• Journal of The Korean Astronomical Society
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• v.12 no.1
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• pp.41-70
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• 1979

From $B\ddot{o}hm$-Vitense's atmospheric model calculations, the relations, [$T_e$, (B-V)] and [B.C, (B-V)] with respect to heavy element abundance were obtained. Using these relations and evolutionary model calculations of Rood, and Sweigart and Gross, analytic expressions for some physical parameters relating to the C-M diagrams of globular clusters were derived, and they were applied to 21 globular clusters with observed transition periods of RR Lyrae variables. More than 20 different parameters were examined for each globular cluster. The derived ranges of some basic parameters are as follows; $Y=0.21{\sim}0.33,\;Z=1.5{\times}10^{-4}{\sim}4.5{\times}10^{-3},\;age,\;t=9.5{\sim}19{\times}10^9$ years, mass for red giants, $m_{RG}=0.74m_{\odot}{\sim}0.91m_{\odot}$, mass for RR Lyrae stars, $m_{RR}=0.59m_{\odot}{\sim}0.75m_{\odot}$, the visual magnitude difference between the turnoff point and the horizontal branch (HB), ${\Delta}V_{to}=3.1{\sim}3.4(<{\Delta}V_{to}>=3.32)$, the color of the blue edge of RR Lyrae gap, $(B-V)_{BE}=0.17{\sim}0.21=(<(B-V)_{BE}>=0.18),\;[\frac{m}{L}]_{RR}=-1.7{\sim}-1.9$, mass difference of $m_{RR}$ relative to $m_{RG},(m_{RG}-m_{RR})/m_{RG}=0.0{\sim}0.39$. It was found that the ranges of derived parameters agree reasonably well with the observed ones and those estimated by others. Some important results obtained herein can be summarized as follows; (i) There are considerable variations in the initial helium abundance and in age of globular clusters. (ii) The radial gradient of heavy element abundance does exist for globular clusters as shown by Janes for field stars and open clusters. (iii) The helium abundance seems to have been increased with age by massive star evolution after a considerable amount (Y>0.2) of helium had been attained by the Big-Bang nucleosynthesis, but there is not seen a radial gradient of helium abundance. (iv) A considerable amount of heavy elements ($Z{\sim}10{-3}$) might have been formed in the inner halo ($r_{GC}$<10 kpc) from the earliest galactic co1lapse, and then the heavy element abundance has been slowly enriched towards the galactic center and disk, establishing the radial gradient of heavy element abundance. (v) The final galactic disk formation might have taken much longer by about a half of the galactic age than the halo formation, supporting a slow, inhomogeneous co1lapse model of Larson. (vi) Of the three principal parameters controlling the morphology of C-M diagrams, it was found that the first parameter is heavy clement abundance, the second age and the third helium abundance. (vii) The globular clusters can be divided into three different groups, AI, BI and CII according to Z, Y an d age as well as Dickens' HB types. BI group clusters of HB types 4 and 5 like M 3 and NGC 7006 are the oldest and have the lowest helium abundance of the three groups. And also they appear in the inner halo. On the other hand, the youngest AI clusters have the highest Z and Y, and appear in the innermost halo region and in the disk. (viii) From the result of the clean separations of the clusters into three groups, a three dimensional classification with three parameters, Z, Y and age is prsented. (ix) The anomalous C-M diagrams can be expalined in terms of the three principal parameters. That is, the anomaly of NGC 362 and NGC 7006 is accounted for by the smaller age of the order of $1{\sim}2{\times}10^9$ years rather than by the helium abundance difference, compared with M 3. (x) The difference in two Oosterhoff types I and II can be explained in terms of the mean mass difference of RR Lyrae variables rather than in terms of the helium abundance difference as suggested by Stobie. The mean mass of the variables in Oosterhoff type I clusters is smaller by $0.074m_{\odot}$ which is exactly consistent with Rood's estimate. Since it was found that the mean mass of RR Lyrae stars increases with decreasing Z, the two Oosterhoff types can be explained substantially by the metal abundance difference; the type II has Z<$3.4{\times}10^{-4}$, and the type I has higher Z than the type II.

