Jo Sep 15, 2026
Magnetic compass based on MEMS is a device that can display the course of ships and the heading of aircraft, and it is widely used because of its fast measurement and low cost.
Due to the characteristics of Earth’s magnetic field and the environmental effects on magnetic compasses, determination of heading based on Earth’s magnetic field measurement still exposes several problems to overcome. Thus, lots of efforts have been made to improve the accuracy of digital magnetic compasses in different external conditions, which resulted in the development of many calibration methods.
Preceding research papers described that the locus from the sensing axes of magnetic compass is an ellipse or ellipsoid due to the influence of magnetic interference on the magnetic compass.
Ri Yong Rim, a researcher at the Faculty of Naval Architecture and Ocean Engineering, proposed a method for compensating the accidental error and improving the accuracy of MEMS magnetic compass by using robust ellipse fitting.
In order to evaluate the effectiveness of the objective function, he performed ellipse approximations by the measured values under artificial random noise. As a result, he identified the trend and shortcomings of the new objective function, and further improved the objective function to overcome the shortcomings.
Then, he obtained compensation coefficients and compensation errors by the algebraic ellipse approximation and by the improved ellipse approximation, calculated the heading, and compared it with the actual heading. The result demonstrated that the improved ellipse approximation model had good noise suppression performance and adaptability.
You can find more information in his paper “Research on Improving Heading Accuracy of MEMS Magnetic Compass Based on Robust Ellipse and Spheroid Fitting” in “Proceedings of KUTIC-2025”.
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Jo Sep 14, 2026
Today, models of cooperative games with transferable utility (TU-games for short) have been widely used in many fields including economics. One of the most important problems in cooperative TU-games is to determine rational imputation, and computing such imputation within a limited time is of practical importance. So far, cooperative TU-games have used the Shapley value and the nucleolus to determine imputation, but the problem of computing the nucleolus of classical TU-games is NP-hard. In addition, the Shapley value computation in classical cooperative TU-games requires exponential time.
GWO (Grey Wolf Optimizer) is an algorithm to solve optimization problems by simulating the foraging process of grey wolves.
O Un Suk, a lecturer at the Faculty of Applied Mathematics, proposed an algorithm for computing rational imputation (an element of the core) in TU-games with nonempty core within a limited time.
The calculation experimental results demonstrated that the proposed algorithm is much better than the calculation of the Shapley value if the number of players exceeds four in classical TU-games.
If more details are needed, please refer to her paper “Algorithm for Computing the Rational Imputation using Grey Wolf Optimizer in Cooperative TU-Games” in “Proceedings of KUTIC-2025”.
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Jo Sep 13, 2026
The magnetometer is one of the most suitable attitude sensors for almost all low earth orbit (LEO) satellites.
There have been lots of efforts to develop attitude estimation algorithms using only a magnetometer and a spacecraft attitude estimation algorithm utilizing only magnetometer readings was developed. Although the algorithm can provide high accuracy of satellite attitude estimation, it is widely known that the unscented Kalman filter (UKF) faces heavy computational load.
Kim Hak Min, a researcher at the Faculty of Aerospace Engineering, proposed an attitude and angular rate estimation algorithm based on quaternion estimation (QUEST) and unscented Kalman filter (UKF).
The proposed algorithm uses only three-axis magnetometer as an attitude sensor and works in two stages. In the first stage, the QUEST uses magnetometer measurement vector and its derivative to estimate a coarse attitude. In the second stage, these estimated values are used as quaternion measurement data for UKF processing. The state vector for UKF consists of attitude parameters and angular rate vector. As a result, it is possible to estimate satellite attitude and get angular rate with high accuracy and small computation load.
The simulation result showed that the attitude of a satellite can be estimated with higher accuracy than 0.2° with small computational load.
You can find the details in his paper “Research on LEO Satellite Attitude Estimation Based on Quaternion and Unscented Kalman Filter” in “Proceedings of KUTIC-2025”.
