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1

Simulating land use changes and environmental implications of transportation development in Barru Regency using cellular automata

Ali Mukti, Basri Yuni Andiyani, Haerani

Ecological Engineering & Environmental Technology

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2025

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Vol. 26, iss. 4

1--12

EN

The expansion of transportation infrastructure often induces significant changes in land use patterns within adjacent areas, accompanied by ecological impacts on natural landscapes and environmental sustainability. This study aims to project anticipated land use changes surrounding the construction zone of the Takkalasi-Bainange-Lawo road in Barru Regency, Indonesia, using the cellular automata (CA) approach integrated with geographic information systems (GIS). The simulation results reveal substantial land use transformations over the next two decades, including the conversion of six land use categories such as rice fields, mixed gardens, upland fields, and residential and industrial zones. Projections indicate a reduction in agricultural land, particularly rice fields, which also support local ecosystems, by approximately 6.2 hectares from 2023 to 2043, driven by increasing demands for residential and industrial development. Conversely, industrial zones are expected to expand significantly, with land converted from other categories such as rice fields and mixed gardens, potentially affecting biodiversity and ecological balance. This study provides critical insights for sustainable land use planning by addressing environmental impacts and the requirements of transportation infrastructure development.

2

Modeling land cover dynamics using Markov chain and cellular automata in Batang Regency

Sanjoto Tjaturahono Budi, Ramadhan Muhammad Fauzan, Aji Ananto

Ecological Engineering & Environmental Technology

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2025

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Vol. 26, iss. 2

342--350

EN

Land cover change is one of the impacts of the economic development process, also marked by urbanization. One form of urbanization is industrialization. Batang Regency is an area currently carrying out much industrial development, such as the steam power plant and the Batang integrated industrial area (KITB), which can become a centre of economic growth. Accessibility in Batang Regency is currently passed by the Toll Road and National Road, which can be one of the attractions for changes in land cover. This study aims to predict land-cover changes due to economic activities and compare the prediction results with applicable regulations. The method used is the cellular automata algorithm for 2032 and 2039. Land cover modelling is carried out based on data from 2015 to 2023. The selection of years is based on the Batang Regency spatial planning (RTRW) regulations. Accuracy test results using the relative operating characteristic (ROC) method show that the number is 0.86. The results of land cover predictions show that open land and agriculture tend to decline. Changes in land cover tend to occur in areas close to economic centres and highways. The agricultural area in the prediction results is lower than the planned area, indicating that the program to maintain agricultural land has been considered in the RTRW. The conversion of land that tends to be used as settlements is done in non-agriculture fields, such as forest areas and plantation areas.

3

Evaluation of land use and land cover changes on groundwater resources in the Pasi Watershed, Pasi Gusung Island, Selayar Islands

Musdalipah Fachrie, Hazairin Zubair, Arifuddin Akil, Saridayana Thamrin Putri

Ecological Engineering & Environmental Technology

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2025

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Vol. 26, iss. 3

301--314

EN

Water is of vital importance to ecosystems and human societies. Because of this, the UN Secretary-General has included the availability of clean water as one of the sustainable development goals (SDGs). This study examined the impact of land use and land cover (LULC) changes on groundwater availability in the Pasi watershed on Pasi Gusung Island, Selayar Islands. LULC changes significantly influence water balance as they determine infiltration and surface runoff patterns. Using cellular automata (CA) integrated with artificial neural network (ANN) modeling via the MOLUSCE plugin in QGIS, historical LULC data from 2014 to 2023 were examined and changes through 2033 were forecasted. The soil and water assessment tool (SWAT) was utilized to evaluate the impact of these changes on water availability. The analysis revealed significant LULC alterations, including the expansion of residential and agricultural areas, a decline in mangrove forests, and reduced groundwater recharge capacity. SWAT results suggest a potential reduction in groundwater storage due to decreased infiltration linked to LULC transformations. This study shows a close relationship between land use and land cover changes and fluctuations in groundwater availability in the Pasi watershed. Analysis of land cover from 2014 to 2023 and projections to 2033 show patterns of change that affect the hydrology of the area, including groundwater discharge and the balance between water availability and demand. Continued population growth pressures already limited water resources, creating a growing annual water deficit. This research provides strategic insights for developing sustainable water supply systems in response to projected land use change.

