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1

High dimensional model representation for reliability analyses of complex rock–soil slope stability

Vessia G., Kozubal J., Puła W.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 4

954--963

EN

The high-dimensional model representation (HDMR) and its modifications, the fractional HDMR (FHDMR) and hybrid HDMR (HHDMR), are new tools for calculating reliability indexes in stability analyses when several variables with large uncertainties are used to describe rock and soil behaviours. Plain HDMR utilises an inverse reliability analysis for the study of unknown design parameters associated with target reliability index values. This approach uses implicit response functions, named limit state functions, according to the response surface method (RSM). In this study, both the FHDMR and HHDMR are applied to the reliability index calculation of safety factors related to the stability analyses of sliding failure mechanisms in complex formations. These two methods improve the computational efficiency of the RSM in reliability index calculations compared to the HDMR. A case study of Carpathian Flysch rock–soil slopes is presented, and the efficiency of the reliability index calculation is estimated by comparing results with ones from neural network application.

2

Influence of fuel injector holes diameter on parameters of combustion process in the cylinder of the marine 4-stroke Diesel engine

Kowalski J.

Journal of Polish CIMEEAC

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2016

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Vol. 11, no 1

95--102

EN

The paper presents an analysis of the influence of the fuel injector nozzle holes diameter on parameters of the brake-up, evaporation and combustion process in the cylinder of the marine 4-stroke Diesel engine. Presented analysis was prepared in the basis on computational fluid dynamic model. Initial and boundary conditions of the model as well as data used to model validation were collected during the laboratory study. Calculations were conducted for nominal fuel holes diameter equals 0.375mm and diameters increased and decreased by 50μm and 100μm respectively. According to presented results the increase of the diameter of fuel nozzle holes causes the increase of fuel Sauter’s mean diameter in the initial stage of the injection process and the decrease of fuel process evaporation. The result of this phenomenon is the slowdown of the initial stage of the combustion process and the decrease of both pressure and temperature of combustion.

3

The analysis of the ECFM-3Z combustion model in the marine 4-stroke engine for the exhaust gas composition

Kowalski J.

Journal of Polish CIMAC

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2014

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Vol. 9, no 1

95--102

EN

The paper presents ECFM-3Z combustion model analysis in the marine, 4-stroke diesel engine. The purpose of the modeling was to determine the composition of the exhaust gas. This composition depends on the composition of the combustible mixture, combustion time and thermodynamic conditions prevailing in the engine cylinder during the working process. Mentioned parameters are variable in time and space, and therefore require the use of 3-dimensional model based on the finite volume method, taking into account the fuel injection, brake-up and evaporation, mixing with air, auto-ignition and combustion. All models presented in the literature are adapted to the parameters of relatively small engines. Different marine engine parameters require significant modifications taking into account the heat exchange with the structural elements of the engine, leakage through piston rings and energy losses by riction. It should also be noted that dimensions of the marine engine require careful optimization of spatial moving meshes according to computation time and quality of results. Paper presents influence of mixing time, start of injection and autoignition delay on modeling results of the exhaust gas composition.

4

Assessment of the 3-D combustion model in the marine 4-stroke engine

Kowalski J.

Journal of Polish CIMAC

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2014

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Vol. 9, no 1

79--86

EN

The aim of this research is to formation of the model of combustion process in the marine, 4 -stroke, diesel engine. The chosen object of research is a laboratory AL25/30 engine. For achievement of the aim, laboratory measurements are made and the results are used to determine the boundary and initial conditions. In addition, measurements of the fuel injection shape are made on the test bench and are made a faithful geometric model of structural components of the engine cylinder. The obtained data has been implemented in the three - dimensional model comprising the fuel injection phenomena, the brake - up and the evaporation of fuel, auto - ignition, flame propagation and heat exchange with the structural elements of the engine cylinder. As a result of activities succeeded in creating a model of the combustion process in the cylinder, which has been positively validated due to the maximum combustion pressure and the temperature of the exhaust gases. Obtained results of calculations also allowed verifying the assumption of negligible auto-ignition delay. The adopted ECFM - 3Z model of the ignition and combustion, used for modeling of combustion in diesel engines, showed the calculated size of the auto - ignition delay of 7 - 8 ° CA.

5

Zarządzanie dynamiczne : podejście wielowymiarowe

Rafało M.

