Jo Sep 5, 2021
Jang Kyong Wol, researcher of Robotics Institute presented a paper “A Tool Tilt Angle Calculation Method in 5-axis Flat-end Milling for Free Surface Machining” to EI Journal “International Journal of Industrial and Manufacturing Systems Engineering”.
Having analyzed the previous research results, she pointed out that CAD/CAM systems were not fully functioned in free surface machining because of the complex expressions.
Using quadric equation she succeeded in simply calculating the tool tilt angle and machining strip width produced in free surface machining with 5-axis flat-end milling. From this she proposed a calculation method to shorten the machining time by a great deal as well as to improve the effectiveness of machining.
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Jo Sep 2, 2021
Jon Min Hyok, lecturer of Faculty of Shipbuilding and Ocean Engineering presented a paper “Determination of a safety criterion via risk assessment of marine accidents based on a Markov model with five states and MCMC simulation and on three risk factors” to SCI Journal “Ocean Engineering”.
He pointed out the shortcomings of the previous research that failed to give a scientific analysis of accident risks according to their types in the correlation, and he analyzed the data of the accidents occurred in the past. On the basis of this, he proposed for the first time Markov model that has major types of marine accidents as state space and numerically assessed marine accident risks with Markov Chain Monte Carlo Method.
He also assessed the marine accident risks considering the state of the seas, traffic density and the length of the ships.
Combining these assessment methods he set the criterion of marine safety in a particular sea area.
His proposals that do not need a large scale of data collection are simple and can be applied to any marine accidents.
These methods and criterion would make it possible to ensure safe navigation by warning risks in advance on the waterways and to minimize the loss of human and material and environmental damage by dint of an immediate action in case an accident happens by laying marine rescue equipment on the waterways and sea areas with high chances of potential risks.
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Jo Sep 1, 2021
Jong Kwang Hyok, the head of Laboratory at Faculty of Applied Chemical Engineering and his research group succeeded in producing non-toxic low-cost nano micellar functional material that can be used as starch derivative for drug delivery, high purity refiner of the object material and environmental improvement material with our own raw material.
This functional polymer based on starch guarantees 15~80℃ of thermal response range, ±0.1℃ of response accuracy, 1~10.4 of pH response range, and 50~90mg/L of micelle critical concentration range.
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Jo Aug 18, 2021
Kim Jin Hyok, student at Faculty of Physics presented a paper “Joint Estimation of Self-mixing Interferometry Parameters and Displacement Reconstruction Based on Local Normalization” to SCI Journal “Applied Optics”.
During the research he found out that normalization methods used in processing self-mixing signals proved to be irrational in practical application because of the limitation in coverage and measurement accuracy due to the changes in some information of signals.
Therefore, he proposed a local normalization that enables high-speed accurate measurement of major constants of sensors by reducing the number of sample points, and a simple algorithm with which displacement information of the object can be accurately determined on the basis of it.
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Jo Aug 16, 2021
Researcher Hong Myong Son at Faculty of Materials Science and Technology and his research group succeeded in producing non-magnetic hard alloy which contains no cobalt with domestically available raw materials. This kind of alloy is used as the basic material of molding tools and is urgently needed in the various sectors of the national economy.
The hardness of this alloy is more than HRA 91, the bending strength more than 1.8GPa and the saturation magnetization strength less than 3Gs.
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Jo Aug 9, 2021
Pak Se Yang, a researcher at Science Engineering Institute, reported a paper “Data-driven Robust Controller Design by Geometric Constraints in Frequency-Domain” in SCI magazine "International Journal of Dynamics and Control".
In the paper, he found that the representation of the performance factor of the Robust controller with geometric limit in frequency domain has a drawback of disagreement between the control ability and design characteristics due to the strict assumption and large error, and proposed a new method to enhance the control ability by improving geometric limit.
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