Search results for " rando"
showing 10 items of 498 documents
Arc crossing minimization in graphs with GRASP
2001
Graphs are commonly used to represent information in many fields of science and engineering. Automatic drawing tools generate comprehensible graphs from data, taking into account a variety of properties, enabling users to see important relationships in the data. The goal of limiting the number of arc crossings is a well-admitted criterion for a good drawing. In this paper, we present a Greedy Randomized Adaptive Search Procedure (GRASP) for the problem of minimizing arc crossings in graphs. Computational experiments with 200 graphs with up to 350 vertices are presented to assess the merit of the method. We show that simple heuristics are very fast but result in inferior solutions, while hig…
Conjugate Gradient Method for Brain Magnetic Resonance Images Segmentation
2018
Part 8: Pattern Recognition and Image Processing; International audience; Image segmentation is the process of partitioning the image into regions of interest in order to provide a meaningful representation of information. Nowadays, segmentation has become a necessity in many practical medical imaging methods as locating tumors and diseases. Hidden Markov Random Field model is one of several techniques used in image segmentation. It provides an elegant way to model the segmentation process. This modeling leads to the minimization of an objective function. Conjugate Gradient algorithm (CG) is one of the best known optimization techniques. This paper proposes the use of the nonlinear Conjugat…
MASked-unconTrolled hypERtension management based on office BP or on ambulatory blood pressure measurement (MASTER) Study: a randomised controlled tr…
2018
Introduction Masked uncontrolled hypertension (MUCH) carries an increased risk of cardiovascular (CV) complications and can be identified through combined use of office (O) and ambulatory (A) blood pressure (BP) monitoring (M) in treated patients. However, it is still debated whether the information carried by ABPM should be considered for MUCH management. Aim of the MASked-unconTrolled hypERtension management based on OBP or on ambulatory blood pressure measurement (MASTER) Study is to assess the impact on outcome of MUCH management based on OBPM or ABPM. Methods and analysis MASTER is a 4-year prospective, randomised, open-label, blinded-endpoint investigation. A total of 1240 treated hyp…
Modeling of Hardy-Weinberg Equilibrium Using Dynamic Random Networks in an ABM Framework
2023
Hardy-Weinberg equilibrium is the fundamental principle of population genetics. In this article, we present a new NetLogo model called “Hardy-Weinberg Basic model v 2.0”, characterized by a strict adherence to the original assumptions made by Hardy and Weinberg in 1908. A particularly significant feature of this model is that the algorithm does not make use of the binomial expansion formula. Instead, we show that using a procedure based on dynamic random networks, diploid equilibrium can be achieved spontaneously by a population of agents reproducing sexually in a Mendelian fashion. The model can be used to conduct simulations with a wide range of initial population sizes and genotype distr…
Helicobacter pylori - diagnostika izmantojot 13C urīnvielas elptestu un seroloģijas testu: rezultātu salīdzināšana
2017
Ievads. 2012.gada veiktajā pētījumā tika iegūti dati, ka Latvijā Helicobacter Pylori (HP) izplatība pieaugušo populācijā ir augstā līmenī – 79.21%. Prezentētajā pētījumā tika analizēta HP infekcijas izplatība saistībā ar sociāli-demogrāfiskiem faktoriem - dalībnieku izglītības līmeni, nodarbinātību, vidējiem ienākumiem, ģimenes stāvokli, smēķēšanas paradumiem Latvijas iedzīvotājiem. Pētījuma mērķis. HP testu, kuri veikti izmantojot 13C urīnvielas elptestu un seroloģijas testu Daudzcentru randomizēts pētījums kuņģa vēža izraisītās mirstības samazināšanai (GISTAR) pētījuma ietvarā, rezultātu salīdzināšana saistībā ar sociāli-demogrāfiskiem faktoriem. Materiāli un metodes. Darbs ir šķērsgriezu…
Imaging-guided interventions modulating portal venous flow: Evidence and controversies
2021
Portal hypertension is defined by an increase in the portosystemic venous gradient. In most cases, increased resistance to portal blood flow is the initial cause of elevated portal pressure. More than 90% of cases of portal hypertension are estimated to be due to advanced chronic liver disease or cirrhosis. Transjugular intrahepatic portosystemic shunts, a non-pharmacological treatment for portal hypertension, involve the placement of a stent between the portal vein and the hepatic vein or inferior vena cava which helps bypass hepatic resistance. Portal hypertension may also be a result of extrahepatic portal vein thrombosis or compression. In these cases, percutaneous portal vein recanalis…
Avoiding Boundary Effects in Wang-Landau Sampling
2003
A simple modification of the ``Wang-Landau sampling'' algorithm removes the systematic error that occurs at the boundary of the range of energy over which the random walk takes place in the original algorithm.
The Schur Expansion of Characteristic Polynomials and Random Matrices
2021
We develop a new framework to compute the exact correlators of characteristic polynomials, and their inverses, in random matrix theory. Our results hold for general potentials and incorporate the effects of an external source. In matrix model realizations of string theory, these correspond to correlation functions of exponentiated "(anti-)branes" in a given background of "momentum branes". Our method relies on expanding the (inverse) determinants in terms of Schur polynomials, then re-summing their expectation values over the allowed representations of the symmetric group. Beyond unifying previous, seemingly disparate calculations, this powerful technique immediately delivers two new result…
Path integral solution by fractional calculus
2008
In this paper, the Path Integral solution is developed in terms of complex moments. The method is applied to nonlinear systems excited by normal white noise. Crucial point of the proposed procedure is the representation of the probability density of a random variable in terms of complex moments, recently proposed by the first two authors. Advantage of this procedure is that complex moments do not exhibit hierarchy. Extension of the proposed method to the study of multi degree of freedom systems is also discussed.
Cultural adaptation of the Smiling is Fun program for the treatment of depression in the Ecuadorian public health care system: A study protocol for a…
2021
Background Depression is one of the world's major health problems. Due to its high prevalence, it constitutes the first cause of disability among the Americas, where only a very low percentage of the population receives the adequate evidence-based psychological treatment. Internet-Based Interventions (IBIs) are a great alternative to reduce the treatment gap for mental disorders. Although there are several studies in low-and middle-income countries proving IBIs' feasibility and acceptability, there is still little evidence of the effectiveness in diverse social and cultural contexts such as Latin America. Methods Two studies will be described: Study 1 is focused on the cultural adaptation o…