Jo Jan 29, 2022
These days study on a learning method for getting a dynamic characteristic model without the knowledge of an object in the field of a hierarchical supervisory control system has been actively being conducted. However, no method of applying it to existing production processes by speeding up Q-learning convergence has been proposed yet.
Kim Song Ho, a section head at Faculty of Automation Engineering, proposed a two-layer intelligent supervisory control system to adjust the online optimum setting point of the control system and set forth a new method to improve Q-learning convergence.
Unlike previous methods, the core of his suggestion is that it helps overcome trial and error Q-learning process, the weakest point of this learning, and achieve the fastest Q-learning convergence by setting optimally the way of automatically extracting experience rules of process operation from historical operation data and the initial phase of Q-learning.
His suggestion is estimated to have great practical significance in making large-scale continuous industrial processes unmanned and intelligent as it is supposed to minimize the effect of environmental changes and to guarantee product quality and stability of process operation.
He presented his essay titled “On-line set-point optimization for Intelligent Supervisory Control and Improvement of Q-learning Convergence” to SCI journals “Control Engineering Practice”.
...
Jo Jan 26, 2022
PCPs have been widely used to lift heavy oil and multiphase material in oil fields.
Previous approaches for slippage calculation takes too much time and they cannot be used for real-time control of PCPs. Furthermore, they cannot be adopted to liquid with low viscosity like water.
Om Il Ryong, an institute head at Faculty of Mining Engineering, and his research group have found a way to analytically calculate the hydrodynamic characters of one-lobe PCPs without using Navier Stokes equations and CFD.
First they determined the length of gaps analytically to convert axial and transversal gaps into space between parallel plates, hydrodynamic equivalence.
Then after they made some assumptions considering the structural periodicity of a PCP, they made an analytical determination of the overall hydrodynamic resistance and obtained flow rate change according to pressure differences.
Thus, they laid the foundation to rapidly calculate the slippage inside a PCP and realize the automatic control of PCP systems. Therefore, they could reduce the calculation time of 8 days in the past to less than 1 second.
He presented his essay titled “A New Analytical Approach to Calculate a Slippage inside a Progressing Cavity Pump with a Metallic Stator by Using a Middle Streamline and a Structural Periodicity” to SCI journals “SPE JOURNAL” .
...
Jo Jan 24, 2022
Kong Myong Il, a researcher at Semi-conductor Institute, and his research group have developed PTC (positive temperature coefficient) resistance material necessary for constant operation of facilities under the condition of room temperature even in low-temperature zones, and they have been expanding their achievements.
This material provides room temperature resistance of 20Ω, Curie temperature of 30℃ and temperature coefficient of resistance of over 18%/℃.
...
Jo Jan 21, 2022
Finding optimal routes for main haul roads development not only enables us to reduce construction work load so as to shorten the period of opening up surface mines and start excavation as early as possible but also provides good conditions for optimal transport.
So far researchers have used genetic and DIJKSTRA algorithms, A* algorithms and ant colony algorithms, all of which are suitable only for plain surface mines.
Hong Kun Ui, dean of Faculty of Mining Engineering, grasped the shortcomings of previous research while working to find routes for main haul roads in the mountainous areas with complex relief and gave a scientific proof to its limitation.
First, a 3D model terrain was made by using Surpac software and input data for finding optimal routes were prepared by processing string file of Surpac software and extracting the 3D coordinate values in the mine area.
Then he developed a new search algorithm with principles arising in the haul road layout as constraints.
This proposal, which ensures broad-range search with continuous addition of search points regardless of topographic conditions, was adopted in a surface mine. It helped reduce enormous work load of 138 000m3.
You can find more information about this in his paper titled “Mountainous Surface Mines using A* algorithm” presented to SCI journal “Archives of Mining Science”.
...
Jo Jan 20, 2022
Kang Hwi Song, a researcher at Faculty of Electronic Engineering, and his research group have succeeded in manufacturing an Optical Passingtime Detector using infrared optical technology and Zigbee wireless communication and are expanding their achievements. This detector ensures speed measurement accuracy of 0.01s in a 30-meter section which is an important item in selecting and training reserve footballers.
As it is portable, it can be taken for camping drill and also be used in outdoor conditions with high illuminance as well as indoors. Moreover, it offers high stability and accuracy of speed measurement. The range of time measurement is 0~100s and the measurement accuracy is 0.01s.
...
Jo Jan 18, 2022
Pak Thae Un, a section head at Faculty of Mining Engineering, studied and introduced a simultaneous blasting method by a high-voltage blaster whereby they could improve rock cutting property by enhancing the effects of simultaneous blasting in blasting operations.
They applied voltage of over 150v to each electric igniter linked to tens of detonators connected in series in the blasting circuit network with a high-voltage blaster generating high voltage impulse in order to cause discharge explosion effect, thus reducing the average detonation time to 4.7±1ms.
It resulted in the improvement in the effects of simultaneous blasting of blasting hole charges, which meant far more improvement in rock cutting property.
...
© 2021 Kim Chaek University of Technology