Véletlenszerű fluktuációk analízisén és hasznosításán alapuló mérési és titkosítási eljárások vizsgálata

Random signals - "noises" - aren’t necessarily hindrances to be eliminated, they can carry information about the examined system. They can also play a constructive role - optimal functioning of some systems are made only possible by appropriate noise application. In the dissertation results are presented in areas which are examples of utilising noises in a constructive role or as an information source. The subject of the first half of the thesis is the analysis of the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange protocol. First, the necessary and sufficient conditions of noise properties for unconditional security are deducted using the tools of mathematical statistics only, giving a mathematical proof for the system's perfect security. Next, the generalization of the protocol is presented, allowing the two communicating parties to use different hardware, i.e. resistors with different values. This result not only makes the practical application of the protocol much easier, but resulted in the reinterpretation of the classical physical description of the original KLJN protocol’s security . Finally the supplement of the generalized protocol is presented, in which the components previously bringing non-ideality and information leakage into the system became a part of the unconditionally secure ideal system, which is evidently a big step forward for the protocol's practical applications. Thereafter a new field of application for using fluctuations as an information source is shown. The presented results about analyzing kayak paddlers' motion signals pointed out that the quality of the paddling is correlated to the fluctuation of the period and stroke impulse, which characterise the period of the motion. Thus the temporal indicators characterizing the period fluctuations and the spectral indicators based on the raw motion signals' signal-to-noise ratio could contain extra information. The latter method of spectral variability analysis could be useful for other periodic signals as well

What kind of noise guarantees security for the Kirchhoff-Loop-Johnson-Noise key exchange?

This article is a supplement to our recent one about the analysis of the noise properties in the Kirchhoff-Law-Johnson-Noise (KLJN) secure key exchange system [Gingl and Mingesz, PLOS ONE 9 (2014) e96109, doi:10.1371/journal.pone.0096109]. Here we use purely mathematical statistical derivations to prove that only normal distribution with special scaling can guarantee security. Our results are in agreement with earlier physical assumptions [Kish, Phys. Lett. A 352 (2006) 178-182, doi: 10.1016/j.physleta.2005.11.062]. Furthermore, we have carried out numerical simulations to show that the communication is clearly unsecure for improper selection of the noise properties. Protection against attacks using time and correlation analysis is not considered in this paper

Power spectral density estimation for wireless fluctuation enhanced gas sensor nodes

Fluctuation enhanced sensing (FES) is a promising method to improve the selectivity and sensitivity of semiconductor and nanotechnology gas sensors. Most measurement setups include high cost signal conditioning and data acquisition units as well as intensive data processing. However, there are attempts to reduce the cost and energy consumption of the hardware and to find efficient processing methods for low cost wireless solutions. In our paper we propose highly efficient signal processing methods to analyze the power spectral density of fluctuations. These support the development of ultra-low-power intelligent fluctuation enhanced wireless sensor nodes while several further applications are also possible

The Effect of Interstellar Absorption on Measurements of the Baryon Acoustic Peak in the Lyman-{\alpha} Forest

In recent years, the autocorrelation of the hydrogen Lyman-{\alpha} forest has been used to observe the baryon acoustic peak at redshift 2 < z < 3.5 using tens of thousands of QSO spectra from the BOSS survey. However, the interstellar medium of the Milky-Way introduces absorption lines into the spectrum of any extragalactic source. These lines, while weak and undetectable in a single BOSS spectrum, could potentially bias the cosmological signal. In order to examine this, we generate absorption line maps by stacking over a million spectra of galaxies and QSOs. We find that the systematics introduced are too small to affect the current accuracy of the baryon acoustic peak, but might be relevant to future surveys such as the Dark Energy Spectroscopic Instrument (DESI). We outline a method to account for this with future datasets.Comment: MNRAS accepted. Minor change

17. századi evangélikus és református énekek kritikai kiadása = Critical edition of the evangelical-lutheran and calvinist hymns in the 17th century

A kutatás célja olyan 17. századi evangélikus és református énekversek kritikai kiadása, amelyek még nem jelentek meg az Régi Magyar Költők Tára 17. századi sorozatában. 3 kutató együttműködésével elkészült a pályázat céljaként megjelölt kézirat. Az RMKT-sorozat 17. köteteként tervezzük kiadását. A kötet 241 gyülekezeti éneket és 15 egyéb protestáns énekverset tartalmaz. Az énekek valamennyi 17. századi kéziratos és nyomtatott forrását (111) összegyűjtöttük. A kézirat az RMKT szabványa szerinti részeket tartalmazza: előszó; kritikai szövegek; dallamok; szövegváltozatokat ismertető apparátus; jegyzetek (egyes források analitikus leírása; kéziratos és nyomtatott források; filológiai, teológiai, verstani, himnológiai és egyéb jegyzetek); mutatók. A szövegek, dallamok és jegyzetek az irodalomtörténet és a himnológia számára számos újdonsággal szolgálnak. A részletes adatfelvétel lehetővé teszi adatbázis készítését. A gyülekezeti énekek mintegy fele fordítás. Nemcsak a magyar fordítástörténet, hanem a nemzetközi kutatás számára is hasznos lehet, hogy eddig feltáratlan német és biblikus cseh nyelvű forrásszövegeket sikerült azonosítanunk. Több egyetemi és más kutatóintézet konferenciáin és kutatószemináriumain vettünk részt, előadásokat tartottunk, néhány részeredményről tanulmány jelent meg. | The aim of our research was to produce a critical edition of 17th century lutheran and protestant sung poems that have not yet been published in the 17th century series of Régi Magyar Költők Tára. As a result of the collaboration of 3 research fellows, the manuscript of the volume marked as our goal in our OTKA-application, is now accomplished. It will be the 17th volume of the series. It contains 241 hymns and 15 further protestant sung poems. We have collected all the 17th century hymn sources (111): printed ones as well as manuscripts. The structure of our manuscript follows the RMKT standards: foreword; critical texts; melodies; guide to textual variants; notes (analitical description of certain sources; written and printed sources; philological, theological, metrical, hymnological and other notes); indexes. The texts, melodies and notes provide a number of novelties to literary history and hymnology. The detailed collection of data allows us to create a database in the future. Some half of the hymns are translations. Our identifying of some German and Biblical Czech text sources that were unrevealed until recently, might be useful not only in Hungarian translation history but also on an international research level. Our team participated at several conferences and research seminars at different universities and research institutes; we delivered lectures; some of our results were published in articles

Universal Arduino-based experimenting system to support teaching of natural sciences

The rapid evolution of intelligent electronic devices makes information technology, computer science and electronics strongly related to the teaching of natural sciences. Today almost everybody has a smart phone that can convert light, temperature, movement, sound to numbers, therefore all these can be processed, analysed, displayed, stored, shared by software applications. The fundamental question is how education can follow this knowledge and how can education take its advantages. Components and methods of modern technology are available for education also, teachers and students can play with parts and tools which were previously used only by engineers. A good example is the very popular Arduino board which is practically an industrial microcontroller whose pins are wired to easy-to-use connectors on a printed circuit board. In this paper we show a universal system which we have developed for the Arduino platform to support experimenting and understanding of the most fundamental principles of the operation of modern devices. We show our related educational concept and discuss the most important features of the system. Open source hardware and software are available and we provide a number of video tutorials as well