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1

Design of Wearable EEG Device for Seizures Early Detection

Gaidar Viktoriia, Sudakov Oleksandr

International Journal of Electronics and Telecommunications

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2021

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Vol. 67, No. 2

187--192

EN

This paper presents the design of a wearable electroencephalography device and signal processing algorithm for early detection and forecasting of the epileptiform activity. The availability of the examination of functional brain activity for a prolonged period, outside of the hospital facilities, can provide new advantages in early diagnosis and intervention systems. In this study, the low-cost five-channel device is presented. The system consists of two main parts: the data acquisition and transmission units and processing algorithms. In order to create the robust epileptiform pattern recognition approach the application of statistical sampling and signal processing techniques are performed. The discrete wavelet and Hilbert-Huang transforms with principal component analysis are used in order to extract and select a low-dimension feature vector.

2

General concept of the EMG controlled bionic hand

Pieprzycki Adam, Król Daniel

Science, Technology and Innovation

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2020

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Vol. 8, no. 1

26--34

EN

The article presents a general concept of a bionic hand control system using multichannel EMG signal, being under development at present. The method of acquisition and processing of multi-channel EMG signal and feature extraction for machine learning were described. Moreover, the design of the control system implementation in the real-time embedded system was discussed.

3

Forecasting daily flow rate-based intelligent hybrid models combining wavelet and Hilbert–Huang transforms in the mediterranean basin in northern Algeria

Abda Z., Chettih M.

Acta Geophysica

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2018

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Vol. 66, no. 5

1131--1150

EN

The modelling of the rainfall–runoff relationship plays an important role in risk reduction and prevention against water-related disasters and in water resources management. In this research, we have modelled the rainfall–runoff relationship using intelligent hybrid models for forecasting daily flow rates of the Sebaou basin located in northern Algeria. As such, two hybrid approaches of artificial intelligence have been used in this study. These approaches are based on the adaptive neuro-fuzzy inference system combined with hydrological signal decomposition techniques. The first is derived from the Hilbert–Huang transform called the empirical mode decomposition and the other is derived from the discrete wavelet transform called multiresolution analysis. The results obtained seem to be very encouraging and the techniques appear promising. The performances of the hybrid models are relatively much higher than the other models used for comparison in this study. Although the technique of parallel computing has been used and despite the power of the computing station, the relatively long computation time is the main disadvantage of these models.

4

Analysis of the influence of friction force on the strains of gas pipeline using the Hilbert-Huang transform

Lepiarczyk D., Gawędzki W., Tarnowski J.

Tribologia

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2016

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nr 4

145--155

EN

The aim of the study was to determine the effect of friction forces on strains of a gas pipeline pipe in conditions of static and dynamic load. The experiments were conducted on a 28-metre section of pipe laid in quartz sand haunching. The source of dynamic loads was artificially generated soil vibration of a pulse character, which can be interpreted as seismic-like waves of mining origin. The static loads were applied by means of an actuator, which allowed the setting of different values of tension force acting along the pipe axis. The dynamic strain and vibration acceleration of the pipeline were measured during the experiments at different values of tension forces. The recorded signals were subjected to the time-domain decomposition by using the Hilbert-Huang transform. The method allows for the correct decomposition of the primary signal that describes the non-stationary and nonlinear phenomena as a sum of quasi-harmonic components whose amplitudes and frequencies are the parametric functions of time. The analysis included the determination of the influence of friction force in contact between the pipe and the sand haunching on the parameters of dynamic strain signals.

PL

Celem badań było określenie wpływu sił tarcia na stan odkształceń rury przesyłowej gazociągu w warunkach obciążenia statycznego oraz dynamicznego. Eksperymenty przeprowadzono na 28-metrowym odcinku rury ułożonej standardowo w gruncie w obsypce z piasku kwarcowego. Źródłem obciążeń dynamicznych rury przesyłowej w trakcie eksperymentów były wywoływane sztucznie drgania gruntu o charakterze impulsowym, które można interpretować jako fale parasejsmiczne pochodzenia górniczego. Obciążenia statyczne rury wywoływane były za pomocą siłownika, umożliwiającego zadawanie różnych wartości siły naciągu działającej wzdłuż jej osi. Podczas eksperymentów dla różnych wartości sił naciągu rury zmierzono sygnały dynamiczne jej odkształceń oraz przyspieszeń drgań. Zarejestrowane sygnały poddano dekompozycji w dziedzinie czasu z zastosowaniem transformacji Hilberta-Huanga. Metoda umożliwia poprawną dekompozycję sygnału pierwotnego na sumę quasi-harmonicznych składowych, których amplitudy oraz częstotliwości są parametrycznymi funkcjami czasu. W ramach analizy określono wpływ wartości siły tarcia w kontakcie rury z obsypką piaskową na wartości parametrów dynamicznych sygnałów odkształceń.

