• Journal of Broadcast Engineering
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• v.5 no.1
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• pp.102-112
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• 2000

The previous video structuring techniques are mainly limited to shot or shot group level. However, the shot level structure couldn't provide semantics within a video. So, researches on high level structuring are going on for getting over the drawbacks of shot level structure, recently. To overcome the drawbacks of shot level structure, we propose video scene segmentation technique based on color and motion features. For considering various color distribution, each shot is divided into sub-shots based on color feature. A key frame is extracted from each sub-shot. The motion feature in a shot is extracted from MPEG-1 video's motion vector. Moreover adaptive weights based on motion's property in search range are applied to color and motion features. The experiment results of proposed technique show the excellence in view of the over-segmentation and the reflection of semantics, comparing with those of previous techniques. The proposed technique decomposes video into meaningful hierarchical structure and provides video browsing or retrieval based on scene.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.33-39
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• 2005

A mathematical model, GUNBLAST, of blast waves emitted from a gun muzzle is established, and structural response analyses for the blast load are performed. The blast wave can be divided into two kinds of waves, free field and reflected blast waves. In this research, the free field blast wave model is established by the use of a scaling approach, and the reflected blast wave is calculated by using the oblique shock theory and computational fluid dynamic calculation. GUNBLAST is applied to two kinds of structural models. To investigate the effect of the muzzle distance from a structural surface, the blast waves on a plate for various muzzle distances are compared to uniform loads. Moreover, the transient response analysis of an aircraft wing model with a 12.7mm gun is carried out by using MSC/NASTRAN. From the results, it can be shown that the blast wave can cause broad random vibration and high frequency damage to equipments mounted in the aircraft.

• Journal of Engineering Education Research
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• v.22 no.6
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• pp.12-20
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• 2019

The purpose of this study is to development of a teaching-learning model for active learning in engineering education. For this, the adequacy between educational objectives and active learning activities is verified and furthermore an "active learning teaching-learning model" is suggested. This suggested teaching-learning model is expected to supplement weakness of traditional lecture-type teaching-learning activity. Based on the literature review, first, the representative activities of active learning were derived. there are twenty active learning activities, which compose of five of individual learning activity, five of pair-learning activity and five of group-learning activity, and five of alternative- learning activity. In addition, a survey on adequacy between designed active learning activities and learning outcomes were conducted to ten educational experts. Lawshe's content validity calculation method was applied to analyze the validity of this study. Second, five teaching-learning principles, such as thinking, interaction, expression, reflection, and evaluation were derived to develop an "active learning teaching-learning model" which supplements lecture-type classes and then the "TIERA teaching-learning model" which consists of five stages was designed. Finally, based on the survey on educational experts, adequate active learning activities were proposed to apply in each stage of the "TIERA teaching-learning model" and as a result the TIERA model's active learning activities were developed. The result of this study shows that some activities of active learning are appropriate to induce high cognitive learning skills from the learners even in traditional lecture-type classrooms and therefore this study suggests meaningful direction to new paradigm of teaching-learning for engineering education. This study also suggests that instructors of engineering education can turn their traditional teaching-learning activities into dynamic learning activities by utilizing "active learning teaching-learning model".

• Science of Emotion and Sensibility
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• v.8 no.3
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• pp.231-240
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• 2005

The social participation and economic position of the woman come to be high, they are rising to the market as a core consumer and trend inventor leading the fashion. So that, we have to recognize the woman with one axis of product development, it is necessary to the product development and the strategy which it will put woman oriented sensibility in product design. From this research, it reviews the backgrounds from social culture and the economic marketing sides through the digital product recently, it analyzed the features of woman characteristic designs which is embossed the product. Also it connected actual product development, it developed a woman oriented sensibility audio which reflected a woman's consuming trend, life style and the preference product style. It proposed the necessity of woman oriented product development ultimately and researched the product design strategy for the reflection of woman sensibility.

• School Mathematics
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• v.18 no.1
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• pp.105-126
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• 2016

Math classes has been regarded as an independent area of a teacher and his/her students of a particular class. In Recent discussions about the professional development of teachers, for the improvement of practices, the point of view of that the community of teachers must work together is spreading. What are the considerations in organization and operation of learning communities for professional development of teachers? In this study, we analyzed the case of the learning community of math teachers in a Science Academy for the purpose of improving math classes to promote the participation of learners. Research results show that teachers share the principles and goals of mathematics teaching through the learning community. Also, through participation in learning communities, the members were practicing the lessons improved by reflection on the lessons of his/her and their colleagues. These results provide implication that it is important to provide opportunities for objectifying his/her classes through the learning community for a substantial improvement in math classes.

