Jo Mar 3, 2022
Hunminjongum, invented in the 15th century, is the national alphabet of our own.
As it is literally interpreted into “correct sound for teaching common people”, it means “a fine alphabet to write the correct sound for teaching common people”.
Our people had used Ridu characters (Chinese characters used for their sound values to write Korean particles, endings and auxiliary verbs in order to facilitate the reading of Chinese texts) since the period of the Three Kingdoms, when Hunminjongum, the most advanced alphabet, was invented in 1444.
In those days King Sejong commissioned several scholars at Jiphyonjon (supreme research institute in the feudal Joson dynasty) like Jong Rin Ji, Sin Suk Ju, Song Sam Mun, Choe Hang, Pak Phaeng Nyon, etc. to do research into making characters.
They succeeded in making our own characters in January, 1444 (December, 1443 by the lunar calendar) and made it public to the world as Hunminjongum.
When it was invented, it consisted of 28 letters, with 17 initial sounds and 11 medium sounds.
It has several superior properties.
It makes it possible to give a vivid expression of our feelings at will as well as to express all sorts of sound in letters
Moreover, it is easy to learn and use as it is based on a scientific principle and on a certain system.
The invention of Hunminjongum is of great historical significance since it not only provided possibility to establish the standards of the national language and to ensure the oneness of our linguistic life but also demonstrated the scientific wisdom of the Korean nation, developed the national culture and further enriched the heritage of our language culture.
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Jo Mar 1, 2022
The contests ended on February 14, 2022.
The first contest was held from 4 to 7, February. About 22 300 contestants from tens of countries and regions including our country, China and India took part in it. 210 belonged to category 1, 3 191 to category 2, and 18 902 to category 3. 5 problems were set forth in category 1, none of which were challenge problems.
A total of 38 contestants won the first place in category 1 – 19 from the DPRK, 2 from China, 4 from India, 2 from Vietnam, 1 from Singapore, 1 from Germany, 1 from Portugal, 3 from the UK, 2 from the US, and 3 from Japan.
8 out of the 19 winners of our country are students at Kim Chaek University of Technology.
Our country accounts for the half of the world winners, and our university 21.052%, which rises to 42.105% in our country.
In the meantime, 1 from KUT took the first place in category 3.
The second contest went on from 11 to 14.
About 19 300 contestants from tens of countries and regions including our country, China and India took part. 170 belonged to category 1, 2 433 to category 2 and 16 755 to category 3. 4 problems were presented in category 1, none of which were challenge problems.
A total of 30 contestants in category 1 won the first place – 19 from our country, 2 from China, 5 from India, 1 from Argentina, 1 from the UK, and 2 from Japan.
All of the 8 students from Kim Chaek University of Technology took the first place in category 1.
19 winners from our country constitute 63.3% of the world winners, In the meantime, our university amounts to 26.67% in the world and 42.105% in our country.
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Jo Feb 25, 2022
Ri In Sik, a researcher at the Semi-conductor Institute, made an analysis of reverse voltage distribution of high-voltage diode stack considering the effect of temperature.
First, he presented an equivalent circuit of a high–voltage silicon diode taking into account the effects of temperature and reverse voltage, and obtained an analytical expression for impedance of a diode. Then, he proposed the most generalized equivalent circuit of a high–voltage diode stack consisting of a serial connection of several diodes, and obtained an analytical expression for the reverse voltage applied to each diode. As a result, he offered an easy estimation of the reverse voltage distribution of a high–voltage diode stack by an analytical method, not in an experimental way.
High–voltage diode stacks (HVDS) are now widely used in extracorporeal shock wave lithotriptors, diagnostic X–ray equipment, sound detectors, night glasses, high–voltage magnetic compression modulators, high–voltage pulse generators, dust collectors and electrostatic fly–ash separators at thermal power plants.
