• Journal for History of Mathematics
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• v.25 no.4
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• pp.53-67
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• 2012

Today, it is necessary to calculate orbits with high accuracy in space flight. The key words of Poincar$\acute{e}$ in celestial mechanics are periodic solutions, invariant integrals, asymptotic solutions, characteristic exponents and the non existence of new single-valued integrals. Poincar$\acute{e}$ define an invariant integral of the system as the form which maintains a constant value at all time $t$, where the integration is taken over the arc of a curve and $Y_i$ are some functions of $x$, and extend 2 dimension and 3 dimension. Eigenvalues are classified as the form of trajectories, as corresponding to nodes, foci, saddle points and center. In periodic solutions, the stability of periodic solutions is dependent on the properties of their characteristic exponents. Poincar$\acute{e}$ called bifurcation that is the possibility of existence of chaotic orbit in planetary motion. Existence of near exceptional trajectories as Hadamard's accounts, says that there are probabilistic orbits. In this context we study the eigenvalue problem in early 20th century in three body problem by analyzing the works of Darwin, Bruns, Gyld$\acute{e}$n, Sundman, Hill, Lyapunov, Birkhoff, Painlev$\acute{e}$ and Hadamard.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.412-425
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• 2016

Recently, the influence of the residential value of new town apartment houses has been increasing in the housing market; however, there has been little study on the relationship between the housing value and customer loyalty. This study analyzed the influence of the housing value on housing satisfaction and customer loyalty. To this end, this study conducted a survey targeting 519 residents in the second term new town. Accordingly, basic statistics, reliability and hypothesis test were carried out using SPSS 21.0 and ANOVA as an analysis method. The study results are as follows. First, as a result of factor analysis of the housing value, the factor was analyzed as 6 sorts, such as safety, sociality, convenience, economic feasibility, aesthetics, and comfort. Second, safety, comfort, and convenience among the factors in the housing value were found to have a significant influence on the housing satisfaction. This means that the concepts of property and assets reflect the development of new urban city apartments. Third, a new town house purchaser's positive housing value and housing satisfaction were found to increase customer loyalty. This greater satisfaction of the current residential apartment dwellers means that they are more likely to introduce their relatives and neighbors. These results suggest that a positive outlook of a new town householder on the housing value and housing satisfaction will eventually work more on revitalizing the housing market.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.311-316
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• 2017

The network analysis method has emerged as a new methodology for various disciplines, due to its ability to provide a representative knowledge network of references, co-authors and keywords. Bulletproof technology is an interdisciplinary field involving various disciplines, such as material mechanics, structural mechanics, and ballistics, so it is essential to keep up with the recent trends in technological research. In this research, the recent R&D trends in the field of bulletproof materials were analyzed using keyword based network analysis. From the results, the core keywords were identified as 'Composite', 'Model' and 'Head' using the scholar search engine, google scholar. The centrality analysis for the core keywords showed that bulletproof technology has developed in 3 different areas, viz. material, structure and effects. To the best of our knowledge, this is the first application of (network analysis?) to bulletproof technology. Moreover, we are also convinced that the results of this study will be useful for defense technology planning and determining the direction of R&D in the field of bulletproof technology.

• Restorative Dentistry and Endodontics
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• v.29 no.6
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• pp.504-514
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• 2004

This study compared the dentin shear bond strengths of currently used dentin bonding agents that were irradiated with an LED (Elipar FreeLight, 3M-ESPE) and a halogen light (VIP, BISCO). The optical characteristics of two light curing units were evaluated. Extracted human third molars were prepared to expose the occlusal dentin and the bonding procedures were performed under the irradiation with each light curing unit. The dentin bonding agents used in this study were Scotchbond Multipurpose (3M ESPE), Single Bond (3M ESPE), One-Step (Bisco), Clearfil SE bond (Kuraray), and Adper Prompt (3M ESPE), The shear test was performed by employing the design of a chisel-on-iris supported with a Teflon wall. The fractured dentin surface was observed with SEM to determine the failure mode. The spectral appearance of the LED light curing unit was different from that of the halogen light curing unit in terms of maximum peak and distribution. The LED LCU (maximum peak in 465 nm) shows a narrower spectral distribution than the halogen LCU (maximum peak in 487 nm). With the exception of the Clearfil SE bond (P < 0.05), each 4 dentin bonding agents showed no significant difference between the halogen light-cured group and the LED light-cured group in the mean shear bond strength (P > 0.05). The results can be explained by the strong correlation between the absorption spectrum of camphoroquinone and the narrow emission spectrum of LED.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.4
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• pp.500-507
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• 1998

