Wyniki wyszukiwania dla: PROBES , BANDWIDTH , COHERENCE , CORRELATION , FREQUENCY MEASUREMENT , TRANSFER FUNCTIONS , BASEBAND
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On adaptive covariance and spectrum estimation of locally stationary multivariate processes
PublikacjaWhen estimating the correlation/spectral structure of a locally stationary process, one has to make two important decisions. First, one should choose the so-called estimation bandwidth, inversely proportional to the effective width of the local analysis window, in the way that complies with the degree of signal nonstationarity. Too small bandwidth may result in an excessive estimation bias, while too large bandwidth may cause excessive...
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Effect of Temperature and Nanoparticle Concentration on Free Convective Heat Transfer of Nanofluids
PublikacjaA theoretical analysis of the influence of temperature and nanoparticle concentration on free convection heat transfer from a horizontal tube immersed in an unbounded nanofluid was presented. The Nusselt (Nu) number and heat transfer coefficient were parameters of the intensity of the convective heat transfer. For free convection, the Nu number was a function of the Rayleigh (Ra) number and Prandtl (Pr) number. The Rayleigh (Ra)...
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Radioisotope measurements of the liquid-gas flow in the horizontal pipeline using phase method
PublikacjaThe paper presents application of the gamma-absorption method to a two-phase liquid-gas flow investigation in a horizontal pipeline. The water-air mixture was examined by a set of two Am-241 radioactive sources and two NaI(Tl) scintillation probes. For analysis of the electrical signals obtained from detectors the cross-spectral density function (CSDF) was applied. Results of the gas phase average velocity measurements for CSDF...
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The influence of microjet array area ratio on heat transfer in the compact heat exchanger
PublikacjaThe paper describes the comprehensive study on the effect of microjet array geometrical parameters on the heat transfer enhancement in the modular heat exchanger. The conducted experimental study provides an experimental database on single phase submerged microjet heat transfer. The Wilson plot method was applied to determine the heat transfer coefficients in the laminar and transition flow regimes of a liquid-to-liquid heat exchanger....
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Design of Microwave-Based Angular Displacement Sensor
PublikacjaThis letter presents a novel microwave-based rotation sensor having a wide dynamic range to detect and measure the angular displacement in terms of the change in resonant frequency. The proposed sensor is based on the microstrip technology, where a rotor comprised of a complementary splitring resonator (CSRR) placed on the ground plane of the microstrip line is free to rotate around its axis. The mechanical rotation of CSRR determines...
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Refractive index measurement in the range of 1.3 – 1.5 for 1550 nm wavelength (2nd serie)
Dane BadawczeThe low-coherence refractive index measurements of certified liquid samples provided by Cargille Labs were performed. The measurement system consisted of a broadband light source (central wavelength of 1550 nm), an optical spectrum analyzer, a 2x1 fiber-optic coupler (50:50 power split), and single-mode telecommunication optical fibers. A micromechanical...
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Refractive index measurement in the range of 1.3 – 1.5 for 1550 nm wavelength (1st serie)
Dane BadawczeThe low-coherence refractive index measurements of certified liquid samples provided by Cargille Labs were performed. The measurement system consisted of a broadband light source (central wavelength of 1550 nm), an optical spectrum analyzer, a 2x1 fiber-optic coupler (50:50 power split), and single-mode telecommunication optical fibers. A micromechanical...
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A novel method of time-frequency analysis: an essential spectrogram
PublikacjaA novel precise method of time-frequency analysis is presented. In the algorithm, a new energy distribution is estimated by simultaneously discard or displacement of the classical spec- trogram energy. A channelized instantaneous frequency and a local group delay are used in order to replacement in the same manner as formulated by Kodera et al. [1, 2]. Additionally, new representations: a channelized instantaneous bandwidth and...
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Usage of concentrated spectrogram for analysis of acoustical signals
PublikacjaA novel precise method of signal analysis in the time-frequency domain is presented. A signal energy distribution is estimated by discard and displacement of energy parts of the classical spectrogram. A channelized instantaneous frequency and a local group delay are used in order to energy replacement. Additionally, newly introduced representations such as: a channelized instantaneous bandwidth and a local group duration are used...
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Design of a Patch Power Divider with Simple Structure and Ultra-Broadband Harmonics Suppression
PublikacjaThis paper introduces a simple H-shaped patch Wilkinson power divider (WPD), which provides ultra wide harmonics suppression band. The presented WPD designed at 1.8 GHz, and exhibits good performance at the operating bandwidth. In the proposed divider structure, two simple patch low-pass filters (LPFs) are employed at each branch, and three open ended stubs are added at each port. The proposed divider, implemented using the aforementioned...
