Wyniki wyszukiwania - Biblioteka Nauki

1

The use of simulation methods to determine the maximum dimensions of the ship capable to maneuvring on the selected sea area

100%

Czaplewski K. , Zwolan P.

Annual of Navigation

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2011

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tom No. 18

37--44

EN

The paper presents one of the methods to determine the maximum vessel size allowed for the maneuver on tested sea area or harbour. This method is based on the Navi - Trainer PRO 5000 simulator by Transas Marine available to the authors at the Institute of Navigation and Hydrography of Naval Academy of Gdynia. In the paper was described the possible use of additional simulator software components to generate the necessary virtual sea area. The next stage of research work was making several tests based on the created virtual harbour. These simulations tests are carried out under variable weather conditions for various vessel sizes and maneuvering characteristics. The result of simulation test are very important for determine the parameters of the maximum vessel size and hydro-meteorological conditions allowing safe navigation.

2

O primenenii metodov cislennogo modelirovania v zadacah identifikacii poristyh kollektorov

80%

Antonenko M. N. , Pavlukova E. R. , Jędrzejowska-Tyczkowska H.

Prace Naukowe Instytutu Nafty i Gazu

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2010

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tom nr 170 wyd. konferencyjne

529--531

EN

The paper presents the method for studying seismic wave propagation in соmрlех geological media with the use of numerical simulation methods. Special attention is paid to investigation оf wave-field evolution in randomly inhomogeneous porous media. Vector wave equation in assumption of small deformations has been used as the set of governing equations to describe wave processes. Obtained set of hyperbolic equations is solved by finite differences method using high-performance computing system. These results can be applied in development of porous collector exploration procedure.

3

Selected problems of sensitivity and reliability of a jack-up platform

80%

Rozmarynowski B. , Mikulski T.

Polish Maritime Research

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2018

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tom nr 1

77--84

EN

The paper deals with sensitivity and reliability applications to numerical studies of an off-shore platform model. Structural parameters and sea conditions are referred to the Baltic jack-up drilling platform. The sudy aims at the influence of particular basic variables on static and dynamic response as well as the probability of failure due to water waves and wind loads. The paper presents the sensitivity approach to a generalized eigenvalue problem and evaluation of the performace functions. The first order time-invariant problems of structural reliability analysis are under concern.

4

Symulacyjna analiza wpływu liczby i rozmieszczenia luk niesystematycznych na dokładność prognoz

80%

Oesterreich M.

Econometrics. Ekonometria. Advances in Applied Data Analytics

|

2015

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nr 2 (48)

78-88

EN

In this paper there was conducted a statistical analysis of the impact of the distribution of unsystematic gaps on the accouracy of inter- and extrapolative forecasts in the seasonal time series. In the analysis, as variable, there was used the average period of stay of tourists in accommodation establishments in the West Pomeranian Voivodeship in the years 2008-2013. In calculations there were used simulation methods to generate ten thousand sets of gaps for the three variants, differed in the number of gaps. For all the set and variants of gaps, there were estimated time series models with exponential trend and relatively-fixed seasonality. In the next step there were built inter- and extrapolative forecasts and calculated their relative errors (MAPE). In the analysis there were used R program and Statistica 10.

5

Metody symulacji statycznej sieci gazowej

80%

Gawron M.

Zeszyty Naukowe. Inżynieria Środowiska / Uniwersytet Zielonogórski

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2011

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tom nr 144 (24)

40-47

PL

W artykule przedstawiono metody symulacji statycznej sieci gazowej niskiego ciśnienia charakteryzującej się szybkimi zmianami ciśnienia I prędkości. Przedstawiono nieliniowe algebraiczne modele matematyczne służące do obliczania zależności pomiędzy spadkiem ciśnienia, strumieniem przepływającego gazu, wymiarami geometrycznymi rury gazociągu oraz właściwościami gazu.

EN

The article presents methods for the simulation of static low-pressure gas network is characterized by rapid changes in pressure and velocity. Presented nonlinear algebraic mathematical models for calculating the relationship between pressure drop, the gas flow stream, geometric dimensions of pipes and pipeline gas properties.

6

Towards Simulation Based Design

80%

Skoberla R. , Skarka W.

