Jo Feb 17, 2022
Ri Sok Chol, a section head at the Faculty of Metal Engineering employed genetic programming (GP) to derive a CaO-SiO2-Al2O3 slag viscosity equation and presented an algorithm for it.
Slag viscosity is a key property that determines the stability and productivity in the metallurgical furnace operation, and it is of great importance in understanding the fluid dynamic of molten slags and slag-metal reaction kinetics during the pyrometallurgy process.
Up to now, there have been many experiments to measure, and models to estimate slag viscosity. Viscosity models can be classified into explicit models, structural models, and miscellaneous models according to the way in which they are connected to the description of slag structure.
A slag viscosity equation described with only slag composition and temperature was successfully derived by genetic programming (GP).
The viscosities of CaO-SiO2-Al2O3 system slag can be simply and expediently calculated in a wide range of compositions and temperatures by using the derived viscosity equation.
The average relative error between the values obtained by the equation and the experimental data used for its derivation is as low as 17.1%. To evaluate the accuracy of the viscosity equation of CaO-SiO2-Al2O3 system slag, experimental data and results calculated by many researchers and not used for the derivation of the viscosity equation were compared, and a reasonably good agreement was demonstrated between the results calculated by viscosity equation and other researchers’ experimental and calculated data. The calculation of viscosity showed higher accuracy than previous models.
His essay “Derivation of CaO-SiO2-Al2O3 System Slag Viscosity Equation by GP” was carried in SCI Journal “Journal of Mining and Metallurgy, Section B: Metallurgy”.
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Jo Feb 14, 2022
Kang Po (late 13th century – early 14th century) was a famous astronomer and a mathematician in Koryo.
He found a solution to a biquadratic equation which was not found until the 19th century in Europe. Thus, he made the most advanced and correct calendar in the world of those days “Susiryok” (a primitive calendar) and even a numeration table for easy correction of them.
Those days when farming held an overwhelming proportion in the economy, it was of vital importance to make a calendar that showed correct subdivisions of the seasons.
At that time people used a lunar calendar where there were 354.370 5 days in a year, so after 33 years there was a gap of about 1 year between solar and lunar calendars. Therefore, it was impossible to figure out which season a particular month belonged to.
In order to overcome this shortcoming, lunar calendars had to undergo a huge mathematical calculation for the correction of seasons
Nevertheless, limited mathematical knowledge of those times made it difficult to upgrade calendars every year.
Kang Po, who passed the state examination in 1294, volunteered to shoulder the heavy burden of making a calendar.
He made a correct calculation of the orbit of the sun according to the 24 divisions of the year, on the basis of which he succeeded in making a new correct calendar called “Susiryok”
Not satisfied with this, he decided to find a system of calculation for easy and constant correction of existing calendars.
With painstaking studies and efforts, he discovered his own original formula which is now known as x4+ax2+bx+c=0, and formed a numeration table “Susiryokripsong” necessary for calendar correction.
People in the neighbouring countries expressed their admiration and envy, saying that this was the very world-shaking miracle and that Koryo was a great power of culture.
The Yuan Dynasty not only introduced his new Susiryok as it was but also published his numeration table in the book “Taedongthonggwe”.
Having devoted all his life to improving a calendar, he wrote a book “Susiryokchopbopripsong”, where he made known the secrets of his calendar in 1343.
This is the oldest one of all the astronomy books known to the world so far.
It was not until the 19th century that Hono, a British mathematician, obtained a biquadratic equation. Kang Po was indeed a world-famous astronomer and a great mathematician.
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Jo Feb 13, 2022
Jang Jong Hyok, a researcher at Faculty of Applied Mathematics, has developed a teaching aid program for numerical analysis suitable for students’ psychological characteristics and engineering applications. Students are using this program to deepen their knowledge of numerical analysis.
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Jo Feb 10, 2022
Sin Sa Im Dang is a famous female painter and the mother of a great scholar Ri Ryul Gok.
Sin is her last name and Sa Im Dang is her pen name. She was born into a ryangban (aristocratic) family in Kangrung, Kangwon Province.
Her father, Sin Myong Hwa, despite his excellence in learning and virtue, kept himself from the service in the government.
Instead he remained jinsa (a person who has passed the primary state examination only) all his life devoting himself to the education of the rising generation. Her mother Mrs. Ri was simple and honest, yet strict and generous in the education of her children.
Sin Myong Hwa had no sons but five daughters, the second of whom was Sa Im Dang.
Having started studying when she was a very small child, she was good at everything like composition, penmanship, painting, embroidery, etc.
Especially, she was brilliant at painting. At the age of 7, she caught people’s admiration by painting a landscape and grapes with An Kyon, a famous painter in the 15th century as her model.
