Wyniki wyszukiwania - Biblioteka Nauki

1

Direct Monte-Carlo Simulation of a Detonation Wave in a Narrow Channel, Containing Flammable Gas

100%

Walenta Z. A. , Teodorczyk A. , Dąbkowski A. , Witkowski W.

Central European Journal of Energetic Materials

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2004

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tom Vol. 1, nr 1

51-61

EN

The research on gaseous detonation has recently become a very important issue, mainly due to safety reasons in connexion with increasing importance of gaseous fuels. To simulate detonation, the Direct Monte-Carlo Simulation technique has been used. This technique is known to be a very powerful tool for solving complex flow problems. Simple model of molecular collisions, making it possible to increase the thermal energy of gas in a way similar to the processes in the flame has been proposed. This model is capable of producing waves, having the features characteristic for detonation waves. Finally the efficiencies of two known methods of extinguishing detonation: cooling the gas by cold channel walls and cooling by an expansion wave have been checked.

2

An Adaptive Coarse Graining Method for Signal Transduction in Three Dimensions

100%

Archuleta M. N. , Edwards J. S. , McDermott J. E. , Resat H.

Fundamenta Informaticae

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2012

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tom Vol. 118, nr 4

371-384

EN

The spatio-temporal landscape of the plasma membrane regulates activation and signal transduction of membrane bound receptors by restricting their two-dimensional mobility and by inducing receptor clustering. This regulation also extends to complex formation between receptors and adaptor proteins, which are the intermediate signaling molecules involved in cellular signaling that relay the received cues from cell surface to cytoplasm and eventually to the nucleus. Although their investigation poses challenging technical difficulties, there is a crucial need to understand the impact of the receptor diffusivity, clustering, and spatial heterogeneity, and of receptor-adaptor protein complex formation on the cellular signal transduction patterns. Building upon our earlier studies, we have developed an adaptive coarse-grained Monte Carlo method that can be used to investigate the role of diffusion, clustering and membrane corralling on receptor association and receptor-adaptor protein complex formation dynamics in three dimensions. The new Monte Carlo lattice based approach allowed us to introduce spatial resolution on the 2-D plasma membrane and to model the cytoplasm in three-dimensions. Being a multi-resolution approach, our new method makes it possible to represent various parts of the cellular system at different levels of detail and enabled us to utilize the locally homogeneous assumption when justified (e.g., cytoplasmic region away from the cell membrane) and avoid its use when high spatial resolution is needed (e.g., cell membrane and cytoplasmic region near the membrane) while keeping the required computational complexity manageable. Our results have shown that diffusion has a significant impact on receptor-receptor dimerization and receptor-adaptor protein complex formation kinetics. We have observed an adaptor protein hopping mechanism where the receptor binding proteins may hop between receptors to form short-lived transient complexes. This increased residence time of the adaptor proteins near cell membrane and their ability to frequently change signaling partners may explain the increase in signaling efficiency when receptors are clustered. We also hypothesize that the adaptor protein hopping mechanism can cause concurrent or sequential activation of multiple signaling pathways, thus leading to crosstalk between diverse biological functions.

3

Management of innovation projects in SMEs in the Czech Republic

80%

Špaček M. , Vacik E.

Journal of Economics and Management

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2016

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tom 24

14-30

EN

There is prevailing understanding that large companies are mostly inclined to using sophisticated innovation management processes as well as other management tools like project portfolio management while SMEs are believed to take advantage of more simple and often intuitive approaches to innovation processes management. Therefore methodologies of Monte Carlo simulation (MC), Stage Gate Control Process (SGCP) and Post- -implementation review (PIR) were reprocessed into more simplistic implementation models so as to prove that these methods can be operated even by routine staffs in Czech SMEs. All the test performed proved that the applications of aforementioned methods increased the effectiveness of innovation projects management and generated added value for shareholders.

4

Sample Size and Structure for Multilevel Modelling : Monte Carlo Investigation for the Balanced Design

80%

Łaszkiewicz E.

