Brilliant LeaderShip

Teaching in Detail

One spring day Chairman Kim Jong Il visited the park of Mangyongdae Schoolchildren’s Palace (then) for memorial tree-planting. Lest the Chairman, who was always busy with the state affairs, should waste much time ...

Historic Significance Elucidated by the Chairman

Chairman Kim Jong Il was conducting the revolutionary activities at Kim Il Sung University when one day in February, Juche 51 (1962), he shared with his fellow students comments on the Chongsan-ri ...

Autograph Order Delivered to “Young Bridegroom”

In the liberated fatherland, there was a young man who had the honor of serving the army near President Kim Il Sung. One day in November, Juche 38(1949), when he rushed to the ...

Braving the Rough Seas

One day in March, Juche 101(2012), the respected Comrade Kim Jong Un made a visit through the wild waves to Cho Island. Being greeted by the commanding officers, he shook hands with them ...

Greatest Pleasure

In January, Juche 104 (2015), the respected Comrade Kim Jong Un visited the newly built Pyongyang Mushroom Farm (then). Enjoying the panoramic view of the farm, he said with affection that a glance ...

What is Pleasing

It happened when the respected Comrade Kim Jong Un was inspecting a building-materials production base. One of the leading officials of the factory courteously expressed his determination to not only produce more building ...

News

Jo Feb 20, 2024

Quality index of cast aluminum alloy is a measure to evaluate its quality based on tensile mechanical properties such as yield strength (YS), ultimate tensile strength (UTS), elongation to fracture (Ef) and strain energy density W.

Quality index Q0 evaluates material quality on the basis of the balance between YS and W, and it evaluates material’s potential in combination of tensile strength, ductility and toughness.

Its calculation formula involves strain energy density W as a term and W is calculated by integration of true stress–true strain tensile flow curve. So Q0 can be evaluated only if the tensile flow curve of the alloy is known and it may make the use of Q0 difficult.

Yang Won Chol, a researcher at the Faculty of Materials Science and Technology, has developed an approximate formula for calculating Q0 according to YS, UTS and Ef without requiring W.

He developed approximate formulas for Q0 which are expressed as a function of YS, UTS and Ef using multiple linear and quadratic regression models, and evaluated their performances from the viewpoints of mean absolute error (MAE), mean relative error (MRE), determination coefficient (R2) and simplicity. The results demonstrated that they have excellent performances.

The MAE, MRE, R2 and F-statistic of the multiple linear regression model for Q0 are respectively 19.981 MPa, 3.792%, 0.944 and 523.344, and the MAE, MRE, R2 and F-statistic of the multiple quadratic regression model for Q0 are respectively 3.322MPa, 0.566%, 0.998 and 7 277.034.

These approximate formulas could be widely used to evaluate the quality of cast aluminum alloys for materials designers and engineers in practice.

You can find more information in his paper “Approximate formulas for quality index Q0 of cast aluminum alloys according to mechanical tensile properties using multiple linear and quadratic regression models” in “ International Journal on Interactive Design and Manufacturing” (EI).

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Jo Feb 18, 2024

One of the folk festivals our people have celebrated from olden times is Jongwoldaeborum (lunar January 15). Jongwoldaeborum was also called Sangwon. The festival usually started on January 14. The 14th was called ‘small full moon day’ and the 15th ‘big full moon day’. On the day our people held some interesting ceremonies reflecting a simple wish for good luck and rich crops in the new year.

On the evening of the day everybody climbed the hills at the back of their villages to enjoy the full moon, which was called welcoming the first full moon.

The custom of welcoming the first full moon enjoyed by everyone implies the following.

It was said that if a single man saw the moon first, he would marry a girl with a fair complexion and if a sonless man took the first, he could have a fine son. That is why people tended to offer the best places at the front to single and sonless men so that they could be the first to see the moon, and when a single got married to a pretty girl or when somebody got a baby son that year, people said it was attributable to their watching the first full moon. Some people wished themselves good luck watching the rising round moon and made bows several times. Some others predicted the success or failure of that year’s farming from the shape, color and position of the full moon.

Popular and exciting folk games for the festival were erecting a stack of grain stalks on the small full moon day and welcoming the first full moon, torch fighting, marrying a fruit tree off, tug of war, wagon fighting, kite-flying, pinwheel whirling, etc. on the big full moon day.

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Jo Feb 16, 2024

When the dimension of data is larger than the number of samples, linear discriminant analysis (LDA) cannot be applied directly to high-dimensional data. This case is called small-sample-size (SSS) or under sampled problem.

To solve this problem, some local learning based various image clustering models are proposed.

Pak Kwang Jun, a lecturer at the Faculty of Applied Mathematics, has proposed a local learning based exponential regularized discriminant clustering model.

In the proposed local exponential regularized discriminant clustering (LERDC) model, local scatter matrices of regularized discriminant model are projected in the exponential domain in order to handle the SSS problem of LDA. In the proposed LERDC model, for each image, the local image matrix is constructed comprising k nearest neighbor images, and the local exponential regularized discriminant model (LERDM) is devised to evaluate the clustering results for the images in the local image matrix.

To verify his method, he compared it with existing state-of-the-art local learning based clustering approaches. The results showed that the proposed LERDC model achieved a comparable clustering performance to that of the near competitor LDMGI model which is based on LDA.

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Students on “Risang” Local Network (1)

“Risang”, homepage for distance education of Kim Chaek University of Technology, has been making the part-time learners realize their ideal to the full.

Nov 11, 2022