• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1259-1260
• /
• 2007

In this paper, the inductive power collector using electromagnetic induction for vehicle such as the electric railway vehicle system is suggested and some ideas for power collector design to improve the power transfer performance are presented. The inductive power of secondary part is related to amount of linked flux to secondary part by the length of air-gap, which is expected by such a system parameter as mutual inductance. This paper will study for the transfer characteristic of power from input to output and equation including mutual inductance. And also, effect of leakage inductance variation of inductive power collector according to structure of winding was considered.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.1
• /
• pp.240-249
• /
• 1994

The basic experiments for designing the effective gas turbine combustor were performed. There are several factors that define the characteristics of gas turbine combustor. Among them, experiment was focused on swirl effects by three types of swirler with different swirl numbers(0.0, 0.38, and 0.62). Particularly, an interest was concentrated on primary zone where the flame characteristics of total combustor was dominated strongly and secondary zone where the remaining unburned gas was reacted again or cooling effect was done according to degree of swirl intensity. For this study, following measurements have been carried out, that is, time mean and fluctuating temperature, exhaust gas composition including NO concentration, and ion current. From this study, it was found that swirl intensity affects largely not only flame style but also emission formation, furthermore that it is important to select proper swirl intensity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2001.11b
• /
• pp.1317-1322
• /
• 2001

What changes in the eigen values and eigen functions are produced if the boundary surface S is no longer rigid but has a specific acoustic admittance which may vary from point to point on S. In this paper, changes in eigen values and eigen functions are derived by using Kirchhoff-Helmholtz integral equation. And acoustic potential energy, which is representative measure describing the physical quantity in cavity, is defined. Acoustic potential energy can be divided into primary one and secondary one. Primary one is the acoustic potential energy through unchanged eigen functions, and secondary one is through changed eigen functions. Using these two term, we can find the eigenvalue problem, which gives the control performance when the boundary condition is changed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.482-485
• /
• 2004

On the basis of theoretical studies on the effect of the cylinders attached to semi-infinite screens, the tangential sound power-transport parallel to the surface of the attached cylinder is minimized by means of a secondary sound field, which is generated from a part of the attached cylinder. The numerical study shows the possibility of deflecting the incident sound by minimizing the acoustic surface impedance of the upper sections. The acoustical shadow region was more pronounced in both near- and far-field compared to the passive case with rigid surface, i.e. without active control. For a relatively wide frequency range it was possible to enhance shielding effects only with few secondary sources and error microphones. In this paper effects of some control parameters on the actively controlled sound field near the top edge of noise barriers are studied. Results of numerical study and model measurements are shown and discussed.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.26 no.1
• /
• pp.239-260
• /
• 2000

The raw materials requiring new technology have been introduced to the market as highly functional cosmetics have been popularized recently. The doublesphere which is the new capsulation is thus born. The deublesphere is double-layered capsulation of which the primary film is the nanocapsulation of liposome and the secondary film is the visible capsulation. The main component of the primary film is lecithin and that of the secondary film is alginlcarrageenanslagarfcellulose. The doublesphere is characterized by that it is possible to keep active beautifying components stable and to improve the moisturizing effect, penetration power into the skin, roughness of the skin, etc. in view of its efficacy and effects since it is double-layered capsulation. The doublesphere-retinol is made in order to measure the stability, efficacy, and effects in the present study.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• v.22 no.4
• /
• pp.217-239
• /
• 2018

This paper examined the MHD and thermal behavior of unsteady mixed convection flow of a rotating fluid in a porous parallel plate channel in the presence of Hall current and heat source. The exact solutions of the concentration, energy and momentum equations are obtained. The influence of each governing parameter on non dimensional velocity, temperature, concentration, skin friction coefficient, rate of heat transfer and rate of mass transfer at the porous parallel plate channel surfaces is discussed. During the course of numerical computation, it is observed that as Hall current parameter and Soret number at the porous channel surfaces increases, the primary and secondary velocity profiles are increases while the primary and secondary skin friction coefficients are increases at the cold wall and decreases at the heated wall. In particular, it is noticed that a reverse trend in case of heat source parameter.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2019.07a
• /
• pp.289-292
• /
• 2019

