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Found 6412 publications

Stability of fuzzy cognitive maps with interval weights

Istvan A. Harmati Laszlo T. Koczy

Publication Name: Proceedings of the 11th Conference of the European Society for Fuzzy Logic and Technology Eusflat 2019

Publication Date: 2020-01-01

Volume: Unknown

Issue: Unknown

Page Range: 756-763

Description:

In fuzzy cognitive maps (FCMs) based modelling paradigm, the complex system's behaviour is gathered by the causal connections acting between its main characteristics or subsystems. The system is represented by a weighted, directed digraph, where the nodes represent specific subsystems or features, while the weighted and directed edges express the direction and strength of causal relations between them. The state of the complex system represented by the so-called activation values of the nodes, that is computed by an iterative method. The FCM based decision-making relies on the assumption that this iteration reaches an equilibrium point (fixed point), but other types of behaviour, namely limit cycles and chaotic patterns may also show up. In practice, the weights of connections are estimated by human experts or machine learning methods. Both cases have their own uncertainty, which can be represented by using intervals as weights instead of crisp numbers. In this paper, sufficient conditions are provided for the existence and uniqueness of fixed points of fuzzy cognitive maps that are equipped with interval weights, which also ensure the global asymptotic stability of the system.

Open Access: Yes

DOI: DOI not available

Breaking and Making Constitutional Rules: The Constitutional Effects of the Financial Crisis in Hungary

Zoltán Szente

Publication Name: Constitutions in the Global Financial Crisis A Comparative Analysis

Publication Date: 2016-01-01

Volume: Unknown

Issue: Unknown

Page Range: 245-262

Description:

No description provided

Open Access: Yes

DOI: 10.4324/9781315573571-14

Configuring Green Growth in the Age of Sustainability: Energy and Resource Use Trends in EU Economies

Md Kamal Uddin Mohammad Fakhrul Islam Md Rashed Jewel Rana Md Zubair Ahmad Md Nazmul Islam Jihad

Publication Name: Sustainable Development

Publication Date: 2026-01-01

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In an era of intensifying global competition where nations aggressively pursue economic advancement, the imperative to balance progress with ecological preservation has become paramount. However, the race for advancement should not harm nature or future generations. Our study investigates the drivers that can lead to green growth, aligning with sustainable development principles that integrate economic growth, environmental stewardship, and social equity as per the UN's Sustainable Development Goals (SDGs), across nine Western European countries from 2010 to 2019. By utilizing panel data from reputable sources, this research investigates the influence of globalization, natural resource rents, renewable energy consumption, trade openness, and total energy consumption on green growth. Employing contemporary panel diagnostic tests, cointegration analyses, and fixed- and random-effects models, the study also validates its findings through quantile regression, fully modified ordinary least squares, and dynamic ordinary least squares. Our study has fulfilled its destiny by finding the right drivers. According to various analyses, globalization and trade openness consistently and significantly promote green growth, confirming their potential as reliable mechanisms for achieving green growth. The complex impact of renewable energy consumption and natural resource rents opens a new door for exploration by revealing the transitional barriers, such as initial costs and policy lags, in contrast to maintaining the resource rent tendency. However, the beneficial impact of total energy consumption of carbon and fossil fuel underscores the urgency of effective resource utilization and a shift toward renewable sources to decouple growth from unsustainable consumption before running out.

Open Access: Yes

DOI: 10.1002/sd.70627

Foliar Application of Copper-Tetramine-Sulphate from Microelectronic Waste to Improve Yield and Quality Parameters of Winter Wheat

Pál Szakál Judit Molnár Eduard Gubó Dávid Vasas Tamás Szakál Bálint Szüle Zsolt Giczi

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 1069-1074

Description:

The growth of the world's population is an increasing challenge for agricultural production. Improving soil productivity is the key to ensuring the quantity, quality and safety of food for a growing population. In addition to macroelements, microelements also play an important role in the biochemical processes. A large percentage of soils in Hungary show a deficiency in copper. For three years, we treated the leaves of winter wheat with a copper-tetramine-sulphate complex derived from microelectronic waste. Aim to provide an alkaline pH range of 9.3 for effective foliar treatment. Treatments were applied on 10 m2 small plots at 0; 0.1; 0.3; 0.5; 1.0; and 2.0 kg×ha-1 copper dose in the budding and flowering phenological stages with copper-tetramine-sulphate produced from microelectronic waste. After harvesting the crop from the plots, the yield, raw protein, and gluten content were measured. In the copper-deficient soil, a significant increase in yield and protein and gluten levels was observed after treatment with copper foliar fertiliser. The most significant increase in yield was obtained in the treatment at flowering (0.40 t/ha), with a 0.37 % increase in crude protein content and a 1.95 % increase in wet gluten content.

Open Access: Yes

DOI: 10.3303/CET24114179

Applying NeuralODE-based Cardiovascular Model Identification for Experimental Data Analysis

Balázs Benyó Ákos Antal J. Geoffrey Chase Bálint Szabó Katalin Kovács Ákos Szlávecz

Publication Name: Saci 2024 18th IEEE International Symposium on Applied Computational Intelligence and Informatics Proceedings

Publication Date: 2024-01-01

Volume: Unknown

Issue: Unknown

Page Range: 437-442

Description:

Recent model-based diagnostic methods have been found promising to provide non-invasive perfusion markers to assess the efficacy of fluid therapy, the most common treatment method for acute circulatory failure (ACF). The development of these model-based diagnostic methods requires the identification of the central arterial pressure curve based on the femoral arterial pressure. This current study presents improvements of the previously suggested NeuralODE-based identification method by suggesting the use of a physiologically interpretable parameter set of the Tube-load model-based transfer function for the physiological system analysis and suggesting a calculation method decreasing the measurement error-caused uncertainty of the identification parameter, called pulse transfer time.

