Artur Polinski

Gdansk University of Technology · Department of Biomedical Engineering

Objective: The aim of the study is to investigate the effect of the signal sampling frequency and low-pass filtering on the accuracy of the localisation of the fiducial points of the photoplethysmographic signal (PPG), and thus on the estimation of the blood pressure (i.e. the accuracy of the estimation). Approach: Statistical analysis was perfo...

Respiration-induced signals contain a clinically significant information. It could be obtained utilizing both direct and indirect methods. ECG-Derived Respiration (EDR) method is the latter one. However, in this case, two approaches could be distinguished. First one is based on determining changes in the morphology of QRS complexes while the second...

We consider the differential–algebraic system for the blood flow and pressure in the systemic arteries. By the operator splitting method, we transform the system into the hyperbolic one, introduce the bicharacteristics, and perform the time–space nonuniform discretization, obtaining the innovative difference scheme. Our results are illustrated with...

A wearable system for monitoring non-invasively signals invaluable when examining person suffering from vasovagal syncope is presented in the paper. Following signals are continuously recorded: electrocardiogram, photopletysmogram, impedance cardiogram and electrodermal resistance.

An unobtrusive, noninvasive and continuous pressure measurement is invaluable however, still being under research and development. There are many attempts proposing an appropriate relationship between pulse pressure velocity and pressure. Fifteen different formulas, both theoretical and experimental, describing relation between blood pressure and c...

The paper presents a preliminary meta-analysis of the sample correlation between pulse arrival time (PAT) and blood pressure (BP). The aim of the study was to verify sample correlation coefficient between PAT and BP using an affine model $ BP = a . PAT+b $ for systolic and diastolic blood pressure. The databases included in the search were the IEEE...

An influence of a human body position on ECG derived respiration (EDR) signal is presented in the paper. Examinations were performed during deep, suspended and normal breathing for eight people in four different body positions. EDR and thoracic impedance signals were compared using correlation and standard deviation coefficients. Obtained results h...

In this paper we deal with the problem of precise gesture recognition for the active optical proximity sensor with sparse 8 photodiodes. We particularly focus on developing the method of estimating the real, usually not observable, maximum signal value representing maximum intensity of light reflected from an obstacle present in the front of the se...

In this paper we investigate the effectiveness of the interaction using eye tracking and electromyography. Smart glasses requires reliable interfaces for controlling the graphic content displayed directly in front of the user's eye. Presented research is related with the eGlasses project, which is focused on the development of an open platform in t...

In this paper a novel application of inductive proximity sensors for detection of living tissue by means of measurements of the coil impedance changes at different frequencies is described. The mathematical analyses utilizing Bessel function estimation include detected object size and its distance from a sensor. The main aim of this study is to pro...

This paper presents the algorithm for validation of electrodes locations for the thoracic impedance measurements. In particular the presented algorithm was designed to perform the telemetric sleep apnea monitoring. One of the problems, during the clinical tests of a developed device, was to preserve the repeatability of measurements. It strongly de...

The phenomenon of thermal ablation is described by Pennes’ bioheat equation. This model is based on Newton’s law of cooling. Many approximate methods have been considered because of the importance of this issue. We propose an implicit numerical scheme which has better stability properties than other approaches.

Obstructive sleep apnea (OSA) is a condition of cyclic, periodic obstruction (stenosis) of the upper respiratory tract. OSA could be associated with serious cardiovascular problems, such as hypertension, arrhythmias, hearth failure or peripheral vascular disease. Understanding the way of connection between OSA and cardiovascular diseases is importa...

An influence of an electrode-array configuration on an impedance signal composition for a fixed spatial distribution of its sources is examined in the paper. The Finite Element Method and Geselowitz relationship were used for examining three different electrode-arrays. A sensitivity approach was used to evaluate each configuration assuming that loc...

The paper presents a novel approach to assessment of ventricular dyssynchrony basing on multichannel electrical impedance measurements. Using a proper placement of electrodes, the sensitivity approach allows estimating time difference between chambers contraction from over determined nonlinear system of equations. The theoretical considerations whi...

We consider Pennes’ bioheat equation and discuss an implicit numerical scheme which has better stability properties than other approaches. Our discussion concerns Carthesian geometry problems, however it carries over to spherical geometry models and more complicated shapes.

Disorders of the heart and blood vessels are the leading cause of health problems and death. Early detection of them is extremely valuable as it can prevent serious incidents (e.g. heart attack, stroke) and associated complications. This requires extending the typical mobile monitoring methods (e.g. Holter ECG, tele-ECG) by introduction of integrat...

