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Publications - 6342

A Localized Version of the Method of Fundamental Solutions in a Multi-level Context

Csaba Gáspár

Publication Name: Periodica Polytechnica Civil Engineering

Publication Date: 2023-01-01

Volume: 67

Issue: 3

Page Range: 716-724

Description:

The Method of Fundamental Solutions is applied to the Laplace equation. Instead of using the traditional approach with external source points and boundary collocation points, the original domain decomposed into a lot of smaller, overlapping subdomains, and the Method of Fundamental Solutions is used to the individual local subdomains. After eliminating the local source points, local schemes are obtained. Instead of constructing a global scheme, the local subproblems are solved sequentially, in an iterative way. This mimics a multiplicative Schwarz method with overlapping subdomains, which assures the convergence of the method. Combining the iteration with a simple Seidel-type method, the resulting iteration is used as a smoothing procedure of a multi-level method. The points belonging to the coarse and fine levels are defined by a quadtree-generated cell system controlled by the boundary of the original domain. The multi-level character of the obtained method makes it possible to reduce the necessary number of iterations, that is, the overall computational cost can be significantly reduced. Moreover, the solution of large and ill-conditioned systems is completely avoided. The method is illustrated through several numerical test examples.

Open Access: Yes

DOI: 10.3311/PPci.21535

Purification of model dairy wastewaters by Ozone, Fenton pre-treatment and membrane filtration

Zsuzsanna László E. Lakatos Mihály Zakar Gábor Keszthelyi-Szabó Dániel Imre Farkas

Publication Name: Periodica Polytechnica Chemical Engineering

Publication Date: 2020-01-01

Volume: 64

Issue: 3

Page Range: 357-363

Description:

This study aimed to investigate the effect of ozone and Fenton-reaction as a pre-treatment before ultrafiltration of model dairy waste waters containing sodium caseinate. Filtration resistances and pollutant retentions were determined and compared. It was found, that both pre-treatment increased the retention, achieving almost 100 % pollutant elimination efficiency after short term pre-oxidation. The effect of Fe-ion concentration on Fenton pretreatment efficiency also was examined, and it was found that higher concentration resulted in decreased filtration resistances, revealing that coagulation-flocculation effect of reactants has dominant role in the protein separation efficiency. The presence of lactose also affects the pollutant removal efficiency, it promotes fouling in presence of Fenton reagents.

Open Access: Yes

DOI: 10.3311/PPch.15046

SDG adoption and firm risk: The impact of ESG performance, investor confidence, and agency cost

Muneza Kagzi Sonia Chawla Vishal Dagar Amar Rao Rajat Sharma

Publication Name: International Review of Economics and Finance

Publication Date: 2025-07-01

Volume: 101

Issue: Unknown

Page Range: Unknown

Description:

This study investigates the nexus between firm-level Sustainable Development Goals (SDG) adoption and firm risk using a unique dataset of National Stock Exchange (NSE) 500 companies from 2019 to 2024. It constructs a novel SDG adoption index to assess this relationship and reveals a noteworthy reduction in firm risk associated with SDG adoption. The results remain robust after a battery of robustness checks, including endogeneity concerns using 2SLS IV and system GMM and sample selection bias through Heckman's two-stage methods. Furthermore, the mechanism test indicates that SDG adoption reduces firm risk by enhancing investor confidence, improving ESG performance, and reducing agency costs. In addition, heterogeneity analyses demonstrate that the impact is more accentuated for enterprises with higher information asymmetry, higher board gender diversity, and non-state ownership. The results carry significant implications for investors, corporations, and policymakers seeking to mitigate risk and foster sustainable practices, particularly within the context of the COVID-19 pandemic and emerging markets.

Open Access: Yes

DOI: 10.1016/j.iref.2025.104205

Body Mass and Aerobic Capacity are Robust Predictors of the 2000m Ergometer Rowing Performance: A Laboratory Study

Feren Ihász Celal Bulgay Zsolt Bálint Katona Angéla Somogyi Ádám Balog Anna Pápai-Horváth Zoltán Alföldi Attila Szabo

Publication Name: International Journal of Kinesiology and Sports Science

Publication Date: 2025-01-01

Volume: 13

Issue: 2

Page Range: 78-85

Description:

Purpose: Predicting performance in sports competitions is a popular topic in research. However, only a few studies exist in rowing sports, which suggest that some anthropometric and performance indices might predict performance in various situations. Methods: This work expands past research by examining the effects of five anthropometric measures, such as body mass index (BMI), height, weight, fat, and muscle, and three performance indicators, such as aerobic capacity, maximum speed, and force, while also considering the training history of 38 elite rowers (Mage = 16.89 ± 1.85, range 14.7 to 22.6 years, 61% males) participating in a national championship. Results: Apart from BMI, all measures correlated statistically significantly with the 2000m rowing time. A bootstrapped forward multiple regression yielded the best model with only two predictors (R2 =.995), aerobic capacity and body mass, accounting for 99.5% variance in the 2000m rowing time. Conclusions: While the results support previous findings, such robust prediction has not been reported in the literature. We conjecture that the differences from other past works rest with the high-pressure 2000m performance preceding a national championship. If these findings could be replicated, their practical implication is substantial in preparatory training for rowing contests.