매년 수많은 게임이 출시되면서 유저들이 게임을 즐기는 방법도 다양해졌다. 이중 게임을 바탕으로 유저가 창의성을 더해 2차 저작물을 제작하는 방법이 주류를 이루고 있다. 자신이 좋아하는 게임에 대한 애정을 표현하는 한 가지 방법이라고 할 수 있으며, 이러한 2차 창작 활동은 유저의 심리적인 만족감을 채워주는 것과 동시에 게임의 홍보기능도 한다. 하지만 게임사마다 2차 저작물과 관련된 규제가 다르며 유저들은 그 규제를 모르는 경우가 많아 원저작자의 권리를 침해하기도 한다. 본 논문에서는 2차 창작 활동에 대한 유저의 의견과 게임사의 정책 및 대응을 조사하고 유저와 게임사 모두가 만족할 수 있는 방안을 제시하고자 한다.

• Educational Technology International
• /
• v.22 no.1
• /
• pp.23-55
• /
• 2021

Under the context of the recent curriculum reform in Mongolia emphasizing technology integration in schools, the main purpose of this study was to examine external and internal factors that influence teachers' use of technology. This study aimed to investigate structural relationships between school support, technology use, and TPACK (Technological Pedagogical and Content Knowledge) among Mongolian secondary school teachers. This study was conducted with 208 secondary school teachers in Ulaanbaatar, Mongolia. Data were collected through an instrument that measures three factors: teachers' use of technology, TPACK, and school support. The results indicate that TPACK has a partial mediation effect on the relationship between school support and the use of technology. The contribution of this study lies that it examines the complex relationships between internal and external factors affecting teachers' technology integration, especially among Mongolian teachers who are less researched in the existing literature.

• International Journal of Computer Science & Network Security
• /
• v.21 no.7
• /
• pp.93-102
• /
• 2021

This study aimed to test method on the accuracy of estimating the items parameters and ability, using the Three Parameter Logistic. To achieve the objectives of the study, an achievement test in chemistry was constructed for third-year secondary school students in the course of "natural sciences". A descriptive approach was employed to conduct the study. The test was applied to a sample of (507) students of the third year of secondary school in the "Natural Sciences Course". The study's results revealed that the (EAP) method showed a higher degree of accuracy in the estimation of the difficulty parameter and the abilities of persons higher than the MML method. There were no statistically significant differences in the accuracy of the parameter estimation of discrimination and guessing regarding the difference of the two methods: (MML) and (EAP).

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2022.01a
• /
• pp.345-348
• /
• 2022

본 논문에서는 유체 시뮬레이션(Fluid simulation)중 화염에서 표현되는 불똥 입자(Fire-flake particle)의 생성, 움직임과 삭제를 효율적으로 학습하고 표현할 수 있는 인공지능 기법에 대해 소개한다. 유체 시뮬레이션을 계산하기 위해서는 일반적으로 수치해석학과 같은 학문의 이해가 필요하며 불똥이나 거품과 같은 유체의 2차 효과(Secondary effect)는 기반유체(Underlying fluids)를 통해 추출되기 때문에 복잡하고 계산양이 많아진다. 이러한 문제를 완화하고자 본 논문에서는 인공신경망을 이용한 분류 모델 학습을 통해 격자 내에서 표현되어야 하는 불똥 입자의 생성을 학습하고, 다항 회귀 모델 학습을 통해 불똥 입자의 움직임을 예측한다. 또한, 불똥 입자가 삭제되어야하는 상태를 네트워크 학습을 통해 얻어내며, 수명(Lifespan) 임계값 조절하여 다양한 장면에서 불똥을 제어할 수 있다. 결과적으로 화염의 움직임을 기반으로 불똥의 움직임을 복잡한 수학식이나 디자이너에게 의존하지 않고 인공지능 학습을 통해 쉽게 제어하고 예측하는 결과를 보여준다.