For high frequency vibration rejection, constant boundary layer control design and dynamic sliding mode control (DSMC) design using an integrator have been proposed. However, they use only one output feedback, so disturbance rejection and robustness enhancement are limited.

Adaptive SMC (ASMC) is used for control of systems with unknown or bounded disturbances. However, these methods do not keep the sliding variable at the ideal value zero. To increase the robustness of Smith predictor for control of delay processes, a robust Smith predictor and a PI control method for multivariable processes have been developed.

Kim Ho, dean of the Faculty of Automatics, developed a linear PI adaptive dynamic sliding mode control (DSMC) system based on Robust Smith Predictor (RSP).

In order to primarily suppress the disturbance and model perturbation of a plant, he implemented the equivalent control by a PI output feedback control loop. As the outer switching controller is designed for extended systems with an integrator, it automatically becomes a DSMC and chattering free. A linear PI feedback system with sliding variables as output is used for switching gain adaptation of sliding-mode control, and consequently, the optimality and adaptability of PI adaptive algorithm are guaranteed by the linear feedback control theory.

He verified through simulation that the proposed SMC system shows high performance that cannot be achieved by any one control alone for all indexes, namely, tracking performance, disturbance rejection, robustness, adaptability and chattering rejection.

For more information, please refer to his paper “Decentralized PI Adaptive Sliding Mode Controller with Double Output Feedback for TITO Processes” in “Proceedings of KUTIC-2025”.

The age of relics is determined by the amount of natural radiation that they were exposed to in the soil. Among the relics unearthed in our country are many ceramics showing the excellent culture of the nation. Quartz, the main component of ceramics, is compatible with thermoluminescence measurements because of the peculiarity of ceramics manufacture, and the relationship between the thermoluminescence intensity and the irradiated dose can be used to calculate the annual dose and to estimate the age of ceramics. The accuracy of the age is determined by the accuracy of thermoluminescence intensity measurements at the time of heating a quartz sample at a constant rate, and by the accuracy of annual dose estimates.

Kim Sung Ryol, a researcher at the Institute of Analysis, proposed a heating rate stabilization method for reproducibility and accuracy of thermoluminescence intensity and a method for estimating the annual dose rate from a ceramic sample in the soil by MCNP.

Unlike before, he applied heating temperature control to the set-point tracking method to ensure stability and to achieve correct detection of the peaks obtained from the thermoluminescence curve. In addition, he developed an MCNP-based annual dose rate assessment program to ensure the speediness of dating.

It was verified that the internal and external dose simulation calculation functions of the newly-developed computational system are in good agreement with the measurements reported in the literature and that it can be used to determine the annual dose rate of a real object.

The working principle of electron microscopes is to form an image by using electron beams and electron lenses instead of light beams and optical lenses in optical microscopes. The design and focusing characteristics of magnetic lenses determine the main parameters of electron microscopes. The electro-optical (EO) system of transmission electron microscopy can be classified into illumination and imaging systems. The former consists of an electron gun and a focusing lens while the latter is made up of a sample chamber, an objective lens and intermediate and projective lenses. In an EO system, lenses are the most important components and the one that plays a crucial role among lenses is an objective lens.

There are many studies in the literature on the method of calculating the focal length of magnetic lenses in transmission electron microscopes, but these calculations are empirical, based on only pole-piece diameter, gap and the number of excitation turns in a magnetic lens. The effect of the change of various factors such as other structural dimensions, magnetic lens material and magnetic circuit configuration on the focal length is not mentioned, .

In magnetic lenses, the pole-piece diameter and the gap are of primary importance, but the magnetic circuit constituting the lens, the position of the magnetic flux-making coil, and other structural dimensions will influence the magnetic field distribution and the focal length. Therefore, the conventional focal length calculation method presents many problems in the design of real magnetic lenses.

Kim Hak Chol, a researcher at the Faculty of Electronics, proposed a new method of calculating the focal length by simulating the magnetic field distribution and trajectory of a magnetic lens.

Using a simulation tool, he set the structure dimensions, excitation conditions and material settings just like real ones and calculated the magnetic field distribution based on them. Then, he determined the focal length from the trajectory data by means of the method of calculating the focal length based on the electro-optical theory.

Unlike conventional focal length calculations, the proposed method can improve the accuracy of magnetic lens design, with all the factors affecting the focal length in consideration.