Open Access: Yes

DOI: 10.1109/SACI60582.2024.10619737

Experimental Investigation of Conventional and Advanced Control Strategies for Mini Drone Altitude Regulation with Energy-Aware Performance Analysis

Miklós Kuczmann Áron Ballagi Barnabás Kiss

Publication Name: Machines

Publication Date: 2026-01-01

Volume: 14

Issue: 1

Page Range: Unknown

Description:

The energy efficiency and hover stability of unmanned aerial vehicles are critical factors, since improper battery utilization and unstable control are major sources of operational failures and accidents. The proportional–integral–derivative (PID) controller, which is applied in approximately 97% of multirotor unmanned aerial vehicle (UAV) systems, is widely used due to its simplicity; however, it is sensitive to external disturbances and often fails to ensure optimal energy utilization, resulting in reduced flight time. Therefore, the experimental investigation of advanced control methods in a real physical environment is well justified. The objective of the present research is the comparative evaluation of seven control strategies—PID, linear quadratic controller with integral action (LQI), model predictive control (MPC), sliding mode control (SMC), backstepping control, fractional-order PID (FOPID), and H∞ control—using a single-degree-of-freedom drone test platform in a MATLAB R2023b-Arduino hardware-in-the-loop (HIL) environment. Although the theoretical advantages and model-based results of the aforementioned control methods are well documented, the number of real-time comparative HIL experiments conducted under identical physical conditions remains limited. Consequently, only a small amount of unified and directly comparable experimental data is available regarding the performance of different controllers. The measurements were performed at a reference height of 120 mm under disturbance-free conditions and under wind loading with a velocity of 10 km/h applied at an angle of 45°. The controller performance was evaluated based on hover accuracy, settling time, overshoot, and real-time measured power consumption. The results indicate that modern control strategies provide significantly improved energy efficiency and faster stabilization compared to the PID controller in both disturbance-free and wind-loaded test scenarios. The investigations confirm that several advanced controllers can be applied more effectively than the PID controller to enhance hover stability and reduce energy consumption.

Open Access: Yes

DOI: 10.3390/machines14010098

General formulation for the resilience of processing systems

Ákos Orosz Jean Pimentel Ferenc Friedler

Publication Name: Chemical Engineering Transactions

Publication Date: 2020-01-01

Volume: 81

Issue: Unknown

Page Range: 859-864

Description:

Resilience is one of the key indicators of processing systems, it expresses the behaviour of the system as a result of expected or unexpected failures. This indicator can be essential during systems design and operation, especially, when the system is part of or related to a critical infrastructure. The numerous contributions on systems resilience are related to a wide range of applications, however, there is no general uniform framework for resilience evaluation. For instance, most studies examine resilience as a function of the continuous parameters of the system, usually avoiding the influence of its structure. In the current work, a general framework for determining the structural resilience of processing systems is presented. This framework derives on formulas that satisfy the requirements of the original definition of resilience. The formerly developed P-graph framework is the mathematical basis of the procedure for determining the indicator. The resilience of the system is calculated as a function of the operative subprocesses for all possible failures and is a normalized indicator on [0, 1]. The examination of two industrial case studies shows that the proposed resilience can be an appropriate indicator to be considered in process design.

Open Access: Yes

DOI: 10.3303/CET2081144

Analysis of Potential Energy Transition Schemes in Hungary: from Natural Gas to Electricity

László Palkovics Csaba Gondola Tibor Gulyás László Palkovics

Publication Name: Chemical Engineering Transactions

Publication Date: 2024-01-01

Volume: 114

Issue: Unknown

Page Range: 871-876

Description:

Hungary, as a landlocked nation with limited raw material resources, faces significant challenges in ensuring a stable energy supply, necessitating extensive interconnectors with neighbouring countries for gas, oil, and electricity. While progress has been made, especially in electricity interconnections, the Russian-Ukrainian conflict and the EU’s decarbonisation goals for 2050 introduce new pressures on energy security. Hungary's energy trilemma—balancing access and affordability, environmental targets, and security—guides its strategy as it seeks an optimal energy mix. By 2050, energy demand is projected to hold steady at 210 TWh, though the current 65 % fossil fuel share, largely imported, highlights Hungary’s vulnerabilities (exposure to risks and insecurities in its energy supply). Goals include net-zero emissions, reduced foreign dependency, and manageable energy costs, with targets to reduce gas consumption to 4×109 m3 (1.5 ×109 m3) and ensure over 50 % of the energy mix is carbon-neutral electricity. The paper examines three key actions based on statistical data to achieve these targets: (a) reducing natural gas dependency, (b) boosting domestic alternative sources like local gas production and green solutions, and (c) enhancing energy system flexibility through regulation, storage, and generation. These strategies are assessed for their potential to satisfy the trilemma’s demands and provide a resilient path forward amidst evolving challenges.

Open Access: Yes

DOI: 10.3303/CET24114146

Structural analysis of titanium alloys

Ibolya Zsoldos K. Kulcsár J. Kónya

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

The material of choice for dental implant devices is titanium alloy (Ti-6Al-4V). In this study, the two fundamental manufacturing technologies of dental implant prostheses are compared. Titanium alloy specimens and models were created with conventional precision casting and with modern, innovative additive manufacturing technologies. Hereupon, the microscopic analysis of specimen cut-offs was carried out. We were focusing on fundamental microstructural differences. The thus-created specimen models were subjected to tensile tests for comparative examination.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012029