9 research outputs found
Spectral methods for circuit analysis
No full textThesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (p. 119-124).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Harmonic balance (HB) methods are frequency-domain algorithms used for high accuracy computation of the periodic steady-state of circuits. Matrix-implicit Krylov-subspace techniques have made it possible for these methods to simulate large circuits more efficiently. However, the harmonic balance methods are not so efficient in computing steady-state solutions of strongly nonlinear circuits with rapid transitions. While the time-domain shooting-Newton methods can handle these problems, the low-order integration methods typically used with shooting-Newton methods are inefficient when high solution accuracy is required. We first examine possible enhancements to the standard state-of-the-art preconditioned matrix-implicit Krylovsubspace HB method. We formulate the BDF time-domain preconditioners and show that they can be quite effective for strongly nonlinear circuits, speeding up the HB runtimes by several times compared to using the frequency-domain block-diagonal preconditioner. Also, an approximate Galerkin HB formulation is derived, yielding a small improvement in accuracy over the standard pseudospectral HB formulation, and about a factor of 1.5 runtime speedup in runs reaching identical solution error. Next, we introduce and develop the Time-Mapped Harmonic Balance method (TMHB) as a fast Krylov-subspace spectral method that overcomes the inefficiency of standard harmonic balance for circuits with rapid transitions. TMHB features a non-uniform grid and a time-map function to resolve the sharp features in the signals. At the core of the TMHB method is the notion of pseudo Fourier approximations. The rapid transitions in the solution waveforms are well approximated with pseudo Fourier interpolants, whose building blocks are complex exponential basis functions with smoothly varying frequencies. The TMHB features a matrix-implicit Krylov-subspace solution approach of same complexity as the standard harmonic balance method. As the TMHB solution is computed in a pseudo domain, we give a procedure for computing the real Fourier coefficients of the solution, and we also detail the construction of the time-map function. The convergence properties of TMHB are analyzed and demonstrated on analytic waveforms. The success of TMHB is critically dependent on the selection of a non-uniform grid. Two grid selection strategies, direct and iterative, are introduced and studied. Both strategies are a priori schemes, and are designed to obey accuracy and stability requirements. Practical issues associated with their use are also addressed. Results of applying the TMHB method on several circuit examples demonstrate that the TMHB method achieves up to five orders of magnitude improvement in accuracy compared to the standard harmonic balance method. The solution error in TMHB decays exponentially faster than the standard HB method when the size of the Fourier basis increases linearly. The TMHB method is also up to six times faster than the standard harmonic balance method in reaching identical solution accuracy, and uses up to five times less computer memory. The TMHB runtime speedup factor and storage savings favorably increase for stricter accuracy requirements, making TMHB well suited for high accuracy simulations of large strongly nonlinear circuits with rapid transitions.by Ognen J. Nastov.Ph.D
Advances of Polymerase Chain Reaction Sperm Testing in Men With Chronic Prostatitis and Pelvic Pain Syndrome
No full textProstate inflammation is a common condition in men characterized by swelling of the prostate gland, often associated with other prostate diseases. Understanding the role of chronic inflammation in prostatic diseases is important due to the changes in prostatic cells and the persistence when undiagnosed. The evaluation and management of chronic prostatitis (CP) and chronic pelvic pain (CPP) involve specific diagnostic tests. This study aimed to evaluate the efficiency of the polymerase chain reaction (PCR) detection kits that use multiplex real-time PCR in comparison to standard microbiology sperm culture for detecting pathogens in individuals with CP and CPP. This retrospective observational study analyzed data from a database of 68 patients, aged 50.1 ± 17.8 years and treated at a secondary care urology center. PCR testing detected at least one microorganism in 63/68 samples (92.6%), while conventional culture yielded positive results in 12/68 cases (17.6%). The most detected microorganisms by PCR were the Bacteroides/Porphyromonas/Prevotella group (61.8%). Most of the samples were found to be polymicrobial, with the most common high-order combination consisting of Anaerococcus spp., Atopobium cluster, Bacteroides/Porphyromonas/Prevotella, Megasphaera/Veillonella/Dialister, and Peptostreptococcus/Parvimonas. This study concluded that PCR is more effective than traditional sperm culture in detecting organisms (p < .05), especially in identifying polymicrobial infections and fastidious microorganisms in patients with CP and CPP. PCR has higher sensitivity in detecting pathogens, including those often missed by standard culture techniques, leading to improved clinical outcomes, particularly in cases of polymicrobial infection
Cellulose dissolution: Comparison of two non-derivatizing solvent systems and the effect of additives
No full textTitle: Cellulose dissolution: Comparison of two non-derivatizing solvent systems and the effect of additives Author: Nikolay Kotov Institute: Institute of Macromolecular Chemistry, Czech Academy of Sciences Supervisor of the doctoral thesis: RNDr. Jiří Dybal, CSc. Consultant: Mgr. Adriana Šturcová, Ph.D. Institute of Macromolecular Chemistry, Czech Academy of Sciences, Department of Vibrational Spectroscopy Abstract: Cellulose is an abundant renewable material, which processing and applicability is limited owing to cellulose inability to dissolve in commonly used solvents. Only specific solvents or their combinations are able to dissolve cellulose and its dissolution processes remain unclear till nowadays. Aim of this thesis was to acquire new experimental information on the changes which cellulose exhibits upon dissolution in two exemplary solvents: an ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl) and in an organic solvent N,N-dimethylacetamide (DMAc) with lithium chloride (LiCl). The main tool for that investigation is vibrational spectroscopy which provides valuable information about the polymer structure. Similarities and differences found in the spectra of cellulose in those two solvents and influence of cellulose on the solvents are analyzed. Furthermore, influence of additives on the..
