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Publications - 6383

Enabling technology models with nonlinearities in the synthesis of wastewater treatment networks based on the P-graph framework

Ákos Orosz Kirti M. Yenkie Jean Pimentel Emmanuel A. Aboagye Mihály Csaba Markót Heriberto Cabezas Ferenc Friedler

Publication Name: Computers and Chemical Engineering

Publication Date: 2022-11-01

Volume: 167

Issue: Unknown

Page Range: Unknown

Description:

Designing effective wastewater treatment networks is challenging because of the large number of treatment options available for performing similar tasks. Each treatment option has variability in cost and contaminant removal efficiency. Moreover, their mathematical models are highly nonlinear, thus rendering them computationally intensive. Such systems yield mixed-integer nonlinear programming models which cannot be solved properly with contemporary optimization tools that may result in local optima or may fail to converge. Herein, the P-graph framework is employed, thus generating all potentially feasible process structures, which results in simpler, smaller mathematical models. All potentially feasible process networks are evaluated by nonlinear programming resulting in guaranteed global optimum; furthermore, the ranked list of the n-best networks is also available. With the proposed tool, better facilities can be designed handling complex waste streams with minimal cost and reasonable environmental impact. The novel method is illustrated with two case studies showing its computational effectiveness.

Open Access: Yes

DOI: 10.1016/j.compchemeng.2022.108034

Urban scaling of football followership on Twitter

Eszter Bokányi Attila Sóti Gábor Vattay

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2018-01-01

Volume: 15

Issue: 5

Page Range: 239-250

Description:

Social sciences have an important challenge today to take advantage of new research opportunities provided by large amounts of data generated by online social networks. Because of its marketing value, sports clubs are also motivated in creating and maintaining a stable audience in social media. In this paper, we analyze followers of prominent footballs clubs on Twitter by obtaining their home locations. We then measure how city size is connected to the number of followers using the theory of urban scaling. The results show that the scaling exponents of club followers depend on the income of a country. These findings could be used to understand the structure and potential growth areas of global football audiences.

Open Access: Yes

DOI: 10.12700/APH.15.5.2018.5.14

NFTs and Cryptocurrencies—The Metamorphosis of the Economy under the Sign of Blockchain: A Time Series Approach

Laszlo Vasa Constanta Mihaescu Simona Andreea Apostu Zbyslaw Dobrowolski Mirela Panait

Publication Name: Mathematics

Publication Date: 2022-09-01

Volume: 10

Issue: 17

Page Range: Unknown

Description:

Although NFTs (non-fungible tokens) and cryptocurrencies are active on the same market, their prices are not so closely related over time. The objective of this paper is to identify the relationship between the two types of assets (NFTs and the cryptocurrencies Ethereum, Crypto Coin, and Bitcoin), using data for the period between September 2020 until February 2022. The conclusions of the study are useful for cryptocurrency and NFT issuers, but also for investors on the financial market who are reconfiguring their portfolios with increasing frequency, and use these new assets for speculative or hedging purposes based on blockchain technology. The results highlighted relationships between NFTs and Ethereum, between Ethereum and Crypto Coin, and between Bitcoin and Ethereum, Ethereum being a bridge between all four. Therefore, NFTs present a relationship with Ethereum, the NFTs price had a causal effect on the price of Ethereum.

Open Access: Yes

DOI: 10.3390/math10173218

Open-source complex-geometry 3D fluid dynamics for applications with unpredictable heterogeneous dynamic high-performance-computing loads

József Bakosi

Publication Name: Computer Methods in Applied Mechanics and Engineering

Publication Date: 2024-01-05

Volume: 418

Issue: Unknown

Page Range: Unknown

Description:

We discuss the software implementation of a finite element method, intended for the simulation of complex-geometry 3D flows, using hardware resources effectively, including problems with a priori unknown, heterogeneous, and dynamic parallel computational load. Our fundamental choices of data structures, algorithm, and software design specifically target engineering resolution and accuracy requirements. Some of these choices are: unstructured grids (to explicitly resolve complex 3D geometries), tetrahedra-only computational elements (to enable automatic mesh generation), edge-based finite element scheme (to reduce indirect addressing for increased performance), distributed-memory parallel computing paradigm (to enable large problems), and Charm++ (https://charmplusplus.org) as the runtime system (to effectively use computing resources even in the presence of hardware heterogeneities and dynamic application requirements). We discuss aspects of the implementation that enable exercising unique features of the runtime system, e.g., the single Charm++ programming abstraction, overdecomposition, asynchronous execution, latency-hiding parallel communication and computation, task-parallelism, and dynamic load balancing via object migratability. Multiple test problems are used to verify and validate the numerical solutions and computational performance and scalability to high-performance computing environments are discussed. For maximum transparency and reproducibility, and to encourage future research, development, and use, the full source code, together with regression tests and documentation, is publicly available at https://xyst.cc.

Open Access: Yes

DOI: 10.1016/j.cma.2023.116586

Sensitivity calculation of LF RFID transponder coil by the mutual effective permeability method

Miklós Kuczmann Péter Csurgai

Publication Name: Pollack Periodica

Publication Date: 2011-08-01

Volume: 6

Issue: 2

Page Range: 3-12

Description:

Sensitivity is the most important parameter of the Transponder coils from the performance point of view. Due to the open magnetic circuit constructions analytic formulas are not available and not applicable to calculate the sensitivity. Analogically to the self-inductance effective permeability a similar effective permeability can be introduced for the mutual inductance, as well. The presented sensitivity calculation method is based on the mutual effective permeability. By the presented method, the sensitivity of inductors with arbitrary shape and permeability materials can be calculated with good accuracy.

