1. An algorithm for voxelised solids representation using chain codesBlaž Repnik, Libor Váša, Borut Žalik, 2025, original scientific article Abstract: The paper introduces a new method to describe the surfaces of voxelised solids. It operates in three stages: a hierarchical linked list of chain code sequences is created first; the linked lists are pruned; and, finally, the content of the data structure is stored. The method uses chain codes from either a three- or nine-symbols alphabet. In the first case, two chain code symbols are needed to access the next face, while, in the second case, this is done by one symbol. The pair of chain codes from the three-symbols alphabet, or the individual symbol from the nine-symbols alphabet are considered as tokens. The sets of tokens are, in both cases, extended by two tokens, indicating the beginning and ending of the list. The method processes solids of any shape, including those containing holes, cavities, or multiple components existing in the same voxel space. Edge-connectivity is permitted. The method was compared against the method proposed by Lemus et al., which is designed for solids without holes. Although supporting a broader set of voxelised solids, the proposed method generates sequences of tokens that are, on average, up to 10% shorter. Since the information entropy of the sequences of tokens produced by the proposed method is also smaller, the obtained sequences are more compressible, as confirmed by applying gzip and bzip2 data compressors.
Keywords: voxels, chain code, data structures, pruning, information entropy, data compression
Published in DKUM: 19.05.2025; Views: 0; Downloads: 1
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2. Cast microstructure of a complex concentrated noble alloy ▫$Ag_{20}Pd_{20}Pt_{20}Cu_{20}Ni_{20}▫$Lidija Simić, Rebeka Rudolf, Peter Majerič, Ivan Anžel, 2022, original scientific article Abstract: A complex concentrated noble alloy (CCNA) of equiatomic composition (Ag20Pd20Pt20Cu20Ni20
–20 at. %) was studied as a potential high—performance material. The equiatomic composition
was used so that this alloy could be classified in the subgroup of high—entropy alloys (HEA). The
alloy was prepared by induction melting at atmospheric pressure, using high purity elements. The
degree of metastability of the cast state was estimated on the basis of changes in the microstructure
during annealing at high temperatures in a protective atmosphere of argon. Characterisation of the
metallographically prepared samples was performed using a scanning electron microscope (SEM)
equipped with an energy dispersive spectrometer (EDS), differential scanning calorimetry (DSC),
and X–ray diffraction (XRD). Observation shows that the microstructure of the CCNA is in a very
metastable state and multiphase, consisting of a continuous base of dendritic solidification—a matrix
with an interdendritic region without other microstructural components and complex spheres. A
model of the probable flow of metastable solidification of the studied alloy was proposed, based on
the separation of L—melts into L1
(rich in Ni) and L2
(rich in Ag). The phenomenon of liquid phase
separation in the considered CCNA is based on the monotectic reaction in the Ag−Ni system.
Keywords: complex concentrated noble alloy, high—entropy alloy, metastability
Published in DKUM: 20.03.2025; Views: 0; Downloads: 7
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3. Enzyme cascade to enzyme complex phase-transition-like transformation studied by the maximum entropy production principleAndrej Dobovišek, Tina Blaževič, Samo Kralj, Aleš Fajmut, 2025, original scientific article Abstract: In biological cells, soluble enzymes often spontaneously reorganize into higher-order complexes called metabolons, providing regulatory advantages over individual soluble enzymes under specific conditions. Despite their importance, the mechanisms underlying metabolon formation remain unclear. Here we report a theoretical model that elucidates the spontaneous transition between soluble enzyme cascades and complexes, driven by fluctuations in intermediate metabolite concentrations. The model integrates the maximum entropy production principle (MEPP) and the Shannon information entropy (MaxEnt), Landau phase-transition theory, kinetic modeling, stability analysis, and metabolic control analysis. Our results show that soluble enzymes and enzyme complexes represent two distinct catalytic states with unique kinetic and regulatory properties. The transition from an enzyme cascade to an enzyme complex displays features of a first-order phasetransition, highlighting the system's tendency to reorganize into its most thermodynamically favorable state, providing a potential pathway for metabolic regulation.
Keywords: theoretical modeling, irreversible thermodynamics, maximum entropy production principle, Shannon information entropy, first-order phase transition, enzyme organization, enzyme cascade, enzyme complex
Published in DKUM: 06.02.2025; Views: 0; Downloads: 2
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4. A case study on entropy-aware block-based linear transforms for lossless image compressionBorut Žalik, David Podgorelec, Ivana Kolingerová, Damjan Strnad, Štefan Kohek, 2024, original scientific article Abstract: Data compression algorithms tend to reduce information entropy, which is crucial, especially in the case of images, as they are data intensive. In this regard, lossless image data compression is especially challenging. Many popular lossless compression methods incorporate predictions and various types of pixel transformations, in order to reduce the information entropy of an image. In this paper, a block optimisation programming framework is introduced to support various experiments on raster images, divided into blocks of pixels. Eleven methods were implemented within , including prediction methods, string transformation methods, and inverse distance weighting, as a representative of interpolation methods. Thirty-two different greyscale raster images with varying resolutions and contents were used in the experiments. It was shown that reduces information entropy better than the popular JPEG LS and CALIC predictors. The additional information associated with each block in is then evaluated. It was confirmed that, despite this additional cost, the estimated size in bytes is smaller in comparison to the sizes achieved by the JPEG LS and CALIC predictors.