4

Full-field approaches for austenite-ferrite phase transformation simulations

Wermiński Mariusz, Sitko Mateusz, Madej Łukasz

Computer Methods in Materials Science

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2025

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Vol. 25, No. 4

5--30

EN

Understanding the local evolution of phase transformations in steels, particularly the γ (austenite) → α (ferrite) transformation, is crucial for controlling the microstructure and properties of steel components. Over recent decades, significant progress has been made in the numerical modeling of this complex phenomenon. This development has been driven by both scientific curiosity and industrial needs, especially in processes such as hot rolling, forging, thermal treatment, etc. The developed models have evolved from simple solutions based on local equilibrium to more complex approaches that consider local heterogeneities. Modern computational approaches, such as Phase-Field (PF), Level-Set (LS), Cellular Automata (CA), Monte Carlo (MC) or Vertex based simulations, allow for the precise reproduction of microstructural evolution considering local instabilities. They also enable the analysis of phase boundary motion in an explicit manner. These techniques also allow for direct integration with thermodynamic data and mechanical models, thereby better capturing the physical mechanisms of phase transformations, such as chemical composition, diffusion resistance, or the influence of deformation. An overview of the state of the art in this area is presented within the paper. The model’s concepts, assumptions, fundamental equations, advantages, limitations, and potential practical applications are summarized. Special attention is given to modeling the γ → α transformation by the Cellular Automata method. The importance of incorporating phenomena such as diffusion, nucleation, and growth is emphasized. The need for consistency between experimental results and simulations is also highlighted.

5

Study of DC voltage effects on the electrical treeing phenomenon in XLPE insulating materials

Medoukali Hemza, Zegnini Boubakeur, Guibadj Mossadek

Przegląd Elektrotechniczny

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2024

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R. 100, nr 2

290--293

EN

n this study, we present the propagation of electrical tree in solid insulation via dynamical simulation with cellular automata. Taking a specimen of XLPE dielectric situated between two electrodes under DC voltage. Electrical tree emanates from the end of the needle where the electric stress reaches the dielectric strength of the dielectric material. The potential distribution is determined at every step due to the boundary changes according to tree advancement by resolving Laplace's equation. The effect of the applied voltage levels on the formation of the electrical tree is investigated. The obtained results are in agreement with the available experimental data and published technical literature.

PL

W tym badaniu przedstawiamy propagację drzewa elektrycznego w izolacji stałej poprzez dynamiczną symulację z automatami komórkowymi. Pobranie próbki dielektryka XLPE umieszczonego między dwiema elektrodami pod napięciem stałym. Drzewo elektryczne emanuje z końca igły, gdzie naprężenie elektryczne osiąga wytrzymałość dielektryczną materiału dielektrycznego. Rozkład potencjału jest określany na każdym kroku ze względu na zmiany granic w zależności od postępu drzewa poprzez rozwiązanie równania Laplace'a. Zbadano wpływ przyłożonych poziomów napięcia

6

Mathematical modelling of gas nitriding process of steel using cellular automata

Ratajski J., Mydłowska K.

