a multi-attribute disutility function. By using a~group disutility function for two conflicting agents, we can model the mutual concessions of the two conflicting agents taking into account ethical preference of each decision maker, and hence we can expect fairer multiple agents decision making for realizing better social welfare.
Effectiveness of active forgetting in machine learning applied to financial problems
Authors: Nakayama Hirotaka , Yoshii Kengo
Published: April 2024

One of main features in financial investment problems is that the situation changes very often over time. Under this circumstance, in particular, it has been observed that additional learning plays an effective role. However, since the rule for classification becomes more and more complex with only additional learning, some appropriate forgetting is also necessary. It seems natural that many data are forgotten as the time elapses. On the other hand, it is expected more effective to forget unnecessary data actively. In this paper, several methods for active forgetting are suggested. The effectiveness of active forgetting is shown by examples in stock portfolio problems.
Analytical properties of a stochastic teletraffic system with MMPP input and an access function
Authors: Tralh˜ao Lino , Craveirinha José , Cardoso Domingos
Published: April 2024

Stochastic modeling of teletraffic systems with restricted availability and correlated input arrival rates is of great interest in GoS (grade of service) analysis and design of certain telecommunication networks. This paper presents some analytical properties of a recursive nature, associated with the infinitesimal generator of the Markov process which describes the state of a teletraffic system with MMPP (Markov modulated Poisson process) input traffic, negative exponentially distributed service times, finite queue and restricted availability defined through a loss function. Also the possible application of the derived properties to a direct method of resolution of the linear system, which gives the stationary probability distribution of the system, will be discussed.
Existence results for a self-adjoint coupled system of nonlinear second-order ordinary differential inclusions with nonlocal integral boundary conditions
Authors: Ahmad Bashir , Almalki Amal , Ntouyas Sotiris , Alsaedi Ahmed
Published: April 2024

A coupled system of nonlinear self-adjoint second-order ordinary differential inclusions supplemented with nonlocal non-separated coupled integral boundary conditions on an arbitrary domain is studied. The existence results for convex and non-convex valued maps involved in the given problem are proved by applying nonlinear alternative of Leray-Schauder for multi-valued maps, and Covitz-Nadler's fixed point theorem for contractive multi-valued maps, respectively. Illustrative examples for the obtained results are presented. The paper concludes with some interesting observations.
On vertex-edge corona of graphs and its spectral polynomial
Authors: Patil Daneshwari , Ramane Harishchandra
Published: April 2024

Given a graph \(G_1\), the vertex-corona (corona) and the edge-corona focus only on vertices and edges respectively, in forming the corona product with other graphs. In the present work, we define a new corona by considering both vertices and edges simultaneously in forming the corona aproduct with other graphs, called vertex-edge corona. Further, we study the spectral polynomial for the vertex-edge corona of three arbitrary graphs, followed by some corollaries related to regular graphs for their spectrum, energy and equienergetic graphs.
Exploring new proofs for three important trigonometric inequalities
Authors: Shinde Rupali , Christophe Chesneau  , Darkunde Nitin
Published: April 2024

In this article, we present alternative proofs for three significant inequalities pertaining to various trigonometric functions. The cornerstone of these proofs lies in the utilization of Bernoulli's series expansions.
Polynomial stability of nonlinear Timoshenko system with distributed delay-time
Authors: Bouzettouta Lamine , Khochemane Houssem Eddine , Hebhoub Fahima
Published: April 2024

In this work, we consider a nonlinear Timoshenko system with distributed delay-time. We prove the polynomial stability of the system for the case of nonequal speeds of wave propagation. This is after verifying the exponential stability in the case of equal speeds.
On derivations and Lie structure of semirings
Authors: Dadhwal Madhu Bala , Neelam
Published: April 2024

In [8], Herstein introduced the notion of the Lie structure of associative rings and established the Lie type theory for rings. This paper extends these ring theoretical results and also extends some well known results of [3, 6, 7] in the framework of semirings, which are very important to investigate the Lie type theory of semirings and their higher commutators. Moreover, we characterize the Lie structure of semirings and thereby explore the action of derivations on Lie ideals of semirings.