Machine Dynamics Research

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2017

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tom Vol. 41, No. 4

173--181

EN

This article presents the experience of the Smart Power team in applying advanced simulation methods. The basic techniques used in the development of complex technical objects have been characterized. The arguments for adopting the procedure were presented. Major areas, where advanced methods are required, are indicated.

7

Analytical and simulation determination of order picking time in a low storage warehouse for shared storage systems

80%

DMYTRÓW K.

Operations Research and Decisions

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2022

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tom 32

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nr 2

34-51

EN

The aim of the research is comparison between average order picking times obtained using the analytical model and simulation methods for shared storage systems. We also compare the results obtained with the results obtained for dedicated storage. We assume the random and ABC-class storage (with within and across aisle storage policies). We select the locations by means of the TOPSIS method for two take-out strategies: quantity adjustment (QA) and priority of partial units (PPU). We determine the route by using s-shape and return heuristics. In most cases, the simulated average order picking times are shorter than the analytical ones. It results from not considering the criteria’ weights in calculation of the analytical order picking time. Also, the results for shared storage with QA strategy are in most cases better than for dedicated storage. This might imply an advantage of shared over dedicated storage, but needs further confirmation.

8

Petri Nets for Modelling and Analysing Trophic Networks

80%

Baldan P. , Bocci M. , Brigolin D. , Cocco N. , Heiner M. , Simeoni M.

Fundamenta Informaticae

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2018

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tom Vol. 160, nr 1/2

27--52

EN

We consider trophic networks, a kind of networks used in ecology to represent feeding interactions (what-eats-what) in an ecosystem. Starting from the observation that trophic networks can be naturally modelled as Petri nets, we explore the possibility of using Petri nets for the analysis and simulation of trophic networks. We define and discuss different continuous Petri net models, whose level of accuracy depends on the information available for the modelled trophic network. The simplest Petri net model we construct just relies on the topology of the network. We also propose a technique for deriving a more refined model that embeds into the Petri net the known constraints on the transition rates that represent the knowledge on metabolism and diet of the species in the network. Finally, if the information of the biomass amounts for each species at steady state is available, we discuss a way of further refining the Petri net model in order to represent dynamic behaviour. We apply our Petri net technology to a case study of the Venice lagoon and analyse the results.

9

Spectral dynamic analysis of a stationary jack-up platform

80%

Rozmarynowski B.

Polish Maritime Research

|

2019

|

tom nr 1

40--48

EN

The paper refers to the dynamic short-term response analysis of the Baltic steel drilling platform (see Fig.2) in a random sea-state represented by one-dimensional wave spectrum proposed by Striekalov and Massel, which is recommended for the Baltic Sea area. The Baltic drilling platform is a jack-up type platform for the exploration and exploitation of oil under the Baltic Sea. The presented analysis deals with the stationary phase of the platform life when its legs are fixed in the sea bottom. The submerged elements of jack-up platforms are relatively slender, thus to assess the in-line wave forces a modified Morison equation is justified. The application of frequency transfer functions to offshore vibration systems leads to structural response spectra whose input is defined by the wave elevation and wind velocity spectra. The analysis can be applied also to support structures for offshore wind turbines.

10

Zastosowanie metod symulacyjnych do przestrzennego prognozowania obciążeń elektrycznych

70%

Kamińska-Chuchmała A. , Wilczyński A.

Rynek Energii

|

2009

|

tom nr 1

2-9

PL

Artykuł zawiera przegląd metod symulacyjnych zastosowanych do przestrzennego (w układzie 3D) prognozowania obciążeń elektrycznych. Prognoza powierzchniowego rozkładu obciążeń jest przydatna w planowaniu rozwoju i eksploatacji systemów elektroenergetycznych, szczególnie w sytuacji rozwijania konkurencji na rynku energii elektrycznej oraz wzmożonej aktywności inwestorów gospodarczych. W artykule omówiono algorytmy prognozy i wskazano ich modyfikacje. Wyodrębniono w algorytmach dwa moduły: obszarowy i czasowy, przedstawiając dokładniej ich działanie. Następnie przedstawiono geostatystyczną metodę symulacyjną Turning Bands, którą zastosowano do modelowania obciążeń elektrycznych dla obszaru Polski oraz prognozowania z wyprzedzeniem czasowym wynoszącym 1 rok.