Open Access: Yes

DOI: 10.7575/aiac.ijkss.v.13n.2p.78

On the application of subjective learning algorithms in decision-making

Peter Varlaki László Nádai

Publication Name: Iccc 2005 IEEE 3rd International Conference on Computational Cybernetics Proceedings

Publication Date: 2005-12-01

Volume: 2005

Issue: Unknown

Page Range: 329-331

Description:

The paper deals with computation of optimal ratios for capital investment processes using adaptive methods and taking into consideration subjective probabilities, which can ensure regularizing influence on above algorithms.

Open Access: Yes

DOI: 10.1109/ICCCYB.2005.1511596

General formulation of resilience for designing process networks

Ákos Orosz Jean Pimentel Ferenc Friedler Andres Argoti

Publication Name: Computers and Chemical Engineering

Publication Date: 2022-09-01

Volume: 165

Issue: Unknown

Page Range: Unknown

Description:

Herein, the formula proposed for quantifying the resilience of engineering systems, including processing systems, is general in several aspects. The structure of a system can be highly complex where the numbers of loops, raw materials, and products are not limited. The mathematical models of the operating units can be either linear or nonlinear for simulating the effect of the failures. The damage caused by an unexpected event can result in various levels of operation for the operating units. The proposed formula is also general in the sense that all possible combinations of failures are considered. The problem formulation, the related structure representation, the enumeration and evaluation of possible failures are based on the P-graph framework and its algorithms. The proposed formula for resilience is applicable to any complex engineering system whose behavior is primarily determined by its structure, including supply chains, information systems, municipal infrastructures, and electrical transmission networks.

Open Access: Yes

DOI: 10.1016/j.compchemeng.2022.107932

Tensor product transformation-based modeling of an induction machine

Miklós Kuczmann Zoltan Nemeth

Publication Name: Asian Journal of Control

Publication Date: 2021-05-01

Volume: 23

Issue: 3

Page Range: 1280-1289

Description:

The paper demonstrates a tensor product (TP) model transformation-based framework for an induction machine (IM). The state space model of an IM is highly nonlinear, thus the Takagi–Sugeno (TS) fuzzy model-based quasi-linear parameter-varying (qLPV) representation can be a good alternative approach of machines modeling. The paper presents the basics of IM state space modeling, how the TP transformation can be applied in details. The control of IM is always a pivotal point; hence, options of feedback control are discussed. The main goal of this paper is to present the whole process of IM TP transformation-based modeling including a control system.

Open Access: Yes

DOI: 10.1002/asjc.2468

A Novel Control Scheme Based on Exact Feedback Linearization Achieving Robust Constant Voltage for Boost Converter

Miklós Kuczmann Tamas Orosz Miklos CSIZMADIA

Publication Name: Electronics Switzerland

Publication Date: 2023-01-01

Volume: 12

Issue: 1

Page Range: Unknown

Description:

This paper presents a novel form of feedback linearization control (FBL) of boost-type DC/DC converter: to reach highly accurate output voltage control. Integral action has been inserted into the block diagram of the control scheme. The state-space model of the boost converter is highly nonlinear. Accordingly, the design procedure of the controller is more complex. The paper presents the state-space modeling of the boost converter and details the design procedure of the nonlinear FBL controller step by step. The main goal of this paper is to highlight the importance of the error integrator in the FBL control loop. The proposed method has been tested by a numerical example and compared with an existing and validated two-loop controller. Both the dynamical and steady-state behavior of the examined boost converter performed better than the reference system. The steady-state error of the output voltage is almost eliminated, while the dynamical error decreased to 5% in comparison to the two-loop controller.

Open Access: Yes

DOI: 10.3390/electronics12010057

Practical robot edutainment activities program for junior high school students

János Botzheim Takuya Hashimoto Noriko Takase Naoyuki Takesue Naoyuki Kubota

Publication Name: Lecture Notes in Computer Science Including Subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics

Publication Date: 2016-01-01

Volume: 9834 LNCS

Issue: Unknown

Page Range: 111-121

Description:

In this paper, we describe the approach of the research activities in order to take advantage of the creativity and thinking abilities in practical research of the robot for junior high school female students. The students mainly understand the main idea and the definition of robots and they created them based on information and advice provided by our university and teachers. As a result, the students created the robots by their unique imagination.

Open Access: Yes

DOI: 10.1007/978-3-319-43506-0_10