• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.161-170
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• 1994

For the preparation of short ceramic fibers of which average length might be in accordance with the opening size of sieve, e.g., 150${\mu}{\textrm}{m}$ or 300${\mu}{\textrm}{m}$, bulk fibers were grounded on sieve screen by applying both compressing and shearing force, and passed through the sieve screen. The grounded fibers were subjected to gravitational settling processes. The classified fibers were observed by scanning electron microscopy and the length of each fiber was measured to correlate the average length with the opening size of the sieve used for grinding bulk fibers. Theoretical analysis show that a free settling technique is ineffective for the classification of fibers by length compared with that of particles. The average lengths of classified fibers estimated by scanning electron microscopy were in good agreement with those obtained by relative packing volume of the fibers. Accordingly, it is confirmed that average fiber lengths can be determined from bulk volume data without photographing, counting and averaging results for hundreds of fibers.

• The Pure and Applied Mathematics
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• v.21 no.1
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• pp.39-50
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• 2014

In this paper, we study screen quasi-conformal irrotational half lightlike submanifolds M of a semi-Riemannian space form $\tilde{M}(c)$ admitting a semi-symmetric non-metric connection, whose structure vector field ${\zeta}$ is tangent to M. The main result is a classification theorem for such Einstein half lightlike submanifolds of a Lorentzian space form admitting a semi-symmetric non-metric connection.

• Communications of the Korean Mathematical Society
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• v.28 no.1
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• pp.163-175
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• 2013

In this paper, we prove a classification theorem for Einstein lightlike hypersurfaces M of a Lorentzian space form ($\bar{M}$(c), $\bar{g}$) with a semi-symmetric metric connection subject such that the second fundamental forms of M and its screen distribution S(TM) are conformally related by some non-zero constant.

• East Asian mathematical journal
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• v.31 no.1
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• pp.33-40
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• 2015

We study the geometry of r-lightlike submanifolds M of a semi-Riemannian manifold $\bar{M}$ with a semi-symmetric non-metric connection subject to the conditions; (a) the screen distribution of M is totally geodesic in M, and (b) at least one among the r-th lightlike second fundamental forms is parallel with respect to the induced connection of M. The main result is a classification theorem for irrotational r-lightlike submanifold of a semi-Riemannian manifold of index r admitting a semi-symmetric non-metric connection.

• Journal of Korea Game Society
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• v.17 no.5
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• pp.133-142
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• 2017

Recently, screen climbing contents such as sports climbing learning program and screen climbing games. Especially, there are many researches on screen climbing games. In this paper, we propose the skeleton correction method based on the body area of a climber to improve the posture recognition accuracy. The correction method consists of the modified skeletal frame normalization with abnormal skeleton joint filtering, the classification of body area into joint parts, and the final skeleton joint correction. The skeletal information obtained by the proposed method can be used to compare the climber's posture and the ideal climbing posture.

• Honam Mathematical Journal
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• v.45 no.4
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• pp.629-647
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• 2023

We introduce the study of a new class of a lightlike submersion d. Then, we derive a relationship between the holomorphic section 𝜙 : K₁ → K' from a screen generic lightlike submanifold of an indefinite Kaehler manifold K₂ onto an indefinite almost Hermitian manifold K', and show that for this case K' must be an indefinite Kaehler manifold. Then, we derive a relationship between the holomorphic sectional curvatures of K₂ and K'. Finally, we present a classification theorem for a screen generic lightlike submersion, giving the relationship between the sectional curvatures of the total space K₂ and the fibers.

• Journal of Korean Library and Information Science Society
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• v.21
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• pp.459-483
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• 1994

The purpose of the study is to design and implement a prototype expert system for library classification in the literature field of the DDC 20. The system was largely consisted of a knowledge base, an inference engine, a knowledge acquisition facility, an explanation facility and an user interface facility. The knowledge base was represented by inference rules and frames. The name file for authors and titles was designed separately. The forward chaining technique was chosen for the inference engine and the menu-driven dialog technique was also taken for the user interface. The conclusions of the study can be summarized as follows: 1) The difficulty of document classification work is due to the complex and stringent classification rules. Such problems can be considerably alleviated by using the present system. 2) Even the novice with a knowledge about the DDC 20 can easily access the system. And also librarian other than the professional classifier can easily be accustomed to the classification work. 3) The system can be used as an online classification scheme. 4) By adding any local language other than English or Hangeul on the menu screen, the language problem relating classification can be overcome. 5) The system can be employed as the intensification tool for the education of classification as well as library automation.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.29 no.7
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• pp.23-31
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• 2011

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.5
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• pp.584-590
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• 2020

Long-term use of digital screens in daily life can lead to computer vision syndrome including symptoms such as eye strain, dry eyes, and headaches. To prevent computer vision syndrome, it is important to limit screen usage time and take frequent breaks. There are a variety of applications that can help users know the screen usage time. However, these apps are limited because users see various screens such as desktops, laptops, and tablets as well as smartphone screens. In this paper, we propose and evaluate machine learning-based models that detect the screen device in use using color, IMU and lidar sensor data. Our evaluation shows that neural network-based models show relatively high F1 scores compared to traditional machine learning models. Among neural network-based models, the MLP and CNN-based models have higher scores than the LSTM-based model. The RF model shows the best result among the traditional machine learning models, followed by the SVM model.

• Journal of Digital Convergence
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• v.11 no.8
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• pp.331-340
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• 2013

Depaysement, suggested by the well-known surrealist Rene Magritte, has been used for and applied to many media. Application of depaysement through various media such as TV, commercial, and advertisement, attempted to provide interest by deviation from fixed ideas and visual shock, placing common objects in new and strange environment. The study applied screen projection mapping using a transparent screen and objet for different purposes to projection mapping media, applying depaysement to the artwork 'Illusion' in order to suggest visual pleasure, possibility as a new media, and projection mapping using transparent screen and objet. The work cases were suggested by applying expressive methods and effects according to three classifications - modulation of space, combination of conflicting images, and transformation and change of objects - in depaysement, and analyzed by types based on classification of the layout, typography, image, color, and time. Through 'Illusion,' new objet and characteristics of the media are applied and expanded by using projection mapping and depaysement.