• Atmosphere
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• v.21 no.1
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• pp.123-130
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• 2011

In this study, we have analyzed the radiative characteristics of erythemal ultraviolet-B (EUV-B from 1999 to 2005) over the Korean Peninsula. EUV-B measured at Gangneung, Anmyondo, Mokpo, and Gosan represents the measurements from clean areas and that at Seoul represents from a polluted area. The magnitudes of EUV-B increase in proportion to the latitudinal decrease. Monthly mean variation of EUV-B at noon shows the maximum value of $158.5mWm^{-2}$ in August and the minimum value of $36.4mWm^{-2}$ in December in the clean areas. Seasonal mean diurnal variation of EUV-B shows a peak around noon (12:00 ~ 13:00 hr) and its intensity varies along with a season in order of summer > spring > fall > winter. The maximum value of $56.4mWm^{-2}$ in summer is three times higher than that in winter ($14.3mWm^{-2}$). The value of EUV-B in the polluted area is lower than that in the clean areas, resulting from the effects of the blocking, reflection, and scattering of EUV-B due to high concentrations of PM10. UV-B is an essential element to synthesize vitamin D in human body. 200 IU(International Unite) of vitamin D can be formed by an exposure of 6-10% of body surface area to 0.5 MED(Minimal Erythemal Dose). In order to form vitamin D, the calculated exposure times to EUV-B are 15 min. in spring, 12 min. in summer, 18 min. in fall, and 37 min. in winter for the clean areas and 16, 16, 24, and 37 min. for the polluted area.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12A
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• pp.1233-1241
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• 2008

We design, fabricate, and measure a MIMO antenna system mountable on a small PCB (such as UMPC). The proposed antenna system accommodates three radiation elements on the PCB area of $40mm\;{\times}\;100mm$. Two of them employ a slot type and one uses a modified monopole with an inverted L shape expecting high isolation and polarization purity. The bandwidth of each proposed MIMO antenna ranges from 80MHz and 200MHz at the center frequency of 1.8 GHz. The isolations between ports have been found to be greater than 10dB over the interested frequency band. Besides, the proposed MIMO system has been evaluated in terms of ARC(Active Reflection Coefficient, TARC(Total ARC), correlation, MEG, and etc. The envelope correlation is calculated to be much less than 0.04 and the ratio of the mean effective gain(MEG) between the antennas is found to be close to unity.

• The Journal of the Acoustical Society of Korea
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• v.24 no.3
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• pp.171-177
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• 2005

The effect of diffusers on Early Stage Support (ST1) in a concert hall was investigated at 8 positions in a 1:25 stage scale model. Experiments were carried out when the stage floor was covered with and without absorption cloth to investigate the effect of stage floor reflection (absorption coefficient - 0.6 at 500Hz). To find out the effect of stage wall. three types of wall diffusers were used. As a result. absorption cloth on stage floor reduced the ST1 values at high frequency. but the average value of ST1 was not changed. Three types of stage wall diffusers were revealed as unaffecting. but it was observed that the ST1 values varied to positions of stage. The ST1 values were evenly distributed when hemisphere diffusers were used. Therefore. the use of floor absorption did not have much effect on the ST1 values, and the diffusers had some effect on the distribution of the ST1 values.

• Korean Journal of Optics and Photonics
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• v.9 no.6
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• pp.380-384
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• 1998

As the development of ultrahigh power laser system, the laser mirrors must require high-resistant and effectively cooled. So, the study for the optical multilayer systems having large thermal diffusivity become important. In this study, we designed and fabricated two-layer anti-reflection (AR) optical coating samples, in different evaporation conditions of coating speeds (10, 20 $\AA$/s) and substrate temperatures (50, 100, 150, 20$0^{\circ}C$), using two dielectric materials $MgF_2$ and ZnS which have different refractive indices and measured the through-plane thermal diffusivity by using photoacoustic effect. The optical thicknesses of $MgF_2$ and ZnS layer were fixed as 5/4λ (λ=514.5nm) and λ, respectively, and the thermal diffusivity of the samples fabricated in the different conditions was obtained from the measured amplitude of photoacoustic signals by changing chopping frequency of $Ar^+$ layer beam. The results told us that the thermal diffusivity of the sample fabricated in the condition of 10 $\AA$/s and 15$0^{\circ}C$ showed the largest value.

• Journal of the Korean Solar Energy Society
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• v.29 no.4
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• pp.28-33
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• 2009

In 2008, the global photovoltaic(PV) market reached 5.6GW and the cumulative PV power installed totalled almost 15GW compared to 9GW in 2007. Due to a favourable feed-in-tariff, Korea emerged in 2008 as the 4th largest PV market worldwide. PV power installation rose 495.5 percent to 268MW in 2008 compare to 45MW in 2007. Building integrated photovoltaic(BIPV) has the potential to become a major source of renewable energy in the urban environment. BIPV has significant influenced on the reflection by rear materials such as white back sheet and the heat transfer through the building envelope because of the change of the thermal resistance by adding or replacing the building elements. In this study, to use as suitable building materials into environmentally friendly house like green home, characteristic analysis of BIPV module according to rear materials achieved. Electrical output of PV module with white back sheet is high about 10% compared to other pv module because of 83% reflectivity of white back sheet compared to 8.4% reflectivity of other PV modules with different rear materials(black back sheet and glass). In the result of outdoor experiment during a year, electrical output of four different PV module is decreased about 3.72%.