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Publications - 6278

Applications of the conjugate gradient method for implicit feedback collaborative filtering

Istvan Pilaszy Gabor Takacs Domonkos Tikk

Publication Name: Recsys 11 Proceedings of the 5th ACM Conference on Recommender Systems

Publication Date: 2011-12-06

Volume: Unknown

Issue: Unknown

Page Range: 297-300

Description:

The need for solving weighted ridge regression (WRR) problems arises in a number of collaborative filtering (CF) algorithms. Often, there is not enough time to calculate the exact solution of the WRR problem, or it is not required. The conjugate gradient (CG) method is a state-of-the-art approach for the approximate solution of WRR problems. In this paper, we investigate some applications of the CG method for new and existing implicit feedback CF models. We demonstrate through experiments on the Netflix dataset that CG can be an efficient tool for training implicit feedback CF models. © 2011 ACM.

Open Access: Yes

DOI: 10.1145/2043932.2043987

Overview of the COMPASS diagnostics

M. Aftanas V. Weinzettl I. Ďuran P. Bilková G. Veres M. Hron F. Zacek J. Zajac M. Berta P. Hacek J. Mlynar D. Naydenkova R. Melich D. Šesták J. Adamek F. Janky J. Brotankova J. Stöckel J. Horacek R. Pánek R. Dejarnac J. Havlicek R. Gomes M. Manso D. Jares J. Ghosh A. Szappanos V. F. Shevchenko R. Scannell V. K. Kiselov M. Walsh H. W. Müller V. Igochine A. Silva S. Zoletnik P. Böhm G. Anda Tsv Popov D. Sarychev S. Nanobashvili

Publication Name: Fusion Engineering and Design

Publication Date: 2011-10-01

Volume: 86

Issue: 6-8

Page Range: 1227-1231

Description:

The COMPASS tokamak, a divertor device with clear H-mode and ITER-relevant geometry, has been re-installed in IPP Prague after its transport from CCFE in UK. The first plasma was achieved in December 2008. Many new diagnostic tools with both high temporal and spatial resolutions have been developed to address the scientific programme of COMPASS focused on H-mode physics and pedestal investigations. In the paper, an overview of existing and in near future planned diagnostics (magnetic, spectroscopy, microwave, probe and beam/particle) on COMPASS is given including their basic technical specifications and achievements. © 2011 EURATOM. Published by Elsevier B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/j.fusengdes.2010.12.024

A stochastic model for analyzing the interpretability-accuracy trade-off in interpretable fuzzy systems using nested Hyperball structures

Krisztián Balázs László T. Kóczy

Publication Name: 8th Conference of the European Society for Fuzzy Logic and Technology Eusflat 2013 Advances in Intelligent Systems Research

Publication Date: 2013-12-01

Volume: 32

Issue: Unknown

Page Range: 72-79

Description:

Our recent work proposed a new meaning preservation approach together with a parameterizable nested hyperball structured search space for interpretable fuzzy systems in order to solve a problem of inconsistency observed in conventional interpretable fuzzy knowledge bases and simultaneously to address the adjustment of the trade-off between interpretability and accuracy. Based on intuitive reasonings and simulation results a conjecture was formulated about favorable trade-off adjustment properties of the proposed method. The aim of the present paper is to construct a mathematical model, in which the conjectured properties can be analyzed and formally verified. Some computational considerations about the interpretation of the resulting knowledge bases are also made. © 2013. The authors -Published by Atlantis Press.

Open Access: Yes

DOI: DOI not available

Lost working time due to ill health in Hungary in 2021

József Vitrai

Publication Name: Orvosi Hetilap

Publication Date: 2024-12-22

Volume: 165

Issue: 51

Page Range: 2026-2032

Description:

Introduction: Deteriorating of workers' health means reduced performance for the employers, lower incomes for workers and increased health care costs for the country. Objective: Examination of the loss of working time due to ill health in 2021, its gender differences and changes compared to 2019, and the differences of the Hungarian data compared to other countries. Methods: Working time loss in the 30-64 years age group was analyzed by the number of working days lost in 2021 due to disability and 'premature' deaths in the 30-64 years age group, and by the number of future working days lost by the deceased until retirement age. Data on disability and mortality were taken from the Global Burden of Disease Study database, and population and mortality data from the National Statistical Office and Eurostat. Hungarian data were compared with the corresponding figures for the Visegrad countries and Austria. Results: In the year 2021, 30-64-year-old workers lost one in seven working days, meaning they could not work at all for 37 working days. In addition, more than 117,000 years that could be worked until retirement were lost. For women, the loss of working time was due to disability, for men more to mortality. Compared to 2019, the number of working days lost per capita increased by 7% and the future loss of working days due to mortality by 40%. Hungary was similar to other countries in the number of days lost per capita due to limitation, but the number of deaths was much higher than in the others. Discussion: The female excess of disability and the male excess of mortality are assumed to be due to different attitudes towards disease: men perceive their health better and therefore use health care less often. The higher mortality in Hungary compared to other countries reflects the lower effectiveness of prevention and medical care. The high rate of deaths that can be prevented or avoided with medical intervention is largely due to deficiencies in the health system, and not to a low willingness to seek medical care. Conclusions: The results show that reducing time lost to work requires a different approach by gender. To mitigate losses, improvements in the effectiveness of public health and medical interventions are needed. Measures to promote healthy lifestyles and create an enabling environment are also essential to increase the country's competitiveness.

Open Access: Yes

DOI: 10.1556/650.2024.33205

Space sustainability: Current regulatory challenges

Gábor Sulyok Mónika Ganczer Balázs Bartóki-Gönczy

Publication Name: Hungarian Journal of Legal Studies

Publication Date: 2024-12-20

Volume: 65

Issue: 2

Page Range: 260-281

Description:

Nowadays, outer space is becoming increasingly congested, contested and competitive. Humanity's growing dependence on outer space and experiences with the new space race have necessarily turned the attention of the international community to the safety, security and sustainability of space activities. This paper focuses on space sustainability and seeks to highlight some of its most important regulatory challenges. These challenges include the establishment of an appropriate space traffic management system, the mitigation of space debris, and the utilization of space resources. Following the overview of related problems, the paper examines the urgency and the modalities of appropriate legal regulation.

Open Access: Yes

DOI: 10.1556/2052.2024.00552

Sustainable Uses of 3D Printing Applied to Concrete Structures †

Szabolcs Fischer Szabolcs Szalai Hanna Csótár Gusztáv Baranyai

Publication Name: Engineering Proceedings

Publication Date: 2024-01-01

Volume: 79

Issue: 1

Page Range: Unknown

Description:

This study investigates the application of honeycomb-patterned PLA as a reinforcement in concrete structures. The research focused on identifying the optimal 3D printing layout for this reinforcement and examining how the orientation of 3D-printed PLA affects the mechanical properties of the concrete. The study compares the performance of concrete reinforced with 3D-printed PLA to both unreinforced concrete and concrete reinforced with recycled amorphous aggregate from printing waste. The results demonstrate how printing orientation influences concrete strength and the potential for using recycled PLA to enhance sustainability in construction.

Open Access: Yes

DOI: 10.3390/engproc2024079055

Trace metal and metalloid levels in surface water of Marcal River before and after the Ajka red mud spill, Hungary

István Vass Andrea Szabó Nagy János Szabó

Publication Name: Environmental Science and Pollution Research

Publication Date: 2013-11-01

Volume: 20

Issue: 11

Page Range: 7603-7614

Description:

The aim of this study was to compare and assess the dissolved concentrations of trace elements (As, Zn, Hg, Cd, Cr, Ni, Pb and Cu) in surface water of Marcal River before and after the red mud spill that occurred in Ajka, western Hungary, in October 2010. The caustic sludge flooded the surrounding settlements and polluted the nearby Torna Creek, which flows through the Marcal and Raba rivers into the Danube. A total of 92 surface water samples were collected from the Marcal River in the period of 2007-2012 and analysed for dissolved trace metal(loid)s by atomic absorption spectroscopy method. After the spill, the water management authority initially focused on acid dosing of surface waters to lower pH and was effective in lowering both pH and metal(loid) concentrations. Among the dissolved trace metal(loid)s, arsenic and nickel levels were moderately higher in the Marcal River 2 years since the spill compared to that observed in the pre-disaster period. The concentrations of dissolved trace metal(loid)s did not exceed the European water quality standards and the US Environmental Protection Agency aquatic life criteria values (excluding one sample for cadmium). © 2013 Springer-Verlag Berlin Heidelberg.