• Journal of The Korean Association For Science Education
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• v.37 no.6
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• pp.1025-1035
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• 2017

The purposes of this study are to analyze the merits and limits of flipped learning by suggesting the ALP model for efficient application and to test the effects of the new ALP model. The process of new model and program development is based on ADDIE in this study. This study consists of two steps. First through literature research on the difficulties of the flipped learning, the elements are extracted to develop new model. Second, these elements were placed according to the teaching and learning flow, which resulted in the procedures. As a result, the ALP model was developed. The ALP model is a new model for applying teaching and learning methods for efficient application of the flipped learning. This model was applied to elementary science classes to test its effects in scientific communication skill. Interviews and cognitive survey were also conducted to collect additional information. The results of this study are as follows: There were various difficulties in flipped learning. Based on literature research results, the ALP model and the science programs for elementary students have been developed. The experimental group showed statistically meaningful improvement in scientific communication skill. The scientific communication skill has two subcategories: the forms and the types. According to the form analysis results, the experimental group showed a statistically meaningful improvement in the form of Table and Picture, but not in the form of Writing and Number. With the same reason given previously, this study confirmed that the application of ALP model improves the students' visual form communication skills such as Table and Picture better than reading form communication skills such as Writing and Number. According to the type analysis results, the experimental group showed a statistically meaningful improvement in "the scientific insistence" type, and "the justification" which is the sub element of "the scientific insistence" type. With this reason, this study suggests that the class applied ALP model gives students more time and opportunities to learn. Though the survey and interviews about the student's awareness of the class with applied the ALP model, this study showed that students actively exchanged their opinions in the class with applied ALP model.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.3
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• pp.384-391
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• 2012

In this paper, reinforced concrete structures are modeled and analyzed. Reinforced concrete has been an essential element in the construction and one that is provided for shielding effectiveness at particular frequencies by rebar placed as a set up in the form of a grid. Using commercial 3-dimensional electromagnetic(3D EM) tool to analyze the reinforced concrete structure, the procedure of analysis for reinforced concrete is computed by dividing concrete, rebar and entire reinforced concrete. The spacing of rebar is bigger, transmission coefficient is higher and the diameter of rebar is bigger, transmission coefficient is lower. Also, in case of two layers is analyzed by gap of layers. Using single layer rebar that thickness of rebar given by 10, 20 and 30 mm have transmission coefficient of -1.89, -2.73 and -4.76 dB/10 cm at 500 MHz. Also, two layers rebar obtain -1.89, -2.73 and -4.76 dB/10 cm for same conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.115-116
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• 2012

The demand for flexible electronic systems such as wearable computers, E-paper, and flexible displays has increased due to their advantages of excellent portability, conformal contact with curved surfaces, light weight, and human friendly interfaces over present rigid electronic systems. This seminar introduces three recent progresses that can extend the application of high performance flexible inorganic electronics. The first part of this seminar will introduce a RRAM with a one transistor-one memristor (1T-1M) arrays on flexible substrates. Flexible memory is an essential part of electronics for data processing, storage, and radio frequency (RF) communication and thus a key element to realize such flexible electronic systems. Although several emerging memory technologies, including resistive switching memory, have been proposed, the cell-to-cell interference issue has to be overcome for flexible and high performance nonvolatile memory applications. The cell-to-cell interference between neighbouring memory cells occurs due to leakage current paths through adjacent low resistance state cells and induces not only unnecessary power consumption but also a misreading problem, a fatal obstacle in memory operation. To fabricate a fully functional flexible memory and prevent these unwanted effects, we integrated high performance flexible single crystal silicon transistors with an amorphous titanium oxide (a-TiO2) based memristor to control the logic state of memory. The $8{\times}8$ NOR type 1T-1M RRAM demonstrated the first random access memory operation on flexible substrates by controlling each memory unit cell independently. The second part of the seminar will discuss the flexible GaN LED on LCP substrates for implantable biosensor. Inorganic III-V light emitting diodes (LEDs) have superior characteristics, such as long-term stability, high efficiency, and strong brightness compared to conventional incandescent lamps and OLED. However, due to the brittle property of bulk inorganic semiconductor materials, III-V LED limits its applications in the field of high performance flexible electronics. This seminar introduces the first flexible and implantable GaN LED on plastic substrates that is transferred from bulk GaN on Si substrates. The superb properties of the flexible GaN thin film in terms of its wide band gap and high efficiency enable the dramatic extension of not only consumer electronic applications but also the biosensing scale. The flexible white LEDs are demonstrated for the feasibility of using a white light source for future flexible BLU devices. Finally a water-resist and a biocompatible PTFE-coated flexible LED biosensor can detect PSA at a detection limit of 1 ng/mL. These results show that the nitride-based flexible LED can be used as the future flexible display technology and a type of implantable LED biosensor for a therapy tool. The final part of this seminar will introduce a highly efficient and printable BaTiO3 thin film nanogenerator on plastic substrates. Energy harvesting technologies converting external biomechanical energy sources (such as heart beat, blood flow, muscle stretching and animal movements) into electrical energy is recently a highly demanding issue in the materials science community. Herein, we describe procedure suitable for generating and printing a lead-free microstructured BaTiO3 thin film nanogenerator on plastic substrates to overcome limitations appeared in conventional flexible ferroelectric devices. Flexible BaTiO3 thin film nanogenerator was fabricated and the piezoelectric properties and mechanically stability of ferroelectric devices were characterized. From the results, we demonstrate the highly efficient and stable performance of BaTiO3 thin film nanogenerator.

