Analysis of the EEG Rhythms Based on the Empirical Mode Decomposition During Motor Imagery When Using a Lower-Limb Exoskeleton. A Case Study

The use of brain-machine interfaces in combination with robotic exoskeletons is usually based on the analysis of the changes in power that some brain rhythms experience during a motion event. However, this variation in power is frequently obtained through frequency filtering and power estimation using the Fourier analysis. This paper explores the decomposition of the brain rhythms based on the Empirical Mode Decomposition, as an alternative for the analysis of electroencephalographic (EEG) signals, due to its adaptive capability to the local oscillations of the data, showcasing it as a viable tool for future BMI algorithms based on motor related events.by the Spanish Ministry of Science and Innovation, the Spanish State Agency of Research, and the European Union through the European Regional Development Fund in the framework of the project Walk—Controlling lower-limb exoskeletons by means of brain-machine interfaces to assist people with walking disabilities (RTI2018-096677-B-I00);and by the Consellería de Innovación, Universidades, Ciencia y Sociedad Digital (Generalitat Valenciana) and the European Social Fund in the framework of the project Desarrollo de nuevas interfaces cerebro-máquina para la rehabilitación de miembro inferior (GV/2019/009Authors would like to thank specially Kevin Nathan and the rest of the laboratory of JC-V for their help during the experimental trials and Atilla Kilicarslan for his help with the implementation of H∞ algorithm

Null detection using low resolution A/D converter

U tezi je rešavan centralni problem – detekcija nule dvobitnom stohastičkom digitalnom mernom metodom (SDMM). Formulisane su dve metode detekcije nule primenom dvobitne SDMM. Po prvoj metodi dinamička rezerva je oko 100 dB a po drugoj ne manje od 160 dB. Obe metode su proverene teorijski, simulaciono i eksperimentalno. Pored rešenja centralnog problema, dato je i nekoliko rešenja problema koji su sa njim vezani. Hipoteza ove teze – „dvobitna SDMM je u opsegu 0 % - 10% FS bolja od standardne sempling metode (SSM)“ – je potpuno potvrđena u svim razmatranim slučajevima.The main goal of this thesis was null-detection using a two-bit stochastic digital measurement method (SDMM). Two methods of null-detection, using two-bit SDMM, were formulated. Using the first method around 100 dB of dynamic reserve was achieved and using the second one no less than 160 dB. Both methods were theoretically, using simulation and experimentally confirmed. In addition to the solution of the main problem, several other related problems were also solved. The hypothesis of this thesis – “two-bit SDMM in range from 0 % - 10 % FS is better than the standard sampling method (SSM)” has been fully confirmed in all considered cases