5

A new baroreflex sensitivity index based on improved Hilbert–Huang transform for assessment of baroreflex in supine and standing postures

Singh A., Saini B. S., Singh D.

Biocybernetics and Biomedical Engineering

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2016

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Vol. 36, no. 2

355--365

EN

The aim of this study is to propose a new baroreflex sensitivity (BRS) index using improved Hilbert–Huang transform (HHT) using weighted coherence (CW) criterion and apply it to assess baroreflex in supine and standing postures. Improved HHT is obtained by addressing the mode mixing and end effect problems associated with empirical mode decomposition which is a required step in the computation of HHT and thus mitigating the unwanted low frequency component from the power spectrum. This study was first performed on synthetic signals generated using integral pulse frequency model and further extended to real RR interval and systolic blood pressure records of 50 healthy subjects, 20 post acute myocardial infarction patients undergoing postural stress from supine to standing position. Evaluation is also performed on standard EuroBaVar database, comprising of 21 subjects, under supine and standing positions. The results are (i) enhanced values of supine-to-standing low frequency BRS index (α-LF) equal to 1.78 and high frequency BRS index (α-HF) equal to 2.48 are obtained using improved HHT compared to standard HHT (α-LF = 1.54, α-HF = 2.36) and traditional power spectral density (α-LF = 1.55, α-HF = 2.34) for healthy subjects, (ii) there is an increased rate of change of LF/HF power ratios from supine to standing positions, and (iii) number of BRS responses obtained using CW criterion are greater than those obtained by using mean coherence criterion. In conclusion, the new BRS index takes into consid-eration the non-linear nature of interactions between heart rate variability and systolic blood pressure variability.

6

Continuous wavelet and Hilbert-Huang Transforms applied for analysis of active and reactive power consumption

Avdakovic S, Bosovic A.

Metrology and Measurement Systems

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2014

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Vol. 21, nr 3

413--422

EN

Analysis of power consumption presents a very important issue for power distribution system operators. Some power system processes such as planning, demand forecasting, development, etc.., require a complete understanding of behaviour of power consumption for observed area, which requires appropriate techniques for analysis of available data. In this paper, two different time-frequency techniques are applied for analysis of hourly values of active and reactive power consumption from one real power distribution transformer substation in urban part of Sarajevo city. Using the continuous wavelet transform (CWT) with wavelet power spectrum and global wavelet spectrum some properties of analysed time series are determined. Then, empirical mode decomposition (EMD) and Hilbert-Huang Transform (HHT) are applied for the analyses of the same time series and the results showed that both applied approaches can provide very useful information about the behaviour of power consumption for observed time interval and different period (frequency) bands. Also it can be noticed that the results obtained by global wavelet spectrum and marginal Hilbert spectrum are very similar, thus confirming that both approaches could be used for identification of main properties of active and reactive power consumption time series.

7

Applying LCS to affective image classification in spatial - frequency domain

Lee P. -M., Hsiao T.-C.

Journal of Artificial Intelligence and Soft Computing Research

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2014

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Vol. 4, No. 2

99--123

EN

Recent studies have utilizes color, texture, and composition information of images to achieve affective image classification. However, the features related to spatial-frequency domain that were proven to be useful for traditional pattern recognition have not been tested in this field yet. Furthermore, the experiments conducted by previous studies are not internationally-comparable due to the experimental paradigm adopted. In addition, contributed by recent advances in methodology, that are, Hilbert-Huang Transform (HHT) (i.e. Empirical Mode Decomposition (EMD) and Hilbert Transform (HT)), the resolution of frequency analysis has been improved. Hence, the goal of this research is to achieve the affective image-classification task by adopting a standard experimental paradigm introduces by psychologists in order to produce international-comparable and reproducible results; and also to explore the affective hidden patterns of images in the spatial-frequency domain. To accomplish these goals, multiple human-subject experiments were conducted in laboratory. Extended Classifier Systems (XCSs) was used for model building because the XCS has been applied to a wide range of classification tasks and proved to be competitive in pattern recognition. To exploit the information in the spatial-frequency domain, the traditional EMD has been extended to a two-dimensional version. To summarize, the model built by using the XCS achieves Area Under Curve (AUC) = 0.91 and accuracy rate over 86%. The result of the XCS was compared with other traditional machine-learning algorithms (e.g., Radial-Basis Function Network (RBF Network)) that are normally used for classification tasks. Contributed by proper selection of features for model building, user-independent findings were obtained. For example, it is found that the horizontal visual stimulations contribute more to the emotion elicitation than the vertical visual stimulation. The effect of hue, saturation, and brightness; is also presented.

