bluuebunny/crossref_metadata_2025 huggingface dataset:
Reliability and validity study of the Spanish adaptation of the “Wijma Delivery Expectancy/Experience Questionnaire” (W-DEQ-A)
Authors: Ortega-Cejas Celia Maria , Roldán-Merino Juan , Lluch-Canut Teresa , Castrillo-Pérez Mª Isabel , Vicente-Hernández Mª Mercedes , Jimenez-Barragan Marta , Biurrun-Garrido Ainoa , Farres-Tarafa Mariona , Casas Irma , Cabrera-Jaime Sandra
Published: March 2021

The Wijma Delivery Expectancy/Experience Questionnaire (W-DEQ-A) is an instrument that evaluates fear of childbirth through the expectations of women in relation to childbirth and their experience during the birth. The objective of this study was to translate the W-DEQ-A into Spanish and analyse its reliability and validity. The study was carried out in two phases: (1) adapting the questionnaire to Spanish and (2) a transversal study in a sample of 273 pregnant women in the Sexual and Reproductive Health centres in the Metropolitan Northern Barcelona in Catalonia (Spain). The psychometric properties were analysed in terms of reliability and construct validity. The confirmatory factorial analysis did not confirm the unidimensionality of the original structure of the WDEQ-A, as happened with the other studies in which it has previously been validated. The result of the exploratory factorial analysis suggests four factors, or dimensions, very similar but not identical to those obtained in other analysis studies of the W-DEQ-A. The Cronbach alpha and the omega scale were also adequate for all the scales and for each of the dimensions. The results of this study confirm the findings of other studies that suggest that the W-DEQ-A is multi-dimensional. In the Spanish version of the W-DEQ-A four dimensions have been identified to explore fear of childbirth in pregnant women. The Spanish version of the WDEQ-A (WDEQ-A-Sp) is reliable and valid for the measurement of fear of childbirth in clinical practice and for use in future research.
Experimental design, formulation and in vivo evaluation of a novel topical in situ gel system to treat ocular infections
Authors: Nair Anroop B. , Shah Jigar , Jacob Shery , Al-Dhubiab Bandar E. , Sreeharsha Nagaraja , Morsy Mohamed A. , Gupta Sumeet , Attimarad Mahesh , Shinu Pottathil , Venugopala Katharigatta N.
Published: March 2021

In situ gels have been extensively explored as ocular drug delivery system to enhance bioavailability and efficacy. The objective of present study was to design, formulate and evaluate ion-activated in situ gel to enhance the ocular penetration and therapeutic performance of moxifloxacin in ophthalmic delivery. A simplex lattice design was utilized to examine the effect of various factors on experimental outcomes of the in situ gel system. The influence of polymers (independent variables) such as gellan gum (X1), sodium alginate (X2), and HPMC (X3) on gel strength, adhesive force, viscosity and drug release after 10 h (Q10) were assessed. Selected formulation (MH7) was studied for ex vivo permeation, in vivo irritation and pharmacokinetics in rabbits. Data revealed that increase in concentration of polymers led to higher gel strength, adhesive force and viscosity, however, decreases the drug release. MH7 exhibited all physicochemical properties within acceptable limits and was stable for 6 months. Release profile of moxifloxacin from MH7 was comparable to the check point batches and followed Korsmeyer-Peppas matrix diffusion-controlled mechanism. Ocular irritation study signifies that selected formulation is safe and non-irritant for ophthalmic administration. In vivo pharmacokinetics data indicates significant improvement of moxifloxacin bioavailability (p < 0.0001) from MH7, as evidenced by higher Cmax (727 ± 56 ng/ml) and greater AUC (2881 ± 108 ng h/ml), when compared with commercial eye drops (Cmax; 503 ± 85 ng/ml and AUC; 978 ± 86 ng h/ml). In conclusion, developed in situ gel system (MH7) could offers a more effective and extended ophthalmic therapy of moxifloxacin in ocular infections when compared to conventional eye drops.
Determinants of compliance to the facemask directive in Greece: A population study
Authors: Labiris Georgios , Panagiotopoulou Eirini-Kanella , Perente Asli , Chatzimichael Eleftherios , Fotiadis Ioannis , Taliantzis Sergios , Konstantinidis Aristeidis , Dardabounis Doukas
Published: March 2021

Purpose

Primary objective of this study was to identify potential difficulties and/or discomfort when using a facemask. Moreover, to explore the impact of spectacles, contact lenses and visual acuity on the compliance to the facemask directive.

Methods

This is a prospective study that was conducted at the Department of Ophthalmology, University Hospital of Alexandroupolis, Greece between June 2020 and August 2020. Greek speaking citizens with permanent residency in Greece above 18 years old were included. A custom questionnaire (DeMask-20) was constructed and validated, which pertained to the perceived difficulty and discomfort when using a facemask. It contained 20 items grouped in 8 subscales (driving, near vision, distance vision, ocular discomfort, role limitation, collaboration, dependency on others, emotional stress). Perceived difficulty and discomfort when using a facemask, compliance and correlations of compliance with DeMask-20 scores, demographics, spectacle and/or contact lens use, and visual acuity were evaluated.

