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Found 6289 publications

Differences, constraints and key elements of providing local sharing economy services in different-sized cities: A Hungarian case

Katalin Czakó Dávid Fekete Kinga Szabó Marcell Tóth

Publication Name: Resources

Publication Date: 2019-09-01

Volume: 8

Issue: 3

Page Range: Unknown

Description:

The business models of sharing economy services can differ fromeach other in different-sized cities. This paper provides a deeper understanding of the implementation of locally operating services for car, bicycle and office sharing in the urban environment. Our goal is to reveal the differences between the capital city and an economically well-developed city in order to provide beneficial findings to the development of the presently operating services, or to the possible implementation of future services. Methodology of the paper applies the Business Model Canvas approach (BMC). We introduce a comparative analysis using data from the Hungarian database, which records details of all the publicly visible sharing economy services countrywide. The results show that BMC can reflect the main differences, constraints and key elements in the business models of sharing economy services. We can say that, in the case of a bike sharing service operated in the non-capital city, there is more segmentation than seen in the same service in the capital. There are significant price differences, especially in the case of long-term tickets. The number of inhabitants and private capital remain the biggest constraints in the case of car-sharing services, but there is also a possibility of implementation in the non-capital cities by applying small-scale services with a good value proposition and segmentation.

Open Access: Yes

DOI: 10.3390/resources8030147

New dimensions of internal controls in banking after the GFC

Laszlo Vasa Csaba Lentner Pál P. Kolozsi Zoltán Zéman

Publication Name: Economic Annals Xxi

Publication Date: 2019-08-20

Volume: 176

Issue: 3-4

Page Range: 38-48

Description:

The weakness of the control function of governments and central banks was the main regulatory cause of the global financial crisis (GFC) broke out in 2007, but the suboptimal regulatory environment «corrupted» the quality of internal control and audit of banks as well. After the crisis, corporate governance issues appeared in the focus of international organizations. In this paper, we present the relevant international recommendations aimed at improvement of the weak corporate governance practices of the banking sector. Based on the comparison of pre- and post-crisis internal control functionalities which are presented as a meta-analysis and a systematic review of the existing empirical researches, the authors conclude that the stricter guidelines could and can have a positive impact on banks' operations stabilizing through the strengthening of internal control practices.

Open Access: Yes

DOI: 10.21003/ea.V176-04

The r-switching-stable graphs

Jeanette C. McLeod Beáta Faller Brendan D. McKay

Publication Name: Discrete Applied Mathematics

Publication Date: 2019-08-15

Volume: 266

Issue: Unknown

Page Range: 16-29

Description:

Bondy and Mercier (2011) defined a switching at a vertex of a digraph to be the operation of reversing the directions of the edges incident with that vertex. They asked which digraphs have the property that every switching produces a digraph isomorphic to the original, which they called switching-stability. That version of the problem was solved for oriented graphs by the second author and Schweitzer (McKay and Schweitzer, 2014). In this paper we generalise the problem in several directions. As well as oriented graphs, we consider graphs with coloured vertices or edges, and various types of switching which apply to them. We further consider r-switching-stable graphs, which are those for which any r distinct switchings together produce a graph isomorphic to the original. Finally, we consider what happens if the isomorphism relation between graphs is weakened to isomorphism up to converse (reversal of all directed edges or changing of all colours). Our proofs employ a combination of group theory and combinatorics, with a small amount of computer assistance.

Open Access: Yes

DOI: 10.1016/j.dam.2018.12.013

Session recommendation via recurrent neural networks over fisher embedding vectors

Bálint Daróczy Frederick Ayala-Gómez Domokos Kelen Anna Ország András Benczúr

Publication Name: Sensors Switzerland

Publication Date: 2019-08-02

Volume: 19

Issue: 16

Page Range: Unknown

Description:

Recommendation services bear great importance in e-commerce, shopping, tourism, and social media, as they aid the user in navigating through the items that are most relevant to their needs. In order to build recommender systems, organizations log the item consumption in their user sessions by using different sensors. For instance, Web sites use Web data loggers, museums and shopping centers rely on user in-door positioning systems to register user movement, and Location-Based Social Networks use Global Positioning System for out-door user tracking. Most organizations do not have a detailed history of previous activities or purchases by the user. Hence, in most cases recommenders propose items that are similar to the most recent ones viewed in the current user session. The corresponding task is called session based, and when only the last item is considered, it is referred to as item-to-item recommendation. A natural way of building next-item recommendations relies on item-to-item similarities and item-to-item transitions in the form of “people who viewed this, also viewed” lists. Such methods, however, depend on local information for the given item pairs, which can result in unstable results for items with short transaction history, especially in connection with the cold-start items that recently appeared and had no time yet to accumulate a sufficient number of transactions. In this paper, we give new algorithms by defining a global probabilistic similarity model of all the items based on Random Fields. We give a generative model for the item interactions based on arbitrary distance measures over the items, including explicit, implicit ratings and external metadata to estimate and predict item-to-item transition probabilities. We exploit our new model in two different item similarity algorithms, as well as a feature representation in a recurrent neural network based recommender. Our experiments on various publicly available data sets show that our new model outperforms simple similarity baseline methods and combines well with recent item-to-item and deep learning recommenders under several different performance metrics.

Open Access: Yes

DOI: 10.3390/s19163498

Nitrogen recovery from wastewater and human urine with hydrophobic gas separation membrane: experiments and modelling

Andras Jozsef Toth J. Nagy Juho Kaljunen

Publication Name: Chemical Papers

Publication Date: 2019-08-01

Volume: 73

Issue: 8

Page Range: 1903-1915

Description:

In agriculture, the human urine could have been used as a natural fertilizer, although there are some problems with the direct utilization, such as the presence of micropollutants in urine, odour and storage of large volume of urine. Therefore, nutrients, such as nitrogen, can be recovered from urine. Continuous flow laboratory membrane reactor was built to investigate nitrogen recovery from wastewater and from human urine. Membrane gas separation method has not been investigated for ammonia recovery from human urine yet. Nitrogen as ammonia gas was recovered in acid using Zeus Aeos™ ePTFE gas-permeable hydrophobic membrane. Acid flux, operating pH, hydraulic retention time and effective membrane surface were experimentally determined. The aim of this work was to verify wastewater experiments in professional flowsheet environment, rigorously modelled with ChemCAD and optimized by dynamic programming optimization method: the membrane separation. Such nitrogen recovery membrane separation has not been published in this professional flowsheet environment yet. The objective function of the process is the ammonia harvesting efficiency. Eighty-five percentage ammonia harvesting efficiency can be reached with 60 membrane surface area/reactor volume ratio, at 35 °C feed temperature with 350 L/m2h acid and in 8 h’ hydraulic retention time. It can be stated that this separation method is based on physical phenomena without any biological factors. The focus for nitrogen treatment in a wastewater treatment plant is removal instead of recovery. It can be determined that this system is capable for the nitrogen recovery from wastewater, and it can reduce the ammonia content of human urine too.

Open Access: Yes

DOI: 10.1007/s11696-019-00740-x

Molecular taxonomic evaluation of Anabaena and Nostoc strains from the Mosonmagyaróvár Algal Culture Collection

G. Gell T. Kiss Zoltán Molnár N. Makra V. Soós Vince Ördög L. Vörös E. Balázs A. Juhász

Publication Name: South African Journal of Botany

Publication Date: 2019-08-01

Volume: 124

Issue: Unknown

Page Range: 80-86

Description:

The taxonomy of genera Anabaena and Nostoc is very controversial. They are typically paraphyletic within phylogenetic trees and show similar morphological characters. The present study aimed to determine the taxonomic relationships among Anabaena and Nostoc strains of the Mosonmagyaróvár Algal Culture Collection (MACC)using 16S rRNA and rbcLX gene sequences. We concluded on the basis of the number of unsuccessful amplifications that more of the examined MACC Nostoc cultures are axenic than the Anabaena cultures. In agreement with previous studies we noticed that the applied phylogenetic algorithms gave congruent results in phylogenetic analyses. However, the genus Nostoc clearly was found not monophyletic in the present study and this finding differed from many of the previous studies. Molecular results contradicted the previous morphology-based classification of some MACC cyanobacteria strains, therefore polyphasic taxonomic approaches are required for the reliable identification of cyanobacterial species. Some strains seemed to be identical based on the alignment of 16S rRNA or rbcLX sequences.

