Jo Aug 24, 2026
As environmental protection is becoming more and more serious, it is a pressing task to reduce industrial waste as well as to develop eco-friendly material that can be used for people’s living.
Ri Chol Jin, a section head at the Faculty of Earth Science and Technology, has investigated a synthesis method of 13X zeolite using fine granite dust (FGD) resulting from granite processing. Zeolite has good physio-chemical properties as an adsorbent, a cation exchanger, a molecular sieve and a catalyst and it is widely used as a selective scavenger of heavy metals from liquid effluents.
He selected and applied both the alkaline fusion method (770-830℃, 80min) and the hydrothermal process (95-100℃, 8-12h) to the synthesis of 13X zeolite.
What is important in the synthesis of zeolite by using alkaline fusion method is high sintering temperature. He lowered the sintering temperature from 1 300℃ to 800℃ by putting FGD into water and maintaining it for 5 minutes to remove crystalline quartz which has low reactivity.
In addition, it is important to find appropriate sintering temperature at which albite is decomposed more easily than kalifeldspar in FGD because 13X zeolite is chemically concerned with sodium (Na). For this, he calculated the reaction heats of kalifeldspar and albite at the temperature range of 770~830℃.
As a result, he proved that albite has the possibility to be dissolved thermodynamically more easily than kalifeldspar, but the difference between the heat effects of albite and kalifeldspar is not so significant according to the increase in temperature.
Eventually, he successfully synthesized 13X zeolite from FGD with low energy consumption and all other stone processing waste can be recycled by this method.
For more information, you can refer to his paper “Characteristics of flourite{111} surface with various terminations: A first-principles investigation” in “Results in Surfaces and Interfaces” (SCOPUS).
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Jo Aug 23, 2026
It is difficult to find out a suitable type for desired purpose among a large number of mechanisms that can be made by the spatial combination of links and joints. Here, quick calculation of correct mobility is the basic requirement for structural synthesis of parallel robot mechanisms.
Various methods reported in the literature for mobility calculation of closed loop mechanisms fall into two basic categories: an approach for mobility calculation based on setting up kinematic constraint equations and calculating their rank and an approach for finding formulae for quick calculation of mobility without constraint equations. Among them, the former is very useful.
Kim Yong Ho, a researcher at the Faculty of Mechanical Science and Technology, proposed a new method of calculating the mobility of parallel mechanisms by automatically generating velocity constraint equations and calculating the rank.
For automatic generation of kinematic constraint equations, he used formulae which enable automatic generation of the homogeneous transformation matrix and the Jacobian matrix of serial robot mechanisms.
He applied this method to CPM mechanism, Bennett mechanism and Bricard mechanism to validate its correctness, availability and prospectiveness.
For more information, please refer to his paper “Calculation of Correct Mobility of Special Mechanisms Based on Automatic Generation of Jacobian Matrix and Velocity Constraint Equation” in “Proceedings of KUTIC-2025”.
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Jo Aug 21, 2026
Energy harvesting is a prospecting solution for enough energy supply to wireless MSs (Mobile Station) in the communication. MSs use energy to transmit information to an eNodeB or to charge their batteries by received signals.
Unfortunately, MSs do not harvest energy and transmit information at the same time in practice. In order to solve this problem, a researcher proposed a harvest-then-transmit protocol and assumed that terminals employ time division multiple access (TDMA) for information transmission. Although using the harvested energy has many benefits, the dependence of MSs has a negative effect on data rates. Consequently, it is necessary to explore several methods for improving energy-bandwidth efficiency.
In the meanwhile, the most important factors in 5G mobile system are MMF (Maximum Fairness), SR (Sum Rate) Maximum and EE (Energy Efficiency) Maximum. Thanks to these factors, it has good features in contrast to OMA system.
Kim Tong Jin, a researcher at the Faculty of Communication, has investigated a time-allocation and terminal weight method to improve fairness while maximizing data rate in 5G mobile communication systems.