8

Application of Hilbert-Huang Transformation for Identifying the Fault Location on Series Compensated Lines

Kong X., Zhang Z, Yin X., Deng X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 5

135-140

EN

With the study on the transient state of series compensated lines under symmetrical and asymmetrical fault conditions, it’s obtained that low frequency component is much larger than aperiodic component of the measured transient current if the fault location is behind the series compensated capacitor. Due to the non-linear volt-ampere characteristics of MOV, the equivalent capacitive of series compensated device changes with time. Hence, the frequency of low frequency component caused by series compensated capacitor is time-varying. Hilbert-Huang Transformation is applied to analyze the instantaneous frequency and amplitude of the low frequency component to identify the fault location. The simulation results prove this method works.

PL

W artykule przedstawiono metodę lokalizacji awarii symetrycznych i niesymetrycznych w układach kompensacji szeregowej. Określono wpływ charakterystyki napięciowo-prądowej łącznika warystorowego na wartość harmonicznych niższego stopnia, wprowadzanych do sieci. Zastosowano transformację Hilbert-Huang w celu analizy chwilowej częstotliwości i amplitudy składowej niskiej częstotliwości oraz określenia miejsca awarii. Wykonano badania symulacyjne.

9

Wykorzystanie transformacji Hilberta-Huanga do detekcji spalania stukowego w silnikach benzynowych

Fiołka J.

Elektronika : konstrukcje, technologie, zastosowania

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2013

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Vol. 54, nr 10

67-69

PL

Spalanie stukowe, występujące w silnikach o zapłonie iskrowym, związane jest z nieprawidłowym przebiegiem procesu spalania mieszanki paliwowo-powietrznej. Zjawisko to, wywołane samozapłonem części mieszanki, powoduje gwałtowny wzrost ciśnienia i temperatury w komorze spalania. Ponadto, obserwujemy wzrost drgań bloku silnika, a także charakterystyczny dźwięk (tzw. stuk). Częste występowanie zjawiska pogarsza sprawność jednostki napędowej oraz zużycie paliwa, a także może prowadzić do uszkodzenia silnika. W artykule zaprezentowano metodę detekcji spalania stukowego opartą na transformacji Hilberta-Huanga. To stosunkowo nowe narzędzie analizy pozwala na dekompozycję wieloskładnikowego niestacjonarnego sygnału na poszczególne składowe. Analizując w ten sposób sygnał ciśnienia, uzyskujemy precyzyjną informację o przebiegu procesu spalania mieszanki paliwowo-powietrznej.

EN

Knocking combustion in spark ignition engines is associated with abnormal combustion of the air-fuel mixture. This phenomenon, caused by the auto-ignition of the mixture, results in a rapid increase in pressure and temperature in the combustion chamber. Moreover, a characteristic „pinging” sound and vibrations of the engine block are observable. Heavy knocking deteriorates the efficiency of the engine, fuel economy and can lead to the engine damage. The paper presents a knock detection method based on Hilbert-Huang transform. This relatively new tool allows the decomposition of a multicomponent nonstationary signal into individual components. Applying this method to the pressure signal, we are able to obtain a precise informationa about the cobustion process.

10

Zastosowanie transformaty Hilberta-Huanga do przetwarzania sygnału z przepływomierza wirowego

Wójcik A., Pankanin G.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 10a

37-45

PL

Praca związana jest z problematyką przetwarzania sygnału pomiarowego z przepływomierza wirowego. W szczególnych konstrukcjach i sytuacjach pomiarowych sygnał może być słabej jakości. W pracy opisano algorytm dekompozycji empirycznej sygnału i analizę spektralną wyekstrahowanej składowej podstawowej. Przeprowadzono badania empiryczne, które wykazały efekt mieszania się częstotliwości. Zastosowany zmodyfikowany algorytm pozwolił na eliminację wpływu tego efektu na wynik przetwarzania.

EN

The work is related to the problem of the vortex flowmeter signal processing. In specific flowmeter designs and measurement circumstances, the signal might be weak. Algorithm of empirical decomposition of the signal and spectral analysis of extracted fundamental component has been described. The effect of frequency mixing has been observed in empirical investigations. Due to modified algorithm application, suppression ofthis effect has been attained.(Hilbert-Huang transform application in vortex meter signal processing)

11

Power line fault location using the Complex Space-Phasor and Hilbert-Huang Transform

Bernadić A., Leonowicz Z.

