144 research outputs found
Limitations of the classical phase-locked loop analysis
Nonlinear analysis of the classical phase-locked loop (PLL) is a challenging
task. In classical engineering literature simplified mathematical models and
simulation are widely used for its study. In this work the limitations of
classical engineering phase-locked loop analysis are demonstrated, e.g., hidden
oscillations, which can not be found by simulation, are discussed. It is shown
that the use of simplified dynamical models and the application of simulation
may lead to wrong conclusions concerning the operability of PLL-based circuits
Coupling BM3D with directional wavelet packets for image denoising
The paper presents an image denoising algorithm by combining a method that is
based on directional quasi-analytic wavelet packets (qWPs) with the popular
BM3D algorithm. The qWPs and its corresponding transforms are designed in [1].
The denoising algorithm qWP (qWPdn) applies an adaptive localized soft
thresholding to the transform coefficients using the Bivariate Shrinkage
methodology. The combined method consists of several iterations of qWPdn and
BM3D algorithms, where the output from one algorithm updates the input to the
other (cross-boosting).The qWPdn and BM3D methods complement each other. The
qWPdn capabilities to capture edges and fine texture patterns are coupled with
utilizing the sparsity in real images and self-similarity of patches in the
image that is inherent in the BM3D. The obtained results are quite competitive
with the best state-of-the-art algorithms. We compare the performance of the
combined methodology with the performances of cptTP-CTF6, DAS-2 algorithms,
which use directional frames, and the BM3D algorithm. In the overwhelming
majority of the experiments, the combined algorithm outperformed the above
methods.Comment: 26 pages. arXiv admin note: substantial text overlap with
arXiv:2001.04899, arXiv:1907.01479; text overlap with arXiv:2008.0536
Approximating optimal control problems governed by variational inequalities
It is proposed an approximating method for optimal control problems governed by elliptic variational inequalities. Some applications and numerical examples are treated
Safety of Novel Amino-5-laevulinate Photosensitizer Precursors in Photodynamic Therapy on Healthy Human Skin
Peer reviewe
Value priorities and their relations with quality of life in the Baby Boomer generation of Lithuanian nurses: a cross-sectional survey
<p>Abstract</p> <p>Background</p> <p>The understanding of the values of nurses is especially important, since nurses constitute 80% of workforce in the healthcare system in Lithuania. In addition to that, nursing is one of the major constituents of healthcare. The aim of this study was to determine what values predominate in the cohort of Baby Boomer nurses, and to evaluate the relation of these values with quality of life using M. Rokeach's terminal and instrumental values scale. M.Rokeach distinguished terminal values (such as world peace, wisdom, and happiness), which are preferred end-states of existence, and instrumental values (such as responsibility and cooperation), which are preferred modes of conduct.</p> <p>Methods</p> <p>We performed a representative anonymous questionnaire-based inquiry of nurses working in regional hospitals of Lithuania. The nurses who participated in the study were distributed into four work cohorts: the Veterans, the Baby Boomers, the Generation Xers, and the Generation Nexters. The majority of the nurses belonged to the Baby Boomers and the Generation Xers cohorts. Since in Lithuania, like in the whole Europe, the representatives of the Baby Boomers generation are predominating among working people, we selected this cohort (N = 387) for the analysis. The survey data was processed using the SPSS statistical software package</p> <p>Results</p> <p>The main values in life were family security, tranquility, and a sense of accomplishment. However, such values as true friendship, equality, and pleasurable and leisured life were seen as rather insignificant. The most important instrumental values were honesty, skillfulness, and responsibility. Our study showed a statistically significant (albeit weak) correlation between the QOL and terminal values such as the sense of accomplishment, tranquility, equality, and pleasure, as well as the instrumental value – obedience. We detected a statistically significant relationship between good QOL and satisfaction with oneself, relationships with the surrounding people, and friends' support.</p> <p>Conclusion</p> <p>The findings of our study showed that, although Lithuania was under a totalitarian regime for 50 years, both the terminal and the instrumental values of the Baby Boomers generation are very similar to those of the same generation in other countries.</p
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