Open Access: Yes

DOI: 10.1556/Pollack.6.2011.2.1

Optimization-based decision workflow for designing regional renewable energy systems

Botond Bertok Michael Eder Stephan Maier Jean Pimentel Bálint Filep Michael Narodoslawsky

Publication Name: Energy

Publication Date: 2026-09-01

Volume: 358

Issue: Unknown

Page Range: Unknown

Description:

The systematic planning of regional energy systems remains an issue of utmost importance for modern society. Thus, developing tools for effective design and communication with regional actors remains a relevant goal in research. This work presents an optimization-based decision workflow for regional energy planning aimed at enhancing stakeholder engagement and supporting informed decision-making during early design stages. Decision-making takes place within administrative units that exercise governmental functions through a top-down decentralization of responsibilities, often via federal structures. Within a given state, these units may include regions, counties, or political districts, as classified by the levels of the NUTS (Nomenclature of Territorial Units for Statistics) system. Consequently, within the decision-support process, stakeholders typically comprise the leaders of these administrative units, who possess substantive operational influence over the development of their respective entities. The proposed workflow integrates a rigorous optimization approach that permits the systematic generation of multiple solutions and the assessment of various scenarios for a given territory. The methodology is demonstrated through a case study in Carnica-Rosental, Austria, wherein four scenarios served as a platform for stakeholder dialogue and the development of integrated regional energy systems. The proposed workflow offers a powerful decision-support tool for systematic regional energy planning capable of providing insightful information about the region and serving as a platform for policymaking.

Open Access: Yes

DOI: 10.1016/j.energy.2026.141393

Data-driven decision-making framework for the evaluation of the traders in the stock market using cosine trigonometric single-valued neutrosophic approach

Dragan Pamucar Nasreen Kausar Murugan Palanikumar Vladimir Simic

Publication Name: Journal of Mathematics and Computer Science

Publication Date: 2026-01-01

Volume: 41

Issue: 2

Page Range: 222-243

Description:

The cosine trigonometric single valued neutrosophic number (CT-SVNN) is a suitable expansion of the standard neutrosophic number. Single-valued neutrosophic sets (SVNSs) may effectively overcome three components: degree of truth, indeterminacy, and falsity. In recent years, the aggregation operator (AO) and its applications have undergone development. This study introduces a few new AOs for multi-attribute decision-making (MADM). We introduce a novel approach for cosine trigonometric SVNS (CT-SVNS) and CT-SVNS with normal (CT-SVNNS), which are SVNS extensions. It is also required to discuss the CT-SVNNS method fundamental features in this communication, such as idempotency, boundedness, commutativity and monotonicity. There are numerous CT-SVNNS operators that have been proposed, including CT-SVN normal weighted averaging (CT-SVNNWA), CT-SVN normal weighted geometric (CT-SVNNWG), generalized CT-SVNNWA (GCT-SVNNWA) and generalized CT-SVNNWG. A powerful strategy for solving the MADM problem is provided that makes use of new developed generalized operators. Through a case study, the value of the suggested MADM approach is demonstrated. The new strategy is shown using a market share problem, and the outcomes are contrasted and examined against an existing method. This combination of generalized AO was rated successful based on expert preferences. As a result, a varied collection of experts may be accepted.

Open Access: Yes

DOI: 10.22436/jmcs.041.02.06

Slope stabilisation of railway embankments over loose subgrades using deep-mixed columns

Morteza Esmaeili Farshad Astaraki

Publication Name: Proceedings of the Institution of Civil Engineers Ground Improvement

Publication Date: 2022-12-01

Volume: 175

Issue: 4

Page Range: 247-260

Description:

An investigation was undertaken into the stability of railway embankment slopes over soft subgrades stabilised by deep-mixed columns (DMCs). Three 1:10 scale laboratory embankments were constructed over unreinforced and reinforced subgrade with DMCs in square and triangle patterns. The load-settlement responses of both embankments and columns were measured. The laboratory embankments were then mathematically modelled and the results were compared. After validation, a comprehensive parametric study was carried out to evaluate the factor of safety (FoS) of the embankment side slopes against sliding. Five embankment soil types from poor to high strength, three heights from 1.5 to 10 m and various DMC improvement area ratios from 0 to 65% were considered. The experimental outcomes indicated an increase of nearly 63% in the bearing capacity of both DMC-supported embankments compared with the unreinforced one. Regarding the parametric study, a minimum required FoS of 1.5 was observed for 1.5 m embankments of all soil types stabilised with a 60% improvement ratio. The greatest safety increase was associated with a 1.5 m height embankment with poor soil type, which showed a 36% increase.

Open Access: Yes

DOI: 10.1680/jgrim.20.00049

Failure analysis of aluminum - Ceramic composites

Imre Fekete Ibolya Zsoldos István Kozma

Publication Name: Materials Science Forum

Publication Date: 2017-01-01

Volume: 885

Issue: Unknown

Page Range: 286-291

Description:

The increasingly widespread use of syntactic metal foams is due to their excellent energy absorbing characteristics. Several research groups deal with developing methods that can further improve this characteristic. Several literature analyses have been devoted to the effects of materials selection, cell size and wall thickness of the reinforcing element on the compression strength. In this work an in situ test necessary for the modeling of the failure process introduced. The aluminumceramic composite foams were cyclically upset. The geometry of the test specimen was reconstructed at a certain point of the compression test by μCT technology and digital image analysis. The failure process was characterized by volume change, by the number of broken shells and by the formation of shear plane as a function of the deformation.

Open Access: Yes

DOI: 10.4028/www.scientific.net/MSF.885.286