Open Access: Yes

DOI: 10.1016/j.sajb.2019.03.008

Numerical solver for analyzing the thermal behaviour of permanent magnet synchronous machines

Lotfi Abdelhakim

Publication Name: Aip Conference Proceedings

Publication Date: 2019-07-24

Volume: 2116

Issue: Unknown

Page Range: Unknown

Description:

This study investigates a 3D numerical analysis of the thermal behavior of a permanent magnet (PM) motor, performed by Finite Element Method (FEM) by using open source Feel++ software. In the developed FEM model, the windings and the stator are treated as homogeneous medium with equivalent thermal parameters and the effective properties to characterize the thermal behaviour are calculated based on the volume-weighted average over all constituents. In order to check the accuracy of the computed temperatures, experimental tests were performed in the transient-state. The thermal analyses based on the numerical method are compared with the measured results taken from the prototype machine.

Open Access: Yes

DOI: 10.1063/1.5114557

The reclassification of 37 strains from The Mosonmagyaróvár Algal Culture Collection, Hungary, which were previously identified as Anabaena (Cyanobacteria, Nostocaceae)

K. Szenthe H. D. Laughinghouse Péter Bálint B. Pap Gergely Maróti Zoltán Molnár D. E. Berthold S. Katona C. Kilgore N. Horváth Vince Ördög F. Bánáti L. Vörös

Publication Name: South African Journal of Botany

Publication Date: 2019-07-01

Volume: 123

Issue: Unknown

Page Range: 333-340

Description:

Study on 37 MACC isolates previously identified as “Anabaena,” a freshwater filamentous heterocytous taxon, were carried out using the 16S rRNA. The study found that most of the strains were misidentified at genus level. Three clusters of phylogenetically and morphologically similar taxa were identified. The previous determinations were amended with their new taxonomic classifications (partly due to changes in cyanobacterial classification). Some morphological structures could not be found in the cultures (e.g. akinetes). Molecular data revealed that 6 of the 37 strains are Desmonostoc, 8 are members of the genus Nostoc, 19 strains bear genetic resemblance to the genus Trichormus and 4 strains remain unresolved. Clades were established by 16S rRNA similarity and p-distances. The goal of this study was to amend the strain designations in this collection. This study reveals the necessity to revisit established culture collections that originally used only morphological classifications for species identification.

Open Access: Yes

DOI: 10.1016/j.sajb.2019.03.014

Implant for augmentation of Cerebral blood flow trial-1 (IMPact-1). A single-arm feasibility study evaluating the safety and potential benefit of the Ischemic Stroke System for treatment of acute ischemic stroke

Vinod Puri Hans Christoph Diener Laszlo Csiba Ilona Adam Bernd Griewing Attila Csanyi Nasli R. Ichaporia Attila Valikovics Andreas Hetzel Natan Bornstein Stefan Schwab Dietmar Schneider Subhash Kaul Dheeraj Khurana

Publication Name: Plos One

Publication Date: 2019-07-01

Volume: 14

Issue: 7

Page Range: Unknown

Description:

Background The Ischemic Stroke System is a novel device designed to deliver stimulation to the sphenopalatine ganglion(SPG).The SPG sends parasympathetic innervations to the anterior cerebral circulation. In rat stroke models, SPG stimulation results in increased cerebral blood flow, reduced infarct volume, protects the blood brain barrier, and improved neurological outcome. We present here the results of a prospective, multinational, single-arm, feasibility study designed to assess the safety, tolerability, and potential benefit of SPG stimulation inpatients with acute ischemic stroke(AIS). Methods Patients with anterior AIS, baseline NIHSS 7–20 and ability to initiate treatment within 24h from stroke onset, were implanted and treated with the SPG stimulation. Patients were followed up for 90 days. Effect was assessed by comparing the patient outcome to a matched population from the NINDS rt-PA trial placebo patients. Results Ninety-eight patients were enrolled (mean age 57years, mean baseline NIHSS 12 and mean treatment time from stroke onset 19h). The observed mortality rate(12.2%), serious adverse events (SAE)incidence(23.5%) and nature of SAE were within the expected range for the population. The modified intention to treat cohort consisted of 84 patients who were compared to matched patients from the NINDS placebo arm. Patients treated with SPG stimulation had an average mRS lower by 0.76 than the historical controls(CMH test p = 0.001). Conclusion The implantation procedure and the SPG stimulation, initiated within 24hr from stroke onset, are feasible, safe, and tolerable. The results call for a follow-up randomized trial (funded by BrainsGate; clinicaltrials.gov number, NCT03733236).

Open Access: Yes

DOI: 10.1371/journal.pone.0217472