EN

The paper contains simulation methods review applied to spatial (3D coordinate system) electric load forecasting. The surface of electric load forecast is necessary in planning the development and operation of power transmission and distribution networks, especially when a competitive energy market is being developed and intensive economical investors activity. Algorithms of forecast are being discussed in the paper and indicated their modification. Two modules in algorithms are being separated: spatial and temporal, then presented more precisely. Next, the Turning Bands geostatistic simulation method is being presented which is applied to modeling electric loads for the area of Poland and forecast for one year ahead.

11

Power of S-kR-RRWW-automata

70%

Hoffmann P.

Fundamenta Informaticae

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2015

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tom Vol. 136, nr 1/2

85--112

EN

Single k-reversible restarting automata are a special version of restarting automata which can be effectively learned from samples. We show that their power lies between GCSL and CSL. We show that their subclasses form an infinite hierarchy of classes of languages with respect to the reversibility level k and we also show that limiting types of allowed rewrites lowers the power of the model. Finally, we study their relation to strictly locally testable restarting automata.

12

Risk analysis of collision between passenger ferry and chemical tanker in the western zone of the Baltic Sea

70%

Przywarty M. , Gucma L. , Marcjan K. , Bąk A.

Polish Maritime Research

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2015

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tom nr 2

3--8

EN

This paper presents assumptions and process of the forming of a risk assessment model for collision between a passenger ferry departing from or approaching port of Świnoujście and a chemical tanker carrying a dangerous cargo. In order to assess navigational safety on the basis of data obtained from AIS system, were prepared probabilistic domains of ships, which made it possible to estimate number of navigational incidents as well as their spatial distribution , that consequently allowed to determine potentially dangerous areas. The next phase was formulation of a simulative model intended for the calculating of probability of collision between the ferry and chemical tanker as well as the determining of characteristic scenarios for such collision. This paper presents also an analysis of consequences of the collision with taking into consideration a damage of cargo tanks.

13

Genetic algorithms-aided reliability analysis

70%

Harnpornchai N.

Journal of Polish Safety and Reliability Association

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2009

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tom Vol. 1

145--156

EN

A hybrid procedure of Genetic Algorithms (GAs) and reliability analysis is described, discussed, and summarized. The procedure is specifically referred to as a Genetic Algorithms-aided (GAs-aided) reliability analysis. Two classes of GAs, namely simple GAs and multimodal GAs, are introduced to solve a number of important problems in reliability analysis. The problems cover the determination of Point of Maximum Likelihood in failure domain (PML), the computation of failure probability using the GAs-determined PML, and the determination of multiple design points. The MCS-based method using the GAs-determined PML is specifically implemented in the so-called an Importance Sampling around PML (ISPML). The application of GAs to each respective problem is then demonstrated via numerical examples in order to clarify the procedures. With an aid from GAs, reliability analysis is possible even if there is no information about the geometry or landscape of limit state surfaces and the total number of crucial likelihood points. In addition, GAs significantly improve the computational efficiency and realize the analysis of rare events under constrained computational resources. The implementation of GAs to reliability analysis for building up the hybrid procedure is readily because of their algorithmic simplicity.

14

Reliability analysis of a system subjected to two-state operation process

70%

Kuligowska E.

Zeszyty Naukowe / Akademia Morska w Szczecinie

|

2013

|

tom nr 36 (108) z. 1

100--104

EN

The paper presents analytical and Monte Carlo simulation methods applied to the reliability evaluation of a system operating at two different operation states. A semi-Markov process is applied to construct the system operation model and its main characteristics are determined. Analytical linking of this operation model with the system reliability model is proposed to get a general reliability model of the system operating at two varying operation conditions and to find its reliability characteristics. The application of Monte Carlo simulation based on this general model to the reliability evaluation of this system is proposed as well. The results obtained from those two considered methods are evaluated.

15

Research method of dynamic capability of an actuating block of the SSP-FK aircraft fire suppression system in false alarm aspect

70%

Szelmanowski A. , Zieja M. , Głyda K. , Tokarski T.

