Search in Publications

Found 6674 publications

Benchmarking methodology for IPv4aaS technologies: Comparison of the scalability of the Jool implementation of 464XLAT and MAP-T

Ádám Bazsó Gabor Lencse

Publication Name: Computer Communications

Publication Date: 2024-04-01

Volume: 219

Issue: Unknown

Page Range: 243-258

Description:

A novel method is proposed for the performance and scalability measurements of the IPv4-as-a-Service (IPv4aaS) technologies. It works according to the dual Device Under Test (DUT) setup of RFC 8219 and is suitable for benchmarking any of the five IPv4aaS technologies: Combination of Stateful and Stateless Translation (464XLAT), Dual-Stack Lite (DS-Lite), Lightweight 4over6 (Lw4o6), Mapping of Address and Port with Encapsulation (MAP-E), and Mapping of Address and Port using Translation (MAP-T). The method is based on the reduction of the aggregate of Customer Edge (CE) and Provider Edge (PE) devices to a stateful network address translation from IPv4 to IPv4 (stateful NAT44) gateway. The most important advantage of the novel method is that a stateful NAT44 tester can be used instead of a technology-specific tester, which usually does not exist. The proposed method is validated by the examination of the performance and scalability of the Jool implementation of 464XLAT and MAP-T. Scalability is defined by both (1) how performance increases with the number of active Central Processing Unit (CPU) cores; and (2) how performance decreases with the increasing number of concurrent sessions. Maximum connection establishment rate and throughput are used as performance metrics. The scalability of 464XLAT and MAP-T is measured from 1 to 16 CPU cores and from 1 million to 256 million connections. The measurement details and results are fully disclosed and discussed.

Open Access: Yes

DOI: 10.1016/j.comcom.2024.03.007

Spatial and spectral properties of the dummy-head during measurements in the head-shadow area based on HRTF evaluation

György Wersényi

Publication Name: Institute of Noise Control Engineering of the Usa 35th International Congress and Exposition on Noise Control Engineering Inter Noise 2006

Publication Date: 2006-12-01

Volume: 7

Issue: Unknown

Page Range: 4477-4486

Description:

In accurate and repeatable measurements dummy -heads are often used to model the average human head and body. They are suited for standardized measurements and for investigating the human spatial hearing and localization performance. The monaural Head-Related Transfer Functions (HRTFs) of the dummy-head can be used for various investigations. This paper uses the HRTF-set of a Brüel & Kjaer head and torso simulator focusing on the so called monaural head-shadow area, where one of the ears is shadowed by the head itself. Based on long-term measurements using the bare torso as well as other accessories (glasses, clothing etc.) on it, the extent of the head-shadow area will be presented in frequency and space. The head-shadow area is investigated in connection with the overall SNR of the measurement and sensitivity domains of the ears. Conclusions are drawn for binaural recognition in human spatial hearing using low-frequency 'bright spots' and high-frequency information during lateral-contralateral evaluation.

Open Access: Yes

DOI: DOI not available

A new efficient tour construction heuristic for the Traveling Salesman Problem

Boldizsár Tüű-Szabó Ali Jawad Ibada László T. Kóczy

Publication Name: ACM International Conference Proceeding Series

Publication Date: 2021-04-10

Volume: Unknown

Issue: Unknown

Page Range: 71-76

Description:

The creation of the initial population is an essential part of the population based evolutionary algorithms. An appropriate initial population could lead to much faster convergence speed; in contrast, an inappropriate initial population could even cause getting stuck in a local optimum. In this paper, we will propose a new efficient heuristic method to create initial individuals for the Traveling Salesman Problem (TSP), which we will call Circle Group Heuristic (CGH). The results show that CGH creates better tours compared with other well-known heuristic tour construction methods.