Przegląd Elektrotechniczny

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2011

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R. 87, nr 5

204-207

EN

Fault location finding in power system is very important problem in power system monitoring. Moreover, demand for high grid availability are crucial for TSOs contracts. Many scientific papers are published on mentioned theme, along with efforts in transmission and distribution system operators about improving fault location accuracy. Recently, signal processing methods like Wavelets and Hilbert-Huang Transform are introduced in fault location procedure. In this paper, a new approach to power system fault signal processing is proposed. Three-phase fault voltages are converted to the vector of absolute values of its complex-space phasor. This vector represents fault traveling wave and it is further processed for fault location finding with Hilbert-Huang transform. The simulation results show that proposed method allows better accuracy in comparison to earlier procedures.

PL

Lokalizacja zwarć w liniach przesyłowych jest ważna z punktu widzenia prawidłowego funkcjonowania linii przesyłowych. W ostatnim czasie zaproponowano wiele metod lokalizacji zwarć za pomocą falek czy transformaty Hilberta-Huanga. W tym artykule proponujemy przekształcenie trójfazowych sygnałów napięciowych za pomocą wektora przestrzennego. Rezultaty symulacji wykazują poprawę dokładności lokalizacji zwarć tą metodą w porównaniu z wcześniej opisanymi algorytmami.

12

An application of Hilbert-Huang transform and principal component analysis for diagnostics of cylindrical plunge grinding process

Lajmert P.

Journal of Machine Engineering

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2010

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Vol. 10, No. 1

39--49

EN

This paper presents a sensor based diagnostic system for a cylindrical plunge grinding process which ensures a reliable process state and tool wear identification. A new signal processing technique, i.e. Hilbert-Huang transform (HHT) was evaluated for this purpose based on the vibration and acoustic emission signal measurements. Numerical and experimental studies have demonstrated that the process state and tool wear may be effectivel detected through a statistical analysis of the time-dependent amplitudes and instantaneous frequencies resulting from the HHT. A principal component analysis was used to diagnose different grinding process states.

13

Use of Hilbert-Huang transform of a vibroacoustic signal in the research related to the gigacycle fatigue process

Gontarz S., Jasiński M., Radkowski S.

Diagnostyka

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2009

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nr 4(52)

85-92

EN

The purpose of this paper is to develop, for highly-resistant materials, a method of forecasting and analysis of gigacycle fatigue durability (108-109 cycles) relying on vibroacoustic signal analysis. The proposed method involves use of results of vibroacoustic signal analysis obtained during accelerated fatigue tests conducted in dedicated test bed constructed specially for this purpose and operating in the frequency range of 10 kHz which corresponds to the resonance frequency of vibration of samples. Let us note that the process of defect formation may lead to both, the intensification of non-linear phenomena as well as the occurrence of non-stationary effects even if during the early stages the intensity of defects is small while the growth of the level of vibration and noise is negligible, as contrasted with emergency states. A useful method is to test the higher order spectra, which respectively define the non-linear effects. The conducted analyses point to high usability of Hilbert spectrum through the EMD examining the non-stationary character of signals. The main goal of these investigations is to examine the signal processing method for gigacycle fatigue durability and impact of dynamic stress. Efficient signal analysis would be especially important for high frequency loading which dominates in rotating machinery diagnosis.

PL

Celem pracy jest opracowanie, dla materiałów o wysokiej wytrzymałości, metody prognozowania i analizy gigacyklowej trwałości zmęczeniowej (108-109 cykli) na podstawie badania sygnału wibroakustycznego. W metodzie proponuje się wykorzystać wyniki analizy sygnału wibroakustycznego, uzyskiwane podczas przyspieszonych badań zmęczeniowych, prowadzonych na specjalnie do tego celu skonstruowanym i zbudowanym stanowisku badawczym, pracującym w zakresie częstotliwości rzędu 10 kHz, odpowiadającym częstotliwości drgań własnych próbek. Zauważono, że proces kształtowania się uszkodzenia może prowadzić zarówno do nasilenia zjawisk nieliniowych jak również do wystąpienia efektów niestacjonarnych nawet wtedy, kiedy podczas wczesnych stadiów uszkodzeń ich intensywność jest mała a wzrost poziomu drgań i szumu jest pomijalny, porównując go z poziomem przy stanach zagrożenia. Użyteczna jest w tym wypadku metoda widm wyższego rzędu, która odpowiednio definiuje efekty nieliniowe. Zamieszczone w publikacji analizy wskazują na dużą użyteczność widm Hilberta a w szczególności empirycznej dekompozycji sygnału (EMD), która pozwala na analizę niestacjonarnego charakteru sygnału. Głównym celem badań było znalezienie skutecznej metody przetwarzania sygnałów dla gigacyklowych wytrzymałościowych procesów zmęczeniowych oraz zbadanie wpływu obciążeń dynamicznych. Efektywny sposób analizy sygnału jest szczególnie ważny w diagnostyce maszyn obrotowych gdzie występują wysoko częstotliwościowe obciążenia.