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Optimal ECG lead for deriving respiratory signal
PublikacjaEDR is an interesting measuring technique that allows an indirect assessment of respiratory activity. This is an alternative solution to direct methods that are based on the measurement of air flow, which require a specialized sensor or even a system. However, due to inter-personal anatomical differences, the optimal ECG lead (placement of the electrodes) ensuring the best EDR signal quality is not fixed. An influence of ECG lead...
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Simulation of the weight averaging of pulse frequency modulated sensor output signal
Dane BadawczeThe aim of the research is investigation of the efficiency of weight averaging of pulse frequency modulated signal. It was shown that from the point of view of the reduction of the sampling error the best are polynomial weighing functions, for which the maximum of this component error decreases proportionally to the appropriate power of the number of...
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Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublikacjaThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
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Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems
PublikacjaTwo examples of microwave devices, fed by a coplanar waveguide and realized on a thin substrate (or without such a substrate), are employed to investigate the influence of devices’ curvatures and the proximity of different materials on their parameters. To perform the tests, a broadband antenna and a low-pass filter are chosen. A feeding coplanar waveguide is realized on a dielectric material brick attached to an SMA connector...
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Co-simulation strategy of transient CFD and heat transfer in building thermal envelope based on calibrated heat transfer coefficients
PublikacjaThe paper presents a strategy to develop a fully transient numerical model of a heat transfer in building, using a transient CFD model of indoor air and a thermal envelope model, running in a co-simulation. The strategy relies on the utilization of RANS with a high-Re turbulence model and a wall function, which enables to use a coarse computational mesh limiting the computational time. Since wall functions give invalid heat transfer...
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Novel fast non-linear electrochemical impedance method for corrosion investigations
PublikacjaThe paper presents a novel approach to corrosion rate monitoring using non-linear electrochemical impedance spectroscopy. The authors propose a new variant of non-linear impedance measurement using amplitude-modulated multi-frequency ac perturbation signal. It allows shortening of measurement duration so it is possible to monitor corrosion rate of the systems experiencing rapid changes. In this way a limitation resulting from lack...
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Rapid Re-Design and Bandwidth/Size Trade-Offs for Compact Wideband Circular Polarization Antennas Using Inverse Surrogates and Fast EM-Based Parameter Tuning
PublikacjaDesign of compact wideband circularly polarized (CP) antennas is challenging due to the necessity of simultaneous handling of several characteristics (reflection, axial ratio, gain) while maintaining a small size of the structure. Antenna re-design for various operating bands is clearly more difficult yet practically important because intentional reduction of the bandwidth (e.g., by moving the lower edge of the operating band up...
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Experimental investigations on heat transfer enhancement in shell coil heat exchanger with VARIABLE Baffles GEOMETRY
PublikacjaThe paper presents the possibility of using passive intensification of heat transfer in the form of baffles to increase the energy efficiency of the shell and coil heat exchanger. The experiment was carried out by using a modular coil heat exchanger in the form of an electric heater. Water was used as a working fluid with constant thermal-flow parameters at the inlet of the module. It should be noted that experiments were made...
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Testing the impact of simplifications adopted in models describing wave loads on ship
PublikacjaThe wave-ship system in naval architecture is generally assumed to be a linear one. This allows for the computation of a transfer function of ship response to waves including wave loads on ship. The transfer function and the wave spectral density function enable the development of the stochastic process of wave loads on ship, corresponding to the irregular wave generating that loads. If the mathematical models of wave load transfer...
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Structural optimization of microjet array cooling system
PublikacjaThe single phase heat transfer from an upward facing, horizontal copper surface to arrays of impinging water jets was experimentally investigated. Experimental configuration allows for a free-surface unconfined jets flow. Square nozzles 50 × 100 μm arranged in four different geometries were used. Additionally, for the set of two jets array geometry was varied by adjusting the nozzle to nozzle distance. The area averaged heat transfer...
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
PublikacjaAn innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance...
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The evaluation of the vibration measurement usability of electronic indicator lemag "premet C"
PublikacjaThe measuring possibilities of modern compression and combustion pressure analyzers are extended with additional functions. One of them is parallel to the pressure measurement, the measurement of vibrations in the region of the cylinder head. The paper presents a general assessment of the vibration measurement function of the electronic indicator LEMAG "PREMET C". This feature is very rarely offered by manufacturers of these devices....
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SPECTRAL DYNAMIC ANALYSIS OF A STATIONARY JACK-UP PLATFORM
PublikacjaThe paper refers to the dynamic short-term response analysis of the Baltic steel drilling platform (see Fig.2) in a random sea-state represented by one-dimensional wave spectrum proposed by Striekalov and Massel and it is recommended for the Baltic Sea area. The Baltic drilling platform is a jack-up type platform for the exploration and exploitation of oil under the Baltic Sea. The analysis presented deals with the stationary...
