Fluktuációk és zajok alap- és interdiszciplináris kutatása fizikai, neurocardiológiai és nanotechnologiai szakterületeken = Basic and interdisciplinary research of noise and fluctuations in physics, neurocardiology and nanotechnology

A fluktuációkkal javított érzékelés alkalmazásához kis méretű és fogyasztású számítógépvezérelt műszereket fejlesztettünk, melyek segítségével megmutattuk, hogy szén nanocső alapú és más szenzorokon végzett zajspektroszkópiai mérések alkalmasak lehetnek különböző gáztípusok vagy akár baktériumok megkülönböztetésére. Digitális jelprocesszor alapú kísérleti eszközöket fejlesztettünk ki, melyekkel elsőként sikerült demonstrálnunk a termikus zajra épülő abszolút biztonságos kommunikáció működését valós rendszeren. Az excimer lézerek késleltetésének sztochasztikus jelek felhasználásán alapuló aktív szabályozásához kifejlesztett módszerünkhöz új hardvert terveztünk, mely hatékonyabb működést tesz lehetővé, additív zaj felhasználásával segíti a késleltetési idő detektálását. Algoritmusokat és szoftvereket fejlesztettünk ki főként ritmuszavar során fellépő EKG-jelek időtartománybeli és spektrális analíziséhez. Emellett vizsgáltuk, hogy az emberi agy hogyan képes a véletlenszerű jelekben elrejtett determinisztikus minták felismerésére és tanulására. Interdiszciplináris kutatási eredményeinkhez tartozik egy baktériumok fotoszintézisének mérésére tervezett számítógépvezérelt fluorométer és a kísérlezető oktatást támogató számos hardver és szoftver kifejlesztése is. A pályázat során megjelent 32 publikáció között szerepel 20 nemzetközi folyóiratcikk (összesített impakt faktor: 37,203), melyek 5 nemzetközi és egy hazai meghívott konferenciaelőadáshoz kötődnek. | We have built low-consumption, small-size computer-controlled devices for fluctuation-enhanced sensing. With these instruments we have shown that noise spectroscopy measurements of carbon nanotubes or other sensors can differentiate between gases or bacteria. We have developed digital signal processor-based experimental devices with which we could be the first to demonstrate the feasibility of thermal noise-driven totally secure communication in a real-world system. We have designed new methods and the associated hardware to enhance the efficiency of the active control of excimer laser delay by using additive noise to improve delay detection. We have developed algorithms and software for the time-domain and spectral analysis of ECG signals recorded mainly during arrhythmias. We have also studied the capacity of the human brain to recognise and learn deterministic patterns hidden in seemingly random signals. Our interdisciplinary results include a computer-controlled fluorimeter for measuring bacterial photosynthesis and several hardware and software developments to support teaching experiments

Review of sound card photogates

Photogates are probably the most commonly used electronic instruments to aid experiments in the field of mechanics. Although they are offered by many manufacturers, they can be too expensive to be widely used in all classrooms, in multiple experiments or even at a home experimentation. Today all computers have a sound card - an interface for analogue signals. It is possible to make very simple yet highly accurate photogates for cents, while much more sophisticated solutions are also available at a still very low cost. In our review we show several experimentally tested ways of implementing sound card photogates in detail, and we also provide a full-featured, free, open-source photogate software as a much more efficient experimentation tool than the usually used sound recording programs. Further information is provided in a dedicated page, www.noise.physx.u-szeged.hu/edudev

Random noise can help to improve synchronization of excimer laser pulses

Recently we have reported on a compact microcontroller-based unit developed to accurately synchronise excimer laser pulses (Robert Mingesz et al, Fluct. Noise Lett. 11, 1240007 (2012), DOI: 10.1142/S021947751240007X, arXiv:1109.2632). We have shown that dithering based on the random jitter noise plus pseudorandom numbers can be used in the digital control system to radically reduce the long-term drift of the laser pulse from the trigger and to improve the accuracy of the synchronisation. In this update paper we present our new experimental results obtained by the use of the delay controller unit to tune the timing of a KrF excimer laser as an addition to our previous numerical simulation results. The hardware was interfaced to the laser using optical signal paths in order to reduce sensitivity to electromagnetic interference and the control algorithm tested by simulations were applied in the experiments. We have found that the system is able to reduce the delay uncertainty very close to the theoretical limit and performs well in real applications. The simple, compact and flexible system is universal enough to be used in various multidisciplinary applications as well

Fluctuation enhanced gas detector for wireless sensor networks

Spontaneously produced Unfilled Pauses (UPs) andFilled Pauses (FPs) were played to subjects in an fMRI experiment. While both stimuli resulted in increased activity in the Primary Auditory Cortex, FPs, unlike UPs, also elicited modulation in the Supplementary Motor Area, Brodmann Area 6. This observation provides neurocognitive confirmation of the oft-reported difference between FPs and other kinds of speech disfluency and also could provide a partial explanation for the previously reported beneficial effect of FPs on reaction times in speech perception. The results are discussed in the light of the suggested role of FPs as floor-holding devices in human polylogs