Journal of Achievements in Materials and Manufacturing Engineering

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2024

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Vol. 126, nr 2

58--65

EN

Purpose: The primary aim of this research was to develop a mathematical and computational model of the nitriding process for steel using CA cellular automata theory, which enables the modelling of spatial hardness distributions and nitrogen concentrations within the material. Design/methodology/approach: The proposed mathematical model consists of two interacting cellular automata: one representing the surface layer of the nitride material and the other describing the spatial distribution of nitrogen. The developed algorithm and model based on CA were implemented in the MATLAB environment, enabling more effective and efficient testing of the created model and its further use. Findings: The developed computer model enabled, by changing the values of the CA model parameters, which correspond to the nitrogen diffusion coefficient in alloy steel, nitrogen solubility in iron and the enthalpy of formation and decomposition of iron nitrides, to adapt the model to the description of the nitriding process of 1.2343 (WCL) steel. The model was experimentally verified by comparing predicted hardness profiles with those measured after nitriding. Research limitations/implications: The main limitation of the developed model is the size of the material fragment in which the nitriding process is simulated. Practical implications: High compliance of the results of numerical calculations with the results obtained by experimental measurements was obtained, which predestines the potential usage of CA-based models for scientific and practical applications. The model can be used as part of an optimisation procedure for designing hybrid composite layers for tribological applications, comprising a nitride layer and a coating deposited via Physical Vapor Deposition (PVD) techniques. Originality/value: The added value of the developed model of the nitriding process, based on the concept of CA, is the author’s modification of the transition rules (both for cells in the Moore and von Neumann neighbourhood) in the automaton related to the structural and phase transformations in the nitride material.

7

Forecasting Land Use and Land Cover Changes in the Malaprabha Right Bank Canal Command Area through Cellular Automata and Markov Chain Modeling

Madhusudhan M.S., Shivapur A.V., Surendra J.H.

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 6

54--65

EN

To formulate an effective growth management plan, it is imperative to comprehend the dynamic changes that transpire. This study focused on identifying such shifts spanning four decades, from 1990 to 2020, and utilized a GIS-integrated approach, employing cellular automata Markov chain model within TerrSet software for the MRBC area, to predict land use and land cover (LULC) for 2030. The accuracy evaluation of the classification method yielded overall accuracy percentages of 94.11%, 94.11%, 90.19%, and 94.12% for 1990, 2000, 2010, and 2020, respectively, accompanied by Kappa values of 0.921, 0.921, 0.895 and 0.922. The LULC map for 2020 was forecasted and compared to the actual map for validation, revealing a discrepancy of less than 5% in class distribution. The study findings indicated a 12.32% reduction in agricultural land (151.7 km2) compared to the 1990 LULC map in the projected 2030 map. In this future scenario, the converted region is allocated to urban and barren land classes. Consequently, decision-makers are urged to take necessary measures to preserve agricultural land from conversion, ensuring the enduring sustainability of agriculture.

8

Built-Up Development Prediction Based on Cellular Automata Modelling Around New Yogyakarta International Airport

Sidiq Wahid Akhsin Budi Nur, Fariz Trida Ridho, Saputro Purnomo Adi, Sholeh Muh

Ecological Engineering & Environmental Technology

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2024

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Vol. 25, iss. 1

238--250

EN

New Yogyakarta International Airport (NYIA) in Kulon Progo Regency was developed with the primary objective of fostering economic growth. The initiation of operations at NYIA in March 2020 triggered substantial urban development in the surrounding area. This research aimed to monitor the changes in land cover and predict the development of urban areas. The research methodology comprised the use of Random Forest, Classification, and Regression Tree machine learning algorithms to create land cover maps. It also incorporated Cellular Automata (CA), which was used to make prediction related to land development. The results showed that the land cover map had an overall accuracy level of above 0.80. Furthermore, it was observed from the results of the time series land cover analysis that there was a rapid growth in built-up lands. Between 2013 and 2017, these lands expanded by 572.38 hectares and further increased by 268.97 hectares from 2017 to 2023, leading to the conversion of 571.64 hectares of agricultural lands. On the basis of these findings, it was projected that by 2033, there would be an expansion of 386.08 hectares in built-up lands, with approximately 356.82 hectares converted from agricultural areas. The accuracy assessment of the 2023 land cover prediction map showed a high level of correctness, with a 97% accuracy rate. On the basis of these results, it was concluded that land conversion is essential to prevent environmental degradation, and further research can be carried out with the aim of assessing environmental quality indices.