Ekonomia i Zarządzanie

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2013

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Vol. 5, no. 1

65--83

PL

Organizacje, chcąc utrzymać przewagę konkurencyjną, muszą stale poszukiwać innowacji w swoich działaniach. Nie dotyczy to tylko oferowania innowacyjnych produktów czy nowoczesnych metod wytwarzania. Są to ważne aspekty budowania przewagi, ale jak pokazują badania, innowacyjność ważna jest także w budowaniu relacji z otoczeniem czy w zarządzaniu operacyjnym. Szybkość działania, monitowanie otoczenia czy innowacyjność to wybrane narzędzia, które wykorzystują organizacje na dynamicznym rynku. Wielowymiarowy model zarządzania w turbulentnym otoczeniu pozwala na pomiar i śledzenie dojrzałości organizacji w poszczególnych aspektach (wymiarach) zarządzania dynamicznego.

EN

Organizations willing to sustain competitive advantage, must endeavor to innovation. Not only they need to offer innovative product or production method, they also must focus on relations with environment and effective operational management. Speed of acting, environmental scanning and innovation are tools used by organizations in turbulent environment. Multidimensional model of high speed management allows measuring and monitoring dynamic capabilities in all areas (dimensions).

6

Analiza wybranych nieparametrycznych metod automatycznej klasyfikacji obiektów wielowymiarowych w aplikacji do nieniszczącej detekcji uszkodzeń

Giżewski T., Wac-Włodarczyk A., Goleman R., Czerwiński D.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 9b

234-237

PL

Artykuł przedstawia problematykę nieparametrycznych metod klasyfikacji w odniesieniu do numerycznego modelu obiektu fizycznego. Głównym tematem jest analiza skuteczności algorytmów pod kątem zastosowań w nieniszczącej detekcji uszkodzeń. Szczególną uwagę zwrócono na parametryzację modelu, jako czynnika istotnego przy minimalizacji kosztów procesu uczenia.

EN

The article presents the discussion on nonparametric classification methods in relation to the numerical model of a physical object. The main theme is the analysis of algorithms in applications to non-destructive testing of ferromagnetic materials. The particular attention was given to model parameterization as a significant factor in minimizing the cost of the learning process.

7

Wielowymiarowe modele sterowania zapasami i ich zastosowanie

Wojna A., Kłodzińska A.

Badania Operacyjne i Decyzje

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2005

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nr 2

83-90

PL

W artykule przeprowadzono matematyczną formalizację wielowymiarowych modeli sterowania zapasami z wykorzystaniem procesów sum zmiennych losowych określonych na łańcuchu Markowa. Na podstawie tej formalizacji określono funkcję ryzyka funkcjonowania wielowymiarowych modeli sterowania zapasami. Rozpatrzono również zagadnienie analizy niezawodności funkcjonowania oraz ustalenia optymalnej struktury specjalnego systemu obsługi Markowa za pomocą określenia jego funkcji ryzyka.

EN

The multidimensional stock control that functions in a random Markov environment is considered. The mathematical formalization of this model was considered with the use of sums of the random variables de-fmed on the Markov chains. The authors introduce a definition of risk function of the type of downside risk measures and find the explicit formulas for its determinations. The example of the application of these formulas is provided: the tasks of the reliability and optimal configuration for the queueing problem are regarded. The formulas defining the function by the system parameters were obtained

8

Sensitivity to correlation in multivariate models

Žanic V., Žiha K.

Computer Assisted Mechanics and Engineering Sciences

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1998

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Vol. 5, nr 1

75-84

EN

The paper presents some aspects of the sensitivity analysis within the multivariate distribution models. The presented procedures are provided for engineering problems based on the Nataf model. The Nataf model involves the marginal distributions of the random variables and the correlation between them. Sensitivities are considered through derivatives with respect to the correlation coeffcients. The terms for the derivatives of the Nataf correlation coefficiens with respect to the given correlation coefficients are presented. The derivatives of the transformations between the random variables are given nex. The Cholesky decomposition and the spectral decomposition are applied. Derivatives of the Cholesky decomposition are obtained in the form of a recursive scheme. Dervatives of the eigenvalues and eigenvectors are obtained using perturbations. In addition, a comprehensive method for derivatives of distances and derivatives of angles between the directions is given. Finally, numerical examples are attached to illustrate the presented procedures.