Open Access: Yes

DOI: 10.1007/s11356-013-2071-5

Observability Conditions for Speed Sensorless Induction Motor Models with Neglected or Included Iron Loss Representation

Krisztian Horvath

Publication Name: International Conference on Electical Drives and Power Electronics

Publication Date: 2021-01-01

Volume: Unknown

Issue: Unknown

Page Range: 97-101

Description:

Iron loss is usually neglected in induction motor models used for speed sensorless control and observer design. Thus, the complexity of control and estimator algorithms are reduced. However, the application of a more accurate model can improve the performance, hence the inclusion of iron loss in the machine model is becoming more widespread. But the effect of iron loss modeling on observability has not been analyzed yet. In this paper, observability conditions are presented for nonlinear state-space models with included iron loss. Furthermore, the results are compared with the observability properties of the traditional models where iron loss is ignored.

Open Access: Yes

DOI: 10.1109/EDPE53134.2021.9604110

Global challenges and the ‘farm to fork’ strategies of the European Green Deal: Blessing or curse

Judit Oláh Popp József A. Nyéki M. Neményi

Publication Name: Progress in Agricultural Engineering Sciences

Publication Date: 2024-12-12

Volume: 20

Issue: 1

Page Range: 101-111

Description:

The article evaluates how well the goals of the European Green Deal are justified, especially considering the risks to energy and food security arising from the conflict between Russia and Ukraine. We agree with the objectives of the European Green Agreement as a whole, but whether some of the objectives which feature in the EASAC study can be achieved by 2030 is questionable, and the description of the tools necessary to achieve the objectives is incomplete. Among other things, there is hardly any mention of the role played by precision farming with digitalization, which is a revolutionary change from an ecological and economic point of view, in reducing the use of synthetic inputs, in regenerating the original state of the soil, in reducing GHG emissions, thus in increasing biodiversity, and at the same time in intensifying production, and finally in expanding the application of biotechnology. We examine these areas in our analysis. Some of the objectives of the EASAC study to be achieved by 2030 are subject to debate, and the description of the information and communication conditions necessary to achieve the objectives is incomplete. The IoT (Internet of Things) responds to global and local challenges: it integrates the precision technologies, WSNs (Wireless Sensor Networks), artificial intelligence, mobile field (Smart Small Robots) and remote data loggers (UAVs: Unmanned Air Vehicles and satellites), Big Data, and cloud computing. Consequently, decision support is increasingly developing into unmanned decision making. IoT (Internet of Things) is the basis of “Farm to Fork” and “Lab to Field” monitoring approaches. This article evaluates the implementation of European Green Agreement objectives in light of energy and food security risks arising from the Russia-Ukraine conflict. While overall support for the agreement exists, the feasibility of certain EASAC study objectives by 2030 is called into question due to insufficient tools specifications. Notably absent is the emphasis on precision farming with digitalization, which is a transformative ecological and economic practice. Our analyses look into its function in reducing synthetic inputs, soil regeneration, GHG emission reduction, biodiversity enhancement, production intensification, and biotechnology development. Debates surround EASAC study objectives for 2030, despite limited information and communication restrictions. The Internet of Things (IoT) arises as a solution, combining precision technology, WSNs (wireless sensor networks), AI (artificial intelligence), smart small robots, UAVs (unmanned aerial vehicles), satellites, big data, and cloud computing. As a result, decision support turns toward unmanned decision-making, with IoT laying the groundwork for “Farm to Fork” and “Lab to Field” monitoring systems.

Open Access: Yes

DOI: 10.1556/446.2024.00113