Problems of Corneal Endothelial Image Binarization

In this paper we present two methods of binarization of corneal endothelial images. The binarization is a first step of advanced image analysis. Images of corneal endothelial obtained by the specular microscopy have a poor dynamic range and they are usually non-uniformly illuminated. The binarization endothelial images is not trivial. Two binarization algorithms are proposed. The output images are presented. The quality of algorithms is discussed

Optimal selection of numerical models for flood embankment pore pressure and temperature data

The aim of the ISMOP project is to study processes in earthen flood embankments: water filtration, pore pressure changes, and temperature changes due to varying water levels in the riverbed. Developing a system for continuous monitoring of flood embankment stability is the main goal of this project. A full-size earthen flood embankment with built-in sensors was built in Czernichow and used to conduct experiments involving the simulation of different flood waves, with parameters mostly measured at time intervals of 15 minutes. Numerical modelling—in addition to providing information about phenomena occurring in the embankment due to external factors and changes in water level—could be used to assess the state of the embankment. Modelling was performed using Itasca Flac 2D 7.0 with an assumed grid cell size of 10x10 cm. The water level in the embankment simulated the water flow in the Wisła River and the temperature of the air and water. Data about the state of the flood embankment was exported every hour.Using numerical models and real experiment data, a model-driven module was used to perform comparisons. Analyses of each half-section of the flood embankment were carried out separately using similarity measures and an aggregate window.For the tests, the North-West (NW) half cross-section of the embankment was chosen, which contains pore pressure and temperature sensors UT6 to UT10. The water level in the embankment was raised to a height of 3m; the best numerical model was considered the one that best matched the actual data recorded by the sensors during the experiment. The experiment period was from 9pm on 29/08/2016 to 9am on 03/09/2016.Seventeen numerical models of the water level rising to 2, 3, and 4 meters were compared against real experimental data from the NW half cross-section. The first step was to verify the similarity between the incoming data from the sensors. If the correlation value exceeded 0.8, the data from the sensors was averaged. The experimental data was then compared against the numerical models using least absolute deviations L1-Norm. The L1-Norm varied from 26 to 32, depending on window length and the numerical model used

Analysis of body dynamics moving in a rotating system : detailed derivation of Coriolis force

Wstęp i cele: W artykule wyprowadzone zostały równania, które pozwalają przeliczyć położenie, prędkość oraz przyśpieszenie ciała punktowego mierzone w układzie obrotowym do położenia, prędkości oraz przyśpieszenia mierzonego w układzie inercjalnym. Materiał i metody: W pracy zastosowano metodę dedukcji matematycznej. Wyniki: Równanie otrzymane dla przyśpieszenia posiada trzy składowe, z których jedna to siła dośrodkowa, natomiast druga to siła Coriolisa. Przedstawiona została także dyskusja na temat wyprowadzonego równania. Wniosek: W artykule został przedstawiony precyzyjniejszy zapis wzoru na prędkość oraz przyśpieszenie w układzie inercjalnym niż obecnie stosowane. Pokazane zostało na przykładzie, że przyśpieszenie Coriolisa nie jest niezależne od przyśpieszenia dośrodkowego. W rozważanym przykładzie te dwa przyśpieszenie przeciwdziałały sobie nawzajem.Introduction and aim: The article derives equations that allow the conversion of the position, velocity and acceleration of a point body measured in a rotational system to the position, velocity and acceleration measured in an inertial system. Material and methods: Mathematical deduction method has been used in the paper. Results: The equation obtained for acceleration has three components, one of which is centripetal force, while the other is Coriolis force. A discussion on the derived equation was also presented. Conclusion: The article presents a more precise record of the formula for speed and acceleration in an inertial system. It is shown on the example that Coriolis acceleration is not independent of centripetal acceleration. In the example under consideration these two accelerations counteracted each other

