1,125 research outputs found
A Descent Method for Equality and Inequality Constrained Multiobjective Optimization Problems
In this article we propose a descent method for equality and inequality
constrained multiobjective optimization problems (MOPs) which generalizes the
steepest descent method for unconstrained MOPs by Fliege and Svaiter to
constrained problems by using two active set strategies. Under some regularity
assumptions on the problem, we show that accumulation points of our descent
method satisfy a necessary condition for local Pareto optimality. Finally, we
show the typical behavior of our method in a numerical example
A new adaptive algorithm for convex quadratic multicriteria optimization
We present a new adaptive algorithm for convex quadratic multicriteria optimization. The algorithm is able to adaptively refine the approximation to the set of efficient points by way of a warm-start interior-point scalarization approach. Numerical results show that this technique is faster than a standard method used for this problem
Coarse-graining Approaches in Univariate Multiscale Sample and Dispersion Entropy
The evaluation of complexity in univariate signals has attracted considerable attention in recent years. This is often done using the framework of Multiscale Entropy, which entails two basic steps: coarse-graining to consider multiple temporal scales, and evaluation of irregularity for each of those scales with entropy estimators. Recent developments in the field have proposed modifications to this approach to facilitate the analysis of short-time series. However, the role of the downsampling in the classical coarse-graining process and its relationships with alternative filtering techniques has not been systematically explored yet. Here, we assess the impact of coarse-graining in multiscale entropy estimations based on both Sample Entropy and Dispersion Entropy. We compare the classical moving average approach with low-pass Butterworth filtering, both with and without downsampling, and empirical mode decomposition in Intrinsic Multiscale Entropy, in selected synthetic data and two real physiological datasets. The results show that when the sampling frequency is low or high, downsampling respectively decreases or increases the entropy values. Our results suggest that, when dealing with long signals and relatively low levels of noise, the refine composite method makes little difference in the quality of the entropy estimation at the expense of considerable additional computational cost. It is also found that downsampling within the coarse-graining procedure may not be required to quantify the complexity of signals, especially for short ones. Overall, we expect these results to contribute to the ongoing discussion about the development of stable, fast and robust-to-noise multiscale entropy techniques suited for either short or long recordings
A Method for Constrained Multiobjective Optimization Based on SQP Techniques
We propose a method for constrained and unconstrained nonlinear multiobjective optimization problems that is based on an SQP-type approach. The proposed algorithm maintains a list of nondominated points that is improved both for spread along the Pareto front and optimality by solving single-objective constrained optimization problems. These single-objective problems are derived as SQP problems based on the given nondominated points.Under appropriate differentiability assumptions we discuss convergence to local optimal Pareto points. We provide numerical results for a set of unconstrained and constrained multiobjective optimization problems in the form of performance and data profiles, where several performance metrics are used. The numerical results confirm the superiority of the proposed algorithm against a state-of-the-art multiobjective solver and a classical scalarization approach, both in the quality of the approximated Pareto front and in the computational effort necessary to compute the approximation.<br/
A Comparative Study
Background: The Narcissism Inventory (NI) is a frequently used German
inventory for measuring narcissism in clinical settings; an additional short
version (NI-90) also exists. Psychometric properties of the NI-90 scales were
examined in clinical and non-clinical adolescent samples. Methods: Two
adolescent samples were assessed with the NI-90: a non-clinical sample (n =
439, mean age ± SD = 15.05 ± 1.77 years) and a clinical sample (n = 235, 18.26
± 0.77 years). Confirmatory factor analysis and principle component analysis
were used to scrutinize the structure of the scales. Multiple regression
analysis was used to predict the scores on two scales (helpless self; negative
body self). Results: This study revealed heterogeneity in the NI-90 scales,
which in turn explains the wide range seen in Cronbach’s α (from 0.53 to
0.93). The postulated 4-factor structure could not be replicated in both
samples. Multiple regression analysis revealed that personality disorder did
not significantly predict negative body self or helpless self scores, whereas
eating, mood, as well as somatoform and conversion disorders did. One NI-90
scale (greedy for praise and reassurance) showed sufficient psychometric
quality for the measurement of narcissism in both samples. Conclusion: Based
on the results, the authors recommend revising the NI-90. Items that may be
useful for measuring aspects related to affective and body image complaints
are presented. The greedy for praise and reassurance scale may be valuable for
measuring features of ‘overt’ narcissism
Guest Editorial: Special Issue On Multirate Systems, Filter Banks, Wavelets, And Applications
The last decade has seen a tremendous amount of
activity and emergence of applications in the areas of
filter banks and wavelets. These topics are of such wide
interest that there have been papers in many different journals, conferences, and workshops in diverse disciplines. However, many aspects of the theory, design, and application of filter banks and wavelets are of great interest to the circuits and systems community as well. Our editorial team felt that this was a perfect time to put together a special issue with state-of-the-art papers on these popular topics. All of the papers have been peer-reviewed according to the usual practice of
this TRANSACTIONS. Almost in parallel, there is also a similar
special issue (April 1998) by the IEEE TRANSACTIONS ON SIGNAL
PROCESSING, with a slightly greater emphasis on applications.
Many well-known authors have contributed articles to these
special issues and we expect these to serve as valuable
references for a long time to come
Precise dipole moment and quadrupole coupling constants of benzonitrile
We have performed Fourier transform microwave spectroscopy of benzonitrile,
without and with applied electric fields. From the field-free
hyperfine-resolved microwave transitions we simultaneously derive accurate
values for the rotational constants, centrifugal distortion constants, and
nitrogen nuclear quadrupole coupling constants of benzonitrile. By measuring
the Stark shift of selected hyperfine transitions the electric dipole moment of
benzonitrile is determined to D.Comment: 6 pages, 2 tables (elsart
Conversion of the Mycotoxin Patulin to the Less Toxic Desoxypatulinic Acid by the Biocontrol Yeast Rhodosporidium kratochvilovae Strain LS11
Se describe en este artículo el descubrimiento de la degradación de la micotoxina patulina por una levaduraThe infection of stored apples by the fungus Penicillium expansum causes the contamination of fruits and fruit-derived
products with the mycotoxin patulin, which is a major issue in food safety. Fungal attack can be prevented by beneficial
microorganisms, so-called biocontrol agents. Previous time-course thin layer chromatography analyses showed that the aerobic
incubation of patulin with the biocontrol yeast Rhodosporidium kratochvilovae strain LS11 leads to the disappearance of the
mycotoxin spot and the parallel emergence of two new spots, one of which disappears over time. In this work, we analyzed the
biodegradation of patulin effected by LS11 through HPLC. The more stable of the two compounds was purified and characterized by
nuclear magnetic resonance as desoxypatulinic acid, whose formation was also quantitated in patulin degradation experiments. After
R. kratochvilovae LS11 had been incubated in the presence of 13C-labeled patulin, label was traced to desoxypatulinic acid, thus
proving that this compound derives from the metabolization of patulin by the yeast. Desoxypatulinic acid was much less toxic than
patulin to human lymphocytes and, in contrast to patulin, did not react in vitro with the thiol-bearing tripeptide glutathione. The
lower toxicity of desoxypatulinic acid is proposed to be a consequence of the hydrolysis of the lactone ring and the loss of functional
groups that react with thiol groups. The formation of desoxypatulinic acid from patulin represents a novel biodegradation pathway
that is also a detoxification process
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