Finansijski sistem i ekonomski rast

Finansijski sistem, kao integralni deo privrednog sistema, ima ključnu ulogu u povezivanju štednje i investicija. Stoga je nesporno važna uloga finansijskog sistema u funkcionisanju svake tržišne privrede. Osim mobilizacije i trnasfera štednje od finansijski suficitarnih ka finansijski deficitarnim subjektima, finansijski sistem uključuje funkcionisanje odgovarajućeg mehanizma kontrole korporativnog upravljanja, omogućava upravljanje rizicima imanentnim finansijskom poslovanju i olakšava razmenu dobara i usluga. Svaka od navedenih funkcija ima uticaj na akumulaciju kapitala i razvoj tehnoloških inovacija kao primarnih determinanti ekonomskog rasta. S druge strane, ekspanzija realnog sektora podrazumeva rast obima finansijskih transakcija. To dalje predstavlja osnovu za uvećanje obima i kvaliteta finansijskih proizvoda i usluga. Polazeći od različitih teorijskih modela i empirijskih rezultata, predmet istraživanja u doktorskoj disertaciji je međuzavisnost razvoja finansijskog sistema i ekonomskog rasta. S obzirom da su u tranzicionim privredama mehanizmi transfera finansijskih sredstava nedovoljno razvijeni, a tempo ekonomskog rasta spor, definisano područije istraživanja ima poseban teorijski i praktičan značaj. Shodno tome, osnovni cilj doktorske disertacije je da teorijsko-metodološki i empirijski sagleda vezu između razvoja finansijskog sistema i ekonomskog rasta. U doktorskoj disertaciji su najpre analizirani osnovni elementi finansijskog sistema. Predmet detaljne analize bile su funkcije finansijskog sistema koje objašnjavaju zbog čega se u svakoj privredi finansijskom sistemu pridaje izuzetna važnost. Analizirani su modeli finansijskog sistema, sa posebnim osvrtom na njihove prednosti i nedostake prilkom obavljanja osnovnih funkcija. Kao jedno od istraživačkih područja izdvajilo se pitanje determinanti i pokazatelja razvoja finasijskog sistema i ekonomskog rasta. Posebna pažnja posvećena je modelima koji dovode u vezu razvoj finansijskog sistema i ekonomski rast. Empirijskim istraživanjem na primeru Republike Srbije utvrđena je pozitivna korelacija između razvoja finansijskog posredovanja banaka i stope ekonomskog rasta. Takođe, otkrivena je jednosmerna kauzalna veza koja ide iz prvaca razvoja finansijskog posredovanja banaka ka stopi ekonomskog rasta. Otuda, smatra se opravdanim koncipiranje politika i strategija koje uključuju stimulisanje daljeg razvoja bankarskog sektora i podsticanje razvoja tržišta kapitala i nebankarskih finansijkih posrednika.The financial system, as an integral part of the economic system, plays a key role in linking savings and investment. Therefore, the role of the financial system in the functioning of every market economy is undoubtedly important. In addition to the mobilization and transfer of savings from entities with financial surplus to those with financial deficit, the financial system involves the functioning of appropriate corporate governance control mechanisms, enables risk management, imminent in financial operations, and facilitates the exchange of goods and services. Each of these functions has an impact on capital accumulation and development of technological innovation, as the primary determinants of economic growth. At the same time, the expansion of the real sector means increase in the volume of financial transactions. It stands for the basis for the increase in volume and quality of financial products and services. Starting from different theoretical models and empirical results, the research subject in the doctoral thesis is the correlation between financial system development and economic growth. Given that, in transition economies, mechanisms of funds transfer are insufficiently developed, and the pace of economic growth slow, the defined research area has special theoretical and practical significance. Consequently, the basic objective of the doctoral thesis is to, from the theoretical, methodological, and empirical aspects, examine the correlation between financial system development and economic growth. The doctoral thesis first analyzed the basic elements of the financial system. The subject of a detailed analysis referred to the functions of the financial system, which explain why each economy gives particular importance to the financial system. The analysis focused on the models of the financial system, with particular emphasis on their advantages and disadvantages in performing basic functions. The issue of determinants and indicators of financial system development and economic growth stood out as one of the research areas. Special attention was paid to models that connect financial system development and economic growth. Empirical research into the example of the Republic of Serbia established positive correlation between the development of financial intermediation by banks and economic growth rates. What is more, one-way causality from the development of financial intermediation by banks to the economic growth rate was revealed. Therefore, it is considered justifiable to design policies and strategies that include stimulating further development of the banking sector and encourage the development of capital markets and non-bank financial intermediaries

A novel EEG based linguistic BCI

While a human being can think coherently, physical limitations no matter how severe, should never become disabling. Thinking and cognition are performed and expressed through language, which is the most natural form of human communication. The use of covert speech tasks for BCIs has been successfully achieved for invasive and non-invasive systems. In this work, by incorporating the most recent discoveries on the spatial, temporal, and spectral signatures of word production, a novel system is designed, which is custom-build for linguistic tasks. Other than paying attention and waiting for the onset cue, this BCI requires absolutely no cognitive effort from the user and operates using automatic linguistic functions of the brain in the first 312ms post onset, which is also completely out of the control of the user and immune from inconsistencies. With four classes, this online BCI achieves classification accuracy of 82.5%. Each word produces a signature as unique as its phonetic structure, and the number of covert speech tasks used in this work is limited by computational power. We demonstrated that this BCI can successfully use wireless dry electrode EEG systems, which are becoming as capable as traditional laboratory grade systems. This frees the potential user from the confounds of the lab, facilitating real-world application. Considering that the number of words used in daily life does not exceed 2000, the number of words used by this type of novel BCI may indeed reach this number in the future, with no need to change the current system design or experimental protocol. As a promising step towards noninvasive synthetic telepathy, this system has the potential to not only help those in desperate need, but to completely change the way we communicate with our computers in the future as covert speech is much easier than any form of manual communication and control