Cellular automata for seismic travel time estimation abstract /

Tyt. z nagłówka.Bibliogr. s. 542.In this work, the application of the cellular automata for the seismic first breaks time estimation is presented. Cellular automata (CA) algorithms are usually described by set of simple rules applied onto the grid of cells, which can represent one of the few different discrete states. In spite of this simplicity, these algorithms can still simulate variety of complex physical processes, i.e. model the fluids or gases behavior, but also simulate and predict forests fire or the spread of diseases (Turcotte 1997). What is more, these algorithms are easy to accelerate using one of the most advanced parallelization techniques, like graphics card programming - the calculation can be then performed even 1000 times faster. In this work one of the popular CA, presented by Hardy et al. (1973), was modified, according to Rothman (1987), to perform the simulation of the seismic wave propagation in geological medium. This CA was initially designed to simulate gas behavior in a reservoir, but it was modified in the following way: each cell of the grid contains set of values, which represents particles - positive and negative - that describes expansion and compression, respectively, of that cell. Then, both particle sets are calculated separately in two steps: the first is the propagation, when each particle is moved to next cell according to its movement; the second is collision, when rules are applied on each particle, if there is more than one particle in the cell. The collision rules can be divided into categories that represent their complexity, i.e. more complex behavior can be achieved if static particles are implemented, but this requires additional rules of collisions with moving particles. All the rules have to preserve the principle of conservation of mass and momentum. The major modification of the algorithm described by Rothman (1987) is the implementation of the Boltzmann lattice method (Huang 2007), which changes the regular rectangular cellular grid for the triangular network. This modification provides more option when implementing algorithm, especially the collisions rules. On the one hand, triangular grid requires slightly different approach to represent it in computer memory, just like the implementations of the rules. On the other hand, triangular grid can produce better simulation results compared to the classical rectangular grid. The results of this simulation can be used in further calculations, i.e. to solve the inverse problem. To make this CA useful, it has to provide either better than similar methods errorless results or significantly shorter computation time with comparable errors. In this work the CA is compared with mathematical wave propagation solution and the Shortest Path Method (SPM). SPM uses graph theory to reconstruct seismic ray trajectory in a real, geological medium. This method was first described in Moser (1991). As it is more time-consuming than linear method, for large model the parallel approach is necessary (Pieta et al. 2013). One of the major advantages is the possibility of optimization of the modeling quality and calculation time by adjusting number of accessory nodes. This method is easily extendable to cover the anisotropy case. This work describes, verifies and validates the CA algorithms to checks the potential of use in further calculations for solving the forward problem in seismic modeling. The research shows that the presented CA method, in spite of its speed and parallelization options, can not be applied if high precision is required.Dostępny również w formie drukowanej.KEYWORDS: CA algorithm, Shortest Path Method, SPM

Możliwości akceleracji przestrzennych baz danych na podstawie procesorów kart graficznych oraz funkcji użytkownika

This paper proves that it is possible to accelerate spatial data analysis, for example astronomic data, without modifying source code of the database engine. User-defined function (UDF) were used in cooperation with NVIDIA CUDA to increase efficiency and speed of numerical operations.W artykule wykazano, iż możliwe jest przyspieszenie procesów analizy danych przestrzennych, w tym wypadku danych katalogu astrometrycznego gwiazd, bez konieczności modyfikacji kodu źródłowego bazy danych. Wykorzystano do tego celu zewnętrzne funkcje użytkownika UDF oraz technologię CUDA firmy NVIDIA, która pozwala na skuteczną akcelerację obliczeń numerycznych na podstawie procesorów kart graficznych

Problems of Corneal Endothelial Image Binarization

In this paper we present two methods of binarization of corneal endothelial images. The binarization is a first step of advanced image analysis. Images of corneal endothelial obtained by the specular microscopy have a poor dynamic range and they are usually non-uniformly illuminated. The binarization endothelial images is not trivial. Two binarization algorithms are proposed. The output images are presented. The quality of algorithms is discussed