Using a sledge net, the benthic amphipods were taken over one cycle of the neap and spring tides in January 1993 at the sandy shore surf zone of Dolsando, southern Korea. From these samples, we investigated the diel and tidal effects on the intraspecific zonation of Pontogeneia rostrata. The density of p. rostrata was higher during neap tide than spring. Of three categories (adult males and females and juveniles), juveniles and males attained to its highest density during neap and spring tides, respectively. Length- frequency data show that the high mortality of juveniles seemed to occur in winter. In the surface at night, it is significant that juveniles were significantly more abundant during neap tide than spring, whereas both adult males and females were more abundant during spring tide than neap. This suggests that the vortical migration patterns of juveniles and adults vary with the type of tides. During flood of spring tide, more than $90\%$ of population collected at the area above the mean sea level (MSL) were adults. With a decrease of female/male ratio, size of males increased there but that of female did not change, indicating an active migration of large males. This behavior can provide an extension of distribution area far large males, and also give a competitive advantage to large male against small one for mate and feeding. Although adult p. rostrata was collected at 100 cm above MSL at night during spring tide, a major portion of population as usually present on the shore below MSL. The center of zonation was restricted from 50 cm to 250 cm below MSL.

• Journal of Korean Home Economics Education Association
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• v.29 no.3
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• pp.105-124
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• 2017

This study aimed at developing an educational program for South Korean adolescents on North Korean family living culture so that the students become familiar with the values and everyday lifestyles of North Korea. Understanding of North Korean culture is considered important as a foundation for social integration in prospect of future reunification. The contents of the program were developed based on the analysis of North Korean defectors' interviews and review of the literature and media reports on North Korean family culture. The program consists of 12 units of 40-minute sessions with the following topics: economy and consumption, leisure activities, family relationships, dating and spouse choices, fashion changes, clothing acquisition and care, food choices and local diets, dietary problems, housing, and neighborhood. The program was implemented between December 21 and 30, 2015 in a middle school located in Seoul. This program is expected to be useful in preparing the students as future leaders to create harmonious family living culture in the reunified Korea.

• 한국과학기술학회:학술대회논문집
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• 2008.06a
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• pp.1-34
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• 2008

본 인식 조사에서 나타난 결과와 개선 방안의 도출과 관련한 시사점을 요약하면 다음과 같다. 첫째, 국내 연구부정행위 실태는 우려할만한 수준으로 나타났다. 위조, 변조, 표절, 부당한 저자 배분, 업적 부풀림 등 연구부정행위에 대해 연구비 유용이나 횡령보다 훨씬 더 만연한 것으로 응답하였다. 연구부정행위가 발각되는 정도에 대해서는 의견이 분분하였으나 처벌의 수위는 엄격하지 않다고 생각하는 것으로 나타났다. 본인의 연구윤리 의식이 타인에 비해 높은 것으로 자부하고 있으나 부정행위 인지시의 행동에 대해서는 바람직하다고 생각하는 행동과 자신의 예상 행동 사이에 괴리를 보였고, 바람직하다고 생각하는 행동도 매우 소극적인 것으로 나타났다. 부정행위 실태 조사에서 나타난 중요한 사실은 주로 기초 연구를 수행하는 과기부/교육부 사업 수행자가 응용이나 개발 연구를 수행하는 산자부/정통부 사업 수행자에 비해 자신의 연구 분야에서 연구부정행위가 훨씬 더 만연해 있는 것으로 응답한 것이다. 둘째, 가장 심각한 연구윤리 저해 요인에 대해서는 단기간 성과의 강조, 연구 수주의 경쟁 심화, 정량적 성과 주의 등을 꼽았으며, 전체적으로 개인적/문화적 요인보다는 구조적/조직적 요인, 특히 구조적 요인이 더 중요한 것으로 인식하고 있었다. 신뢰도 분석 결과 제3장에서의 분석을 바탕으로 본 연구에서 제시한 구조적, 조직적, 개인적, 문화적 요인의 구분은 유효한 구분으로 나타났다. 대학에 비해 정출연 소속 연구자들이 구조적 요인이 연구부정행위와 더 관련이 많다고 인식하고 있었으며, 기업 소속 연구자들은 구조적 요인이나 조직적 요인과의 관련성이 더 적은 것으로 인식하고 있어 본 연구에서 제시한 여러 저해 요인들이 대학이나 정출연에 더욱 밀접한 것으로 나타났다. 개인적 요인에 대해서는 여성이나 고연령층에서 부정행위와의 관련성을 더 크게 느끼고 있었다. 셋째, 개선 방안에 대해서는 과도한 연구비의 집중 방지, 소규모 개인과제 확대, 평가의 전문성과 공정성 확보를 가장 효과적인 방안으로 인식하고 있었다. 부정행위에 대한 처벌의 강화와 양적 평가의 개선에 대해서도 효과를 높이 기대하고 있었다. 연구윤리 교육이나 상대 평가의 강화, 진실성 검증 시스템의 보완 등에 대해서는 큰 효과를 기대하지 않고 있었으나 이는 국내에서 그동안 연구윤리에 대한 체계적 교육이나 진실성 검증 시스템이 존재하지 않은 탓에 연구자들이 그 효과를 잘 인식하지 못하고 있다는 점이 고려되어야 할 것이다. 개선 방안을 크게 평가, 선정, 수행, 연구윤리의 인프라로 구분하였을 때에는 선정과 평가와 관련된 개선이 시급한 것으로 인식하고 있었다. 사업별로는 과기부/교육부 사업 수행자가 선정과 관련된 개선의 효과를 더욱 크게 느끼고 있었고 소속기관으로는 대학 연구자들이 더욱 크게 느끼고 있어, 소규모 과제의 확대와 연구비 집중 문제 해결, 경쟁 완화 등이 대학과 기초연구분야에 더욱 절실하다는 것을 나타내었다. 전체적으로 제시된 세부 항목에 대해 과기부/교육부 사업 수행자가 산자부/정통부 사업 수행자보다 효과성을 높게 보고 있는 것은 연구부정행위 실태에 대해서도 더 심각하게 인식하는 것과 맥락을 같이한다고 볼 수 있다. 따라서 본 연구에서 제안하는 여러 개선 방안들을 단계적으로 적용한다고 할 때 우선 기초연구나 개인 단위 과제 중심으로 적용하는 것이 효과성이나 필요성의 측면에서 모두 바람직한 것으로 판단된다.