This was such a progressive style of painting as a number of contemporary artists were immersed in painting exotic scenery and 4 noble characters (Japanese apricot blossom, orchid, chrysanthemum, bamboo)
Her masterpieces still found include “Eggplant”, “Grapes”, “Mallard”, “Mandarin Fish”, “Heron in a Pond”, etc.
Her paintings were so lifelike that when she put out a painting in the yard, cocks and hens flocked together to peck at the insects in it. When a woman was worried about her borrowed skirt soiled in a wedding, Sa Im Dang painted a delicious-looking bunch of grapes on it. These stories show the distinct creative personality of a fine warm-hearted woman artist who loves her life and is rich in national emotion.
Her patriotism and profound humanity were also reflected in her poems and education of her children. At the age of 19, she got married to Ri Won Su, who was working as a kamchal, a position pretty low in official rank. Soon afterwards, her father died and she moved to Hansong for a married life with her widowed mother left alone. She never forgot her native village and her mother.
One day she was pleased to visit her mother after a long time. After some days of pleasure and happiness, she had to part from her mother. With tears in her eyes, she composed a poem on Taegwan Pass (a big pass across the road from Kangrung to Hansong) looking over her native village and yearning for her mother
As a fine mother, she paid a great deal of attention to the education of her children.
She had 4 sons, all of whom she exercised strict control over with fixed quantities of study every day so as to bring them up to be talents serving their country.
Her children, under the influence of their mother, studied hard to become famous. Among them, her third son Ri I (pen name – Ryul Kok) was distinguished.
From the age of 3, he learnt to read and at the age of 8 he composed a poem, thus startling people. Having passed the primary state examination at the age of 13, he consecutively served in various government posts for over 30 years. During this period he proposed a number of patriotic measures for developing the country and strengthening the national defense. Besides this, his fame as a great scholar reached far-away Ming and Japan. Her youngest son, Ri U, who inherited delicate penmanship from his mother, was also a noted calligrapher.
Sin Sa Im Dang, a famous woman artist and a mother who brought up their children to be able talents, passed away at the age of 48.
Although she failed to produce works of art based on reality, which showed her social and class limitations, she managed to paint beautiful lifelike coloured pictures contrary to the subjective black and white drawings that reflected the hobbies of feudal rulers of that time.
This served as a notable contribution to the development of realistic Korean painting.
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Jo Feb 7, 2022
Josonjol (Korean bow) is admirable greeting etiquette whereby people can fully express mutual respect and politeness with sincerity. It is one of the good manners and customs of our people, who have had observed noble and elegant proprieties from olden times.
Chairman
The term jol (bow), which means “bend one’s back” or “lean forward”, is a pure native word of our country that is indicative of greeting etiquette peculiar to our nation.
Josonjol, the traditional greeting of the Korean nation, is divided into sonjol (a bow in standing position) and anjunjol (a bow in kneeling position).
Sonjol, which is made outdoors, is subdivided into deep, common, and half bows according to greeting partners and the degree of bending.
For a deep bow you bend your body down by almost 90 degrees in standing position, for a common bow you bend your back by about 45 degrees, and for a half bow you just bow your head slightly.
Deep bows were made to the people to whom you had to pay your greatest respect such as the elderly and older ones higher in the degree of kin relationship, common bows were exchanged between people of the same age or those including relatives by marriage who had to treat each other with due courtesy although they were not very old, and half bows were made by older people in return for the bows by younger ones.
There were no differences in the way of making sonjol for men and women, and the deeper you bent your upper body, the more courteous it was regarded as. On the contrary, if it lasted too long for courtesy, it might be considered rude as it looked like a silent tribute for the dead.
When they met on the street, Korean people used to either bend their upper bodies or bow their heads in accord with their greeting partners to show respect before they exchanged words of greeting, which shows noble praiseworthy greeting manners of their style they have observed.
Anjunjol is also subdivided into deep, common and half bows according to greeting partners and the degree of bowing heads. It is for indoors and it differs from sonjol for men and women.
As deep bows were regarded as the most courteous one, they were usually made on ceremonial occasions and to people of high social status for the greatest courtesy.
Common bows were usual in everyday life and usually made on the New Year’s Day or to the elders, the relatives in the same degree of kin relationship and the people they first met. In the case of men, however, deep bows were made on the New Year’s Day while common bows, not deep ones, were often made on their wedding days or 60th birthdays. Similarly, deep bows as well as common bows were common for children on the New Year’s Day. That is why a common bow was regarded as similar to a deep bow in terms of courtesy in the past.
Half bows were made by seniors in acknowledgement of juniors’ bows, and also between people on intimate terms. They simply bowed their heads slightly in kneeling positions .
As mentioned above, you could see that although there are many greeting manners in the world, none of them is clearer than josonjol, which is varied in different places and on different occasions.
How our country could be widely known to the world as a country of courteous people in the East is also attributable, to some extent, to the fact that Korean people had created and constantly developed such admirable greeting etiquette.
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