• 한국IT서비스학회:학술대회논문집
• /
• 2003.11a
• /
• pp.637-642
• /
• 2003

현재 각 기업 및 기관에서 구축하고 있는 디지털 콘텐츠는 HTML을 비롯한 다양한 형식의 멀티미디어로 작성되어 있다. 따라서 타 기관에 전시된 콘텐츠 정보를 검색하거나 연동하기는 불가능하다. 뿐만 아니라 시스템을 확장하기 위해서는 전체 시스템을 교체해야하는 문제도 파생될 수 있다. 그러나 본 연구에서 제안하는 플랫폼은 기존 레거시(Legacy) 어플리케이션을 수정하지 않더라도 쉽게 신 시스템과 연동이되고 타 시스템과도 연동이된다. 또한 CORBA에 기반한 부하 분산 기법과 분산 처리기법을 도입하여 하나의 시스템에 과부하가 발생하여 전체시스템의 성능이 저하되는 문제를 방지하고 안정성을 보장하기 위하여 Fail-over 기능을 제공한다. 또한 SyncML 기법을 도입하여 여러 종류의 DBMS를 사용하는 타 기관과의 콘텐츠 실시간 공유를 지원한다. 이로써 콘텐츠를 쉽게 저장 및 유통할 수 있는 기반 환경을 제공한다.

• Bulletin of the Korean Chemical Society
• /
• v.9 no.1
• /
• pp.36-40
• /
• 1988

The time correlation functions of concentration fluctuations due to the random forces near the steady state are evaluated for a general two-component nonlinear chemical system by solving the corresponding two dimensional Fokker-Planck equation. The approximate method of solving the Fokker-Planck equation is based on the eigenfunction expansion and the corresponding eigenvalues for both the linear and nonlinear Fokker-Planck operators are obtained near the steady state. The general results are applied to the Lotka model near the oscillatory marginal steady state and the comparison is made between linear and nonlinear cases.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.1
• /
• pp.47-51
• /
• 1991

Spin-lattice relaxation of methyl protons in 2,6-dichlorotoluene and N-methyl phthalimide, each dissolved in CDCl$_3$, has been studied at 34$^{\circ}$C and the contribution from spin-rotation interaction to the relaxation process has been separated from that due to dipole-dipole interactions among methyl protons. The results show that the spin-rotational contributions to the initial rate of relaxation in 2,6-dichlorotoluene and N-methyl phthalimide amount to 18 and 31%, respectively, of the total relaxation rate at 34$^{\circ}$C. The method of separating the spin-rotational contribution from that of dipolar interactions adopted in this paper is based on the well known fact that in an A$_3$ spin system such as methyl protons in liquid phase dipolar relaxation mechanism gives non-exponential decay of the z-component of total magnetization of protons while the random field fluctuation such as spin-rotational mechanism causes exponential decay.

• Computers and Concrete
• /
• v.18 no.2
• /
• pp.179-199
• /
• 2016

The aim of this study is to investigate arrival direction effects of travelling waves on non-linear seismic response of arch dams. It is evident that the seismic waves may reach on the dam site from any direction. Therefore, this study considers the seismic waves arrive to the dam site with different angles, ${\theta}=0^{\circ}$, $15^{\circ}$, $30^{\circ}$, $45^{\circ}$, $60^{\circ}$, $75^{\circ}$, and $90^{\circ}$ for non-linear analysis of arch dam-water-foundation interaction system. The N-S, E-W and vertical component of the Erzincan earthquake, on March 13, 1992, is used as the ground motion. Dam-water-foundation interaction is defined by Lagrangian approach in which a step-by-step integration technique is employed. The stress-strain behavior of the dam concrete is idealized using three-dimensional Drucker-Prager model based on associated flow rule assumption. The program NONSAP is employed in response calculations. The time-history of crest displacements and stresses of the dam are presented. The results obtained from non-linear analyses are compared with that of linear analyses.