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Novel structure and design of enhanced-bandwidth hybrid quadrature patch coupler
PublikacjaA novel structure and design optimization procedure of an enhanced-bandwidth hybrid quadrature patch coupler is proposed. Improved performance of the circuit has been obtained by parameterizing the coupler sections using splines, which introduces additional degrees of freedom. Due to computational complexity of the parameter adjustment problem, a sequential design procedure is applied. In each iteration, a selected number of spline...
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Metamaterial-Based Series-Fed Antenna with High Gain and Wideband Performance for Millimeter Wave Spectrum Applications
PublikacjaThis paper presents a high-gain, wideband series-fed antenna designed for 5G millimeter-wave (MMW) applications. The structure employs a substrate-integrated waveguide (SIW)-based power splitter and metamaterials (MMs). The power divider functions effectively at 27.5 GHz, exhibiting an impedance bandwidth from 26.9–28.6 GHz. The series-fed dipole is assembled on the SIW-based power splitter, incorporating four dipoles with varying...
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Measurements of relative frequency instability
PublikacjaFrequency constancy can be determined by the change in time for the subsequent periods. The article shows that classical the method of digital period measurement is not suitable for the measurement process. Therefore, a method using an integrating circuit is being proposed. Errors in the measurement of the given method have been analyzed.
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Measurements of ultrasonic bulk and guided wave propagation in additively manufactured cubes and plates obtained by ultrasonic pulse velocity analyzer and scanning laser vibrometry
Dane BadawczeThe DataSet contains the results of measurements of ultrasonic wave propagation in additively manufactured samples made of polylactic acid (PLA). Three types of raster angles in two consecutive layers were assumed: 0°/90° (#1), 45°/-45° (#2) and 90°/90° (#3) with respect to the x-axis. For each printing variants a cubic sample (#C1-3) with dimensions...
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The experimental results of sorption cycles
Dane BadawczeExperimental studies of sorption cycles were carried out using a prototype research stand, which is a laboratory-scale model of an adsorption chiller. The Intensified Heat Transfer Adsorption Bed (IHTAB) reactor is adapted to the analysis and optimization of various parameters of adsorption systems, e.g., constructions and compositions of adsorption...
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Advanced Sensor for Non-Invasive Breast Cancer and Brain Cancer Diagnosis Using Antenna Array with Metamaterial-Based AMC
PublikacjaMicrowave imaging techniques can identify abnormal cells in early development stages. This study introduces a microstrip patch antenna coupled with artificial magnetic conductor (AMC) to realize improved sensor for non-invasive (early-stage) breast cancer and brain cancer diagnosis. The frequency selectivity of the proposed antenna has been increased by the presence of AMC by creating an additional resonance at 2.276 GHz associated...
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Improved Bandwidth of Microstrip Wide-Slot Antenna Using Gielis Curves
PublikacjaThe development of a broadband printed wide-slot antenna based on Gielis curves is presented in this article. The printed wide-slot antenna can be conveniently reshaped to achieve ultra-wideband performance by using superformula. The distinct advantage of employing the superformula in design of wide-slot antenna lies in its ability to define nearly any geometric shape including non-standard, complex and non-intuitive for the wide-slot...
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Synthesis of coupled lossy resonator filters.
PublikacjaA technique for fast synthesis of coupling matrix low-pass prototypes of generalized. Chebyshev bandpass filters with lossy resonators is presented in this letter. The coupling matrix is found by solving a nonlinear least squares problem based on zeros and poles of filter's transfer functions.
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Niskokoherencyjne czujniki światłowodowe wykorzystujące cienkowarstwowe struktury nanodiamentowe
PublikacjaZnaczny rozwój technologii wytwarzania czujników światłowodowych spowodował, że są one powszechnie dostępne i stosowane w wielu gałęziach przemysłu, nauki oraz medycyny. Zastosowanie nowych materiałów w konstrukcji takich czujników niesie za sobą duży potencjał. Celem rozprawy jest przedstawienie możliwości wykorzystania cienkowarstwowych struktur nanodiamentowych w niskokoherencyjnych czujnikach światłowodowych, które poprawią...
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Long-term measurement of physiological parameters - adult (120 minutes)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (120 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters.
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 90 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - child (60 minutes)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - child (3)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters (4)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 90 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - child (4)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 120 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - adult (1)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 120 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters (3)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 90 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - child (2)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 120 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters (2)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 90 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - child (1)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (up to 110 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (60 minutes) 3 serie
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (60 minutes) 6th serie
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (60 minutes) 5 serie
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (60 minutes) 1 serie
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (60 minutes) 12. series
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (60 minutes) measurement of physiological parameters was performed on the healthy...
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Long-term measurement of physiological parameters - a teenager (4h)
Dane BadawczeThe data set was obtained during the project focus on the determination of changes in physiological parameters due to a stressful situation.The measurements were conducted with the system which consists e.g. sensors of temperature, skin resistance, and pulse.Long-term (4 hours) measurement of physiological parameters was performed on the healthy volunteer...