Health monitoring at home could be an important element of the care and support environment for older people. The diversity of diseases and different needs of users require a universal design of a home platform. We present our work on a sensor-based multimodal platform which is designed to recognize the activities an elderly person performs in thei...

The paper presents an analysis of correlation between heart rate (HR) and blood pressure (BP). The actual data were obtained from three female and one male. The systolic and diastolic blood pressure was measured with the invasive method in the radial artery. The correlation coefficient indicates only linear dependence, so the inverse of HR was also...

This article presents the tryout of increasing computer and internet security by means of complementing the authentication procedure with the gaze tracking. The eyes of the person who is being identified follow the point on the computer screen and eye movement tracking system is used to collect information about eye movements during the experiment....

Recently, an attempt to monitor elders, disabled and/or convalescent people at home has been an emerging discipline of technology and science. Especially, providing a home care based on remote sensing for single and elder persons is a challenging task. An integrated sensor for cardiac, breathing and kinetics of movement activities is developed. It...

A design of an ergonomic and user-friendly pointing device for elderly people enabling them to operate a traditional windows-based operating system is presented in the paper. To mimic a more natural way of pointing at various things on the computer screen the traditional interface was combined with the gaze control pointing device. The gaze trackin...

In this paper methods for image simulation as seen by a color blinded and a method for constructing images of perceived color difference are presented. The work is also focused on the interactive color description of an image contents. As a result, the individuals having problems with color discrimination can identify colors in an image.

The aim of our study was the evaluation of a pressure prediction method, which was based on Taylor series. The pressure value was predicted basing on its past values, which were weighted by coefficients calculated according to the Taylor series approximation. The advantage of such approach was possibility of non-uniform pressure measurements. The m...

The paper presents a novel method for improving the reliability of impedance spectroscopy. This is achieved by combining the least squares (LS) method and Kramers- Kronig (KK) transforms when estimating the parameters of the measured sinusoidal response. The simplest idea in spectroscopy measurement is to use LS approximation at each measurement fr...

We study the initial-value problem for parabolic equations with time dependent coefficients and with nonlinear and nonlocal right-hand sides. Nonlocal terms appear in the unknown function and its gradient. We analyze convergence of explicit finite difference schemes by means of discrete fundamental solutions.

This paper presents the construction of a six-ring probe for monitoring immittance changes. The spatial sensitivity of the probe is defined. This is used to examine the uniqueness of the probe in terms of its application to monitoring conductivity changes. A spatial distribution of the sensitivity is presented for isotropic and anisotropic cases. T...

The paper considers the contribution of conductivity changes undergone in an anisotropical medium to measured resistance. This was achieved by extending the relationship proposed by Geselowitz to anisotropical materials described, therefore, by a conductivity tensor. It was found that each element of a conductivity change tensor contributed to the...

This paper presents the construction of a probe for immittance spectroscopy. The probe is based on the four-electrode technique. The current application electrodes are long parallel strips and have been partitioned into three segments to measure the immittance of relatively small volumes. The probe constant has been calculated assuming anisotropy o...

The paper presents an application of Electrical Impedance Tomography to detect a buried object. This application leads to the inverse problem of EIT on an unbounded domain. Here a bounded domain was used instead of an unbounded one. This domain was divided into three regions in such way that the potential distribution was unchanged when compared to...

This paper considers the applicability of effective conductivity measurements for monitoring physiological and/or pathological phenomena induced by ischemia in the myocardium. The sensitivity of a probe, calculated by means of the finite element method, to changes in the conductivity of the tissue examined is defined for this purpose. Probes develo...

Comparison of main construction of sensing probes for measurements of electrical properties of living tissues is presented. Original solution giving very good results in a broad range of frequency is described.

The construction of the cell for measurement of complex electric conductivity is described. Two-chamber and four-electrode system with temperature stabilisation is developed. Guarding chamber and electrodes are used to minimise the leakage of current from the measurement chamber. The cell construction is examined by use of Finite Element Method. Th...

The multifrequency impedance plethysmograph is achieved by sequentially changing the drive current and measuring the resultant voltages at each frequency. The change in frequency is made so fast that physiological events are considered steady. The measured voltage is demodulated digitally

A three-dimensional finite element model of the thorax and neck was constructed to investigate the influence of the lungs conductivity on relations between the impedance changes associated with various physiological events during systole. It has been found that these relations depend strongly on lungs' conductivity. This dependence has been verifie...

A FEM has been used to examine influence of tissues' conductivities and electrodes' array configurations on the results obtained by Impedance Cardiography. A Geselowitz's relationship has been applied to estimate partial contributions from each region of thorax. The obtained results have indicated the strong dependence of ICG signal on factors ment...