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Magnetic effects on thermocouples (2014)

BEGUŠ, Samo, BOJKOVSKI, Jovan, DRNOVŠEK, Janko, GERŠAK, Gregor.
Measurement science & technology; 2014; Vol. 3, no. 25; str. 1-11

Thermometers in laboratory environment and industrial applications are often subject to extraneous, usually unwanted and uncontrolled magnetic fields. The goal of this paper was to analyse and empirically and experimentally prove the magnetic sensitivity of thermocouples exposed to low magnetic fields: both dc and ac. The magnetic effect on ferromagnetic and non-ferromagnetic thermocouples at liquid-nitrogen-boiling point (−196 °C), ice point (0 °C), in water (17 °C) and at melting point of gallium fixed point cell (29.7646 °C) was investigated.

A large aperture blackbody bath for calibration of thermal imagers (2013)

MIKLAVEC, Andraž, PUŠNIK, Igor, BATAGELJ, Valentin, DRNOVŠEK, Janko.
Measurement science & technology; 2013; Vol. 2, no. 24; str. 1-8;

This paper describes the problem of thermographic cameras, which are widely used for accurate measurement of temperature and not just temperature differences, which is more easy. To provide accurate and reliable measurements it is necessary to calibrate the thermal imaging camera, which allows assessment of the entire field of vision. To this end, we created a black body with a large opening, which has better temperature stability and homogeneity as the temperature sensitivity of the detector thermal imaging cameras.

A procedure for evaluation of non-invasive blood pressure simulators (2009)

GERŠAK, Gregor, ŽEMVA, Aleš, DRNOVŠEK, Janko.
Medical & biological engineering & computing; 2009;Vol. 47, no. 12; str. 1221-1228

In scope of research and development activities in the field of medical measuring instrumentation, we developed a procedure for evaluation of noninvasive blood pressure patient simulators, which enable reliable and repeatable testing of oscillometric automatic non-invasive blood pressure devices.

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Estimation of parameters of the weakly damped sinusoidal signals in the frequency domain (2011)

AGREŽ, Dušan.
Estimation of parameters of the weakly damped sinusoidal signals in the frequency domain. Computer standards & interfaces, ISSN 0920-5489. [Print ed.], Feb. 2011, vol. 33.

In this paper, exponentially damped sinusoidal signals are analyzed. Simple algorithms for fast measurement and estimation of the unknown damping, frequency, amplitude and phase are presented. The peaks of the discrete Fourier transform (DFT) results are adopted to obtain the parameters. The concept of quotient interpolation using the Hann window for the basic three parameters is also adopted for the damping estimation. In the case of the weakly damped sinusoids with dumping values up to 1, using the rectangular window in the estimation reduces the systematic errors in comparison with the Hann window, especially in the vicinity of the coherent sampling conditions.

Affective labeling in a content-based recommender system for images (2013)

TKALČIČ, Marko, ODIĆ, Ante, KOŠIR, Andrej, TASIČ, Jurij F.
Affective labeling in a content-based recommender system for images. IEEE transactions on multimedia, ISSN 1520-9210. [Print ed.], Feb. 2013

Pretekle raziskave so pokazale izboljšanje priporočilnih sistemov, ko so, poleg žanra, bile uporabljene še emotivne značke. Te značke lahko pridobimo na dva načina, ki imata svoje prednosti in slabosti: na ekspliciten način (natančne značke, vsiljivost sistema, počasnost) ali impliciten način (nenatanče značilke, a uporabniku skrito in prijazno). V tem članku smo opravili primerjavo vsebinskega priporočilnega sistema ki uporablja eksplicitni in implicitni način pridobivanja značilk. Rezultati so pokazali, da je uspešnost priporočilnega sistema z eksplicitnimi značilkami značilno boljša od implicitnih značilk.

A novel NIR laser-based sensor for measuring the surface moisture in polymers (2015)

BEGUŠ, Samo, BEGEŠ, Gaber, DRNOVŠEK, Janko, HUDOKLIN, Domen.
Sensors and actuators. A, Physical, ISSN 0924-4247, Jan. 2015

Za merjenje površinske vlage in vlage ob površini kompleksnih elementov s tankimi stenami, smo razvili in testirali brezkontaktni senzor površinske vlage.
In order to be able to measure the surface and near-surface moisture on a complex geometry with thin walls, a novel, non-contact, light-reflection type of moisture sensor was designed and investigated.

Heat loss (2015)

V. Batagelj, V. Žužek, J. Drnovšek, J. Bojkovski.
International Journal of Heat and Mass Transfer, Volume 85, June 2015

Heat loss is one of the key parameters that cause temperature errors during the calibration of thermometers in metal-freezing-point cells and thus increases the measurement uncertainty. At temperatures above the freezing point of tin, thermal radiation becomes the dominant mode of heat transfer. In addition, radiative heat transfer is especially important in the cells’ glass structures, where total internal reflection (known as “light piping”) can occur. A quantitative measure of the radiative heat loss is difficult to determine with measurements, but a qualitative check can be performed by measuring the vertical temperature profile in a cell during a freezing-point realization. Our custom-built model is capable of modeling both the radiative and conductive heat transfers and can deal with complex radiation phenomena specific to the particular case study. The modeling and experimental results are used to give an estimation of the error due to heat losses.

Multi-channel atomic magnetometer for magnetoencephalography: a configuration study (2014)

KIM, Kiwoong, BEGUŠ, Samo, XIA, Hui, LEE, Seung-Kyun, JAZBINŠEK, Vojko, TRONTELJ, Zvonko, ROMALIS, Michael V.
NeuroImage, ISSN 1053-8119, 1 Apr. 2014, vol. 89, str. 143-151, ilustr., doi: 10.1016/j.neuroimage.2013.10.040.

Magnetometri z optičnim črpanjem predstavljajo alternativo SQUID magnetometrom, tudi na področju detekcije bioloških magnetnih signalov. Njihova dobra lastnost je njihova zmožnost delovanja kot večkanalni senzor, čeprav je večina sestavnih delov skupna vsem kanalom. V članku sta predstavljeni dve konfiguraciji večkanalnega magnetometra. Opisane so meritve in lokalizacija magnetnih signalov slušnega korteksa.