9

Self-stabilisation of Cellular Automata on Tilings

Fatès Nazima, Marcovici Irèneb, Taati Siamak

Fundamenta Informaticae

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2022

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Vol. 185, nr 1

27--82

EN

Given a finite set of local constraints, we seek a cellular automaton (i.e., a local and uniform algorithm) that self-stabilises on the configurations that satisfy these constraints. More precisely, starting from a finite perturbation of a valid configuration, the cellular automaton must eventually fall back into the space of valid configurations where it remains still. We allow the cellular automaton to use extra symbols, but in that case, the extra symbols can also appear in the initial finite perturbation. For several classes of local constraints (e.g., k-colourings with k ≠ 3, and North-East deterministic constraints), we provide efficient self-stabilising cellular automata with or without additional symbols that wash out finite perturbations in linear or quadratic time, but also show that there are examples of local constraints for which the self-stabilisation problem is inherently hard. We note that the optimal self-stabilisation speed is the same for all local constraints that are isomorphic to one another. We also consider probabilistic cellular automata rules and show that in some cases, the use of randomness simplifies the problem. In the deterministic case, we show that if finite perturbations are corrected in linear time, then the cellular automaton self-stabilises even starting from a random perturbation of a valid configuration, that is, when errors in the initial configuration occur independently with a sufficiently low density.

10

Modeling of the Kinetics of Carbonitrides Precipitation Process and Simulate the Image of Microstructure Using Cellular Automata Method in Microalloyed Steels

Marynowski Przemysław, Hojny Marcin

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 3

1117--1124

EN

Microalloying elements such as Ti, Nb, V, entered into steel they influence their microstructure and mechanical properties, because formation of carbonitrides, M(C, N). Influence of carbonitrides to the microstructure and mechanical properties depends on their basic stereological parameters: volume fraction, Vv, and their size, r. In this work the Cellular Automata model of the kinetics of the carbonitrides precipitation which enable to predict the image of the microstructure and calculate the size of carbonitrides formed during isothermal annealing of supersaturated steel is presented. In the high temperature the microalloying elements inhibit the austenite grains growth. Chemical composition of steel has influence to volume fraction and size of precipitations. The work is supplemented with examples of experimental comparison.

11

Optimal steganographic method based on image encryption

Al-Bdour Nashat, Mansour Ayman M.

Przegląd Elektrotechniczny

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2021

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R. 97, nr 6

10--14

EN

The paper investigates an image encryption method for the implementation of steganographic information protection. This paper aims to increase the volume of a secret message with fixed sized image. The proposed system represents an image in the form of a binary code. Each pixel code consists of 24 bits, which encode blue, green and red colors. The resulting image code is encrypted using a key set of encrypt codes generated by a pseudo-random number generator. The generation is based on cellular automata with active cells. As a result, the best bits in the color bytes of each pixel have been identified. The method provides a high degree of encryption due to the fact that, in addition to encrypting the selected bits of the pixel codes, the codes are changed due to the introduction of the bits of the secret message. The bits of the secret message have a random order since the secret message is determined by its internal content. Each new message is different from other messages and is additionally encrypted. This makes it possible to use several encrypt keys in conceal a message in an image.