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Jo Sep 11, 2026
OpenMP and MPI were preferred for parallel programming in the modes of shared memory and distributed memory, but now research has been focused on hybrid programming using both MPI and OpenMP and Apache Spark programming, which targets fast big data analysis.
Commonly, however, configuring a cluster environment requires more time than programming, and moreover, the difference between MPI-OpenMP of a parallel system using C language and Apache Spark of a distributed system using Java is one of the challenges to anyone who are not familiar with configuring Linux cluster as well as deploying Apache Hadoop stack.
Kim Ryo Chol, a section head at the Faculty of Information Science and Technology, proposed an integrated platform in which MPI-OpenMP and Spark parallel programming are both possible.
Virtual machines needed for parallel computation are provided by the private cloud based on OpenStack IaaS.
Applying the proposed method, he built an integrated platform for parallel programming, thus reducing the time for cluster environment configuration.
For more information, please refer to his paper “An Integrated Platform Architecture for MPI-OpenMP and Spark Parallel Programming on Cloud Environment” in “Proceedings of KUTIC-2025”.
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Jo Sep 10, 2026
The use of ozone gas started about a century ago and it has been used to purify water polluted by microorganisms. The chemistry of ozone in aqueous solutions is complex, and the direct reaction with molecular ozone and the indirect reaction with radicals generated when ozone is dissolved in water are considered for the process of water treatment with ozone. The direct and indirect reaction pathways of ozone generate different oxidation products and they are controlled by different kinetics.
Direct reaction of ozone has been quite well understood by previous researchers. The studies of ozone reactions and decomposition are still active, and most researchers are working on kinetics. The exact analysis of ozone reactions is still difficult due to very complex ozone reactions and insufficient information on reaction kinetic constants.
In theoretical studies of the UV-induced destruction of ozone layers in the earth's atmosphere, some researchers performed calculations of the stability of ozone-water vapor complex. The previous studies dealt with the reaction between molecular ozone and water vapor, but no first-principles studies have been carried out on the case of ozone gas dissolved in water. Therefore, first-principles study of ozone decomposition in water is necessary to improve the efficiency of water treatment by ozone.
Choe Un Hwa, a researcher at the Faculty of Physics, has determined reaction pathways for enhancing the efficiency of ozonation through first-principles considerations of ozone decomposition in water.
She newly defined the transition state that might be found during ozone decomposition in water and carried out a quantitative chemical calculation of ozone decomposition reactions in water by using the density functional method (DFT/6-31G*).
The results showed that the relative probability of the reaction to obtain H2O2 + O2 among the four possible reactions between O3 and H2O in gas and water is high, which indicates that the improved oxidation of ozone can be used to improve ozonation efficiency.
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Jo Sep 9, 2026
Water is indispensable for human life and economic development, and therefore, water treatment is one of the primary technical processes essential for people’s living and the overall sectors of the national economy.
Desalination by electrosorption is a novel water treatment technique, which is a combination of electrochemical method and adsorption method of separation. It is employed to purify water by removing salts and other substances dissolved in water by using the adsorption of ions and charged particles in water when an electric field is applied to an electrode made of conductive adsorbent material.
The core of electrosorption technology is the selection of electrode material and the design of electrode structure. Carbon adsorbent materials such as activated carbon, activated carbon fibers, graphene, carbon nanotubes and carbon aerogels are used as electrode material.
Kim Chang Sok, a researcher at the School of Science and Engineering, calculated the desalination rate by electrosorption of activated carbon electrodes from the electrical double layer phenomena at the liquid interface and the characteristics of activated carbon, and investigated the main factors i.e. voltage, interelectrode distance, water flow rate and treatment time, influencing the desalination of groundwater by electrosorption using electrodes. On this basis, he determined the optimum electrosorption conditions.
When the voltage was 2V, the interelectrode distance 15mm, the water flow rate 4m3/(kg·h) and the time 45min, the electrical conductivity and the hardness decreased by 43.8% and 33.5%, respectively.
The results confirmed that water treatment by electrosorption is an effective method with high desalination and softening efficiency, low power consumption and no environmental pollution.
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