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1

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.

2

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.

3

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.

4

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.

5

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.

6

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.

7

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.

8

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.

9

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.

10

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.

11

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.

12

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.

13

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.

14

Improving the effectivity of urban freight transport by means of cellular automata simulations

Kijewska K., Małecki K.

Archives of Transport System Telematics

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2020

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Vol. 13, iss. 1

20--25

EN

Unloading bays are one of the most popular and simple to implement solutions to support development of sustainable urban freight transport systems. The solution is aimed at reducing congestion on busy city streets, which is often caused by freight vehicles that, in an attempt to load or unload their cargoes, park directly in traffic lanes. Where dedicated unloading bays are in place, the traffic is undisturbed, which helps to prevent extra consumption of energy and fuel, and thus extra pollution, and which also makes it possible to avoid wasting time in traffic jams and ensuing costs. Therefore, the major benefit derived from this solution is its contribution to reduction of traffic congestion, followed by a perceptible decrease in pollutant emissions. This article aims at developing an algorithm for recommended distribution of unloading bays based on the reported locations of delivery points and parameters related to varied quantities of goods and the number of available parking spaces in the vicinity of unloading bays. Additionally, it addresses the issue of using unloading bays as EV charging stations. The proposed solution was implemented on the basis of a dedicated road traffic simulator based on the original cellular automaton model..

15

Application of modified Ritchie-Knott-Rice criterion to cellular automata

Janus-Gałkiewicz Urszula, Neimitz Andrzej

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 3

577--590

EN

In this paper, the cellular automata model is applied to analyse cleavage and ductile fracture in front of a crack in three-point-bend specimens made of Hardox-400 steel. The research programme was composed of experiments followed by fractographic and numerical analyses. On the basis of microscopic observations, the sizes of cells used in the automata were determined. The algorithm enabled mapping of the two-dimensional crack surface as well as a simulation of temperature-dependent failure mechanisms by defining transition rules based on the modified Ritchie-Knott-Rice cleavage fracture criterion. The critical stress values were estimated and verified by the cellular automata model.

16

Improving Image Sharpness by Surface Recognition

Zerbino D.

ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes

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2019

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Vol. 8, No 2

39--44

EN

The article proposes a rule for improving image sharpness and analyzes its implementation by means of the cellular automata formalism and neural networks. It has been proved, that the previously known contrasting algorithm, which uses a template and 3x3 pixels, can be improved considerably by repeatedly applying the iterative process over templates 2x2 with the rule "anti - blur" ( C 11 = C 11 x F - ( C 12 + C 21 + C 22) x S ) and gradient color correction at each step after the "anti - blur". Colors of images in the template are presented as real numbers (R, G, B). To correct the gradient (C11 < C12, C11 < C21, C11

17

Cellular-automata based modeling of heterogeneous biofilm growth for microbiological processes with various kinetic models

Skoneczny Szymon

Chemical and Process Engineering

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2019

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Vol. 40, nr 2

145–-155

EN

The study concerns modeling and simulation of the growth of biofilms with heterogeneous structureswith a discrete mathematical model based on theory of cellular automata. The article presents two-dimensional density distributions of biofilms for microbial processes: oxidation of ammonium byNitrosomonas europaeabacteria and glucose utilization byPseudomonas aeruginosabacteria. Theinfluence of limiting substrate concentration in the liquid phase on biofilm structure was determined.It has been shown that the value of death rate coefficient of microorganisms has the qualitative andquantitative influence on the density and porosity of the biofilm.