PL

W artykule omówiono metodę szyfrowania obrazu w celu realizacji steganograficznej ochrony informacji. Ten artykuł ma na celu zwiększenie objętości tajnej wiadomości z obrazem o stałym rozmiarze. Proponowany system przedstawia obraz w postaci kodu binarnego. Każdy kod piksela składa się z 24 bitów, które kodują kolory niebieski, zielony i czerwony. Wynikowy kod obrazu jest szyfrowany przy użyciu zestawu kluczy szyfrujących kodów generowanych przez generator liczb pseudolosowych. Generacja oparta jest na automatach komórkowych z aktywnymi komórkami. W rezultacie zidentyfikowano najlepsze bity w bajtach koloru każdego piksela. Metoda zapewnia wysoki stopień szyfrowania dzięki temu, że oprócz szyfrowania wybranych bitów kodów pikselowych, kody ulegają zmianie w wyniku wprowadzenia bitów tajnej wiadomości.

12

Capturing local material heterogeneities in numerical modelling of microstructure evolution

Madej Lukasz, Sitko Mateusz, Fular Aleksander, Sarzyn Rafal, Werminski Mariusz, Perzynski Konrad

Journal of Machine Engineering

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2021

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Vol. 21, No. 4

29--48

EN

The work focuses on developing the complex digital shadow of the metallic material microstructure that can predict its evolution during metal forming operations. Therefore, such a digital shadow has to consider all major physical mechanisms influencing the particular investigated phenomenon. The motivation for the work is directly related to the development of modern metallic materials, often of multiphase nature. Such microstructure types lead to local heterogeneities influencing material behaviour and eventually macroscopic properties of the final product. The concept of the digital material shadow, stages of the model development, and examples of practical applications to simulation of microstructure evolution are presented within the work. Capturing local heterogeneities that have a physical origin and eliminating numerical artefacts is particularly addressed. Obtained results demonstrate the capabilities of such a digital microstructure shadow approach in the numerical design of final product properties.

13

Segmentation of aggregate and asphalt in photographic images of pavements

Mejía Angela Marcela, Alzate Marco Aurelio, Reyes-Ortiz Oscar Javier

Engineering Transactions

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2021

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Vol. 69, iss. 1

19--42

EN

Particle size distribution of aggregate in asphalt pavements is used for determining important characteristics like stiffness, durability, fatigue resistance, etc. Unfortunately, measuring this distribution requires a sieving process that cannot be done directly on the already mixed pavement. The use of digital image processing could facilitate this measurement, for which it is important to classify aggregate from asphalt in the image. This classification is difficult even for humans and much more for classical image segmentation algorithms. In this paper, an expert committee approach was used, including classical adaptive Otsu, k-means vector quantization over a set of 8 principal components obtained from 26 features, and a Gaussian mixture model whose parameters are estimated through the expectation-maximization algorithm. A novel cellular automata approach is used to coordinate these expert opinions. Finally, a simple heuristic is used to reduce sub- and over-segmentation. The segmentation results are comparable to those obtained by a human expert, while the sieve size of the segmented images corresponds very well with that obtained from the sieving process, validating the proposed method of segmentation. The results show that with the digital imaging procedure it was possible to detect particles with a size of 100 m with 90% of success with respect to time-consuming manual techniques. In addition, with these results it is possible to establish the homogeneity of the sample and the distribution of the particles within the asphalt mixture.

14

Experimental and modelling study of the grain refinement of Fe-30wt%Ni-Nb austenite model alloy subjected to severe plastic deformation process

Svyetlichnyy D. S., Majta J., Kuziak R., Muszka K.

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 1

339--352

EN

This study addresses some aspects regarding a computer modelling based on three-dimensional Frontal Cellular Automata (FCA) for the simulation of ultrafine-grained (UFG) microstructure development in purpose-designed microalloyed austenite model alloy i.e. FCC structure. Proposed in the present study model is a step forward towards understanding the deformation and microstructure development mechanisms occurring during severe plastic deformation (SPD) processes with high accumulation of the plastic deformation effects in FCC structures. The analysed microalloyed austenite microstructures were developed due to SPD effects. Using the proposed computer model, based on three-dimensional FCA it has been shown that it is possible to predict some characteristics of the FCC microstructures such as the grain size and the distribution of the boundaries misorientation angle. These abilities were proved by the qualitative and quantitative comparisons of the modelling and SEM/EBSD results. The capabilities of the proposed model were tested using experimental results of the wire drawing processes. The paper presents the new original results of experimental studies of multi-staged MaxStrain technology with the microscopic investigation. Basing on data obtained from these studies, the dependencies of the evolution of grain structure and misorientation angle on the accumulative strain and cycle number were obtained in a form of approximation equations. The equations were implemented into the CA model, and MaxStrain technology was simulated. Comparison of the results obtained in experimental studies and simulations shows a satisfactory agreement. Industrial verification of the developed model as well shows a satisfactory agreement.