• Informatization Policy
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• v.24 no.2
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• pp.43-67
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• 2017

In 2015, Korea won the first place among 30 countries in Open, Useful, and Reusable (OUR) Data Index, which is an OECD's open government data indicator. On the other hand, Korea was ranked the 17th among 86 countries in Open Data Barometer (ODB) of World Wide Web Foundation. In this study, the research subject comes from two reasonable academic doubts on why the gap is wide between the two indicators of Korea and whether the OUR Data Index made proper evaluation on Korea's open government data. Based on the assumption that there may be some critical points in the measuring method of OUR Data Index, the study conducted a comparison of the two indicators. The result found that first, the two indicators almost had no correlation to each other; second, OUR Data Index had a more vague evaluation framework as well as less amount of government data for evaluation than ODB; third, while the government support takes a significant share in the OUR Data Index, it is considered as a mere input element; and fourth, the OUR Data Index does not evaluate the impact of open government data, whereas ODB includes the impact of open data on the government, economy, and society.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.501-508
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• 2015

This study intends to look into the perception gap among Korean and Chinese consumers regarding the product attitudes toward smart phones and repurchase intention as well as the user experience. First, this study showed that there are gaps among Korean and Chinese consumers, regarding smart phones, toward their experiences of usage satisfaction, usefulness, design satisfaction, and evaluation from other people and that Chinese consumers have higher awareness of every experience element concerning UI than Korean consumers. Second, concerning the difference in the product attitudes toward smart phones, it turns out that Chinese consumers also have higher awareness of it than Korean consumers. Third, regarding the difference in repurchase intention for smart phones among Korean and Chinese consumers, this study shows that Chinese consumers are likely to have more intention than Korean consumers. because their average value is higher than Korean consumers' even though the difference are not statistically significant. This study is expected to have academic meaning(significance) for providing basic materials of comparative study between two countries regarding the user experience about smart phone as well as some useful implications for the competitive power improvement of Korean smart phone related companies in China.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.576-583
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• 2018

Silicon carbide is considered to be a potentially useful material for high-temperature electronic devices, as its band gap is larger than that of silicon and the p-type and/or n-type conduction can be controlled by impurity doping. Particularly, porous n-type SiC ceramics fabricated from ${\beta}-SiC$ powder have been found to show a high thermoelectric conversion efficiency in the temperature region of $800^{\circ}C$ to $1000^{\circ}C$. For the application of SiC thermoelectric semiconductors, their figure of merit is an essential parameter, and high temperature (above $800^{\circ}C$) electrodes constitute an essential element. Generally, ceramics are not wetted by most conventional braze metals,. but alloying them with reactive additives can change their interfacial chemistries and promote both wetting and bonding. If a liquid is to wet a solid surface, the energy of the liquid-solid interface must be less than that of the solid, in which case there will be a driving force for the liquid to spread over the solid surface and to enter the capillary gaps. Consequently, using Ag with a relatively low melting point, the junction of the porous SiC semiconductor-Ag and/or its alloy-SiC and/or alumina substrate was studied. Ag-20Ti-20Cu filler metal showed promise as the high temperature electrode for SiC semiconductors.