Metody Ilościowe w Badaniach Ekonomicznych / Szkoła Główna Gospodarstwa Wiejskiego

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2013

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tom 14(XIV)

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nr nr 2

19-28

EN

The aim of the study is to examine the robustness of the estimates and standard errors in the case of different structure of the sample and its size. The two-level model with a random intercept, slope and fixed effects, estimated using maximum likelihood, was taken into account. We used Monte Carlo simulation, performed on a sample of the equipotent groups. (original abstract)

5

Monte Carlo approach to identification of maritime ferry operation process

80%

Otremba Z. , Soszyńska J. , Targowski W.

Journal of Polish Safety and Reliability Association

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2010

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tom Vol. 1, No. 1

187--192

EN

The paper is concerned with the identification of operation processes of complex technical systems. The convenient tools suggested for analyzing these complex technical systems operation processes are semi-markov modeling and Monte Carlo simulation. The paper describes the proposed approach as well as the possibility of its practical application to identification of the operation process of a maritime ferry.

6

History Dependent Viterbi Algorithm for Navigation Purposes of Line Following Robot

80%

Matczak G. , Mazurek P.

Image Processing & Communications

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2015

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tom Vol. 20, no. 4

5--11

EN

Line following robots are applied in numerous applications and the best performance could be obtained if the forward looking camera is applied. Variable light and line conditions influence the line estimation and quality of the robot navigation. Proposed History Dependent Viterbi Algorithm and Viterbi Algorithm are compared. Obtained results using Monte Carlo tests show improved performance of the proposed algorithm for assumed model.

7

List-mode reconstruction in 2D strip PET

80%

Białas P. , Kowal J. , Strzelecki A. , Bednarski T. , Czerwiński E. , Giergiel K. , Kapłon Ł. , Kochanowski A. , Korcyl G. , Kowalski P. , Kozik T. , Krzemień W. , Molenda M. , Moskal I. , Moskal P. , Niedźwiecki S. , Pałka M. , Pawlik M. , Raczyński L. , Rudy Z. , Salabura P. , Gupta-Sharma N. , Silarski M. , Słomski A. , Smyrski J. , Szymański K. , Wiślicki W. , Witkowski P. , Zieliński M. , Zoń N.

Bio-Algorithms and Med-Systems

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2014

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tom Vol. 10, no. 1

9--12

EN

Using a theory of list-mode maximum likelihood expectation-maximization (MLEM) algorithm, in this contribution, we present a derivation of the system response kernel for a novel positron emission tomography (PET) detector based on plastic scintillators.

8

Photoluminescence spectroscopy for the evaluation of band potential roughness of InGaN active layers

80%

Kazlauskas K. , Jursenas S. , Miasojedovas S. , Pobedinskas P. , Tamulaitis G. , Zukauskas A. , Ivanov V. Y. , Godlewski M.

Optica Applicata

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2006

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tom Vol. 36, nr 2-3

181-185

EN

Photoluminescence spectroscopy in combination with Monte Carlo simulation of exciton hopping is demonstrated to be a valuable tool for quantitative analysis of the band potential profile in active layers for InGaN-based light emitters. Recently proposed double-scaled potential profile model is used to reveal the scale of potential fluctuations in the individual In-rich regions as well as the dispersion of the average exciton localization energy in these regions. The influence of the different potential fluctuation scales on the stimulated emission threshold and luminescence decay time of highly excited InGaN active layers is studied.

9

Application of Monte Carlo simulation for the evaluation of measurements uncertainty

80%

Zakharov I. P. , Vodotyka S. V.

Metrology and Measurement Systems

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2008

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tom Vol. 15, nr 1

117-123

EN

The Monte Carlo procedure for evaluation of uncertainty in measurements is considered. Algorithms of formation correlation and non correlation data files of the input quantity estimated on types A and B are developed.

10

Wycena opcji barierowych - symulacje Monte Carlo z wykorzystaniem metod aproksymacji drugiego rzędu

80%

Staszczyk A.