Results

The number of factors was determined through factor analysis. Cronbach’s alpha ranged from 0.716 for the “Role limitation” subscale to 0.938 for “Ocular discomfort” subscale. 1,214 participants (402 men, 812 women, mean age 36.79±12.50 years) completed the DeMask-20 instrument. Mean DeMask-20 score of all study participants was 3.79±0.71. Significant differences in DeMask-20 score were detected in gender (p = 0.009), spectacle use (p = 0.034), contact lens use (p = 0.049), and binocular distance visual acuity (bDVA) (p = 0.001). Mean compliance of all participants was 4.05±0.96. Men, people <50 years and spectacle wearers showed significantly worse compliance (p<0.05). Moreover, professional workers and professional drivers demonstrated significantly better compliance (p = 0.008 and p = 0.047). Significant correlation was detected between compliance and DeMask-20 score (p<0.001, R2 = 0.471). Significant correlations were detected with driving, near vision, distance vision, collaboration, role limitation, emotional stress (p<0.05, R2: 0.386–0.493).

Conclusions

Factor analysis suggested that the DeMask-20 instrument demonstrates adequate validity, while Cronbach’s alpha indicated sufficient internal consistency of all subscales. This study provided the necessary methods that could evaluate compliance trends and the efficacy of healthcare interventions against COVID-19. Our outcomes suggest that young males who use spectacles should be targeted by Greek Healthcare authorities in order to improve compliance rates.
The experience of care partners of patients with Parkinson’s disease psychosis
Authors: Mantri Sneha , Klawson Emily , Albert Steven , Rapoport Robyn , Precht Chelle , Glancey Sarah , Daeschler Margaret , Mamikonyan Eugenia , Kopil Catherine M. , Marras Connie , Chahine Lana M.
Published: March 2021

Background

Parkinson’s disease psychosis (PDP) has a major impact on quality of life and care partner burden; however, little is known about the lived experiences of care partners in managing PDP.

Objective

To understand how care partners of individuals with PDP experience their role and articulate their needs related to psychosis.

Methods

This was a qualitative study of semi-structured telephone interviews. Recruitment was conducted online via the clinical study matching tool, Fox Trial Finder; study activities took place remotely via telephone interviews. Transcripts of the phone interviews were analyzed by grounded theory methods, and a codebook of key themes that emerged from the analysis was developed.

Results

Nine care partners (all female) were interviewed. Discussion topics in the codebook included (1) care partner burden and guilt; (2) communication with medical professionals; (3) coping strategies; (4) emotional reactions of the care partner to psychosis; (5) sources of knowledge about PD psychosis; (6) attitudes towards medications for PDP; (7) strategies to care for loved ones with psychosis; (8) psychosis triggers.

Conclusions

This qualitative analysis uncovers important aspects of the care partner experience, including challenges in navigating the medical system and communicating with professionals. Providers treating patients with PDP should be aware of these constraints and provide added support for strained care partners.
SARS-CoV-2 outbreak in a tri-national urban area is dominated by a B.1 lineage variant linked to a mass gathering event
Authors: Stange Madlen , Mari Alfredo , Roloff Tim , Seth-Smith Helena MB , Schweitzer Michael , Brunner Myrta , Leuzinger Karoline , Søgaard Kirstine K. , Gensch Alexander , Tschudin-Sutter Sarah , Fuchs Simon , Bielicki Julia , Pargger Hans , Siegemund Martin , Nickel Christian H. , Bingisser Roland , Osthoff Michael , Bassetti Stefano , Schneider-Sliwa Rita , Battegay Manuel , Hirsch Hans H. , Egli Adrian
Published: March 2021

The first case of SARS-CoV-2 in Basel, Switzerland was detected on February 26th 2020. We present a phylogenetic study to explore viral introduction and evolution during the exponential early phase of the local COVID-19 outbreak from February 26th until March 23rd. We sequenced SARS-CoV-2 naso-oropharyngeal swabs from 746 positive tests that were performed at the University Hospital Basel during the study period. We successfully generated 468 high quality genomes from unique patients and called variants with our COVID-19 Pipeline (COVGAP), and analysed viral genetic diversity using PANGOLIN taxonomic lineages. To identify introduction and dissemination events we incorporated global SARS-CoV-2 genomes and inferred a time-calibrated phylogeny. Epidemiological data from patient questionnaires was used to facilitate the interpretation of phylogenetic observations. The early outbreak in Basel was dominated by lineage B.1 (83·6%), detected first on March 2nd, although the first sample identified belonged to B.1.1. Within B.1, 68·2% of our samples fall within a clade defined by the SNP C15324T (‘Basel cluster’), including 157 identical sequences at the root of the ‘Basel cluster’, some of which we can specifically trace to regional spreading events. We infer the origin of B.1-C15324T to mid-February in our tri-national region. The other genomes map broadly over the global phylogenetic tree, showing several introduction events from and/or dissemination to other regions of the world via travellers. Family transmissions can also be traced in our data. A single lineage variant dominated the outbreak in the Basel area while other lineages, such as the first (B.1.1), did not propagate. A mass gathering event was the predominant initial source of cases, with travel returners and family transmissions to a lesser extent. We highlight the importance of adding specific questions to epidemiological questionnaires, to obtain data on attendance of large gatherings and their locations, as well as travel history, to effectively identify routes of transmissions in up-coming outbreaks. This phylogenetic analysis in concert with epidemiological and contact tracing data, allows connection and interpretation of events, and can inform public health interventions.