Keywords: computer science, information entropy, prediction, inverse distance transform, string transformations
Published in DKUM: 07.01.2025; Views: 0; Downloads: 9
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5. Beauty in artistic expressions through the eyes of networks and physicsMatjaž Perc, 2020, review article Abstract: Beauty is subjective, and as such it, of course, cannot be defined in absoluteterms. But we all know or feel when something is beautiful to us personally.And in such instances, methods of statistical physics and network sciencecan be used to quantify and to better understand what it is that evokesthat pleasant feeling, be it when reading a book or looking at a painting.Indeed, recent large-scale explorations of digital data have lifted the veilon many aspects of our artistic expressions that would remain foreverhidden in smaller samples. From the determination of complexity andentropy of art paintings to the creation of the flavour network and the prin-ciples of food pairing, fascinating research at the interface of art, physics andnetwork science abounds. We here review the existing literature, focusing inparticular on culinary, visual, musical and literary arts. We also touch uponcultural history and culturomics, as well as on the connections betweenphysics and the social sciences in general. The review shows that the syner-gies between these fields yield highly entertaining results that can oftenbe enjoyed by layman and experts alike. In addition to its wider appeal,the reviewed research also has many applications, ranging from improvedrecommendation to the detection of plagiarism.
Keywords: complexity, entropy, network science, data science, self-organization
Published in DKUM: 17.09.2024; Views: 0; Downloads: 414
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6. A new transformation technique for reducing information entropy : a case study on greyscale raster imagesBorut Žalik, Damjan Strnad, David Podgorelec, Ivana Kolingerová, Luka Lukač, Niko Lukač, Simon Kolmanič, Krista Rizman Žalik, Štefan Kohek, 2023, original scientific article Abstract: This paper proposes a new string transformation technique called Move with Interleaving (MwI). Four possible ways of rearranging 2D raster images into 1D sequences of values are applied, including scan-line, left-right, strip-based, and Hilbert arrangements. Experiments on 32 benchmark greyscale raster images of various resolutions demonstrated that the proposed transformation reduces information entropy to a similar extent as the combination of the Burrows–Wheeler transform followed by the Move-To-Front or the Inversion Frequencies. The proposed transformation MwI yields the best result among all the considered transformations when the Hilbert arrangement is applied.
Keywords: computer science, algorithm, string transformation, information entropy, Hilbert space filling curve
Published in DKUM: 22.05.2024; Views: 160; Downloads: 17
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7. Szeged-like entropies of graphsMatthias Dehmer, Frank Emmert-Streib, Niko Tratnik, Petra Žigert Pleteršek, 2022, original scientific article Keywords: Szeged entropy, Mostar entropy, PI entropy, cut method, quotient graphs, sensitivity of a topological descriptor
Published in DKUM: 20.05.2024; Views: 164; Downloads: 15
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8. Self-organization of enzyme-catalyzed reactions studied by the maximum entropy production principleAndrej Dobovišek, Marko Vitas, Tina Blaževič, Rene Markovič, Marko Marhl, Aleš Fajmut, 2023, original scientific article Abstract: The self-organization of open reaction systems is closely related to specific mechanisms that allow the export of internally generated entropy from systems to their environment. According to the second law of thermodynamics, systems with effective entropy export to the environment are better internally organized. Therefore, they are in thermodynamic states with low entropy. In this context, we study how self-organization in enzymatic reactions depends on their kinetic reaction mechanisms. Enzymatic reactions in an open system are considered to operate in a non-equilibrium steady state, which is achieved by satisfying the principle of maximum entropy production (MEPP). The latter is a general theoretical framework for our theoretical analysis. Detailed theoretical studies and comparisons of the linear irreversible kinetic schemes of an enzyme reaction in two and three states are performed. In both cases, in the optimal and statistically most probable thermodynamic steady state, a diffusion-limited flux is predicted by MEPP. Several thermodynamic quantities and enzymatic kinetic parameters, such as the entropy production rate, the Shannon information entropy, reaction stability, sensitivity, and specificity constants, are predicted. Our results show that the optimal enzyme performance may strongly depend on the number of reaction steps when linear reaction mechanisms are considered. Simple reaction mechanisms with a smaller number of intermediate reaction steps could be better organized internally and could allow fast and stable catalysis. These could be features of the evolutionary mechanisms of highly specialized enzymes.
Keywords: enzymes, kinetic data analysis, steady state, self-organization, maximum entropy production
Published in DKUM: 08.05.2024; Views: 234; Downloads: 11
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10. The maximum entropy production principle and linear irreversible processesPaško Županović, Domagoj Kuić, Željana Bonačić Lošić, Dražen Petrov, Davor Juretić, Milan Brumen, 2010, original scientific article Abstract: It is shown that Onsager’s principle of the least dissipation of energy is equivalent to the maximum entropy production principle. It is known that solutions of the linearized Boltzmann equation make extrema of entropy production. It is argued, in the case of stationary processes, that this extremum is a maximum rather than a minimum.
Keywords: entropy production, linear nonequilibrium thermodynamics, linearized Boltzmann equation
Published in DKUM: 21.06.2017; Views: 1249; Downloads: 408
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