• Journal of the Korean Society of Propulsion Engineers
• /
• v.1 no.2
• /
• pp.22-31
• /
• 1997

We developed a general purpose program for the analysis of flows in the combustor with recirculating flow regime and simulated the flows. The program uses non-staggered grids based on finite volume method and the primitive variables are cartesian velocities. The combustion model is irreversible one step reaction with infinite chemistry The Favre averaged governing equations are considered and the clipped gaussian distribution is considered as a probability density function of the conserved scalar. We calculated turbulent diffusion flame with recirculating flow regime. Simulation shows two recirculating regions like experimental results. Velocity, turbulent kinetic energy, temperature and concentration distribution in simulation agree well with experimental data.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.164-165
• /
• 2011

본 논문에서는 전력계통의 동요시 넓은 범위의 안정영역을 확보하고 발전기의 댐핑을 향상시킬 수 있는 새로운 조속기 제어기를 제안한다. 전력계통의 안정도는 대부분 고장기간 동안 발전기에 축적된 잉여 운동에너지에 크게 영향을 받기 때문에 이러한 잉여에너지에 대한 효과적인 제어는 조속기를 통해 이루어 질 수 있으며, 전력계통 안정도를 향상시킬 수 있는 가장 직접적인 방법이다. 제안된 Output Feedback 제어기는 모든 주파수 조절상수(R)에 대해 넓은 범위의 안정성을 보장하고, 미분기를 대신할 수 있도록 발전기 동요방정식을 적용한다.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2011.08a
• /
• pp.191-191
• /
• 2011

최근 투명전극 연구는 태양전지 및 디스플레이, LED 등 많은 분야에서 응용되며 또한 기술 개발이 활발하다. 그 중 전기 전도도가 우수하면서 밴드갭이 2.5 eV 이상으로 가시광 영역에서 투명하기 때문에 디스플레이의 투명전극으로 ITO (Indium Tin Oxide)가 많이 사용되고 있다. 본 실험에서는 RF magnetron sputtering법을 이용한 ITO의 증착시 산소 유량을 달리하여 제작한 박막의 Energy Band Structure를 ${\gamma}$-FIB system을 이용하여 측정하였다. ITO에 이온화 에너지가 24.5 eV인 He Ion source를 주사하였을 때 Auger self-convolution을 통해 이차전자의 운동 에너지 분포를 구하고, 이를 통해 ITO 내의 Energy Band Structure를 실험적으로 측정하였다.

• The Journal of the Convergence on Culture Technology
• /
• v.6 no.4
• /
• pp.9-14
• /
• 2020

This study examined whether the integrated education science and resource e-book developed for students with disabilities were properly implemented in terms of universal design for learning. For analysis, "Teaching and learning materials for inclusive education of students with disabilities: grade 3~6 sciences", which were instructional adaptation, were selected for students with disabilities who are unable to learn the contents of general textbooks for the 3rd to 6th grade of the elementary school science course in the 2015 revised curriculum. The science grades are composed of 40 units, including basic science inquiry, matter, life, kinetic and energy, earth and universe. The content analysis standard was based on detailed items of 9 definitions according to the 3 principles of UDL presented in CAST (2018). As a result of the study, the strategy network was the largest among the UDL principles. As for the domain of the science curriculum, the kinetic and energy was the most common. As UDL detailed items, informations presentation suitable for learners was most frequent in cognitive network. Various ways of searching for data, was most frequent in strategies network. Diverse materials optimized difficulty of contents was most frequent in affective network.

• Composites Research
• /
• v.26 no.3
• /
• pp.175-181
• /
• 2013

The evaluation and prediction for the absorbed energy, residual velocity, and impact damage are the key things to characterize the impact behavior of composite laminated panel subjected to high-velocity impact. In this paper, the method to predict the residual velocity and the absorbed energy of Carbon/Epoxy laminated panel subjected to high velocity impact are proposed and examined by using quasi-static perforation test and high-velocity impact test. Total absorbed energy of specimen due to the high-velocity impact can be grouped with static energy and kinetic energy. The static energy are consisted of energy due to the failure of the fiber and matrix and static elastic energy, which are related to the quasi-static perforation energy. The kinetic energy are consisted of kinetic energy of moving part of specimen, which are modelled by three modified kinetic model. The high-velocity impact test were conducted by using air gun impact facility and compared with the predicted values. The damage area of specimen were examined by C-scan image. In the high initial impact velocity above the ballistic limit, both the static energy and the kinetic energy are known to be the major contribution of the total absorbed energy.