• The Journal of the Korea Contents Association
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• v.14 no.5
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• pp.107-116
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• 2014

The purpose of this study is to verify the applicability of concept mapping in the process of planning social welfare program based on community network. Concept mapping is a kind of decision-making method that structuralized complex ideas and presented visually. Already, concept mapping is widely utilized in counseling, nursing and public health area to plan and evaluation their program and service. For recent, effectiveness of concept mapping has been reported. Concept mapping is a effective decision-making method that they recognize outcome gap between service provider and client, reach the outcome's consensus in counseling and nursing, medical area. In this study, we conceptualized 3rd year outcomes of Community Impact Project that was supported from Busan Chest using concept mapping. This CI project intervenes children and youth who lives in Buk-gu, Busan. Concept mapping has six stages-preparation, collecting ideas, structuring statements, representing statement, interpreting the results of the analysis, applying the results. We followed these steps. The participants were working at social welfare organizations, total 11 persons. We obtained 60 statements and analyzed using multidimensional scaling. we collected 5 clusters, cluster 1 'awareness and attitude change of children and youth', cluster 2 'social system change of children and youth', cluster 3 'friendly community formation', cluster 4 'community people change', cluster 5 'service provider change'. As a result, among total 5 clusters formed, 'awareness and attitude change of children and youth' came to the strongest outcomes. When concept mapping was applied to the program planning, the consensus of the opinion came easily in the decision-making process, and the participants were empowered. In addition, clear conceptualization on each element of the program planning was made.

• The Journal of the Petrological Society of Korea
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• v.6 no.3
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• pp.166-184
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• 1997

The Wondong caldea is a deeply eroded structure that offers spectacular exposures through the core and margins of a resurgent caldera. The Wondong Tuff and the postcollapse intrusions range from medium-silica rhyolite to rhyodacite in composition and the postcollapse lava and tuff, preresurgent and resurgent intrusions also range from medium-silica rhyolite to an-desite, which jump to gap dacite composition. The continuous compositional zonations generally define a large stratified magma system in the postcollapse and resurgent magma chamber. Isotopic and trace element evidence suggest that the compositional zonations might have resulted from the differentiations from crystal fractionations of a parental andesitic magma, accompanying a little contamination from the crustal assimilations near the chamber roof and wall. But chemically and isotopically distinct late intusions might have resulted from emplacement of any different magma batch.

• Journal of Arbitration Studies
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• v.21 no.2
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• pp.27-46
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• 2011

In the intellectual based society of the 21th century, intellectual property of nation and enterprise management has been the key element of nation's competitiveness and development. Therefore in countries like Korea, China, and many other countries, intellectual property of advancement strategy are being constructed and intellectual properties are protected at national level. Top priority task of protecting the intellectual property is to efficiently resolute intellectual property right disputes. Considering the nature of intellectual property right and arbitrage system, arbitration to solve intellectual property disputes is realistically the best method. However, not all cases of them are qualified. In order to relieve the intellectual property disputes through arbitration, qualification must be obtained. During the process, generally and globally, intellectual property right dispute is evaluated by three parts, intellectual property right contract dispute, intellectual property right violation dispute, and intellectual property right validity dispute. Based on UN's "Convention on the Recognition and Enforcement of Foreign Arbitral Awards Agreement" in 1958, June 10th, in New York, both arbitrage organization and judgment can be approved in both Korea and China countries. However, as of today, there is a big gap of arbitration qualification between two countries, which can be troublesome if intellectual property right disputes arise. For instance, in Korea, intellectual property right contract disputes and intellectual property right violation disputes are both generally accepted as arbitration qualification. However for intellectual property right validity dispute, arbitration qualification is only accepted for non-registered intellectual property as in copyright entity. It does not apply to other registered intellectual property right as in patents. In China, arbitration qualification is accepted for intellectual property right contract dispute, and also accepted for intellectual property right violation dispute to copyrights but restricted to others. As for intellectual property right validity dispute, arbitration qualification is completely denied. Therefore, when there is an intellectual property right dispute between Korea and China, the biggest problem is whether China will accept arbitrage judgments made in Korea. Theoretically, arbitrage judgement made in Korea should be also accepted in China's court. However, considering the criticism of China's passive nature of arbitration qualification for its own local intellectual property right disputes, it's very unlikely they'll actively accept arbitrary judgment made in foreign countries. Korea and China must have a more open minded approach for intellectual property disputes and arbitration qualification. Base on WTO's Intellectual Property Right Agreement, it's being defined as private right. Therefore, sovereign principle should be the basic principle of solving intellectual property right disputes. Currently, arbitration qualification is expanding internationally. So both Korea and China must also follow the trend expand the arbitration qualification with a more open minded and forward looking approach, for the good of intellectual property disputes.