Journal of KONES

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2016

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tom Vol. 23, No. 3

525--531

EN

Numerous cases of self-activation of the SSP-FK aircraft fire suppression system (including commissioning of valves and extinguishing tanks) testify about the fact that it is not yet fully understood in the technical aspect, and because of the performed role on the aircraft is the basic element to ensure flight safety. Solving problems with false fire signalling of the SSP-FK system is an important issue for the safe operation of aircraft and military helicopters, because it is preventive (to warn the crew of the possibility of fire) and rescue system (aiming at extinguish the fire) in each phase of a flight. In addition, the SSP-FK system is used on many types of military aircraft (including helicopters from W-3/3W/3WA/3PL and Mi/8/14/17/24 family as well as An-28 and Tu-154M aircraft. The paper presents selected results of work in the Air Force Institute of Technology in the study of SSP-FK fire suppression system (as one of the main protection systems on-board) used on many types of military aircraft operated in the Polish Armed Forces. In determining the conditions of the false signalling of fire, simulation models of action blocks implementing of the SSP-FK fire suppression system were developed. The research on simulation models was performed in Matlab-Simulink and Circuit-Maker computing packages. The results of these works were used to diagnose selected modules and blocks of the SSP-FK system during the study of actual cases of their false activation.

16

Discrete Tomography in MRI : a Simulation Study

70%

Segers H. , Palenstijn W. J. , Batenburg K. J. , Sijbers J.

Fundamenta Informaticae

|

2013

|

tom Vol. 125, nr 3/4

223--237

EN

Discrete tomography (DT) is concerned with the tomographic reconstruction of images that consist of only a small number of grey levels. Recently, DART, a practical algorithm was introduced for discrete tomography, which was validated in the domain of X-ray computed and electron tomography. In this paper, DART is introduced for magnetic resonance imaging. Using simulation experiments, it is shown that the proposed MRI-DART algorithm is capable of computing high quality reconstructions from substantially fewer data compared to state-of-the-art MRI reconstruction methods.

17

Simulation Methods in Development of Rehabilitation Exoskeleton

70%

Skarka W. , Skoberla R.

Machine Dynamics Research

|

2015

|

tom Vol. 39, No. 3

137-145

EN

The paper presents some aspects of selection and verification of design features of upper limb exoskeleton intended for the purpose of rehabilitation with particular emphasis on the aspects of verification of these features for different plans for rehabilitation and rehabilitation exercises. We present a method of numerical simulation together with their exemplary results for as given knot of construction in the context of assigned plan of exercises and their requirements. Using simulation methods can not only verify the selection of system components, but also the design and analysis of rehabilitation programs.

18

Wykorzystanie wybranych metod symulacyjnych w obliczeniach probabilistycznego rozpływu mocy

60%

Przygrodzki M. , Lubicki W.

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

|

2017

|

tom Nr 53

61--64

PL

Rozpływ mocy jest zadaniem wyznaczenia wartości napięć węzłowych oraz obciążeń gałęziowych w danym stanie systemu elektroenergetycznego. W przypadku probabilistycznego rozpływu zarówno dane wejściowe zadania, jak i wyniki obliczeń mają postać rozkładów prawdopodobieństwa. Rozkłady te można określić dla zapotrzebowania na moc, dostępności i poziomu generacji mocy w węzłach oraz struktury układu sieciowego. W artykule przedstawiono wyniki porównania losowań przeprowadzonych metodą Monte Carlo oraz metodą LHS. Losowania te dotyczyły dostępności infrastruktury sieciowej. Obliczenia przeprowadzono w układzie sieciowym odwzorowującym krajową sieć zamkniętą 400 kV/220 kV/110 kV. Na podstawie przedstawionych wyników symulacji odniesiono się do możliwości wykorzystania metody LHS w prowadzeniu analiz probabilistycznego rozpływu mocy.