Alteration of the redox signalling in liver cancer cells by non-thermal plasma and laser irradiation
No full textTitle: Alteration of the redox signalling in liver cancer cells by non-thermal plasma and laser irradiation Author: Mgr. Barbora Smolková Department: Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences Supervisor: Mgr. Oleg Lunov, PhD., Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences Abstract: Over the years, the implementation of physics-based techniques into medicine have contributed to the development of novel approaches for diagnostics and treatment. Recently, new promising therapeutic approaches, namely non-thermal plasma and low-power light (laser) therapy have gained attention for the treatment of various diseases. This dissertation thesis aims to critically assess the current knowledge in the field of plasma medicine and laser irradiation. In particular, it focuses on the interaction and molecular mechanisms of non-thermal plasma and laser light irradiation in 3 different hepatic cancer cell lines. We hope that our critical analysis will help researchers to overcome challenges and develop in the future better controlled, safer, and more robust NTP- and laser-based treatment modalities. Keywords: hepatic cancer cells, non-thermal plasma, laser irradiation, oxidative stress, redox signallin
Změna redoxní signalizace v buňkách rakoviny jater působením nízkoteplotního plazmatu a laserového ozařování
No full textTitle: Alteration of the redox signalling in liver cancer cells by non-thermal plasma and laser irradiation Author: Mgr. Barbora Smolková Department: Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences Supervisor: Mgr. Oleg Lunov, PhD., Department of Optical and Biophysical Systems, Institute of Physics of the Czech Academy of Sciences Abstract: Over the years, the implementation of physics-based techniques into medicine have contributed to the development of novel approaches for diagnostics and treatment. Recently, new promising therapeutic approaches, namely non-thermal plasma and low-power light (laser) therapy have gained attention for the treatment of various diseases. This dissertation thesis aims to critically assess the current knowledge in the field of plasma medicine and laser irradiation. In particular, it focuses on the interaction and molecular mechanisms of non-thermal plasma and laser light irradiation in 3 different hepatic cancer cell lines. We hope that our critical analysis will help researchers to overcome challenges and develop in the future better controlled, safer, and more robust NTP- and laser-based treatment modalities. Keywords: hepatic cancer cells, non-thermal plasma, laser irradiation, oxidative stress, redox signallingNázev práce: Změna redoxní signalizace v buňkách rakoviny jater působením nízkoteplotního plazmatu a laserového ozařování Autor: Mgr. Barbora Smolková Katedra: Oddělení optických a biofyzikálních systémů, Fyzikální ústav AV ČR Školitel: Mgr. Oleg Lunov, PhD., Oddělení optických a biofyzikálních systémů, Fyzikální ústav AV ČR Abstrakt: Aplikace fyzikálních metod jsou dlouhá léta významným prostředkem pro vývoj inovativních diagnostických a léčebných procesů v medicíně. V poslední době si pro svůj léčebný potenciál a vlastnosti získaly pozornost nízkoteplotní plazma a lasery o nízkém výkonu. Tato disertační práce shrnuje dosud známé informace v oblasti výzkumu nízkoteplotního plazmatu a laserové terapie. Práce se zaměřuje zejména na studium molekulárních mechanismů a efektů vzájemného působení nízkoteplotního plazmatu a laserového ozařování u tří buněčných linií rakovinných buněk jater člověka. Věříme, že analýza, kterou tato disertační práce představuje, bude přínosem pro budoucí výzkum a vývoj lépe ovladatelných a spolehlivých léčebných využití nízkoteplotního plazmatu a laserů o nízkém výkonu. Klíčová slova: Buněčné linie rakoviny hepatocytů, nízkoteplotní plazma, laserové ozařování, oxidační stres, redoxní signalizaceFaculty of Mathematics and PhysicsMatematicko-fyzikální fakult
Porovnání dvou nederivatizujících solventních systémů a vliv aditiv
No full textNázev práce: Rozpouštění celulózy: Porovnání dvou nederivatizujících solventních systémů a vliv aditiv Autor: Nikolay Kotov Ústav: Ústav makromolekulární chemie, Akademie věd České republiky, v. v. i. Vedoucí disertační práce: RNDr. Jiří Dybal, CSc. Konzultant: Mgr. Adriana Šturcová, Ph.D. Ústav makromolekulární chemie, Akademie věd České republiky, v. v. i., Odděleni vibrační spektroskopii Abstrakt: Celulóza je snadno dostupný a hojně využívaný materiál získávaný z obnovitelných zdrojů. Při jejím zpracování je limitující její omezená rozpustnost. Rozpouští se pouze ve specifických rozpouštědlech či jejich kombinacích a porozumění procesům rozpouštění není uspokojivé. Cílem této dizertační práce je získání nových experimentálních informací o změnách struktury celulózy při jejím rozpouštění ve dvou rozpouštědlech: v 1-butyl-3-methylimidazoliumchloridu (bmimCl), tj. iontové kapalině, a v N,N-dimethylacetamidu (DMAc) s přídavkem chloridu lithného (LiCl), tj. organickém rozpouštědle s anorganickou solí. Hlavním nástrojem studia jsou metody vibrační spektroskopie, které poskytují cenné informace o struktuře polymerů. Podobnosti a rozdíly nalezené ve spektrech celulózy v