Az új algoritmusok és kódolási eljárások alkalmazása a mobil hírközlésben és informatikában = Application of new algorithms and coding procedures in mobile communications and computing

A kutatási munka során az alábbi résztémákban értünk el eredményeket: - mobil IP, - all IP hálózatok, - útkeresési algoritmusok, - hívásátadási algoritmusok, - mobil technológiák együttműködése, - a szolgáltatás minősége (QoS), - a mobil és informatikai hálózatok és rendszerek biztonsági kérdései, - több-felhasználós vétel, - kódosztásos többszörös hozzáférés, - forgalmi modellezés, - kódkonstrukció kódosztásos technológiákhoz, - kvantum számítástechnikai eljárások, - gráfelmélet, - kombinatorikus optimalizálás. A fenti szakterületeken végzett kutatásaink eredményei közül azokat emeljük ki, amelyeket az alábbi témákban értünk el: - A heterogén mobil hálózatok együttműködési problémái, - A mobil Internet Protokoll alkalmazásával kapcsolatos vizsgálatok, - Többfelhasználós detekciós módszerek a kódosztásos többszörös hozzáféréses mobil rendszerekben, - A heterogén mobil hálózatok forgalmi modellezése, - A mobil informatikai és távközlési hálózatok, rendszerek és szolgáltatások - biztonsági kérdései, - Kvantum számítástechnika és mérnöki alkalmazásai, - Útkeresési és csatornakijelölési algoritmusok fejlesztése és vizsgálata mobil hálózatok számára, alkalmazott gráfelmélet. A kutatásban résztvevők az eredményeket három megvédett PhD disszertációban, egy benyújtás előtt álló akadémiai doktori értekezésben és több beadás előtt álló PhD értekezésben használták fel. A tudományos iskola publikációs listája 135 elemből áll. | The members of the Scientific School have got new results in the following scientific fields: - Mobile IP, all IP networks, - Routing algorithms, - Hand-over algorithms, - Interworking of heterogeneous mobile technologies, - Quality of services (QoS), - Security problems of mobile and information networks and systems, - Multi-user detection, - Code division multiple access, - Traffic modeling, - Code construction for code division technologies, - Quantum computing, - Graph theory, - Combinatorial optimization. On the above mentioned scientific field we have the most important results in the following areas: - Interoperability issues of heterogeneous mobile networks, - Investigations on the applicability of mobile Internet Protocol, - Multi-user detection methods in code division multiple access systems, - Traffic models of heterogeneous mobile networks, - Security issues of mobile information and telecommunication networks, systems and services, - Quantum computing and its engineering applications, - Development and research of routing and channel assigning algorithms for mobile networks, application of the graph theory. The participants of the research used their results in three defended PhD theses, in a dissertation for DSc title, and in some other PhD theses before the final process. The number of the publications of the Scientific School is 135

On Centralized and Distributed Frequency Assignment in Frequency Hopping (Cognitive Radio) Cellular Networks

Frequency Assignment is an important approach to mitigate multicell interference in cellular systems. In this paper, we consider the frequency assignement in such systems with frequency hopping. In particular we focus our attention on cognitive radio cellular systems as one of the very promising future access technologies, taking IEEE 802.22 as an example, which is currently under standardization. While the optimal frequency assignment for such a system is conceptually straightforward – as well as computationally complex – we demonstrate that usage of distributed methods leads to high loss of assignment efficiency. In addition w

“Beyond the grassland”: habitat use of extensively grazing cattle, sheep

The role of extensive grazing in nature conservation is growing. The historical importance of this management type in Europe is widely acknowledged, but detailed, systematic description of the practices and of the related traditional knowledge is still absent. Our aim was to study which habitat types were grazed and what was their role in the extensive grazing systems during the last 80 years. We carried out 147 structured interviews in 38 landscapes throughout the Carpathian Basin, with 3–5 informants/landscape. The number of actively grazing cattle, sheep and pigs, their year-round habitat use and the proportion of herds actively tended were documented for four characteristic historical periods (before, during and after socialist cooperatives and after EU Accession). The numbers of grazing cattle and sheep had decreased substantially by 2010 (by 71% and 49%, respectively), while pig grazing almost disappeared by the 1970s. Cattle primarily grazed habitats with taller vegetation. Sheep grazed dry pastures and stubbles, while pigs were driven into marshes and forests. In general, the importance of dry and wet grasslands increased, while the significance of marshes, stubble fields, vegetation along linear elements, second growth on hay meadows, wood-pastures and forests decreased over time. Approximately half of the grazed habitats were not typical pasture grasslands, and functioned as supplementary pastures during droughts, autumn and winter. The number of habitat types grazed per month per site dropped, and herding decreased substantially, in particular in the case of cattle and pigs. It can be stated that the majority of these extensive grazing systems could be considered as agroforestry and silvopastoral systems. Contributing factors of the economic and social changes of the examined period included the collapse of the communist-era legal framework, the intensification of livestock husbandry, EU Common Agricultural Policy (CAP) regulations, and the rise of a nature conservation ethic. We conclude that agricultural policies should take into account the full spectrum of habitat types necessary for the effective operation of extensive grazing systems. Our results encourage forest grazing for nature conservation purpose, thus under strictly defined conditions.peerReviewe