Konstrukcje wybranych środowisk dedykowanych do obliczeń rozproszonych

In this paper two technologies for distributed computations are presented – Apache Hadoop and XtreemOS. The first of them is widely used for web services. Its main purpose is an analysis of large data. The second one is developed to distribute tasks between cluster nodes regarding the available resources. This technologies differ in construction context, which should be considered when applied.W pracy tej zostały przedstawione dwie technologie do obliczeń rozproszonych – Apache Hadoop oraz XtreemOS. Pierwsza z nich jest szeroko stosowana dla usług sieciowych i internetowych. Druga technologia oferuje możliwość rozsyłania zadań pomiędzy węzły klastra, z uwzględnieniem wymaganych zasobów. Technologie te różnią się budową, co powinno być uwzględnione podczas wyboru dla danego problemu obliczeniowego oraz podczas implementacji

Information Extraction from Satellite-Based Polarimetric SAR Data Using Simulated Annealing and SIRT Methods and GPU Processing

The main goal of this research was to propose a new method of polarimetric SAR data decomposition that will extract additional polarimetric information from the Synthetic Aperture Radar (SAR) images compared to other existing decomposition methods. Most of the current decomposition methods are based on scattering, covariance or coherence matrices describing the radar wave-scattering phenomenon represented in a single pixel of an SAR image. A lot of different decomposition methods have been proposed up to now, but the problem is still open since it has no unique solution. In this research, a new polarimetric decomposition method is proposed that is based on polarimetric signature matrices. Such matrices may be used to reveal hidden information about the image target. Since polarimetric signatures (size 18 × 9) are much larger than scattering (size 2 × 2), covariance (size 3 × 3 or 4 × 4) or coherence (size 3 × 3 or 4 × 4) matrices, it was essential to use appropriate computational tools to calculate the results of the proposed decomposition method within an acceptable time frame. In order to estimate the effectiveness of the presented method, the obtained results were compared with the outcomes of another method of decomposition (Arii decomposition). The conducted research showed that the proposed solution, compared with Arii decomposition, does not overestimate the volume-scattering component in built-up areas and clearly separates objects within the mixed-up areas, where both building, vegetation and surfaces occur

Predictors of Death in Contemporary Adult Patients With Eisenmenger Syndrome:A Multicenter Study

Eisenmenger syndrome is associated with substantial morbidity and mortality. There is no consensus, however, on mortality risk stratification. We aimed to investigate survival and predictors of death in a large, contemporary cohort of Eisenmenger syndrome patients. In a multicenter approach, we identified adults with Eisenmenger syndrome under follow-up between 2000 and 2015. We examined survival and its association with clinical, electrocardiographic, echocardiographic, and laboratory parameters. We studied 1098 patients (median age, 34.4 years; range, 16.1-84.4 years; 65.1% female; 31.9% with Down syndrome). The majority had a posttricuspid defect (n=643, 58.6%), followed by patients with a complex (n=315, 28.7%) and pretricuspid lesion (n=140, 12.7%). Over a median follow-up of 3.1 years (interquartile range, 1.4-5.9), allowing for 4361.6 patient-years observation, 278 patients died and 6 underwent transplantation. Twelve parameters emerged as significant predictors of death on univariable analysis. On multivariable Cox regression analysis, only age (hazard ratio [HR], 1.41/10 years; 95% confidence interval [CI], 1.24-1.59; P <0.001), pretricuspid shunt (HR, 1.56; 95% CI, 1.02-2.39; P=0.041), oxygen saturation at rest (HR, 0.53/10%; 95% CI, 0.43-0.65; P <0.001), presence of sinus rhythm (HR, 0.53; 95% CI, 0.32-0.88; P=0.013), and presence of pericardial effusion (HR, 2.41; 95% CI, 1.59-3.66; P <0.001) remained significant predictors of death. There is significant premature mortality among contemporary adults with Eisenmenger syndrome. We report, herewith, a multivariable mortality risk stratification model based on 5 simple, noninvasive predictors of death in this populatio