Trial Registration: ClinicalTrials.gov NCT04351503.
Conflictos socioambientales en la pesca del mapará (Hypophthalmus marginatus): efectos de la represa Tucuruí
Authors: Da Silva Holanda Bianca , Barbosa Magalhães Sônia , Da Silva Martins Paulo Fernando , Vasconcelos Simões Aquiles
Published: March 2021

Este artículo busca mostrar cómo los cambios ambientales derivados de la construcción de la represa Tucuruí están en la base de los conflictos entre los pescadores artesanales del Bajo Tocantins. La investigación de campo se llevó a cabo en la isla Saracá. Se observó que la desecación, el cambio en el flujo y el pulso artificial del río Tocantins y sus afluentes, así como los cambios en las características del agua y las alteraciones en la morfología de la isla de Saracá, dieron lugar a la pérdida de especies, reducción en la captura de peces y obsolescencia de los equipos de pesca, con importantes consecuencias sobre el territorio pesquero y las relaciones sociales locales. Se redefinieron los lugares de pesca del mapará (Hypophthalmus marginatus), la movilidad de los pescadores y las relaciones sociales entre los pescadores profesionales y la comunidad local. A través de los denominados acuerdos de pesca, las comunidades y los pescadores, en particular, intentan adaptarse a la nueva temporalidad y a las nuevas dinámicas sociales.
Sobre la no aplicación de la sentencia de la Corte Interamericana en el caso Herzog por los tribunales brasileños
Authors: Berdugo Gómez de la Torre Ignacio
Published: March 2021

El artículo analiza la resolución judicial que rechaza la denuncia, presentada por el Ministerio Público brasileño para dar cumplimiento a la sentencia de la Corte Interamericana de Derechos Humanos en el caso Herzog. Se analiza la pretendida validez de la ley de amnistía, la consideración de los hechos como crimen de lesa humanidad y los problemas que presenta en Brasil la relación entre Derecho penal internacional y el Derecho nacional.
Ixekizumab Associated New-Onset Inflammatory Bowel Disease
Authors: Nazarian Amir , Grin Andrea , Wijeratne Don Thiwanka
Published: March 2021

Ixekizumab is a monoclonal antibody targeting interleukin-17 approved for the treatment of psoriasis. In a recent post hoc meta-analysis of Phase-I to Phase-III clinical trials of anti-interleukin-17 agents for the treatment of plaque psoriasis, there was a rare association (<1%) with induction or exacerbation of inflammatory bowel disease. We report a case of new-onset ileal Crohn's disease in a 48-year-old woman on ixekizumab for psoriasis.
Lung Metastasis Postradioembolization of Hepatocellular Carcinoma With Tumor in Vein
Authors: Kapoor Harit , Sanampudi Sreeja , Owen Joseph , Raissi Driss
Published: March 2021

Transarterial radioembolization (TARE) is one of the few treatment options available for infiltrative hepatocellular carcinoma with tumor in vein. This is backed by the published data showing marginally favorable toxicity profile compared with other locoregional and systemic therapies. Although lung shunt fraction studies are performed to prevent radiation injury to the lungs, TARE-induced embolization/metastasis to the lungs has not been reported before. We report an intriguing case of new lung metastases within 1 month after TARE for infiltrative hepatocellular carcinoma with a tumor in the vein, with only a slightly elevated but acceptable lung shunt fraction. This report brings to light the possibility of such a complication and argues for improved preprocedural assessment of a tumor in vein burden and embolization potential.
Vanishing Bile Duct Syndrome Preceding the Diagnosis of Hodgkin Lymphoma
Authors: Anugwom Chimaobi , Goetz Grete , Hassan Mohamed
Published: March 2021

Vanishing bile duct syndrome is an acquired liver disease characterized by the progressive destruction and loss of intrahepatic bile ducts. It usually signifies end-stage cholestatic liver disease and is characterized by ductopenia on liver biopsy specimen. We present a case of vanishing bile duct syndrome as the presenting symptom in a patient with Hodgkin lymphoma with subsequent improvement after adequate treatment of the lymphoma.
Influence of Oxidation Media on the Transport Properties of Thin Oxide Layers of Zirconium Alloys
Authors: Frank H.
Published: March 2021

