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Found 6278 publications

MILP models of a patient transportation problem

Tamás Hajba Adrian Horváth Martin Tóth

Publication Name: Central European Journal of Operations Research

Publication Date: 2024-12-01

Volume: 32

Issue: 4

Page Range: 903-922

Description:

With ageing societies and increasing number of patients, there is a growing need for quality services that help transporting non-urgent patients to hospitals. In logistics, patient transportation problems are usually modeled as a dial-a-ride problem. In a Dial-a-Ride problem, a fleet of vehicles is providing the delivery services between the loading points and the delivery destinations. The demands are known in advance. In most cases the total travel distance of the vehicles is to be minimized. In this paper, we consider a specific dial-a-ride problem, where a single vehicle is used to transport patients to the same hospital. In determining the optimal route, the multiple and different travel needs of patients, such as their maximum travel time, are also taken into consideration. We introduce 4 different mixed integer linear programming models of the routing problem. Finally, the efficiency of the four models was compared using some real-life problems by solving them with a commercial solver.

Open Access: Yes

DOI: 10.1007/s10100-023-00902-z

Genetic parameters of gestation length trait in dromedary camels (Camelus dromedarius)

Szabolcs Bene P. Nagy Ferenc Szabó Péter J. Polgár J. Juhász

Publication Name: Acta Veterinaria Hungarica

Publication Date: 2021-09-03

Volume: 69

Issue: 3

Page Range: 249-255

Description:

Gestation length (GL) data of dromedary camels were analysed for the period from 2007 to 2018. The database of the largest dairy camel herds (Dubai, United Arab Emirates) was used in this study. The data of 4,084 camels included in the assessment were classified into six ecotypes (Emirati, Emirati cross, Black, Pakistani, Saudi-Sudanese and Saudi cross). The aim of the study was to describe the heritability of GL of camels and the breeding value (BV) of sires for this trait. The genetic parameters of GL were estimated by the General Linear Model method and two Best Linear Unbiased Prediction (BLUP) animal models as well. The mean (±SE) of GL of camels was 384.3 ± 0.2 days. The direct heritability of GL (0.26 ± 0.06-0.36 ± 0.08) was higher than the maternal heritability (0.00 ± 0.05-0.13 ± 0.06) obtained. The maternal permanent environmental effect (0.15 ± 0.05) was similar to the results estimated previously in dromedary camel, but higher than the data reported by relevant sources in other species. Based on the results of this study it can be concluded that the GL of dromedary camels is a species-specific value similar to that in cattle, which is less affected by the maternal influence. Considerable differences (16 days) exist among male dromedaries in their BV for the GL trait.

Open Access: Yes

DOI: 10.1556/004.2021.00033

Shift in the annual growth cycle of grapevines (Vitis vinifera L.) in West Hungary

K. Kozma A. Pozsgai E. Kovács J. Puskás

Publication Name: Applied Ecology and Environmental Research

Publication Date: 2018-01-01

Volume: 16

Issue: 2

Page Range: 2029-2042

Description:

Regional climate change has noticeable influence on grape and wine production in West Hungary. Sopron and Zala wine-growing regions are among the potential winners of the climate change, previously rather unsuitable for viticulture. Over the past 30 years, the minimum and maximum temperatures significantly increased, the precipitation decreased, nevertheless, the convective precipitation increased by 14 days during the growing season. Each climate indicator has changed between 1986 and 2015 compared to the previous 30 years (1956-1985). One of the effects of climate change is a significant shift in the annual growth cycle of grapevines (phenological phases). Budbreak begins nearly 8 days earlier, flowering 7 days and the veraison 8 days, while the harvest has been shifted to a date 11 days respect to the previous period. The time between the budbreak and the flowering has shortened by 4.5 days.