• Journal of Science and Technology Studies
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• v.19 no.3
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• pp.167-200
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• 2019

In recent years, the material has mattered to the humanities and social sciences in the West and feminism is no exception. It is a notable change that feminist analyses, which had previously shown critiques against science and technology, attempted to build new engagements with matter. STS (science and technology studies) has also accumulated scholarships and developed conceptual tools on the thing or the existence itself through "the ontological turn." The objective of this paper is not to introduce new materialism or new material feminism in full, but to reveal the possibility and potential of doing science, technology and women studies by selectively relying on the achievement of new materialism feminism. This article shows a way to study women's practice of science and technology by analyzing the case of plastic surgery practices through the ontological concepts of STS, particularly those of Annemarie Mol, Karen Barad, and Charis Thompson, and proposes a new engagement among new materialism, feminism, and STS. This article is organized as follows. First of all, after briefly discussing main issues in new material feminism, I will show the limitations of previous feminist studies of plastic surgery under the light of new material feminism. The rest of the article introduces the conceptual tools of ontological STS, describes plastic surgery practices with those tools, and finally provides their feminist implications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.8
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• pp.1349-1355
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• 2008

Recently many short-range transceiver systems, such as ZigBee, Bluetooth and RFID(Radio Frequency Identification), have been developed. These systems are mostly low-power transceivers. In the near future many more low-power transceivers are appeared for WPAN(Wireless Personal Area Network) and interference mitigation technologies are necessary to the low-power transceivers for using frequency resources efficiently. In this paper we consider two methods for sharing frequency resources. The first case is that a frequency band previously assigned fer a certain system is shared and the second case is that the white frequency band is shared. We study the method and conditions for sharing frequency resources in the above two cases. When a frequency band is shared with ZigBee, RFID, DCP (Digital Cordless Phone) and Bluetooth as an example for the first case, the sharing conditions are investigated and the results are presented. We propose a balancing factor to maintain an equal transmitting conditions between systems having a different interference mitigation technique. In the interference simulation we use FH(Frequency Hopping) as a reference system and 0.9 of a balancing factor for LBT(Listen Before Talk) and 0.8 for DS(Direct Spreading). From the simulation results we know that a balancing factor reduces interference probability therefore many more systems can be operated in the same frequency bands compared with the case without using a balancing factor.

• Korean Journal of Remote Sensing
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• v.23 no.2
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• pp.71-87
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• 2007

In this study, 14 heavy snow events in Yeongdong area which are local phenomena are analyzed using MODIS cloud products provided from NASA/GSFC. The clouds of Yeongdong area at observed at specific time by MODIS are classified into A, B, C Types, based on the characteristic of cloud properties: cloud top temperature, cloud optical thickness, Effective Particle Radius, and Cloud Particle Phase. The analysis of relations between cloud properties and precipitation amount for each cloud type show that there are statistically significant correlations between Cloud Optical Thickness and precipitation amount for both A and B type and also significant correlation is found between Cloud Top Temperature and precipitation amount for A type. However, for C type there is not any significant correlations between cloud properties and precipitation amount. A-type clouds are mainly lower stratus clouds with small-size droplet, which may be formed under the low level cold advection derived synoptically in the East sea. B-type clouds are developed cumuliform clouds, which are closely related to the low pressure center developing over the East sea. On the other hand, C-type clouds are likely multi-layer clouds, which make satellite observation difficult due to covering of high clouds over low level clouds directly related with Yeongdong heavy snow. It is, therefore, concluded that MODIS cloud products may be useful except the multi-layer clouds for understanding the mechanism of heavy snow and estimating the precipitation amount from satellite data in the case of Yeongdong heavy snow.