Two batches of tubes of Zr1Nb and of Zry-4W were oxidized for 30 days at 425 °C in steam, and for 360 days at 500 °C in air, respectively. The analysis of the I-V characteristics at constant temperatures up to 220 °C of oxide layers of nearly equal thickness gave an activation energy of 1,3 eV for the grey homogeneous steam samples, and of 0.4 eV for the white surface layer, and of 1.3 eV at temperatures over 140 °C, for the grey bottom layer of the air samples, respectively. The I-V characteristics were sub-linear in the air samples, the current growing less at rising voltages, but staightening to super-linear space-charge limited currents at higher temperatures. The injection currents flowing when voltage was applied did not reach constant equilibrium, but at a bend, continued with a lesser slope. The resistivity was about one order of magnitude greater in air samples and greater in Zry-4W. The relative permittivity was greater in the steam samples and greater in Zr1Nb. The currents of the air samples were greater with Au electrodes than with Ag electrodes.
EU Emissions Trading Scheme as Implemented in the Czech Republic
Authors: Chmelík T. , Zámyslický P.
Published: March 2021

The paper reports on the implementation of the European Emissions Trading Scheme (EU ETS) in the Czech Republic. Trading in CO2 emission allowances is one of the most dynamic and progressive economic instruments of environmental policy. Since coming into force in January 2005, the system has incorporated into company decision making a truly new phenomenon – the price of carbon in the form of allowances tradable on the European market, where the price of the allowance represents the costs of a company when emitting one ton of CO2. The incentive, given by the opportunity costs should motivate operators of installations emitting CO2 to analyze options for carbon emission reduction and to behave rationally. In total, the system should result in a quite significant reduction in the compliance costs of CO2 reduction when compared to alternatives such as taxes or emission limits, as a result of flexibility given by the market.The most controversial and sensitive part of the system is the initial distribution of the allowances to emitters. The so-called National Allocation Plan has to provide answers to very difficult questions – to whom, how and how many allowances will be given. This paper focuses on a detailed description of the sectors and companies in the Czech Republic that are affected by the system and discusses various aspects of the scheme.
Single-Phase Pulse Width Modulated Rectifier
Authors: Bauer J.
Published: March 2021

The PWM rectifier is a very popular topic nowadays. With the expansion of electronics, conversion of electric parameters is also needed. For this purpose the side effects of passive rectifiers, e.g. production of harmonics and reactive power, must be taken into account. All these side effects fall away with the application of PWM rectifiers. This paper compares the differences between a phase angle controlled rectifier and a PWM rectifier.
Modeling Water Pollution of Soil
Authors: Doležel V. , Procházka P. , Křístek V.
Published: March 2021

The government of the Czech Republic decided that in the location to the west of Prague, capital city of the Czech Republic, some deep mines should be closed because of their low efficiency of coal mined i.e. small amounts and low quality of the coal extracted in the final stage of mining. The locations near Prague influenced the decision to do maintenance on the abandoned mines, as the thread of soil pollution was unacceptably high in the neighborhood of the capital city. Before the mines were closed it was necessary to separate existed extensive horizontal location of salt water below a clay layer in order not to deteriorate the upper fresh water. The salt water could not be allowed to pollute the upper layer with the fresh water, as many wells in villages in the neighborhood of the former mines would be contaminated. Two horizontal clay layers (an insulator and a semi-insulator) separated the two horizons containing salt water and fresh water. Before starting deep mining, vertical shafts had to be constructed with concrete linings to enable the miners to access the depths. The salt water was draining away throughout the existence of the mine. The drainage was designed very carefully to avoid possible infiltration of salt water into the upper horizon. Before the mines were abandoned it was necessary to prevent contact between the two kinds of waters in the shafts. Several options were put forward, the most efficient of which appeared to be one that proposed filling the shafts with spoil soil and creating a joint seal made of disparate material at the interface between the salt water and fresh water to create a reliable stopper. The material for the spoil soil was delivered from deposits located not far from the shafts. This material consisted of a variety of grains of sand, big boulders of slate, slaty clay, sandstone, etc.. Chemical admixtures were considered to improve the flocculation of the filling material. The stopper was positioned at a depth of 220–300 m below the terrain. As an alternative, thinner stoppers were considered, but this option was discarded.The aim of this paper is to describe the design of the stoppers applied to separate the two types of water along the contact horizon using Desai’s DSC theory (Distinct State Concept), and generalized plane strain in the multiphase problem of water flow in a porous medium. In addition, a comparison of some results from scale experimental models with numerical solutions was carried out. The intrinsic material properties of stoppers for numerical computations were obtained from physical and chemical laboratory tests. The models were evaluated for the complete underground work, particularly in its final stage of construction.
An Empirical Method for Estimating Global Solar Radiation over Egypt
Authors: Khalil S. A. , Fathy A. M.
Published: March 2021

