Performance of the Product of Three Nakagami-m Random Variables

An output signal from a multi-section wireless relay communication system is equal to the product of the signal envelopes from individual sections. In this paper, a three-sections relay system is considered in the presence of Nakagami-m fading at each section. First, random variable (RV) is formed as the product of three Nakagami-m RVs. For such product, the moments are determined in the closed forms. The first moment is the mean of the signal; the second moment is the average power of the signal, and the third moment is skewness. Then, the Amount of Fading (AoF) is calculated. AoF is a measure of the severity effect of fading in a particular channel model. Besides, all system performance are shown graphically and the parameters influence has been analyzed and discussed

Application of the S690QL class steels in responsible welded structures

In this paper are considered the most important properties of a special class of high strength steels S690QL, which can be classified into the group of special low alloyed steels. The high strength steels belong into a group of high quality steels. They possess exceptional mechanical properties, especially tensile strength and toughness. Those favorable properties are being achieved by application of special procedures of thermo-mechanical processing and simultaneous alloying with adequate elements. The advantages that the S690QL steels have with respect to other steels are being presented here. However, possibilities for application of those steels in responsible welded structures are limited due to their only relatively good weldability.  The special procedures for improving it are discussed here, primarily preheating, controlled heat input during welding and additional heat treatment of the welded joint

Application of the S690QL class steels in responsible welded structures

In this paper are considered the most important properties of a special class of high strength steels S690QL, which can be classified into the group of special low alloyed steels. The high strength steels belong into a group of high quality steels. They possess exceptional mechanical properties, especially tensile strength and toughness. Those favorable properties are being achieved by application of special procedures of thermo-mechanical processing and simultaneous alloying with adequate elements. The advantages that the S690QL steels have with respect to other steels are being presented here. However, possibilities for application of those steels in responsible welded structures are limited due to their only relatively good weldability.  The special procedures for improving it are discussed here, primarily preheating, controlled heat input during welding and additional heat treatment of the welded joint

First and Second Order Characteristics of a Wireless Three-hop Relay Channel with the Presence of Rayleigh Fading, Journal of Telecommunications and Information Technology, 2020, nr 2

In this paper, a wireless three-hop relay communication system operating in a Rayleigh multipath fading environment is analyzed. The output signal from such a system is a product of signal envelopes from all sections, meaning that it is actually a product of three random variables (RVs) with Rayleigh distribution. We considered here the first-order characteristics: probability density function (PDF), cumulative distribution function and outage probability (OP). Then, the moments and amount of fading (AoF) were derived in the closed forms. The second order characteristics we present include the following: level crossing rate (LCR) and average fade duration (AFD). A few graphs are given to show the impact of the specific parameters of the wireless three-hop relay syste

Product of Three Random Variables and its Application in Relay Telecommunication Systems in the Presence of Multipath Fading, Journal of Telecommunications and Information Technology, 2019, nr 1

In this paper, the product of three random variables (RVs) will be considered. Distribution of the product of independent random variables is very important in many applied problems, including wireless relay telecommunication systems. A few of such products of three random variables are observed in this work: the level crossing rate (LCR) of the product of a Nakagami-m random variable, a Rician random variable and a Rayleigh random variable, and of the products of two Rician RVs and one Nakagami-m RV is calculated in closed forms and presented graphically. The LCR formula may be later used for derivation of average fade duration (AFD) of a wireless relay communication radio system with three sections, working in the multipath fading channel. The impact of fading parameters and multipath fading power on the LCR is analyzed based on the graphs presented

a rare case of pacemaker lead endocarditis successfully treated with open heart surgery