Open Access: Yes

DOI: 10.1145/3461598.3461610

TURNING THE TRIPLE BURDEN OF UKRAINIAN DEPOPULATION INTO A QUADRUPLE BURDEN: THE RESULTS OF A SURVEY AMONG UKRAINIAN REFUGEE WOMEN

Sándor Remsei Eva Berde

Publication Name: Economics and Sociology

Publication Date: 2025-01-01

Volume: 18

Issue: 1

Page Range: 296-312

Description:

The effects of the Russian-Ukrainian war on Ukraine's demographic landscape are immense. One key consideration is whether Ukrainian refugee women intend to return to their country after the war ends. If the return is planned, the question of whether they would wish to have children is also relevant. This study explored these issues by surveying women who fled to Hungary and the Netherlands. Among those surveyed, 42% did not plan to return under any circumstances, and only 12% intended to return even if their home area came under Russian control. Logistic regression was used to identify factors influencing the intention to return, with reluctance to have additional children and income earned through employment emerging as the strongest explanatory factors. However, we found only modest associations between the intention to return and other variables. Our findings suggest that deeply rooted personal preferences shape these women’s plans.

Open Access: Yes

DOI: 10.14254/2071-789X.2025/18-1/16

A Systematic Review of Life Cycle Assessment Reporting Practices and Transparency for Mono-Crystalline Silicon Photovoltaic Systems

Chew Tin Lee Kok Sin Woon Zhen Xin Phuang Kyle Sebastian Mulya Hong Sheng Loh Petar Sabev Varbanov

Publication Name: Chemical Engineering Transactions

Publication Date: 2025-01-01

Volume: 122

Issue: Unknown

Page Range: 97-102

Description:

Mono-crystalline silicon (mono-Si) PV modules account for around 70 % of global c-Si production, making robust environmental assessments essential. Life Cycle Assessment (LCA) is widely used for this purpose, yet inconsistent data reporting limits transparency and comparability. While prior reviews have explored environmental impacts and parameter trends, none have systematically evaluated reporting quality in mono-Si PV LCAs. To address this, the current review conducted a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA)-guided review of 32 mono-Si PV LCA studies published from 2019 to 2024. Each was assessed using the ISO 14040/14044 framework and IEA guidelines, with a focus on key elements such as functional unit, system boundary, data sources, software, characterization models, and data quality analysis. The review applied both a descriptive summary of common practices and a grading rubric to evaluate reporting transparency. Results reveal major inconsistencies, with fewer than half of the studies meeting international standards. This underscores the urgent need for harmonized reporting protocols in mono-Si PV LCA literature.

Open Access: Yes

DOI: 10.3303/CET25122017

Hydrodynamic Modeling and Comprehensive Assessment of Pier Scour Depth and Rate Induced by Wood Debris Accumulation

Muhanad Al-Jubouri Richard P. Ray

Publication Name: Hydrology

Publication Date: 2024-04-01

Volume: 11

Issue: 4

Page Range: Unknown

Description:

This study mainly investigates the impact of debris accumulation on scour depth and scour hole characteristics around bridge piers. Through controlled experiments with uniform sand bed material, the influence of various debris shapes (high wedge, low wedge, triangle yield, rectangular, triangle bow, and half-cylinder), upstream debris length, downstream debris extension, and debris thickness on scour depth and scour hole area and volume around the cylindrical pier were analyzed. The findings revealed that the shape and location of debris in the water column upstream of piers are key factors that determine the depth of scour, with high wedge shapes inducing the deepest scour and potentially the largest scour hole, particularly when positioned close to the pier and fully submerged. Scenarios in which triangle bow debris was submerged at full depth upstream of the pier closely resembled situations devoid of debris. Conversely, debris extension downstream of the pier was found to reduce local scour depth while concurrently enlarging the dimensions of the scour hole. The existing scour prediction equations tend to overestimate scour depth in scenarios involving debris, particularly when applying effective and equivalent pier width. This discrepancy arises because these equations were originally developed to predict scour depth around piers in the absence of debris. In response, a refined model for predicting scour induced by debris was proposed, integrating factors such as upstream debris length, downstream extension, obstruction percentage, and debris shape factor. This model demonstrated strong agreement with experimental data within the scope of this study and underwent further validation using additional experimental datasets from other research endeavors. In conclusion, this experimental study advances the comprehension of scour processes around cylindrical bridge piers, providing valuable insights into the role of debris characteristics and positioning.