Global solar radiation has been estimated on the basis of measurements of sunshine duration for different selected sites in Egypt; (Marsa-Matruh, Cairo, Aswan, Al-Kharga, Abu-Simble and Halaib-Shalatin). The regression coefficients (a) and (b) of Angstrom type correlation are calculated for the selected sites. The values of the regression coefficients are found to vary from 0.219–0.611 and 0.107–0.576, respectively. These values have been calculated by three different approaches. The estimated values of the global solar radiation are compared with the measured values. Although the (a) and (b) values differ from one site to another; the summation (a+b) is almost the same for the selected sites. The difference between the estimated and measured values of the global solar radiation at the various sites varies from 4 % to 12 %.
Compressive behaviour at High Temperatures of Fibre Reinforced Concretes
Authors: Santos S. O. , Rodrigues J. P. C. , Toledo R. , Velasco R. V.
Published: March 2021

This paper summarizes the research that is being carried out at the Universities of Coimbra and Rio de Janeiro, on fibre reinforced concretes at high temperatures. Several high strength concrete compositions reinforced with fibres (polypropylene, steel and glass fibres) were developed. The results of compressive tests at high temperatures (300 °C, 500 °C and 600 °C) and after heating and cooling down of the concrete are presented in the paper. In both research studies, the results indicated that polypropylene fibers prevent concrete spalling.
Investigation into Methods for Predicting Connection Temperatures
Authors: Anderson K. , Gillie M.
Published: March 2021

The mechanical response of connections in fire is largely based on material strength degradation and the interactions between the various components of the connection. In order to predict connection performance in fire, temperature profiles must initially be established in order to evaluate the material strength degradation over time. This paper examines two current methods for predicting connection temperatures: The percentage method, where connection temperatures are calculated as a percentage of the adjacent beam lower-flange, mid-span temperatures; and the lumped capacitance method, based on the lumped mass of the connection. Results from the percentage method do not correlate well with experimental results, whereas the lumped capacitance method shows much better agreement with average connection temperatures. A 3D finite element heat transfer model was also created in Abaqus, and showed good correlation with experimental results.
Connections of Trapezoidal Sheets under Fire
Authors: Kallerová P. , Wald F. , Sokol Z.
Published: March 2021

This paper describes two different experiments on connections of trapezoidal sheets under elevated temperatures. The first experiments were tensile tests carried out on four sets of tests with screwed connections under ambient and elevated temperatures. One diameter of self-drilling screws and three different thicknesses of trapezoidal sheets were used. The applied screws were without washers, or with sealed or steel washers. The second experiment was performed in a laboratory furnace to check the catenary action of a thin-walled trapezoidal sheet. The basic theory tested in this experiment was that in the first phase of the fire the sheet behaves as a simply supported beam, while in the second phase the load bearing is transferred by a tension membrane. These experiments will be used to develop a design model of connections at high temperatures. High fire resistance of the trapezoidal sheet, dependent on suitable design of the screwed connection to the bearing structure, was confirmed. The experiment with the simple beam also confirmed catenary action.
Multi-Condition Training for Unknown Environment Adaptation in Robust ASR Under Real Conditions
Authors: Rajnoha J.
Published: March 2021

Automatic speech recognition (ASR) systems frequently work in a noisy environment. As they are often trained on clean speech data, noise reduction or adaptation techniques are applied to decrease the influence of background disturbance even in the case of unknown conditions. Speech data mixed with noise recordings from particular environment are often used for the purposes of model adaptation. This paper analyses the improvement of recognition performance within such adaptation when multi-condition training data from a real environment is used for training initial models. Although the quality of such models can decrease with the presence of noise in the training material, they are assumed to include initial information about noise and consequently support the adaptation procedure. Experimental results show significant improvement of the proposed training method in a robust ASR task under unknown noisy conditions. The decrease by 29 % and 14 % in word error rate in comparison with clean speech training data was achieved for the non-adapted and adapted system, respectively.
Technical Evolution of Medical Endoscopy
Authors: Gross S. , Kollenbrandt M.
Published: March 2021

This paper gives a summary of the technical evolution of medical endoscopy. The first documented redirection of sunlight into the human body dates back to the 16th century. Rigid tubes with candle light were given a trial later on. Low light intensity forced the development of alternative light sources. Some of these experiments included burning chemical components. Electric lighting finally solved the problems of heat production and smoke. Flexible endoscopy increased the range of medical examinations as it allowed access to tight and angular body cavities. The first cameras for endoscopic applications made taking photos from inside the human body possible. Later on, digital video endoscopy made endoscopes easier to use and allowed multiple spectators to observe the endoscopic intervention. Swallowable capsules called pill-cams made endoscopic examinations of the small intestine possible. Modern technologies like narrow band imaging and fluorescence endoscopy increased the diagnostic significance of endoscopic images. Today, image processing is applied to decrease noise and enhance image quality. These enhancements have made medical endoscopy an invaluable tool in many diagnostic processes. In closing, an example is given of an interdisciplinary examination, which is taken from the archaeological field.
Shear Strengthening of Reinforced Concrete Beams Using GFRP Wraps
Authors: Saafan M. A. A.
Published: March 2021