15

Cellular Automata-based computational library for development of digital material representation models of heterogenous microstructures

Boguń Konrad, Sitko Mateusz, Mojżeszko Mateusz, Madej Łukasz

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

335--349

EN

The development of an efficient numerical approach for the generation of a wide range of heterogeneous microstructures models with the application of the lean workflow concept is presented in the paper. First, the idea and implementation details of the developed cellular automata-based computational library allowing the development of digital material representation models within a workflow are presented in the paper. Such an approach provides the desired flexibility in the generation of various digital models of heterogenous microstructures. Therefore, the proposed library is mostly implemented within the object-oriented C + + programming language with the assumption of modularity. In this case, the main part of the application consists of classes and methods, which can be treated like base elements to be inherited and extended in other libraries. Each additional dynamic link library implements particular algorithms for the generation of specific microstructure features in the digital model within the unified data structures that allow the application of the workflow concept. The set of developed libraries and their assumptions are described as case studies to show the capabilities of the presented solution. Finally, examples of practical applications of the developed library in the full-field numerical simulations of complex material deformation are presented at the end of the paper.

16

Study of phase transformations in complex phase steel using a mesoscale cellular automaton model Part 1: Modeling fundamentals

Opara Jarosław, Kuziak Roman

Journal of Metallic Materials

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2020

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Vol. 72, no. 3

17--31

EN

A two-dimensional mesoscale model based on the concept of hybrid cellular automata is developed to study phase transformations in a complex phase steel during continuous cooling. The model is capable of simulating microstructure evolution with carbon diffusion in the volume and along grain boundaries, γ/α interfaces migration into austenite, as well as formation of bainite and martensite islands during intensive cooling in lower temperatures. In contrast to the classic statistical approaches which are based on the assumption of modeling one point in the material with homogeneous microstructure, the proposed phase transformations’ model in the mesoscale accounts for material heterogeneity. The simulation results in the form of a digital material representation with microstructures and maps showing the carbon concentration field as well as microhardness distribution are presented. One of the main advantages of the model is that has only seven adjustment coefficients that are used in the fitting process.

PL

Dwuwymiarowy mezoskalowy model oparty na koncepcji hybrydowych automatów komórkowych został opracowany w celu badania przemian fazowych w stali wielofazowej podczas ciągłego chłodzenia. Model umożliwia symulację rozwoju mikrostruktury wraz z dyfuzją węgla w objętości, jak i wzdłuż granic ziaren oraz migracją powierzchni międzyfazowych γ/α do austenitu, a także powstawaniem wysp bainitu i martenzytu podczas intensywnego chłodzenia w niższych temperaturach. W odróżnieniu od klasycznych podejść statystycznych, które bazują na założeniu modelowania jednego punktu w materiale o jednorodnej mikrostrukturze, zaproponowany model przemian fazowych w mezoskali umożliwia uwzględnienie warunków niejednorodności materiału. Zaprezentowano wyniki symulacji w postaci cyfrowej reprezentacji materiału z mikrostrukturami oraz mapami przedstawiającymi pola stężenia węgla oraz rozkłady mikrotwardości. Jedną z głównych zalet modelu jest to, że regulowany jest tylko za pomocą siedmiu współczynników w procesie dopasowania.