Prace Naukowe / Uniwersytet Ekonomiczny w Katowicach

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2014

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tom Problemy społeczno-ekonomiczne w relacjach międzynarodowych : analiza modelowa rozwoju regionów

261-268

XX

Zadanie wyceny jakichkolwiek instrumentów pochodnych, mniej lub bardziej skomplikowanych, każdorazowo wymaga od wyceniającego rozważenia paru istotnych zagadnień. Jedną z kwestii, które należy rozpatrzyć, jest wybór modelu oraz metody wykorzystanej do samej wyceny. Na styku tych dwóch tematów może powstać problem dostosowania wybranego modelu do metod (narzędzi), jakie chce się wykorzystać w wycenie. W opracowaniu tym zostanie przedstawiona metoda aproksymacji ciągłego procesu stochastycznego w modelu Blacka-Scholesa, który zostanie wykorzystany do wyceny na przykładzie opcji egzotycznych, jakimi są opcje barierowe. (fragment tekstu)

11

New Virtual Porous Carbons Based on Carbon EDIP Potential and Monte Carlo Simulations

80%

Furmaniak S.

Computational Methods in Science and Technology

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2013

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tom Vol. 19, No. 1

47--57

EN

Using simple Metropolis Monte Carlo simulations, the series of virtual porous carbons (VPCs) is generated. During the computations, the carbon EDIP potential is employed. Structures in the series have systematically changing porosity due to the differences in the carbon density. The obtained VPCs are similar to the model proposed by Harris et al., but they do not show its main drawback, because they contain curved fullerene-like sheets, which are interconnected and form one three-dimensional structure. The porosity of VPCs is characterised using a simple geometrical method proposed by Bhattacharya and Gubbins. In order to confirm the reality of the obtained new model carbons and their usefulness for modelling of adsorption phenomena, Monte Carlo simulations of argon adsorption on them are performed. The obtained isotherms are analysed using standard adsorption methods like αs-plots, adsorption potential distributions curves and Dubinin-Astakhov model. The results reveal a close relationship between the systematic changes in the porosity and the adsorption properties. The observed regularities correspond with experimental observations and theoretical studies.

12

The Use of the Monte Carlo Method to Determine Optical Parameters of Tissue

80%

Domański G. , Konarzewski B. , Pawłowski Z. , Zaremba K. , Marzec J. , Trybuła A. , Kurjata R.

Polish Journal of Medical Physics And Engineering

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2007

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tom 13

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nr 1

23-32

EN

The paper presents the use of the Monte Carlo method to determine the optical parameters of tissue from steady-state diffuse reflectance measurements.

13

MCNP simulation of the dose distribution in liver cancer treatment for BNC therapy

80%

Krstic D. , Jovanovic Z. , Markovic V. , Nikezic D. , Urosevic V.

Open Physics

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2014

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tom 12

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nr 10

714-718

EN

The Boron Neutron Capture Therapy (BNCT) is based on selective uptake of boron in tumour tissue compared to the surrounding normal tissue. Infusion of compounds with boron is followed by irradiation with neutrons. Neutron capture on 10B, which gives rise to an alpha particle and recoiled 7Li ion, enables the therapeutic dose to be delivered to tumour tissue while healthy tissue can be spared. Here, therapeutic abilities of BNCT were studied for possible treatment of liver cancer using thermal and epithermal neutron beam. For neutron transport MCNP software was used and doses in organs of interest in ORNL phantom were evaluated. Phantom organs were filled with voxels in order to obtain depth-dose distributions in them. The result suggests that BNCT using an epithermal neutron beam could be applied for liver cancer treatment.

14

Economic Assessment of Investment in Electric Buses and CNG Buses – A Case Study of a Public Transport Company

80%

Fabianová J. , Janeková J.