The objective of the experimental work described in this paper was to investigate the efficiency of GFRP composites in strengthening simply supported reinforced concrete beams designed with insufficient shear capacity. Using the hand lay-up technique, successive layers of a woven fiberglass fabric were bonded along the shear span to increase the shear capacity and to avoid catastrophic premature failure modes. The strengthened beams were fabricated with no web reinforcement to explore the efficiency of the proposed strengthening technique using the results of control beams with closed stirrups as a  web reinforcement. The test results of 18 beams are reported, addressing the influence of different shear strengthening schemes and variable longitudinal reinforcement ratios on the structural behavior. The results indicated that significant increases in the shear strength and improvements in the overall structural behavior of beams with insufficient shear capacity could be achieved by proper application of GFRP wraps.
Mixture Based Outlier Filtration
Authors: Pecherková P. , Nagy I.
Published: March 2021

Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers.
Problems in Different Measuring and Assessment the Modulus of Deformation Using the Czech and German Methodologies
Authors: Lidmila M. , Horníček L. , Krejčiříková H. , Tyc P.
Published: March 2021

Comparative laboratory and in-situ measurements were used to establish the relationships between the static moduli of deformation calculated under the ED methodology and the DB methodology. The measurements proved that the moduli of deformation determined in accordance with the two methodologies cannot be substituted for each other.
Supply Chain in Electro-Energetics and Real Options
Authors: Drahovzal O.
Published: March 2021

This paper deals with determining the value of the connection in the supply chain in electro-energetics. First, useful connection options are described. The principle of deviations in the energetic system is then briefly described, and examples of their histories are shown in a chart. Next methods for evaluating the acquisition of a connection with the producer of electricity are explained. The simple classical approach to the problem and the real options approach are described. The real options approach is considered to be the most correct, providing the most realistic results. Then there is an example of a calculation for a company, and certain values for the prices of deviations are calculated and shown. Finally, a comparison of the results is made, and their consequences for the decision process are explained.
Removal of Specular Reflections in Endoscopic Images
Authors: Stehle T.
Published: March 2021

During an endoscopic examination, pictures from the inside of the human body are displayed on a computer monitor. Disturbing light reflections are often visible in these images. In this paper, we present an approach for removing these reflections and replacing them by an estimate obtained using a spectral deconvolution algorithm.
A Digital Loudspeaker: Experimental Construction
Authors: Valoušek P.
Published: March 2021

To verify the principal functionality of a digital loudspeaker the experimental construction of a digital loudspeaker was designed. This system consists of signal processing unit and transducer array. Both parts offer 8-bit precision and wide a spectrum of sampling frequencies. The signal processing unit is based on a programmable logic device which provides a flexible system for preparing a driving signal. The transducer array is formed by conventional dynamic transducers arranged in a circle. The initial measurements and listening tests provide acceptable results that are valuable for further digital loudspeaker developments.
Directional Loudspeaker Using a Parametric Array
Authors: Ritty A.
Published: March 2021

The theory for sound reproduction of parametric arrays is based on nonlinear acoustics. Due to the nonlinearity of the air, a finite amplitude ultrasound interacts with itself and generates audible secondary waves in the sound beam. A special feature of this loudspeaker is its sharper directivity compared to conventional loudspeakers of the same aperture size.This paper describes the basis of the theory used for parametric arrays, and presents the influence of the main parameters, e.g., carrier frequency. It also describes some signal pre-processing needed to obtain the desired audible sound. A PVDF (polyvinylidenefluoride) film transducer is also studied in order to produce a prototype to confirm the theory.
Robust Watermarking of Video Streams
Authors: Polyák T.
Published: March 2021

In the past few years there has been an explosion in the use of digital video data. Many people have personal computers at home, and with the help of the Internet users can easily share video files on their computer. This makes possible the unauthorized use of digital media, and without adequate protection systems the authors and distributors have no means to prevent it.Digital watermarking techniques can help these systems to be more effective by embedding secret data right into the video stream. This makes minor changes in the frames of the video, but these changes are almost imperceptible to the human visual system. The embedded information can involve copyright data, access control etc. A robust watermark is resistant to various distortions of the video, so it cannot be removed without affecting the quality of the host medium. In this paper I propose a video watermarking scheme that fulfills the requirements of a robust watermark.
Intelligent Support for a Computer Aided Design Optimisation Cycle
Authors: Dolšak B. , Novak M. , Kaljun J.
Published: March 2021

It is becoming more and more evident that  adding intelligence  to existing computer aids, such as computer aided design systems, can lead to significant improvements in the effective and reliable performance of various engineering tasks, including design optimisation. This paper presents three different intelligent modules to be applied within a computer aided design optimisation cycle to enable more intelligent and less experience-dependent design performance.
Advanced Load Effect Model for Probabilistic Structural Design
Authors: Sýkora M.
Published: March 2021