EN

Probabilistic power flow is such kind of power flow problem, for which the input data and calculation results have the form of probability distributions. Analogous to the deterministic power flow inputs are defined in the network nodes: the power and electricity demand, availability and level of power generation, defined as probability distributions. In addition, an input data structure is also the network system. The result of the calculation of power flow are probability distributions of voltage in grid nodes and branch power flows. The structure of the network, as part of the network model, understood as the availability of its individual components is a random variable. Variable distribution of binary: the element is on or off. Parameter of this distribution is the failure rate of the item, possibly increased by the rate of planned outage. Generally, the method of determining probabilistic power flow can be divided into simulation, analysis and approximation. Approximation and analytical methods are often combined into one group defined as an analytical method. To determine the value of the input data for the n-th simulation can be used different simulation methods, including Monte Carlo and Latin Hypercube Sampling (LHS). The article presents the results of the comparison draws conducted using Monte Carlo method and LHS. Drawings are concerned the availability of network infrastructure (lines). The calculations were carried out for the national 400 kV, 220 kV and 110 kV network. Simulation result shows possibility of Monte Carlo and LHS method usage for probabilistic power flow calculation.

19

Use of LHS sampling to calculate probabilistic power flow

60%

Przygrodzki M. , Lubicki W.

Acta Energetica

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2017

|

tom nr 2

189--196

EN

Power flow is the task of determining node voltages and branch loads in a given state of the power system. In the case of probabilistic flow, the task’s input data and calculation results alike are in the form of probability distributions. These distributions can be specified for the power demand, power generation availability and levels in nodes, and grid configuration. Elements that make up the grid configuration may be assigned a binary distribution, the result of which determines the element’s status (on or off). This distribution characteristic parameter is the failure rate of the element. This paper presents the results of a comparison of Monte Carlo and LHS sampling. The sampling concerned grid infrastructure availability. Calculations were made for two grid systems with different sizes corresponding to the test model (ca. 50 branches) and the national transmission grid model (over 400 branches). Based on the results, conclusions were drawn as to the possibility of using LHS simulation in the probabilistic power flow calculation.

PL

Rozpływ mocy jest zadaniem wyznaczenia wartości napięć węzłowych oraz obciążeń gałęziowych w danym stanie systemu elektroenergetycznego. W przypadku probabilistycznego rozpływu zarówno dane wejściowe zadania, jak i wyniki obliczeń mają postać rozkładów prawdopodobieństwa. Rozkłady te można określić dla zapotrzebowania na moc, dostępności i poziomu generacji mocy w węzłach oraz konfiguracji układu sieciowego. Elementom tworzącym konfigurację układu sieciowego można przypisać rozkład dwustanowy, w wyniku którego określa się stan elementu (element pracuje lub jest wyłączony). Parametrem charakterystycznym tego rozkładu jest współczynnik awaryjności danego elementu. W artykule przedstawiono wyniki porównania losowań przeprowadzonych metodą Monte Carlo oraz metodą LHS. Losowania te dotyczyły dostępności infrastruktury sieciowej. Obliczenia przeprowadzono dla dwóch układów sieciowych o różnej liczebności odpowiadającej modelowi testowemu (około 50 gałęzi) oraz modelowi krajowej sieci przesyłowej (ponad 400 gałęzi). Na podstawie uzyskanych wyników sformułowano wnioski co do możliwości wykorzystania symulacji metodą LHS w obliczeniach probabilistycznego rozpływu mocy.

20

Dyskretne metody symulacji zjawisk przepływowych w gazach i cieczach

60%

Wolszakiewicz T. , Walenta Z. A.

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

|

2013

|

tom Vol. 4, Nr 4 (14)

67-76

PL

W pracy rozpatrzone zostały dwie metody numerycznej symulacji zjawisk przepływowych w ośrodkach gazowych i ciekłych, oparte na molekularnym opisie ośrodka: metoda Bezpośredniej Symulacji Monte Carlo oraz metoda Dynamiki Molekularnej. Metody te pozwalają na modelowanie w sposób bezpośredni przebiegu reakcji chemicznych, oddziaływania ośrodka ze ściankami ich zaletą jest także względna łatwość dostosowania się do skomplikowanej geometrii. Wadą są długie czasy obliczeń, co jednak może być przezwyciężone przez wykorzystanie coraz powszechniej dostępnych komputerów o dużej szybkości obliczeń.

EN

The paper presents two methods of simulation of flow phenomena in gases and liquids based on molecular description of the medium: the Direct Simulation Monte Carlo method and the Molecular Dynamics method. These methods offer the possibility of direct modelling of chemical reactions and interactions of the medium with solid walls. Apart from that they have the advantage of relatively easy adaptation to complex geometries. Their main disadvantage is the long computing time, which, however, may be overcome with the use of the modern, fast computers presently available.