Administrative systems and reforms across the European Union - towards sustainability?

This paper presents an overview of the particularities of the administrative systems across the European Union. With more and more countries becoming members of the Union, legal and administrative harmonisation becomes more important than ever. Both internal and external aspects may trigger changes, whose scale will be dependent of many factors. It must be realised that administration in this case does not just mean dealing with bureaucratic red tape and obtaining documents, but rather it largely refers to the communal services provided by administrative units to their citizens. These will naturally have an effect on the socio-economic status of the served area, but lest one forget that there is also an environmental aspect to it. This paper will present an overview of the key aspects of administrative divisions across the European Union, and highlight the most important recent changes in the structure, and considering their sustainability aspects too

Alsóági kockázatmérési eszközök és portfólió-kiválasztás

A piaci kockázatelemzés utáni időkben legelterjedtebb és legnépszerűbb eszköze a kockáztatott érték, vagyis a VaR módszere, amely befektetői döntéshozatalnál a veszteségek szintjének korlátozásában nyújthat segítséget. A szerzők azonban nemcsak a VaR és a részvényportfolió-kezelés kapcsolatát mutatják be. Az úgynevezett alsóági kockázatokat (downside risk) elemző és bemutató elemzési eszközök köre meglehetősen régi múltra tekint vissza: gyakorlatilag a klasszikus portfoliókezelés megszületésével párhuzamosan fejlődött ki. A cikk elején az alsóági kockázatmérés eszközeinek bemutatására kerül sor, ezt követően a szerzők különböző portfolió-optimalizálási kritériumokat fogalmaznak meg és az eljárásokat szemléltetik a magyar részvénypiacon elvégzett számításokkal. Az elemzés során a megfelelő feltételek mellett azt is megvizsgálják, miként lehet ötvözni a klasszikus portfolió-elméletet és az ott használatos hozam-szórás diagramokat az alternatív alsóági kockázatelemzés fogalmaival és optimalizálási problémáival

Twitter bot detection using deep learning

Social media platforms have revolutionized how people interact with each other and how people gain information. However, social media platforms such as Twitter and Facebook quickly became the platform for public manipulation and spreading or amplifying political or ideological misinformation. Although malicious content can be shared by individuals, today millions of individual and coordinated automated accounts exist, also called bots which share hate, spread misinformation and manipulate public opinion without any human intervention. The work presented in this paper aims at designing and implementing deep learning approaches that successfully identify social media bots. Moreover we show that deep learning models can yield an accuracy of 0.9 on the PAN 2019 Bots and Gender Profiling dataset. In addition, the findings of this work also show that pre-trained models will be able to improve the accuracy of deep learning models and compete with Classical Machine Learning methods even on limited dataset

On the boundary conditions of cerebral aneurysm simulations

Cerebral aneurysms are bulges appearing on brain arteries. The development, growth and rupture has been intensively studied using numerical tools. We present a series of studies covering many of the open questions related to the boundary conditions used in numerical simulations, namely the inlet, outlet and the wall. The effect of boundary conditions cannot be overestimated; yet it received much less attention than it would have deserved.An analytical formula of the pulsating pipe flow with rigid walls is used to study the effects of the varying parameters of the cardiac cycle. Both idealised and real geometries are used to study the propagation of the boundary effects, and to analyse the effects of distensible boundaries.Our results provide useful criteria for the necessary inlet and outlet length. We found that the deformability of wall boundaries has a significant influence; however, simulations with rigid walls are still able to capture the main hemodynamic properties of the flow.The results can be effectively used in the simulation of cerebral aneurysm and provide a firmer ground in a broader sense for hemodynamic simulations