Open Access: Yes

DOI: 10.3390/hydrology11040052

Efficacy of Advanced Robotic and Virtual Therapy in the Treatment of Acute and Subacute Stroke Patients: a Feasibility Study

Tamás Haidegger József Tollár Bence Csutorás Nándor Prontvai Blanka Törő Szilvia Kóra Petra Kós Barbara Kopácsi Veronika Keresztesy Júlia Kutas Dóra Kozma

Publication Name: Acta Polytechnica Hungarica

Publication Date: 2025-01-01

Volume: 22

Issue: 10

Page Range: 83-102

Description:

The aim of this study is to compare the effectiveness of advanced robotic therapy, virtual therapy and conventional physiotherapy in the rehabilitation of patients with acute and subacute stroke. In addition, we aim to further demonstrate the importance of an early mobilisation exercise program in the management of acute stroke patients. Participants (first-time ischaemic stroke patients in acute or subacute stages) were randomly divided into three equal groups (n=10 persons/group): a robot-assisted early mobilisation + virtual reality therapy (ROB+VR) group, a robot-assisted early mobilisation + conventional physiotherapy (ROB+FIZ) group, and a conventional physiotherapy (CON) group. Each group performed a 3-week-long training program (1 hour/session, 5 days/week). The results were measured before and after the exercise. The primary outcome measure used was the modified Rankin Scale (mRS) which indicates the severity of disability in daily activities and measures the degree of independence of the individual. The secondary outcomes were measured by the EuroQoL 5 dimensions questionnaire 5 levels version (EQ-5D-5L), the Berg Balance Scale (BBS), the Barthel Index (BI), and the 6-minute walking test (6mWT). All the three groups showed improvements in most outcomes. The scores for BI, EQ-5D-5L, and mRS showed significant improvements in quality of life. Comparing the groups, the ROB+VR group showed the greatest improvement in the scores in almost all of the tests. From the test scores, the 6-minute walk test had the highest improvement at the end of the therapy (94.58% improvement). Our results show that early robotic mobilization, followed by a movement program, combined with a virtual reality therapy, significantly improve both the speed and quality of rehabilitation after a stroke.

Open Access: Yes

DOI: 10.12700/APH.22.10.2025.10.6

The P-graph approach for systematic synthesis of wastewater treatment networks

Ákos Orosz Kirti M. Yenkie Jean Pimentel Heriberto Cabezas Ferenc Friedler

Publication Name: Aiche Journal

Publication Date: 2021-07-01

Volume: 67

Issue: 7

Page Range: Unknown

Description:

Wastewater treatment consists of three or four sequential stages: preliminary, primary, secondary, and tertiary. Each stage can comprise multiple alternative technologies that can perform the same tasks with different efficiencies, operating times, and costs. Thus, we propose a systematic approach for designing wastewater treatment networks by utilizing principles of mathematical modeling and generating an exhaustive enumeration of all the possible technologies and their connections during the early stages of designing a treatment facility. Some of these structures are nonintuitive and include recycling, reprocessing, bypasses, and multiple technologies in parallel or series to remove the same contaminant. The nonintuitive structures with multiple technologies may provide a measure of resilience compared to typical heuristic designs. Thus, the combination of P-graph methodology and the sequence of treatment technologies predicted via the optimization algorithm from the maximal structure is based on holistic considerations and does not lead to suboptimal solutions.

Open Access: Yes

DOI: 10.1002/aic.17253

Construction of two-sided bounds for initial-boundary value problems

C. Grossmann Zoltán Horváth

Publication Name: Applied Numerical Mathematics

Publication Date: 2002-08-01

Volume: 42

Issue: 1-3

Page Range: 177-187

Description:

The present paper extends the bounding operator approach developed for boundary value problems to the case of initial-boundary value problems (IBVPs). Following the general principle of bounding operators enclosing methods for the case of partial differential equations are discussed. In particular, continuous discretization methods with an appropriate error bound controlled shift and monotone extensions of Rothe's method for parabolic problems are investigated. © 2001 IMACS. Published by Elsevier Science B.V. All rights reserved.

Open Access: Yes

DOI: 10.1016/S0168-9274(01)00149-0