Two-component (diffuse and quasi-specular) models were developed on the base of incomplete initial data sets (spectral directional-hemispherical reflectances and quasi-specular components measured for several incidence angles). Developed models were applied to the Monte Carlo calculation of spectral effective emissivities and radiance temperature for low-temperature IR on-board blackbody calibration sources.

Developed software was applied to calculation of radiation characteristics of the pyramid cluster calibration target for remote sensing applications.

Three algorithms of Particle Swarm Optimization were applied for global optimization problem in up to 10-dimensional search space and their performances were compared. Common set of benchmark functions was used for performance assessment. Optimal ranges of tuning parameters were determined.

Animation on the right visualizes the optimisation process for a standard 2D benchmark function.

Later, one of these algorithms was used for fitting parameters of the 3C BRDF model to experimental BRDF data.

Feasibility study of combining Beckmann's scattering theory and Monte Carlo ray tracing to computer modeling of reflection from random rough surfaces.

Development of data processing software for cryogenic blackbody calibration in the Far IR spectral range.

Software for computer modeling of transient temperatures in the large-area blackbody radiator with reflecting concentrator.

The blackbody is heating up to the operational temperature of about 1000 K. Average radiator temperature and heat losses through structiral components are shown in the animation as a function of heating time.

The blackbody is heating up to the operational temperature of about 1000 K. Average radiator temperature and heat losses through structiral components are shown in the animation as a function of heating time.

A finite element model was built for the low-temperature cylindrical blackbody with V-grooved bottom. Steady-state temperature distributions were computed using ANSYS

Steady-state temperature distributions were computed for an absolute cryogenic radiometer with electrical substitution. The shell finite element model was created for ANSYS

Two types of electrical heating elements were investigated to evaluate and minimize the substitution non-equivalence of laser radiation optical power by electical power of heater.

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Monte Carlo modeling of the integrating sphere uniform radiation source. The picture for relative distribution of radiance across the exit port of the integrating sphere is adopted from: A.V. Prokhorov and L. M. Hanssen, "Numerical Modeling of an Integrating Sphere Radiation Source," Proc. SPIE **4775**, 106-118 (2002)).

Software for 3D and 2D visualisation of the hemispherical relative distribution of the radiance incident onto the sample center in the integrating sphere reflectometer for Vis and NIR spectral range (the right-hand picture is adopted from: A. V. Prokhorov, S. N. Mekhontsev, and L. M. Hanssen, "Monte Carlo Modeling of an Integrating Sphere Reflectometer," Appl. Opt. **42**, 3832-3842 (2003)).

Ray tracing software for cylindrical mapping of the integrating sphere IR reflectometer and for optimization of mutual positions and orientations of internal baffles (picture is adopted from: L. M. Hanssen, A. V. Prokhorov and V. Khromchenko, "Specular baffle for improved infrared integrating sphere performance," Proc. SPIE **5192**, 101-110 (2003)).

Modification of the Torance-Sparrow model of reflection from random rough surfaces for Monte Carlo ray tracing applications.

Program complex for analytical and Monte Carlo calculations of diffuse view factors in the system of surfaces for geometrical configurations used in radiometric applications.

Program for minimization of temperature non-uniformity for the medium temperature blackbody with three independent heating elements.