bmimCl a v DMAc s přídavkem LiCl jsou systematicky analyzovány a studován je též vliv celulózy na rozpouštědla. Pozornost je věnována vlivu...Title: Cellulose dissolution: Comparison of two non-derivatizing solvent systems and the effect of additives Author: Nikolay Kotov Institute: Institute of Macromolecular Chemistry, Czech Academy of Sciences Supervisor of the doctoral thesis: RNDr. Jiří Dybal, CSc. Consultant: Mgr. Adriana Šturcová, Ph.D. Institute of Macromolecular Chemistry, Czech Academy of Sciences, Department of Vibrational Spectroscopy Abstract: Cellulose is an abundant renewable material, which processing and applicability is limited owing to cellulose inability to dissolve in commonly used solvents. Only specific solvents or their combinations are able to dissolve cellulose and its dissolution processes remain unclear till nowadays. Aim of this thesis was to acquire new experimental information on the changes which cellulose exhibits upon dissolution in two exemplary solvents: an ionic liquid 1-butyl-3-methylimidazolium chloride (bmimCl) and in an organic solvent N,N-dimethylacetamide (DMAc) with lithium chloride (LiCl). The main tool for that investigation is vibrational spectroscopy which provides valuable information about the polymer structure. Similarities and differences found in the spectra of cellulose in those two solvents and influence of cellulose on the solvents are analyzed. Furthermore, influence of additives on the...Matematicko-fyzikální fakultaFaculty of Mathematics and Physic
Mapping Policies and Practices for the Preparation of Teachers for Inclusive Education in Contexts of Social and Cultural Diversity. Former Yugoslav Republic of Macedonia Country Report
No full textThis report is one of seven being prepared in the context of a regional study entitled Mapping Policies and Practices for the Preparation of Teachers for Inclusive Education in Contexts of Social and Cultural Diversity, which was commissioned by the European Training Foundation (ETF) and is being conducted by SCIENTER and the Centre for Education Policy. It focuses on policies and practices for the preparation of teachers for inclusive education in the Former Yugoslav Republic of Macedonioa, with particular focus on pre-service education and in-service professional development. This is a qualitative study exploring the perceptions of the relevant actors through document analysis, interviews and focus groups, and, to a lesser extent, qualitative information collected in an online survey. (DIPF/author
3D City Models and urban information: current issues and perspectives
No full textConsidering sustainable development of cities implies investigating cities in a holistic way taking into account many interrelations between various urban or environmental issues. 3D city models are increasingly used in different cities and countries for an intended wide range of applications beyond mere visualization. Could these 3D City models be used to integrate urban and environmental knowledge? How could they be improved to fulfill such role? We believe that enriching the semantics of current 3D city models, would extend their functionality and usability; therefore, they could serve as integration platforms of the knowledge related to urban and environmental issues allowing a huge and significant improvement of city sustainable management and development. But which elements need to be added to 3D city models? What are the most efficient ways to realize such improvement / enrichment? How to evaluate the usability of these improved 3D city models?
These were the questions tackled by the COST Action TU0801” Semantic enrichment of 3D city models for sustainable urban development”. This book gathers various materials developed all along the four year of the Action and the significant breakthroughs.COST TU0801 Semantic Enrichment of 3d city models for sustainable urban developmen
The International Climate Psychology Collaboration: Climate change-related data collected from 63 countries
No full textClimate change is currently one of humanity's greatest threats. To help scholars understand the psychology of climate change, we conducted an online quasi-experimental survey on 59,508 participants from 63 countries (collected between July 2022 and July 2023). In a between-subjects design, we tested 11 interventions designed to promote climate change mitigation across four outcomes: climate change belief, support for climate policies, willingness to share information on social media, and performance on an effortful pro-environmental behavioural task. Participants also reported their demographic information (e.g., age, gender) and several other independent variables (e.g., political orientation, perceptions about the scientific consensus). In the no-intervention control group, we also measured important additional variables, such as environmentalist identity and trust in climate science. We report the collaboration procedure, study design, raw and cleaned data, all survey materials, relevant analysis scripts, and data visualisations. This dataset can be used to further the understanding of psychological, demographic, and national-level factors related to individual-level climate action and how these differ across countries. © 2024. The Author(s).</p