Open Access: Yes

DOI: 10.15666/aeer/1602_20292042

Predatory Medical Journals in Patent Literature: A Hidden Threat

Lóránt Dávid Mehdi Dadkhah Mihály Hegedűs

Publication Name: Advanced Pharmaceutical Bulletin

Publication Date: 2025-11-01

Volume: 15

Issue: 4

Page Range: 693-699

Description:

Purpose: The negative impact of potential predatory journals has been widely discussed, primarily within academic contexts. However, their influence beyond academia remains underexplored. This study aims to address that gap. Methods: The current editorial utilised a sample list of 8 potential predatory medical journals. We compiled a list of potential predatory medical journals using the discontinued titles list in Scopus and the current blocklists. Then their patent-to-paper citations have been examined to understand the dissemination of questionable medical publications outside of academia. Results: This indicates that potential predatory medical journals received 483,848 citations from scholarly works and 4,251 citations from patents. Conclusion: When patents cite papers from predatory journals, flawed information may propagate, or potentially leading to wrongful patent rejections and wasted resources. This serves as a warning for the patent community to take action against potential predatory journals.

Open Access: Yes

DOI: 10.34172/apb.025.46153

Applying clustered artificial neural networks to enhance contaminant diffusion prediction in geotechnical engineering

Edina Koch Shaymaa Alsamia

Publication Name: Scientific Reports

Publication Date: 2024-12-01

Volume: 14

Issue: 1

Page Range: Unknown

Description:

This paper introduces a novel approach using Clustered Artificial Neural Networks (CLANN) to address the challenge of developing predictive models for multimodal dataset with extreme parameter values. The CLANN method strategically decomposes the dataset, derived from Finite Element Analysis (FEA), into clusters, each representing distinct diffusion behaviors, and applies specialized neural networks within these clusters. The CLANN model was rigorously evaluated and demonstrated superior accuracy and consistency compared to traditional methods such as the Adaptive Neuro-Fuzzy Inference System (ANFIS) and fuzzy expert systems. While these conventional models struggled to capture the full range of diffusion dynamics, particularly under extreme conditions, CLANN consistently provided predictions that closely aligned with the actual FEA data across all scenarios. The versatility of the CLANN approach extends beyond its application to soil contamination. Its ability to handle complex, multimodal datasets suggests that this methodology can be generalized to a wide range of scientific and engineering problems characterized by similar data structures. This makes CLANN not only a powerful tool for geotechnical engineers but also a promising framework for broader applications where traditional models fall short. The findings of this study pave the way for more accurate, reliable, and adaptable predictive modeling in diverse domains, enhancing our ability to manage and mitigate environmental and engineering challenges.

Open Access: Yes

DOI: 10.1038/s41598-024-79983-y

Mercenaries reloaded? Applicability of the notion of 'mercenaries' in relation to private military companies and their employees

János Kálmán

Publication Name: Acta Juridica Hungarica

Publication Date: 2013-12-01

Volume: 54

Issue: 4

Page Range: 367-383

Description:

The purpose of this study is to present the notion of mercenaries laid down in literature and in international law, as its applicability to private military companies and their employees so. The first chapter examines the use of the notion of mercenaries in literature and in international treaties. It explores whether the definition laid down in international treaties, reflect customary international law, or not. The second chapter of the study scrutinizes the various conditions listed in the afore-mentioned notions and tries to find out whether and to what degrees private military companies and their employees meet them. The final conclusion of this paper - of the perspective of international law - is that private military companies and their employees, in accordance with the rules of international law, cannot be considered mercenaries. © 2013 Akadémiai Kiadó.