The most important characteristic of an HVDS is reverse voltage distribution between chips or diodes. If the non–uniformity of reverse voltage distribution is severe, twice the breakdown voltage of P–N junction or more can be applied to the chips or diodes placed on high–voltage terminal and ground terminal, leading to their destructions. The reverse voltage distribution of an HVDS is mainly affected by the characteristics of chips or diodes, such as the dependence of the temperature and the reverse voltage on the impedance of them. The dependence of impedances of chips or diodes on temperature and reverse voltage strongly affect the reverse voltage distribution of an HVDS. Also, according to an HVDS consisting of stacked chips or a serial connection of individual diodes, the leakage impedances connected to the high–voltage terminal and the ground terminal are varied and they strongly affect the reverse voltage distribution. The stacking of chips and a serial connection of the individual diodes are the technologies that have been widely used to manufacture HVDS.
The reverse current of the diode increases and its barrier resistance decreases with increasing temperature and reverse voltage. In addition, when the reverse voltage of the diode increases, the width of the space–charge layer increases, thus the barrier resistance decreases. Consequently, the impedance of the diode decreases with increasing temperature and reverse voltage. Hence, the equivalent circuit of an HVDS consisting of a serial connection of the individual diodes is needed in order to analyze the reverse voltage distribution of it, considering the effects of the temperature and the reverse voltage of the diodes.
That is why, he proposed and analyzed a new equivalent circuit of an HVDS, including not only the impedance and the uniform voltage impedance of each device, but also the leakage impedance connected to the high–voltage terminal and the ground terminal.
The calculated values of the reverse voltage distribution of a high–voltage diode stack were shown to be in good agreement with the measured values.
His essay “Analysis of Reverse Voltage Distribution of High–Voltage Diode Stack Considering Effect of Temperature” is carried in SCI Journal “Solid-State Electronics”.
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Jo Feb 24, 2022
The research group led by Ma Min Gon, vice dean of the Faculty of Information Science and Technology, has developed a Korean braille character reader which converts raised letters read by an image input device into a character code readable by ordinary people.
When books published in raised type for the blind to read by groping are read by an image input device like a scanner, the raised parts are shown in dim dots.
In order to extract these dim dots more precisely, they proposed and realized several new basic methods: binarization by wavelet difference image, tilt estimation by Hough conversion, dot extraction by dot database and Maharanobis distance for precise extraction without being affected by the scanning direction, charline extraction from dots capable of strongly overcoming noises, substitution of braille code for unicode by bidirection scanning, postprocess based on geometrical position of dots, etc.
Thus, they were able to raise the extraction precision up to 96% and the recognition speed up to 1 second per page.
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Jo Feb 22, 2022
A research group led by Ri Yong Min, a researcher at the Faculty of Materials Science and Technology, has developed a screw rolling mill with individually driven rollers and established a rolling process which can produce bars of more than 20mm in diameter through one pass without a roller change from round steel of 50mm in diameter, consuming less power. They will no longer need an ordinary light section rolling mill in machine factories and repair bases that have a great demand for bars in various diameters.
In this rolling process, round steel of 50mm in diameter is heated to 850~950℃ in a heating furnace and is rolled into bars of 20mm in diameter through one pass in a cantilevered 3-helical rolling mill with individually driven rollers that has a large feed angle and an elongation angle before they are cut into necessary lengths.
Thus, they can produce bars of different diameters from short scrap iron by changing no rolls but adjusting the roll gap, and ensure the metal yield of more than 99% and the roundness of ±0.1.
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Jo Feb 21, 2022
Kim Won Ok, a researcher at the Faculty of Information Science and Technology, has developed a C/C++ programming evaluation system to raise practical programming skills of students who are learning C/C++ programming including those who are receiving distance education, and to make an accurate evaluation of the programming assignments performed by them.
What she has done includes the combination of web and other applications by TCP socket communication, the implementation of a C/C++ programming environment by C++ compiler and I/O stream pipeline, accurate evaluation of assignment performance, and the security of learning-related data including assignments by user certification, copy paste protection and encryption.
She herself tried making and running a program so as to make a programming tool and a system for evaluating programming accuracy. This helped raise students’ programming skills and enthusiasm for study, and evaluate their assignment performance rapidly and accurately.
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