18

Detection of Modic changes in MR images of spine using local binary patterns

Athertya Jiyo S., Saravana Kumar Gurunathan, Govindaraj Jayaraj

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 1

17--29

EN

Background and objective: With increase in prevalence of lower back pain, fast and reliable computer aided methods for clinical diagnosis associated with the same is needed for improving the healthcare reach. The magnetic resonance images exhibit a change in signal intensity on the vertebral body close to end plates, which are termed as Modic changes (MC), and are known to be clear indicators of lower back pain. The current work deals with computer aided methods for automating the classification of signal changes between normal and degenerate cases so as to aid physicians in precise and suitable diagnosis for the ailment. Methods: In order to detect Modic changes in vertebrae, initially the vertebrae are segmented from sagittal MR T1 and T2 imaged using a semi automatic cellular automata based segmentation. This is followed by textural feature extraction using Local Binary Patterns (LBP) and its variants. Various classifiers based on machine learning approaches using Random Forest, kNN, Bayes and SVM were evaluated for its classification performance. Since medical image dataset in general have bias towards healthy and diseased state, data augmentation techniques were also employed. Results: The implemented method is tested and validated over a dataset containing 100 patients. The proposed framework achieves an accuracy of 81% and 91.7% with and without augmentation of data respectively. A comparative study with the state of art methods reported in literature shows that the method proposed in better in terms of computational cost without any compromise on classification accuracy. Conclusion: A novel approach to identify MC in vertebrae by exploiting textural features is proposed. This shall assist radiologists in detecting abnormalities and in treatment planning.

19

Cellular particle swarm optimization with a simple adaptive local search strategy for the permutation flow shop scheduling problem

Seck-Tuoh-Mora Juan C., Medina-Marin Joselito, Martinez-Gomez Erick S., Hernandez-Gress Eva S., Hernandez-Romero Norberto, Volpi-Leon Valeria

Archives of Control Sciences

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2019

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Vol. 29, No. 2

205--226

EN

Permutation flow shop scheduling problem deals with the production planning of a number of jobs processed by a set of machines in the same order. Several metaheuristics have been proposed for minimizing the makespan of this problem. Taking as basis the previous Alternate Two-Phase PSO (ATPPSO) method and the neighborhood concepts of the Cellular PSO algorithm proposed for continuous problems, this paper proposes the improvement of ATPPSO with a simple adaptive local search strategy (called CAPSO-SALS) to enhance its performance. CAPSO-SALS keeps the simplicity of ATPPSO and boosts the local search based on a neighborhood for every solution. Neighbors are produced by interchanges or insertions of jobs which are selected by a linear roulette scheme depending of the makespan of the best personal positions. The performance of CAPSO-SALS is evaluated using the 12 different sets of Taillard’s benchmark problems and then is contrasted with the original and another previous enhancement of the ATPPSO algorithm. Finally, CAPSO-SALS is compared as well with other ten classic and state-of-art metaheuristics, obtaining satisfactory results.

20

Cellular automata for simulation of dendritic growth with surface active refractory inoculants

Yermolenko D. Yu., Holovko V. V., Stepanuyk S. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2018

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Vol. 88, nr 2

49--54

EN

Purpose: During weld metal structure formation the possibility of impact on its mechanical properties are much more limited in comparison with metallurgy and technology of steel production. Adding of the inoculants to the welding pool is one of the promising methods of influencing the structure and mechanical properties of the weld metal. Design/methodology/approach: Cellular automata (CA) with additions of finite difference method (FDM) is one of the best ways to simulate dendritic growth process with the surfaceactive inoculants. It`s easy to add new rules of interaction between the inoculants and dendrite surface to the cellular automata model. Findings: It was found that average distance between primary dendrites axis decrease with increase of the inoculants wetting angle by melt iron. Obtained results were confirmed experimentally on weld metal samples that were obtained by the welding of HSLA steels with the surface-active inoculants. Research limitations/implications: The inoculants with size that comparable with cells size of the model (≈0.4 microns) were distributed evenly in computational area. Practical implications: Adding of surface-active inoculants to the melt metal improve structure and mechanical properties of weld metal. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) can be used. Originality/value: Refractory inoculants adding to the melt metal are wide used in metallurgy as crystallization centers and heat absorbers. Inoculants that were added to the welding pool of high-strength low-alloyed (HSLA) steel welds could also influence on crystallization processes of weld metal as surface active particles. In the contact point between the dendrite surface and the surface-active inoculant, a surface energy is change depending of the inoculant surface properties. Different refractory particles (TiC, TiN, SiC, TiO2, Al2O3 and ZrO2) were used.