In probabilistic structural design some actions on structures can be well described by renewal processes with intermittencies. The expected number of renewals for a given time interval and the probability of “on“-state at an arbitrary point in time are of a main interest when estimating the structural reliability level related to the observed period. It appears that the expected number of renewals follows the Poisson distribution. The initial probability of “on”-state is derived assuming random initial conditions. Based on a two-state Markov process, the probability of “on”-state at an arbitrary point in time then proves to be a time-invariant quantity under random initial conditions. The results are numerically verified by Monte Carlo simulations. It is anticipated that the proposed load effect model will become a useful tool in probabilistic structural design. The aims of future research are outlined in the conclusions of the paper.
Numerical Simulation of Nanoscale Double-Gate MOSFETs
Authors: Stenzel R. , Müller L. , Herrmann T. , Klix W.
Published: March 2021

The further improvement of nanoscale electron devices requires support by numerical simulations within the design process. After a brief description of our SIMBA 2D/3D-device simulator, the results of the simulation of DG-MOSFETs are represented. Starting from a basic structure with a gate length of 30 nm, the model parameters were calibrated on the basis measured values from the literature. Afterwards variations in of gate length, channel thickness and doping, gate oxide parameters and source/drain doping were made in connection with numerical calculation of the device characteristics. Then a DG-MOSFET with a gate length of 15 nm was optimized. The optimized structure shows suppressed short channel behavior and short switching times of about 0.15 ps.
Design of Carbon Composite Driveshaft for Ultralight Aircraft Propulsion System
Authors: Poul R. , Růžička P. , Hanus . D. , Blahouš K.
Published: March 2021

This paper deals with the design of the carbon fibre composite driveshaft. This driveshaft will be used for connection between piston engine and propulsor of the type of axial-flow fan. Three different versions of driveshaft were designed and produced. Version 1 if completely made of Al alloy. Version 2 is of hybrid design where the central part is made of high strength carbon composite and flanges are made of Al alloy. Adhesive bond is used for connection between flanges and the central CFRP tube. Version 3 differs from the version 2 by aplication of ultrahigh-strength carbon fibre on the central part. Dimensions and design conditions are equal for all three versions to obtain simply comparable results. Calculations of driveshafts are described in the paper.
Embedded Coding of Astronomical Images
Authors: Elnagahy F. I. Y. , Haroon A. A. , Azzam Y. A. , Alawy A. El-Bassuny , Elminir H. K. , Šimák B.
Published: March 2021

Recursive partitioning of significant wavelet sub-bands (RPSWS) is an embedded rate scalable wavelet-based image coding algorithm. The RPSWS coder produces a fully embedded bit stream and encodes the image to exactly the desired bit rate (precise rate control). This paper investigates the applicability and the reliability of the RPSWS coder for coding astronomical images. Various types of astronomical images were compressed at different bit-rates using the RPSWS coder. The results were compared to the set partitioning in hierarchal trees coder (SPIHT), a well known embedded image corder. The comparison of the performance of the two algorithms was based on quantitative rate-distortion evaluations and subjective assessments of image quality.
Fuzzy Concepts in the Detection of Unexpected Situations
Authors: Bíla J. , Jura J.
Published: March 2021

This paper establishes three essential classes of unexpected situations (UX1, UX2, UX3), and concentrates attention on UX3 detection. Theconcepts of a special Model of System of Situations (MSS) and a Model of a System of Faults (MSF) are introduced. An original method isproposed for detecting unexpected situations indicating a violation of a proper invariant of MSS (MSF). The presented approach offers apromising application for starting and ending phases of complex processes, for knowledge discoveries on data and knowledge basesdeveloped with incomplete experience, and for modeling communication processes with unknown (disguised) communication subjects. Thepaper also presents a way to utilize ill-separable situations for UX3 detection. The paper deals with the conceptual background for detectingUX3 situations, recapitulates recent results in this field and opens the ways for further research.
Preparation of Thin Metal Layers on Polymers
Authors: Siegel J. , Kotál V.
Published: March 2021

Continuous gold layers of increasing thickness were prepared by the vacuum deposition method on pristine and plasma modified sheets of  PE, PET and PTFE. Various surface profiles were obtained. The surface morphology was studied using atomic force microscopy (AFM). The continuity of the metal layer on the polymer surface was validated by measuring its electrical resistance. Changes in the wettability of the plasma treated polymers were evaluated by measuring the aging curves. These were obtained as the dependence of contact angle on ageing time.
Flying Wings. A New Paradigm for Civil Aviation?
Authors: Martinez-Val R.
Published: March 2021

Over the last 50 years, commercial aviation has been mainly based what is currently called the conventional layout, characterized by a slender fuselage mated to a high aspect ratio wing, with aft-tail planes and pod-mounted engines under the wing. However, it seems that this primary configuration is approaching an asymptote in its productivity and performance characteristics. One of the most promising configurations for the future is the flying wing in its distinct arrangements: blended-wing-body, C-wing, tail-less aircraft, etc. These layouts might provide significant fuel savings and, hence, a decrease in pollution. This configuration would also reduce noise in take-off and landing. All this explains the great deal of activity carried out by the aircraft industry and by numerous investigators to perform feasibility and conceptual design studies of this aircraft layout to gain better knowledge of its main characteristics: productivity, airport compatibility, passenger acceptance, internal architecture, emergency evacuation, etc. The present paper discusses the main features of flying wings, their advantages over conventional competitors, and some key operational issues, such as evacuation and vortex wake intensity.
The Metric Operator and the Functional Integral Formulation of Pseudo-Hermitian Quantum Mechanics
Authors: Jones H. F.
Published: March 2021