Background: Cardiac device-related endocarditis has emerged as a serious complication in the era of advanced medical technology. Pacemaker related infections are rare and life-threatening with incidence from 0.06% to 7% and high mortality rate (30-35%). Diagnosis is hard, frequently delayed and could be even missed due to poor clinical findings. The average delay in diagnosis is 5.5 month. We report a case of the late-onset of pacemaker lead endocarditis caused by S. epidermidis successfully treated with open heart surgery. Case Report: Patient with persistent high fever for 11 month and suspicion for infective endocarditis was admitted in Cardiovascular Institute. No clinical signs of endocarditis were observed. TTE revealed large vegetation 30 × 17 mm attached to the atrial electrodes with high embolic potential. This finding was verified by transesophageal echocardiography (TEE), although CT scan did not reveal vegetation. Blood cultures were negative. A sternotomy with cardiopulmonary bypass was performed and electrodes were extracted with large vegetation. Intraoperative finding revealed large thrombus with vegetation around pacemaker leads. Cultures of the electrodes and vegetation revealed Staphylococcus epidermidis. Surgery was followed up with antibiotic treatment for 6 weeks. He has been followed up for the next 2 years, and without complications. Conclusion: The absence of criteria for endocarditis and negative blood cultures should not keep the physician from ruling out lead endocarditis. This complication carries high risk of mortality if left untreated

Identification of Nonlinear Systems Using the Hammerstein-Wiener Model with Improved Orthogonal Functions

Hammerstein-Wiener systems present a structure consisting of three serial cascade blocks. Two are static nonlinearities, which can be described with nonlinear functions. The third block represents a linear dynamic component placed between the first two blocks. Some of the common linear model structures include a rational-type transfer function, orthogonal rational functions (ORF), finite impulse response (FIR), autoregressive with extra input (ARX), autoregressive moving average with exogenous inputs model (ARMAX), and output-error (O-E) model structure. This paper presents a new structure, and a new improvement is proposed, which is consisted of the basic structure of Hammerstein-Wiener models with an improved orthogonal function of Müntz-Legendre type. We present an extension of generalised Malmquist polynomials that represent Müntz polynomials. Also, a detailed mathematical background for performing improved almost orthogonal polynomials, in combination with Hammerstein-Wiener models, is proposed. The proposed approach is used to identify the strongly nonlinear hydraulic system via the transfer function. To compare the results obtained, well-known orthogonal functions of the Legendre, Chebyshev, and Laguerre types are exploited

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Cardiopoietic cell therapy for advanced ischemic heart failure: results at 39 weeks of the prospective, randomized, double blind, sham-controlled CHART-1 clinical trial

Cardiopoietic cells, produced through cardiogenic conditioning of patients' mesenchymal stem cells, have shown preliminary efficacy. The Congestive Heart Failure Cardiopoietic Regenerative Therapy (CHART-1) trial aimed to validate cardiopoiesis-based biotherapy in a larger heart failure cohort

Discutindo a educação ambiental no cotidiano escolar: desenvolvimento de projetos na escola formação inicial e continuada de professores

A presente pesquisa buscou discutir como a Educação Ambiental (EA) vem sendo trabalhada, no Ensino Fundamental e como os docentes desta escola compreendem e vem inserindo a EA no cotidiano escolar., em uma escola estadual do município de Tangará da Serra/MT, Brasil. Para tanto, realizou-se entrevistas com os professores que fazem parte de um projeto interdisciplinar de EA na escola pesquisada. Verificou-se que o projeto da escola não vem conseguindo alcançar os objetivos propostos por: desconhecimento do mesmo, pelos professores; formação deficiente dos professores, não entendimento da EA como processo de ensino-aprendizagem, falta de recursos didáticos, planejamento inadequado das atividades. A partir dessa constatação, procurou-se debater a impossibilidade de tratar do tema fora do trabalho interdisciplinar, bem como, e principalmente, a importância de um estudo mais aprofundado de EA, vinculando teoria e prática, tanto na formação docente, como em projetos escolares, a fim de fugir do tradicional vínculo “EA e ecologia, lixo e horta”.Facultad de Humanidades y Ciencias de la Educació