The simulation results show that the proposed scheme is superior in both data throughput and terminal fairness.
For further details, please refer to his paper “Improvement of Maximum Data Throughput and Terminal Fairness using Channel Weights in 5G Mobile System” in “Proceedings of KUTIC-2025”.
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Jo Aug 20, 2026
Power sharing and voltage quality are challenging problems in islanded microgrids with nonlinear loads. Distributed generations (DGs) can be used to improve the power quality in microgrids. However, when several DGs are used for voltage harmonic compensation, the conventional droop control can cause poor harmonic power sharing among the DGs due to mismatched line impedance.
Kim Sung Hyok, a section head at the Faculty of Electrical Engineering, proposed a regulation method of virtual harmonic impedance for proportional harmonic power sharing. This method does not require the prior knowledge of line impedance.
The simulation results showed that the proposed method is effective for proportional sharing of harmonic power by reducing the total harmonic distortion (THD) of voltage at point of common coupling (PCC).
For more information, you can refer to his paper “Distributed Regulation of Virtual Impedance for Voltage Harmonic Compensation in Islanded Microgrids” in “Proceedings of KUTIC-2025”.
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Jo Aug 19, 2026
With the rising demand for satellite communications, the use of low-earth orbit (LEO) satellites is increasing.
MPPT control is more suitable for LEO satellites with relatively short solar cycles and low weight margins. However, there is a tendency to unconditionally use MPPT control regardless of the mission and orbit conditions of LEO satellites, from the existing experiences.
Therefore, it is important to reduce the peak value of battery charging current by reducing the mass of SAR and applying MPPT control according to mission and orbit conditions. It is also necessary to study simple charge control techniques suitable for SAR, including the method of increasing efficiency based on simple switch signal control.
Ho Kum Song, a researcher at the Faculty of Aerospace Engineering, proposed new direct charging control suitable for power systems applicable to lightweight, high-reliability LEO satellites, thus reducing manufacturing cost and increasing efficiency.
The simulation results show that the proposed SAR with direct energy transfer (DET) and constant voltage (CV) control is not significantly affected by environmental conditions and it is more suitable for space environment than conventional SAR.
If more information is needed, please refer to his paper “High-Efficiency Operation of Power Controllers using Solar Plate in Low Earth Orbit Satellites” in “Proceedings of KUTIC-2025”.
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Jo Aug 18, 2026
Local obstacle avoidance is important for mobile robot’s movement.
Several methodologies have been suggested to solve path planning problems. They include mathematical programming, cell decomposition, roadmap approach and potential fields. These techniques prove to be inefficient due to their high computational cost and inaccuracy caused by the trapping in the local minimum.
A vehicle model is a highly nonlinear and time-varying system as far as obstacle avoidance algorithm is concerned. The algorithm must be able to adapt to a variety of changing environments. However, model-based control methods face limitations due to changing environment. Different heuristic techniques such as fuzzy logic systems and cluster optimization algorithms can overcome the weakness of the above algorithm.
Kim Thae Yong, a researcher at the Faculty of Automatics, proposed an obstacle avoidance algorithm based on Deep Q-Learning Network (DQN) that combined reinforcement learning and deep learning.
The inputs of DQN are the coordinates of a mobile robot and obstacles, the moving velocity, and the distance between them. The output is the steering angle of a mobile robot.
The trained DQN model includes both path planning and path tracking techniques and it is computationally fast and applicable to complex environments because the dynamic model of a robot is not used.
Using MATLAB, he built an environment model and a model of mobile robot and performed simulations comparing the proposed algorithm with other obstacle avoidance algorithms in various situations. The simulation results showed that the mobile robot successfully avoided obstacles after 25 000 iterations.
You can find details in his paper “Obstacle Avoidance Control of Autonomous Mobile Robot Based on Deep Q-Learning Network” in “Proceedings of KUTIC-2025”.
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