• The KIPS Transactions:PartB
• /
• v.15B no.3
• /
• pp.197-204
• /
• 2008

It is well known that the tracking a certain person is a vary needed technic in the humanoid robot. In robot technic, we should consider three aspects that is cloth color matching, face recognition and motion analysis. Because a robot technic use some sensors, it is many different with the robot technic to track a certain person through the CCTV images. A system speed should be fast in CCTV images, hence we must have small calculation numbers. We need the statistical variable for color matching and we adapt the eigen-face for face recognition to speed up the system. In this situation, motion analysis have to added for the propose of the efficient detecting system. But, in many motion analysis systems, the speed and the recognition rate is low because the system operates on the all image area. In this paper, we use the moving energy only on the face area which is searched when the face recognition is processed, since the moving energy has low calculation numbers. When the proposed algorithm has been compared with Girondel, V. et al's method for experiment, we obtained same recognition rate as Girondel, V., the speed of the proposed algorithm was the more faster. When the LDA has been used, the speed was same and the recognition rate was better than Girondel, V.'s method, consequently the proposed algorithm is more efficient for tracking a certain person.

• Journal of Science Education
• /
• v.36 no.2
• /
• pp.394-407
• /
• 2012

This study analyzed the result of the National Assessment of Educational Achievement (NAEA) in a Grade 9 Science class. The study first found that the ratio of below basic achievement was 8.1 percent. This means that a large number of middle school students have not reached basic scientific literacy. Second, the ratio of male students in the below basic level was 10.4 percent, which was double the ratio of female students at 5.5 percent. Third, according to the analysis of achievement by gender, female students outperformed male students. In addition, the female students' standard deviation was smaller than that of the male students, and their scaled scores were distributed nearer the average than that of the male students. Furthermore, analysis of achievement by content domains indicated that females outperformed in all content domains including motion and energy, materials, life, and earth sciences. Showing a similar tendency in the behavior domains, females outperformed males in all behavior domains except the understanding domain. Last, for achievement by living area, students living in the middle and small cities showed the highest scaled score, 196.81. Whereas the average scaled score of the students living in the big cities was 196.15; that of the students living in rural areas was 194.86. With respect to the standard deviation, big cities had the largest, 33.73. That of middle and small cities was 33.70, and of rural areas was 32.92. Although students in cities showed higher achievement in science compared to students in rural areas, they had a bigger gap in academic achievement.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.18 no.4
• /
• pp.291-297
• /
• 2015

The wave spectrum was generated from wave data measured at the Chagwi-do site in Jeju, where a 10MW class floating wave-offshore wind hybrid power generation system will be installed. The latching control technology (Sheng et al.[2015]) was applied in order to improve the extracted power from WEC (Wave Energy Converter), which is heaving in corresponding irregular waves. The peak period as a representative value of irregular waves was used when we determined the latching duration. From the numerical results in the time-domain analysis, the latching control technology can significantly improve the extracted power about 50%.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.35 no.12
• /
• pp.1579-1584
• /
• 2011

This paper discusses an energy system that can convert wave energy into electrical energy. This wave energy generation system is movable and has 12 arms and one generator. A multibody dynamic model for this system is established by using kinematic constraints. A gear mechanism, several kinematic constraints, and force elements are included in the model. Wave forces are obtained numerically from the time domain formulation based on the Morison equation. The MSC/ADAMS program is employed to carry out dynamic analysis of the wave energy generation system. The dynamic behavior responses of this system are analyzed for design verification. According to the results of the dynamic analysis, the yaw motion is relatively stable and kinetic energy sufficient to generate electrical energy is obtained when the wave height exceeds 1m.

• Journal of the Society of Naval Architects of Korea
• /
• v.36 no.3
• /
• pp.15-21
• /
• 1999

The flow characteristics around KRISO 300K VLCC double-body model have been experimentally investigated in a closed-type subsonic wind tunnel. The local mean velocity and turbulence statistics including turbulent intensity. Reynolds shear stress and turbulent kinetic energy were measured using a x-type hot-wire probe. The measurements were carried out at several transverse stations of the stern and near wake regions. The surface flow was visualized using on oil-film technique to see the flow pattern qualitatively. The flow in the stern and near wake region revealed complicated three-dimensional flow characteristics. The VLCC model shows a hook-shaped wake structure behind the propeller boss in the main longitudinal vortex region. The thin boundary layer at midship was increased gradually in thickness over the stern and evolved into a full three-dimensional turbulent wake.