Advances in Science and Technology. Research Journal

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2022

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tom Vol. 16, no 4

96--105

EN

The article deals with green investment focused on urban public transport. This work presents a holistic approach to evaluating investments in electric and CNG buses, i.e., the economic efficiency assessment, including the risk aspect. The investment project is assessed in terms of the source of funding and risk factors affecting the profitability of the project. A non-repayable subsidy from the European Social Fund in the amount of 0%, 25%, 50% and 90% of investment costs is considered. Economic efficiency is assessed in terms of profitability through the financial criterion Net Present Value (NPV) and risk using mean NPV and standard deviation. The result of the evaluation of the variants of the investment project is that the investment project without the support of non-repayable resources is loss-making. With a low level of financial support, it is more economical to procure CNG buses. With a higher level of financial support, investments in electric buses are more profitable, due to lower operating costs

15

Modeling of light transmittance measurement in a finite layer of whole blood - a collimated transmittance problem in Monte carlo simulation and diffusion model

80%

Mroczka J. , Szczepanowski R.

Optica Applicata

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2005

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tom Vol. 35, nr 2

311-331

EN

The paper presents the modeling of transmittance measurement in a finite layer of whole blood. To describe light propagation in whole blood medium, a Monte Carlo simulation was used. The propagation of light in whole blood medium in the model required the assumption of photon transport approximation in highly scattering media. We have analyzed collimated-diffuse transmittance, which depended on the technique of free path length simulation. The Monte Carlo simulation was compared with the diffusion model designed for a finite incident light beam and available measurement data of whole blood optical density. The research revealed that discrepancy between the models discussed may be attributed to inaccuracy of the diffusion model due to an increase of anisotropic radiance under the thin sample conditions. Moreover, comparison of the Monte Carlo simulation versus measurement data showed that adding off-sets enabled agreement between them for hematocrit up to 60-70%, which is sufficient for many applications in oximetry. In fact, discrepancy in the Monte Carlo simulation, requiring off-sets to fit measurement data, most likely originates from measurement problem, such as divergence of light source or perturbation of light beam.

16

Monte Carlo simulation-based reliability model for the PSA of a radioactive waste repository

80%

Cadini F. , Avram D. , Zio E. , Luce A. , Taglioni A.

Journal of Polish Safety and Reliability Association

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2010

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tom Vol. 1, No. 1

43--50

EN

Disposal facilities for radioactive wastes comprise a series of engineered barriers whose purpose is to contain the radionuclides until their radiation hazard has decreased to acceptable levels. In this regard, it is required that the long-term functionality of the system of barriers be evaluated by a quantitative risk analysis procedure, also called performance assessment. In this paper, a Monte Carlo simulation-based reliability model is propounded for the preliminary analysis of the safety performance of a radioactive waste repository, accounting also for barrier degradation processes. The model strengths are: simplicity, chich allows ease of computation, and flexibility, which allows modification to account for various physical aspects and inter-comparison of their effects. An application to a case study of literature is presented to validate the approach and demonstrate its flexibility.

17

Porównanie wpływu strumienia wstecznego na generowaną koncentrację gazu w systemie wzorca IMGC, wyznaczonego na drodze pomiaru i symulacji Monte-Carlo

80%

Calcatelli A. , Niwiński M. , Szwemin P.

Elektronika : konstrukcje, technologie, zastosowania

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2004

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tom Vol. 45, nr 10

37-38

PL

Metoda Monte-Carlo jest często stosowana do wyznaczania parametrów stanu gazu w systemach wzorców próżni. W pracy podjęto próbę weryfikacji założeń modelu symulacyjnego przy wykorzystaniu zestawienia wyników otrzymanych na drodze symulacji i pomiaru. Wyniki różnią się od siebie na poziomie 2x10⁻³, co potwierdza tezę o poprawności przyjętego modelu rozpraszania cząsteczek gazu na powierzchni ścian układu kalibracyjnego.

EN

The parameters of the gas state are often determined by the means of Monte-Carlo simulation. The main aim of this work was to verify the assumptions of simulation model by comparison the results obtained by measurement to the results of computations. The results obtained by experimental method and by simulation are in agreement wihin the 2x10⁻³. From this fact, we can conclude that the assumption of cosine law (which describes the scattering process) is reasonable.

18

Simulation approach for modeling of dynamic reliability using time dependent acyclic graph

80%

Briš R. , Praaks P.