17

Study of phase transformations in complex phase steel using a mesoscale cellular automaton model part 2: Experiments and validation

Opara Jarosław, Kuziak Roman

Journal of Metallic Materials

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2020

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Vol. 72, no. 3

32--44

EN

A two-dimensional mesoscale model based on the concept of hybrid cellular automata was used to study phase transformations in a complex phase steel during continuous cooling. This model enables simulation of the decomposition of austenite into ferrite, bainite, and martensite, accompanied by calculations of volume and grain boundary diffusion of carbon. In effect, as a result, one can observe the morphology of simulated microstructures, corresponding carbon segregation as well as microhardness distribution. These results with the kinetics of austenite to ferrite phase transformation and predicted values of the complex phase steel hardness are the subject of model validation. A series of dilatometric experiments were carried out with constant cooling rates in order to construct a CCT diagram and validate the presented model. The convergence of simulated results with empirical outcomes was confirmed quantitatively using a dedicated goal function and data summaries in the table and graphs. However, some qualitative and quantitative discrepancies in terms of microstructure morphology are indicated which was possible thanks to applying a wide range of different validation parameters of the model. It is emphasized how crucial is the use of appropriate validation methodology.

PL

Dwuwymiarowy mezoskalowy model oparty na koncepcji hybrydowych automatów komórkowych zastosowano do badania przemian fazowych w stali wielofazowej podczas ciągłego chłodzenia. Model ten umożliwia symulację rozpadu austenitu w ferryt, bainit i martenzyt wraz z obliczeniami objętościowej i granicznej dyfuzji węgla. W efekcie można zaobserwować morfologię symulowanych mikrostruktur, odpowiadającą im segregację węgla, a także rozkład mikrotwardości. Wyniki te wraz z kinetyką ferrytycznej przemiany fazowej i przewidywanymi wartościami twardości stali wielofazowej są przedmiotem walidacji modelu. Przeprowadzono szereg eksperymentów dylatometrycznych przy stałych szybkościach chłodzenia w celu opracowania wykresu CTPc i walidacji przedstawionego modelu. Zbieżność wyników symulacji z danymi empirycznymi została potwierdzona ilościowo za pomocą dedykowanej funkcji celu oraz zestawienia danych w tabeli i na wykresach. Jednakże, wskazano na pewne rozbieżności jakościowe i ilościowe pod względem morfologii mikrostruktury, co było możliwe dzięki zastosowaniu szerokiego wachlarza różnych parametrów do walidacji modelu. Podkreślono, jak istotne jest zastosowanie odpowiedniej metodologii walidacji.

18

Unveiling the Hidden Dimension of Pedestrian Crowds : Introducing Personal Space and Crowding into Simulations

Bandini Stefania, Crociani Luca, Gorrini Andrea, Nishinari Katsuhiro, Vizzari Giuseppe

Fundamenta Informaticae

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2020

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Vol. 171, nr 1-4

19--38

EN

Models for the automated analysis and simulation of the complex phenomena observable in built environment crowded by pedestrians have been studied for over thirty years. Nonetheless, one of the commonly agreed upon rules guiding regulation of distance among pedestrian, i.e. proxemics, was defined and discussed in static settings, whereas scenarios of interest generally deal with individual and collective movements in crowds. The present paper presents a systemic perspective on the research aimed at defining a dynamic form of proxemics. The paper firstly reports the results of an experiment focused on proxemics and pedestrians personal space, as the hidden dimension of human spatial behavior in crowded environments. We propose a representation of personal space through discrete potentials and an innovative crowding estimation method (i.e. Cumulative Mean Crowding), going beyond simple perceived density evaluation. The experimental setting is introduced and applied to appraise the potential impact of this novel pedestrian perception mechanism on innovative simulation models.