Pseudo-Hermitian quantum theories are those in which the Hamiltonian H satisfies H† = ηHη-1, where η = e-Q is a positive-definite Hermitian operator, rather than the usual H† = H. In the operator formulation of such theories the standard Hilbert-space metric must be modified by the inclusion of η in order to ensure their probabilistic interpretation. With possible generalizations to quantum field theory in mind, it is important to ask how the functional integral formalism for pseudo-Hermitian theories differs from that of standard theories. It turns out that here Q plays quite a different role, serving primarily to implement a canonical transformation of the variables. It does not appear explicitly in the expression for the vacuum generating functional. Instead, the relation to the Hermitian theory is encoded via the dependence of Z on the external source j(t). These points are illustrated and amplified in various versions of the Swanson model, a non-Hermitian transform of the simple harmonic oscillator.
The Spherically Symmetric a2–dynamo and Some of its Spectral Peculiarities
Authors: Günther U. , Kirillov O. N. , Samsonov B. F. , Stefani F.
Published: March 2021

A brief overview is given of recent results on the spectral properties of spherically symmetric MHD α2-dynamos. In particular, the spectra of sphere-confined fluid or plasma configurations with physically realistic boundary conditions (BCs) (surrounding vacuum) and with idealized BCs (super-conducting surrounding) are discussed. The subjects comprise third-order branch points of the spectrum, self-adjointness of the dynamo operator in a Krein space as well as the resonant unfolding of diabolical points. It is sketched how certain classes of dynamos with a strongly localized α-profile embedded in a conducting surrounding can be mode decoupled by a diagonalization ofthe dynamo operator matrix. A mapping of the dynamo eigenvalue problem to that of a quantum mechanical Hamiltonian with energy dependent potential is used to obtain qualitative information about the spectral behavior. Links to supersymmetric Quantum Mechanics and to the Dirac equation are indicated.
Extended Supersymmetries in One Dimension
Authors: Toppan F.
Published: March 2021

This work covers part of the material presented at the Advanced Summer School in Prague. It is mostly devoted to the structural properties of Extended Supersymmetries in One Dimension. Several results are presented on the classification of linear, irreducible representations realized on a finite number of time-dependent fields. The connections between supersymmetry transformations, Clifford algebras and division algebras are discussed. A manifestly supersymmetric framework for constructing invariants without using the notion of superfields is presented. A few examples of one-dimensional, N-extended, off-shell invariant sigma models are computed. The relation between supersymmetry transformations and graph theory is outlined. The notion of the fusion algebra of irreps tensor products is presented. The relevance of one-dimensional Supersymmetric Quantum Mechanics as a way to extract information on higher dimensional supersymmetric field theories is discussed.
RealTimeFrame – A Real Time Processing Framework for Medical Video Sequences
Authors: Gross S. , Stehle T.
Published: March 2021

Imaging technology is highly important in today’s medical environments. It provides information upon which the accuracy of the diagnosis and consequently the wellbeing of the patient rely. Increasing the quality and significance of medical image data is therefore one the aims of scientific research and development. We introduce an integrated hardware and software framework for real time image processing in medical environments, which we call RealTimeFrame. Our project is designed to offer flexibility, easy expandability and high performance. We use standard personal computer hardware to run our multithreaded software. A frame grabber card is used to capture video signals from medical imaging systems. A modular, user-defined process chain performs arbitrary manipulations on the image data. The graphical user interface offers configuration options and displays the processed image in either window or full screen mode. Image source and processing routines are encapsulated in dynamic library modules for easy functionality extension without recompilation of the entire software framework. Documented template modules for sources and processing steps are part of the software’s source code.
Improved Evaluation of Planar Calibration Standards Using the TDR Preselection Method
Authors: Vancl J.
Published: March 2021

Calibration and correction methods for the Vector Network Analyzer (VNA) are based on the fundamental assumption of the constant error model, which is independent of connected calibration standards and/or devices under test (DUT). Unfortunately, this assumption is not satisfied well for planar calibration standards fabricated by etching technology on soft substrates. An evaluation of the error model is affected especially by variations in the manufacturing process and also by the reproducibility of an assembly. In this paper, we propose error minimization by selecting the best combination of available calibration standards based on time domain reflection (TDR) measurement, which can also be obtained by the fourier transformation from the measured S-parameters. The proposed method was verified experimentally using short, open, load and thru (SOLT) standards fabricated on an FR4 laminate substrate which achieves the essential reduction of the measurement error in the frequency range up to 15 GHz.