Eksploatacja i Niezawodność

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2006

|

tom nr 2

26-28

EN

The dynamic reliability approach takes into account changes (evolution) of the system structure (hardware). For instance, the dynamic reliability allows modeling a human operator (or an electronic control system) naturally. In these cases, the structure of the system is usually changed in order to keep the functionality and/or safety of the system. The main purpose of the paper is to illustrate, by means of a model example, the ability of acyclic oriented graph, terminal nodes of which are programmable components, to model simple dynamic system and to assess its performance via Monte-Carlo simulations. To demonstrate the availability of our framework a test case study with the deterministic evolution is presented. The here presented numerical results are in agreement with the exact analytical solution.

19

Nonequilibrium model on Archimedean lattices

80%

Lima F.

Open Physics

|

2014

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tom 12

|

nr 3

185-191

EN

On (4, 6, 12) and (4, 82) Archimedean lattices, the critical properties of the majority-vote model are considered and studied using the Glauber transition rate proposed by Kwak et al. [Kwak et al., Phys. Rev. E, 75, 061110 (2007)] rather than the traditional majority-vote with noise [Oliveira, J. Stat. Phys. 66, 273 (1992)]. We obtain T c and the critical exponents for this Glauber rate from extensive Monte Carlo studies and finite size scaling. The calculated values of the critical temperatures and Binder cumulant are T c = 0.651(3) and U 4* = 0.612(5), and T c = 0.667(2) and U 4* = 0.613(5), for (4, 6, 12) and (4, 82) lattices respectively, while the exponent (ratios) β/ν, γ/ν and 1/ν are respectively: 0.105(8), 1.48(11) and 1.16(5) for (4, 6, 12); and 0.113(2), 1.60(4) and 0.84(6) for (4, 82) lattices. The usual Ising model and the majority-vote model on previously studied regular lattices or complex networks differ from our new results.

20

Porównanie generatorów liczb pseudolosowych

80%

Sulewski P.

Wiadomości Statystyczne

|

2019

|

nr nr 7

5-31

XX

Losowanie prób w badaniach statystycznych i w obliczeniach numerycznych, jak również symulacyjne badanie modeli probabilistycznych właściwie we wszystkich dziedzinach wiedzy wymagają wyposażenia komputera w generatory liczb pseudolosowych. Głównym celem pracy jest porównanie generatorów liczb pseudolosowych normalnych na podstawie ich analizy dokonanej za pomocą różnego rodzaju kryteriów. Zbadano właściwości 12 generatorów liczb pseudolosowych o rozkładzie normalnym. Zaproponowano rozszerzenie rodziny generatorów o dwa tzw. generatory aplikacyjne oraz przyjęcie nowego podejścia do sprawdzania jakości generatorów. Przedstawiono narzędzie przygotowane w języku C++ oraz w języku Visual Basic for Application (VBA) do prowadzenia samodzielnych badań z użyciem generatorów. Symulacje Monte Carlo przeprowadzono w języku C++, a obliczenia wykonano w edytorze VBA przy użyciu arkusza kalkulacyjnego Microsoft Excel 2016. Analiza uzyskanych wyników wskazuje, że najlepsze właściwości mają generatory: MP Monty Pythona, R, Biegun oraz Ziggurat. Najmniej użyteczne okazują się generatory: BM Boxa-Mullera, Wallace'a, Iloraz oraz Excel. (abstrakt oryginalny)

EN

The sampling in statistical surveys and numerical calculations as well as simulation testing of probabilistic models in virtually all fields of knowledge require a computer endowed with pseudorandom numbers generators. The main goal of the study is to compare the normal random number generators using various criteria. The properties of 12 random number generators for a normal distribution were investigated. Then, the family of generators was extended by two so-called application generators and a new approach for checking the quality of generators was adopted. A ready-made tool prepared in C++ and in Visual Basic for Application (VBA) for conducting self-contained research using generators was presented. All Monte Carlo simulations were carried out in C++, while the calculations were performed in the VBA editor using the Microsoft Excel 2016 spreadsheet. The analysis of the obtained results shows that the generators with best properties are: MP Monty Python, R, Biegun and Ziggurat. The worst generators, are: BM Box-Muller, Wallace, Iloraz and Excel. (original abstract)