• International Journal of Computer Science & Network Security
• /
• v.21 no.7
• /
• pp.169-172
• /
• 2021

Based on the scientific and pedagogical analysis of the theory and experience of teaching computer science disciplines, the didactic mechanism for ensuring the continuity of the average (full) general and higher professional education of economists for practical implementation innovative technology of personal experience foundation. The pedagogical conditions for the formation of information competence, including laboratory, design, research work, the use of active teaching methods for acquiring management skills in production and activities of the enterprise. An indispensable requirement for the conditions for the implementation of basic of educational programs is the assessment of competencies. With this the goal was to develop criteria and levels of formation information competence of future economists and carried out complex diagnostics.

• Journal of Multimedia Information System
• /
• v.5 no.4
• /
• pp.221-228
• /
• 2018

Skin-color information is not sufficient for palmprint segmentation in complex scenes, including mobile environments. Traditional active shape model (ASM) combines gray information and shape information, but its performance is not good in complex scenes. An improved ASM method is developed for palmprint segmentation, in which Perux method normalizes the shape of the palm. Then the shape model of the palm is calculated with principal component analysis. Finally, the color likelihood degree is used to replace the gray information for target fitting. The improved ASM method reduces the complexity, while improves the accuracy and robustness.

• Journal of the Korea Society of Computer and Information
• /
• v.24 no.2
• /
• pp.217-225
• /
• 2019

In this paper, we proposed comparison of software education units according to 2015 Revised National Curriculum. Comparative analysis of 6 Practical Arts textbooks was conducted especially on the software education units. The analysis criteria were decided to be unit system, unit structure, learning objectives, the way of placing contents, activities, supporting materials, providing resources, and evaluation. As a result, the software education units have secured a lot of quantity compared to the total number of units. And the affective domain of the learning objectives is shown to be lacking. All the textbooks were uniformly arranged the component of contents described in 2015 revised national curriculum. Cooperative activities are strengthened compared to the previouse curriculum. On the other hand, evaluations have a large variation among textbooks and some have fewer types.

• Journal of Multimedia Information System
• /
• v.6 no.3
• /
• pp.155-164
• /
• 2019

We intended to confirm that microwave attenuation by tree leaves is strongly linked to water content in leaves. We sampled natural broadleaves, including Japanese cinnamon, and investigated their effects on the microwave (3 to 20 GHz) frequency characteristics using a network analyzer. Experiments determined that microwave attenuation by foliage increases as a linear function of frequency per unit weight (gram). As the frequency increases, the spatial resolution increases, but the phase difference (imaginary component) increases. So we solved the dispersion of phase difference by sweeping the frequency and taking the intermediate value. Based on these experimental results, we developed a microwave scanner on 10Ghz to describe foliage moisture as a image and to enable assessments of leaf condition. Photosynthesis is the process whereby plants synthesize oxygen and sugars from carbon dioxide and water, thereby converting light energy into chemical energy. Since water is a major parameter of photosynthesis, the quantity of water accumulated inside a leaf reflects leaf health. The equipment described here and related microwave technologies will help assess the capacity of leaves to absorb atmospheric carbon dioxide.

• Journal of Power Electronics
• /
• v.19 no.2
• /
• pp.591-601
• /
• 2019

With the development of renewable energy, grid-connected inverter technology has become an important research area. When compared with traditional silicon IGBT power devices, the silicon carbide (SiC) MOSFET shows obvious advantages in terms of its high-power density, low power loss and high-efficiency power supply system. It is suggested that this technology is highly suitable for three-phase AC motors, renewable energy vehicles, aerospace and military power supplies, etc. This paper focuses on the SiC MOSFET behaviors that concern the parasitic component influence throughout the whole working process, which is based on a three-phase grid-connected inverter. A high-speed model of power switch devices is built and theoretically analyzed. Then the power loss is determined through experimental validation.

• KEPCO Journal on Electric Power and Energy
• /
• v.4 no.2
• /
• pp.47-53
• /
• 2018

VSC technology is now well established in HVDC and is, in many respects, complementary to the older Line Commutated Converter (LCC) technology. Despite the various advantages of VSC technology, VSC HVDC stations have higher power losses than LCC stations. Although the relative advantages and disadvantages are well known within the industry, there have been very few attempts to quantify these factors on an objective basis. This paper describes methods to determine the operating losses of every component in the valve of VSC-HVDC system. The losses of the valve, including both conduction losses and switching losses, are treated in detail.