Open Access: Yes

DOI: 10.1556/AJur.54.2013.4.5

Aerodynamic Design and Simulation of a Racing Car with Regard to the Front Wing †

Gusztáv Fekete Ildikó Molnár Levente Zsolt Chudi Ferenc Szlivka

Publication Name: Engineering Proceedings

Publication Date: 2025-10-01

Volume: 113

Issue: 1

Page Range: Unknown

Description:

One of the key elements in the aerodynamic balance of a race car is the front wing, which is responsible for generating downforce to enhance grip. This article aims to investigate the change in downforce on a Formula Student racecar with a newly mounted front wing and aerodynamic elements at different angles of attack by means of Computational Fluid Dynamics (CFD). In addition, the effect of the front wing on the position of the center of pressure was also investigated, which highly influences the steering stability of the car. The study proved that by applying the front wing, together with additional aerodynamic elements, the downforce increases by 38%, while the center of pressure moves closer to the front axes by approximately 30% (compared to when there is no wing on the car), which results in an understeered but stable controllability.

Open Access: Yes

DOI: 10.3390/engproc2025113062

Resource allocation and its distributed implementation

Szabolcs Póta Zs T. Kosztyán Bencsik Andrea

Publication Name: Innovations and Advanced Techniques in Computer and Information Sciences and Engineering

Publication Date: 2007-01-01

Volume: Unknown

Issue: Unknown

Page Range: 511-518

Description:

During the execution of a project (investment, innovation etc.), three important parameters must be kept in mind: we have to execute the project as soon as possible, with minimal total cost and not to exceed resource (manpower, materials, engines etc.) availabilities. Why does it important to execute the project as soon as possible with minimal total cost? If more than one company compete for the execution of an investment project, usually the chance of winning the tender will be higher if a company can execute the project with minimal total project time (TPT) and minimal total project cost. This problem could already be handled in the 60s and 70s with network planning (CPM, MPM, PERT etc.), scheduling (Gantt Diagrams, LOB etc.) and other related cost-minimizing (CPM/COST, MPM/COST etc.) techniques. The most difficult problem was to handle the resources. During the execution of a project we must keep in view the resources, because these resources are usually straitened. There are well-defined number of labours, engines and so on. If we would like to execute the project with minimal TPT and minimal total project cost and optimal use of the resources (manpower, materials, engines etc.) the problem becomes easily so hard to solve (already at 5000-10000 activities) that computers available today cannot find the solution within a reasonable time. The real problem is more complicated, because before the execution of the project we can only estimate the duration time, (variable) cost and resource need of activities. In real life it is common that the duration time of project activities cannot be estimated correctly. In this paper a novel algorithm is introduced by which an optimal resource allocation with minimal total cost for any arbitrary project could be determined. Moreover, this algorithm also handles the competences of the human resources. A distributed problem solving environment is also introduced that implements the above mentioned optimal resource allocation algorithm with a parallel branch and bound method. The system is built on the Jini technology [44]. It is a dynamic, service-oriented infrastructure that utilizes spare cycles of networked workstations in an efficient way and solves computation intensive problems more easily due to the parallelization. © 2007 Springer.

Open Access: Yes

DOI: 10.1007/978-1-4020-6268-1_90

Quantum structure classification by Kohonen Self-Organizing Map and by Fuzzy C-Means algorithm

Márk Farkas Ákos Nemcsics Antal Ürmös László T. Kóczy

Publication Name: Icsse 2013 IEEE International Conference on System Science and Engineering Proceedings

Publication Date: 2013-11-18

Volume: Unknown

Issue: Unknown

Page Range: 313-318

Description:

Nowadays the nanostructures, formed on the way of self assembly are intensively investigated both in the basic and the applied sciences. In our paper, we investigate the structures on III-V compund semiconductor based materials, which are grown by epitaxial process. This process is analized by the beta version of Quantum Structure Analyzer 1.0, which is developed in C# langague, in the Microsoft© Visual Studio 2008 development environment. This software operates with the help of the Kohonen Self-Organizing Maps (SOM) algorithm and with the help of the Fuzzy C-Means algorithm. In present work, in the preface we give a short introduction of Molecular Beam Epitaxy (MBE), after this we introduce the algorithms, applied in this software. Finally, we demonstrate the results of the program. © 2013 IEEE.

Open Access: Yes

DOI: 10.1109/ICSSE.2013.6614682