19

On Expansivity and Pseudo-Orbit Tracing Property for Cellular Automata

Jalonen Joonatan, Kari Jarkko

Fundamenta Informaticae

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2020

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Vol. 171, nr 1-4

239--259

EN

Ultimate expansivity extends concepts of expansivity and positive expansivity. We consider one-sided variants of ultimate expansivity and pseudo-orbit tracing property (also known as the shadowing property) for surjective one-dimensional cellular automata. We show that ultimately right (or left) expansive surjective cellular automata are chain-transitive; this improves a result by Boyle that expansive reversible cellular automata are chain-transitive. We then use this to show that left-sided pseudo-orbit tracing property and right-sided ultimate expansivity together imply pseudo-orbit tracing property for surjective cellular automata. This reproves some known results, most notably some of Nasu’s. Our result improves Nasu’s result by dropping an assumption of chain-recurrence, however, we remark that this improvement can also be achieved using the Poincaré recurrence theorem. The pseudo-orbit tracing property implies that the trace subshifts of the cellular automaton are sofic shifts. We end by mentioning that among reversible cellular automata over full shifts we have examples of right expansive cellular automata with non-sofic traces, as well as examples of cellular automata with left pseudo-orbit tracing property but non-sofic traces, illustrating that neither assumption can be dropped from the theorem mentioned above. This paper is a generalized and improved version of a conference paper presented in AUTOMATA 2018.

20

Sphere packing algorithm for the generation of digital models of polycrystalline microstructures with heterogeneous grain sizes

Hajder Lucyna, Madej Łukasz

Computer Methods in Materials Science

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2020

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Vol. 20, No. 1

22--30

EN

Development of the cellular automata (CA) sphere packing algorithm dedicated to the generation of two- and three-dimensional digital, synthetic microstructure models with heterogenous grain size distribution is presented within the paper. The synthetic microstructure model is generated in four major steps: generation of 2D/3D cellular automata computational domain, generation of circles/spheres with a required size distribution, close-packed filling of the computational domain with generated circles/spheres, growth of the circles/spheres according to the unconstrained CA growth algorithm. As a result, synthetic microstructure models with specific, required grain size distribution described by e.g. uni- or bimodal one are obtained. To reduce computational complexity and decrease execution time, the rotation of the circles/spheres during the packing stage is based on the vector accounting for the distance from computational domain borders and other spheres. The CA grain growth algorithm is also implemented using threads mechanism allowing parallel execution of computations to increase its efficiency. The developed algorithm with the implementation details as well as a set of examples of obtained results are presented within the paper.

PL

W pracy przedstawiono opracowanie algorytmu pakowania sferycznego automatu komórkowego (CA) dedykowanego do generowania dwu- i trójwymiarowych, cyfrowych, syntetycznych modeli mikrostruktury o niejednorodnym rozkładzie ziarnistości. Syntetyczny model mikrostruktury jest generowany w czterech głównych etapach: generowanie domeny obliczeniowej automatu komórkowego 2D/3D, generowanie okręgów/kul o wymaganym rozkładzie wielkości, wypełnianie domeny obliczeniowej wygenerowanymi okręgami/kulami, wzrost okręgów/kul zgodnie z algorytmem nieograniczonego wzrostu CA. W rezultacie otrzymujemy syntetyczne modele mikrostruktury o specyficznym, wymaganym rozkładzie uziarnienia opisanym np. jedno- lub dwumodalnym rozkładem. Aby zmniejszyć złożoność obliczeniową i skrócić czas wykonania, rotacja kół/kul podczas etapu pakowania opiera się na wektorowym rozliczaniu odległości od granic domen obliczeniowych z innymi sferami. Algorytm wzrostu ziarna CA jest również zaimplementowany z wykorzystaniem mechanizmu wątków, co pozwala na równoległe wykonywanie obliczeń w celu zwiększenia jego wydajności. W artykule przedstawiono opracowany algorytm wraz ze szczegółami implementacji oraz zestawem przykładów uzyskanych wyników.